摘要
Small molecular acceptors(SMAs)BTC-2F and BTH-2F,based on heptacyclic benzodi(cyclopentadithiophene)electron-donating core(CBT)with chlorinated-thienyl conjugated and thienyl conjugated side chains,respectively,are designed and synthesized.Compared with non-chlorine acceptor BTH-2F,BTC-2F exhibits slightly blue-shifted absorption spectra,similar the lowest unoccupied molecular orbital(LUMO)(-3.91 eV);deeper highest occupied molecular orbital(HOMO)energy level and higher electron mobility than that of BTH-2F.PM6,a wide bandgap polymer,is selected as the donor material to construct bulk heterojunction polymer solar cells processed with nonhalogenated solvent toluene.The optimized PM6:BTC-2F-based device presents a 12.9%power conversion efficiency(PCE),while the PCE of PM6:BTH-2F-based device is only 11.3%.The results suggest that it is an effective strategy to optimize the photoelectric properties of SMAs by incorporating chlorine atom into the conjugated side chains.
基金
the National Natural Science Foundation of China(NSFC)(Nos.51503135,51573120,21734009 and 91633301)
Jiangsu Provincial Natural Science Foundation(Grant No.BK20150332)
Collaborative Innovation Center of Suzhou Nano Science&Technology
The GIWAXS and RSoXS of this research were carried out at beamline 7.3.3 and 11.0.1.2 at the Advanced Light Source,Molecular Foundry
National Center for Electron Microscopy,Lawrence Berkeley National Laboratory,which was supported by the DOE,Office of Science,and Office of Basic Energy Sciences.
