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

• Published in: Dyes and pigments Vol. 147; pp. 183 - 189
• Main Authors: Chen, Xianjie, Feng, Huanran, Lin, Zhijing, Jiang, Zhaowei, He, Tian, Yin, Shouchun, Wan, Xiangjian, Chen, Yongsheng, Zhang, Qian, Qiu, Huayu
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-12-2017
• Subjects: Dithienosilole; End-capped group; Morphology; Organic solar cell; Small molecules; Small molecules; Dithienosilole; Organic solar cell; Morphology; End-capped group
• ISSN: 0143-7208; 1873-3743
• DOI: 10.1016/j.dyepig.2017.07.059

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 (Jsc) 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 Jsc of 1.82 mA cm−2, which are mainly due to its poor morphology of active layers.
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•Two new small molecules with DTS as a core unit and different end-capped groups were reported.•DINDTS and DINCNDTS show broad absorption in the visible and near infrared region with absorption edges reaching 754 and 894 nm, respectively.•The optimized DINDTS-based device achieved a PCE of 6.60%. However, the DINCNDTS-based device achieved a low PCE of 0.58%.