Co-reporter:Yuewei Zhang, Yang Miao, Xiaoxian Song, Yu Gao, Zuolun Zhang, Kaiqi Ye, and Yue Wang
The Journal of Physical Chemistry Letters October 5, 2017 Volume 8(Issue 19) pp:4808-4808
Publication Date(Web):September 20, 2017
DOI:10.1021/acs.jpclett.7b02213
White-light-emitting single molecules have attracted broad attention because of their great potential for use in flat-panel displays and future light sources. We report a unique molecule of 3-(diphenylamino)-9H-xanthen-9-one (3-DPH-XO), which was found to exhibit bright white-light emission in the solid state caused by the spontaneous formation of a mixture with different polymorphs. Single-crystal analyses demonstrate that noncovalent interactions (such as π···π stacking, hydrogen bonding, and C–H···π interactions) induce different stacking arrangements (polymorphs A, B, and C) with different photophysical properties in a molecular solid. In addition, crystals B and C with the acceptor···acceptor stacking feature show the thermally activated delayed fluorescence (TADF) characteristics, indicating that appropriate noncovalent interactions could enhance the reverse intersystem crossing process and consequently lead to delayed fluorescence. This discovery provides an effective strategy for the design of new white-light-emitting single molecules as well as TADF materials.
Co-reporter:Shipan Wang, Zong Cheng, Xiaoxian Song, Xianju Yan, Kaiqi Ye, Yu Liu, Guochun Yang, and Yue Wang
ACS Applied Materials & Interfaces March 22, 2017 Volume 9(Issue 11) pp:9892-9892
Publication Date(Web):March 1, 2017
DOI:10.1021/acsami.6b14796
Highly efficient long-wavelength thermally activated delayed fluorescence (TADF) materials are developed using 2,3-dicyanopyrazino phenanthrene (DCPP) as the electron acceptor (A), and carbazole (Cz), diphenylamine (DPA), or 9,9-dimethyl-9,10-dihydroacridine (DMAC) as the electron donor (D). Because of the large, rigid π-conjugated structure and strong electron-withdrawing capability of DCPP, TADF molecules with emitting colors ranging from yellow to deep-red are realized with different electron-donating groups and π-conjugation length. The connecting modes between donor and acceptor, that is, with or without the phenyl ring as π-bridge, are also investigated to study the π-bridge effect on the thermal, photophysical, electrochemical, and electroluminescent properties. Yellow, orange, red, and deep-red organic light-emitting diodes (OLEDs) based on DCPP derivatives exhibit high efficiencies of 47.6 cd A–1 (14.8%), 34.5 cd A–1 (16.9%), 12.8 cd A–1 (10.1%), and 13.2 cd A–1 (15.1%), with Commission Internationale de L’Eclairage (CIE) coordinates of (0.44, 0.54), (0.53, 0.46), (0.60, 0.40), and (0.64, 0.36), respectively, which are among the best values for long-wavelength TADF OLEDs.Keywords: dicyanopyrazino phenanthrene derivatives; intramolecular charge transfer excited states; long-wavelength emitters; organic light-emitting diodes; thermally activated delayed fluorescence;
Co-reporter:Zhimin Yan;Yanping Wang;Junqiao Ding;Lixiang Wang
Journal of Materials Chemistry C 2017 vol. 5(Issue 46) pp:12221-12227
Publication Date(Web):2017/11/30
DOI:10.1039/C7TC04269H
Two new furo[3,2-c]pyridine-based Ir complexes, namely (4-MeOpfupy)2Ir(acac) and (3-MeOpfupy)2Ir(acac), were designed and synthesized by introducing a methoxyl group into the 4- and 3-positions of the phenyl ring on the C^N ligand. It was found that the position of the methoxyl group has an important influence on the electrochemical and photophysical properties, as well as electrophosphorescent device performance. Compared with the reference complex (pfupy)2Ir(acac) without any methoxyl group (538 nm), (4-MeOpfupy)2Ir(acac) with a methoxyl group at the 4-position shows a blue-shifted emission peak at 523 nm originating from the methoxyl-induced enhancement of the LUMO level, whereas (3-MeOpfupy)2Ir(acac) with a methoxyl group at the 3-position shows a red-shifted emission peak at 602 nm originating from the methoxyl-induced enhancement of the HOMO level. The corresponding PhOLEDs based on (4-MeOpfupy)2Ir(acac) and (3-MeOpfupy)2Ir(acac) realize highly efficient green and orange electroluminescence with CIE coordinates of (0.37, 0.60) and (0.60, 0.40), revealing a state-of-the-art EQE as high as 29.5% (100.7 cd A−1) and 16.7% (43.9 cd A−1), respectively. These impressive results indicate that methoxyl modification is a valid way to tune the molecular energy levels and emissive color for Ir complexes while not obviously sacrificing the final device performance.
Co-reporter:Yang Miao;Tong Yang;Zong Cheng;Yuewei Zhang;Jingying Zhang
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 21) pp:13166-13174
Publication Date(Web):2017/10/24
DOI:10.1039/C7NJ03061D
Two small molecular cathode interlayer (CIL) materials with pyridinium ion or quaternary ammonium ion terminated 1,2,3-trihexyloxybenzene as pendant polar groups and anthrathiadiazole-4,11-dione (ATD) as a conjugated backbone, namely PBATD and TBATD, were synthesized for PCDTBT:PC71BM (PCDTBT:poly[poly[N-9′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]]; PC71BM:[6,6]-phenyl C71-butyric acid methyl ester) based polymer solar cells (PSCs). A dramatic improvement in the device performance was observed when the CILs were inserted between the active layer and the Al electrode. Especially, the device modified by quaternary ammonium ion terminated TBATD exhibits a power conversion efficiency (PCE) of 7.26%, which was 1.4 times that of the device with bare Al as the cathode, due to the simultaneously enhanced open-circuit voltage (Voc), short-circuit current density (Jsc) and fill factor (FF). Importantly, the Voc (0.93 V) achieved for the TBATD modified device was among the top values that used the same kind of active layer in conventional single-junction PSCs so far. It demonstrated that the CILs presented in this study may be a promising candidate for applications in high performance PSCs.
Co-reporter:Chenglong Li;Ruihong Duan;Baoyan Liang;Guangchao Han;Shipan Wang;Kaiqi Ye; Dr. Yu Liu; Dr. Yuanping Yi; Dr. Yue Wang
Angewandte Chemie 2017 Volume 129(Issue 38) pp:11683-11687
Publication Date(Web):2017/09/11
DOI:10.1002/ange.201706464
AbstractThe design and synthesis of highly efficient deep red (DR) and near-infrared (NIR) organic emitting materials with characteristic of thermally activated delayed fluorescence (TADF) still remains a great challenge. A strategy was developed to construct TADF organic solid films with strong DR or NIR emission feature. The triphenylamine (TPA) and quinoxaline-6,7-dicarbonitrile (QCN) were employed as electron donor (D) and acceptor (A), respectively, to synthesize a TADF compound, TPA-QCN. The TPA-QCN molecule with orange-red emission in solution was employed as a dopant to prepare DR and NIR luminescent solid thin films. The high doped concentration and neat films exhibited efficient DR and NIR emissions, respectively. The highly efficient DR and NIR organic light-emitting devices (OLEDs) were fabricated by regulating TPA-QCN dopant concentration in the emitting layers.
Co-reporter:Zhimin Yan;Yanping Wang;Jiaxiu Wang;Junqiao Ding;Lixiang Wang
Journal of Materials Chemistry C 2017 vol. 5(Issue 39) pp:10122-10125
Publication Date(Web):2017/10/12
DOI:10.1039/C7TC03937A
A novel furo[3,2-c]pyridine based Ir complex, namely (pfupy)2Ir(acac), has been developed by replacing sulfur with oxygen in the C^N ligand. Compared with the thiophene-containing (pthpy)2Ir(acac), the LUMO level is elevated while the HOMO level remains almost unchanged for the resultant furan-containing (pfupy)2Ir(acac). As a consequence, the emissive maximum is blue-shifted from 556 nm of (pthpy)2Ir(acac) to 538 nm of (pfupy)2Ir(acac) together with an improved photoluminescence quantum yield of 0.80. The corresponding device based on (pfupy)2Ir(acac) realizes a record-high external quantum efficiency (EQE) of 30.5% (110.5 cd A−1) without any out-coupling technology. Even at a luminance of 1000 and 5000 cd m−2, the EQE still remains at 26.6% (96.4 cd A−1) and 25.6% (92.7 cd A−1), respectively, indicative of the gentle efficiency roll-off. The results clearly demonstrate the great potential of furan-based functional materials applied in OLEDs.
Co-reporter:Chenglong Li;Zhiqiang Li;Xianju Yan;Yuewei Zhang;Zuolun Zhang
Journal of Materials Chemistry C 2017 vol. 5(Issue 8) pp:1973-1980
Publication Date(Web):2017/02/23
DOI:10.1039/C6TC05639C
Blue organic light-emitting diodes (OLEDs) are crucial for flat-panel displays and solid-state lighting. Regarding the practical application of OLEDs, high luminance and efficiencies at a low driving voltage, as well as a simple device structure, are highly desirable. However, blue OLEDs fulfilling these requirements are rare. Herein, two new sky-blue emitters, TPA-An-PPI and PCz-An-PPI, with the integration of wide-bandgap phenanthro[9,10-d]imidazole, anthracene and aromatic amine groups have been synthesized. They possess good thermal stability, bright emission in the solid state, as well as the bipolar carrier-transporting ability. Structurally simple non-doped sky-blue OLEDs with TPA-An-PPI as the emitting layer showed high performance, with the maximum luminance (Lmax) of 51 390 cd m−2, the maximum power efficiency (PEmax) of 10.42 lm W−1, and the maximum external quantum efficiency (EQEmax) of 4.61%. More importantly, at a practical high luminance of 1000 cd m−2, the PE and EQE retained high values of 8.48 lm W−1 and 4.60%, respectively, and the corresponding driving voltage was as low as 3.6 V. The performance of the non-doped device based on PCz-An-PPI was also high, although being lower than that of TPA-An-PPI.
Co-reporter:Mingxu Du;Yansong Feng;Dongxia Zhu;Tai Peng;Yu Liu;Martin R. Bryce
Advanced Materials 2016 Volume 28( Issue 28) pp:5963-5968
Publication Date(Web):
DOI:10.1002/adma.201600451
Co-reporter:Chenglong Li, Jinbei Wei, Xiaoxian Song, Kaiqi Ye, Hongyu Zhang, Jingying Zhang and Yue Wang
Journal of Materials Chemistry A 2016 vol. 4(Issue 29) pp:7013-7019
Publication Date(Web):27 Jun 2016
DOI:10.1039/C6TC01975G
Two phenanthro[9,10-d]imidazole (PI) derivatives, 9-N,N-diphenyl-amino-10-(4-(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)anthracene (DPAA-PPI) and 9-N,N-dipheny-amino-10-(4-(1-(4-tert-butylphenyl)-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)anthracene (tBuDPAA-PPI), have been designed and synthesized. The two compounds exhibited high photoluminescence quantum yields (at around 0.80) in the solid state and bipolar carrier transport properties. The non-doped OLEDs using DPAA-PPI and tBuDPAA-PPI as emitting layers showed the maximum power efficiencies (PEs) of 13.9 lm W−1 and 11.4 lm W−1, corresponding to the maximum external quantum efficiencies (EQEs) of 5.2% and 4.1%, respectively. The DPAA-PPI-based OLED exhibited an extremely low turn-on voltage of 2.4 V and its luminescence reached 100, 1000, 10000 and over 100000 cd m−2 under driving voltages of 2.8, 3.6, 5.1 and 7.5 V, respectively.
Co-reporter:Weiping Chen, Junjie Lv, Jianxiong Han, Youchun Chen, Tao Jia, Fenghong Li and Yue Wang
Journal of Materials Chemistry A 2016 vol. 4(Issue 6) pp:2169-2177
Publication Date(Web):18 Jan 2016
DOI:10.1039/C5TA09701K
A new π-conjugated electrolyte bis(dicyanomethylene)-quinacridone with two octyl-pyridium (DCNQA-PyBr) has been synthesized and employed as a solution-processed cathode interlayer (CIL) for polymer solar cells (PSCs). The devices exhibited simultaneously increased open-circuit voltage (Voc), short-circuit current (Jsc) and fill factor (FF). Overall, the PSCs with PCDTBT (poly[N-9′′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]) as a donor and PC71BM ([6,6]-phenyl C71-butyric acid methyl ester) as an acceptor incorporating a 13 nm DCNQA-PyBr interlayer exhibit a power conversion efficiency (PCE) of 6.96%, which is 1.3 times of that of the Al-only device. Most importantly, compared to the reference π-conjugated electrolyte QA-PyBr, DCNQA-PyBr shows much improved electron transport ability and conductivity. As a result, the DCNQA-PyBr based devices only show a slight decrease in electron transport upon increasing the thickness of the CIL, thus allowing a high PCE with a wide CIL thickness range from 5 nm to 40 nm. Furthermore, introducing DCNQA-PyBr as a CIL into the devices based on P3HT:PC61BM (P3HT = poly(3-hexylthiophene), PC61BM = [6,6]-phenyl C61-butyric acid methyl ester) and PTB7:PC71BM (PTB7 = polythieno[3,4-b]-thiophene-co-benzodithiophene) also leads to significantly enhanced device performance, showing high PCEs of 3.91% and 8.23%, respectively. These results confirm DCNQA-PyBr to be a promising CIL material for solution-processed large-area PSCs.
Co-reporter:Weiping Chen
The Journal of Physical Chemistry C 2016 Volume 120(Issue 1) pp:587-597
Publication Date(Web):December 9, 2015
DOI:10.1021/acs.jpcc.5b10954
A series of dicyanomethylenated acridone derivatives, DCNAC-Cn (n = 1, 4, 6) and DPA-DCNAC-C4, are designed and synthesized. They are highly luminescent in the crystalline state but nonemissive in the amorphous state. The interesting crystallization-induced-emission (CIE) behavior is attributed to the restricted torsional vibrations of the molecular skeletons in crystal lattices. DCNAC-Cn-based crystals display obvious molecular-packing-dependent emission properties. The molecular packing of DCNAC-Cn in crystals is easily regulated by modifying the length of alkyl chains, resulting in the tunable emission colors from green to red. A DPA-DCNAC-C4 molecule consisting of a DCNAC acceptor and two diphenylamino donors shows intramolecular charge-transfer (ICT) characteristic and strong near-infrared emission (λem = 707 nm, ΦF = 0.16) in the crystalline state. Mechanical, thermal, and organic-vapor stimuli can reversibly alter the aggregation phases between crystalline and amorphous states. Therefore, this study presents a stimuli-responsive emission on/off switching system with various emission colors (560 to 700 nm).
