Marked effects of indolyl vs. indolinyl substituent on solid-state structure, carrier mobility and photovoltaic efficiency of asymmetrical squaraine dyes

作者：Yang Lin; Yang Qianqian; Yang Daobin; Luo Qian; Zhu Youqin; Huang Yan^*; Zhao Suling; Lu Zhiyun

来源：Journal of Materials Chemistry A, 2014, 2(43): 18313-18321.

DOI：10.1039/c4ta03859b

Two solution-processed asymmetrical squaraines (ASQs) with cyclopenta[b] indolinyl (1a) and cyclopenta[b] indolyl (1b) as end cappers have been designed and synthesized. Although the internal molecular structure variations are minimal, the presence of the cyclopenta[b] indolinyl group endows 1a more planar molecular structure, which results in a much more compact solid-state structure (density is 1.317 g cm(-3) for 1a but is 1.187 g cm(-3) for 1b), dramatically affecting charge transport in the thin films. The hole mobility of 1a: PC71BM blended film is about 7 times higher than that of 1b: PC71BM. Consequently, the maximum power conversion efficiency (PCE) value of the organic photovoltaic cells (OPVs) based on 1a of up to 4.1%, approximately 80% higher than that of 1b, is one of the highest PCEs achieved for ASQ-based bulk-heterojunction (BHJ) OPVs.

• 出版日期2014
• 单位四川大学; 北京交通大学