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Balanced photoinduced electron transfer (PET) and photoinduced hole transfer (PHT) processes is achieved in ternary OSCs as a result of the improved phase morphology and crystallization of the active layer and the formation of the “acceptor alloys”.
Zewen Chen; Hongzhu Chen; Chuang Feng; Xiaojing Wang; Zhicai He; Yong Cao. The role of balanced dual charge generation pathways in ternary organic solar cells. Journal of Materials Chemistry C 2021, 1 .
AMA StyleZewen Chen, Hongzhu Chen, Chuang Feng, Xiaojing Wang, Zhicai He, Yong Cao. The role of balanced dual charge generation pathways in ternary organic solar cells. Journal of Materials Chemistry C. 2021; ():1.
Chicago/Turabian StyleZewen Chen; Hongzhu Chen; Chuang Feng; Xiaojing Wang; Zhicai He; Yong Cao. 2021. "The role of balanced dual charge generation pathways in ternary organic solar cells." Journal of Materials Chemistry C , no. : 1.
In this article combining density functional theory (DFT) calculations and corresponding experimental measurements, the adsorption behaviors and working mechanism of the alcohol-soluble ionic organic interlayer on different electrode substrates were studied. The results suggest that, when the ionic organic bipyridine salt interlayer (FPyBr) is adsorbed on the Ag surface, Br– will break away from molecule chains and form new chemical bonds with the Ag substrate, as confirmed by both the X-ray photoelectron spectroscopy (XPS) study and DFT study for the first time. Charges are further found to transfer to the Ag substrate from the new interlayer molecular structure without Br–, resulting in adsorption dipoles directed from Ag to the interlayer. Moreover, the direction of the intrinsic dipole of the molecule itself on the Ag substrate is also verified, which is the same as that of the adsorption dipole. Subsequently, the superposition of the two dipoles results in a large reduction of the Ag substrate work function. In addition, the dipole formation mechanism of the interlayer on the ITO surface was also studied. The change in the work function of the ITO substrate by this interlayer is found to be smaller than that of Ag as confirmed by both a DFT study and scanning Kelvin probe microscopy (SKPM) results, which is mainly due to the reversed direction of the molecular intrinsic dipole with respect to the interfacial dipole. The worst device performance of organic solar cells based on the ITO-FPyBr substrate is considered to be one of the consequences of the feature. The findings here are of great importance for the study of the mechanism of the ionic organic interlayer in organic electronic devices, providing insightful understandings on how to further improve the material and device performance.
Chuang Feng; Xiaojing Wang; Guiting Chen; Bin Zhang; Zhicai He; Yong Cao. Mechanism of the Alcohol-Soluble Ionic Organic Interlayer in Organic Solar Cells. Langmuir 2021, 37, 4347 -4354.
AMA StyleChuang Feng, Xiaojing Wang, Guiting Chen, Bin Zhang, Zhicai He, Yong Cao. Mechanism of the Alcohol-Soluble Ionic Organic Interlayer in Organic Solar Cells. Langmuir. 2021; 37 (14):4347-4354.
Chicago/Turabian StyleChuang Feng; Xiaojing Wang; Guiting Chen; Bin Zhang; Zhicai He; Yong Cao. 2021. "Mechanism of the Alcohol-Soluble Ionic Organic Interlayer in Organic Solar Cells." Langmuir 37, no. 14: 4347-4354.
Water‐/alcohol‐soluble polyelectrolyte poly[(9, 9‐bis (3′‐(N,N‐dimethylamino) propyl)‐2, 7‐fluorene)‐alt‐2, 7‐(9, 9‐dioctylfluorene)] (PFN) used in organic solar cells (OSCs) reduces the work function of the electrode due to the effect of an interfacial dipole, which is beneficial for the energy‐level alignment between the electrode and the active layer. To date, the studies on the working mechanism of PFN are mainly conducted through topographical and electronic research. Herein, a dynamic insight into the formation mechanisms of the PFN interlayer at the molecular structural level is established. The charge transfer between PFN and the substrates is verified for the first time by X‐ray photoelectron spectroscopy (XPS) and density functional theory (DFT) studies, which results in chemisorption dipoles with their direction aligned with the intrinsic dipole of the PFN molecule, thereby reducing the work function of the substrate. The larger adsorption energy in the substrates of the nitrogen‐containing side chains of PFN is also identified, which induces the preferential orientation of PFN molecule to reduce the work function of the substrate. By incorporating this interlayer, high efficiency in single‐junction OSCs is achieved using commercial materials. The findings are of great significance for understanding and optimizing the polymer dipole interlayers for OSCs.
Chuang Feng; Xiaojing Wang; Zhicai He; Yong Cao. Formation Mechanism of PFN Dipole Interlayer in Organic Solar Cells. Solar RRL 2021, 5, 2000753 .
AMA StyleChuang Feng, Xiaojing Wang, Zhicai He, Yong Cao. Formation Mechanism of PFN Dipole Interlayer in Organic Solar Cells. Solar RRL. 2021; 5 (4):2000753.