Co-reporter:Jianxiong Han, Youchun Chen, Weiping Chen, Chengzhuo Yu, Xiaoxian Song, Fenghong Li, and Yue Wang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 48) pp:
Publication Date(Web):November 11, 2016
DOI:10.1021/acsami.6b10900
A new class of organic cathode interfacial layer (CIL) materials based on isoindigo derivatives (IID) substituted with pyridinium or sulfonate zwitterion groups were designed, synthesized, and applied in polymer solar cells (PSCs) with PTB7:PC71BM (PTB7: polythieno[3,4-b]-thiophene-co-benzodithiophene and PC71BM: [6,6]-phenyl C71-butyric acidmethyl ester) as an active layer. Compared with the control device, PSCs with an IID-based CIL show simultaneous enhancement of open-circuit voltage (Voc), short-circuit current (Jsc), and fill factor (FF). Systematic optimizations of the central conjugated core and side flexible alcohol-soluble groups demonstrated that isoindigo-based CIL material with thiophene and sulfonate zwitterion substituent groups can efficiently enhance the PSC performance. The highest power conversion efficiency (PCE) of 9.12%, which is 1.75 times that of the control device without CIL, was achieved for the PSC having an isoindigo-based CIL. For the PSCs with an isoindigo-based CIL, the molecule-dependent performance property studies revealed that the central conjugated core with D-A-D characteristics and the side chains with sulfonate zwitterions groups represents an efficient strategy for constructing high performance CILs. Our study results may open a new avenue toward high performance PSCs.Keywords: cathode interlayer; donor−acceptor organic molecules; isoindigo derivatives; polymer solar cell;
Co-reporter:Zhenyu Zhang; Xiaoxian Song; Shipan Wang; Feng Li; Hongyu Zhang; Kaiqi Ye
The Journal of Physical Chemistry Letters 2016 Volume 7(Issue 9) pp:1697-1702
Publication Date(Web):April 20, 2016
DOI:10.1021/acs.jpclett.6b00704
The successful preparation of two-dimensional (2D) single crystals can promote the development of organic optoelectronic devices with excellent performance. A Schiff base compound salicylidene(4-dimethylamino)aniline with aggregation induced emission (AIE) property was employed as the building block to fabricate 2D thin single crystal plates with scales from around 50 μm to 1.5 cm. Yellow and red emissive polymorphs were concomitantly obtained during crystallization. The single-crystal-to-single-crystal (SC-to-SC) transformation from yellow polymorph to red one was demonstrated. Furthermore, both polymorphs exhibited amplified spontaneous emission (ASE) properties. Interestingly, the red polymorph displayed size-dependent ASE characteristics. The larger red polymorph showed near-infrared ASE with maximum at 706 nm, whereas the smaller one presented red ASE with maximum at 610 nm. These results suggest that the different scale single crystalline thin films with perfect optoelectronic properties may be fabricated by using the organic molecules with 2D assembly feature.
Co-reporter:Yuewei Zhang, Huili Ma, Shipan Wang, Zhiqiang Li, Kaiqi Ye, Jingying Zhang, Yu Liu, Qian Peng, and Yue Wang
The Journal of Physical Chemistry C 2016 Volume 120(Issue 35) pp:19759-19767
Publication Date(Web):August 15, 2016
DOI:10.1021/acs.jpcc.6b05537
Co-reporter:Yunhui Zhu, Yuewei Zhang, Bing Yao, Yanjie Wang, Zilong Zhang, Hongmei Zhan, Baohua Zhang, Zhiyuan Xie, Yue Wang, and Yanxiang Cheng
Macromolecules 2016 Volume 49(Issue 11) pp:4373-4377
Publication Date(Web):June 2, 2016
DOI:10.1021/acs.macromol.6b00430
Co-reporter:Tao Jia, Weilong Zhou, Youchun Chen, Jianxiong Han, Lu Wang, Fenghong Li and Yue Wang
Journal of Materials Chemistry A 2015 vol. 3(Issue 8) pp:4547-4554
Publication Date(Web):08 Jan 2015
DOI:10.1039/C4TA06601D
A new cathode interlayer (CIL) material metallophthalocyanine (MPc) derivative 1,4,8,11,15,18,22,25-octaoctyloxy-2,3,9,10,16,17,23,24-octa-[N-methyl-(3-pyridyloxy)] zinc-ylphthalocyanine iodide (1:8) (ZnPc(OC8H17OPyCH3I)8) was synthesized and applied in polymer solar cells (PSCs) based on PTB7:PC71BM (PTB7 = thieno[3,4-b]thiophene/benzodithiophene, PC71BM = [6,6]-phenyl C71-butyric acidmethyl ester), P3HT:PC61BM (P3HT = poly(3-hexylthiophene), PC61BM = [6,6]-phenyl C61-butyric acidmethyl ester) or PCDTBT:PC71BM (PCDTBT = poly[N-9′′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]) as an active layer. As a result, power conversion efficiency (PCE) values of the PSCs were 8.52%, 4.02% and 6.88%, respectively, which are much higher than those of corresponding PSCs with the Al-only cathode. It indicates that ZnPc(OC8H17OPyCH3I)8 is a new promising candidate as a universal CIL for highly efficient PSCs. Compared to VOPc(OPyCH3I)8 (2,3,9,10,16,17,23,24-octakis-[N-methyl-(3-pyridyloxy)] vanadylphthalocyanine iodide (1:8)), the PSC with ZnPc(OC8H17OPyCH3I)8 as a CIL has higher short-circuit current and fill factor because ZnPc(OC8H17OPyCH3I)8 can form a better, denser, and more uniform film on the active layer than VOPc(OPyCH3I)8 as demonstrated by atomic force microscopy (AFM), energy-dispersive spectrum mapping on scan electron microscopy (SEM-EDS mapping) and contact angle measurements.
Co-reporter:Weiping Chen, Kui Tian, Xiaoxian Song, Zuolun Zhang, Kaiqi Ye, Gui Yu, and Yue Wang
Organic Letters 2015 Volume 17(Issue 24) pp:6146-6149
Publication Date(Web):November 25, 2015
DOI:10.1021/acs.orglett.5b03155
Two 11-ring-fused quinacridone derivatives, TTQA and DCNTTQA, have been synthesized by ferric chloride mediated cyclization and Knoevenagel reaction. Replacement of the carbonyl groups (in TTQA) with dicyanoethylene groups (in DCNTTQA) not only red-shifted the emission to the near-infrared region but also led to a nonplanar skeleton that significantly improved the solubility of DCNTTQA. Moreover, dicyanoethylene groups rendered DCNTTQA low-lying HOMO and LUMO levels. DCNTTQA-based solution-processed field-effect transistors showed a hole mobility up to 0.217 cm2 V–1 s–1.
Co-reporter:Shipan Wang, Yuewei Zhang, Weiping Chen, Jinbei Wei, Yu Liu and Yue Wang
Chemical Communications 2015 vol. 51(Issue 60) pp:11972-11975
Publication Date(Web):19 Jun 2015
DOI:10.1039/C5CC04469C
Achieving high power efficiencies at high-brightness levels is still an important issue for organic light-emitting diodes (OLEDs) based on the thermally activated delayed fluorescence (TADF) mechanism. Herein, enhanced electroluminescence efficiencies were achieved in fluorescent OLEDs using a TADF molecule, (4s,6s)-2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN), as a host and quinacridone derivatives (QA) as fluorescent dopants.
Co-reporter:Chenglong Li, Shipan Wang, Weiping Chen, Jinbei Wei, Guochun Yang, Kaiqi Ye, Yu Liu and Yue Wang
Chemical Communications 2015 vol. 51(Issue 53) pp:10632-10635
Publication Date(Web):21 May 2015
DOI:10.1039/C5CC03492B
Two deep blue emitting materials PPI-PPITPA and PPI-PPIPCz with dual carrier transport properties and small singlet–triplet splitting features are designed and synthesized. PPI-PPITPA and PPI-PPIPCz were used not only as non-doped emitting layers to fabricate highly efficient deep blue OLEDs, but also as hosts to construct high performance green, yellow and red phosphorescent OLEDs.
Co-reporter:Liang Han, Yuewei Zhang, Weiping Chen, Xiao Cheng, Kaiqing Ye, Jingying Zhang and Yue Wang
Chemical Communications 2015 vol. 51(Issue 21) pp:4477-4480
Publication Date(Web):16 Feb 2015
DOI:10.1039/C5CC00476D
Acenaphtho[1,2-k]fluoranthene derivatives DPAF-n as new building blocks for one-dimensional (1D) structure assembly have been developed and employed to fabricate luminescent twisted nano/micro-wires; and the DPAF rigid core attached via flexible alkyl chains with suitable lengths is critical for the formation of twisted architectures.
Co-reporter:Tao Jia, Jianxiong Han, Weilong Zhou, Lu Wang, Mengchun Wu, Weiping Chen, Youchun Chen, Fenghong Li, Yue Wang
Solar Energy Materials and Solar Cells 2015 Volume 141() pp:93-100
Publication Date(Web):October 2015
DOI:10.1016/j.solmat.2015.04.040
•ZnPc[S(CH2)2N(CH3)3I]8 was synthesized and successfully used as a cathode interlayer in the polymer solar cells (PSCs).•ZnPc[S(CH2)2N(CH3)3I]8 decreased work function of cathode increased hole mobility and facilitated a balance of electron and hole transport in the PSCs.A water-soluble metallophthalocyanine (MPc) derivative, 2,3,9,10,16,17,23,24-octakis(2-trimethylaminoethylsulfanyl) zincylphthalocyanine octaiodine (ZnPc[S(CH2)2N-(CH3)3I]8) was synthesized and applied in polymer solar cells (PSCs). A power conversion efficiency (PCE) of 7.06% has been obtained when the ZnPc[S(CH2)2N(CH3)3I]8 was utilized as a cathode interlayer in the PSCs based on a blend of PCDTBT (poly[N-9″-hepta-decanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]) and PC71BM ([6,6]-phenyl C71 butyric acid methyl ester) as an active layer. Ultraviolet photoemission spectroscopic (UPS), atomic force microscopy (AFM), contact angle (θ) and mobility measurements demonstrated that an introduction of ZnPc[S(CH2)2N(CH3)3I]8 between active layer and cathode decreased work function of cathode, increased hole mobility and facilitated a balance of electron and hole transport in the PSCs, resulting in a simultaneous improvement of open-circuit voltage, short-circuit current and fill factor.A water-soluble metallophthalocyanine derivative ZnPc[S(CH2)2N(CH3)3I]8 was synthesized and applied in polymer solar cells (PSCs). A power conversion efficiency (PCE) of 7.06% has been obtained when the ZnPc[S(CH2)2N(CH3)3I]8 was utilized as a cathode interlayer in the PSCs based on a blend of PCDTBT and PC71BM as an active layer.
Co-reporter:Fangchao Zhao, Liping Zhu, Yipeng Liu, Yue Wang, Dongge Ma
Organic Electronics 2015 Volume 27() pp:207-211
Publication Date(Web):December 2015
DOI:10.1016/j.orgel.2015.09.025
•Doping-free, hybrid white OLEDs with fluorescent blue, and phosphorescent green and red emissive layers are reported.•OLEDs with doping-free process show advantages in EL performances over doped devices with similar structures.•Device with ultra-thin green phosphorescent EML in HTL is more efficient in utilization of excitons.•Ultra-thin green phosphorescent EML in HTL makes EL spectrum more stable than that in ETL.Industrialized white organic light-emitting diodes (OLEDs) currently require host-guest doping, a complicated process necessitating precise control of the guest concentration to get high efficiency and stability. Two doping-free, hybrid white OLEDs with fluorescent blue, and phosphorescent green and red emissive layers (EMLs) are reported in this work. An ultra-thin red phosphorescent EML was situated in a blue-emitting electron transport layer (ETL), while the ultra-thin green phosphorescent EML was placed either in the ETL (Device 1), or the hole transport layer (HTL) (Device 2). Device 2 exhibits higher efficiency and more stable spectrum due to the enhanced utilization of excitons by ultra-thin green EML at the exciton generation zone within the HTL. Values of current efficiency (CE), power efficiency (PE), and CRI obtained for the optimized hybrid white OLEDs fabricated through a doping-free process were of 23.2 cd/A, 20.5 lm/W and 82 at 1000 cd/m2, respectively.
Co-reporter:Shipan Wang;Xianju Yan;Zong Cheng;Dr. Hongyu Zhang;Dr. Yu Liu ;Dr. Yue Wang
Angewandte Chemie International Edition 2015 Volume 54( Issue 44) pp:13068-13072
Publication Date(Web):
DOI:10.1002/anie.201506687
Abstract
Significant efforts have been made to develop high-efficiency organic light-emitting diodes (OLEDs) employing thermally activated delayed fluorescence (TADF) emitters with blue, green, yellow, and orange–red colors. However, efficient TADF materials with colors ranging from red, to deep-red, to near-infrared (NIR) have been rarely reported owing to the difficulty in molecular design. Herein, we report the first NIR TADF molecule TPA-DCPP (TPA=triphenylamine; DCPP=2,3-dicyanopyrazino phenanthrene) which has a small singlet–triplet splitting (ΔEST) of 0.13 eV. Its nondoped OLED device exhibits a maximum external quantum efficiency (EQE) of 2.1 % with a Commission International de L′Éclairage (CIE) coordinate of (0.70, 0.29). Moreover, an extremely high EQE of nearly 10 % with an emission band at λ=668 nm has been achieved in the doped device, which is comparable to the most-efficient deep-red/NIR phosphorescent OLEDs with similar electroluminescent spectra.
Co-reporter:Shipan Wang;Xianju Yan;Zong Cheng;Dr. Hongyu Zhang;Dr. Yu Liu ;Dr. Yue Wang
Angewandte Chemie 2015 Volume 127( Issue 44) pp:13260-13264
Publication Date(Web):
DOI:10.1002/ange.201506687
Abstract
Significant efforts have been made to develop high-efficiency organic light-emitting diodes (OLEDs) employing thermally activated delayed fluorescence (TADF) emitters with blue, green, yellow, and orange–red colors. However, efficient TADF materials with colors ranging from red, to deep-red, to near-infrared (NIR) have been rarely reported owing to the difficulty in molecular design. Herein, we report the first NIR TADF molecule TPA-DCPP (TPA=triphenylamine; DCPP=2,3-dicyanopyrazino phenanthrene) which has a small singlet–triplet splitting (ΔEST) of 0.13 eV. Its nondoped OLED device exhibits a maximum external quantum efficiency (EQE) of 2.1 % with a Commission International de L′Éclairage (CIE) coordinate of (0.70, 0.29). Moreover, an extremely high EQE of nearly 10 % with an emission band at λ=668 nm has been achieved in the doped device, which is comparable to the most-efficient deep-red/NIR phosphorescent OLEDs with similar electroluminescent spectra.
Co-reporter:Kai Wang;Hongyu Zhang;Shanyong Chen;Guochun Yang;Jibo Zhang;Wenjing Tian;Zhongmin Su
Advanced Materials 2014 Volume 26( Issue 35) pp:6168-6173
Publication Date(Web):
DOI:10.1002/adma.201401114
Co-reporter:Guomeng Li;Dongxia Zhu;Tai Peng;Yu Liu;Martin R. Bryce
Advanced Functional Materials 2014 Volume 24( Issue 47) pp:7420-7426
Publication Date(Web):
DOI:10.1002/adfm.201402177
Two phosphorescent iridium complexes with bipolar transporting ability, namely FPPCA (500 nm) and BZQPG (600 nm), are synthesized and employed as an ideal host-guest system for phosphorescent organic light emitting diodes (PHOLEDs).The devices give very high-efficiency orange-red emission from BZQPG with maximum external quantum efficiency (EQE or ηext) of >27% and maximum power efficiency (PE or ηp) of >75 lm/W, and maintain high levels of 26% and 55 lm/W, 25% and 40 lm/W at high luminance of 1000 and 5000 cd m−2, respectively, within a range of 8–15 wt% of BZQPG. The realization of such high and stable EL performance results from the coexistence of two parallel paths: i) effective energy transfer from host (FPPCA) to guest (BZQPG) and ii) direct exciton formation on the BZQPG emitter, which can alternately dominate the electrophosphorescent emission. This all-phosphor doping system removes the charge-injection barrier from the charge-transport process to the emissive layer (EML) due to the inherent narrow Eg of both phosphors. Therefore, this ideal host–guest system represents a new design to produce PHOLEDs with high efficiency and low efficiency roll-off using a simple device configuration.
