Ping Lu

Find an error

Name: 路萍; Lu, Ping

Organization: Jilin University , China

Department: State Key Laboratory of Supramolecular Structure and Materials

Title: Associate Professor(PhD)

TOPICS

Polymer

Material Chemistry

OLED

Organic Chemistry

OLED

Chemicals
References

E/Z isomerization, solvatachromism and aggregation-induced emission enhancement of donor–acceptor type oligo(p-phenylene vinylene)s

Co-reporter:Cunfang Feng;Jinyu Li;Xiao Han;Xin He;Liqun Liu;Xiaoxiao Li;Xiaoyi Sun;Yuguang Ma

Faraday Discussions 2017 (Volume 196) pp:163-176

Publication Date(Web):2017/02/20

DOI:10.1039/C6FD00159A

A donor–acceptor molecule, PICNDSB, with cyclopenta[b]indole as the donor and (1,4-phenylene)bis(3-phenylacrylonitrile) as the acceptor, is designed and synthesized. PICNDSB shows typical aggregation-induced emission characteristics. The photoluminescence quantum yield of PICNDSB in dilute THF was only 0.7% and reaches 51.4% in the solid state. Compared with its analogue CzCNDSB, PICNDSB possesses stronger intramolecular charge transfer properties, as revealed from CV measurements, theoretical calculations, and their fluorescence behaviors. Correspondingly, the relatively more efficient electron-donating terminal group of cyclopenta[b]indole endows the molecule with a much higher two-photon absorption cross section of 1286 GM compared to CzCNDSB (357 GM).

The effect of different binding sites on the optical and electronic properties of tetraphenylethylene-substituted thiophene isomers

Co-reporter:Jinyu Li;Tong Shan;Mingming Yao;Yu Gao;Xiao Han;Bing Yang

Journal of Materials Chemistry C 2017 vol. 5(Issue 10) pp:2552-2558

Publication Date(Web):2017/03/09

DOI:10.1039/C6TC05653A

Thiophene has attracted tremendous attention in the field of optoelectronics. Here, a series of isomers containing TPE and thiophene are designed and synthesized by Suzuki coupling reactions. TPE groups were attached to the thiophene core at the 2,5-positions (M1), 3,4-positions (M2), 2,3-positions (M3) and 2,4-positions (M4), to endow the resultant molecules with not only various geometries but also high solid-state efficiencies. All the isomers are thermally stable and show good solubility in common organic solvents. They all emit weakly in solution but become strong emitters when fabricated into solid films. Isomer M1 has a more planar space arrangement and exhibits a relatively narrower optical bandgap with respect to the other three isomers. Non-doped OLEDs using the four isomers as light-emitting layers are constructed. M1 gives excellent device performance with a maximum luminance of 65 210 cd m−2, a maximum current efficiency of 11.21 cd A−1 and a maximum EQE of 4.49%.

Dual fluorescence polymorphs: Wide-range emission from blue to red regulated by TICT and their dynamic electron state behavior under external pressure

Co-reporter:Zhe Zhang, Yu Gao, He Liu, Qing Bai, Jinyu Li, Liqun Liu, Changfeng Wu, Bing Yang, Kai Wang, Bo Zou, Yan Wang, Ping Lu

Dyes and Pigments 2017 Volume 145(Volume 145) pp:

Publication Date(Web):1 October 2017

DOI:10.1016/j.dyepig.2017.06.025

•Dual fluorescence induced by polymorph is investigated in crystals.•The single-crystal study reveals that dual fluorescence is caused by different twist angle, which gives a direct observation that supported the twisted intramolecular charge transfer states (TICT) model.•The external pressure was applied to adjust the fluorescence behavior from a dual emission to a LE emission by changing the twist angel.Organic fluorescence molecules have attracted great interest in the last decades, due to their adjustable fluorescence properties and broad applications in organic electroluminescence display, fluorescence labelling, biological imaging, and so on. Conformation is one of the most important factors that determines organic molecular fluorescence properties. Herein, a compound, DBTO-PTZ, with five polymorphs was demonstrated. Distinctive polymorph-dependent optical characteristics were observed in these polymorphs, which gives an ideal model for the investigation of relationship between conformation and fluorescence property. Three of them display distinct dual fluorescence which is not observed in solution or the other two crystals. It is found that the twist angle between DBTO and PTZ units is a critical factor to determine the polymorphs of DBTO-PTZ and corresponding fluorescence behaviors. This result provides a direct proof to support the TICT model. Moreover, the external pressure was applied to adjust the fluorescence behavior from a dual emission to a single LE emission, which further proves the mechanism of TICT. This work will contribute to the understanding between conformation and optical characteristics. It also sheds light on a new strategy to fine-tune the fluorescence property.Download high-res image (304KB)Download full-size image

Highly efficient and stable pure blue nondoped organic light-emitting diodes at high luminance based on phenanthroimidazole-pyrene derivative enabled by triplei-triplet annihilation

Co-reporter:Tong Shan, Zhao Gao, Xiangyang Tang, Xin He, Yu Gao, Jinyu Li, Xiaoyi Sun, Yulong Liu, Haichao Liu, Bing Yang, Ping Lu, Yuguang Ma

Dyes and Pigments 2017 Volume 142(Volume 142) pp:

Publication Date(Web):1 July 2017

DOI:10.1016/j.dyepig.2017.03.032

•Three naphthalene, pyrene and anthracene-substituted phenanthroimidazole derivatives are developed, respectively.•Pyrene and anthracene-containing derivatives exhibit TTA characteristics.•The nondoped OLED of 2 demonstrates a stable pure blue emission (CIE (0.15, 0.14)) and a maximum luminance of 54300 cd m-2.•The EQE reaches 5.11% and maintains EQE over 5% at luminance of 300∼3000 cd m-2.To promote the application of organic light emitting diodes (OLEDs) in various areas, achieving high performance blue OLEDs with outstanding efficiencies at high luminance is still desired. Herein, we focus on realizing stable and highly efficient pure blue OLED capable of harvesting triplets via triplet-triplet annihilation (TTA). Three fused polycyclic aromatic substituents, naphthalene, pyrene and anthracene, are selected to construct phenanthroimidazole-functionalized molecules (1–3), among which pyrene and anthracene comprised ones display TTA characteristics in electroluminescence devices. High photoluminescence quantum efficiency of 57% is found in the neat film of emitter 2 from judicious molecular design. The nondoped OLED of 2 exhibits pure blue emission with CIE coordinates of (0.15, 0.14) and demonstrates a maximum external quantum efficiency (EQE) of 5.11%, stable EQE over 5% at luminance of 300–3000 cd m-2, EQE of 4.76% at an ultra-bright luminance of 10000 cd m-2 and a maximum luminance of 54300 cd m-2. Such great device performance are responsible for the appreciable TTA contribution substantially.Download high-res image (272KB)Download full-size image

Synthesis and properties of polymeric host materials constructed by silane-carbazole backbone and electron-affinitive cyanohexyl substituent for blue phosphorescence dopant

