Additives play a crucial role in enhancing the photovoltaic performance of polymer solar cells(PSCs).However,the typical additives used to optimize blend morphology of PSCs are still high boiling-point solvents,while ...Additives play a crucial role in enhancing the photovoltaic performance of polymer solar cells(PSCs).However,the typical additives used to optimize blend morphology of PSCs are still high boiling-point solvents,while their trace residues may reduce device stability.Herein,an effective strategy of“solidification of solvent additive(SSA)”has been developed to convert additive from liquid to solid,by introducing a covalent bond into low-cost solvent diphenyl sulfide(DPS)to synthesize solid dibenzothiophene(DBT)in one-step,which achieves optimized morphology thus promoting efficiency and device stability.Owing to the fine planarity and volatilization of DBT,the DBT-processed films achieve ordered molecular crystallinity and suitable phase separation compared to the additive-free or DPS-treated ones.Importantly,the DBT-processed device also possesses improved light absorption,enhanced charge transport,and thus a champion efficiency of 17.9%is achieved in the PM6:Y6-based PSCs with an excellent additive component tolerance,reproducibility,and stability.Additionally,the DBT-processed PM6:L8-BO-based PSCs are further fabricated to study the universality of SSA strategy,offering an impressive efficiency approaching19%as one of the highest values in binary PSCs.In conclusion,this article developed a promising strategy named SSA to boost efficiency and improve stability of PSCs.展开更多
To achieve high photovoltaic performance of bulk hetero-junction organic solar cells(OSCs), a range of critical factors including absorption profiles, energy level alignment, charge carrier mobility and miscibility of...To achieve high photovoltaic performance of bulk hetero-junction organic solar cells(OSCs), a range of critical factors including absorption profiles, energy level alignment, charge carrier mobility and miscibility of donor and acceptor materials should be carefully considered. For electron-donating materials, the deep highest occupied molecular orbital(HOMO) energy level that is beneficial for high open-circuit voltage is much appreciated. However, a new issue in charge transfer emerges when matching such a donor with an acceptor that has a shallower HOMO energy level. More to this point, the chemical strategies used to enhance the absorption coefficient of acceptors may lead to increased molecular crystallinity, and thus result in less controllable phase-separation of photoactive layer. Therefore, to realize balanced photovoltaic parameters, the donor-acceptor combinations should simultaneously address the absorption spectra, energy levels, and film morphologies. Here, we selected two non-fullerene acceptors, namely BTPT-4F and BTPTT-4F, to match with a wide-bandgap polymer donor P2F-EHp consisting of an imidefunctionalized benzotriazole moiety, as these materials presented complementary absorption and well-matched energy levels. By delicately optimizing the blend film morphology, we demonstrated an unprecedented power conversion efficiency of over 16% for the device based on P2F-EHp:BTPTT-4F, suggesting the great promise of materials matching toward high-performance OSCs.展开更多
With the rapid progress achieved by all-polymer solar cells(all-PSCs), wide-bandgap copolymers have attracted intensive attention for their unique advantage of constructing complementary absorption profiles with conve...With the rapid progress achieved by all-polymer solar cells(all-PSCs), wide-bandgap copolymers have attracted intensive attention for their unique advantage of constructing complementary absorption profiles with conventional narrow-bandgap copolymers. In this work, we designed and synthesized a wide bandgap ternary copolymer PEG-2% which has the benzodithiophene-alt-difluorobenzotriazole as the backbone and the polyethylene glycol(PEG) modified side chain. The PBTA-PEG-2%:N2200 can be processed with a non-chlorinated solvent of 2-methyl-tetrahydrofuran(MeTHF) for the binary all-PSC, which exhibits a moderate photovoltaic performance. In particular, the ternary all-PSCs that consisting an additional narrow bandgap polymer donor PTB7-Th can also be processed with MeTHF, resulting in an unprecedented power conversion efficiency(PCE)of 9.27%, and a high PCE of 8.05% can be achieved with active layer thickness of 240 nm, both of which are the highest values so far reported from all-PSCs. Detailed investigations revealed that the dramatically improved device performances are attributable to the well-extended absorption band in the photoactive layer. Hence,developing novel copolymers with tailored side chains, and introducing additional polymeric components, can broaden the horizon for high-performance all-PSCs.展开更多
