Co-reporter:Liuliu Feng, Jun Yuan, Zhenzhen Zhang, Hongjian Peng, Zhi-Guo Zhang, Shutao Xu, Ye Liu, Yongfang Li, and Yingping Zou
ACS Applied Materials & Interfaces September 20, 2017 Volume 9(Issue 37) pp:31985-31985
Publication Date(Web):August 24, 2017
DOI:10.1021/acsami.7b10995
A novel nonfullerene small molecular acceptor (BZIC) based on a ladder-type thieno[3,2-b]pyrrolo-fused pentacyclic benzotriazole core (dithieno[3,2-b]pyrrolobenzotriazole, BZTP) and end-capped with 1,1-dicyanomethylene-3-indanone (INCN) has been first reported in this work. Through introducing multifused benzotriazole and INCN, BZIC could maintain a high-lying lowest unoccupied molecular orbital (LUMO) energy level of −3.88 eV. Moreover, BZIC shows a low optical bandgap of 1.45 eV with broad and efficient absorption band from 600 to 850 nm due to increased π–π interactions by the covalently locking thiophene and benzotriazole units. A power conversion efficiency of 6.30% is delivered using BZIC as nonfullerene acceptor and our recently synthesized hexafluoroquinoxaline-based polymer HFQx-T as donor. This is the first time to synthesize mutifused benzotriazole-based molecules as nonfullerene electron acceptor up to date. The preliminary results demonstrate that the mutifused benzotriazole derivatives hold great potential for efficient photovoltaics.Keywords: covalently locking; efficient photovoltaics; hexafluoroquinoxaline-based polymer; mutifused benzotriazole; novel nonfullerene acceptor;
Co-reporter:Zhenzhen Zhang;Liuliu Feng;Shutao Xu;Ye Liu;Hongjian Peng;Zhi-Guo Zhang;Yongfang Li;Yingping Zou
Advanced Science 2017 Volume 4(Issue 11) pp:
Publication Date(Web):2017/11/01
DOI:10.1002/advs.201700152
AbstractA new small molecule acceptor, m-ITIC-OR, based on indacenodithieno[3,2-b]thiophene core with meta-alkoxyphenyl side chains, is designed and synthesized. The m-ITIC-OR film shows broader and redshift absorption compared to its solution and matched energy levels with a hexafluoroquinoxaline-based polymer donor-HFQx-T. Here, polymer solar cells (PSCs) by blending an HFQx-T donor and an m-ITIC-OR acceptor as an active layer deliver the power conversion efficiency (PCE) of 6.36% without any posttreatment. The investigations demonstrate that the HFQx-T:m-ITIC-OR blend films possess higher and more balanced charge mobility, negligible bimolecular recombination, and nanoscale interpenetrating morphology after thermal annealing (TA) treatment. Through a simple TA treatment at 150 °C for 5 min, an impressive PCE of 9.3% is obtained. This efficiency is among one of the highest PCEs for additive free PSCs. This is the first time alkoxyphenyl side chain is introduced into nonfullerene electron acceptor; more interestingly, the new electron acceptor (m-ITIC-OR) in this work shows a great potential for highly efficient photovoltaic properties.
Co-reporter:Lixia Qiu, Hongjian Peng, Ye Liu, Beibei Qiu, Zhi-Guo Zhang, Yongfang Li, Yingping Zou
Organic Electronics 2017 Volume 45(Volume 45) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.orgel.2017.02.029
•Two medium bandgap TBF-based polymers are applied in the non-fullerene polymer solar cells.•The polymers/ITIC have good matched complementary absorption, suitable energy level and balanced mobilities.•The PCEs based on polymer/ITIC blend are over 7%.To further investigate non-fullerene polymer solar cells based-thieno[2,3-f]benzofuran (TBF) polymers, we designed and synthesized two medium bandgap TBF-based polymers, namely TBF-BDD and TBF-BT, containing alkoxyphenyl substituted TBF electron-donor unit, 1,3-bis(thiophen-2-yl)-5,7-bis(2-ethylhexyl)benzo-[1,2-c:4,5-c′]dithiophene-4,8-dione (BDD) and 4,7-di(thiophen-2-yl)-5,6-dioctyloxybenzo[c][1,2,5]thiadiazole (BT) electron-acceptor segment, respectively. When blended with ITIC (a n-type small molecule acceptor), two polymer:ITIC blends possess better complementary absorption than the absorption with PC71BM. The properties, including charge mobilities, and morphologies have been intensively investigated. The polymer solar cells based on TBF-BDD:ITIC and TBF-BT:ITIC (1:1,w/w) exhibited promising power conversion efficiencies (PCEs) of 7.13% and 7.03%, respectively, under the illumination of AM 1.5 G, 100 mW/cm2, which are higher in comparison with fullerene-based devices. Up to now, these PCEs are the highest among TBF-based polymer photovoltaic devices.Download high-res image (150KB)Download full-size image
Co-reporter:Lixia Qiu, Jun Yuan, Dingjun He, Zhi-Guo Zhang, Yongfang Li, Yingping Zou
Dyes and Pigments 2017 Volume 140(Volume 140) pp:
Publication Date(Web):1 May 2017
DOI:10.1016/j.dyepig.2017.01.058
•The synthesis of two medium bandgap, alkoxyphenyl and alkoxyl substituted thieno[2,3-f]benzofuran (TBF)-based polymers.•Good solubility, broad absorption, balanced mobility and continuous interpenetrating morphology.•The highest PCE of 6.58% for PTBFPO-BDD based OPVs without any treatment.Two new medium bandgap, alkoxyphenyl substituted thieno[2,3-f]benzofuran (TBFPO) and alkoxyl substituted thieno[2,3-f]benzofuran (TBFP)-based polymers were designed, synthesized and applied in polymer solar cells (PSCs), namely, TBFPO-BDD and TBFO-BDD, respectively. Their thermal, optical, electronic properties and photovoltaic performances were systematically investigated. The PSCs prepared using o-dichlorobenzene as solvent, with the single layer device structure of ITO/PEDOT:PSS/TBFPO-BDD:PC71BM (1:1; w/w)/perylene diimide (PDI) derivative (PDINO)/Al, exhibited a promising power conversion efficiency (PCE) of 6.58% under the illumination of AM 1.5G, 100 mW/cm2, without any post-treatment. While the devices based on TBFO-BDD showed an enhanced PCE of 3.07% with 1 vol% 1,8-diodooctane (DIO) as additive. This study demonstrates that TBFPO-BDD is a promising polymer for organic electronics.Download high-res image (164KB)Download full-size image
Co-reporter:Ling Fan, Guohui Chen, Lihui Jiang, Jun Yuan, Yingping Zou
Chemical Physics 2017 Volume 493(Volume 493) pp:
Publication Date(Web):17 August 2017
DOI:10.1016/j.chemphys.2017.06.007
•Three small molecules named BDTDPP, TBFDPP and BDFDPP are synthesized and charcterized.•With 0.3% DIO, PCEs reach 3.9%, 3.7% and 3.4% for BDTDPP, TBFDPP and BDFDPP.•Investigations show that BDC units have advantages in high efficiency optoelectronic materials.Three small molecules named BDTDPP, TBFDPP and BDFDPP are designed and synthesized with alkoxy-substituted benzodichalcogenophene derivatives as donor unit while diketopyrrolopyrrole unit as acceptor unit, the investigation results show that all three small molecular materials possess favorable solubility, excellent thermal stability, broad absorption spectra and suitable electrochemical energy level. The bulk heterojunction devices based on these three small molecular materials show the power conversion efficiencies up to 3.19%, 2.82% and 2.81%, respectively. When adding 0.3% (v/v) 1,8-diiodooctane as additives, the power conversion efficiencies were further improved to 3.95%, 3.72% and 3.41%, respectively. The investigations show that all three benzodichalcogenophene-diketopyrrolopyrrole derivatives have great potential in the design of high performance optoelectronic materials.
Co-reporter:Tao Wang;Lihui Jiang;Jun Yuan;Liuliu Feng;Zhi-Guo Zhang;Jiannan Xiang;Yongfang Li;Yingping Zou
Polymer Chemistry (2010-Present) 2017 vol. 8(Issue 14) pp:2227-2234
Publication Date(Web):2017/04/04
DOI:10.1039/C7PY00349H
In order to improve the photovoltaic performance of pyrido[3,4-b]pyrazine (PP)-based polymers, a new fluoropyrido[3,4-b]pyrazine based D–A type polymer (BDT-S-fPP) was synthesized. The optical, electrochemical and photovoltaic properties were well investigated. A power conversion efficiency (PCE) over 6.0% with a single junction device was obtained, which is the highest PCE among the PP-based polymers reported to date.
Co-reporter:Hongjian Peng;Xiangfeng Luan;Liuliu Feng;Jun Yuan;Zhi-Guo Zhang;Yongfang Li;Yingping Zou
Physical Chemistry Chemical Physics 2017 vol. 19(Issue 22) pp:14289-14295
Publication Date(Web):2017/06/07
DOI:10.1039/C7CP02283B
Ladder-type conjugated structures with rigid and coplanar molecular frameworks feature longer effective conjugation, affirmative optoelectronic properties and strong intermolecular π–π interactions, which are ideal characteristics for organic photovoltaics. Here, a new “zigzag” angular-fused naphthodifuran (zNDF) based on alkoxyphenyl side chains was designed and synthesized. The distannylated zNDF building block was copolymerized with 4,7-di(5-bromothiophen-2-yl)-5,6-dioctyloxybenzo[c][1,2,5]thiadiazole and 5,8-bis(5-bromothiophen-2-yl)-2,3-bis(4-(2-ethylhexyloxy)-3-fluorophenyl)-6,7-difloroquinoxaline (Br-BT and Br-ffQx) acceptor units by Stille cross coupling reaction to form two new medium bandgap donor–acceptor polymers PzNDFP-BT and PzNDFP-ffQx, respectively. The photovoltaic properties of the copolymers blended with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as an electron acceptor were investigated. A 6.9% efficiency was achieved from the single device based on the PzNDFP-BT : PC71BM (1 : 1.5, w/w) blend film with a 0.25% 1,8-diiodooctane (DIO) additive, which is among the highest efficiency for zNDF-based polymer solar cells.
