Impact of end-capped groups on the properties of dithienosilole-based small molecules for solution-processed organic solar cells

摘要

Two new acceptor-donor-acceptor small molecules DINDTS and DINCNDTS, with dithienosilole as a core unit and 1,3-indanedione (IN) or malononitrile derivative 1,3-indanedione (INCN) units as end-capped groups, respectively, have been designed and synthesized for solution-processable bulk-heterojunction (BHJ) solar cells. The impact of these two end-capped groups on their optical, electrochemical properties and photovoltaic performance was systematically studied. The optimal DINDTS:PC71BM based solar cells showed a short-circuit current density (J(sc)) of 13.50 mA cm(-2) and power conversion efficiency (PCE) of 6.60%. However, DINCNDTS:PC71BM based devices exhibited a poor PCE of 0.58% with a very low J(sc) of 1.82 mA cm(-2), which are mainly due to its poor morphology of active layers. (C) 2017 Elsevier Ltd. All rights reserved.