Syntheses and Photovoltaic Properties of Octyl Cyanoacetate Terminated Small Molecules Based on Benzo[1,2-b:4,5-b']dithiophene for OPVs

There have been tremendous efforts to synthesize photoactive materials that are consisted of both donor and acceptor components together to increase the power conversion efficiency (PCE) of organic photovoltaic cells (OPVs). In order to improve the performance of the OPVs, in this study, we proposed new A-D-A (Acceptor-Donor-Acceptor) type small molecular donors based on the donor unit of benzo[1,2-b:4.5-b’]dithiophene (BDT) with an acceptor unit of alkyl cyanoacetate. We characterized prepared photoactive materials using 1H NMR spectroscopy, DSC, CV (cyclic voltammetry), and UV/Vis spectroscopy. We also investigated the relationship between PCEs of OPVs and the active materials with variation of substituted methyl groups. The OPVs based on synthesized photoactive materials with different methyl substitutions showed different PCEs. Our results indicate that synthesized small molecular donor materials are promising donor materials for performance OPVsThis work was supported by New and Renewable Energy Program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Ministry of Trade, Industry & Energy (MTIE) (20113030010030)