Co-reporter:Jun Yuan;Jianyong Ouyang;Věra Cimrová;Mario Leclerc;Ahmed Najari;Yingping Zou
Journal of Materials Chemistry C 2017 vol. 5(Issue 8) pp:1858-1879
Publication Date(Web):2017/02/23
DOI:10.1039/C6TC05381E
Polymer solar cells (PSCs) with a bulk heterojunction (BHJ) structure, i.e. a blend of a p-type conjugated polymer with an n-type semiconductor acceptor, have made rapid progress over the past decade. In comparison with inorganic semiconductor solar cells, PSCs have the advantages of low cost, light weight, solution processability and good mechanical flexibility. In the last few years, various classes of electron-donating polymers have been reported for PSCs. Among them, quinoxaline (Qx) and its derivatives have been widely used as building blocks for optoelectronic applications because they can be easily modified by varying the side chains, such as alkyl chains, conjugated aromatic rings, functional groups, etc. Recently, a power conversion efficiency (PCE) of over 11% was achieved for PSCs with Qx-based polymers. This PCE is among the best for PSCs, and it suggests that Qx-based polymers have great potential for highly efficient PSCs. In this article, we review the recent advances in the design and synthesis of such Qx-based conjugated polymers for photovoltaic applications. Particular attention is paid to the chemical structures of the polymers including flexible chains, conjugated side chains, functional groups, Qx derivatives and the effect of the molecular structure on device performance parameters. We believe that further development of Qx-based polymers will lead to a PCE >12% in the near future.
Co-reporter:Zhenzhen Zhang;Liuliu Feng;Shutao Xu;Jun Yuan;Zhi-Guo Zhang;Hongjian Peng;Yongfang Li;Yingping Zou
Journal of Materials Chemistry A 2017 vol. 5(Issue 22) pp:11286-11293
Publication Date(Web):2017/06/06
DOI:10.1039/C7TA02486J
A new small molecule, ITTC, bearing an indacenodithieno[3,2-b]thiophene core and a 2-(6-oxo-5,6-dihydro-4H-cyclopenta[c]thiophen-4-ylidene)malononitrile end group, was designed, synthesized and characterized as a non-fullerene electron acceptor. The ITTC possesses strong and broad light absorption, high and balanced charge mobility and a nanoscale interpenetrating morphology when blended with a recently synthesized hexafluoroquinoxaline based polymer donor-HFQx-T. HFQx-T was obtained from a Stille coupling copolymerization of a 2,6-bis(trimethyltin)-4,8-bis(5-(2-ethylhexyl)thiophene-2-yl)benzo[1,2-b:4,5-b′]dithiophene electron donating unit and a hexafluoroquinoxaline based electron accepting unit. The device employing HFQx-T as the donor and ITTC as the acceptor delivered a power conversion efficiency (PCE) of 8.19% without any post-treatment. After thermal annealing, an impressive PCE of 10.4% was obtained. This performance is among the highest PCEs reported for fullerene-free polymer solar cells up to date. This study demonstrates the great potential of ITTC as n-type materials for organic electronics.
Co-reporter:Shutao Xu, Liuliu Feng, Jun Yuan, Věra Cimrová, Guohui Chen, Zhi-Guo Zhang, Yongfang Li, Hongjian Peng, Yingping Zou
Organic Electronics 2017 Volume 50(Volume 50) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.orgel.2017.07.005
•Two D-A copolymers, named OFQx-T and EHFQx-T, are designed and synthesized.•Replacing octyloxy chain with ethylhexyloxy group in DFQx based system can improve the absorption coefficient, reduce the geminate recombination and achieve higher charge mobility and more balanced μh/μe.•A higher PCE of 8.44% was obtained in EHFQx-T:PC71BM device (1:1.5, w:w) compared to a PCE of 7.60% in OFQx-T:PC71BM based device (1:1.5, w:w) after DIO treatment.Two new donor (D) - acceptor (A) copolymers, named m-O-p-F-DFQx-BDT (OFQx-T) and m-EH-p-F-DFQx-BDT (EHFQx-T), which were based on meta-octyloxy-para-fluorophenyl and meta-ethylhexyloxy-para-fluorophenyl difluoroquinoxaline as acceptor units (O-DFQx/EH-DFQx) and alkylthienyl substituted benzodithiophene (BDT) as a donor unit, were designed and synthesized. EHFQx-T had higher absorption coefficient than OFQx-T which contributed to larger short-circuit current density (Jsc). EHFQx-T showed a lower the highest occupied molecular orbital (HOMO) which is beneficial for the voltage open-circuit (Voc). The polymer solar cells (PSCs) based OFQx-T:PC71BM and EHFQx-T:PC71BM blended film as active layer showed high power conversion efficiency (PCE) of 7.60% and 8.44%, respectively, with 1,8-diiodooctane (DIO) solvent additive treatment. More importantly, OFQx-T:PC71BM and EHFQx-T:PC71BM had good fill factor (FF), especially the FF of OFQx-T:PC71BM was over 70%. The high FF contributed to obtain high PCEs for OFQx-T and EHFQx-T. The more balanced and higher charge mobility, smaller geminate recombination and suitable nanoscale phase separation size of EHFQx-T demonstrate that changing octyl chain to ethylhexyl chain in DFQx acceptor unit is efficient to improve photovoltaic properties in fullerene solar cells.Download high-res image (197KB)Download full-size image
Co-reporter:Hongjian Peng, Xiangfeng Luan, Lixia Qiu, Hang Li, Ye Liu, Yingping Zou
Optical Materials 2017 Volume 72(Volume 72) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.optmat.2017.05.048
•Two new A–D–A naphtho[1,2-b:5,6‑b′]difuran (NDF) based small molecules, were synthesized.•The effects of the alkoxyphenyl and alkylthiophenyl side chains on the NDF unit have been investigated.•The best PCE values of OSCs based on NDFPO-DPP:PC71BM (1.3:1) and NDFPS-DPP:PC71BM (1.3:1) are 3.10 % and 3.04 %.Two new A–D–A small molecules with alkoxyphenyl and alkylthiophenyl-substituted naphtho[1,2-b:5,6-b′]difuran (NDF) as the central building block named NDFPO-DPP and NDFPS-DPP were synthesized and firstly used as donor materials in organic solar cells (OSCs). The effects of the alkoxyphenyl and alkylthiophenyl side chains on the NDF unit have been investigated. With a single atom variation from O to S, NDFPS-DPP exhibited lower HOMO energy levels than its counterpart NDFPO-DPP, which resulted in enhanced Voc. The device based on NDFPO-DPP with thermal annealing exhibited a better PCE of 3.10% due to the higher and more balanced hole and electron mobilities. The investigations show that NDF could be a promising building block in OSCs via rational molecular structure design and device optimizations.
Co-reporter:Jun Yuan, Lixia Qiu, Zhiguo Zhang, Yongfang Li, Yuehui He, Lihui Jiang and Yingping Zou
Chemical Communications 2016 vol. 52(Issue 42) pp:6881-6884
Publication Date(Web):18 Mar 2016
DOI:10.1039/C6CC01771A
A new tetrafluoridequinoxaline electron accepting block from a quinoxaline core, which is substituted with a fluorine atom onto its backbone and side chains, was designed. A new copolymer (PBDTT-ffQx) was synthesized from tetrafluoridequinoxaline and benzodithiophene. The copolymer was characterized in detail. The photovoltaic properties were well investigated. A high PCE of 8.6% based on the single junction device was obtained.
Co-reporter:Jun Yuan, Lixia Qiu, Shutao Xu, Zhiguo Zhang, Yongfang Li, Yingping Zou
Organic Electronics 2016 Volume 37() pp:287-293
Publication Date(Web):October 2016
DOI:10.1016/j.orgel.2016.07.007
•A series of new copolymers from tetrafluoridequinoxaline (ffQx) and three distinctive phenyl substituted benzodithiophene were synthesized.•All the PSCs with the ffQx-based polymers as donor exhibited VocS higher than 0.9 V and power conversion efficiencies over 7%.•PffQx-PS has a lower bimolecular recombination and deeper HOMO energy level, which contributes to the higher fill factor and higher open-circuit voltage.A series of new copolymers from tetrafluoridequinoxaline (ffQx) and three distinctive phenyl (alkoxy-1-meta-fluorophenyl, alkoxyphenyl and alkylthiophenyl) substituted benzodithiophene (BDT), namely, PffQx-m-fPO, PffQx-PO and PffQx-PS, were designed and synthesized. Photophysical properties, charge mobilities and morphologies of the three polymers have been intensively investigated. Benefitted from the effects of phenyl and fluorine substituents on the backbone, all the polymers possess deep the highest occupied molecular orbital (HOMO) levels. In particular, PffQx-PS has a lower bimolecular recombination and deeper HOMO energy level, which contributes to the higher fill factor (FF, ca. 70%) and higher open-circuit voltage (Voc, ca. 0.93 V) of the polymer solar cells (PSCs) with the polymer as donor and PC71BM as acceptor. All the PSCs with the ffQx-based polymers as donor exhibited VocS higher than 0.9 V and power conversion efficiencies over 7% (7.0% for PffQx-m-fPO, 7.4% for PffQx-PO and 8.0% for PffQx-PS).A series of new copolymers from tetrafluoridequinoxaline (ffQx) and three distinctive phenyl substituted benzodithiophene were synthesized. All the PSCs with the ffQx-based polymers as donor exhibited VocS higher than 0.9 V and power conversion efficiencies over 7%.
Co-reporter:Beibei Qiu, Jun Yuan, Yingping Zou, Dingjun He, Hongjian Peng, Yongfang Li, Zhiguo Zhang
Organic Electronics 2016 Volume 35() pp:87-94
Publication Date(Web):August 2016
DOI:10.1016/j.orgel.2016.05.010
•An asymmetric small molecule R3T-TBFO was designed and synthesized.•R3T-TBFO film showed a wide absorption range from 300 nm to 763 nm, with a low optical bandgap of 1.63 eV.•The device with TA + SVA treatment presented a better balanced hole- and electron-mobility.•The TA + SVA based device exhibited a PCE of 6.32%, with a high FF of 0.72.A new asymmetric small molecule, named R3T-TBFO, with 4,8-bis(2-ethylhexyloxy)-substituted thieno[2,3-f]benzofuran (TBF) as central donor block, has been synthesized and used as donor material in organic solar cells (OSCs). With thermal annealing (TA) and solvent vapor annealing (SVA) treatment, the blend of R3T-TBFO/PC71BM shows a higher hole mobility of 1.37 × 10−4 cm2 V−1 s−1 and a more balanced charge mobilities. Using a structure of ITO/PEDOT:PSS/R3T-TBFO:PC71BM/ZrAcac/Al, the device with TA treatment delivered a moderate power conversion efficiency (PCE) of 5.63%, while device after TA + SVA treatment showed a preferable PCE of 6.32% with a high fill factor (FF) of 0.72.
