Propeller-Shaped Acceptors for High-Performance Non-Fullerene Solar Cells: Importance of the Rigidity of Molecular Geometry

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• 作者：Qinghe WuDonglin Zhao ; Jinghui Yang ; Valerii Sharapov ; Zhengxu Cai ; Lianwei LiNa Zhang ; Andriy NeshchadinWei Chen ; Luping Yu
• 刊名：Chemistry of Materials
• 出版年：2017
• 出版时间：February 14, 2017
• 年：2017
• 卷：29
• 期：3
• 页码：1127-1133
• 全文大小：584K
• ISSN：1520-5002

文摘

This paper describes the synthesis and application of βTPB6 and βTPB6-C as electron acceptors for organic solar cells. Compound βTPB6 contains four covalently bonded PDIs with a BDT-Th core at the β-position. The free rotation of PDIs renders βTPB6 with varying molecular geometries. The cyclization of βTPB6 yields βTPB6-C with high rigidity of the molecular geometry and enlarged conjugated skeleton. The inverted solar cells based on βTPB6-C and PTB7-Th as the donor polymer exhibited the highest efficiency of 7.69% with V_oc of 0.92 V, J_sc of 14.9 mAcm^–2, and FF of 0.56, which is 31% higher than that for βTPB6 based devices. The larger fraction of βTPB6-C and PTB7-Th than that of βTPB6:PTB7-Th in a blend film takes a face-on orientation packing pattern for π-systems that benefits the charge transport and hence higher PCE value than that for βTPB6:PTB7-Th. It was also found that a proper DIO:DPE additive further enhances this trend, which results in an increase of the PCE value for βTPB6-C:PTB7-Th while decreasing the PCE value for βTPB6:PTB7-Th.