Co-reporter:Xiao Cheng, Shuheng Sun, Youchun Chen, Yajun Gao, Lin Ai, Tao Jia, Fenghong Li and Yue Wang
Journal of Materials Chemistry A 2014 vol. 2(Issue 31) pp:12484-12491
Publication Date(Web):23 May 2014
DOI:10.1039/C4TA01586J
A novel organic small molecule water-soluble poly-N-alkylpyridine substitued metallophthalocyanine derivative VOPc(OPyCH3I)8, namely 2,3,9,10,16,17,23,24-octakis-[N-methyl-(3-pyridyloxy)] vanadylphthalocyanine iodide (1:8), was synthesized and applied in polymer solar cells (PSCs). Notably, a power conversion efficiency (PCE) of 8.12% for the working area of 2 × 2 mm2 and a PCE of 7.23% for the working area of 4 × 4 mm2 have been achieved in the PSCs with this molecule as a cathode interlayer. They are comparable with the higher values of PCE of the PSCs reported currently, indicating that VOPc(OPyCH3I)8 is a new promising candidate as a good cathode interlayer for highly efficient PSCs.
Co-reporter:Kai Wang, Shipan Wang, Jinbei Wei, Shanyong Chen, Dong Liu, Yu Liu and Yue Wang
Journal of Materials Chemistry A 2014 vol. 2(Issue 33) pp:6817-6826
Publication Date(Web):30 Jun 2014
DOI:10.1039/C4TC00749B
In this work, two novel hybrids of an electron-accepting phosphine oxide moiety attached to a phenanthroimidazole have been designed and synthesized. The PO group is used as a point of saturation between the PPI moiety and the outer phenyl groups, so the high triplet energy of PPI is preserved to act as a host for red and green phosphorescent dopants. The strong intermolecular interactions and steric effect of the diphenylphosphine oxide (DPO) moiety endows the films with high quantum yields in the deep-blue emission region. Compared to PPI, the carrier (hole- and electron-)injection/transport properties were greatly promoted by the appended DPO group according to single-carrier device measurement. Besides, the morphological and thermal stabilities were also improved. The multiple functions enable adaptation of several simplified device configurations. The undoped deep-blue fluorescent device exhibits an external quantum efficiency of 2.24% with CIE (0.16, 0.08), very close to the NTSC blue standard CIE (0.14, 0.08). High performance for green (65.4 cd A−1, 73.3 lm W−1 and 18.0%) and red (19.0 cd A−1, 21.3 lm W−1 and 13.5%) phosphorescent devices used as hosts have been achieved. The experimental and theoretical relationships between the molecular structures and the optoelectronic properties are discussed.
Co-reporter:Iqbal Javed, Ayub Khurshid, Muhammad Nadeem Arshad and Yue Wang
New Journal of Chemistry 2014 vol. 38(Issue 2) pp:752-761
Publication Date(Web):27 Nov 2013
DOI:10.1039/C3NJ00477E
Quinacridone diimines 1–10 were synthesized by the condensation of anilines with alkyl substituted quinacridones (QA). Photophysical and electrochemical properties of the compounds were investigated. Unconventional behavior of absorption spectra suggested a decrease in π_conjugation within the QA skeleton as well as lack of extended π_conjugation between the QA skeleton and the N-phenyl rings. A computational study of compounds 1–10, a variable temperature 1H NMR study of compounds 2, 7 and 10 (for instance), and single crystal X-ray analysis of 2, 3, 6, 7, 8 and 10 indicated that the anomalous behavior is due to the buckled, non-planar structure of the quinacridones. Moreover the molecules existed in two interconvertible geometric isomeric forms at different temperatures. Molecular orbital calculations were performed at B3LYP/6-31+G(d), B3PW91/6-31G(d) and PBEPBE/6-31G(d) levels of theory at B3PW91/6-31G(d) optimized structures for both isomers of all compounds (1–10); the results obtained are in close agreement with the experimentally determined values.
Co-reporter:Kai Wang, Shipan Wang, Jinbei Wei, Yang Miao, Yu Liu, Yue Wang
Organic Electronics 2014 Volume 15(Issue 11) pp:3211-3220
Publication Date(Web):November 2014
DOI:10.1016/j.orgel.2014.08.062
•Two novel bipolar host materials containing phenanthroimidazole and dimesitylborane are obtained.•High-performance green, yellow and red PhOLEDs based on two bipolar hosts have been demonstrated.•Very high and stable EL efficiencies are achieved.In this work, two novel bipolar host materials p-BPPI and m-BPPI containing phenanthroimidazole/dimesitylborane (Mes2B) with para- and meta-linkage have been designed, synthesized and characterized. The appending Mes2B moiety improves the thermal stability, electrochemical stability and carrier injection/transport ability of both target compounds. The test results of time-of-flight (TOF) and single-carrier devices show that both the new hosts possess bipolar charge-transporting characteristics. As a result, series of highly efficient green (66.3 cd A−1, 63.1 lm W−1, 18.2%), yellow (55.2 cd A−1, 66.6 lm W−1, 14.5%) and red (20.1 cd A−1, 20.4 lm W−1, 13.5%) PhOLEDs are achieved by using them as the universal host materials. The results indicate that bipolar host p-BPPI and m-BPPI have high potential in fabricating various color OLEDs for displays and lighting applications. Our study further enriches the selection of D and A group for phosphorescent host materials. The relationship between molecular structures and optoelectronic properties is discussed experimentally and theoretically.Two novel bipolar hosts containing phenanthroimidazole and dimesitylborane with para- and meta-linkage have been designed, synthesized and characterized. The appending Mes2B moiety improves the thermal stability, electrochemical stability and carrier injection/transport ability. Within these merit, we have fabricated highly efficient green (66.3 cd A−1, 63.1 lm W−1, 18.2%), yellow (55.2 cd A−1, 66.6 lm W−1, 14.5%) and red (20.1 cd A−1, 20.4 lm W−1, 13.5%) PhOLEDs by using these compounds as host materials. The results indicate that bipolar host p-BPPI and m-BPPI have high potential in fabricating various color OLEDs for displays and lighting applications.
Co-reporter:Di Li, Hongyu Zhang and Yue Wang
Chemical Society Reviews 2013 vol. 42(Issue 21) pp:8416-8433
Publication Date(Web):30 Jul 2013
DOI:10.1039/C3CS60170F
Four-coordinate organoboron compounds with rigid π-conjugated structures are intensely luminescent and have high carrier mobility which enables them to be applied in optoelectronics including organic light-emitting diodes (OLEDs), organic field-effect transistors, as well as photoresponsive, sensory and imaging materials. Various chelate ligands and boron moieties have been explored to construct proper electronic structures and suitable molecular arrangements, which play important roles on the photophysical and electronic properties of the four coordinate boron compounds. These efforts have produced a number of fascinating molecules, some of which have exhibited high performance as light emitting materials. In this article, we provide an overview of the progress in the molecular construction of four-coordinate organoboron compounds with an emphasis on their applications in OLEDs.
Co-reporter:Kai Wang;Fangchao Zhao;Chenguang Wang;Shanyong Chen;Dong Chen;Hongyu Zhang;Yu Liu;Dongge Ma
Advanced Functional Materials 2013 Volume 23( Issue 21) pp:2672-2680
Publication Date(Web):
DOI:10.1002/adfm.201202981
Abstract
Two coordination complex emitters as well as host materials Be(PPI)2 and Zn(PPI)2 (PPI = 2-(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenol) are designed, synthesized, and characterized. The incorporation of the metal atom leads to a twisted conformation and rigid molecular structure, which improve the thermal stability of Be(PPI)2 and Zn(PPI)2 with high Td and Tg at around 475 and 217 °C, respectively. The introduction of the electron-donating phenol group results in the emission color shifting to the deep-blue region and the emission maximum appears at around 429 nm. This molecular design strategy ensures that the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) HOMO and LUMO of Be(PPI)2 and Zn(PPI)2 localize on the different moieties of the molecules. Therefore, the two complexes have an ambipolar transport property and a small singlet–triplet splitting of 0.35 eV for Be(PPI)2 and 0.21 eV for Zn(PPI)2. An undoped deep-blue fluorescent organic light-emitting device (OLED) that uses Be(PPI)2 as emitter exhibits a maximum power efficiency of 2.5 lm W−1 with the CIE coordinates of (0.15, 0.09), which are very close to the National Television Standards Committee (NTSC) blue standard (CIE: 0.14, 0.08). Green and red phosphorescent OLEDs (PhOLEDs) that use Be(PPI)2 and Zn(PPI)2 as host materials show high performance. Highest power efficiencies of 67.5 lm W−1 for green PhOLEDs and 21.7 lm W−1 for red PhOLEDs are achieved. In addition, the Be(PPI)2-based devices show low-efficiency roll-off behavior, which is attributed to the more balanced carrier-transport property of Be(PPI)2.
Co-reporter:Shanyong Chen, Jinbei Wei, Kai Wang, Chenguang Wang, Dong Chen, Yu Liu and Yue Wang
Journal of Materials Chemistry A 2013 vol. 1(Issue 40) pp:6594-6602
Publication Date(Web):09 Aug 2013
DOI:10.1039/C3TC31271B
Two new indolo[3,2-b]carbazole derivatives (DPDT-ICZ and DNDT-ICZ) with multifunctionality were designed and synthesized. They were employed as deep-blue emitters, hole-transporting materials and hosts to fabricate organic light-emitting devices (OLEDs). The devices which used them as emitters displayed deep-blue emissions with CIE coordinates of (0.15, 0.08). They have been employed as hole-transporting and host material simultaneously to construct high performance yellow and red phosphorescent OLEDs. High power efficiencies (78.3 lm W−1 for yellow devices and 20.4 lm W−1 for red devices) for phosphorescent OLEDs were achieved. Importantly, these devices displayed the feature of low roll-off of efficiencies. At the luminance of 1000 cd m−2, roll-off of current efficiencies was 1.3% for the yellow device and 14.6% for the red device.
Co-reporter:Chenguang Wang, Dong Chen, Weiping Chen, Shanyong Chen, Kaiqi Ye, Hongyu Zhang, Jingying Zhang and Yue Wang
Journal of Materials Chemistry A 2013 vol. 1(Issue 35) pp:5548-5556
Publication Date(Web):08 Jul 2013
DOI:10.1039/C3TC30803K
The structures and properties of an indole-ring-fused quinacridone derivative 5,8,15,18-tetraoctyl-5,8,15,18-tetrahydroindolo[3,2-a]indole[3′,2′:5,6]quinacridone (IDQA), which was synthesized by an improved procedure, have been carefully investigated and compared with its parent compound N,N′-di(n-octyl)quinacridone (C8-QA). Concentration-dependent 1H NMR spectra revealed that the strong aggregations of IDQA existed in solution because of the flat and extended π-conjugation. Two polymorphs of IDQA with and without π⋯π interactions exhibited red and non emissions, respectively. One-dimensional micromaterials with different morphologies constructed by IDQA molecules were fabricated by a reprecipitation approach and they displayed different emission properties due to the different molecular packing. The nine-ring fused flat skeleton endowed this material with several elegant properties, including a high photoluminescent quantum yield in solution, and a high thermal and electrochemical stability. Therefore, the efficient doped organic light emitting device (OLED) with IDQA as the emitter was fabricated. Moreover, the large π-conjugation system endowed the IDQA thin film with ordered molecular packing and good hole transport properties (hole mobility μh = 0.047 cm2 V−1 s−1).
Co-reporter:Tai Peng, Guomeng Li, Kaiqi Ye, Chenguang Wang, Shanshan Zhao, Yu Liu, Zhaomin Hou and Yue Wang
Journal of Materials Chemistry A 2013 vol. 1(Issue 16) pp:2920-2926
Publication Date(Web):27 Feb 2013
DOI:10.1039/C3TC00500C
A bipolar iridium complex, (ppy)2Ir(dipig), based on the ancillary ligand N,N′-diisopropyl-diisopropyl-guanidinate (dipig) with well-known cyclometalated (C^N) ligand ortho-(2-pyridyl)phenyl (ppy), is applicable in phosphorescent organic light-emitting diodes (PHOLEDs) as an efficient emitter, using easily available host materials and a simple device fabrication process. The corresponding PHOLEDs are dominated by an efficient direct-exciton-formation mechanism and show very high EL efficiency together with gratifying host- and doping-concentration-independent features. EL efficiency values of more than 93 lm W−1 for power efficiency (ηp) and 24% for external quantum efficiency (ηext) accompanied by little efficiency roll-off at high luminance are achieved in the (ppy)2Ir(dipig)-based devices by adopting the common materials 4,4′-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (NPB) and 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBI) as the host, with rather random concentration ranges of 8–15 wt% and 15–30 wt%, respectively. To the best of our knowledge, these values are the highest efficiencies ever reported for yellow PHOLEDs, and are even comparable with the highest levels for PHOLEDs in the scientific literature. Moreover, the ηp and ηext values of the non-doped device can reach 70 lm W−1 and 18% respectively. They are almost two times higher than those of the most efficient reported PHOLEDs based on a neat emitting layer (EML).
Co-reporter:Chenguang Wang, Kai Wang, Qiang Fu, Jingying Zhang, Dongge Ma and Yue Wang
Journal of Materials Chemistry A 2013 vol. 1(Issue 3) pp:410-413
Publication Date(Web):20 Nov 2012
DOI:10.1039/C2TC00419D
Pentaphenylphenyl substituted quinacridone (QA) derivative BPP–QA with two propeller-like substituted groups was synthesized and showed intense emission in both solution and solid state.
Co-reporter:Di Li, Hongyu Zhang, Chenguang Wang, Shuo Huang, Jianhua Guo and Yue Wang
Journal of Materials Chemistry A 2012 vol. 22(Issue 10) pp:4319-4328
Publication Date(Web):16 Dec 2011
DOI:10.1039/C1JM14606H
2-(2′-Hydroxyphenyl)benzoxazole (HBO) and 2-(2′-hydroxyphenyl)benzothiazole (HBT) reacted with triphenylborane produced two rigid π-conjugated fluorescent cores 1 (BPh2(BOZ), BOZ = 2-(benzo[d]oxazol-2-yl)phenol) and 2 (BPh2(BTZ), BTZ = 2-(benzo[d]thiazol-2-yl)phenol). Comparisons of photophysical properties and calculations between para- and meta-diphenylamine-substituted derivatives 5 (BPh2(para-NPh2-BTZ)) and 7 (BPh2(meta-NPh2-BTZ)) demonstrated that functionalization at the para-position of the rigid core is effective in tuning the electronic structure and hence the photophysical properties of this type of boron-chelate complex. Simple modification of these frameworks by introducing various amine groups at the para-position allows the synthesis of strongly fluorescent materials 3 (BPh2(para-Cz-BTZ), Cz = 9H-carbazol-9-yl), 4 (BPh2(para-NPh2-BOZ), NPh2 = diphenylamino), 5, and 6 (BPh2(para-NMe2-BTZ), NMe2 = dimethylamino). The emission colors of these newly synthesized complexes together with the parent complexes 1 and 2 covered a wide range from deep blue to saturated red in both solution and the solid state. Crystal structure analysis discloses that two phenyl groups attached to the boron atom effectively keep the luminescent ring-fused π-conjugated skeletons apart, making these fluorophores highly emissive in solid forms (ΦF = 0.36–0.71). Organic light-emitting diodes employing these boron complexes as emitters not only keep the full-color tunable emission feature but also show high electroluminescent (EL) performance; for instance, the greenish-blue device based on 2 showed the highest efficiency of 7.8 cd A−1 and the yellow light-emitting device based on 4 exhibited the highest brightness (31220 cd m−2) among the boron-containing emitters reported so far.