A successful transfer of organic photovoltaic technologies from lab to fab has to overcome a range of critical challenges such as developing high-mobility light-harvesting materials,minimizing the upscaling losses,des...A successful transfer of organic photovoltaic technologies from lab to fab has to overcome a range of critical challenges such as developing high-mobility light-harvesting materials,minimizing the upscaling losses,designing advanced solar modules,controlling film quality,decreasing overall cost,and extending long-operation lifetime.To realize large-area devices toward practical applications,much effort has been devoted to understanding the fundamental mechanism of how molecular structures,device architectures,interfacial engineering,and light management and carrier dynamics affect photovoltaic performance.Such studies addressed various fundamental issues of charge carrier behavior in organic heterojunctions primarily in terms of exciton generation dependence upon light incidence,charge transportation dependence on built-in electric field,and charge extraction versus recombination.In consideration of high-throughput roll-to-roll process for large-scale fabrication of organic photovoltaic devices,it is highly appreciable to realize high power conversion efficiencies that are highly tolerable to the film thickness.Herein we summarize the recent progress in developing thick-film organic photovoltaic devices from the perspective of efficiency-loss mechanisms,material design,and device optimization strategies,proposing guidelines for designing high-efficiency thickness-insensitive devices toward mass production.展开更多
基金the financial support from the Scientific Research Project of Education Department of Hunan Province(21C0091)the Open Fund of the State Key Laboratory of Luminescent Materials and Devices(South China University of Technology)(2023skllmd-13)+6 种基金the support from the National Natural Science Foundation of China(22209131,22005121)the open fund support from School of Materials Science and Engineering,Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications(GDRGCS2021002,GDRGCS2022003,GDRGCS2022002)the support from the National Key Research and Development Program of China(2022YFE0132400)the National Natural Science Foundation of China(21875182,52173023)the Key Scientific and Technological Innovation Team Project of Shaanxi Province(2020TD-002)111 Project 2.0(BP0618008)supported by the Director,Office of Science,Office of Basic Energy Sciences,of the U.S.Department of Energy(DE-AC0205CH11231)。
文摘Additives play a crucial role in enhancing the photovoltaic performance of polymer solar cells(PSCs).However,the typical additives used to optimize blend morphology of PSCs are still high boiling-point solvents,while their trace residues may reduce device stability.Herein,an effective strategy of“solidification of solvent additive(SSA)”has been developed to convert additive from liquid to solid,by introducing a covalent bond into low-cost solvent diphenyl sulfide(DPS)to synthesize solid dibenzothiophene(DBT)in one-step,which achieves optimized morphology thus promoting efficiency and device stability.Owing to the fine planarity and volatilization of DBT,the DBT-processed films achieve ordered molecular crystallinity and suitable phase separation compared to the additive-free or DPS-treated ones.Importantly,the DBT-processed device also possesses improved light absorption,enhanced charge transport,and thus a champion efficiency of 17.9%is achieved in the PM6:Y6-based PSCs with an excellent additive component tolerance,reproducibility,and stability.Additionally,the DBT-processed PM6:L8-BO-based PSCs are further fabricated to study the universality of SSA strategy,offering an impressive efficiency approaching19%as one of the highest values in binary PSCs.In conclusion,this article developed a promising strategy named SSA to boost efficiency and improve stability of PSCs.