Co-reporter:Beibei Qiu, Jun Yuan, Xuxian Xiao, Dingjun He, Lixia Qiu, Yingping Zou, Zhi-guo Zhang, and Yongfang Li
ACS Applied Materials & Interfaces 2015 Volume 7(Issue 45) pp:25237
Publication Date(Web):October 30, 2015
DOI:10.1021/acsami.5b07066
Two new small molecules, C3T-BDTP and C3T-BDTP-F with alkoxyphenyl-substituted benzo[1,2-b:4,5-b′]dithiophene (BDT) and meta-fluorinated-alkoxyphenyl-substituted BDT as the central donor blocks, respectively, have been synthesized and used as donor materials in organic solar cells (OSCs). With the addition of 0.4% v/v 1,8-diiodooctane (DIO), the blend of C3T-BDTP-F/PC71BM showed a higher hole mobility of 8.67 × 10–4 cm2 V–1 s–1 compared to that of the blend of C3T-BDTP/PC71BM. Two types of interlayers, zirconium acetylacetonate (ZrAcac) and perylene diimide (PDI) derivatives (PDINO and PDIN), were used to further optimize the performance of OSCs. With a device structure of ITO/PEDOT:PSS/donor:PC71BM/PDIN/Al, the OSCs based on C3T-BDTP delivered a satisfying power conversion efficiency (PCE) of 5.27% with an open circuit voltage (Voc) of 0.91 V, whereas the devices based on C3T-BDTP-F showed an enhanced PCE of 5.42% with a higher Voc of 0.97 V.Keywords: alkoxyphenyl; interlayer; meta-fluorinated-alkoxyphenyl; organic solar cells; small molecule photovoltaic materials
Co-reporter:Ling Fan, Ruili Cui, Lihui Jiang, Yingping Zou, Yongfang Li, Dong Qian
Dyes and Pigments 2015 Volume 113() pp:458-464
Publication Date(Web):February 2015
DOI:10.1016/j.dyepig.2014.08.027
•A small molecule (TIBDT) with indolone chromophore as electron acceptor unit was synthesized.•TIBDT was well characterized and first applied in organic solar cells (OSCs).•TIBDT demonstrates a power conversion efficiency of 3.94% with high Voc up to 0.89 V and FF of 0.60.A new small molecule (TIBDT) with indolone chromophore as the electron acceptor unit and benzodithiophene as electron donor unit was synthesized and first applied in organic solar cells (OSCs). TIBDT was characterized by NMR, TGA, UV–Vis absorption spectroscopy and cyclic voltammetry measurements. Results show that TIBDT possesses excellent thermal stability, appropriate absorption spectra, low-lying highest occupied molecular orbital (HOMO) level and high hole mobility. The OSCs based on TIBDT: PC71BM (1:1, w/w) showed a power conversion efficiency (PCE) up to 3.94% with an open circuit voltage (Voc) of 0.89 V, short circuit current (Jsc) of 7.36 mA cm−2, fill factor (FF) of 60.2% under the illumination of AM 1.5 G, 100 mW cm−2 without solvent additives and thermal annealing treatment. These preliminary investigations show that indolone chromophore can probably be an excellent electron accepting unit for constructing high performance optoelectronic materials.
Co-reporter:Ruili Cui, Yingping Zou, Lu Xiao, Chain-Shu Hsu, Mukhamed L. Keshtov, Dmitri Yu. Godovsky, Yongfang Li
Dyes and Pigments 2015 Volume 116() pp:139-145
Publication Date(Web):May 2015
DOI:10.1016/j.dyepig.2015.01.021
•A new D-A copolymer, TBFBT, was synthesized and characterized.•PSCs based on TBFBT:PC71BM exhibited a high PCE up to 6.1% by using methanol treatment.•Improved photovoltaic properties using methanol treatment are accountable to increased mobility and better film morphology.A new conjugated D-A copolymer, TBFBT, containing a fluorinated benzothiazole electron-acceptor unit and an electron-donor segment of alkylthienyl substituted thieno[2,3-f]benzofuran, was synthesized using a Stille coupling reaction. The resulting copolymer was characterized by elemental analysis, GPC, TGA, UV–Vis absorption spectroscopy and cyclic voltammetry measurements. The copolymer was readily dissolved in common organic solvents, exhibited good film forming properties and displayed a broad absorption from 300 nm to 800 nm with a low optical bandgap of 1.56 eV. Cyclic voltammetry measurement gave HOMO and LUMO energy levels of −5.11 eV and −3.49 eV, respectively. Polymer solar cells based on TBFBT: PC61BM (1:1.5, w/w) demonstrated an initial power conversion efficiency (PCE) of 4.1% with a Voc of 0.72 V and a Jsc of 11.6 mA cm−2. PSCs based on TBFBT:PC71BM (1:1.5, w/w, 3 vol% 1,8-diiodooctane as additive) were further optimized by using methanol. The optimized result exhibited a high PCE up to 6.1% with a high Jsc of 14.4 mA cm−2 and FF of 0.62, under the illumination of AM1.5G, 100 mWcm−2. These investigations indicate that the new copolymer TBFBT is a promising donor material for PSCs and methanol treatment is a simple and effective way to improve PCE.
Co-reporter:Beibei Qiu, Ruili Cui, Jun Yuan, Hongjian Peng, Zhiguo Zhang, Yongfang Li and Yingping Zou
Physical Chemistry Chemical Physics 2015 vol. 17(Issue 27) pp:17592-17600
Publication Date(Web):13 May 2015
DOI:10.1039/C5CP02127H
Two new alkoxylphenyl substituted thieno[2,3-f]benzofuran (TBFP)-based polymers (PTBFP–BT and PTBFP–BO) were designed and synthesized. Their structures were verified by nuclear magnetic resonance (NMR) spectroscopy, the molecular weights were determined by gel permeation chromatography (GPC) and the thermal properties were investigated by thermogravimetric analysis (TGA). The two polymers showed similar UV-Vis absorption spectra with a broad and strong absorption band from 300–750 nm in solid state. The resulting copolymers exhibited relatively deep highest occupied molecular orbital (HOMO) energy levels (−5.47 and −5.61 eV) for PTBFP–BT and PTBFP–BO, respectively. The device fabricated with PTBFP–BT:PC71BM (1:2) showed better balanced hole and electron mobility of 2.49 × 10−4 cm2 V−1 s−1 and 9.12 × 10−4 cm2 V−1 s−1, respectively, than those of PTBFP–BO based devices. The polymer solar cells (PSCs), based on the single layer device structure of ITO/PEDOT:PSS/PTBFP–BT:PC71BM (1:2, w/w)/ZrAcac/Al with 3 vol% 1,8-diiodooctane (DIO) as additive, showed a relatively high power conversion efficiency (PCE) of 6% under the illumination of AM 1.5G, 100 mW cm−2, with a high fill factor (FF) of 0.69.
Co-reporter:Ruili Cui, Ling Fan, Jun Yuan, Lihui Jiang, Guohui Chen, Yanhuai Ding, Ping Shen, Yongfang Li and Yingping Zou
RSC Advances 2015 vol. 5(Issue 38) pp:30145-30152
Publication Date(Web):16 Mar 2015
DOI:10.1039/C5RA03405A
In order to shed light on the effects of different numbers of fluorine atoms in donor–acceptor (D–A) conjugated polymers on the photophysics and photovoltaic properties, three polymers named PTBFBT-0F, PTBFBT-1F, PTBFBT-2F were synthesized and thoroughly investigated. The nonfluorinated benzothiadiazole (BT) polymer (PTBFBT-0F) has a highest occupied molecular orbital (HOMO) energy level of −4.98 eV and a low bandgap of 1.64 eV. When one of the hydrogen atoms of the BT unit was substituted by a fluorine atom (PTBFBT-1F), a small blue-shift in UV-Vis absorption and a lower HOMO energy level of −5.11 eV were observed, thus a similar Voc and Jsc were obtained. Nevertheless, the FF of PTBFBT-2F was further improved from 46% to 53% due to the relatively higher and balanced electron/hole charge transport mobility of 1.83 × 10−5 cm2 V−1 s−1 and 1.52 × 10−5 cm2 V−1 s−1. Using a Ca/Al top electrode, devices based on PTBFBT-0F, PTBFBT-1F, PTBFBT-2F as electron donor showed increasing power conversion efficiencies (PCE) of 3.0%, 3.6% and 4.2%, respectively. Furthermore, replacing Ca with a zirconium acetylacetonate film (ZrAcac) as the cathode buffer layer (CBL), a PCE of 5% with PTBFBT-2F as the donor was obtained.
Co-reporter:Jun Yuan, Yingping Zou, Ruili Cui, Yi-Hsiang Chao, Zaiyu Wang, Mingchao Ma, Yuehui He, Yongfang Li, Amanda Rindgen, Wei Ma, Dequan Xiao, Zhishan Bo, Xinjun Xu, Lidong Li, and Chain-Shu Hsu
Macromolecules 2015 Volume 48(Issue 13) pp:4347-4356
Publication Date(Web):July 2, 2015
DOI:10.1021/acs.macromol.5b00564
We have designed and synthesized two low bandgap conjugated copolymers containing alternating meta-fluoro-p-alkoxyphenyl- (m-FPO-) or p-fluoro-m-alkoxyphenyl- (p-FPO-) substituted benzodithiophenes-co-benzooxadiazole (BO), named PBO-m-FPO and PBO-p-FPO. The properties, including UV–vis absorption, charge mobility and photovoltaic performance of the two polymers have been intensively investigated. The results indicated that the introduction of fluorine atom at m, p positions of phenyl substituted benzodithiophene unit hardly affected their absorption spectra and highest occupied molecular orbital (HOMO) level. However, the two polymers showed different photovoltaic properties. Power conversion efficiencies (PCEs) based on the device structure of ITO/PEDOT:PSS/polymer:PC71BM/Ca/Al demonstrated a large distinction (5.9% for PBO-m-FPO vs 2.8% for PBO-p-FPO) at optimal weight ratio. When replacing the Ca layer with zirconium acetylacetonate (ZrAcac), using 3% 1,8-diiodooctane (DIO) as the active layer additive, the PCEs of PBO-m-FPO and PBO-p-FPO increased by 36% (8.0% vs 5.9%) and 85% (5.1% vs 2.8%), respectively. The active layer’s mobilities, morphology and molecular packing resulted in a significant difference in short-circuit current density (Jsc) and fill factor (FF).
