Effect of solvent and cell composition on morphology and photovoltaic characteristics of polymer solar cells of poly(3-hexylthiophene)/indene-C60 bisadduct composites

This study investigated the solvent effect on the performance of polymer solar cells (PSCs) by focusing on the film morphology. PSCs consisting of poly(3-hexylthiophene) (P3HT) and the fullerene derivative indene-C60 bisadduct (ICBA) were fabricated using two different solvents, chlorobenzene (CB) and chloroform (CF). The short-circuit current density (J(sc)) changed depending on the solvent and cell composition. When the ratio of ICBA was higher than that of P3HT, a high J(sc) was obtained from the CB based cells. When the ratio of P3HT was higher than that of ICBA, the CF cells showed a higher J(sc) than the CB cells. The high-performance cells had a clear microphase-separated morphology while phase separation was limited in the low-performance cells. Solubility parameter analysis suggested that the cell composition changed the interaction parameter of the system and thereby affected the phase separation behavior. (C) 2017 The Japan Society of Applied Physics