Co-reporter:Tianlei Zhou, Tao Jia, Shanshan Zhao, Jianhua Guo, Hongyu Zhang, and Yue Wang
Crystal Growth & Design 2012 Volume 12(Issue 1) pp:179-184
Publication Date(Web):December 1, 2011
DOI:10.1021/cg200920d
The diversity of hydrogen and ionic bond interactions in 2,6-biphenyl-4-pyrone-acid (BPP–acid) supramolecular systems and the acid-induced luminescence character of BPP was reported. On the basis of X-ray single crystal structure analysis and theoretical calculation, the strong luminescence of BPP–HCl and BPP–TFA (TFA = trifluoroacetic acid) crystals was attributed to the protonation or strong hydrogen bond interactions between the carbonyl group of BPP and the proton of HCl or TFA. Notably, in BPP–TFA crystal the interaction between BPP and TFA displayed a “mixed bond” feature; namely, the bond between carbonyl of BPP and hydroxyl of TFA possesses partial hydrogen bond and partial ionic bond nature. The acid stimuli-luminescence properties of BPP film may offer a potential application in chemical sensors.
Co-reporter:Shanshan Zhao, Fei Yu, Guochun Yang, Hongyu Zhang, Zhongmin Su and Yue Wang
Dalton Transactions 2012 vol. 41(Issue 24) pp:7272-7277
Publication Date(Web):20 Apr 2012
DOI:10.1039/C2DT00009A
To deeply understand the charge-transporting nature of Pt(CNtBu)2(CN)2 nanowires induced by intermolecular Pt⋯Pt interactions, calculations based on first-principle band structure and Marcus theory have been performed. The calculated bandwidths of the valence band, conducting band, and the effective masses of hole and electron are almost equal. This suggests that this complex has ambipolar transport characteristics, in agreement with experimental results. Density of states analysis revealed that the hole transport resulted mainly from the Pt⋯Pt interactions, while the electron transport was derived mainly from the CN groups. The character of the frontier molecular orbitals, reorganization energies and transfer integrals in different directions also supports the calculated first-principle band structure. Moreover, an investigation into the intermolecular interaction energy of neighbors revealed that there is a remarkable relationship between the intermolecular interaction energy and the transfer integral.
Co-reporter:Chenguang Wang, Weiping Chen, Shanyong Chen, Shanshan Zhao, Jingying Zhang, Dengli Qiu and Yue Wang
New Journal of Chemistry 2012 vol. 36(Issue 9) pp:1788-1797
Publication Date(Web):13 Jun 2012
DOI:10.1039/C2NJ40306D
A series of regioregular head-to-tail oligo(3-hexylthiophene)-functionalized dicyano-ethylene substituted quinacridone derivatives DCN-Tn-QA (n = 1–3) were designed and synthesized. These linear π-conjugated donor–acceptor–donor (D–A–D) molecules with different length of the oligothiophene chain have been achieved in good yields via iterative iodination and Suzuki cross-coupling reactions followed by Knoevenagel condensations. Their photophysical and electrochemical properties, as well as density functional theory (DFT) calculations, were systematically investigated. The compounds of DCN-Tn-QA (n = 1–3) with an intense absorption range from 350–750 nm, suitable LUMO levels at around −4.0 eV and considerable film formation properties, were suitable for application in organic solar cells (OSCs) as acceptors. The organic bulk heterojunction (BHJ) solar cell based on the blend film of P3HT/DCN-T2-QA (1:1, w/w) (P3HT = poly(3-hexylthiophene)) showed a power conversion efficiency (PCE) of 0.51% under the illumination of AM.1.5, 100 mW cm−2. Compared with P3HT/PCBM (PCBM = [6,6]-phenyl-C61-butyric acid methyl ester), the blend film of P3HT/DCN-T2-QA displayed a stronger response to the solar spectrum in the long wavelength range from 665–750 nm.
Co-reporter:Xiaoyue Mu, Dong Liu, Xiao Cheng, Lu Li, Hongyu Zhang, Yue Wang
Organic Electronics 2012 Volume 13(Issue 3) pp:457-463
Publication Date(Web):March 2012
DOI:10.1016/j.orgel.2011.11.013
Organic semiconducting microwires can be self-assembled from a trinuclear gold(I) complex Au3I(MeNCOMe)3 (Au3A3) based on extended intermolecular AuI⋯AuI interactions by a simple solution method. High mobility (0.23 cm2 V−1 s−1) of the microwires measured in ambient conditions by organic field-effect transistor (OFET) devices was achieved, vapor and photo responsive conductive characteristics with great sensibility, reversibility and rapid response were also revealed. The AuI⋯AuI interaction based structure of the Au3A3 microwires can broaden the scope of nano- and micro-scale organic semiconductors and will be valuable for the future design and synthesis of new organic semiconducting materials and also have potential in the fields of chemo-sensing and photo detectors.Graphical abstractHighlights► Au3A3 microwires were assembled based on intermolecular AuI⋯AuI interactions. ► We fabricated organic field-effect transistor (OFET) devices with the wires. ► The microwires devices exhibited high hole mobility (0.23 cm2 V−1 s−1). ► The microwires showed vapor-/photo-switchable conductive characteristics.
Co-reporter:Chenguang Wang, Shanyong Chen, Kai Wang, Shanshan Zhao, Jingying Zhang, and Yue Wang
The Journal of Physical Chemistry C 2012 Volume 116(Issue 33) pp:17796-17806
Publication Date(Web):August 2, 2012
DOI:10.1021/jp305187m
A series of π-conjugated dendrimers Cn-QA and Tn-QA (n = 1–3) composed of quinacridone core and carbazole dendrons have been designed and synthesized. These dumbbell-like dendrimers with carbazole dendrons from first to third generation were achieved by convergent synthetic strategy. Their 1H NMR spectra, electrochemical, photophysical properties, and film formation behaviors as well as aggregation structures in solid states have been fully investigated. The relationships between the structures and properties of dendrimers have been established. The electron-withdrawing substituent effects and the limited conjugations of the carbazole dendrons have been studied. Compared with the parent molecule N,N′-di(n-butyl)quinacridone (DBQA), the HOMO levels of the dendrimers increased and the LUMO levels decreased due to the carbazole dendrons substitution. The absorptions and emissions of dendrimers displayed red-shift feature compared with that of DBQA, while the higher generation dendrimer displayed slightly blue-shift tendency compared with the lower one. The aggregation structures of films and solid powder samples could be efficiently modulated by the carbazole dendrons and tert-butyl groups. In particular, dendrimers C2-QA and C3-QA exhibited piezochromic luminescence phenomenon, and the mechanism was preliminarily investigated.
Co-reporter:Iqbal Javed, Tianlei Zhou, Faheem Muhammad, Jianhua Guo, Hongyu Zhang, and Yue Wang
Langmuir 2012 Volume 28(Issue 2) pp:1439-1446
Publication Date(Web):December 7, 2011
DOI:10.1021/la202755z
A new series of acceptor–donor–acceptor (A–D–A) type quinoacridine derivatives (1–3) with aggregation-induced red emission properties were designed and synthesized. In these compounds, the electron-withdrawing 2-(3,5-bis(trifluoromethyl)phenyl)acetonitrile groups act as electron-accepting units, while the alkyl-substituted conjugated core acts as electron-donating units. The restriction of intramolecular rotation was responsible for the AIE behavior of compounds 1–3. All compounds were employed as building blocks to fabricate one-dimensional (1-D) organic luminescent nano- or microwires based on reprecipitation or slow evaporation approaches. Morphological transition from zero-dimensional (0-D) hollow nanospheres to 1-D nanotubes has been observed by recording SEM and TEM images of aggregated sates of compound 2 in THF/H2O mixtures at different aging time. It was demonstrated that the synthesized compounds with different lengths of alkyl chains displayed different wire formation properties. The single-crystal X-ray analysis of compound 2 provided reasonable explanation for the formation of 1-D nano- or microstructures.
Co-reporter:Dandan Yao, Shanshan Zhao, Jianhua Guo, Zuolun Zhang, Hongyu Zhang, Yu Liu and Yue Wang
Journal of Materials Chemistry A 2011 vol. 21(Issue 11) pp:3568-3570
Publication Date(Web):09 Feb 2011
DOI:10.1039/C1JM00009H
Two sets of hydroxyphenyl-benzothiazole based compounds, which exhibited emission colors across the entire visible spectrum for both photoluminescence and electroluminescence, have been designed and synthesized.
Co-reporter:Tai Peng, Yu Yang, Hai Bi, Yu Liu, Zhaomin Hou and Yue Wang
Journal of Materials Chemistry A 2011 vol. 21(Issue 11) pp:3551-3553
Publication Date(Web):19 Jan 2011
DOI:10.1039/C0JM03645E
A high-efficiency and pure white OLED has been realized by only doping one novel phosphorescent orange-light-emitting complex (bzq)2Ir(dipba) into a suitable deep-blue-emitting fluorescent complex Bepp2 as an emissive layer. The highest efficiency for white OLEDs with a simple HTL-EML-ETL architecture, with a peak power efficiency (PE) of 48.8 lm W−1 and a peak external quantum efficiency (EQE) of 27.8%, has been realized by employing both singlet and triplet excitons for emission. The PE and EQE at the applicable brightness of 1000 cd m−2 are 37.5 lm W−1 and 36.8%, respectively.
Co-reporter:Tai Peng, Yu Yang, Yu Liu, Dongge Ma, Zhaomin Hou and Yue Wang
Chemical Communications 2011 vol. 47(Issue 11) pp:3150-3152
Publication Date(Web):27 Jan 2011
DOI:10.1039/C0CC04684A
A phosphorescent material (Fppy)2Ir(dipba) possessing high PL efficiency in the solid state and superior hole/electron transporting property has acted successfully as an efficient neat phosphorescent emitter as well as an excellent host for high-performance PHOLEDs.
Co-reporter:Zuolun Zhang, Dandan Yao, Tianlei Zhou, Hongyu Zhang and Yue Wang
Chemical Communications 2011 vol. 47(Issue 27) pp:7782-7784
Publication Date(Web):14 Jun 2011
DOI:10.1039/C1CC11882J
Crystalline samples of 3(5)-(9-anthryl)pyrazole and its one derivative exhibit interesting piezochromic behaviors with the emission colors differently changing from blue to green and from green to blue, respectively, upon grinding.
Co-reporter:Hai Bi, Dong Chen, Di Li, Yang Yuan, Dandan Xia, Zuolun Zhang, Hongyu Zhang and Yue Wang
Chemical Communications 2011 vol. 47(Issue 14) pp:4135-4137
Publication Date(Web):07 Mar 2011
DOI:10.1039/C1CC00060H
A novel green emissive Alq3 solid with a facial isomeric form has been obtained by grinding the typical blue luminescent fac-Alq3 crystalline powder. This is the first report, to the best of our knowledge, that a fac-Alq3 isomer emits green light.
Co-reporter:Tai Peng, Guofang Li, Yu Liu, Yu Yang, Ling Wang, Ying Wu, Yue Wang
Organic Electronics 2011 Volume 12(Issue 11) pp:1783-1787
Publication Date(Web):November 2011
DOI:10.1016/j.orgel.2011.07.010
Co-reporter:Tai Peng, Kaiqi Ye, Yu Liu, Ling Wang, Ying Wu, Yue Wang
Organic Electronics 2011 Volume 12(Issue 11) pp:1914-1919
Publication Date(Web):November 2011
DOI:10.1016/j.orgel.2011.08.006
Efficient blue organic light-emitting diodes have been developed based on one novel fluorescent beryllium complex bis(2-(2-hydroxyphenyl)-4-methyl-pyridine)beryllium (Be(4-mpp)2). The simple double-layer device based on Be(4-mpp)2 as the EML as well as the ETL not only shows pure and stable blue emission with the CIE coordinates of (0.14, 0.09), but also presents very high EL efficiency in terms of both the peak values (5.4% for EQE and 4.2 lm W−1 for PE) and the EQE value remaining ⩾4.0% in very wide brightness range (10–10,000 cd m−2) that indicates very good operational stability. They are the highest EL efficiencies ever reported for such saturated and stable OLED (CIE: x < 0.15, y < 0.10) to the best of our knowledge.Graphical abstractEfficient blue organic light-emitting diodes have been developed based on one novel fluorescent beryllium complex bis(2-(2-hydroxyphenyl)-4-methyl-pyridine)beryllium (Be(4-mpp)2). The simple double-layer device based on Be(4-mpp)2 as the EML as well as the ETL not only shows pure and stable blue emission with the CIE coordinates of (0.14, 0.09), but also presents very high EL efficiency in terms of both the peak values (5.4% for EQE and 4.2 lm W−1 for PE) and the EQE value remaining ⩾4.0% in very wide the brightness range (10–10,000 cd m−2) that indicates very good operational stability. These values mentioned above are the highest EL efficiencies ever reported for such saturated deep-blue OLED to the best of our knowledge.Highlights► A novel fluorescent blue-emission complex Be(4-mpp)2 was developed. ► Be(4-mpp)2-based device exhibited deep-blue EL with the stable CIE (0.14, 0.09). ► The non-doped blue OLED showed very high EL efficiency of 5.4% and 4.2 lm W−1.
Co-reporter:Tai Peng, Guofang Li, Yu Liu, Ying Wu, Kaiqi Ye, Dandan Yao, Yang Yuan, Zhaomin Hou, Yue Wang
Organic Electronics 2011 Volume 12(Issue 6) pp:1068-1072
Publication Date(Web):June 2011
DOI:10.1016/j.orgel.2011.03.030
This paper reports series of highly efficient organic light-emitting diodes (OLEDs) with high-quality blue emission that employs an aromatic enyne derivative (E)-CPEY doped in the CBP (4, 4′-N, N′-dicarbazolylbiphenyl) host with the easily controlled doping concentrations as the emitters. The peak EL efficiencies (>8.5 cd A−1, >5.5 lm W−1 and ⩾6.0%) of these blue OLEDs with the stable CIE (0.15, 0.10 ± 0.01) are the highest values ever reported for the saturated deep-blue OLEDs up to now. Moreover, although the doping concentration of them changes such large span as 10–20 wt%, the deviation for both the EL efficiency and the brightness always keep within a very small range during almost the whole driving process, which should lead to the easy and reproducible fabrication process of high performance blue OLEDs.Graphical abstractHighly efficient blue OLEDs employing an aromatic enyne derivative (E)-CPEY doped in the CBP host with the easily controlled doping concentrations as the emitters, are developed. The resulting EL devices with the pure and stable blue light (0.15, 0.10 ± 0.01) not only show relatively insensitive EL performances to the doping concentration changing in a high and wide range of 10 (for device II)-20 (for device III) wt%, but also exhibit the highest EL efficiencies (>8.5 cd A−1, >5.5 lm W−1 and ⩾6.0%) ever reported for the saturated deep-blue OLEDs up to now.Highlights► OLEDs based on aromatic enyne compound exhibit pure blue emission. ► The blue OLEDs show high EL efficiency in wide doping-concentration range. ► The highest EL efficiency ever reported for the saturated deep-blue OLEDs are presented.