Co-reporter:Ling Fan, Ruili Cui, Xiuping Guo, Dong Qian, Beibei Qiu, Jun Yuan, Yongfang Li, Wenlong Huang, Junliang Yang, Weifang Liu, Xinjun Xu, Lidong Li and Yingping Zou
Journal of Materials Chemistry A 2014 vol. 2(Issue 28) pp:5651-5659
Publication Date(Web):23 May 2014
DOI:10.1039/C4TC00738G
A new alkylthienyl substituted thieno[2,3-f]benzofuran (TBF)-based polymer (PTBFTDTBT) was synthesized and characterized. PTBFTDTBT had a high molecular weight, good solubility in common organic solvents, broad visible absorption from 300 to 750 nm, and a relatively deep highest occupied molecular orbital level (−5.2 eV). PTBFTDTBT also showed a field hole mobility up to the order of 10−2 using an organic field effect transistor (OFET) method and an order of 10−2 using a space-charge-limited current (SCLC) method. With the structure of indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):polystyrene sulfonate/PTBFTDTBT:PC71BM (1:2, w/w)/Ca/Al, a power conversion efficiency of 6.42% was obtained with a high short circuit current (Jsc) of 13.51 mA cm−2 and fill factor (FF) of 61%, under the illumination of AM1.5G, at 100 mW cm−2, without any post-treatment. The study demonstrates that TBF is a promising building block for organic electronics.
Co-reporter:Bo Liu, Beibei Qiu, Xuewen Chen, Lu Xiao, Yongfang Li, Yuehui He, Lihui Jiang and Yingping Zou
Polymer Chemistry 2014 vol. 5(Issue 17) pp:5002-5008
Publication Date(Web):02 May 2014
DOI:10.1039/C4PY00392F
A new low bandgap D–A copolymer PBDFTDTBT containing 4,8-bis(2-(2-ethylhexyl)thiophen-2-yl)-benzo[1,2-b;3,4-b′]difuran (BDFT) and 4,7-di(thiophen-2-yl)-5,6-dioctyloxybenzo[c][1,2,5]thiadiazole (DTBT) units was synthesized and characterized for application as a donor material in polymer solar cells (PSCs). The PBDFTDTBT film showed a broad absorption band from 300 nm to around 730 nm in the visible light region and the hole mobility of the blend of PBDFTDTBT and PC71BM reached up to 0.36 cm2 V−1 s−1 by using the space charge limited current (SCLC) method. The PSCs based on PBDFTDTBT:PC71BM (1:1.5, w/w) exhibited a promising power conversion efficiency (PCE) of 6.0% under the illumination of AM 1.5 G, 100 mW cm−2 with a high short circuit current density (Jsc) of 12.04 mA cm−2 and an open circuit voltage (Voc) of 0.76 V.
Co-reporter:Wenlong Huang, Bingchu Yang, Jia Sun, Bo Liu, Junliang Yang, Yingping Zou, Jian Xiong, Conghua Zhou, Yongli Gao
Organic Electronics 2014 Volume 15(Issue 5) pp:1050-1055
Publication Date(Web):May 2014
DOI:10.1016/j.orgel.2014.02.020
•PBDFTDTBT is a benzo[1,2-b:4,5-b′]difuran-based donor–acceptor (D–A) conjugated polymer.•PBDFTDTBT is used to fabricate organic field-effect transistors (OFETs) with good performance.•PBDFTDTBT OFETs show a hole mobility of 0.05 cm2/Vs and an on/off ratio of 4.6 × 105.•OFETs have a photosensitivity (Ilight/Idark) of 1.2 × 105 under white light illumination.•PBDFTDTBT OFETs are very stable and have no obvious degeneration for 3 months in air.Organic field-effect transistors (OFETs) were fabricated through a solution process with a donor–acceptor (D–A) conjugated polymer poly{4,8-bis(2′-ethylhexylthiophene)benzo [1,2-b;3,4-b′]difuran-alt-5,5-(4′,7′-di-2-thienyl-5′,6′-dioctyloxy-2′,1′,3′-benzothiadiazole)} (PBDFTDTBT) as the active layer, which is a highly efficient D–A conjugated polymer as a donor in polymer solar cells with a power conversion efficiency (PCE) over 6.0%. The OFET devices showed a hole mobility of 0.05 cm2/Vs and an on/off ratio of 4.6 × 105. Those are one of the best performance parameters for OFETs based on D–A conjugated polymers including benzo[1,2-b:4,5-b′]dithiophene (BDT) or benzo[1,2-b:4,5-b′]difuran (BDF) unit. The photoresponse of OFETs was investigated by modulating light with various intensities. The devices produced a photosensitivity (Ilight/Idark) of 1.2 × 105 and a photoresponsivity of 360 mA W−1 under white light illumination. The drain current in saturation region increases gradually with increasing illumination intensity. The threshold voltage exhibited a positive shift from −15.6 V in darkness to 27.8 V under illumination, which can be attributed to the well-known photovoltaic effect resulting from the transport of photogenerated holes and trapping of photogenerated electrons near the source electrode in organic phototransistors. Meanwhile, the devices showed good stability and with no obvious degeneration for 3 months in air. The study suggests that D–A conjugated polymers including BDF unit can be potentially applied in OFETs and organic phototransistors in addition to highly efficient polymer solar cells.Graphical abstract
Co-reporter:Lu Xiao, Jun Yuan, Yingping Zou, Bo Liu, Jinzhi Jiang, Yan Wang, Lihui Jiang, Yong fang Li
Synthetic Metals 2014 Volume 187() pp:201-208
Publication Date(Web):January 2014
DOI:10.1016/j.synthmet.2013.11.009
A new donor–acceptor conjugated polymer (PBDTPO-FBT), which consists of a fluorinated benzothiadiazole (FBT) electron-acceptor unit and an electron-donor segment of alkoxylphenyl substituted benzo[1,2-b:4,5-b′]dithiophene (BDTPO), was synthesized according to the Stille cross-coupling reaction. The resulting copolymer was characterized by TGA, GPC, UV–vis absorption spectroscopy and cyclic voltammetry measurements. PBDTPO-FBT possesses good thermal stability with 5% weight loss temperature of 410 °C and shows broad absorption at 300–800 nm with an optical bandgap of 1.53 eV. Cyclic voltammetry measurement exhibits HOMO and LUMO energy levels of −5.43 eV and −3.72 eV, respectively. The hole mobility of PBDTPO-FBT:PC71BM (1:1, w/w) reaches up to 3.8 × 10−3 cm2/V/s by the space-charge-limited current (SCLC) method. By using 3% 1,8-diiodooctane (DIO) as the solvent additive, the polymer solar cell with the configuration of ITO/PEDOT:PSS/PBDTPO-FBT:PC71BM (1:1, w/w)/Ca/Al demonstrates a power conversion efficiency of 2.70% with Voc = 0.70 V, Jsc = 7.23 mA/cm2 and FF = 47.08%, under the illumination of AM 1.5 G, 100 mW/cm2.
Co-reporter:Bo Liu, Xuewen Chen, Yuehui He, Yongfang Li, Xinjun Xu, Lu Xiao, Lidong Li and Yingping Zou
Journal of Materials Chemistry A 2013 vol. 1(Issue 3) pp:570-577
Publication Date(Web):16 Oct 2012
DOI:10.1039/C2TA00474G
Three new alkylthienyl substituted benzodithiophene (BDT)-based polymers, poly{4,8-bis(2′-ethylhexylthiophene)benzo[1,2-b;3,4-b′]dithiophene-alt-5,5-(4′,7′-di-2-thienyl-5′,6′-dioctyloxy-benzo[c][1,2,5]oxadiazole)}(PBDTTDTBO), poly{4,8-bis(2′-ethylhexylthiophene)benzo[1,2-b;3,4-b′]dithiophene-alt-5,5-(4′,7′-di-2-thienyl-5′,6′-dioctyloxy-2′,1′,3′-benzothiadiazole)}(PBDTTDTBT) and poly{4,8-bis(2′-ethyl hexylthiophene)benzo[1,2-b;3,4-b′]dithiophene-alt-5,5-(4′,7′-di-2-thienyl-2-octyl-2′,1′,3′-benzotriazole)} (PBDTTDTBTz), were synthesized by Stille coupling polymerization reactions. All of the polymers were found to be soluble in common organic solvents such as chloroform, tetrahydrofuran and chlorobenzene with excellent film forming properties. Their structures were verified by elemental analysis and NMR spectroscopy, the molecular weights were determined by gel permeation chromatography (GPC) and the thermal properties were investigated by thermogravimetric analysis (TGA). The polymers exhibited tunable absorptions and energy levels on incorporation of different electron accepting units. All the copolymers showed high field hole mobility up to 10−2 order, and their blends with PCBM exhibited mobility as high as 10−1 order by the space-charge-limited current (SCLC) method. Preliminary photovoltaic cells based on the device structure of ITO/PEDOT:PSS/PBDTTDTBO:PC71BM (1:1.5, w/w)/Ca/Al showed a power conversion efficiency of 5.9% with a high open-circuit voltage (Voc) of 0.84 V and a short circuit current density (Jsc) of 11.45 mA cm−2. To the best of our knowledge, this is the highest efficiency for dithienyl benzooxadiazole (DTBO)-based polymer solar cells.
Co-reporter:Jun Yuan, Lu Xiao, Bo Liu, Yongfang Li, Yuehui He, Chunyue Pan and Yingping Zou
Journal of Materials Chemistry A 2013 vol. 1(Issue 36) pp:10639-10645
Publication Date(Web):17 Jun 2013
DOI:10.1039/C3TA11968H
Two new alkoxylphenyl substituted benzo[1,2-b:4,5-b′]dithiophene (BDTPO)-based polymers (PBDTPO-DTBO and PBDTPO-DTBT) were synthesized. Their structures were verified by NMR spectroscopy, the molecular weights were determined by gel permeation chromatography (GPC), and the thermal properties were investigated by thermogravimetric analysis (TGA). UV-Vis absorption spectra of the polymers show broad and strong absorption bands from 300–750 nm both in CHCl3 solutions and films. The resulting copolymers exhibit relatively deep HOMO energy levels (−5.56 and −5.46 eV) and surprisingly high hole mobilities (2.2 × 10−1 and 3.3 × 10−2 cm2 V−1 s−1) for PBDTPO-DTBO and PBDTPO-DTBT, respectively. Preliminary photovoltaic properties of the copolymers blended with [6,6]-phenyl-C71 (or 61)-butyric acid methyl ester (PCBM) as an electron acceptor were investigated. The polymer solar cell (PSC) based on the single layer device structure of ITO/PEDOT:PSS/PBDTPO-DTBO:PC71BM (1:1.5, w/w)/Ca/Al demonstrates a high power conversion efficiency of 6.2% under the illumination of AM 1.5G, 100 mW cm−2.
