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 (Jsc) changed depending on the solvent and cell composition. When the ratio of ICBA was higher than that of P3HT, a high Jsc was obtained from the CB based cells. When the ratio of P3HT was higher than that of ICBA, the CF cells showed a higher Jsc 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.