Co-reporter:Yu Yang, Tai Peng, Kaiqi Ye, Ying Wu, Yu Liu, Yue Wang
Organic Electronics 2011 Volume 12(Issue 1) pp:29-33
Publication Date(Web):January 2011
DOI:10.1016/j.orgel.2010.10.006
This paper reports a highly efficient organic light-emitting diode (OLED) with high-quality white emission that employs a deep blue-emitting beryllium complex bis(2-(2-hydroxyphenyl)-pyridine)beryllium (Bepp2) doped with a wide-bandwidth orange-emitting fluorescent dye 4-(dicyanomethylene)-2-methyl-6-(4-dimethylaminostyryl)-4-H-pyran (DCM) through incomplete energy transfer from the blue host to the orange dopant. The two-component WOLED exhibits ideal and stable CIE coordinates (0.334 ± 0.002, 0.337 ± 0.007) with a high color rendering index equal to 79–81 upon variation in brightness from 10 to 10,000 cd m−2. As an all-fluorophore-doped white OLED, it yields very high EL efficiencies with the peak luminescence efficiency. The peak value of luminescence efficiency (LE), power efficiency (PE), and external quantum efficiency (EQE) is 14.0 ± 0.35 cd A−1, 9.2 ± 0.25 lm W−1, and 5.6 ± 0.15%, respectively.Graphical abstractResearch highlights► WOLED uses two commercial fluorescent materials as the emitting materials. ► Two-component WOLED yields stable and ideal white CIE coordinates. ► All-fluorophore-doped WOLED presents very high EL performance (LE, PE and EQE).
Co-reporter:Yang Yuan, Di Li, Xueqiang Zhang, Xingjia Zhao, Yu Liu, Jingying Zhang and Yue Wang
New Journal of Chemistry 2011 vol. 35(Issue 7) pp:1534-1540
Publication Date(Web):20 May 2011
DOI:10.1039/C1NJ20072K
Four phenanthroimidazole derivatives (a: 1,2-diphenyl-1H-phenanthro[9,10-d]imidazole; b: 2-phenyl-1-p-tolyl-1H-phenanthro[9,10-d]imidazole; c: 1-phenyl-2-p-tolyl-1H-phenanthro[9,10-d]imidazole; d: 1,2-di-p-tolyl-1H-phenanthro[9,10-d]imidazole) were synthesized and their single crystal structures, photophysical, electrochemical and mobility properties were carefully studied. Taking advantage of the thermal stability and the hole transporting (HT) ability, the highly efficient Alq3-based organic light-emitting diodes (OLEDs) have been achieved by employing the compounds a–d as a functional layer between NPB (4,4-bis(N-(1-naphthyl)-N-phenylamino)biphenyl) and Alq3 (tris(8-hydroxyquinoline)aluminium) layers. For the device of [ITO/NPB/d/Alq3/LiF/Al], a maximum luminous efficiency (LE) of 8.1 cd A−1 was obtained with a maximum brightness of 65130 cd m−2, which exhibited much higher efficiency compared to the device with structure of [ITO/NPB/Alq3/LiF/Al]. The results demonstrated not only an alternative idea to design novel HT materials, but also a convenient way to improve the performance of the NPB/Alq3-based devices by introduction of a suitable organic buffer layer.
Co-reporter:Iqbal Javed, Zoulun Zhang, Tai Peng, Tianlei Zhou, Hongyu Zhang, Muhammad Issa Khan, Yu Liu, Yue Wang
Solar Energy Materials and Solar Cells 2011 95(9) pp: 2670-2676
Publication Date(Web):
DOI:10.1016/j.solmat.2011.05.040
Co-reporter:DingYi Yu;Tai Peng;Iqbal Javad;HongYu Zhang;JingYing Zhang
Science China Chemistry 2011 Volume 54( Issue 2) pp:314-319
Publication Date(Web):2011 February
DOI:10.1007/s11426-010-4194-6
Two novel quinacridone (QA) cyclophanes with intrinsic intramolecular dye-dye interactions have been designed and synthesized. X-ray crystal structures as well as detailed photophysical properties have been well demonstrated. These two dyes have a major advantage that efficient fluorescence quenching can be observed even in their dilute solutions. A comparison of photophysical properties between the dimeric QA cyclophane and its reference monomeric counterpart indicates that the dimerization is predominant for the fluorescence quenching of QA dyes in solution. This study provided some model QA derivatives with dimeric structures for understanding the fluorescence quenching of QA dyes in solutions.
Co-reporter:Chuandong Dou, Dong Chen, Javed Iqbal, Yang Yuan, Hongyu Zhang, and Yue Wang
Langmuir 2011 Volume 27(Issue 10) pp:6323-6329
Publication Date(Web):April 13, 2011
DOI:10.1021/la200382b
A trifluoromethyl-substituted benzothiadiazole-cored phenylene vinylene fluorophore (1) was synthesized and displayed piezo- and vapochromism and thermo-induced fluorescence variation in solid phase. Grinding could disrupt the crystalline compound 1 with orange emission into amorphous compound 1 with green emission, and heating treatment could change the amorphous compound 1 into crystalline compound 1. Ultraviolet−visible (UV−vis) absorption spectra, 13C nuclear magnetic resonance (NMR), and powder X-ray diffraction (PXRD) characterizations demonstrated that crystalline and amorphous compound 1 possess different molecular packing. A differential scanning calorimetry (DSC) measurement revealed that the emission switching was due to the exchange between the thermodynamic-stable crystalline and metastable amorphous states. The ground sample exhibited vapochromic fluorescence property. Furthermore, compound 1 showed interesting supramolecular assembly characteristics in solution. Slowly cooling the hot N,N-dimethylformamide (DMF) solution of compound 1 resulted in the formation of orange fluorescent fibers, whereas sonication treatment of the cooling solution led to the generation of organic molecular gel. The field emission scanning electronic microscope (FESEM) and fluorescent microscopy images revealed smooth nano- or microfiber and network morphology properties. The PXRD spectra confirmed that these nano- or microstructures had a similar molecular-packing model with the crystalline state of compound 1. Slow evaporation of the toluene solution of compound 1 could produce green emissive microrods, which exhibited interesting thermo-induced fluorescence variation.
Co-reporter:Chuandong Dou, Liang Han, Shanshan Zhao, Hongyu Zhang, and Yue Wang
The Journal of Physical Chemistry Letters 2011 Volume 2(Issue 6) pp:666-670
Publication Date(Web):March 3, 2011
DOI:10.1021/jz200140c
An electron donor−acceptor structured π-conjugated organic compound 1 composed of trifluoromethyl-biphenyl and cyano-stilbene-amine was designed and exhibited multi-stimuli-responsive fluorescence switching behaviors. The synthesized solid exhibited piezochromism in that grinding and heating could change the emission colors between orange-red and yellow. The amorphous 1 also showed interesting vapochromic behavior in that organic vapor could convert the yellow color into orange. The solution of 1 exhibited nearly no fluorescence at room temperature and intensive yellowish green emission at 77 K, while adding CF3COOH (TFA) resulted in green emissive state at room temperature and blue fluorescent state at 77 K.Keywords: aggregation; fluorescence; piezochromism; stimuli-responsive; vapochromism;
Co-reporter:ChuanDong Dou;Di Li;HongYu Zhang;HongZe Gao;JingYing Zhang
Science China Chemistry 2011 Volume 54( Issue 4) pp:
Publication Date(Web):2011 April
DOI:10.1007/s11426-011-4236-8
A series of cholesterol-appended quinacridone (QA) derivatives 1a–1d have been synthesized, in which 1b and 1c could form stable organogels in a wide range of organic solvents upon ultrasound irradiation. Field emission scanning electronic microscope (FESEM) and transmission electron microscopy (TEM) of xerogels or precipitates indicated that 1b and 1c formed 1D fibrous nanostructure, while 1a assembled into 3D flower-like microstructures. The ultrasound-induced organogel process was characterized by kinetic UV-vis and photoluminescence spectroscopic methods suggesting the formation of π-π aggregates in the gel state. Experimental results demonstrated that the ultrasound could promote molecules to contact frequently in the solution and induce semistable initial aggregates, which propagate to form nano/micro superstructures. The aggregation model was optimized by semiempirical AM1 calculation suggesting the hierarchical self-assembly process. In addition, the formed xerogel film exhibited mechanochromic property, and the phase transition process was accompanied by the fluorescence changes between yellowish green and orange.
Co-reporter:Hai Bi;Hongyu Zhang;Yu Zhang;Hongze Gao;Zhongmin Su
Advanced Materials 2010 Volume 22( Issue 14) pp:1631-1634
Publication Date(Web):
DOI:10.1002/adma.200903094
Co-reporter:Yu Zhang, Hongyu Zhang, Xiaoyue Mu, Siu-Wai Lai, Bin Xu, Wenjing Tian, Yue Wang and Chi-Ming Che
Chemical Communications 2010 vol. 46(Issue 41) pp:7727-7729
Publication Date(Web):20 Sep 2010
DOI:10.1039/C0CC02242J
The ordered [Pt(CN-tBu)2(CN)2] semiconducting microwires have been prepared on substrates based on solvent evaporation or dip–and–pull approaches and were found to display photo- and vapor-responsive conducting characteristics.
Co-reporter:Dingyi Yu, Tai Peng, Hongyu Zhang, Hai Bi, Jingying Zhang and Yue Wang
New Journal of Chemistry 2010 vol. 34(Issue 10) pp:2213-2219
Publication Date(Web):11 Jun 2010
DOI:10.1039/C0NJ00028K
A series of basket-shaped quinacridone (QA) cyclophanes 1–6 has been synthesized and characterized. Single-crystal X-ray analysis of 5 shows no infinite π–π aggregation between QA cores, reflecting a significant isolated effect of the bridging tethers. Photophysical properties have been carefully investigated. All cyclophanes show much higher quantum yields in concentrated solutions compared to the non-bridged QA analogue 7. Further application of 1 as a green dopant in EL devices exhibits current efficiencies of 11.2 and 7.2 cd A−1 with doping concentrations of 0.5 and 3 wt%, respectively. QA cyclophanes maintain a high luminescent yield in both concentrated solution and high doping concentration EL devices, verifying that the basket-shaped functionalization is an ideal strategy for depressing fluorescence quenching of QA dyes in the condensed phase.
Co-reporter:Hai Bi, Kaiqi Ye, Yunfeng Zhao, Yu Yang, Yu Liu, Yue Wang
Organic Electronics 2010 Volume 11(Issue 7) pp:1180-1184
Publication Date(Web):July 2010
DOI:10.1016/j.orgel.2010.04.015
Highly efficient organic light-emitting diode have been developed by using a fluorinated quinacridone derivative: N,N′-di(n-butyl)-2,9-difluoroquinacridone doped in Alq3 as the emitting layer. The device shows much lower driving-voltage (the turn-on voltage is 2.5 V, the practical brightness of 100 and 1000 cd m−2 are realized at 3.2 and 4.2 V, respectively) and higher power efficiency (the peak value of 15.2 lm W−1 is obtained at 4 V and 598 cd m−2) than that of devices based on all the other QA derivatives. The pronounced EL performance enhancement might be attributed to the improved electron injection induced by introducing the strong electron-withdrawing fluorine atoms into the QA derivative.
Co-reporter:Chuong Dou;Chenguang Wang;Dr. Hongyu Zhang;Dr. Hongze Gao ;Dr. Yue Wang
Chemistry - A European Journal 2010 Volume 16( Issue 35) pp:10744-10751
Publication Date(Web):
DOI:10.1002/chem.200903575
Abstract
In investigations into the effects of environmental factors on organogels, two urea-functionalized quinacridone derivatives 1 a and 1 b have been designed and synthesized. These two compounds can respond to ultrasound and thermal stimuli in the organic test solvents, and exhibit pronounced aggregation properties. The field-effect (FE)-SEM images of xerogels show the characteristic gelation morphologies of 3D fibrous network structures. The concentration- and temperature-dependent 1H NMR spectra suggest that the intermolecular π–π and hydrogen-bonding interactions of gelators are the main driving forces for the supramolecular assembly process. X-ray diffraction (XRD), UV/Vis absorption, and photoluminescent spectroscopy studies have been carried out and provide more information to define the molecular packing model in gelation states.
Co-reporter:Chuandong Dou, Di Li, Hongze Gao, Chunyu Wang, Hongyu Zhang and Yue Wang
Langmuir 2010 Volume 26(Issue 3) pp:2113-2118
Publication Date(Web):September 28, 2009
DOI:10.1021/la902663z
A series of monocholesterol substituted quinacridone derivatives MCCn (n = 4, 6, 8) has been designed and synthesized. Compounds MCC6 and MCC8 can gelate a wide range of organic solvents upon ultrasound irradiation and afford intriguing well-defined nanostructures composed of three-dimensional sponge-like superstructures or fibrous networks. Interestingly, the gel produced from MCC6 is sensitive to thermo-, aniline, and formic acid stimulus, giving obviously different aggregation behaviors as well as physical properties. Time-dependent spectroscopic data and theoretical calculation results provided explanation for the possible molecular aggregation mode during the formation of the gels.
Co-reporter:Yunfeng Zhao;Hongze Gao;Yan Fan;Tianlei Zhou;Zhongmin Su;Yu Liu
Advanced Materials 2009 Volume 21( Issue 31) pp:3165-3169
Publication Date(Web):
DOI:10.1002/adma.200803432
Co-reporter:Tianlei Zhou, Feng Li, Yan Fan, Weifeng Song, Xiaoyue Mu, Hongyu Zhang and Yue Wang
Chemical Communications 2009 (Issue 22) pp:3199-3201
Publication Date(Web):01 May 2009
DOI:10.1039/B900476A
A series of aminobenzoic acid crystals with stacking-induced emission properties has been achieved and the packing structures of the hydrogen-bonded acid dimers provided an explanation for the emission characteristics of the crystals.
Co-reporter:Zuolun Zhang, Hai Bi, Yu Zhang, Dandan Yao, Hongze Gao, Yan Fan, Hongyu Zhang, Yue Wang, Yanping Wang, Zhenyu Chen and Dongge Ma
Inorganic Chemistry 2009 Volume 48(Issue 15) pp:7230-7236
Publication Date(Web):June 25, 2009
DOI:10.1021/ic900673s
Four diboron-contained ladder-type π-conjugated compounds 1−4 were designed and synthesized. Their thermal, photophysical, electrochemical properties, as well as density functional theory calculations, were fully investigated. The single crystals of compounds 1 and 3 were grown, and their crystal structures were determined by X-ray diffraction analysis. Both compounds have a ladder-type π-conjugated framework. Compounds 1 and 2 possess high thermal stabilities, moderate solid-state fluorescence quantum yields, as well as stable redox properties, indicating that they are possible candidates for emitters and charge-transporting materials in electroluminescent (EL) devices. The double-layer device with the configuration of [ITO/NPB (40 nm)/1 or 2 (70 nm)/LiF (0.5 nm)/Al (200 nm)] exhibited good EL performance with the maximum brightness exceeding 8000 cd/m2.
Co-reporter:Yan Fan, Weifeng Song, Dingyi Yu, Kaiqi Ye, Jingying Zhang and Yue Wang
CrystEngComm 2009 vol. 11(Issue 8) pp:1716-1722
Publication Date(Web):21 May 2009
DOI:10.1039/B902129A
The crystallization of N,N-di(n-cetyl)quinacridone (DCQA) gives two crystalline polymorphs A and B. It is found that crystalline polymorphs A and B adopt remarkable different packing structures. The form A crystal is characterized by the strong intermolecular π⋯π interaction and C–H⋯O interaction. The form B crystal displays an intermolecular C–H⋯π interaction and hydrogen bonding interaction feature. In form B, every quinacridone core is sandwiched by two alkyl chains from two adjacent DCQA molecules. The photoluminescent (PL) spectra of two polymorphs in solution and in the solid state were reported. The PL spectra of DCQA in solution exhibit concentration-dependent property. The emission spectrum of form A displayed an obvious red shift compared to that of form B. The studies of the single-crystal structures and the solid-state emission spectra of the two polymorphs demonstrated that the molecular packing is the critical element determining the solid-state emission.