Co-reporter:Dehua Hu;He Liu;Xiaoxiao Li;Xiaoyi Sun

Chemical Research in Chinese Universities 2017 Volume 33( Issue 2) pp:287-293

Publication Date(Web):15 March 2017

DOI:10.1007/s40242-017-6477-3

A series of blue phosphor hosts, using 3,6-linked carbazole with δ-π tetraphenylsilane segment as the main chain and modified by peripheral cyanohexyl group with different ratios, was designed and synthesized. These polymers show good solubility in common organic solvents. They all possess wide bandgap of 3.40 eV, high thermal stabilities and good film forming abilities. The peripheral cyanohexyl substituents have no effect on the polymer backbones but enhance the electron transporting properties of the polymers in devices. Among them, doped devices using poly[(tetraphenylsilicon/9-hexyl-9H-3,6-carbazole)50-co-(tetraphenylsilicon/9-hexanenitrile-9H-3,6-carbazole)50 (PCNCzSi50) as the host and bis[(4,6-difluorophenyl)pyridinato-N,C2]-(picolinato)iridium(III)(FIrpic) as the guest show the best performance with the maximum current efficiency and power efficiency of 2.00 cd/A and 1.40 lm/W, respectively.

Bright AIE Nanoparticles with F127 Encapsulation for Deep-Tissue Three-Photon Intravital Brain Angiography

Co-reporter:Yalun Wang;Xiao Han;Wang Xi;Jinyu Li;Anna Wang Roe;Jun Qian

Advanced Healthcare Materials 2017 Volume 6(Issue 21) pp:

Publication Date(Web):2017/11/01

DOI:10.1002/adhm.201700685

AbstractDeep-tissue imaging is of great significance to biological applications. In this paper, a deep-red emissive luminogen 2,3-bis(4′-(diphenylamino)-[1,1′-biphenyl]-4-yl) fumaronitrile (TPATCN) with aggregation-induced emission (AIE) feature is prepared. TPATCN molecules were then encapsulated within a polymeric matrix of Pluronic F-127 to form nanoparticles (NPs). TPATCN NPs exhibit bright three-photon fluorescence (3PF) in deep-red region, together with high chemical stability, good photostability, and biocompatibility. They are further utilized for in vivo 3PF imaging of the brain vasculature of mice, under the excitation of a 1550 nm femtosecond laser. A vivid 3D reconstruction of the brain vasculature is then built with a penetration depth of 875 µm, which is the largest in ever reported 3PF imaging based on AIE NPs. After that, by collecting both of the 3PF and third-harmonic generation signals, multichannel nonlinear optical imaging of the brain blood vessels is further realized. These results will be helpful to study the structures and functions of the brain in the future.

Efficient Deep-Blue Electroluminescence Based on Phenanthroimidazole-Dibenzothiophene Derivatives with Different Oxidation States of the Sulfur Atom

Co-reporter:Xiangyang Tang;Tong Shan;Qing Bai;Hongwei Ma;Xin He; Ping Lu

Chemistry – An Asian Journal 2017 Volume 12(Issue 5) pp:552-560

Publication Date(Web):2017/03/02

DOI:10.1002/asia.201601626

AbstractDeveloping efficient deep-blue materials is a long-term research focus in the field of organic light-emitting diodes (OLEDs). In this paper, we report two deep-blue molecules, PITO and PISF, which share similar chemical structures but exhibit different photophysical and device properties. These two molecules consist of phenanthroimidazole and dibenzothiophene analogs. The distinction of their chemical structures lies in the different oxidation states of the S atom. For PITO, the S atom is oxidized and the resulting structure dibenzothiophene S,S-dioxide becomes electron deficient. Therefore, PITO displays remarkable solvatochromism, implying a charge-transfer (CT) excited state formed between the donor (D) phenanthroimidazole and acceptor (A) dibenzothiophene S,S-dioxide. For PISF, it is constituted of phenanthroimidazole and dibenzothiophene in which the S atom is not oxidized. PISF displays locally excited (LE) emission with little solvatochromism. Compared with PISF, the D–A molecule PITO with an electron-deficient group shows a much lower LUMO energy level, which is in favor of electron injection in device. In addition, PITO exhibits more balanced carrier transport. However, PISF is capable of emitting in the shorter wavelength region, which is beneficial to obtain better color purity. The doped electroluminescence (EL) device of the D–A molecule PITO manifests deep-blue emission with CIE coordinates of (0.15, 0.08) and maximum external quantum efficiency (EQE) of 4.67 %. The doped EL device of the LE molecule PISF, however, reveals an even bluer emission with CIE coordinates of (0.15, 0.06) and a maximum EQE of 4.08 %.

Electropolymerized AIE-active polymer film with high quantum efficiency and its application in OLED

Co-reporter:

Journal of Polymer Science Part A: Polymer Chemistry 2017 Volume 55(Issue 4) pp:707-715

Publication Date(Web):2017/02/15

DOI:10.1002/pola.28414

ABSTRACTA carbazole functionalized electro-active AIE-activity molecule, TPE-DFCz, was designed, synthesized, and well characterized. The clear difference in oxidation potentials between tetraphenylethylene (TPE) unit and carbazole groups was found which guaranteed that polymerization occurred only at the peripheral carbazole groups and the TPE unit remained unchanged. Its luminescent network film was prepared conveniently by electrochemical polymerization (EP). The cross-linked film exhibited green emission with high quantum efficiency of 63%, relatively smooth surface, and good thermal stability. The effect of different scan cycles on the optical property was also investigated. The electroluminescent device using the optimized polymer film as active layer showed a maximum luminance of 3200 cd m−2 and a maximum luminance efficiency of 1.16 cd A−1 with very low roll-off of the efficiency. The AIE-active EP films afford more opportunities to develop polymer films with high quantum efficiency via a simple, effective method and promote the potential applications in display devices. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017, 55, 707–715

Enhanced Sensitivity and Piezochromic Contrast through Single-Direction Extension of Molecular Structure

Co-reporter:Dr. Zhao Gao;Dr. Kai Wang;Dr. Fangming Liu;Dr. Cunfang Feng;Dr. Xin He;Dr. Jinyu Li; Bing Yang; Bo Zou; Ping Lu

Chemistry - A European Journal 2017 Volume 23(Issue 4) pp:773-777

Publication Date(Web):2017/01/18

DOI:10.1002/chem.201604923

AbstractTwo piezochromic materials containing phenanthro[9,10-d]imidazole and tetraphenylethylene (M1 and M2) were developed. A supra-amplification piezochromic effect originating from their various long-to-short axis ratios was discovered in high-pressure experiments. Based on the linear relationship between applied pressure and emission-peak wavelength during pressurizing and depressurizing cycles, quantitative sensitivity for piezochromism could be denoted. M2 displayed higher piezochromic contrast (102 nm) and better sensitivity (11.19 nm GPa−1) than M1 (69 nm and 6.12 nm GPa−1), which helps to develop a more comprehensive general strategy to evaluate pressure-responsive performance.

