摘要
In this study,wide bandgap(WBG)two-dimensional(2D)copolymer donors(DZ1,DZ2,and DZ3)based on benzodithiophene(BDT)on alkoxyphenyl conjugated side chains without and with different amounts of chlorine atoms and difluorobenzotriazole(FBTZ)are designed and synthesized successfully for efficient non-fullerene polymer solar cells(PSCs).Three polymer donors DZ1,DZ2,and DZ3 display similar absorption spectra at 300-700 nm range with optional band-gap(Egopt)of 1.84,1.92,and 1.97 eV,respectively.Compared with reported DZ1 without chlorine substitution,it is found that introducing chlorine atoms into the meta-position of the alkoxyphenyl group affords polymer possessing a deeper the highest occupied molecular orbital(HOMO)energy level,which can increase open circuit voltage(Voc)of PSCs,as well as improve hole mobility.Non-fullerene bulk heterojunction PSCs based on DZ2:MelC demonstrate a relatively high power conversion efficiency(PCE)of 10.22%with a Voc of 0.88 V,a short-circuit current density(Jsc)of 17.62 mA/cm^2,and a fill factor(FF)of 68%,compared with PSCs based on DZ1:MelC(a PCE of 8.26%)and DZ3:MelC(a PCE of 6.28%).The results imply that adjusting chlorine atom amount on alkoxyphenyl side chains based on BDT polymer donors is a promising approach of synthesizing electron-rich building block for high performance of PSCs.
基金
This work was financially supported by the National Natural Science Foundation of China(Nos.51763017,21602150,51425304,51863012,21861025,51833004)
the Shen Zhen Technology and Innovation Commission(Nos.JCYJ20170413173814007,JCYJ20170818113905024)
the Hong Kong Research Grants Council(Research Impact Fund R6021-18,Nos.16305915,16322416,606012,16303917)
Hong Kong Innovation and Technology Commission for the support through projects ITC-CNERC14SC01 and ITS/471/18,the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIP)(No.2018R1A2A1A05077194)
Wearable Platform Materials Technology Center(WMC
No.2016R1A5A1009926)funded by the National Research Foundation of Korea(NRF)Grant by the Korean Government(MSIT)
the Research Project Funded by Ulsan City(No.1.200042)of UNIST(Ulsan National Institute of Science&Technology).
