Introduction thioindigo as new high stability unit in Ru-complex for DSSCs: Theoretical and photovoltaic investigation

Abstract

New Ru-dyes were designed with indoline and thioindigo groups for dye-sensitized solar cells (DSSCs). Thioindigo was used as an effective substitute for improving fastness properties, and the synthesis efficiency of dyes 1 and 2 was 78 and 82 %, respectively. Cyanoacrylic acid is a suitable electron-withdrawing group in the preparation of photosensitizers, which improved the conversion efficiency by about 88 % in this research. The optical response of the complexes was evaluated theoretically and experimentally. The presence of cyano groups effectively bonds with the semiconductor layer, resulting in a better photovoltaic response. Furthermore, the prepared complexes have two types of electron withdrawing groups, carboxylic acid and cyanoacrylic acid, which yield 3.29 % and 6.23 % efficiency, respectively. In addition, co-sensitization using two prepared complexes and N719 was studied and analyzed. The efficiency of DSSCs prepared with N719 and complexes 1 and 2 was 8.10 and 9.49 %, respectively.