Influence of mixed solvent on the morphology of the P3HT:Indene-C60 bisadduct (ICBA) blend film and the performance of inverted polymer solar cells

A new acceptor material, Indene-C60 bisadduct (ICBA), has reportedly improved the open circuit voltage. The published literature has reported that almost all groups dissolve the ICBA and P3HT in DCB. Nevertheless, the solubility of ICBA in DCB is poor, leading to high leakage current and lower open circuit voltage. To enhance the solubility of ICBA in photoactive ink, we use CB and DCB as a mixed solvent to fabricate the inverted polymer solar cells. We then add conductive polymer polyvinylcarbazole (PVK) to reduce the horizontal phase separation and control the drying time of the active layer by adjusting the ratios of DCB and CB. As a result, the open circuit voltage of inverted polymer solar cells is enhanced from 0.66 V to 0.82 V and the power conversion efficiency (PCE) improve from 2.6% to 4.27%.