Influence of Solvent and Post-thermal Treatment on a Photovoltaic Cell with Blends of Self-organizing Poly(3-hexylthiophene) and Fullerene

Abstract

Organic photovoltaic cells based on poly(3-hexylthiophene) (P3HT):[6,6]-C61-butyric acid methyl ester (PCBM) were fabricated by using two different solvents. The photo-induced current; and the open-circuit voltage (V-oc) show a strong dependence oil the polymer processing conditions. We found that the photovoltaic devices fabricated with the non-aromatic solvent chloroform (hereafter CF) have smaller photocurrents under the same reverse bias and higher V-oc than the devices fabricated with the aromatic solvent chlorobenzene (hereafter CB). After post-thermal treatment, a strongly enhanced photo-induced current was observed in photovoltaic devices fabricated with CF and a slight photocurrent change was observed in the devices fabricated with CB. The dependence oil the solvent and the post-thermal treatment was attributed to the different morphology of solvation-induced interpenetrating network.