Figure 1: Structures, electrical and optical properties of ternary blends.

(a) Molecular structures of PID2, PTB7-Th and PC71BM. (b) Energy levels of materials used in the solar cell device. (c) UV–vis absorption spectra of PTB7-Th and PID2 in chloroform. (d) UV–vis absorption spectra of PTB7-Th:PID2:PC71BM films with different PTB7-Th:PID2 weight ratios.