基金supported by the National Natural Science Foundation of China (91633301, 51521002, 21822505, 21520102006)
文摘To achieve high photovoltaic performance of bulk hetero-junction organic solar cells(OSCs), a range of critical factors including absorption profiles, energy level alignment, charge carrier mobility and miscibility of donor and acceptor materials should be carefully considered. For electron-donating materials, the deep highest occupied molecular orbital(HOMO) energy level that is beneficial for high open-circuit voltage is much appreciated. However, a new issue in charge transfer emerges when matching such a donor with an acceptor that has a shallower HOMO energy level. More to this point, the chemical strategies used to enhance the absorption coefficient of acceptors may lead to increased molecular crystallinity, and thus result in less controllable phase-separation of photoactive layer. Therefore, to realize balanced photovoltaic parameters, the donor-acceptor combinations should simultaneously address the absorption spectra, energy levels, and film morphologies. Here, we selected two non-fullerene acceptors, namely BTPT-4F and BTPTT-4F, to match with a wide-bandgap polymer donor P2F-EHp consisting of an imidefunctionalized benzotriazole moiety, as these materials presented complementary absorption and well-matched energy levels. By delicately optimizing the blend film morphology, we demonstrated an unprecedented power conversion efficiency of over 16% for the device based on P2F-EHp:BTPTT-4F, suggesting the great promise of materials matching toward high-performance OSCs.
基金supported by the National Natural Science Foundation of China(51673069,91633301,51521002,21520102006)Guangdong Natural Science Foundation(2017A030306011)+1 种基金the Pearl River S&T Nova Program of Guangzhou(201710010021)Fundamental Research Funds for the Central Universities
文摘With the rapid progress achieved by all-polymer solar cells(all-PSCs), wide-bandgap copolymers have attracted intensive attention for their unique advantage of constructing complementary absorption profiles with conventional narrow-bandgap copolymers. In this work, we designed and synthesized a wide bandgap ternary copolymer PEG-2% which has the benzodithiophene-alt-difluorobenzotriazole as the backbone and the polyethylene glycol(PEG) modified side chain. The PBTA-PEG-2%:N2200 can be processed with a non-chlorinated solvent of 2-methyl-tetrahydrofuran(MeTHF) for the binary all-PSC, which exhibits a moderate photovoltaic performance. In particular, the ternary all-PSCs that consisting an additional narrow bandgap polymer donor PTB7-Th can also be processed with MeTHF, resulting in an unprecedented power conversion efficiency(PCE)of 9.27%, and a high PCE of 8.05% can be achieved with active layer thickness of 240 nm, both of which are the highest values so far reported from all-PSCs. Detailed investigations revealed that the dramatically improved device performances are attributable to the well-extended absorption band in the photoactive layer. Hence,developing novel copolymers with tailored side chains, and introducing additional polymeric components, can broaden the horizon for high-performance all-PSCs.
基金theNationalKeyResearch and Development ProgramofChina,Grant/Award Number:2019YFA0705901theBasic and AppliedBasicResearch Major Program of Guangdong Province,Grant/Award Number:2019B030302007the Deutsche Forschungsgemeinschaft,Grant/Award Numbers:182849149,SFB 953,INST90/917,INST90/1093-1。
文摘A successful transfer of organic photovoltaic technologies from lab to fab has to overcome a range of critical challenges such as developing high-mobility light-harvesting materials,minimizing the upscaling losses,designing advanced solar modules,controlling film quality,decreasing overall cost,and extending long-operation lifetime.To realize large-area devices toward practical applications,much effort has been devoted to understanding the fundamental mechanism of how molecular structures,device architectures,interfacial engineering,and light management and carrier dynamics affect photovoltaic performance.Such studies addressed various fundamental issues of charge carrier behavior in organic heterojunctions primarily in terms of exciton generation dependence upon light incidence,charge transportation dependence on built-in electric field,and charge extraction versus recombination.In consideration of high-throughput roll-to-roll process for large-scale fabrication of organic photovoltaic devices,it is highly appreciable to realize high power conversion efficiencies that are highly tolerable to the film thickness.Herein we summarize the recent progress in developing thick-film organic photovoltaic devices from the perspective of efficiency-loss mechanisms,material design,and device optimization strategies,proposing guidelines for designing high-efficiency thickness-insensitive devices toward mass production.