Chicago/Turabian StyleChuang Feng; Xiaojing Wang; Zhicai He; Yong Cao. 2021. "Formation Mechanism of PFN Dipole Interlayer in Organic Solar Cells." Solar RRL 5, no. 4: 2000753.
The novel and appropriate molecular design for polymer donors are playing an important role in realizing high-efficiency and high stable polymer solar cells (PSCs). In this work, four conjugated polymers (PIDT-O, PIDTT-O, PIDT-S and PIDTT-S) with indacenodithiophene (IDT) and indacenodithieno [3,2-b]thiophene (IDTT) as the donor units, and alkoxy-substituted benzoxadiazole and benzothiadiazole derivatives as the acceptor units have been designed and synthesized. Taking advantages of the molecular engineering on polymer backbones, these four polymers showed differently photophysical and photovoltaic properties. They exhibited wide optical bandgaps of 1.88, 1.87, 1.89 and 1.91 eV and quite impressive hole mobilities of 6.01 × 10−4, 7.72 × 10−4, 1.83 × 10−3, and 1.29 × 10−3 cm2 V−1 s−1 for PIDT-O, PIDTT-O, PIDT-S and PIDTT-S, respectively. Through the photovoltaic test via using PIDT-O, PIDTT-O, PIDT-S and PIDTT-S as donor materials and [6,6]-phenyl-C-71-butyric acid methyl ester (PC71BM) as acceptor materials, all the PSCs presented the high open circuit voltages (Vocs) over 0.85 V, whereas the PIDT-S and PIDTT-S based devices showed higher power conversion efficiencies (PCEs) of 5.09% and 4.43%, respectively. Interestingly, the solvent vapor annealing (SVA) treatment on active layers could improve the fill factors (FFs) extensively for these four polymers. For PIDT-S and PIDTT-S, the SVA process improved the FFs exceeding 71%, and ultimately the PCEs were increased to 6.05%, and 6.12%, respectively. Therefore, this kind of wide band-gap polymers are potentially candidates as efficient electron-donating materials for constructing high-performance PSCs.
Siyang Liu; Shuwang Yi; Peiling Qing; Tersilla Virgili; Bin Gu; Zhicai He; Bin Zhang. Molecular Engineering Enhances the Charge Carriers Transport in Wide Band-Gap Polymer Donors Based Polymer Solar Cells. Molecules 2020, 25, 4101 .
AMA StyleSiyang Liu, Shuwang Yi, Peiling Qing, Tersilla Virgili, Bin Gu, Zhicai He, Bin Zhang. Molecular Engineering Enhances the Charge Carriers Transport in Wide Band-Gap Polymer Donors Based Polymer Solar Cells. Molecules. 2020; 25 (18):4101.
Chicago/Turabian StyleSiyang Liu; Shuwang Yi; Peiling Qing; Tersilla Virgili; Bin Gu; Zhicai He; Bin Zhang. 2020. "Molecular Engineering Enhances the Charge Carriers Transport in Wide Band-Gap Polymer Donors Based Polymer Solar Cells." Molecules 25, no. 18: 4101.
Poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) has been is applied as hole transport material in organic electronic devices for more than 20 years. However, the redundant sulfonic acid group of PEDOT:PSS has often been overlooked. Herein, PEDOT:PSS‐DA is prepared via a facile doping of PEDOT:PSS with dopamine hydrochloride (DA·HCl) which reacts with the redundant sulfonic acid of PSS. The PEDOT:PSS‐DA film exhibits enhanced work function and conductivity compared to those of PEDOT:PSS. PEDOT:PSS‐DA‐based devices show a power conversion efficiency of 16.55% which is the highest in organic solar cells (OSCs) with (poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl)‐4‐fluorothiophen‐2‐yl)benzo[1,2‐b:4,5‐b′]dithio‐phene))‐co‐(1,3‐di(5‐thiophene‐2‐yl)‐5,7‐bis(2‐ethylhexyl)‐benzo[1,2‐c:4,5‐c′]dithiophene‐4,8‐dione))] (PM6):(2,2′‐((2Z,2′Z)‐((12,13‐bis(2‐ethylhexyl)‐3,9‐diundecyl‐12,13‐dihydro‐[1,2,5]thiadiazolo[3,4‐e]thieno[2′′,3′:4′,5′]thieno[2′,3′:4,5]pyrrolo[3,2‐g]thieno[2′,3′:4,5]thieno[3,2‐b]indole‐2,10‐diyl)bis(methanylylidene))bis(5,6‐difluoro‐3‐oxo‐2,3‐dihydro‐1H‐indene‐2,1‐diylidene))dimalononitrile) (Y6) as the active layer. Furthermore, PEDOT:PSS‐DA also exhibits enhanced performance in three other donor/acceptor systems, exhibiting high compatibility in OSCs. This work demonstrates that doping PEDOT:PSS with various amino derivatives is a potentially efficient strategy to enhance the performance of PEDOT:PSS in organic electronic devices.
