Polymer solar cells(PSCs)consisting of a polymer donor and a small molecular acceptor is a promising photovoltaic technology,whose device performance is determined by both polymer donor and small molecular acceptor.Ha...Polymer solar cells(PSCs)consisting of a polymer donor and a small molecular acceptor is a promising photovoltaic technology,whose device performance is determined by both polymer donor and small molecular acceptor.Halogen atoms such as fluorine or chlorine atoms were usually introduced onto the polymer donors to downshift the highest occupied molecular orbital(HOMO)energy levels and improve the open-circuit voltage(VOC)of the PSCs.However,the introduction of the halogen atoms especially fluorine atoms greatly complicates the polymer synthesis.Herein,we report the use of a structural simple and easily synthesized building block,3,4-dicyanothiophene(DCT),to construct a set of halogen-free polymer donors PBCNTx(x=25,50,75)via ternary random copolymerization.The introduction of DCT units not only simplified the synthesis,but also downshifted the HOMO energy levels of the polymers and improved the V_(OC) of PSCs effectively.Encouragingly,the PBCNT75 afforded a power conversion efficiency up to 15.7%with a V_(OC) of 0.83 V,which are among the top values for halogen-free polymer donors.This work shows that the introduction of DCT units is a simple yet effective strategy to construct halogen-free and low-cost polymer donors for high-performance PSCs.展开更多
基金The work was financially supported by the Ministry of Science and Technology of China(Nos.2017YFA0206600 and 2019YFA0705900)the National Natural Science Foundation of China(Nos.21875072,U20A6002 and 51973169)+2 种基金Guangdong Innovative and Entrepreneurial Research Team Program(No.2019ZT08L075)This study also received financial support from Science and Technology Foundation of Guangdong Province(No.2021A0101180005)Special Projects in Key Areas for the University of Guangdong Province(No.2021ZDZX1009).
文摘Polymer solar cells(PSCs)consisting of a polymer donor and a small molecular acceptor is a promising photovoltaic technology,whose device performance is determined by both polymer donor and small molecular acceptor.Halogen atoms such as fluorine or chlorine atoms were usually introduced onto the polymer donors to downshift the highest occupied molecular orbital(HOMO)energy levels and improve the open-circuit voltage(VOC)of the PSCs.However,the introduction of the halogen atoms especially fluorine atoms greatly complicates the polymer synthesis.Herein,we report the use of a structural simple and easily synthesized building block,3,4-dicyanothiophene(DCT),to construct a set of halogen-free polymer donors PBCNTx(x=25,50,75)via ternary random copolymerization.The introduction of DCT units not only simplified the synthesis,but also downshifted the HOMO energy levels of the polymers and improved the V_(OC) of PSCs effectively.Encouragingly,the PBCNT75 afforded a power conversion efficiency up to 15.7%with a V_(OC) of 0.83 V,which are among the top values for halogen-free polymer donors.This work shows that the introduction of DCT units is a simple yet effective strategy to construct halogen-free and low-cost polymer donors for high-performance PSCs.