D-A structured high efficiency solid luminogens with tunable emissions: Molecular design and photophysical properties

Co-reporter:Yunzhong Wang, Zihan He, Gan Chen, Tong Shan, ... Yongming Zhang

Chinese Chemical Letters 2017 Volume 28, Issue 11(Volume 28, Issue 11) pp:

Publication Date(Web):1 November 2017

DOI:10.1016/j.cclet.2017.09.054

Fabrication of efficient solid luminogens with tunable emission is both fundamentally significant and technically important. Herein, based on our previous strategy for the construction of efficient and multifunctional solid luminogens through the combination of diverse aggregation-induced emission (AIE) units with other functional moieties, a group of luminophores with electron donor-acceptor (D-A) structure and typical intramolecular charge transfer (ICT) characteristics, namely CZ-DCDPP, DPA-DCDPP and DBPA-DCDPP were synthesized and investigated. The presence of twisting and AIE-active 2,3-dicyano-5,6-diphenylpyrazine (DCDPP) moiety endows them highly emissive in the solid states, whereas the introduction of arylamines with varied electron-donating capacity and different conjugation render them with tunable solid emissions from green to red. While CZ-DCDPP and DPA-DCDPP solids exhibit distinct mechanochromism, both DPA-DCDPP and DBPA-DCDPP solids can generate efficient red emission. Owing to their high efficiency, remarkable thermal and morphological stabilities and moreover red emission, they are promising for diverse optoelectronic and biological applications.Download high-res image (168KB)Download full-size image

Unique piezochromic fluorescence behavior of organic crystal of carbazole-substituted CNDSB

Co-reporter:Cunfang Feng, Kai Wang, Yuanxiang Xu, Liqun Liu, Bo Zou and Ping Lu

Chemical Communications 2016 vol. 52(Issue 19) pp:3836-3839

Publication Date(Web):03 Feb 2016

DOI:10.1039/C5CC09152G

CzCNDSB with a highly twisted conformation in the solid state is constructed. Single crystal measurements prove that it possesses an inside pore with a diameter of 8 Å and further forms a long-range orderly arrayed channel. CzCNDSB can sense external pressure from 1.0 atm to 9.21 GPa, accompanied by color changes from green to red with excellent reversibility and reproducibility.

Highly Efficient Deep Blue Organic Light-Emitting Diodes Based on Imidazole: Significantly Enhanced Performance by Effective Energy Transfer with Negligible Efficiency Roll-off

Co-reporter:Tong Shan, Yulong Liu, Xiangyang Tang, Qing Bai, Yu Gao, Zhao Gao, Jinyu Li, Jian Deng, Bing Yang, Ping Lu, and Yuguang Ma

ACS Applied Materials & Interfaces 2016 Volume 8(Issue 42) pp:28771

Publication Date(Web):October 10, 2016

DOI:10.1021/acsami.6b10004

Great efforts have been devoted to develop efficient deep blue organic light-emitting diodes (OLEDs) materials meeting the standards of European Broadcasting Union (EBU) standard with Commission International de L’Eclairage (CIE) coordinates of (0.15, 0.06) for flat-panel displays and solid-state lightings. However, high-performance deep blue OLEDs are still rare for applications. Herein, two efficient deep blue emitters, PIMNA and PyINA, are designed and synthesized by coupling naphthalene with phenanthreneimidazole and pyreneimidazole, respectively. The balanced ambipolar transporting natures of them are demonstrated by single-carrier devices. Their nondoped OLEDs show deep blue emissions with extremely small CIEy of 0.034 for PIMNA and 0.084 for PyINA, with negligible efficiency roll-off. To take advantage of high photoluminescence quantum efficiency of PIMNA and large fraction of singlet exciton formation of PyINA, doped devices are fabricated by dispersing PyINA into PIMNA. A significantly improved maximum external quantum efficiency (EQE) of 5.05% is obtained through very effective energy transfer with CIE coordinates of (0.156, 0.060), and the EQE remains 4.67% at 1000 cd m–2, which is among the best of deep blue OLEDs reported matching stringent EBU standard well.Keywords: ambipolar; deep blue; efficiency roll-off; energy transfer; OLEDs

Adjusting Nitrogen Atom Orientations of Pyridine Ring in Tetraphenylsilane-Based Hosts for Highly Efficient Blue Phosphorescent Organic Light-Emitting Devices

Co-reporter:Qing Bai, He Liu, Liang Yao, Tong Shan, Jinyu Li, Yu Gao, Zhe Zhang, Yulong Liu, Ping Lu, Bing Yang, and Yuguang Ma

ACS Applied Materials & Interfaces 2016 Volume 8(Issue 37) pp:24793

Publication Date(Web):August 31, 2016

DOI:10.1021/acsami.6b09488

Four wide bandgap host materials, namely, 9-(4-diphenyl(4-(pyridin-3-yl)phenyl)silyl-phenyl)-9H-carbazole (CSmP), 9-(4-diphenyl(4-(pyridin-2-yl)phenyl)silylphenyl)-9H-carbazole (CSoP), 9-(4-diphenyl(4-(pyridin-3-yl)phenyl)silylphenyl)-9H-3,9′-bicarbazole (DCSmP), and 9-(4-(diphenyl(4-(pyridin-2-yl)phenyl)silyl)phenyl)-9H-3,9′-bicarbazole (DCSoP), have developed by incorporation of pyridine with varied N atom orientation and carbazole/dimer carbazole units into the tetraphenylsilane skeleton for blue phosphorescent light-emitting diodes. These host materials all possess wide bandgap (3.54–3.64 eV) and high triplet energies (2.77–2.95 eV). As revealed by the absorption and emission spectra, theoretical calculations, and CV measurements, the N atom orientation exerts a strong influence on the LUMO energy level and electron-transportation behaviors without deterioring the photophysical properties. Among them, DCSmP with 3-pyridyl substituent manifests the best electron-transporting capability. The FIrpic-doped blue phosphorescent device using DCSmP as host material exhibits excellent electroluminescence performance with a maximum current efficiency of 40.1 cd A–1 and a maximum external quantum efficiency of 20.0%. The current efficiency and external quantum efficiency are improved 3-fold, higher than those fabricated from DCSpP with 4-pyridyl as substituent, demonstrating an effective strategy for large improvement in device performance by a subtle change in molecular structure.Keywords: blue PhOLED; carbazole; pyridine; tetraarylsilane; wide bandgap

Efficient pyrene-imidazole derivatives for organic light-emitting diodes

Co-reporter:Yulong Liu, Qing Bai, Jinyu Li, Shitong Zhang, Chen Zhang, Fang Lu, Bing Yang and Ping Lu

RSC Advances 2016 vol. 6(Issue 21) pp:17239-17245

Publication Date(Web):02 Feb 2016

DOI:10.1039/C5RA25424H

Two light emitting materials, 9-phenyl-10-(4-(1,2,2-triphenylvinyl)phenyl)-9H-pyreno[4,5-d]imidazole (PyTPEI) and 9-phenyl-10-(4′-(1,2,2-triphenylvinyl)-[1,1′-biphenyl]-4-yl)-9H-pyreno[4,5-d]imidazolepyreneimidazole (PyPTPEI), containing pyrene, imidazole and tetraphenylethene units are synthesized with high yields. Both of them exhibit good thermal stability with decomposition temperatures of 458 °C and 474 °C, respectively. The fluorescent quantum efficiency in amorphous films are as high as 70% for PyTPEI and 63% for PyPTPEI, respectively. In particular, PyPTPEI shows blue-shifted emission due to the more twisted conformation and reduced intermolecular interactions as compared with PyTPEI. The maximum current efficiency and maximum brightness of a non-doped OLED device using PyTPEI as an active layer reaches 8.73 cd A−1 and 27419 cd m−2, which is better than that of PyPTPEI (7.68 cd A−1 and 19419 cd m−2).