Co-reporter:Yan Fan, Yunfeng Zhao, Ling Ye, Bao Li, Guangdi Yang and Yue Wang
Crystal Growth & Design 2009 Volume 9(Issue 3) pp:1421
Publication Date(Web):January 20, 2009
DOI:10.1021/cg800785u
The single crystal X-ray structures of four polymorphs and two pseudopolymorphs of N,N-di(n-butyl)quinacridone (DBQA) are investigated. Polymorphs A, B, and C crystallize in monoclinic systems, and polymorph D, pseudopolymorphs E and F crystallize in triclinic systems. Four polymorphs and two pseudopolymorphs show different characteristics of molecular structures and packing arrangements. The six crystalline phases show slight differences in the quinacridone (QA) core structures and the orientations of the n-butyl chains. Noncovalent intermolecular interactions such as C−H···O hydrogen bonds and π···π stacking interactions are different for the six crystals. The emission properties of the polymorphs and pseudopolymorphs in the solid state have been reported. All the polymorphs and the pseudopolymorphs exhibit solid-state photoluminescence. The crystal phases with stronger π···π interactions show the emission maximum at a longer wavelength region, while that with relatively weaker π···π interactions exhibit an emission maximum at a shorter wavelength region. From the X-ray single-crystal analysis, we can conclude that the molecular packing structure is the critical element that determines the solid-state emission characteristics.
Co-reporter:Zuolun Zhang, Yu Zhang, Dandan Yao, Hai Bi, Iqbal Javed, Yan Fan, Hongyu Zhang and Yue Wang
Crystal Growth & Design 2009 Volume 9(Issue 12) pp:5069-5076
Publication Date(Web):November 9, 2009
DOI:10.1021/cg9008569
We have designed and synthesized a series of 9-anthrylpyrazole derivatives 1,4-bis(3-(9-anthryl)-1-pyrazolylmethyl)benzene (1), 1-(3-(9-anthryl)-1-pyrazolylmethyl)-4-(5-(9-anthryl)-1-pyrazolylmethyl)benzene (2), 1,4-bis(3-(9-anthryl)-1-pyrazolyl)benzene (3), and 1-(3-(9-anthryl)-1-pyrazolyl)-4-(5-(9-anthryl)-1-pyrazolyl)benzene (4). All compounds formed two types of crystals that exhibited anthracene-arrangement-dependent emission colors. For instance, crystal 1a with strong π-overlap between anthracene moieties exhibited an emission maximum at 515 nm, while 1b with no such interchromophore interactions displayed an emission band at 424 nm. The fluorescence quantum yield (ΦF) measurements showed that the blue-emitting crystals have high quantum yields (ΦF = 0.46 for 1b, 0.90 for 2a, 0.91 for 2b, 0.77 for 3b, and 0.51 for 4a), suggesting their potential as blue emitters in optoelectronics.
Co-reporter:Hongze Gao, Houyu Zhang, Rigen Mo, Shiling Sun, Zhong-Min Su, Yue Wang
Synthetic Metals 2009 Volume 159(17–18) pp:1767-1771
Publication Date(Web):September 2009
DOI:10.1016/j.synthmet.2009.05.023
Co-reporter:Yunfeng Zhao, Xiaoyue Mu, Chunxiao Bao, Yan Fan, Jingying Zhang and Yue Wang
Langmuir 2009 Volume 25(Issue 5) pp:3264-3270
Publication Date(Web):February 10, 2009
DOI:10.1021/la804182d
The fluorinated quinacridone derivatives N,N′-dialkyl-2,9-difluoroquinacridone (Cn-DFQA, n = 4, 8, 10, 16) with different alkyl chains were used as building blocks to assemble luminescent micromaterials. It was demonstrated that the morphology and emission of the Cn-DFQA-based micromaterials strongly depended on their alkyl chain length. C4-DFQA and C8-DFQA showed stronger tendency to form 1-D microstructures, while C10-DFQA and C16-DFQA displayed the aggregation properties to form diamond and hexagonal platelike microcrystals, respectively. The photoluminescent (PL) spectra of Cn-DFQA (n = 4, 8, 10, 16) in THF dilute solutions displayed approximate profiles with a sharp emission peak at 533 nm and a shoulder at 573 nm, while the PL spectra of the Cn-DFQA-based micromaterials exhibited obviously red-shift emission bands at 622 nm for C4-DFQA, 627 nm for C8-DFQA, 614 nm for C10-DFQA, and 613 nm for C16-DFQA, respectively. The single-crystal X-ray structures of four Cn-DFQA compounds have been studied. In the C4-DFQA and C8-DFQA single crystals, there are 1-D molecular columns based on the intermolecular π···π and hydrogen bonding interactions. In the single crystals of C10-DFQA and C16-DFQA, the molecules assembled into 2-D molecular sheets based on the hydrogen bonds and C−H···π interactions. The molecular packing structures provide a reasonable explanation for the alkyl chain length dependent morphologies and emission properties of fluorinated quinacridone micromaterials.
Co-reporter:Yunfeng Zhao;Yan Fan;Xiaoyue Mu;Hongze Gao;Jia Wang;Jingying Zhang
Nano Research 2009 Volume 2( Issue 6) pp:493-499
Publication Date(Web):2009 June
DOI:10.1007/s12274-009-9045-4
It is a great challenge to spontaneously assemble achiral molecules into twisted nanostructures in the absence of chiral substances. Here we show that two achiral centrosymmetric quinacridone (QA) derivatives, N,N′-di(n-hexyl)-1, 3, 8, 10-tetramethylquinacridone (C6TMQA) and N,N′-di(n-decyl)-1, 3, 8, 10-tetramethylquinac ridone (C10TMQA), can be employed as building blocks to fabricate well-defined twisted nanostructures by controlling the solvent composition and concentration. Bowknot-like bundles with twisted fiber arms were prepared from C6TMQA, whilst uniform twisted fibers were generated from C10TMQA in ethanol/THF solution. Spectroscopic characterization and molecular simulation calculations revealed that the introduction of ethanol into the solution could induce a staggered aggregation of C6TMQA (or C10TMQA) molecules and the formation of twisted nanostructures. Such twisted materials generated from achiral organic functional molecules may be valuable in the design and fabrication of new materials for optoelectronic applications.
Co-reporter:GuoLi Zhao;Yan Fan;Cheng Huo;Hang Bian;WeiFeng Song
Science Bulletin 2009 Volume 54( Issue 10) pp:1677-1684
Publication Date(Web):2009 May
DOI:10.1007/s11434-009-0062-1
The syntheses of three carbazyl-containing quinacridone derivatives, N,N′-di((N-carbazyl)-n-butyl) quinacridone (DCBQA), N,N′-di((N-carbazyl)-n-hexyl)quinacridone (DCHQA) and N,N′-di((N-carbazyl)-n-octyl)quinacridone (DCOQA), are reported, and the photoluminescent (PL) characteristics are presented. The single crystal X-ray structures of DCBQA, DCHQA and DCOQA are investigated. The crystal of DCBQA is characterized by intermolecular п•••п interactions between quinacridone cores and carbazole moieties resulting in the formation of DCBQA molecule layer, in which every quinacridone core is surrounded by four carbazole groups. In DCHQA crystal, molecules assemble into two kinds of oriented columns based on intermolecular п•••п interactions between quinacridone cores. The DCOQA crystal displays intermolecular CH•••п and hydrogen bonding interactions feature. In DCOQA solid, every quinacridone core is sandwiched by two alkyl chains from two adjacent DCOQA molecules and simultaneously linked together with two other quinacridone cores by hydrogen bonding interactions. The PL spectra of the three compounds in solution exhibit concentration-dependent properties and their PL quantum causes decrease with the increasing concentration.
Co-reporter:Yu Zhang, Zuolun Zhang, Yunfeng Zhao, Yan Fan, Tianjian Tong, Hongyu Zhang and Yue Wang
Langmuir 2009 Volume 25(Issue 11) pp:6045-6048
Publication Date(Web):May 5, 2009
DOI:10.1021/la901254j
Well-defined 1D microwires of CuPcOC4 with diameters of about 1.0 μm and lengths ranging from 260 to 300 μm as well as ultralong microwires (>5 mm) with diameters of about 10 μm and high length/diameter aspect ratios were synthesized via a simple solution process. Electrical conductive devices based on these microwires fabricated in situ on glass substrates with two ITO electrodes exhibited excellent conductivity properties.
Co-reporter:Junwei Ye, Jingying Zhang, Guiling Ning, Ge Tian, Yan Chen and Yue Wang
Crystal Growth & Design 2008 Volume 8(Issue 8) pp:3098
Publication Date(Web):July 15, 2008
DOI:10.1021/cg800310j
A series of lanthanide coordination polymers [Ln(NIPH)(HNIPH)(phen)] [Ln = Tb (1), Ho (2), Er (3), La (4), Sm (5)], [Ln2(NIPH)3(phen)2(H2O)]·(H2O) (Ln = Pr (6), Yb (7), [Ln2(NIPH)3(phen)2] [Ln = Eu (8), Nd (9)] (H2NIPH = 5-nitroisophthalic acid, phen = 1,10-phenanthroline) were hydrothermally synthesized and characterized by single-crystal X-ray diffraction. The frameworks constructed from dinuclear lanthanide building blocks exhibit three typical structure features: 1−3 possess one-dimensional double-stranded looplike chain structures, 4−7 have two-dimensional layer structure characteristics, 8 and 9 are the three-dimensional frameworks with pcu topology. In 1−9, NIPH ligands adopt multidentate coordination modes. The supramolecular architectures of 1−9 show that the presence of phen ligands and nitro groups on NIPH induced the formation of numerous hydrogen bonds. The luminescent and magnetic properties of 8 and 9 are investigated.
Co-reporter:Hongze Gao, Chunsheng Qin, Houyu Zhang, Shuixing Wu, Zhong-Min Su and Yue Wang
The Journal of Physical Chemistry A 2008 Volume 112(Issue 38) pp:9097-9103
Publication Date(Web):August 27, 2008
DOI:10.1021/jp804308e
The structural, electronic, and carrier transport properties of bathocuproine (BCP), which is a typical hole/exciton-blocking material applied in organic light-emitting diodes (OLEDs), have been investigated based on density functional theory (DFT) and ab initio HF method. The detail characterizations of frontier electronic structure and lowest-energy optical transitions have been studied by means of time-dependent density functional theory (TD-DFT). Five BCP analogues, o-phenanthroline (1), 2,9-dimethyl-1,10-phenanthroline (2), 2,9-diphenyl-1,10-phenanthroline (3), 4,7-diphenyl-1,10-phenanthroline (4), and 2,9-bis(trifluoromethyl)-1,10-phenanthroline (5) have also been studied in order to select more suitable candidates of efficient hole-blocking materials. The calculated results showed that rigid planar structures, conjugate degrees, and substitute groups play crucial roles in the hole/exciton-blocking and electron-transport properties of these materials. The calculated geometries, ionization energies (IP), and energy gap between the singlet ground state and triplet excited state (ET1) were well in agreement with the experimental results. On the basis of the incoherent transport model, the calculated electron mobility of BCP is 1.79 × 10−2 cm2/(V s), which is comparable to experimental results of 1.1 × 10−3 cm2/(V s). The electron mobilities for compounds 1, 4, and 5 are 3.45 × 10−2, 2.90 × 10−2, and 1.40 × 10−2 cm2/(V s), respectively. The calculated results indicated that compounds 1, 4, and 5 may be more effective hole/exciton-blocking materials than BCP.
Co-reporter:Yu DingYi;Zhao YunFeng;Zhang JingYing;Wang Yue
Science Bulletin 2008 Volume 53( Issue 11) pp:1651-1656
Publication Date(Web):2008 June
DOI:10.1007/s11434-008-0240-6
A novel Schiff-base-boron-quinacridone compound (4) has been synthesized. The absorption and emission properties of 4 have been studied carefully. Experimental results demonstrated that the introduction of Schiff-base-boron moieties could suppress the aggregation of molecules 4 in solution and enhance the photoluminescent efficiency in relatively high concentration solution. The energy transfer from the Schiff-base-boron moieties to quinacridone cores could take place in 4 system.
Co-reporter:Y.-S. Yao;Q.-X. Zhou;X.-S. Wang;Y. Wang;B.-W. Zhang
Advanced Functional Materials 2007 Volume 17(Issue 1) pp:
Publication Date(Web):23 NOV 2006
DOI:10.1002/adfm.200600055
2-(2-tert-Butyl-6-((E)-2-(2,6,6-trimethyl-2,4,5,6-tetrahydro-1H-pyrrolo[3,2,1-ij]quinolin-8-yl)vinyl)-4H-pyran-4-ylidene)malononitrile (DCQTB) is designed and synthesized in high yield for application as the red-light-emitting dopant in organic light-emitting diodes (OLEDs). Compared with 4-(dicyanomethylene)-2-tert-butyl-6-(1,1,7,7,-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB), one of the most efficient red-emitting dopants, DCQTB exhibits red-shifted fluorescence but blue-shifted absorption. The unique characteristics of DCQTB with respect to DCJTB are utilized to achieve a red OLED with improved color purity and luminous efficiency. As a result, the device that uses DCQTB as dopant, with the configuration: indium tin oxide (ITO)/N,N′-bis(1-naphthyl)-N,N′-diphenyl-1,1′-biphenyl-4,4′-diamine (NPB; 60 nm)/tris(8-quinolinolato) aluminum (Alq3):dopant (2.3 wt %) (7 nm)/2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP; 12 nm)/Alq3(45 nm)/LiF(0.3 nm):Al (300 nm), shows a larger maximum luminance (Lmax = 6021 cd m–2 at 17 V), higher maximum efficiency (ηmax = 4.41 cd A–1 at 11.5 V (235.5 cd m–2)), and better chromaticity coordinates (Commission Internationale de l'Eclairage, CIE, (x,y) = (0.65,0.35)) than a DCJTB-based device with the same structure (Lmax = 3453 cd m–2 at 15.5 V, ηmax = 3.01 cd A–1 at 10 V (17.69 cd m–2), and CIE (x,y) = (0.62,0.38)). The possible reasons for the red-shifted emission but blue-shifted absorption of DCQTB relative to DCJTB are also discussed.
Co-reporter:Jia Wang;ZuoLun Zhang;JunWei Ye;JingYing Zhang
Science Bulletin 2007 Volume 52( Issue 10) pp:1307-1310
Publication Date(Web):2007 May
DOI:10.1007/s11434-007-0200-6
The nanocrystals based on a polar organic compound INBP (4-iodo-4′-nitrobiphenyl) have been fabricated by reprecipitation approach. For the formation of INBP based nanocrystals, the intermolecular iodo⋯nitro interaction is the dominant driving force and the micelles formed by the surfactant CTAB (cetyltrimethylammonium bromide) molecules are the efficient templates for controlling morphologies of nanocrystals. The field emission scanning electro microscope (FESEM) images demonstrated that prism-like and needle-like nanocrystals of INBP were formed in pure water and micell containing aqueous solution, respectively. XRD pattern and UV/vis absorption spectra were employed to characterize the nanocrystals.