Co-reporter:Bo Liu, Xuewen Chen, Yuehui He, Lu Xiao, Yongfang Li, Kechao Zhou, Ling Fan and Yingping Zou
RSC Advances 2013 vol. 3(Issue 16) pp:5366-5369
Publication Date(Web):14 Feb 2013
DOI:10.1039/C3RA40268A
A new building block of naphtho[1,2-b:5,6-b′]difuran (NDF) with alkyl chains was firstly designed and synthesized. NDF was used as the electron donor unit in constructing a new low band gap copolymer (PNDFDTBT). A polymer solar cell with the configuration of ITO/PEDOT:PSS/PNDFDTBT:PC71BM (1:2,w/w)/Ca/Al demonstrates a promising power conversion efficiency (PCE) of 4.5%.
Co-reporter:Miao Yang;Xuewen Chen;Yingping Zou;Chunyue Pan;Bo Liu
Journal of Materials Science 2013 Volume 48( Issue 3) pp:1014-1020
Publication Date(Web):2013 February
DOI:10.1007/s10853-012-6831-2
A new linear D–A–D organic small molecule (M1), with triphenylamine as electron donor (D) unit and isoindigo (ID) as electron acceptor (A) unit, was synthesized by Stille coupling reactions. It exhibits broad and strong absorption (300–700 nm), a relatively low HOMO energy level (−5.30 eV), low band gap (1.69 eV), and moderate hole mobility (2.49×10−4 cm2/Vs). Solution-processed small molecule bulk-heterojunction solar cells based on M1: PC61BM (1:3, w/w) blend film exhibits a power conversion efficiency of 0.84 % with an open-circuit voltage (Voc) of 0.78 V, under the illumination of AM1.5, 100 mW/cm2.
Co-reporter:Miao Yang;Xuewen Chen;Yingping Zou;Yuehui He
Journal of Materials Science 2013 Volume 48( Issue 8) pp:3177-3184
Publication Date(Web):2013 April
DOI:10.1007/s10853-012-7096-5
Two new D–A copolymers containing benzotriazole (BTz) acceptor unit and different donor units of benzodithiophene (BDT) and 2,7-carbazole, PBDT-DTBTz and PC-DTBTz, were synthesized for the application as donor materials in polymer solar cells (PSCs). By changing the donor units, the band gaps and the highest occupied molecular orbital (HOMO) energy levels of the copolymers could be finely tuned. PC-DTBTz exhibited the lower HOMO energy level of −5.34 eV, and the lower HOMO energy level can lead to a higher open-circuit voltage (Voc) of 0.73 V in PC-DTBTz-based devices. The PCEs of the PSCs based on PBDT-DTBTz and PC-DTBTz blends with [6,6]-phenyl-C61 butyric acid methyl ester (PC61BM) were 1.55 and 1.33 %, respectively, under the illumination of AM1.5, 100 mW/cm2.
Co-reporter:Xiuping Guo;Lu Xiao;Wanjun Tang;Bo Liu;Ruili Cui
Journal of Materials Science 2013 Volume 48( Issue 17) pp:5833-5839
Publication Date(Web):2013 September
DOI:10.1007/s10853-013-7376-8
A new star-shaped small molecule (M1) with triphenylamine as electron donor (D) unit and 4,7-dithienyl-5,6-bis(n-octyloxy)[2,1,3]benzoselenadiazole as electron acceptor (A) unit was designed and synthesized. The relationship between the structure and properties was well investigated. M1 shows excellent solubility in common organic solvents, broad absorption (300–650 nm), good optical band gap (Eg) (1.96 eV), and proper energy level. Meanwhile, we also investigated the performance of the organic solar cells (OSCs) based on M1 and PC61BM or PC71BM with different weight ratios, under the illumination of AM 1.5G, 100 mW/cm2. The OSCs based on the blend of M1 and PC71BM (1:2, w/w) exhibited the best device performance with a power conversion efficiency of 1.54 %, an open-circuit voltage of 0.91 V, a short-circuit current density of 4.54 mA/cm2, and a fill factor of 37.2 %.
Co-reporter:Xuewen Chen, Bo Liu, Yingping Zou, Lu Xiao, Xiuping Guo, Yuehui He and Yongfang Li
Journal of Materials Chemistry A 2012 vol. 22(Issue 34) pp:17724-17731
Publication Date(Web):13 Jun 2012
DOI:10.1039/C2JM32843G
A new donor–acceptor type copolymer, namely poly{4,8-bis(2-ethylhexyloxy)benzo[1,2-b:3,4-b′]difuran-alt-6-octylnaphtho[2,3-c]thiophene-4,9-dione} (PBDFNTDO) was synthesized by a Stille coupling reaction and characterized by 1H NMR, GPC, TGA, UV-Vis absorption spectroscopy and cyclic voltammetry. PBDFNTDO is readily soluble in common organic solvents with a number-average molecular weight (Mn) of 10.7 kDa mol−1 and a polydispersity index of 1.71. TGA analysis shows the copolymer exhibits good thermal stability with 5% weight loss at a temperature of 341 °C. PBDFNTDO possesses a broad absorption band at 300–750 nm with an optical bandgap of 1.65 eV. Cyclic voltammetry gives HOMO and LUMO energy levels of −5.33 eV and −3.40 eV, respectively. The hole mobility of PBDFNTDO:PC71BM (1:1.5, w/w) reaches up to 5.0 × 10−3 cm2 V−1 s−1 by the space-charge-limited current (SCLC) method. A polymer solar cell with the configuration of ITO/PEDOT:PSS/PBDFNTDO:PC71BM (1:1.5, w/w)/Ca/Al demonstrates a promising power conversion efficiency of 4.71% under the illumination of AM 1.5 G, 100 mW cm−2.
Co-reporter:Xuewen Chen, Bo Liu, Yingping Zou, Wanjun Tang, Yongfang Li and Dequan Xiao
RSC Advances 2012 vol. 2(Issue 19) pp:7439-7448
Publication Date(Web):13 Jun 2012
DOI:10.1039/C2RA20747H
A series of donor–acceptor (D–A) copolymers from a benzodithiophene (BDT) donor unit and a naphtho[2,3-c]thiophene-4,9-dione (NTDO) acceptor unit with different side chains, PBDTNTDO-C1, PBDTNTDO-C2 and PBDTNTDO-C3, were synthesized by a standard Stille cross-coupling polymerization. The thermal, optical and electrochemical properties of the copolymers were well investigated. Preliminary investigations of the copolymers based on the device structure of ITO/PEDOT:PSS/polymer: PC71BM (1:2)/Ca/Al showed power conversion efficiencies (PCEs) of 1.96% for PBDTNTDO-C1, 1.01% for PBDTNTDO-C2 and 2.21% for PBDTNTDO-C3 under the illumination of AM1.5, 100 mW cm−2.
Co-reporter:Ping Ding;Cheng-Che Chu;Yingping Zou;Dequan Xiao;Chunyue Pan;Chain-Shu Hsu
Journal of Applied Polymer Science 2012 Volume 123( Issue 1) pp:99-107
Publication Date(Web):
DOI:10.1002/app.34439
Abstract
To develop conjugated polymers with low bandgap, deep HOMO level, and good solubility, a new conjugated alternating copolymer PC-DODTBT based on N-9′-heptadecanyl-2,7-carbazole and 5, 6-bis(octyloxy)-4,7-di(thiophen-2-yl)benzothiadiazole was synthesized by Suzuki cross-coupling polymerization reaction. The polymer reveals excellent solubility and thermal stability with the decomposition temperature (5% weight loss) of 327°C. The HOMO level of PC-DODTBT is -5.11 eV, indicating that the polymer has relatively deep HOMO level. The hole mobility of PC-DODTBT as deduced from SCLC method was found to be 2.03 × 10−4 cm2/Versus Polymer solar cells (PSCs) based on the blends of PC-DODTBT and [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) with a weight ratio of 1:2.5 were fabricated. Under AM 1.5 (AM, air mass), 100 mW/cm−2 illumination, the devices were found to exhibit an open-circuit voltage (Voc) of 0.73 V, short-circuit current density (Jsc) of 5.63 mA/cm−2, and a power conversion efficiency (PCE) of 1.44%. This photovoltaic performance indicates that the copolymer is promising for polymer solar cells applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Co-reporter:Ping Ding;Yingping Zou;Cheng-Che Chu;Dequan Xiao;Chain-Shu Hsu
Journal of Applied Polymer Science 2012 Volume 125( Issue 5) pp:3936-3945
Publication Date(Web):
DOI:10.1002/app.36541
Abstract
Two conjugated copolymers, poly{4,7-[5,6-bis(octyloxy)]benzo(c)(1,2,5)thiadiazole-alt-4,8-di(2-ethylhexyloxyl)benzo[1,2-b:3,4-b]dithiophene} (P1) and poly(2-{5-[5,6-bis(octyloxy)-4-(thiophen-2-yl)benzo(c)(1,2,5)thiadiazol-7-yl] thiophen-2-yl}-4,8-di(2-ethylhexyloxyl)benzo(1,2-b:3,4-b)dithiophene) (P2), composed of benzodithiophene and 5,6-dioctyloxybenzothiadiazole derivatives with or without thiophene units were synthesized via a Stille cross-coupling polymerization reaction. These copolymers are promising for applications in bulk heterojunction solar cells because of their good solubility, proper thermal stability, moderate hole mobility, and low band gap. The photovoltaic properties of these copolymers were investigated on the basis of blends of the different polymer/(6,6)-phenyl-C71-butyric acid methyl ester (PC71BM) weight ratios under AM1.5G illumination at 100 mW/cm2. The device with indium tin oxide/poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate)/P2:PC71BM (1 : 2 w/w)/Ca/Al gave a relatively better photovoltaic performance with a power conversion efficiency of 1.55%. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Co-reporter:Bo Liu, Ying-ping Zou, Mengqiu Long, Yue-hui He, Hong Zhong, Yong-fang Li
Synthetic Metals 2012 Volume 162(7–8) pp:630-635
Publication Date(Web):May 2012
DOI:10.1016/j.synthmet.2012.02.012
A new solution-processable organic small molecule, namely, TPA–DTBTz–TPA with triphenylamine (TPA) as electron donor and dithienylbenzotriazole (DTBTz) as electron acceptor was synthesized by a Heck cross-coupling reaction, and characterized by 1H NMR, TGA, UV–vis absorption, and cyclic voltammetry. The compound was found to be easily soluble in common organic solvents, such as chloroform, tetrahydrofuran and chlorobenzene with excellent film forming properties. TPA–DTBTz–TPA film exhibits an absorption band from 300 to 620 nm. The organic solar cells based on a blend of TPA–DTBTz–TPA and PC60BM (1:2, w/w) show a power conversion efficiency (PCE) of 0.93% with a short circuit current density of 4.43 mA/cm2 and an open circuit voltage of 0.74 V, under the illumination of AM 1.5, 100 mW/cm2.Graphical abstractHighlights► A solution-processable organic small molecule, TPA–DTBTz–TPA, was synthesized by a Heck cross-coupling reaction and well characterized. ► TPA–DTBTz–TPA film exhibits an absorption band from 300 to 620 nm. ► The organic solar cells based on a blend of TPA–DTBTz–TPA and PC60BM (1:2, w/w) show a power conversion efficiency (PCE) of 0.93%.