Miao Zeng; Xiaojing Wang; Ruijie Ma; Weiya Zhu; Yuan Li; Zhongxin Chen; Jiawen Zhou; Wenqiang Li; Tao Liu; Zhicai He; He Yan; Fei Huang; Yong Cao. Dopamine Semiquinone Radical Doped PEDOT:PSS: Enhanced Conductivity, Work Function and Performance in Organic Solar Cells. Advanced Energy Materials 2020, 10, 1 .
AMA StyleMiao Zeng, Xiaojing Wang, Ruijie Ma, Weiya Zhu, Yuan Li, Zhongxin Chen, Jiawen Zhou, Wenqiang Li, Tao Liu, Zhicai He, He Yan, Fei Huang, Yong Cao. Dopamine Semiquinone Radical Doped PEDOT:PSS: Enhanced Conductivity, Work Function and Performance in Organic Solar Cells. Advanced Energy Materials. 2020; 10 (25):1.
Chicago/Turabian StyleMiao Zeng; Xiaojing Wang; Ruijie Ma; Weiya Zhu; Yuan Li; Zhongxin Chen; Jiawen Zhou; Wenqiang Li; Tao Liu; Zhicai He; He Yan; Fei Huang; Yong Cao. 2020. "Dopamine Semiquinone Radical Doped PEDOT:PSS: Enhanced Conductivity, Work Function and Performance in Organic Solar Cells." Advanced Energy Materials 10, no. 25: 1.
Green fabrication, including green materials and green solvents, is an attractive technique in organic electronics.
Xiaojing Wang; Shuwang Yi; Zhicai He; Xinhua Ouyang; Hong-Bin Wu; Weiguo Zhu; Bin Zhang; Yong Cao. An environmentally friendly natural polymer as a universal interfacial modifier for fullerene and non-fullerene polymer solar cells. Sustainable Energy & Fuels 2019, 4, 1234 -1241.
AMA StyleXiaojing Wang, Shuwang Yi, Zhicai He, Xinhua Ouyang, Hong-Bin Wu, Weiguo Zhu, Bin Zhang, Yong Cao. An environmentally friendly natural polymer as a universal interfacial modifier for fullerene and non-fullerene polymer solar cells. Sustainable Energy & Fuels. 2019; 4 (3):1234-1241.
Chicago/Turabian StyleXiaojing Wang; Shuwang Yi; Zhicai He; Xinhua Ouyang; Hong-Bin Wu; Weiguo Zhu; Bin Zhang; Yong Cao. 2019. "An environmentally friendly natural polymer as a universal interfacial modifier for fullerene and non-fullerene polymer solar cells." Sustainable Energy & Fuels 4, no. 3: 1234-1241.
The influence of the solution components on the VOC in PTB7-Th: ITIC organic solar cells was studied by several analytical techniques (AFM, GIWAXS, EL), focusing on an inside understanding to the mechanism of the active layer morphology on the VOC.
Xiaojing Wang; Yidong Yang; Zhicai He; HongBin Wu; Yong Cao. Influence of the acceptor crystallinity on the open-circuit voltage in PTB7-Th: ITIC organic solar cells. Journal of Materials Chemistry C 2019, 7, 14861 -14866.
AMA StyleXiaojing Wang, Yidong Yang, Zhicai He, HongBin Wu, Yong Cao. Influence of the acceptor crystallinity on the open-circuit voltage in PTB7-Th: ITIC organic solar cells. Journal of Materials Chemistry C. 2019; 7 (47):14861-14866.
Chicago/Turabian StyleXiaojing Wang; Yidong Yang; Zhicai He; HongBin Wu; Yong Cao. 2019. "Influence of the acceptor crystallinity on the open-circuit voltage in PTB7-Th: ITIC organic solar cells." Journal of Materials Chemistry C 7, no. 47: 14861-14866.
Efficient charge generation is a prerequisite to achieve high power conversion efficiency (PCE) in organic/polymer solar cells (OSCs/PSCs), which involves photo-induced electron transfer and/or hole transfer between donor/acceptor interface upon photoexcitaion. A high yield of charge from both processes usually requires sufficient energy offset between donor and acceptor for charge separation, fast transport and extraction for charge collection, as well as significant absorption complementation for maximizing photons harvest. Here we demonstrate highly efficient PSCs with efficient dual photocurrent generation pathways from a blend of a polymer donor and two narrow bandgap non-fullerene acceptors, with an outstanding certified PCE of 13.0% (verified as 12.5%) in PSCs with single-junction device architecture. The devices from these material systems show non-radiative recombination loss~0.22-0.24 V, one of the smallest values for OSCs achieved so far, and comparable with those of solar cells based on monocrystalline Si or metal-halide perovskites. This study highlights that dual charge generation pathways with high yield and strongly reduced voltage loss are indispensable for further increasing the PCE of OSCs.
