In the field of organic solar cells(OSCs),side-chain engineering is a key strategy for developing high-performance non-fullerene small molecule acceptors(SMAs),which could adjust the material solubility and modulate t...In the field of organic solar cells(OSCs),side-chain engineering is a key strategy for developing high-performance non-fullerene small molecule acceptors(SMAs),which could adjust the material solubility and modulate the intermolecular stacking properties,profoundly impacting the film morphology and thus acting on the final power conversion efficiency(PCE) of the materials.In this study,two asymmetric acceptor molecules,Qx-Ph Br-BO and Qx-Ph Br-X,were synthesized by migrating the branching site of the outer side chain from the β-site to the γ-site.The branching site located at the γ-site could reduce the steric-hindrance effect and enhance the molecular aggregation behavior,giving rise to redshifted absorption and tight π-π stacking.Morphology analysis shows that the Qx-Ph Br-X-based devices have smoother surfaces and a phase-separated structure,which is more favorable for charge transport and extraction.The Qx-Ph Br-X-based devices exhibit balanced hole-electron mobility,efficient exciton dissociation,and low charge recombination.As a result,Qx-Ph Br-X with γ-site branching exhibits superior photovoltaic performance with a PCE of 17.16 %,which is significantly higher than that of Qx-Ph Br-BO at 16.28 %.These results highlight the importance of side-chain modifications for optimizing OSC efficiency and provide an important reference for precise tuning of side-chain structures in future molecular design.展开更多
A nonfused ring electron acceptor(NFREA),designated as TT-Ph-C6,has been synthesized with the aim of enhancing the power conversion efficiency(PCE)of organic solar cells(OSCs).By integrating asymmetric phenylalkylamin...A nonfused ring electron acceptor(NFREA),designated as TT-Ph-C6,has been synthesized with the aim of enhancing the power conversion efficiency(PCE)of organic solar cells(OSCs).By integrating asymmetric phenylalkylamino side groups,TT-Ph-C6 demonstrates excellent solubility and its crystal structure exhibits compact packing structures with a three-dimensional molecular stacking network.These structural attributes markedly promote exciton diffusion and charge carrier mobility,particularly advantageous for the fabrication of thick-film devices.TT-Ph-C6-based devices have attained a PCE of 18.01%at a film thickness of 100 nm,and even at a film thickness of 300 nm,the PCE remains at 14.64%,surpassing that of devices based on 2BTh-2F.These remarkable properties position TT-Ph-C6 as a highly promising NFREA material for boosting the efficiency of OSCs.展开更多
The fluorination strategy has been proven effective in significantly enhancing the photovoltaic performance of organic solar cells(OSCs) based on non-fused ring electron acceptors(NFREAs).However,research on the impac...The fluorination strategy has been proven effective in significantly enhancing the photovoltaic performance of organic solar cells(OSCs) based on non-fused ring electron acceptors(NFREAs).However,research on the impact of fluorination positions at side chains on NFREAs device performance remains scant.In this study,we introduce two isomeric NFREAs,designated as GA-2F-E and GA-2F,distinguished by their fluorination positions at the side chains.Both NFREAs share a thiophene[3,2-b]thiophene core,but their side chains differ:GA-2F-E features two(4-butylphenyl)-N-(4-fluorophenyl) amino groups,whereas GA-2F's side chains consist of bis(4-fluorophenyl)amino and bis(4-butylphenyl)amino groups attached to opposite sides of the core.To delve into the influence of fluorination positions on the optoelectronic properties,aggregation behavior,and overall efficiency of the acceptor molecules,a comprehensive investigation was conducted.The findings reveal that,despite similar photophysical properties and comparable absorption bandwidths,GA-2F-E,with fluorine atoms positioned on both sides of the molecular framework,demonstrates more compact π-π stacking,reduced bimolecular recombination,superior exciton transport,and a more balanced,higher mobility.As a result of these advantages,OSCs optimized with D18:GA-2F-E achieve a remarkable power conversion efficiency(PCE) of 16.45 %,surpassing the 15.83 %PCE of devices utilizing D18:GA-2F.This research underscores the potential of NFREAs in future applications and highlights the significance of fluorination positions in enhancing OSC performance,paving the way for the development of more efficient NFREAs.展开更多