A highly luminescent organic crystal with the well-balanced charge transport property: The role of cyano-substitution in the terminal phenyl unit of distyrylbenzene

Co-reporter:Huan Wang, Fenglong Sun, Yang Zhao, Ping Lu, Baohui Wang, Huaiyuan Wang

Organic Electronics 2016 Volume 28() pp:287-293

Publication Date(Web):January 2016

DOI:10.1016/j.orgel.2015.11.008

•Cyano-substituted on terminal phenyl units of distyrylbenzene crystal was prepared.•The crystal (2-CSB) presents a high luminescence efficiency of ∼55%.•The crystal hole and electron mobilities are 0.66 and 0.29 cm2/Vs, respectively.•Intermolecular C–H…N interactions induce a face-to-face slipped π stacking motif.1,4-bis(2-cyano styryl)benzene (2-CSB) crystal with cyano substituent groups introduced to the terminal phenyl rings of distyrylbenzene (DSB) has been prepared and its luminescence efficiency could be as high as ∼55%. Based on the analyses of cyclic voltammetry and crystal structure, cyano substituents not only lower the LUMO level but also result in a change of the packing mode from the herringbone arrangement to the face-to-face slipped π stacking motif. Then field-effect transistors (FETs) based on high-quality 2-CSB crystals grown by the physical vapor transport method have been fabricated and the highest hole and electron mobilities were measured as 0.66 and 0.29 cm2/Vs, which enhanced the corresponding values of DSB crystal by up to one and two orders of magnitude, respectively. 2-CSB crystal simultaneously combined the high luminescence and the well-balanced mobility is expected to be of interest for the fundamental research of organic light-emitting devices.Cyano substituted distyrylbenzene derivative (2-CSB) crystal has the high luminescence efficiency of ∼55% and well-balanced charge transport characteristics with the hole and electron mobility of 0.66 and 0.29 cm2/Vs, respectively. The introduction of cyano substituents lowers the LUMO level and is efficient to electron injection into 2-CSB. Meanwhile, intermolecular C–H⋯N interactions construct the face-to-face slipped π stacking motif facilitating carrier transport.

Highly Efficient Solid-State Near-Infrared Emitting Material Based on Triphenylamine and Diphenylfumaronitrile with an EQE of 2.58% in Nondoped Organic Light-Emitting Diode

Co-reporter:Xiao Han;Qing Bai;Liang Yao;Haichao Liu;Yu Gao;Jinyu Li;Liqun Liu;Yulong Liu;Xiaoxiao Li;Bing Yang

Advanced Functional Materials 2015 Volume 25( Issue 48) pp:7521-7529

Publication Date(Web):

DOI:10.1002/adfm.201503344

The development of efficient near-infrared (NIR) emitting material is of current focus. Donor–acceptor (D–A) architecture has been proved to be an effective strategy to obtain narrow energy gap. Herein, a D–A-type NIR fluorescent compound 2,3-bis(4′-(diphenylamino)-[1,1′-biphenyl]-4-yl)fumaronitrile (TPATCN) is synthesized and fully characterized. As revealed by theoretical calculations and photophysical experiments, TPATCN exerts the advantages of the relatively large dipole moment of the charge transfer state and a certain degree of orbital overlap of the local excited state. A highly mixed or hybrid local and charge transfer excited state might occur to simultaneously achieve both a large fraction of singlet formation and a high quantum efficiency in D–A system. TPATCN exhibits strong NIR fluorescence with the corresponding thin film quantum efficiency of 33% and the crystal efficiency of 72%. Remarkably, the external quantum efficiency of nondoped NIR organic light-emitting diode (OLED) reaches 2.58% and remains fairly constant over a range of 100–300 mA cm⁻², which is among the best results for NIR OLEDs reported so far.

Efficient Deep Blue Electroluminescence with an External Quantum Efficiency of 6.8% and CIEy 0.08 Based on a Phenanthroimidazole–Sulfone Hybrid Donor–Acceptor Molecule

Co-reporter:Xiangyang Tang, Qing Bai, Qiming Peng, Yu Gao, Jinyu Li, Yulong Liu, Liang Yao, Ping Lu, Bing Yang, and Yuguang Ma

Chemistry of Materials 2015 Volume 27(Issue 20) pp:7050

Publication Date(Web):October 6, 2015

DOI:10.1021/acs.chemmater.5b02685

Tremendous efforts have been devoted to develop efficient deep blue organic light-emitting diodes (OLEDs) materials with CIEy < 0.10 (Commission International de L’Eclairage (CIE)) and match the National Television System Committee (NTSC) standard blue CIE (x, y) coordinates of (0.14, 0.08) for display applications. However, deep blue fluorescent materials with an external quantum efficiency (EQE) over 5% are still rare. Herein, we report a phenanthroimidazole–sulfone hybrid donor–acceptor (D–A) molecule with efficient deep blue emission. D–A structure molecular design has been proven to be an effective strategy to obtain high electroluminescence (EL) efficiency. In general, charge transfer (CT) exciton formed between donor and acceptor is a weak coulomb bonded hole–electron pair and is favorable for the spin flip that can turn triplet excitons into singlet ones. However, the photoluminescence quantum yield (PLQY) of CT exciton is usually very low. On the other hand, a locally excited (LE) state normally possesses high PLQY owing to the almost overlapped orbital distributions. Hence, a highly mixed or hybrid local and charge transfer (HLCT) excited state would be ideal to simultaneously achieve both a large fraction of singlet formation and a high PLQY and eventually achieve high EL efficiency. On the basis of such concept, phenanthroimidazole is chosen as a weak donor and sulfone as a moderate acceptor to construct a D–A type molecule named as PMSO. The PMSO exhibits HLCT excited state properties. The doped device shows deep blue electroluminescence with an emission peak of 445 nm and CIE (0.152, 0.077). The maximum external quantum efficiency (EQE) is 6.8% with small efficiency roll-off. The device performance is among the best results of deep blue OLEDs reported so far.

