Efficient all-polymer solar cells with a high open circuit voltage

As a star polymer acceptor, N2200 got great attention once emerging. However, some of its properties, like poor miscibility with donors, relatively deep lowest unoccupied molecular orbital (LUMO) energy level, restrict its application. In general, random copolymerization can be used to perform partial substitution in polymers to achieve simple performance regulation. In this work, we obtained a new acceptor polymer PNDIOD-30Se based on N2200 by partially replacing thiophene with selenophene. At optimal condition, the power conversion efficiency of the devices based on PTBD-BZ: PNDIOD-30Se was over to 6.42% with a high open circuit voltage of 0.91 V. The blend film was more uniform, and got nanophase separation domain. The results indicate that incorporating selenophene by random copolymerization into n-type polymer could simply adjust the properties of the polymer acceptor for all-polymer solar cells. • A new acceptor polymer PNDIOD-30Se based on N2200 was constructed by partially replacing thiophene with selenophene. • The polymer has a higher LUMO energy level and got a high open circuit voltage of 0.91 V blend with donor PTBD-BZ. • The PCE of the device based on PTBD-BZ/PNDIOD-30Se reached 6.42%. • Incorporating selenophene is an effective method to adjust the properties of N2200.