Yuan Xie; Wei Huang; Quanbin Liang; Jingshuai Zhu; Zhiyuan Cong; Fengyuan Lin; Shuwang Yi; Guoping Luo; Tingbin Yang; Sha Liu; Zhicai He; Yongye Liang; Xiaowei Zhan; Chao Gao; HongBin Wu; Yong Cao. High-Performance Fullerene-Free Polymer Solar Cells Featuring Efficient Photocurrent Generation from Dual Pathways and Low Nonradiative Recombination Loss. ACS Energy Letters 2018, 4, 8 -16.
AMA StyleYuan Xie, Wei Huang, Quanbin Liang, Jingshuai Zhu, Zhiyuan Cong, Fengyuan Lin, Shuwang Yi, Guoping Luo, Tingbin Yang, Sha Liu, Zhicai He, Yongye Liang, Xiaowei Zhan, Chao Gao, HongBin Wu, Yong Cao. High-Performance Fullerene-Free Polymer Solar Cells Featuring Efficient Photocurrent Generation from Dual Pathways and Low Nonradiative Recombination Loss. ACS Energy Letters. 2018; 4 (1):8-16.
Chicago/Turabian StyleYuan Xie; Wei Huang; Quanbin Liang; Jingshuai Zhu; Zhiyuan Cong; Fengyuan Lin; Shuwang Yi; Guoping Luo; Tingbin Yang; Sha Liu; Zhicai He; Yongye Liang; Xiaowei Zhan; Chao Gao; HongBin Wu; Yong Cao. 2018. "High-Performance Fullerene-Free Polymer Solar Cells Featuring Efficient Photocurrent Generation from Dual Pathways and Low Nonradiative Recombination Loss." ACS Energy Letters 4, no. 1: 8-16.
Quinoxaline (Qx) has an easily modifiable structure, which allows for fine-tuning its properties through optimizing the length of side chains and the kinds of aromatic rings in conjugated side chains.
Shutao Xu; Xiaojing Wang; Liuliu Feng; Zhicai He; Hongjian Peng; Věra Cimrová; Jun Yuan; Zhi-Guo Zhang; Yongfang Li; Yingping Zou. Optimizing the conjugated side chains of quinoxaline based polymers for nonfullerene solar cells with 10.5% efficiency. Journal of Materials Chemistry A 2018, 6, 3074 -3083.
AMA StyleShutao Xu, Xiaojing Wang, Liuliu Feng, Zhicai He, Hongjian Peng, Věra Cimrová, Jun Yuan, Zhi-Guo Zhang, Yongfang Li, Yingping Zou. Optimizing the conjugated side chains of quinoxaline based polymers for nonfullerene solar cells with 10.5% efficiency. Journal of Materials Chemistry A. 2018; 6 (7):3074-3083.
Chicago/Turabian StyleShutao Xu; Xiaojing Wang; Liuliu Feng; Zhicai He; Hongjian Peng; Věra Cimrová; Jun Yuan; Zhi-Guo Zhang; Yongfang Li; Yingping Zou. 2018. "Optimizing the conjugated side chains of quinoxaline based polymers for nonfullerene solar cells with 10.5% efficiency." Journal of Materials Chemistry A 6, no. 7: 3074-3083.
Two large band-gap polymers (PTPACF and PTPA2CF) based on polytriphenylamine derivatives with the introduction of electron-withdrawing trifluoromethyl groups were designed and prepared by Suzuki polycondensation reaction. The chemical structures, thermal, optical and electrochemical properties were characterized in detail. From the UV-visible absorption spectra, the PTPACF and PTPA2CF showed the optical band gaps of 2.01 and 2.07 eV, respectively. The cyclic voltammetry (CV) measurement displayed the deep highest occupied molecular orbital (HOMO) energy levels of −5.33 and −5.38 eV for PTPACF and PTPA2CF, respectively. The hole mobilities, determined by field-effect transistor characterization, were 2.5 × 10−3 and 1.1 × 10−3 cm2 V−1 S−1 for PTPACF and PTPA2CF, respectively. The polymer solar cells (PSCs) were tested under the conventional device structure of ITO/PEDOT:PSS/polymer:PC71BM/PFN/Al. All of the PSCs showed the high open circuit voltages (Vocs) with the values approaching 1 V. The PTPACF and PTPA2CF based PSCs gave the power conversion efficiencies (PCEs) of 3.24% and 2.40%, respectively. Hence, it is a reliable methodology to develop high-performance large band-gap polymer donors with high Vocs through the feasible side-chain modification.
Shuwang Yi; Wanyuan Deng; Sheng Sun; Linfeng Lan; Zhicai He; Wei Yang; Bin Zhang. Trifluoromethyl-Substituted Large Band-Gap Polytriphenylamines for Polymer Solar Cells with High Open-Circuit Voltages. Polymers 2018, 10, 52 .
AMA StyleShuwang Yi, Wanyuan Deng, Sheng Sun, Linfeng Lan, Zhicai He, Wei Yang, Bin Zhang. Trifluoromethyl-Substituted Large Band-Gap Polytriphenylamines for Polymer Solar Cells with High Open-Circuit Voltages. Polymers. 2018; 10 (1):52.