Isomers of Pyrene–Imidazole Compounds: Synthesis and Configuration Effect on Optical Properties

Co-reporter:Yulong Liu, Tong Shan, Liang Yao, Qing Bai, Yachen Guo, Jinyu Li, Xiao Han, Weijun Li, Zhiming Wang, Bing Yang, Ping Lu, and Yuguang Ma

Organic Letters 2015 Volume 17(Issue 24) pp:6138-6141

Publication Date(Web):December 7, 2015

DOI:10.1021/acs.orglett.5b02879

Two pyrene-imidazole-based structural isomers, axisymmetric syn-PyDTI and centrosymmetric anti-PyDTI, have been easily produced and successfully separated in a one-pot reaction. Crystalline syn-PyDTI exhibited a 2-fold higher quantum efficiency than anti-PyDTI and displayed a much better performance in OLEDs with a ηc.max of 11.4 cd A–1 (8.8 cd A–1 for anti-PyDTI), although they possess the same apparent electronic structure. Observations revealed that the molecular excited-state properties are derived from distinct structural symmetries.

Wide bandgap materials design toward tunable bandgap and increased carries injection property: silane interrupting π-conjugation together with peripheralcarbazolyl substituents

Co-reporter:Dehua Hu, He Liu, Ping Lu, Fangzhong Shen, Ying Lv and Yuguang Ma

RSC Advances 2015 vol. 5(Issue 28) pp:21596-21603

Publication Date(Web):18 Feb 2015

DOI:10.1039/C4RA16797J

A series of wide bandgap materials constructed by silicon-interrupted backbone and non-conjugated carbazole pendants, namely SiPPF, SiPPFCz, SiPF and SiPFCz, are designed and synthesized. Their applications as hosts for triplet emitters in phosphorescent polymer light-emitting diodes (PhPLEDs) are systematically studied. The results show that their photophysical and carries injection properties could be finely tuned by regulating the silicon-confined conjugation length and the peripheral carbazole substituents, respectively. Among them, SiPFCz achieves a compromise of essential demands for ideal electrophosphorescent host materials, such as high triplet energy levels, small barriers for carries injection and homogeneous morphology as well as good miscibility to the dopants. Therefore, the performances of SiPFCz-based devices are superior to devices hosted by SiPPF, SiPPFCz and SiPF, which sheds light on the design strategy of wide bandgap host materials.

Solution-Processable Hosts Constructed by Carbazole/PO Substituted Tetraphenylsilanes for Efficient Blue Electrophosphorescent Devices

Co-reporter:He Liu;Qing Bai;Liang Yao;Dehua Hu;Xiangyang Tang;Fangzhong Shen;Huanhuan Zhang;Yu Gao;Bing Yang ;Yuguang Ma

Advanced Functional Materials 2014 Volume 24( Issue 37) pp:5881-5888

Publication Date(Web):

DOI:10.1002/adfm.201401183

Two new solution-processable wide bandgap materials, bis(4-((4-(9-H-carbazol-9-yl)phenyl)diphenylsilyl)phenyl)(phenyl)phosphine oxide (CS₂PO) and bis(4-((4-(9-H-(3,9′-bicarbazol)-9-yl)phenyl)diphenylsilyl)phenyl)(phenyl)phosphine oxide (DCS₂PO), have been developed for blue phosphorescent light-emitting diodes by coupling an electron-donating carbazole moiety and an electron-accepting PO unit together via double-silicon bridges. Both of them have been characterized as having high glass transition temperatures of 159–199 °C, good solubility in common organic solvent (20 mg mL⁻¹), wide optical gap (3.37–3.55 eV) and high triplet energy levels (2.97–3.04 eV). As compared with their corresponding single-silicon bridged compounds, this design strategy of extending molecular structure endows CS₂PO and DCS₂PO with higher thermal stability, better solution processability and more stable film morphology without lowering their triplet energies. As a result, DCS₂PO/FIrpic doped blue phosphorescent device fabricated by spin-coating method shows the best electroluminescent performance with a maximum current efficiency of 26.5 cd A⁻¹, a maximum power efficiency of 8.66 lm W⁻¹, and a maximum external quantum efficiency of 13.6%, which is one of the highest efficiencies among small molecular devices with the same deposition process and device configuration.

Novel violet emitting material synthesized by stepwise chemical reactions

Co-reporter:Xiangyang Tang, Liang Yao, He Liu, Fangzhong Shen, Shitong Zhang, Yunan Zhang, Huanhuan Zhang, Ping Lu and Yuguang Ma

Journal of Materials Chemistry A 2014 vol. 2(Issue 25) pp:5019-5027

Publication Date(Web):17 Apr 2014

DOI:10.1039/C4TC00456F

In this paper, we report the design and synthesis of a novel bipolar violet emitting molecule CzPySiSF. The carbazole and pyridine moieties are employed to facilitate charge injection and balance carrier transport, whereas the spirofluorene is used as the violet emitter. The three functional groups, i.e., carbazole, pyridine and spirofluorene, are connected to tetraphenylsilane in a stepwise fashion using classical coupling reactions such as Suzuki and Ullmann. The resultant bipolar molecule CzPySiSF exhibits very stable thermal properties and a uniform amorphous morphology. The introduction of spirofluorene greatly enhances the fluorescence quantum efficiency of the molecule; moreover the PL spectrum of CzPySiSF in THF is mainly located in the violet region. The EL spectrum of CzPySiSF matches well with the PL spectrum with a maximum at 408 nm. The violet OLED of CzPySiSF exhibits the maximum external quantum efficiency of 0.59%.

High-efficiency deep blue fluorescent emitters based on phenanthro[9,10-d]imidazole substituted carbazole and their applications in organic light emitting diodes

Co-reporter:Zhao Gao, Zhiming Wang, Tong Shan, Yulong Liu, Fangzhong Shen, Yuyu Pan, Huanhuan Zhang, Xin He, Ping Lu, Bing Yang, Yuguang Ma

Organic Electronics 2014 Volume 15(Issue 11) pp:2667-2676

Publication Date(Web):November 2014

DOI:10.1016/j.orgel.2014.07.019

•A series of highly efficient deep blue emitters are designed and synthesized.•They present narrow FWHM, high quantum yields and high thermal stabilities.•The doped green device with CIE of (0.31, 0.62) and a ηc of 33 cd A−1 is obtained.•The doped white device with CIE of (0.31, 0.31) and a ηc of 5.5 cd A−1 is obtained.A series of highly efficient deep blue emitters comprising of carbazole and phenanthro[9,10-d]imidazole moieties are designed and synthesized. These compounds present deep blue emission, narrow FWHM, high quantum yields, high thermal and morphological stabilities. Among them, the design strategy of 2:1 ratio of phenanthro[9,10-d]imidazole and carbazole unit affords M2 with more balanced carrier injection and transporting properties. OLEDs using M2 as emitting layer is observed to deliver a truly deep blue CIE of y < 0.06 with a highest external quantum efficiency of 3.02%. By taking the full advantage of these deep blue emitters, they are further served as excellent hosts for fluorescent and phosphorescent dyes. High-performance green phosphorescent device based on M2/Ir(ppy)3 is attained with a maximum current efficiency of 33.35 cd A−1, a power efficiency of 22.99 lm W−1 and a maximum external quantum efficiency of 9.47%. When doped with an orange fluorescent material, upon careful tuning the doping proportion, the two-emitting-component white OLED is successfully fabricated with a maximum current efficiency of 5.53 cd A−1 and CIE coordinates of (0.313, 0.305). Both the non-doped and doped devices exhibited high operational stability with negligible efficiency roll-off over the broad current density range.