Co-reporter:H. Y. Zhang;Z. L. Zhang;K. Q. Ye;J. Y. Zhang;Y. Wang
Advanced Materials 2006 Volume 18(Issue 18) pp:2369-2372
Publication Date(Web):12 SEP 2006
DOI:10.1002/adma.200600704
3(5)-(9-Anthryl)pyrazole (ANP) can be used as a building block to construct different luminescent single crystals based on hydrogen bonding and π…π stacking interactions. Five types of single crystals—obtained by controlling the molecular assembly structures—that exhibit blue, blue-green, and green emission can be obtained, two of which are shown in the figure with their corresponding structures.
Co-reporter:Yi-Shan Yao, Qian-Xiong Zhou, Xue-Song Wang, Yue Wang and Bao-Wen Zhang
Journal of Materials Chemistry A 2006 vol. 16(Issue 34) pp:3512-3520
Publication Date(Web):07 Aug 2006
DOI:10.1039/B604563D
Using 2H-indene-1,3-dione as an electron-withdrawing group and aromatic amines of different structures as electron-donating groups, four new DCM-type dyes, IN-1, IN-2, IN-3, and IN-4, were designed and synthesized for application in organic light-emitting diodes (OLEDs) as red light-emitting materials. IN-2 exhibits a red shift in fluorescence but a blue shift in absorption with respect to IN-1. Similarly, IN-4 exhibits a red shift in fluorescence but a blue shift in absorption with respect to IN-3. These unique photophysical properties were utilized to optimize the electroluminescence color purity and efficiency of these red emitters in OLEDs. In EL devices with the configuration of ITO/NPB (60 nm)/Alq3 (or Gaq3) : red dopant (2.0 wt%) (7 nm)/BCP (12 nm)/Alq3 (45 nm)/LiF (0.3 nm)/Al (300 nm), IN-3 in Alq3 and IN-1 in Gaq3 show CIE coordinates of (0.64, 0.36) and (0.65, 0.34), and current efficiencies of 3.24 cd A−1 and 3.02 cd A−1, respectively, much better than the other guest/host combinations. This can be ascribed to the good spectrum overlap either between IN-3 and Alq3 or between IN-1 and Gaq3, indicating that the absorption spectrum has the same importance as the fluorescence spectrum in the improvement of color purity of red emitters.
Co-reporter:Wei Li, Yaru Nie, Junhu Zhang, Zheng Wang, Difu Zhu, Quan Lin, Bai Yang and Yue Wang
Journal of Materials Chemistry A 2006 vol. 16(Issue 22) pp:2135-2141
Publication Date(Web):04 Apr 2006
DOI:10.1039/B517562C
We report a convenient method for the fabrication of ordered, binary patterned 2D (mdppy)BF arrays on the surface of gold substrates. Ordered arrays of water droplets formed in the hydrophilic regions of patterned self-assembled monolayers (SAMs) which consisted of isolated hydrophobic circles surrounded by a continuous hydrophilic region. Subsequent dewetting of (mdppy)BF solution in chloroform led to the formation of an ordered array of rings in the hydrophilic regions and an ordered array of circles in the hydrophobic regions. The former resulted from a surface-directed and concentration-controlled dewetting process, while the latter was a result of the selective wetting process. Dewetting structures could be controlled by changing the experimental conditions, such as the concentration of the (mdppy)BF solution and the water condensation process.
Co-reporter:Hongyu Zhang, Cheng Huo, Jingying Zhang, Peng Zhang, Wenjing Tian and Yue Wang
Chemical Communications 2006 (Issue 3) pp:281-283
Publication Date(Web):02 Dec 2005
DOI:10.1039/B513918J
A novel multifunctional 1,6-bis(2-hydroxyphenyl)pyridine boron bis(4-n-butyl-phenyl)phenyleneamine compound in which the hole-transporting (HT), electron-transporting (ET), and emitting (EM) components are integrated into a single molecule was synthesized and used as an emitting material to fabricate an efficient single-layer electroluminescent device.
Co-reporter:Yinghui Sun;Kaiqi Ye;Hongyu Zhang;Junhu Zhang;Lan Zhao;Bao Li;Guangdi Yang;Bai Yang Dr.;Siu-Wai Lai Dr.;Chi-Ming Che Dr.
Angewandte Chemie International Edition 2006 Volume 45(Issue 34) pp:
Publication Date(Web):21 AUG 2006
DOI:10.1002/anie.200690115
Co-reporter:Yinghui Sun;Kaiqi Ye;Hongyu Zhang;Junhu Zhang;Lan Zhao;Bao Li;Guangdi Yang;Bai Yang Dr.;Siu-Wai Lai Dr.;Chi-Ming Che Dr.
Angewandte Chemie 2006 Volume 118(Issue 34) pp:
Publication Date(Web):21 AUG 2006
DOI:10.1002/ange.200690115
Co-reporter:Yinghui Sun;Kaiqi Ye;Hongyu Zhang;Junhu Zhang;Lan Zhao;Bao Li;Guangdi Yang;Bai Yang Dr.;Siu-Wai Lai Dr.;Chi-Ming Che Dr.
Angewandte Chemie 2006 Volume 118(Issue 34) pp:
Publication Date(Web):28 JUL 2006
DOI:10.1002/ange.200601588
Auf Draht: PtII⋅⋅⋅PtII-Wechselwirkungen sind die kohäsive Triebkraft für die Bildung von mikro- und nanometerskaligen lumineszierenden Drähten, z. B. von Nanodrähten aus [Pt(CNtBu)2(CN)2] (siehe Bild; Pt pink, N blau, C grau), einem potenziellen Kandidaten für Anwendungen in nanooptischen, elektronischen und Sensorfunktionseinheiten.
Co-reporter:Yinghui Sun;Kaiqi Ye;Hongyu Zhang;Junhu Zhang;Lan Zhao;Bao Li;Guangdi Yang;Bai Yang Dr.;Siu-Wai Lai Dr.;Chi-Ming Che Dr.
Angewandte Chemie International Edition 2006 Volume 45(Issue 34) pp:
Publication Date(Web):28 JUL 2006
DOI:10.1002/anie.200601588
Down to the wire: PtII⋅⋅⋅PtII interactions provide the cohesive driving force for the construction of micro- and nanometer-scale luminescent wires, such as nanowires of [Pt(CNtBu)2(CN)2] (see picture; Pt pink, N blue, C gray), which is a potential candidate for applications in nano-optical, electronic, and sensory devices.
Co-reporter:Huidong Zhang, Yinghui Sun, Kaiqi Ye, Ping Zhang and Yue Wang
Journal of Materials Chemistry A 2005 vol. 15(Issue 31) pp:3181-3186
Publication Date(Web):27 Jun 2005
DOI:10.1039/B503336E
The preparation and properties of luminescent oxygen sensing materials based on two Pt(II)–porphyrin complexes: platinum meso-tetrakis(4-N-methylpyridyl)porphyrin (PtTMPyP4+) and platinum meso-tetrakis(4-N-pyridyl)porphyrin (PtTPyP) assembled in mesoporous silica (MCM-41) are described. The luminescence of Pt(II)–porphyrin/MCM-41 assembly materials can be extremely quenched by molecular oxygen with good sensitivity (I0/I100 > 7) and rapid response times (<1 s) suggest that the Pt(II)–porphyrin/MCM-41 system can be used for developing oxygen sensors. PtTMPyP4+/MCM-41 (20 mg g−1) exhibits very high sensitivity (I0/I100 > 50). Even when the concentration of oxygen is 1%, the luminescence intensity of PtTMPyP4+/MCM-41 (20 mg g−1) can be quenched by 83.33%.
Co-reporter:Shipan Wang, Yuewei Zhang, Weiping Chen, Jinbei Wei, Yu Liu and Yue Wang
Chemical Communications 2015 - vol. 51(Issue 60) pp:NaN11975-11975
Publication Date(Web):2015/06/19
DOI:10.1039/C5CC04469C
Achieving high power efficiencies at high-brightness levels is still an important issue for organic light-emitting diodes (OLEDs) based on the thermally activated delayed fluorescence (TADF) mechanism. Herein, enhanced electroluminescence efficiencies were achieved in fluorescent OLEDs using a TADF molecule, (4s,6s)-2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN), as a host and quinacridone derivatives (QA) as fluorescent dopants.
Co-reporter:Zuolun Zhang, Dandan Yao, Tianlei Zhou, Hongyu Zhang and Yue Wang
Chemical Communications 2011 - vol. 47(Issue 27) pp:NaN7784-7784
Publication Date(Web):2011/06/14
DOI:10.1039/C1CC11882J
Crystalline samples of 3(5)-(9-anthryl)pyrazole and its one derivative exhibit interesting piezochromic behaviors with the emission colors differently changing from blue to green and from green to blue, respectively, upon grinding.
Co-reporter:Tianlei Zhou, Feng Li, Yan Fan, Weifeng Song, Xiaoyue Mu, Hongyu Zhang and Yue Wang
Chemical Communications 2009(Issue 22) pp:NaN3201-3201
Publication Date(Web):2009/05/01
DOI:10.1039/B900476A
A series of aminobenzoic acid crystals with stacking-induced emission properties has been achieved and the packing structures of the hydrogen-bonded acid dimers provided an explanation for the emission characteristics of the crystals.
Co-reporter:Tai Peng, Yu Yang, Yu Liu, Dongge Ma, Zhaomin Hou and Yue Wang
Chemical Communications 2011 - vol. 47(Issue 11) pp:NaN3152-3152
Publication Date(Web):2011/01/27
DOI:10.1039/C0CC04684A
A phosphorescent material (Fppy)2Ir(dipba) possessing high PL efficiency in the solid state and superior hole/electron transporting property has acted successfully as an efficient neat phosphorescent emitter as well as an excellent host for high-performance PHOLEDs.
Co-reporter:Hai Bi, Dong Chen, Di Li, Yang Yuan, Dandan Xia, Zuolun Zhang, Hongyu Zhang and Yue Wang
Chemical Communications 2011 - vol. 47(Issue 14) pp:NaN4137-4137
Publication Date(Web):2011/03/07
DOI:10.1039/C1CC00060H
A novel green emissive Alq3 solid with a facial isomeric form has been obtained by grinding the typical blue luminescent fac-Alq3 crystalline powder. This is the first report, to the best of our knowledge, that a fac-Alq3 isomer emits green light.
Co-reporter:Chenglong Li, Jinbei Wei, Xiaoxian Song, Kaiqi Ye, Hongyu Zhang, Jingying Zhang and Yue Wang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 29) pp:NaN7019-7019
Publication Date(Web):2016/06/27
DOI:10.1039/C6TC01975G
Two phenanthro[9,10-d]imidazole (PI) derivatives, 9-N,N-diphenyl-amino-10-(4-(1-phenyl-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)anthracene (DPAA-PPI) and 9-N,N-dipheny-amino-10-(4-(1-(4-tert-butylphenyl)-1H-phenanthro[9,10-d]imidazol-2-yl)phenyl)anthracene (tBuDPAA-PPI), have been designed and synthesized. The two compounds exhibited high photoluminescence quantum yields (at around 0.80) in the solid state and bipolar carrier transport properties. The non-doped OLEDs using DPAA-PPI and tBuDPAA-PPI as emitting layers showed the maximum power efficiencies (PEs) of 13.9 lm W−1 and 11.4 lm W−1, corresponding to the maximum external quantum efficiencies (EQEs) of 5.2% and 4.1%, respectively. The DPAA-PPI-based OLED exhibited an extremely low turn-on voltage of 2.4 V and its luminescence reached 100, 1000, 10000 and over 100000 cd m−2 under driving voltages of 2.8, 3.6, 5.1 and 7.5 V, respectively.
Co-reporter:Di Li, Hongyu Zhang, Chenguang Wang, Shuo Huang, Jianhua Guo and Yue Wang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 10) pp:NaN4328-4328
Publication Date(Web):2011/12/16
DOI:10.1039/C1JM14606H
2-(2′-Hydroxyphenyl)benzoxazole (HBO) and 2-(2′-hydroxyphenyl)benzothiazole (HBT) reacted with triphenylborane produced two rigid π-conjugated fluorescent cores 1 (BPh2(BOZ), BOZ = 2-(benzo[d]oxazol-2-yl)phenol) and 2 (BPh2(BTZ), BTZ = 2-(benzo[d]thiazol-2-yl)phenol). Comparisons of photophysical properties and calculations between para- and meta-diphenylamine-substituted derivatives 5 (BPh2(para-NPh2-BTZ)) and 7 (BPh2(meta-NPh2-BTZ)) demonstrated that functionalization at the para-position of the rigid core is effective in tuning the electronic structure and hence the photophysical properties of this type of boron-chelate complex. Simple modification of these frameworks by introducing various amine groups at the para-position allows the synthesis of strongly fluorescent materials 3 (BPh2(para-Cz-BTZ), Cz = 9H-carbazol-9-yl), 4 (BPh2(para-NPh2-BOZ), NPh2 = diphenylamino), 5, and 6 (BPh2(para-NMe2-BTZ), NMe2 = dimethylamino). The emission colors of these newly synthesized complexes together with the parent complexes 1 and 2 covered a wide range from deep blue to saturated red in both solution and the solid state. Crystal structure analysis discloses that two phenyl groups attached to the boron atom effectively keep the luminescent ring-fused π-conjugated skeletons apart, making these fluorophores highly emissive in solid forms (ΦF = 0.36–0.71). Organic light-emitting diodes employing these boron complexes as emitters not only keep the full-color tunable emission feature but also show high electroluminescent (EL) performance; for instance, the greenish-blue device based on 2 showed the highest efficiency of 7.8 cd A−1 and the yellow light-emitting device based on 4 exhibited the highest brightness (31220 cd m−2) among the boron-containing emitters reported so far.
Co-reporter:Kai Wang, Shipan Wang, Jinbei Wei, Shanyong Chen, Dong Liu, Yu Liu and Yue Wang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 33) pp:NaN6826-6826
Publication Date(Web):2014/06/30
DOI:10.1039/C4TC00749B
In this work, two novel hybrids of an electron-accepting phosphine oxide moiety attached to a phenanthroimidazole have been designed and synthesized. The PO group is used as a point of saturation between the PPI moiety and the outer phenyl groups, so the high triplet energy of PPI is preserved to act as a host for red and green phosphorescent dopants. The strong intermolecular interactions and steric effect of the diphenylphosphine oxide (DPO) moiety endows the films with high quantum yields in the deep-blue emission region. Compared to PPI, the carrier (hole- and electron-)injection/transport properties were greatly promoted by the appended DPO group according to single-carrier device measurement. Besides, the morphological and thermal stabilities were also improved. The multiple functions enable adaptation of several simplified device configurations. The undoped deep-blue fluorescent device exhibits an external quantum efficiency of 2.24% with CIE (0.16, 0.08), very close to the NTSC blue standard CIE (0.14, 0.08). High performance for green (65.4 cd A−1, 73.3 lm W−1 and 18.0%) and red (19.0 cd A−1, 21.3 lm W−1 and 13.5%) phosphorescent devices used as hosts have been achieved. The experimental and theoretical relationships between the molecular structures and the optoelectronic properties are discussed.