Co-reporter:Bo Liu, Xuewen Chen, Yingping Zou, Lu Xiao, Xinjun Xu, Yuehui He, Lidong Li, and Yongfang Li
Macromolecules 2012 Volume 45(Issue 17) pp:6898-6905
Publication Date(Web):August 27, 2012
DOI:10.1021/ma301053q
Three new benzo[1,2-b:4,5-b′]difuran-based donor–acceptor conjugated polymers, namely poly{4,8-bis(2′-ethylhexyloxy)benzo[1,2-b;3,4-b′]difuran-alt-5,5-(4′,7′-di-2-thienyl-5′,6′-dioctyloxy-2′,1′,3′-benzothiadiazole)}(PBDFDODTBT), poly{4,8-bis(2′-ethylhexyloxy)benzo[1,2-b;3,4-b′]difuran-alt-5,5-(4′,7′-di-2-thienyl-2-octyl-2′,1′,3′-benzotriazole)}(PBDFDTBTz), poly{4,8-bis(2′- ethylhexyloxy)benzo[1,2-b;3,4-b′]difuran-alt-5,5-(4′,7′-di-2-thienyl-5′,6′-dioctyloxy-benzo[c][1,2,5]oxadiazole)}(PBDFDTBO), were synthesized by Stille coupling polymerization reactions. All of the polymers were found to be soluble in common organic solvents such as chloroform, tetrahydrofuran and chlorobenzene with excellent film forming properties. Their structures were verified by 1H NMR and elemental analysis, the molecular weights were determined by gel permeation chromatography (GPC) and the thermal properties were investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The polymer films exhibited broad absorption bands. The hole mobility of PBDFDODTBT:PC71BM (1:2, w/w) blend reached up to 6.7 × 10–2 cm2·V–1·s–1 by the space-charge-limited current (SCLC) method. Preliminary photovoltaic cells based on the device structure of ITO/PEDOT:PSS/PBDFDODTBT:PC71BM(1:2, w/w)/Ca/Al showed an open-circuit voltage of 0.69 V, a power conversion efficiency of 4.5% and a short circuit current of 9.87 mA·cm–2.
Co-reporter:Bo Liu;Shanghui Ye;Yingping Zou;Bo Peng;Yuehui He;Kechao Zhou
Macromolecular Chemistry and Physics 2011 Volume 212( Issue 14) pp:1489-1496
Publication Date(Web):
DOI:10.1002/macp.201100080
Co-reporter:Ping Ding ; Chengmei Zhong ; Yingping Zou ; Chunyue Pan ; Hongbin Wu ;Yong Cao
The Journal of Physical Chemistry C 2011 Volume 115(Issue 32) pp:16211-16219
Publication Date(Web):July 12, 2011
DOI:10.1021/jp2031434
Four donor–acceptor (D–A) alternating low bandgap photovoltaic copolymers, using 5,6-bisalkoxylbenzooxadiazole (BX) as an electron-deficient moiety and benzodithiophene or 2,7-carbazole or fluorene as an electron-rich unit, were synthesized and well characterized. The copolymers possess good solubilities, high thermal stabilities, broad absorption, as well as low bandgap ranging from 1.52 to 1.73 eV. Their electronic and photovoltaic properties can be easily tuned by incorporating different donor moieties into the polymer backbone. The HOMO levels of the copolymers were determined by the electron-donating segments, while their LUMO levels were mainly dominated by the BX unit. The preliminary photovoltaic device based on PBDT-DTBX:PC61BM gives a PCE value of 2.9%, which shows that BX probably is a promising electron-accepting building block in organic electronics.
Co-reporter:Dingjun He, Lixia Qiu, Jun Yuan, Zhi-Guo Zhang, Yongfang Li, Yingping Zou
Synthetic Metals (April 2017) Volume 226() pp:
Publication Date(Web):1 April 2017
DOI:10.1016/j.synthmet.2017.01.005
•Two new alkylthio phenyl substituted benzodifuran (BDF)-based polymers-BDFPS-FFQx and BDFPS-HFQx, were synthesized and characterized in detail.•The HOMO energy levels have been fine-tuned by incorporation of alkylthio and F atoms (−5.35 eV for BDFPS-FFQx and −5.31 eV BDFPS-HFQx).•Blending with PC71BM, the device based on BDFPS-FFQx has shown a moderate PCE of 4.62%, the best PCE of 5.16% was obtained for BDFPS-HFQx.In this work, alkylthio group has been used to modify the BDF core as the central building block. Combined with FFQx and HFQx acceptor, two new polymers, named BDFPS-FFQx and BDFPS-HFQx, were designed and characterized in detail. Both polymers exhibit broad absorption in the UV–vis region covered from 300 to 800 nm. The cyclic voltammetry (CV) results suggest that the common effect of alkylthio and fluorine atom could effectively decrease the molecular energy levels. PSCs deliver PCEs of 4.62% and 5.16% for BDFPS-FFQx and BDFPS-HFQx under the illumination of AM1.5, 100 mW cm−2, respectively. Compared with BDFPS-FFQx, the more balanced and higher hole/electron mobility of BDFPS-HFQx greatly contribute to Jsc and FF. Furthermore, the more suitable nanoscale phase separation for exciton dissociation at the polymer and PC71BM interface also plays a vital role in improving photovoltaic performance.Download high-res image (145KB)Download full-size image
Co-reporter:Dingjun He, Lixia Qiu, Jun Yuan, Zhi-Guo Zhang, Yongfang Li, Yingping Zou
Polymer (7 April 2017) Volume 114() pp:348-354
Publication Date(Web):7 April 2017
DOI:10.1016/j.polymer.2017.03.001
Co-reporter:Jun Yuan, Lixia Qiu, Zhiguo Zhang, Yongfang Li, Yuehui He, Lihui Jiang and Yingping Zou
Chemical Communications 2016 - vol. 52(Issue 42) pp:NaN6884-6884
Publication Date(Web):2016/03/18
DOI:10.1039/C6CC01771A
A new tetrafluoridequinoxaline electron accepting block from a quinoxaline core, which is substituted with a fluorine atom onto its backbone and side chains, was designed. A new copolymer (PBDTT-ffQx) was synthesized from tetrafluoridequinoxaline and benzodithiophene. The copolymer was characterized in detail. The photovoltaic properties were well investigated. A high PCE of 8.6% based on the single junction device was obtained.
Co-reporter:Ling Fan, Ruili Cui, Xiuping Guo, Dong Qian, Beibei Qiu, Jun Yuan, Yongfang Li, Wenlong Huang, Junliang Yang, Weifang Liu, Xinjun Xu, Lidong Li and Yingping Zou
Journal of Materials Chemistry A 2014 - vol. 2(Issue 28) pp:NaN5659-5659
Publication Date(Web):2014/05/23
DOI:10.1039/C4TC00738G
A new alkylthienyl substituted thieno[2,3-f]benzofuran (TBF)-based polymer (PTBFTDTBT) was synthesized and characterized. PTBFTDTBT had a high molecular weight, good solubility in common organic solvents, broad visible absorption from 300 to 750 nm, and a relatively deep highest occupied molecular orbital level (−5.2 eV). PTBFTDTBT also showed a field hole mobility up to the order of 10−2 using an organic field effect transistor (OFET) method and an order of 10−2 using a space-charge-limited current (SCLC) method. With the structure of indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):polystyrene sulfonate/PTBFTDTBT:PC71BM (1:2, w/w)/Ca/Al, a power conversion efficiency of 6.42% was obtained with a high short circuit current (Jsc) of 13.51 mA cm−2 and fill factor (FF) of 61%, under the illumination of AM1.5G, at 100 mW cm−2, without any post-treatment. The study demonstrates that TBF is a promising building block for organic electronics.
Co-reporter:Beibei Qiu, Ruili Cui, Jun Yuan, Hongjian Peng, Zhiguo Zhang, Yongfang Li and Yingping Zou
Physical Chemistry Chemical Physics 2015 - vol. 17(Issue 27) pp:NaN17600-17600
Publication Date(Web):2015/05/13
DOI:10.1039/C5CP02127H
Two new alkoxylphenyl substituted thieno[2,3-f]benzofuran (TBFP)-based polymers (PTBFP–BT and PTBFP–BO) were designed and synthesized. Their structures were verified by nuclear magnetic resonance (NMR) spectroscopy, the molecular weights were determined by gel permeation chromatography (GPC) and the thermal properties were investigated by thermogravimetric analysis (TGA). The two polymers showed similar UV-Vis absorption spectra with a broad and strong absorption band from 300–750 nm in solid state. The resulting copolymers exhibited relatively deep highest occupied molecular orbital (HOMO) energy levels (−5.47 and −5.61 eV) for PTBFP–BT and PTBFP–BO, respectively. The device fabricated with PTBFP–BT:PC71BM (1:2) showed better balanced hole and electron mobility of 2.49 × 10−4 cm2 V−1 s−1 and 9.12 × 10−4 cm2 V−1 s−1, respectively, than those of PTBFP–BO based devices. The polymer solar cells (PSCs), based on the single layer device structure of ITO/PEDOT:PSS/PTBFP–BT:PC71BM (1:2, w/w)/ZrAcac/Al with 3 vol% 1,8-diiodooctane (DIO) as additive, showed a relatively high power conversion efficiency (PCE) of 6% under the illumination of AM 1.5G, 100 mW cm−2, with a high fill factor (FF) of 0.69.
