Vacuum-depositable thiophene- and benzothiadiazole-based donor materials for organic solar cells

Abstract

Three (D–A–D)-type electron donor materials, containing 2,1,3-benzothiadiazole as the electron-withdrawing core, and benzothiophene, naphthalene, and thiophene as electron-donating terminal groups, were synthesized for vacuum-depositable small-molecule organic solar cells. The donor material containing thiophene as the terminal group, DT, shows a maximum power conversion efficiency of 4.13%, a short-circuit current density of 9.89 mA cm⁻², an open-circuit voltage of 0.86 V, and a fill factor of 0.48, in a bulk heterojunction solar cell with a blend ratio of DT : C₇₀ = 1 : 4 under simulated AM 1.5 solar irradiation at 100 mW cm⁻².