Co-reporter:Tai Peng, Guomeng Li, Kaiqi Ye, Chenguang Wang, Shanshan Zhao, Yu Liu, Zhaomin Hou and Yue Wang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 16) pp:NaN2926-2926
Publication Date(Web):2013/02/27
DOI:10.1039/C3TC00500C
A bipolar iridium complex, (ppy)2Ir(dipig), based on the ancillary ligand N,N′-diisopropyl-diisopropyl-guanidinate (dipig) with well-known cyclometalated (C^N) ligand ortho-(2-pyridyl)phenyl (ppy), is applicable in phosphorescent organic light-emitting diodes (PHOLEDs) as an efficient emitter, using easily available host materials and a simple device fabrication process. The corresponding PHOLEDs are dominated by an efficient direct-exciton-formation mechanism and show very high EL efficiency together with gratifying host- and doping-concentration-independent features. EL efficiency values of more than 93 lm W−1 for power efficiency (ηp) and 24% for external quantum efficiency (ηext) accompanied by little efficiency roll-off at high luminance are achieved in the (ppy)2Ir(dipig)-based devices by adopting the common materials 4,4′-bis(N-(1-naphthyl)-N-phenylamino)biphenyl (NPB) and 1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene (TPBI) as the host, with rather random concentration ranges of 8–15 wt% and 15–30 wt%, respectively. To the best of our knowledge, these values are the highest efficiencies ever reported for yellow PHOLEDs, and are even comparable with the highest levels for PHOLEDs in the scientific literature. Moreover, the ηp and ηext values of the non-doped device can reach 70 lm W−1 and 18% respectively. They are almost two times higher than those of the most efficient reported PHOLEDs based on a neat emitting layer (EML).
Co-reporter:Chenguang Wang, Dong Chen, Weiping Chen, Shanyong Chen, Kaiqi Ye, Hongyu Zhang, Jingying Zhang and Yue Wang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 35) pp:NaN5556-5556
Publication Date(Web):2013/07/08
DOI:10.1039/C3TC30803K
The structures and properties of an indole-ring-fused quinacridone derivative 5,8,15,18-tetraoctyl-5,8,15,18-tetrahydroindolo[3,2-a]indole[3′,2′:5,6]quinacridone (IDQA), which was synthesized by an improved procedure, have been carefully investigated and compared with its parent compound N,N′-di(n-octyl)quinacridone (C8-QA). Concentration-dependent 1H NMR spectra revealed that the strong aggregations of IDQA existed in solution because of the flat and extended π-conjugation. Two polymorphs of IDQA with and without π⋯π interactions exhibited red and non emissions, respectively. One-dimensional micromaterials with different morphologies constructed by IDQA molecules were fabricated by a reprecipitation approach and they displayed different emission properties due to the different molecular packing. The nine-ring fused flat skeleton endowed this material with several elegant properties, including a high photoluminescent quantum yield in solution, and a high thermal and electrochemical stability. Therefore, the efficient doped organic light emitting device (OLED) with IDQA as the emitter was fabricated. Moreover, the large π-conjugation system endowed the IDQA thin film with ordered molecular packing and good hole transport properties (hole mobility μh = 0.047 cm2 V−1 s−1).
Co-reporter:Xiao Cheng, Shuheng Sun, Youchun Chen, Yajun Gao, Lin Ai, Tao Jia, Fenghong Li and Yue Wang
Journal of Materials Chemistry A 2014 - vol. 2(Issue 31) pp:NaN12491-12491
Publication Date(Web):2014/05/23
DOI:10.1039/C4TA01586J
A novel organic small molecule water-soluble poly-N-alkylpyridine substitued metallophthalocyanine derivative VOPc(OPyCH3I)8, namely 2,3,9,10,16,17,23,24-octakis-[N-methyl-(3-pyridyloxy)] vanadylphthalocyanine iodide (1:8), was synthesized and applied in polymer solar cells (PSCs). Notably, a power conversion efficiency (PCE) of 8.12% for the working area of 2 × 2 mm2 and a PCE of 7.23% for the working area of 4 × 4 mm2 have been achieved in the PSCs with this molecule as a cathode interlayer. They are comparable with the higher values of PCE of the PSCs reported currently, indicating that VOPc(OPyCH3I)8 is a new promising candidate as a good cathode interlayer for highly efficient PSCs.
Co-reporter:Shanshan Zhao, Fei Yu, Guochun Yang, Hongyu Zhang, Zhongmin Su and Yue Wang
Dalton Transactions 2012 - vol. 41(Issue 24) pp:NaN7277-7277
Publication Date(Web):2012/04/20
DOI:10.1039/C2DT00009A
To deeply understand the charge-transporting nature of Pt(CNtBu)2(CN)2 nanowires induced by intermolecular Pt⋯Pt interactions, calculations based on first-principle band structure and Marcus theory have been performed. The calculated bandwidths of the valence band, conducting band, and the effective masses of hole and electron are almost equal. This suggests that this complex has ambipolar transport characteristics, in agreement with experimental results. Density of states analysis revealed that the hole transport resulted mainly from the Pt⋯Pt interactions, while the electron transport was derived mainly from the CN groups. The character of the frontier molecular orbitals, reorganization energies and transfer integrals in different directions also supports the calculated first-principle band structure. Moreover, an investigation into the intermolecular interaction energy of neighbors revealed that there is a remarkable relationship between the intermolecular interaction energy and the transfer integral.
Co-reporter:Yu Zhang, Hongyu Zhang, Xiaoyue Mu, Siu-Wai Lai, Bin Xu, Wenjing Tian, Yue Wang and Chi-Ming Che
Chemical Communications 2010 - vol. 46(Issue 41) pp:NaN7729-7729
Publication Date(Web):2010/09/20
DOI:10.1039/C0CC02242J
The ordered [Pt(CN-tBu)2(CN)2] semiconducting microwires have been prepared on substrates based on solvent evaporation or dip–and–pull approaches and were found to display photo- and vapor-responsive conducting characteristics.
Co-reporter:Chenguang Wang, Kai Wang, Qiang Fu, Jingying Zhang, Dongge Ma and Yue Wang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 3) pp:NaN413-413
Publication Date(Web):2012/11/20
DOI:10.1039/C2TC00419D
Pentaphenylphenyl substituted quinacridone (QA) derivative BPP–QA with two propeller-like substituted groups was synthesized and showed intense emission in both solution and solid state.
Co-reporter:Tao Jia, Weilong Zhou, Youchun Chen, Jianxiong Han, Lu Wang, Fenghong Li and Yue Wang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 8) pp:NaN4554-4554
Publication Date(Web):2015/01/08
DOI:10.1039/C4TA06601D
A new cathode interlayer (CIL) material metallophthalocyanine (MPc) derivative 1,4,8,11,15,18,22,25-octaoctyloxy-2,3,9,10,16,17,23,24-octa-[N-methyl-(3-pyridyloxy)] zinc-ylphthalocyanine iodide (1:8) (ZnPc(OC8H17OPyCH3I)8) was synthesized and applied in polymer solar cells (PSCs) based on PTB7:PC71BM (PTB7 = thieno[3,4-b]thiophene/benzodithiophene, PC71BM = [6,6]-phenyl C71-butyric acidmethyl ester), P3HT:PC61BM (P3HT = poly(3-hexylthiophene), PC61BM = [6,6]-phenyl C61-butyric acidmethyl ester) or PCDTBT:PC71BM (PCDTBT = poly[N-9′′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]) as an active layer. As a result, power conversion efficiency (PCE) values of the PSCs were 8.52%, 4.02% and 6.88%, respectively, which are much higher than those of corresponding PSCs with the Al-only cathode. It indicates that ZnPc(OC8H17OPyCH3I)8 is a new promising candidate as a universal CIL for highly efficient PSCs. Compared to VOPc(OPyCH3I)8 (2,3,9,10,16,17,23,24-octakis-[N-methyl-(3-pyridyloxy)] vanadylphthalocyanine iodide (1:8)), the PSC with ZnPc(OC8H17OPyCH3I)8 as a CIL has higher short-circuit current and fill factor because ZnPc(OC8H17OPyCH3I)8 can form a better, denser, and more uniform film on the active layer than VOPc(OPyCH3I)8 as demonstrated by atomic force microscopy (AFM), energy-dispersive spectrum mapping on scan electron microscopy (SEM-EDS mapping) and contact angle measurements.
Co-reporter:Weiping Chen, Junjie Lv, Jianxiong Han, Youchun Chen, Tao Jia, Fenghong Li and Yue Wang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 6) pp:NaN2177-2177
Publication Date(Web):2016/01/18
DOI:10.1039/C5TA09701K
A new π-conjugated electrolyte bis(dicyanomethylene)-quinacridone with two octyl-pyridium (DCNQA-PyBr) has been synthesized and employed as a solution-processed cathode interlayer (CIL) for polymer solar cells (PSCs). The devices exhibited simultaneously increased open-circuit voltage (Voc), short-circuit current (Jsc) and fill factor (FF). Overall, the PSCs with PCDTBT (poly[N-9′′-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)]) as a donor and PC71BM ([6,6]-phenyl C71-butyric acid methyl ester) as an acceptor incorporating a 13 nm DCNQA-PyBr interlayer exhibit a power conversion efficiency (PCE) of 6.96%, which is 1.3 times of that of the Al-only device. Most importantly, compared to the reference π-conjugated electrolyte QA-PyBr, DCNQA-PyBr shows much improved electron transport ability and conductivity. As a result, the DCNQA-PyBr based devices only show a slight decrease in electron transport upon increasing the thickness of the CIL, thus allowing a high PCE with a wide CIL thickness range from 5 nm to 40 nm. Furthermore, introducing DCNQA-PyBr as a CIL into the devices based on P3HT:PC61BM (P3HT = poly(3-hexylthiophene), PC61BM = [6,6]-phenyl C61-butyric acid methyl ester) and PTB7:PC71BM (PTB7 = polythieno[3,4-b]-thiophene-co-benzodithiophene) also leads to significantly enhanced device performance, showing high PCEs of 3.91% and 8.23%, respectively. These results confirm DCNQA-PyBr to be a promising CIL material for solution-processed large-area PSCs.
Co-reporter:Liang Han, Yuewei Zhang, Weiping Chen, Xiao Cheng, Kaiqing Ye, Jingying Zhang and Yue Wang
Chemical Communications 2015 - vol. 51(Issue 21) pp:NaN4480-4480
Publication Date(Web):2015/02/16
DOI:10.1039/C5CC00476D
Acenaphtho[1,2-k]fluoranthene derivatives DPAF-n as new building blocks for one-dimensional (1D) structure assembly have been developed and employed to fabricate luminescent twisted nano/micro-wires; and the DPAF rigid core attached via flexible alkyl chains with suitable lengths is critical for the formation of twisted architectures.
Co-reporter:Dandan Yao, Shanshan Zhao, Jianhua Guo, Zuolun Zhang, Hongyu Zhang, Yu Liu and Yue Wang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 11) pp:NaN3570-3570
Publication Date(Web):2011/02/09
DOI:10.1039/C1JM00009H
Two sets of hydroxyphenyl-benzothiazole based compounds, which exhibited emission colors across the entire visible spectrum for both photoluminescence and electroluminescence, have been designed and synthesized.
Co-reporter:Tai Peng, Yu Yang, Hai Bi, Yu Liu, Zhaomin Hou and Yue Wang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 11) pp:NaN3553-3553
Publication Date(Web):2011/01/19
DOI:10.1039/C0JM03645E
A high-efficiency and pure white OLED has been realized by only doping one novel phosphorescent orange-light-emitting complex (bzq)2Ir(dipba) into a suitable deep-blue-emitting fluorescent complex Bepp2 as an emissive layer. The highest efficiency for white OLEDs with a simple HTL-EML-ETL architecture, with a peak power efficiency (PE) of 48.8 lm W−1 and a peak external quantum efficiency (EQE) of 27.8%, has been realized by employing both singlet and triplet excitons for emission. The PE and EQE at the applicable brightness of 1000 cd m−2 are 37.5 lm W−1 and 36.8%, respectively.
Co-reporter:Shanyong Chen, Jinbei Wei, Kai Wang, Chenguang Wang, Dong Chen, Yu Liu and Yue Wang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 40) pp:NaN6602-6602
Publication Date(Web):2013/08/09
DOI:10.1039/C3TC31271B
Two new indolo[3,2-b]carbazole derivatives (DPDT-ICZ and DNDT-ICZ) with multifunctionality were designed and synthesized. They were employed as deep-blue emitters, hole-transporting materials and hosts to fabricate organic light-emitting devices (OLEDs). The devices which used them as emitters displayed deep-blue emissions with CIE coordinates of (0.15, 0.08). They have been employed as hole-transporting and host material simultaneously to construct high performance yellow and red phosphorescent OLEDs. High power efficiencies (78.3 lm W−1 for yellow devices and 20.4 lm W−1 for red devices) for phosphorescent OLEDs were achieved. Importantly, these devices displayed the feature of low roll-off of efficiencies. At the luminance of 1000 cd m−2, roll-off of current efficiencies was 1.3% for the yellow device and 14.6% for the red device.
Co-reporter:Di Li, Hongyu Zhang and Yue Wang
Chemical Society Reviews 2013 - vol. 42(Issue 21) pp:NaN8433-8433
Publication Date(Web):2013/07/30
DOI:10.1039/C3CS60170F
Four-coordinate organoboron compounds with rigid π-conjugated structures are intensely luminescent and have high carrier mobility which enables them to be applied in optoelectronics including organic light-emitting diodes (OLEDs), organic field-effect transistors, as well as photoresponsive, sensory and imaging materials. Various chelate ligands and boron moieties have been explored to construct proper electronic structures and suitable molecular arrangements, which play important roles on the photophysical and electronic properties of the four coordinate boron compounds. These efforts have produced a number of fascinating molecules, some of which have exhibited high performance as light emitting materials. In this article, we provide an overview of the progress in the molecular construction of four-coordinate organoboron compounds with an emphasis on their applications in OLEDs.
Co-reporter:Chenglong Li, Shipan Wang, Weiping Chen, Jinbei Wei, Guochun Yang, Kaiqi Ye, Yu Liu and Yue Wang
Chemical Communications 2015 - vol. 51(Issue 53) pp:NaN10635-10635
Publication Date(Web):2015/05/21
DOI:10.1039/C5CC03492B
Two deep blue emitting materials PPI-PPITPA and PPI-PPIPCz with dual carrier transport properties and small singlet–triplet splitting features are designed and synthesized. PPI-PPITPA and PPI-PPIPCz were used not only as non-doped emitting layers to fabricate highly efficient deep blue OLEDs, but also as hosts to construct high performance green, yellow and red phosphorescent OLEDs.
Co-reporter:Chenglong Li, Zhiqiang Li, Xianju Yan, Yuewei Zhang, Zuolun Zhang and Yue Wang
Journal of Materials Chemistry A 2017 - vol. 5(Issue 8) pp:NaN1980-1980
Publication Date(Web):2017/01/23
DOI:10.1039/C6TC05639C
Blue organic light-emitting diodes (OLEDs) are crucial for flat-panel displays and solid-state lighting. Regarding the practical application of OLEDs, high luminance and efficiencies at a low driving voltage, as well as a simple device structure, are highly desirable. However, blue OLEDs fulfilling these requirements are rare. Herein, two new sky-blue emitters, TPA-An-PPI and PCz-An-PPI, with the integration of wide-bandgap phenanthro[9,10-d]imidazole, anthracene and aromatic amine groups have been synthesized. They possess good thermal stability, bright emission in the solid state, as well as the bipolar carrier-transporting ability. Structurally simple non-doped sky-blue OLEDs with TPA-An-PPI as the emitting layer showed high performance, with the maximum luminance (Lmax) of 51390 cd m−2, the maximum power efficiency (PEmax) of 10.42 lm W−1, and the maximum external quantum efficiency (EQEmax) of 4.61%. More importantly, at a practical high luminance of 1000 cd m−2, the PE and EQE retained high values of 8.48 lm W−1 and 4.60%, respectively, and the corresponding driving voltage was as low as 3.6 V. The performance of the non-doped device based on PCz-An-PPI was also high, although being lower than that of TPA-An-PPI.
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