Effect of co-solvents on the photovoltaic performance of an inverted organic solar cell

Abstract

We investigated the effect of varying polymer crystallinity, morphology, and optical property, produced by adding four different co-solvents in to the poly(3-hexylthiophene) (P3HT): [6,6]-phenyl C61-butyric acid methyl ester (PCBM) active layer blend solution, on the functioning of an inverted polymeric solar device. Photovoltaic devices primed with cyclohexanone co-solvent showed the best performance with power conversion efficiency (PCE) reaching a value of 3.01-±-0.04%. Improvement in efficiency is related to an increase in photocurrent which is due to a combined result of ordered P3HT crystallite growth, as well as of the precise size and phase separation of domains.