Chicago/Turabian StyleShuwang Yi; Wanyuan Deng; Sheng Sun; Linfeng Lan; Zhicai He; Wei Yang; Bin Zhang. 2018. "Trifluoromethyl-Substituted Large Band-Gap Polytriphenylamines for Polymer Solar Cells with High Open-Circuit Voltages." Polymers 10, no. 1: 52.
A class of novel alcohol-soluble polyfluorene derivatives with a pyridine group incorporating at the side chains of fluorene is developed to modify the cathode interfaces of both conventional and inverted polymer solar cells. A class of novel alcohol-soluble conjugated polymers with pyridine incorporated at the side chains of fluorene scaffolds is developed and used as cathode interfacial layers (CILs) for both conventional and inverted polymer solar cells (PSCs). The pyridine group can endow these polymers with solubility in methanol (MeOH) in the presence of trace acetic acid (AcOH), which is beneficial for the realization of PSC fabrication by low-cost solution processing without interfacial mixing. In addition, the pyridine group can not only build interfacial dipoles at the CIL/cathode interfaces, leading to reduced cathode work functions and improved open-circuit voltages, but also n-dope the fullerene acceptors, which decreases the interfacial energy loss at the cathode side. As a result, for conventional PSCs based on poly[ N -9′′-heptadecanyl-2,7-carbazole- alt -5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT):[6,6]-phenyl C71-butyric acid methyl ester (PC71BM), these resulting polymers can increase the power conversion efficiency (PCE) from 5.38% (without any CIL) and 5.50% (with MeOH/AcOH treatment) to 6.54%–6.97%. For the inverted PSCs based on poly[4,8-bis(2-ethylhexyloxyl)benzo[1,2- b :4,5- b ′]dithiophene-2,6-diyl- alt -ethylhexyl-3-fluorothieno[3,4- b ]thiophene-2-carboxylate-4,6-diyl] (PTB7):PC71BM, these resulting polymers can improve the PCE from 3.64% (without any CIL) and 4.25% (with MeOH/AcOH treatment) to 7.21%–7.96%. Therefore, these pyridine-functionalized polymers are promising candidates as CILs for high-performance PSCs.
Guiting Chen; Sha Liu; Zhicai He; Hong-Bin Wu; Wei Yang; Bin Zhang; Yong Cao. Pyridine-incorporated alcohol-soluble neutral polyfluorene derivatives as efficient cathode-modifying layers for polymer solar cells. Polymer Chemistry 2017, 8, 6720 -6732.
AMA StyleGuiting Chen, Sha Liu, Zhicai He, Hong-Bin Wu, Wei Yang, Bin Zhang, Yong Cao. Pyridine-incorporated alcohol-soluble neutral polyfluorene derivatives as efficient cathode-modifying layers for polymer solar cells. Polymer Chemistry. 2017; 8 (44):6720-6732.
Chicago/Turabian StyleGuiting Chen; Sha Liu; Zhicai He; Hong-Bin Wu; Wei Yang; Bin Zhang; Yong Cao. 2017. "Pyridine-incorporated alcohol-soluble neutral polyfluorene derivatives as efficient cathode-modifying layers for polymer solar cells." Polymer Chemistry 8, no. 44: 6720-6732.
In recent years, cathode interfacial layers (CILs), as versatile functional layers, have been investigated extensively for their use in organic electronics. Many excellent CILs have been designed and prepared, and these have provided a distinct improvement in device performance. In this work, two bathophenanthroline-based cationic CILs (Bphen-Et and Bphen-Pr) for use in polymer solar cells (PSCs) were synthesized by a simple intramolecular cyclization reaction with 1,2-dibromoethane and 1,3-dibromopropane, respectively. The chemical, thermal, photophysical, electrochemical and photovoltaic properties were characterized. Bphen-Et and Bphen-Pr exhibited a high thermal stability, and their glass transition temperatures exceeded 100°C. Bphen-Et had a glass transition temperature above 181°C. The electrochemical characterization showed that Bphen-Et and Bphen-Pr had very deep highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels, where the HOMOs and LUMOs for Bphen-Et and Bphen-Pr were -6.63 and -6.67 and -4.16 and -4.18 eV, respectively. These very low HOMOs and LUMOs enhanced the photovoltaic performance and decreased the interfacial energy loss. PSCs based on the poly[4,8-bis(2-ethylhexyloxyl)benzo[1,2-b:4,5-b′]dithio-phene-2,6-diyl-alt-ethylhexyl-3-fluorothithieno[3,4-b]thiophene-2-carboxylate-4,6-diyl] (PTB7): [6,6]-phenyl-C71 butyric acid methyl ester (PC71BM) system with Bphen-Et and Bphen-Pr CILs exhibited a simultaneous enhancement in open-circuit voltage, short-circuit current density and fill factor, whereas the power conversion efficiency increased from 3.98% to 8.05%, relative to the bare Al device. This kind of cationic aromatic compound shows promise as a candidate CIL for use in PSCs.
