Synthesis, Properties, and Photovoltaic Characteristics of Arch- and S-shaped Naphthobisthiadiazole-based Acceptors

Abstract

Fine-tuning physical properties by structural modification is important for developing organic semiconducting materials. In this work, we designed and synthesized new electron-accepting compounds containing naphtho[1,2-c:7,8-c']bis([1,2,5]thiadiazole (vNTz) or naphtho[1,2-c:5,6-c']bis[1,2,5]thiadiazole (NTz) groups as electron-accepting units; these units are structural isomers. The vNTz-based compounds have an arch-shaped molecular backbone with C2v symmetry, whereas the NTz-based compound forms an S-shaped molecular backbone with C2h symmetry. Property measurements showed unique behavior originating from the vNTz core. An organic solar cell comprising the vNTz-based compound and poly(3-hexylthiopehene) showed a power conversion efficiency of 2.06%. This result demonstrates the potential of vNTz as an electron-accepting unit in organic semiconducting materials.