Co-reporter:Xuewen Chen, Bo Liu, Yingping Zou, Lu Xiao, Xiuping Guo, Yuehui He and Yongfang Li
Journal of Materials Chemistry A 2012 - vol. 22(Issue 34) pp:NaN17731-17731
Publication Date(Web):2012/06/13
DOI:10.1039/C2JM32843G
A new donor–acceptor type copolymer, namely poly{4,8-bis(2-ethylhexyloxy)benzo[1,2-b:3,4-b′]difuran-alt-6-octylnaphtho[2,3-c]thiophene-4,9-dione} (PBDFNTDO) was synthesized by a Stille coupling reaction and characterized by 1H NMR, GPC, TGA, UV-Vis absorption spectroscopy and cyclic voltammetry. PBDFNTDO is readily soluble in common organic solvents with a number-average molecular weight (Mn) of 10.7 kDa mol−1 and a polydispersity index of 1.71. TGA analysis shows the copolymer exhibits good thermal stability with 5% weight loss at a temperature of 341 °C. PBDFNTDO possesses a broad absorption band at 300–750 nm with an optical bandgap of 1.65 eV. Cyclic voltammetry gives HOMO and LUMO energy levels of −5.33 eV and −3.40 eV, respectively. The hole mobility of PBDFNTDO:PC71BM (1:1.5, w/w) reaches up to 5.0 × 10−3 cm2 V−1 s−1 by the space-charge-limited current (SCLC) method. A polymer solar cell with the configuration of ITO/PEDOT:PSS/PBDFNTDO:PC71BM (1:1.5, w/w)/Ca/Al demonstrates a promising power conversion efficiency of 4.71% under the illumination of AM 1.5 G, 100 mW cm−2.
Co-reporter:Jun Yuan, Lu Xiao, Bo Liu, Yongfang Li, Yuehui He, Chunyue Pan and Yingping Zou
Journal of Materials Chemistry A 2013 - vol. 1(Issue 36) pp:NaN10645-10645
Publication Date(Web):2013/06/17
DOI:10.1039/C3TA11968H
Two new alkoxylphenyl substituted benzo[1,2-b:4,5-b′]dithiophene (BDTPO)-based polymers (PBDTPO-DTBO and PBDTPO-DTBT) were synthesized. Their structures were verified by NMR spectroscopy, the molecular weights were determined by gel permeation chromatography (GPC), and the thermal properties were investigated by thermogravimetric analysis (TGA). UV-Vis absorption spectra of the polymers show broad and strong absorption bands from 300–750 nm both in CHCl3 solutions and films. The resulting copolymers exhibit relatively deep HOMO energy levels (−5.56 and −5.46 eV) and surprisingly high hole mobilities (2.2 × 10−1 and 3.3 × 10−2 cm2 V−1 s−1) for PBDTPO-DTBO and PBDTPO-DTBT, respectively. Preliminary photovoltaic properties of the copolymers blended with [6,6]-phenyl-C71 (or 61)-butyric acid methyl ester (PCBM) as an electron acceptor were investigated. The polymer solar cell (PSC) based on the single layer device structure of ITO/PEDOT:PSS/PBDTPO-DTBO:PC71BM (1:1.5, w/w)/Ca/Al demonstrates a high power conversion efficiency of 6.2% under the illumination of AM 1.5G, 100 mW cm−2.
Co-reporter:Bo Liu, Xuewen Chen, Yuehui He, Yongfang Li, Xinjun Xu, Lu Xiao, Lidong Li and Yingping Zou
Journal of Materials Chemistry A 2013 - vol. 1(Issue 3) pp:NaN577-577
Publication Date(Web):2012/10/16
DOI:10.1039/C2TA00474G
Three new alkylthienyl substituted benzodithiophene (BDT)-based polymers, poly{4,8-bis(2′-ethylhexylthiophene)benzo[1,2-b;3,4-b′]dithiophene-alt-5,5-(4′,7′-di-2-thienyl-5′,6′-dioctyloxy-benzo[c][1,2,5]oxadiazole)}(PBDTTDTBO), poly{4,8-bis(2′-ethylhexylthiophene)benzo[1,2-b;3,4-b′]dithiophene-alt-5,5-(4′,7′-di-2-thienyl-5′,6′-dioctyloxy-2′,1′,3′-benzothiadiazole)}(PBDTTDTBT) and poly{4,8-bis(2′-ethyl hexylthiophene)benzo[1,2-b;3,4-b′]dithiophene-alt-5,5-(4′,7′-di-2-thienyl-2-octyl-2′,1′,3′-benzotriazole)} (PBDTTDTBTz), were synthesized by Stille coupling polymerization reactions. All of the polymers were found to be soluble in common organic solvents such as chloroform, tetrahydrofuran and chlorobenzene with excellent film forming properties. Their structures were verified by elemental analysis and NMR spectroscopy, the molecular weights were determined by gel permeation chromatography (GPC) and the thermal properties were investigated by thermogravimetric analysis (TGA). The polymers exhibited tunable absorptions and energy levels on incorporation of different electron accepting units. All the copolymers showed high field hole mobility up to 10−2 order, and their blends with PCBM exhibited mobility as high as 10−1 order by the space-charge-limited current (SCLC) method. Preliminary photovoltaic cells based on the device structure of ITO/PEDOT:PSS/PBDTTDTBO:PC71BM (1:1.5, w/w)/Ca/Al showed a power conversion efficiency of 5.9% with a high open-circuit voltage (Voc) of 0.84 V and a short circuit current density (Jsc) of 11.45 mA cm−2. To the best of our knowledge, this is the highest efficiency for dithienyl benzooxadiazole (DTBO)-based polymer solar cells.
Co-reporter:Hongjian Peng, Xiangfeng Luan, Liuliu Feng, Jun Yuan, Zhi-Guo Zhang, Yongfang Li and Yingping Zou
Physical Chemistry Chemical Physics 2017 - vol. 19(Issue 22) pp:NaN14295-14295
Publication Date(Web):2017/05/09
DOI:10.1039/C7CP02283B
Ladder-type conjugated structures with rigid and coplanar molecular frameworks feature longer effective conjugation, affirmative optoelectronic properties and strong intermolecular π–π interactions, which are ideal characteristics for organic photovoltaics. Here, a new “zigzag” angular-fused naphthodifuran (zNDF) based on alkoxyphenyl side chains was designed and synthesized. The distannylated zNDF building block was copolymerized with 4,7-di(5-bromothiophen-2-yl)-5,6-dioctyloxybenzo[c][1,2,5]thiadiazole and 5,8-bis(5-bromothiophen-2-yl)-2,3-bis(4-(2-ethylhexyloxy)-3-fluorophenyl)-6,7-difloroquinoxaline (Br-BT and Br-ffQx) acceptor units by Stille cross coupling reaction to form two new medium bandgap donor–acceptor polymers PzNDFP-BT and PzNDFP-ffQx, respectively. The photovoltaic properties of the copolymers blended with [6,6]-phenyl-C71-butyric acid methyl ester (PC71BM) as an electron acceptor were investigated. A 6.9% efficiency was achieved from the single device based on the PzNDFP-BT:PC71BM (1:1.5, w/w) blend film with a 0.25% 1,8-diiodooctane (DIO) additive, which is among the highest efficiency for zNDF-based polymer solar cells.
Co-reporter:Jun Yuan, Jianyong Ouyang, Věra Cimrová, Mario Leclerc, Ahmed Najari and Yingping Zou
Journal of Materials Chemistry A 2017 - vol. 5(Issue 8) pp:NaN1879-1879
Publication Date(Web):2017/01/19
DOI:10.1039/C6TC05381E
Polymer solar cells (PSCs) with a bulk heterojunction (BHJ) structure, i.e. a blend of a p-type conjugated polymer with an n-type semiconductor acceptor, have made rapid progress over the past decade. In comparison with inorganic semiconductor solar cells, PSCs have the advantages of low cost, light weight, solution processability and good mechanical flexibility. In the last few years, various classes of electron-donating polymers have been reported for PSCs. Among them, quinoxaline (Qx) and its derivatives have been widely used as building blocks for optoelectronic applications because they can be easily modified by varying the side chains, such as alkyl chains, conjugated aromatic rings, functional groups, etc. Recently, a power conversion efficiency (PCE) of over 11% was achieved for PSCs with Qx-based polymers. This PCE is among the best for PSCs, and it suggests that Qx-based polymers have great potential for highly efficient PSCs. In this article, we review the recent advances in the design and synthesis of such Qx-based conjugated polymers for photovoltaic applications. Particular attention is paid to the chemical structures of the polymers including flexible chains, conjugated side chains, functional groups, Qx derivatives and the effect of the molecular structure on device performance parameters. We believe that further development of Qx-based polymers will lead to a PCE >12% in the near future.
Co-reporter:Zhenzhen Zhang, Liuliu Feng, Shutao Xu, Jun Yuan, Zhi-Guo Zhang, Hongjian Peng, Yongfang Li and Yingping Zou
Journal of Materials Chemistry A 2017 - vol. 5(Issue 22) pp:NaN11293-11293
Publication Date(Web):2017/05/09
DOI:10.1039/C7TA02486J
A new small molecule, ITTC, bearing an indacenodithieno[3,2-b]thiophene core and a 2-(6-oxo-5,6-dihydro-4H-cyclopenta[c]thiophen-4-ylidene)malononitrile end group, was designed, synthesized and characterized as a non-fullerene electron acceptor. The ITTC possesses strong and broad light absorption, high and balanced charge mobility and a nanoscale interpenetrating morphology when blended with a recently synthesized hexafluoroquinoxaline based polymer donor-HFQx-T. HFQx-T was obtained from a Stille coupling copolymerization of a 2,6-bis(trimethyltin)-4,8-bis(5-(2-ethylhexyl)thiophene-2-yl)benzo[1,2-b:4,5-b′]dithiophene electron donating unit and a hexafluoroquinoxaline based electron accepting unit. The device employing HFQx-T as the donor and ITTC as the acceptor delivered a power conversion efficiency (PCE) of 8.19% without any post-treatment. After thermal annealing, an impressive PCE of 10.4% was obtained. This performance is among the highest PCEs reported for fullerene-free polymer solar cells up to date. This study demonstrates the great potential of ITTC as n-type materials for organic electronics.