基金the financial support by the Beijing Natural Science Foundation (No.Z230018)the Strategic Priority Research Program of the Chinese Academy of Sciences (No.XDB0520102)CAS Project for Young Scientists in Basic Research (No.YSBR-102)。
文摘In the field of organic solar cells(OSCs),side-chain engineering is a key strategy for developing high-performance non-fullerene small molecule acceptors(SMAs),which could adjust the material solubility and modulate the intermolecular stacking properties,profoundly impacting the film morphology and thus acting on the final power conversion efficiency(PCE) of the materials.In this study,two asymmetric acceptor molecules,Qx-Ph Br-BO and Qx-Ph Br-X,were synthesized by migrating the branching site of the outer side chain from the β-site to the γ-site.The branching site located at the γ-site could reduce the steric-hindrance effect and enhance the molecular aggregation behavior,giving rise to redshifted absorption and tight π-π stacking.Morphology analysis shows that the Qx-Ph Br-X-based devices have smoother surfaces and a phase-separated structure,which is more favorable for charge transport and extraction.The Qx-Ph Br-X-based devices exhibit balanced hole-electron mobility,efficient exciton dissociation,and low charge recombination.As a result,Qx-Ph Br-X with γ-site branching exhibits superior photovoltaic performance with a PCE of 17.16 %,which is significantly higher than that of Qx-Ph Br-BO at 16.28 %.These results highlight the importance of side-chain modifications for optimizing OSC efficiency and provide an important reference for precise tuning of side-chain structures in future molecular design.
基金Financial support from the National Natural Science Foundation of China(22375024,21975031,21734009,51933001,22109080,and 52173174)the Natural Science Foundation of Shandong Province(No.ZR2022YQ45)+2 种基金the Taishan Scholars Program(Nos.tstp20221121 and tsqnz20221134)The Beijing Natural Science Foundation(No.2244073)supported by State Key Laboratory of Bio-Fibers and Eco-Textiles(Qingdao University)(RZ2200002821)is acknowledged.
文摘A nonfused ring electron acceptor(NFREA),designated as TT-Ph-C6,has been synthesized with the aim of enhancing the power conversion efficiency(PCE)of organic solar cells(OSCs).By integrating asymmetric phenylalkylamino side groups,TT-Ph-C6 demonstrates excellent solubility and its crystal structure exhibits compact packing structures with a three-dimensional molecular stacking network.These structural attributes markedly promote exciton diffusion and charge carrier mobility,particularly advantageous for the fabrication of thick-film devices.TT-Ph-C6-based devices have attained a PCE of 18.01%at a film thickness of 100 nm,and even at a film thickness of 300 nm,the PCE remains at 14.64%,surpassing that of devices based on 2BTh-2F.These remarkable properties position TT-Ph-C6 as a highly promising NFREA material for boosting the efficiency of OSCs.
基金financially supported by the National Natural Science Foundation of China (Nos.22375024,21975031,51933001,and 21734009)。
文摘The fluorination strategy has been proven effective in significantly enhancing the photovoltaic performance of organic solar cells(OSCs) based on non-fused ring electron acceptors(NFREAs).However,research on the impact of fluorination positions at side chains on NFREAs device performance remains scant.In this study,we introduce two isomeric NFREAs,designated as GA-2F-E and GA-2F,distinguished by their fluorination positions at the side chains.Both NFREAs share a thiophene[3,2-b]thiophene core,but their side chains differ:GA-2F-E features two(4-butylphenyl)-N-(4-fluorophenyl) amino groups,whereas GA-2F's side chains consist of bis(4-fluorophenyl)amino and bis(4-butylphenyl)amino groups attached to opposite sides of the core.To delve into the influence of fluorination positions on the optoelectronic properties,aggregation behavior,and overall efficiency of the acceptor molecules,a comprehensive investigation was conducted.The findings reveal that,despite similar photophysical properties and comparable absorption bandwidths,GA-2F-E,with fluorine atoms positioned on both sides of the molecular framework,demonstrates more compact π-π stacking,reduced bimolecular recombination,superior exciton transport,and a more balanced,higher mobility.As a result of these advantages,OSCs optimized with D18:GA-2F-E achieve a remarkable power conversion efficiency(PCE) of 16.45 %,surpassing the 15.83 %PCE of devices utilizing D18:GA-2F.This research underscores the potential of NFREAs in future applications and highlights the significance of fluorination positions in enhancing OSC performance,paving the way for the development of more efficient NFREAs.