Bin Zhang; Shuwang Yi; Guiting Chen; Zhicai He; Hong-Bin Wu; Wei Yang; Fangfang Niu; Junle Qu; Pengju Zeng; Yong Cao. Water- and alcohol-soluble cationic phenanthroline derivatives as efficient cathode interfacial layers for bulk-heterojunction polymer solar cells. Journal of Materials Chemistry C 2017, 5, 4858 -4866.
AMA StyleBin Zhang, Shuwang Yi, Guiting Chen, Zhicai He, Hong-Bin Wu, Wei Yang, Fangfang Niu, Junle Qu, Pengju Zeng, Yong Cao. Water- and alcohol-soluble cationic phenanthroline derivatives as efficient cathode interfacial layers for bulk-heterojunction polymer solar cells. Journal of Materials Chemistry C. 2017; 5 (20):4858-4866.
Chicago/Turabian StyleBin Zhang; Shuwang Yi; Guiting Chen; Zhicai He; Hong-Bin Wu; Wei Yang; Fangfang Niu; Junle Qu; Pengju Zeng; Yong Cao. 2017. "Water- and alcohol-soluble cationic phenanthroline derivatives as efficient cathode interfacial layers for bulk-heterojunction polymer solar cells." Journal of Materials Chemistry C 5, no. 20: 4858-4866.
A novel n-type conjugated polymer containing dibenzothiophene-S,S-dioxide (FSO), bispyridinium, and fluorene scaffolds in the backbone (PFSOPyCl) was synthesized and used in the cathode interfacial layers (CILs) of conventional polymer solar cells (PSCs). The high electron affinities and large planar structures of the FSO and bispyridinium units endowed this polymer with good energy level alignments with [6,6]-phenyl-C71 butyric acid methyl ester (PC71BM) and metal cathode, and excellent electron transport and extraction properties. Polymer solar cells (PSCs) based on the poly[N-9″-heptadecanyl-2,7-carbazole-alt-5,5-(4′,7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT):PC71BM system with PFSOPyCl CIL exhibited simultaneous enhancement in open-circuit voltage (Voc), short-circuit current density (Jsc), and fill factor (FF), while the power conversion efficiency increased from 5.47% to 6.79%, relative to the bare Al device. Besides, PSC based on the poly[4,8-bis(2-ethylhexyloxyl)benzo[1,2-b:4,5-b′]dithio-phene-2,6-diyl-alt-ethylhexyl-3-fluorothithieno [3,4-b]thiophene-2-carboxylate-4,6-diyl] (PTB7):PC71BM system achieved a PCE of 8.43% when using PFSOPyCl as CIL. Hence, PFSOPyCl is a promising candidate CIL for PSCs.
Guiting Chen; Sha Liu; Jin Xu; Ruifeng He; Zhicai He; Hong-Bin Wu; Wei Yang; Bin Zhang; Yong Cao. Dibenzothiophene-S,S-dioxide and Bispyridinium-Based Cationic Polyfluorene Derivative as an Efficient Cathode Modifier for Polymer Solar Cells. ACS Applied Materials & Interfaces 2017, 9, 4778 -4787.
AMA StyleGuiting Chen, Sha Liu, Jin Xu, Ruifeng He, Zhicai He, Hong-Bin Wu, Wei Yang, Bin Zhang, Yong Cao. Dibenzothiophene-S,S-dioxide and Bispyridinium-Based Cationic Polyfluorene Derivative as an Efficient Cathode Modifier for Polymer Solar Cells. ACS Applied Materials & Interfaces. 2017; 9 (5):4778-4787.
Chicago/Turabian StyleGuiting Chen; Sha Liu; Jin Xu; Ruifeng He; Zhicai He; Hong-Bin Wu; Wei Yang; Bin Zhang; Yong Cao. 2017. "Dibenzothiophene-S,S-dioxide and Bispyridinium-Based Cationic Polyfluorene Derivative as an Efficient Cathode Modifier for Polymer Solar Cells." ACS Applied Materials & Interfaces 9, no. 5: 4778-4787.
Organic photovoltaic (OPV) devices, which can directly convert absorbed sunlight to electricity, are stacked thin films of tens to hundreds of nanometers. They have emerged as a promising candidate for affordable, clean, and renewable energy. In the past few years, a rapid increase has been seen in the power conversion efficiency of OPV devices toward 10% and above, through comprehensive optimizations via novel photoactive donor and acceptor materials, control of thin-film morphology on the nanoscale, device structure developments, and interfacial and optical engineering. The intrinsic problems of short exciton diffusion length and low carrier mobility in organic semiconductors creates a challenge for OPV designs for achieving optically thick and electrically thin device structures to achieve sufficient light absorption and efficient electron/hole extraction. Recent advances in the field of OPV devices are reviewed, with a focus on the progress in device architecture and optical engineering approaches that lead to improved electrical and optical characteristics in OPV devices. Successful strategies are highlighted for light wave distribution, modulation, and absorption promotion inside the active layer of OPV devices by incorporating periodic nanopatterns/nanostructures or incorporating metallic nanomaterials and nanostructures.
