Manipulating the photovoltaic properties of small-molecule donor materials by tailoring end-capped alkylthio substitution
Yue Wu a, Xiao Cheng a, Guiying Xu a, Yaowen Li a , Chaohua Cui*a（崔超华）and Yongfang Liab
a State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, Laboratory of Advanced Optoelectronic Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China
b Beijing National Laboratory of Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, P. R. China
RSC Adv., 2016,6, 108908-108916
The engineering of alkylthio side chains is a smart and effective strategy to improve the photovoltaic properties of donor materials for organic solar cells (OSCs). In order to further exploit the capability of alkylthio chains in tuning the physicochemical and photovoltaic properties of small-molecule donor materials, two small molecules DTS-BTT-S and BDTT-BTT-S with alkylthio end groups were designed and synthesized. The DFT calculation results reveal that introducing alkylthio end groups in DTS-BTT-S and BDTT-BTT-S effectively down-shifted the HOMO energy levels in comparison with their analogous molecules with alkyl end groups. The DTS-BTT-S based OSC device exhibited a higher Voc of 0.840 V, with a PCE of 3.65% without the need of extra-treatments of the active layer. The optimized device based on BDTT-BTT-S showed a higher PCE of 5.21%, with Voc = 0.823 V, Jsc = 10.93 mA cm−2 and FF = 57.2%.
链接：http://pubs.rsc.org/en/content/articlelanding/2016/ra/c6ra23898j#!divAbstract