Microwave-assisted FeCl3-mediated rapid synthesis of poly(9,9-dihexylfluorene) with high molecular weight

Co-reporter:Wensi Zhang, Zhiming Wang, Yunan Zhang, Ping Lu, Linlin Liu, Yuguang Ma

Polymer 2014 Volume 55(Issue 21) pp:5346-5349

Publication Date(Web):9 October 2014

DOI:10.1016/j.polymer.2014.09.001

Poly(9,9-dihexylfluorene) with high molecular weight (Mw ∼ 81,000) is obtained in 25 min using a microwave-assisted FeCl3-mediated oxidative polymerization. The effects of microwave power, time, solvent, monomer and catalyst's concentration on the polymerization have been systematically investigated. The structures and thermal properties of obtained polymers are fully characterized using FTIR, NMR, TGA, DSC, UV–visible absorption and fluorescence spectra. The results show that well-defined polymers have been obtained. XPS, ICP and elemental analysis are used to check the residue of iron catalyst, and almost no residue of FeCl3 is detected in polymers.

An Efficient AIE-Active Blue-Emitting Molecule by Incorporating Multifunctional Groups into Tetraphenylsilane

Co-reporter:Dr. Xiangyang Tang;Dr. Liang Yao;Dr. He Liu;Dr. Fangzhong Shen;Dr. Shitong Zhang;Dr. Huanhuan Zhang; Ping Lu; Yuguang Ma

Chemistry - A European Journal 2014 Volume 20( Issue 25) pp:7589-7592

Publication Date(Web):

DOI:10.1002/chem.201402152

Abstract

A multifunctional AIE-active molecule, CzPySiTPE, in which carbazole (Cz) and pyridine (Py) were attached to tetraphenylsilane to facilitate carrier injection has been designed and synthesized. Tetraphenylethene (TPE) was adopted to maintain efficient blue emission. Blue electroluminescent (EL) emission of CzPySiTPE was obtained with CIE coordinates of (0.16, 0.17) and an external quantum efficiency of 1.12 %.

Separation of Electrical and Optical Energy Gaps: Selectively Adjusting the Electrical and Optical Properties for a Highly Efficient Blue Emitter

Co-reporter:Dr. He Liu;Dr. Ping Chen;Dr. Dehua Hu;Xiangyang Tang;Dr. Yuyu Pan;Huanhuan Zhang;Wenqiang Zhang;Xiao Han;Qing Bai; Ping Lu; Yuguang Ma

Chemistry - A European Journal 2014 Volume 20( Issue 8) pp:2149-2153

Publication Date(Web):

DOI:10.1002/chem.201304544

Abstract

The design concept of separation of optical and electrical bandgap for wide bandgap materials is further developed in DCzSiPI. The HOMO/LUMO levels can be tuned by incorporation of PI and DCz substituents. The tetraphenylsilane core avoids the intramolecular charge transfer from DCz to PI (DCz=dimer carbazole, PI=phenanthro[9,10-d]imidazole). The allowed transitions are found to be from HOMO−1 to LUMO providing DCzSiPI with sufficient bandgap.

Ultrasound-assisted Suzuki coupling reaction for rapid synthesis of polydihexylfluorene

Co-reporter:Xu Gao, Ping Lu, Yuguang Ma

Polymer 2014 Volume 55(Issue 14) pp:3083-3086

Publication Date(Web):19 June 2014

DOI:10.1016/j.polymer.2014.05.036

Ultrasound-assisted synthesis of conjugated polymer is reported taking PF as an example. It is found that ultrasound can dramatically accelerate the Suzuki coupling reaction. The effects of ultrasonic amplitude, time, monomer and catalyst's concentration on the polymerization have been investigated. PF with high Mw of 39,100 g/mol is obtained in 20 min under optimized condition.

Synthesis and Characterization of an Imidazole-Containing Pyrene -System

Co-reporter:Yulong Liu;Zhao Gao;Zhiming Wang;Cunfang Feng;Fangzhong Shen, ;Yuguang Ma

European Journal of Organic Chemistry 2013 Volume 2013( Issue 32) pp:7267-7271

Publication Date(Web):

DOI:10.1002/ejoc.201301285

Abstract

A one-pot reaction is used in the creation of a novel skeleton by using pyrene and the five-membered imidazole ring as the key units. The two new compounds show high thermal stability. Deep-blue emissions are observed in solution for both compounds, which have a strong tendency to aggregate into thin films and a tendency to crystallize as powders. These properties are indicative of their potential application in organic electronic devices.

A triphenylamine-capped solution-processable wholly aromatic organic molecule with electrochemical stability and its potential application in photovoltaic devices

Co-reporter:Zhiming Wang, Xiaohui Song, Lingling Ma, Ying Feng, Cheng Gu, Xiaojuan Zhang, Ping Lu and Yuguang Ma

New Journal of Chemistry 2013 vol. 37(Issue 8) pp:2440-2447

Publication Date(Web):15 May 2013

DOI:10.1039/C3NJ00406F

A triphenylamine-capped solution-processable wholly aromatic conjugated molecule, TPA-TVBP, was designed and synthesized. It exhibited a high thermodynamic stability and good film forming ability as expected, originating from the absence of alkyl and alkoxyl moieties. The triphenylamine cap provided a good solubility because of three-dimensional propeller structure and a donor moiety to construct the organic D–π–A molecule with the electron-deficient tribenzo[a,c,i]phenazine moiety as the acceptor. The special electrochemical stability was discussed through cyclic voltammetry and potential switching step measurements, and the photocurrent generation in photovoltaic device application was described further. Simple bulk heterojunction photovoltaic cells were fabricated using TPA-TVBP and PCBM, and the higher short circuit current and fill factor than the similar structures were achieved. Based on the mechanism of the photocurrent generation, the TPA-TVBP molecule would be a good model molecule to investigate the electrochemical properties of the triphenylamine-capped material in photovoltaic device application.