Guoping Luo; Xingang Ren; Su Zhang; HongBin Wu; Wallace C. H. Choy; Zhicai He; Yong Cao. Recent Advances in Organic Photovoltaics: Device Structure and Optical Engineering Optimization on the Nanoscale. Small 2016, 12, 1547 -1571.
AMA StyleGuoping Luo, Xingang Ren, Su Zhang, HongBin Wu, Wallace C. H. Choy, Zhicai He, Yong Cao. Recent Advances in Organic Photovoltaics: Device Structure and Optical Engineering Optimization on the Nanoscale. Small. 2016; 12 (12):1547-1571.
Chicago/Turabian StyleGuoping Luo; Xingang Ren; Su Zhang; HongBin Wu; Wallace C. H. Choy; Zhicai He; Yong Cao. 2016. "Recent Advances in Organic Photovoltaics: Device Structure and Optical Engineering Optimization on the Nanoscale." Small 12, no. 12: 1547-1571.
The inverted-structured PSC based onPBDTT-S-TT-CFexhibited a high PCE of 9.58% with a remarkably highVocof 0.89 V.
Chaohua Cui; Zhicai He; Yue Wu; Xiao Cheng; HongBin Wu; Yongfang Li; Yong Cao; Wai-Yeung Wong. High-performance polymer solar cells based on a 2D-conjugated polymer with an alkylthio side-chain. Energy & Environmental Science 2016, 9, 885 -891.
AMA StyleChaohua Cui, Zhicai He, Yue Wu, Xiao Cheng, HongBin Wu, Yongfang Li, Yong Cao, Wai-Yeung Wong. High-performance polymer solar cells based on a 2D-conjugated polymer with an alkylthio side-chain. Energy & Environmental Science. 2016; 9 (3):885-891.
Chicago/Turabian StyleChaohua Cui; Zhicai He; Yue Wu; Xiao Cheng; HongBin Wu; Yongfang Li; Yong Cao; Wai-Yeung Wong. 2016. "High-performance polymer solar cells based on a 2D-conjugated polymer with an alkylthio side-chain." Energy & Environmental Science 9, no. 3: 885-891.
Aggregation behaviour and –OH content of lignosulfonate play a key role for the promising performance when PEDOT:LS acts as the HEL in PSCs.
Nanlong Hong; Xueqing Qiu; Wanyuan Deng; Zhicai He; Yuan Li. Effect of aggregation behavior and phenolic hydroxyl group content on the performance of lignosulfonate doped PEDOT as a hole extraction layer in polymer solar cells. RSC Advances 2015, 5, 90913 -90921.
AMA StyleNanlong Hong, Xueqing Qiu, Wanyuan Deng, Zhicai He, Yuan Li. Effect of aggregation behavior and phenolic hydroxyl group content on the performance of lignosulfonate doped PEDOT as a hole extraction layer in polymer solar cells. RSC Advances. 2015; 5 (110):90913-90921.
Chicago/Turabian StyleNanlong Hong; Xueqing Qiu; Wanyuan Deng; Zhicai He; Yuan Li. 2015. "Effect of aggregation behavior and phenolic hydroxyl group content on the performance of lignosulfonate doped PEDOT as a hole extraction layer in polymer solar cells." RSC Advances 5, no. 110: 90913-90921.
We demonstrate spin coating together with solvent annealing, which can be used to tune the morphology of the BHJ active layer and thus enhance device performances.
Zhicai He; Feng Liu; Cheng Wang; Jihua Chen; Lilin He; Dennis Nordlund; HongBin Wu; Thomas P. Russell; Yong Cao. Simultaneous spin-coating and solvent annealing: manipulating the active layer morphology to a power conversion efficiency of 9.6% in polymer solar cells. Materials Horizons 2015, 2, 592 -597.
AMA StyleZhicai He, Feng Liu, Cheng Wang, Jihua Chen, Lilin He, Dennis Nordlund, HongBin Wu, Thomas P. Russell, Yong Cao. Simultaneous spin-coating and solvent annealing: manipulating the active layer morphology to a power conversion efficiency of 9.6% in polymer solar cells. Materials Horizons. 2015; 2 (6):592-597.
Chicago/Turabian StyleZhicai He; Feng Liu; Cheng Wang; Jihua Chen; Lilin He; Dennis Nordlund; HongBin Wu; Thomas P. Russell; Yong Cao. 2015. "Simultaneous spin-coating and solvent annealing: manipulating the active layer morphology to a power conversion efficiency of 9.6% in polymer solar cells." Materials Horizons 2, no. 6: 592-597.
