[25a-E206-1~9] 12.5 Organic solar cells

[25a-E206-3] Impact of Backbone Linkage Pattern on the Structural Order and Photovoltaic Properties in Thiazole-Based Polymers

〇Yoshikazu Teshima¹, Masahiko Saito¹, Tsubasa Mikie¹, Itaru Osaka¹ (1.Hiroshima Univ.)

Keywords:Organic photovoltaic, Semiconducting polymer, non-fullerene

Recently, the power conversion efficiency (PCE) of organic photovoltaics has remarkably improved by the development of non-fullerene acceptors (NFA). In NFA-based cells, polymer donors with low crystallinity are typically used and afford high PCEs. Here, apart from such low-crystalline polymers, we designed and synthesized new crystalline polymers by combining dialkyl-bithiophene and bithiazole, more specifically, 2,2′-bithiazole or 5,5′-bithiazole in the backbone. The polymer with 5,5′-bithiazole showed relatively high PCE of 12%, which was high for polymer donors based on non-fused rings, indicating that crystalline polymers can function in NFA-based cells. We also found that the linkage pattern of bithiazole significantly affects the polymer thin-film structure and photovoltaic performance.