![Stannane, 1,1'-[4,8-bis[5-(2-ethylhexyl)-2-thienyl]thieno[2,3-f]benzofuran-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/3782700/1618682-98-6.png)
![Stannane, 1,1'-[4,8-bis[5-(2-ethylhexyl)-2-thienyl]thieno[2,3-f]benzofuran-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/3782700/1618682-98-6_b.png)
![Stannane, 1,1'-[4,8-bis[4-[(2-ethylhexyl)thio]phenyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/3782300/1809534-69-7.png)
![Stannane, 1,1'-[4,8-bis[4-[(2-ethylhexyl)thio]phenyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/3782300/1809534-69-7_b.png)
![Quinoxaline, 5,8-bis(5-bromo-2-thienyl)-2,3-bis[4-[(2-ethylhexyl)oxy]-3-fluorophenyl]-6,7-difluoro-](/data/chemimg/3730600/1902147-01-6.png)
![Quinoxaline, 5,8-bis(5-bromo-2-thienyl)-2,3-bis[4-[(2-ethylhexyl)oxy]-3-fluorophenyl]-6,7-difluoro-](/data/chemimg/3730600/1902147-01-6_b.png)
![Stannane, 1,1'-[4,8-bis[4-[(2-ethylhexyl)oxy]phenyl]thieno[2,3-f]benzofuran-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/3782700/1792967-39-5.png)
![Stannane, 1,1'-[4,8-bis[4-[(2-ethylhexyl)oxy]phenyl]thieno[2,3-f]benzofuran-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/3782700/1792967-39-5_b.png)
![Stannane, 1,1'-[4,8-bis[(2-ethylhexyl)oxy]thieno[2,3-f]benzofuran-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/3782700/1810708-66-7.png)
![Stannane, 1,1'-[4,8-bis[(2-ethylhexyl)oxy]thieno[2,3-f]benzofuran-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/3782700/1810708-66-7_b.png)
![Quinoxaline, 5,8-dibromo-2,3-bis[4-[(2-ethylhexyl)oxy]-3-fluorophenyl]-6,7-difluoro-](/data/chemimg/3730600/1902146-99-9.png)
![Quinoxaline, 5,8-dibromo-2,3-bis[4-[(2-ethylhexyl)oxy]-3-fluorophenyl]-6,7-difluoro-](/data/chemimg/3730600/1902146-99-9_b.png)
![Quinoxaline, 2,3-bis[4-[(2-ethylhexyl)oxy]-3-fluorophenyl]-6,7-difluoro-5,8-di-2-thienyl-](/data/chemimg/3730600/1902147-00-5.png)
![Quinoxaline, 2,3-bis[4-[(2-ethylhexyl)oxy]-3-fluorophenyl]-6,7-difluoro-5,8-di-2-thienyl-](/data/chemimg/3730600/1902147-00-5_b.png)
![Benzo[1,2-b:4,5-b']dithiophene, 4,8-bis[4-[(2-ethylhexyl)thio]phenyl]-](/data/chemimg/3782300/1809534-68-6.png)
![Benzo[1,2-b:4,5-b']dithiophene, 4,8-bis[4-[(2-ethylhexyl)thio]phenyl]-](/data/chemimg/3782300/1809534-68-6_b.png)
![Quinoxaline, 2,3-bis[4-[(2-ethylhexyl)oxy]-3,5-difluorophenyl]-6,7-difluoro-5,8-di-2-thienyl-](/data/chemimg/3782700/2102526-63-4.png)
![Quinoxaline, 2,3-bis[4-[(2-ethylhexyl)oxy]-3,5-difluorophenyl]-6,7-difluoro-5,8-di-2-thienyl-](/data/chemimg/3782700/2102526-63-4_b.png)
![Quinoxaline, 5,8-dibromo-2,3-bis[4-[(2-ethylhexyl)oxy]-3,5-difluorophenyl]-6,7-difluoro-](/data/chemimg/3782700/2102528-46-9.png)
![Quinoxaline, 5,8-dibromo-2,3-bis[4-[(2-ethylhexyl)oxy]-3,5-difluorophenyl]-6,7-difluoro-](/data/chemimg/3782700/2102528-46-9_b.png)
![Quinoxaline, 5,8-bis(5-bromo-2-thienyl)-2,3-bis[4-[(2-ethylhexyl)oxy]-3,5-difluorophenyl]-6,7-difluoro-](/data/chemimg/3782700/2102529-53-1.png)
![Quinoxaline, 5,8-bis(5-bromo-2-thienyl)-2,3-bis[4-[(2-ethylhexyl)oxy]-3,5-difluorophenyl]-6,7-difluoro-](/data/chemimg/3782700/2102529-53-1_b.png)
![Quinoxaline, 5,8-bis(5-bromo-2-thienyl)-2,3-bis[4-[(2-ethylhexyl)oxy]-3-fluorophenyl]-6-fluoro-](/data/chemimg/3782700/2094036-65-2.png)
![Quinoxaline, 5,8-bis(5-bromo-2-thienyl)-2,3-bis[4-[(2-ethylhexyl)oxy]-3-fluorophenyl]-6-fluoro-](/data/chemimg/3782700/2094036-65-2_b.png)
![Pyrido[3,4-b]pyrazine, 5,8-bis(5-bromo-2-thienyl)-2,3-bis[4-[(2-ethylhexyl)oxy]-3-fluorophenyl]-](/data/chemimg/3782700/2103320-72-3.png)
![Pyrido[3,4-b]pyrazine, 5,8-bis(5-bromo-2-thienyl)-2,3-bis[4-[(2-ethylhexyl)oxy]-3-fluorophenyl]-](/data/chemimg/3782700/2103320-72-3_b.png)
![[2,2':5',2''-Terthiophene]-5-carboxaldehyde, 5''-bromo-3,3''-dioctyl-](/data/chemimg/139700/1342311-48-1.png)
![[2,2':5',2''-Terthiophene]-5-carboxaldehyde, 5''-bromo-3,3''-dioctyl-](/data/chemimg/139700/1342311-48-1_b.png)
![4H-Thieno[3,4-c]pyrrole-4,6(5H)-dione, 5-octyl-](/data/chemimg/112100/773881-43-9.png)
![4H-Thieno[3,4-c]pyrrole-4,6(5H)-dione, 5-octyl-](/data/chemimg/112100/773881-43-9_b.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 2,9-bis[3-(dimethylamino)propyl]-](/data/chemimg/134800/117901-97-0.png)
![Anthra[2,1,9-def:6,5,10-d'e'f']diisoquinoline-1,3,8,10(2H,9H)-tetrone, 2,9-bis[3-(dimethylamino)propyl]-](/data/chemimg/134800/117901-97-0_b.png)
![Benzo[1,2-b:4,5-b']difuran](http://img.cochemist.com/ccimg/300/267-58-3.png)
![Benzo[1,2-b:4,5-b']difuran](http://img.cochemist.com/ccimg/300/267-58-3_b.png)
![Thieno[2,3-f]benzofuran](/data/chemimg/3196300/451-42-3.png)
![Thieno[2,3-f]benzofuran](/data/chemimg/3196300/451-42-3_b.png)
![Benzo[1,2-b:4,5-b']dithiophene, 4,8-bis[4-[(2-ethylhexyl)oxy]phenyl]-](/data/chemimg/3782300/1452871-20-3.png)
![Benzo[1,2-b:4,5-b']dithiophene, 4,8-bis[4-[(2-ethylhexyl)oxy]phenyl]-](/data/chemimg/3782300/1452871-20-3_b.png)
![Stannane, 1,1'-[4,8-bis[4-[(2-ethylhexyl)oxy]phenyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/3782400/1452871-15-6.png)
![Stannane, 1,1'-[4,8-bis[4-[(2-ethylhexyl)oxy]phenyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/3782400/1452871-15-6_b.png)
![Stannane, 1,1'-[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/139400/1352642-37-5.png)
![Stannane, 1,1'-[4,8-bis[5-(2-ethylhexyl)-2-thienyl]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/139400/1352642-37-5_b.png)
![1-(4,6-Dibromothieno[3,4-b]thiophen-2-yl)-2-ethylhexan-1-one](http://img.cochemist.com/ccimg/1194700/1194605-76-9.png)
![1-(4,6-Dibromothieno[3,4-b]thiophen-2-yl)-2-ethylhexan-1-one](http://img.cochemist.com/ccimg/1194700/1194605-76-9_b.png)
![2-Thiophenecarboxaldehyde, 5-[4-(diphenylamino)phenyl]-](http://img.cochemist.com/ccimg/291300/291279-14-6.png)
![2-Thiophenecarboxaldehyde, 5-[4-(diphenylamino)phenyl]-](http://img.cochemist.com/ccimg/291300/291279-14-6_b.png)
![Benzenamine, 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N,N-bis[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-](/data/chemimg/102800/267221-90-9.png)
![Benzenamine, 4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-N,N-bis[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)phenyl]-](/data/chemimg/102800/267221-90-9_b.png)
![5,6-Bis(octyloxy)benzo[c][1,2,5]thiadiazole](http://img.cochemist.com/ccimg/1254400/1254353-37-1.png)
![5,6-Bis(octyloxy)benzo[c][1,2,5]thiadiazole](http://img.cochemist.com/ccimg/1254400/1254353-37-1_b.png)
![4,7-Bis(5-bromothiophen-2-yl)-2-octyl-2H-benzo[d][1,2,3]triazole](http://img.cochemist.com/ccimg/1254100/1254062-39-9.png)
![4,7-Bis(5-bromothiophen-2-yl)-2-octyl-2H-benzo[d][1,2,3]triazole](http://img.cochemist.com/ccimg/1254100/1254062-39-9_b.png)
![(4,8-Bis(octyloxy)benzo[1,2-b:4,5-b']dithiophene-2,6-diyl)bis(trimethylstannane)](http://img.cochemist.com/ccimg/1098200/1098102-95-4.png)
![(4,8-Bis(octyloxy)benzo[1,2-b:4,5-b']dithiophene-2,6-diyl)bis(trimethylstannane)](http://img.cochemist.com/ccimg/1098200/1098102-95-4_b.png)
![Stannane, 1,1'-[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']difuran-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/3782700/1352743-87-3.png)
![Stannane, 1,1'-[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']difuran-2,6-diyl]bis[1,1,1-trimethyl-](/data/chemimg/3782700/1352743-87-3_b.png)
![4,7-Dibromo-2-octyl-2H-benzo[d][1,2,3]triazole](http://img.cochemist.com/ccimg/960600/960509-83-5.png)
![4,7-Dibromo-2-octyl-2H-benzo[d][1,2,3]triazole](http://img.cochemist.com/ccimg/960600/960509-83-5_b.png)
![2-Octyl-2H-benzo[d][1,2,3]triazole](http://img.cochemist.com/ccimg/112700/112642-69-0.png)
![2-Octyl-2H-benzo[d][1,2,3]triazole](http://img.cochemist.com/ccimg/112700/112642-69-0_b.png)