The maximum open-circuit voltage of a solar cell can be evaluated in terms of its ability to emit light. We herein verify the reciprocity relation between the electroluminescence spectrum and subband-gap quantum efficiency spectrum for several photovoltaic technologies at different stages of commercial development, including inorganic, organic, and a type of methyl-ammonium lead- halide CH3NH3PbI3−xClx perovskite solar cells. Based on the detailed balance theory and reciprocity relations between light emission and light absorption, voltage losses at open circuit are quantified and assigned to specific mechanisms, namely, absorption edge broadening and nonradiative recombination. The voltage loss due to nonradiative recombination is low for inorganic solar cells (0.04–0.21 V), while for organic solar cell devices it is larger but surprisingly uniform, with values of 0.34–0.44 V for a range of material combinations. We show that, in CH3NH3PbI3−xClx perovskite solar cells that exhibit hysteresis, the loss to nonradiative recombination varies substantially with voltage scan conditions. We then show that for different solar cell technologies there is a roughly linear relation between the power conversion efficiency and the voltage loss due to nonradiative recombination.
Jizhong Yao; Thomas Kirchartz; Michelle Vezie; Mark A. Faist; Wei Gong; Zhicai He; HongBin Wu; Joel Troughton; Trystan Watson; Daniel Bryant; Jenny Nelson. Quantifying Losses in Open-Circuit Voltage in Solution-Processable Solar Cells. Physical Review Applied 2015, 4, 014020 .
AMA StyleJizhong Yao, Thomas Kirchartz, Michelle Vezie, Mark A. Faist, Wei Gong, Zhicai He, HongBin Wu, Joel Troughton, Trystan Watson, Daniel Bryant, Jenny Nelson. Quantifying Losses in Open-Circuit Voltage in Solution-Processable Solar Cells. Physical Review Applied. 2015; 4 (1):014020.
Chicago/Turabian StyleJizhong Yao; Thomas Kirchartz; Michelle Vezie; Mark A. Faist; Wei Gong; Zhicai He; HongBin Wu; Joel Troughton; Trystan Watson; Daniel Bryant; Jenny Nelson. 2015. "Quantifying Losses in Open-Circuit Voltage in Solution-Processable Solar Cells." Physical Review Applied 4, no. 1: 014020.
The realization of high-efficiency organic small molecule: Fullerene solar cells are challenging but become more and more feasible due to the rapid development in donor materials and device fabrication techniques. In the past several years, the optimization in the processing techniques, such as, solvent vapor annealing (SVA), the use of solvent additives had led to superior improvement in the device performance of organic solar cells from different donor systems, but at an expense of reduction in the open-circuit voltage (VOC). In this paper, we report that the overall device performance of the organic small molecule solar cells (SMSCs) can be significantly enhanced through a two-step process consisting of SVA and thermal annealing (TA) (short for SVA+TA), especially the reduction in VOC can be effectively avoided in case of exclusive use of SVA. The carrier dynamics is determined by transient photovoltage and transient photocurrent measurements, which can provide information on the origin of enhanced device performance upon the two-step annealing. The observed VOC recovery is attributed to the preferable change in charge dynamic, thus, leading to a superior overall device performance. Furthermore, the SVA and the consequential TA are complementary to each other; thus, the two-step annealing method represents a feasible route to simultaneously improve the VOC, JSC, FF, and PCE of SMSCs.
Hui Chen; Jingsheng Miao; Jun Yan; Zhicai He; HongBin Wu. Improving Organic Solar Cells Efficiency Through a Two-Step Method Consisting of Solvent Vapor Annealing and Thermal Annealing. IEEE Journal of Selected Topics in Quantum Electronics 2015, 22, 66 -72.
AMA StyleHui Chen, Jingsheng Miao, Jun Yan, Zhicai He, HongBin Wu. Improving Organic Solar Cells Efficiency Through a Two-Step Method Consisting of Solvent Vapor Annealing and Thermal Annealing. IEEE Journal of Selected Topics in Quantum Electronics. 2015; 22 (1):66-72.
Chicago/Turabian StyleHui Chen; Jingsheng Miao; Jun Yan; Zhicai He; HongBin Wu. 2015. "Improving Organic Solar Cells Efficiency Through a Two-Step Method Consisting of Solvent Vapor Annealing and Thermal Annealing." IEEE Journal of Selected Topics in Quantum Electronics 22, no. 1: 66-72.
Jingsheng Miao; Hui Chen; Feng Liu; Baofeng Zhao; Lingyu Hu; Zhicai He; HongBin Wu. Efficiency enhancement in solution-processed organic small molecule: Fullerene solar cells via solvent vapor annealing. Applied Physics Letters 2015, 106, 183302 .
AMA StyleJingsheng Miao, Hui Chen, Feng Liu, Baofeng Zhao, Lingyu Hu, Zhicai He, HongBin Wu. Efficiency enhancement in solution-processed organic small molecule: Fullerene solar cells via solvent vapor annealing. Applied Physics Letters. 2015; 106 (18):183302.
Chicago/Turabian StyleJingsheng Miao; Hui Chen; Feng Liu; Baofeng Zhao; Lingyu Hu; Zhicai He; HongBin Wu. 2015. "Efficiency enhancement in solution-processed organic small molecule: Fullerene solar cells via solvent vapor annealing." Applied Physics Letters 106, no. 18: 183302.