Morphologic improvement of the P3HT: Indene-C60 bis-adduct(ICBA) blend film with mixed solvent in inverted polymer solar cells

To enhance the open circuit voltage, a new acceptor material Indene-C60 bisadduct (ICBA) has been reported. The published literatures have been reported that almost all groups dissolve the ICBA and P3HT in DCB. However, the solubility of ICBA in DCB is not good that results in high leaking current and lowers the open circuit voltage on inverted structure of polymer solar cells. We use mixed solvent of DCB and CB to improve the solubility of the active layer, add polymer polyvinylcarbazole (PVK) to reduce the horizontal phase separation, and control the dried time of active layer by using different ratio of DCB and CB. As a result, the open circuit voltage of inverted polymer solar cells is enhanced from 0.66V to 0.82V and the power conversion efficiency (PCE) enhance from 2.6% to 3.81%.