High-Efficiency Violet-Light-Emitting Materials Based on Phenanthro[9,10-d]imidazole

Co-reporter:Dr. Zhao Gao;Dr. Yulong Liu;Dr. Zhiming Wang ;Dr. Fangzhong Shen;Dr. He Liu;Guannan Sun;Dr. Liang Yao;Dr. Ying Lv; Ping Lu; Yuguang Ma

Chemistry - A European Journal 2013 Volume 19( Issue 8) pp:2602-2605

Publication Date(Web):

DOI:10.1002/chem.201203335

Highly π-extended polymers based on phenanthro-pyrazine: Synthesis, characterization, theoretical calculation and photovoltaic properties

Co-reporter:Zhiming Wang, Zhao Gao, Ying Feng, Yulong Liu, Bing Yang, Dandan Liu, Ying Lv, Ping Lu, Yuguang Ma

Polymer 2013 Volume 54(Issue 22) pp:6191-6199

Publication Date(Web):18 October 2013

DOI:10.1016/j.polymer.2013.09.015

Two novel narrow bandgap conjugated polymers containing phenanthro-pyrazine unit have been successfully synthesized by the Stille coupling reaction. Comparing to the common polymers containing dithiophen-quinoxaline or dithiophen-thieno[3,4-b]pyrazine moiety, the conjugation degree of these new polymers is extended through the direction perpendicular to the main chain by introducing phenanthrene-9,10-dione to maintain a rigid conjugated bridge. The obtained polymers exhibit solution-processing ability, high thermal stabilities, broad visible absorption bands and narrow optical bandgaps. Theoretical studies disclose that the P2 exhibits wholly coplanar conformation in 1-D and 2-D direction, and the PCE value is 6-folded higher than P1 under the same photovoltaic measurement condition.

A Highly Efficient, Blue-Phosphorescent Device Based on a Wide-Bandgap Host/FIrpic: Rational Design of the Carbazole and Phosphine Oxide Moieties on Tetraphenylsilane

Co-reporter:He Liu;Gang Cheng;Dehua Hu;Fangzhong Shen;Ying Lv;Guannan Sun;Bing Yang;Yuguang Ma

Advanced Functional Materials 2012 Volume 22( Issue 13) pp:2830-2836

Publication Date(Web):

DOI:10.1002/adfm.201103126

Abstract

A new series of wide-bandgap materials, 4-dipenylphosphine oxide-4′-9H-carbazol-9-yl-tetraphenylsilane (CSPO), 4-diphenylphosphine oxide-4′,4″-di(9H-carbazol-9-yl)-tetraphenylsilane (pDCSPO), 4-diphenylphosphine oxide -4′-[3-(9H-carbazol-9-yl)-carbazole-9-yl]-tetraphenylsilane (DCSPO), 4-diphenylphosphine oxide-4′,4″,4″′-tri(9H-carbazol-9-yl)-tetraphenylsilane (pTCSPO) and 4-diphenylphosphine oxide -4′-[3,6-di(9H-carbazol-9-yl)-9H-carbazol-9-yl]-tetraphenylsilane (TCSPO), containing different ratios and linking fashions of p-type carbazole units and n-type phosphine oxide units, are designed and obtained. DCSPO is the best host in FIrpic-doped devices for this series of compounds. By utilizing DCzSi and DPOSi as hole- and electron-transporting layers, a high EQE of 27.5% and a maximum current efficiency of 49.4 cd A⁻¹ are achieved in the DCSPO/FIrpic doped device. Even at 10 000 cd m⁻², the efficiencies still remain 41.2 cd A⁻¹ and 23.0%, respectively.

Separation of electrical and optical energy gaps for constructing bipolar organic wide bandgap materials

Co-reporter:Dehua Hu, Fangzhong Shen, He Liu, Ping Lu, Ying Lv, Dandan Liu and Yuguang Ma

Chemical Communications 2012 vol. 48(Issue 24) pp:3015-3017

Publication Date(Web):01 Feb 2012

DOI:10.1039/C2CC17682C

An electrical and optical energy gaps separation strategy is put forward for the design of organic wide bandgap semiconductors. This new principle could achieve optimization of wide bandgap (both high singlet and triplet energies) and favorable carrier injection energy levels simultaneously.

Tuning of the electronic and optical properties of 4,4'-bis(1-phenyl-phenanthro[9,10-d]imidazol-2-yl)biphenyl via cyano substitution in un-conjugated phenyl

Co-reporter:Z. M. Wang, X. H. Song, Z. Gao, D. W. Yu, X. J. Zhang, P. Lu, F. Z. Shen and Y. G. Ma

RSC Advances 2012 vol. 2(Issue 25) pp:9635-9642

Publication Date(Web):10 Aug 2012

DOI:10.1039/C2RA21054A

A new phenanthroimidazole-based material named 4,4'-bis(1-(4-cyano-phenyl)-1H-phenanthro[9,10-d]imidazol-2-yl)biphenyl (CN-BPPI) was prepared by simple one-pot chemical reaction. Its structure and its photophysical, electrochemical and mobility properties were carefully studied. CN-BPPI exhibited similar absorption and emission spectra to BPPI, while the thermal stability and photoluminescence quantum yield were enhanced. More balanced carrier mobility was realized in CN-BPPI due to the substitution of cyano, which was proved by cyclic voltammetry (CV) and single-carriers measurements. The electroluminescence (EL) properties of a blue emitting CN-BPPI device were researched and the EL performances were much better than those for BPPI.

Carbazole/oligocarbazoles substituted silanes as wide bandgap host materials for solution-processable electrophosphorescent devices

Co-reporter:Dehua Hu, Gang Cheng, He Liu, Ying Lv, Ping Lu, Yuguang Ma

Organic Electronics 2012 Volume 13(Issue 12) pp:2825-2831

Publication Date(Web):December 2012

DOI:10.1016/j.orgel.2012.09.010

We have designed and synthesized a series of organic wide bandgap materials, namely DCzSiCz, DDCzSi and DTCzSi, by incorporating carbazole/oligocarbazoles via a silicon-bridged linkage mode. All the materials show good thermal stability and excellent solution-processibility. Their HOMOs and LUMOs could be tuned to facilitate the efficient carriers injection by the incorporated carbazole/oligocarbazoles, while their singlet and triplet energy levels still maintain high levels, all above 3.44 eV and 2.87 eV, respectively. High efficient blue electrophosphorescent devices with low turn-on voltage are realized using DCzSiCz, DDCzSi and DTCzSi as hosts for FIrpic through solution-processable method. Among them, DCzSiCz-based device demonstrates the best performance, showing a maximum brightness of 6600 cd m−2 at 11 V and maximum luminous efficiency of 8.40 cd A−1 at 5 V.Graphical abstractA series of wide bandgap tetraphenyl silane materials by incorporating carbazole/oligocarbazoles via a silicon-bridged linkage mode are designed and synthesized. Their HOMOs and LUMOs could be tuned to facilitate the efficient carriers injection by the incorporated carbazole/oligocarbazoles, while their singlet and triplet energy levels still maintain high levels. Through solution-processable method, DCzSiCz/FIrpic-based device with the maximum luminous efficiency of 8.40 cd A−1 at 5 V is achieved.Highlights► A series of organic wide bandgap tetraphenyl silane materials are designed and synthesized. ► All these materials show excellent solution-processibility and good thermal stability. ► They are suitable as hosts for phosphorescent dye FIrpic. ► High performance solution-processed blue OLEDs are achieved.

Synthesis and characterization of new polyfluorene derivatives: using phenanthro[9,10-d]imidazole group as a building block for deep blue light-emitting polymer

Co-reporter:Zhiming Wang;Zhao Gao;Shanfeng Xue;Yulong Liu;Wensi Zhang;Cheng Gu

Polymer Bulletin 2012 Volume 69( Issue 3) pp:273-289

Publication Date(Web):2012 July

DOI:10.1007/s00289-012-0710-5

A series of novel polyfluorene derivatives P1/4, P2/4, and P3/4, containing phenanthro[9,10-d]imidazole group on backbone are designed, synthesized, and well characterized. They all show high-molecular weights, good solubilities, and excellent thermal stabilities. The CV results of all three compounds show the lower LUMO levels and higher HOMO levels than PF. Among them, P3/4 exhibits deep blue emission both in solution and in solid state. The PLED based on P3/4 shows higher device performance and locates in the deep blue region with a CIE coordinate of (0.17, 0.08).

Peripheral Cyanohexyl Substituent in Wide Bandgap Polymer: Increase the Electron Injection Property for Blue Phosphorescence Light Emitting Device

Co-reporter:Dehua Hu;Gang Cheng;He Liu;Fangzhong Shen;Fenghong Li;Ying Lv;Wenyue Dong;Yuguang Ma

Macromolecular Rapid Communications 2011 Volume 32( Issue 18) pp:1467-1471

Publication Date(Web):

DOI:10.1002/marc.201100179

A solution-processable deep red molecular emitter for non-doped organic red-light-emitting diodes

Co-reporter:Zhiming Wang, Ping Lu, Shanfeng Xue, Cheng Gu, Ying Lv, Qing Zhu, Huan Wang, Yuguang Ma

Dyes and Pigments 2011 Volume 91(Issue 3) pp:356-363

Publication Date(Web):December 2011

DOI:10.1016/j.dyepig.2011.03.034

A new solution-processable deep red emitter, TCTzC, containing dithienylbenzothiadiazole unit and four alkyl-linked peripheral carbazole groups, is designed and synthesized in high yield by Suzuki coupling reaction. The four peripheral carbazole substituents enhance the hole-transport ability, glass transition temperature, decompose temperature and film forming ability of TCTzC. The single-layered device based on TCTzC shows saturated deep red electroluminescence with a CIE coordinate of (0.70, 0.30). The current efficiency and quantum efficiency of TCTzC is two times higher than the compound without the four peripheral carbazole groups. The higher device performance is obtained when TPBi is applied and the external quantum efficiency could reach to 0.93%.Highlights► A deep red emitter TCTzC was obtained. ► It exhibits good amorphous morphology, high Tg and Td. ► Non-doped solution-processable device shows a saturated red emission. ► The EQEmax is 0.93% with a CIE of (0.70, 0.30).

Dual Tuning of Emission Color and Electron Injection Properties Through in-situ Chemical Reaction in a Conjugated Polymer Containing 9,10-Phenanthrenequinone

Co-reporter:Zhiming Wang;Wensi Zhang;Fangzhong Shen;Muddasir Hanif ;Yuguang Ma

Macromolecular Chemistry and Physics 2009 Volume 210( Issue 23) pp:2029-2036

Publication Date(Web):

DOI:10.1002/macp.200900462

Macromol. Chem. Phys. 23/2009

Co-reporter:Zhiming Wang;Wensi Zhang;Fangzhong Shen;Muddasir Hanif ;Yuguang Ma

Macromolecular Chemistry and Physics 2009 Volume 210( Issue 23) pp:

Publication Date(Web):

DOI:10.1002/macp.200990055

The effect of different binding sites on the optical and electronic properties of tetraphenylethylene-substituted thiophene isomers

Co-reporter:Jinyu Li, Tong Shan, Mingming Yao, Yu Gao, Xiao Han, Bing Yang and Ping Lu

Journal of Materials Chemistry A 2017 - vol. 5(Issue 10) pp:NaN2558-2558

Publication Date(Web):2017/02/07

DOI:10.1039/C6TC05653A

Thiophene has attracted tremendous attention in the field of optoelectronics. Here, a series of isomers containing TPE and thiophene are designed and synthesized by Suzuki coupling reactions. TPE groups were attached to the thiophene core at the 2,5-positions (M1), 3,4-positions (M2), 2,3-positions (M3) and 2,4-positions (M4), to endow the resultant molecules with not only various geometries but also high solid-state efficiencies. All the isomers are thermally stable and show good solubility in common organic solvents. They all emit weakly in solution but become strong emitters when fabricated into solid films. Isomer M1 has a more planar space arrangement and exhibits a relatively narrower optical bandgap with respect to the other three isomers. Non-doped OLEDs using the four isomers as light-emitting layers are constructed. M1 gives excellent device performance with a maximum luminance of 65210 cd m−2, a maximum current efficiency of 11.21 cd A−1 and a maximum EQE of 4.49%.

Highly efficient organic light emitting diodes based on a D–A–D type dibenzothiophene derivative exhibiting thermally activated delayed fluorescence with small ΔEST

Co-reporter:Xin He, Tong Shan, Xiangyang Tang, Yu Gao, Jinyu Li, Bing Yang and Ping Lu

Journal of Materials Chemistry A 2016 - vol. 4(Issue 43) pp:NaN10208-10208

Publication Date(Web):2016/10/06

DOI:10.1039/C6TC03382B

A new D–A–D type TADF material, namely DPAC–DBTDO, is constructed using 9,9-diphenyl-9,10-dihydroacridine as an electron donor and dibenzo[b,d]thiophene-5,5-dioxide as an electron acceptor. DPAC–DBTDO possesses a very small ΔEST of 0.10 eV between S1 and T1, which is the lowest value among DBTDO-derivatives. DPAC–DBTDO exhibits nearly 100% solid-state efficiency. A high external quantum efficiency of 13.1% is also achieved in multi-layered OLEDs.

Novel violet emitting material synthesized by stepwise chemical reactions

Co-reporter:Xiangyang Tang, Liang Yao, He Liu, Fangzhong Shen, Shitong Zhang, Yunan Zhang, Huanhuan Zhang, Ping Lu and Yuguang Ma

Journal of Materials Chemistry A 2014 - vol. 2(Issue 25) pp:NaN5027-5027

Publication Date(Web):2014/04/17

DOI:10.1039/C4TC00456F

Separation of electrical and optical energy gaps for constructing bipolar organic wide bandgap materials

Co-reporter:Dehua Hu, Fangzhong Shen, He Liu, Ping Lu, Ying Lv, Dandan Liu and Yuguang Ma

Chemical Communications 2012 - vol. 48(Issue 24) pp:NaN3017-3017

Publication Date(Web):2012/02/01

DOI:10.1039/C2CC17682C

Unique piezochromic fluorescence behavior of organic crystal of carbazole-substituted CNDSB

Co-reporter:Cunfang Feng, Kai Wang, Yuanxiang Xu, Liqun Liu, Bo Zou and Ping Lu