Planar heterojunction perovskite/PC71BM solar cells with enhanced open-circuit voltage via a (2/1)-step spin-coating process

A two-step, spin-coating process to synthesize a high quality perovskite film at room temperature at ambient atmosphere is reported. Combining an optimized PEDOT:PSS hole-transport layer and a PC71BM acceptor, the device achieved a power conversion efficiency of 16.31% with a remarkably high V-oc of 1.05 V and FF of 0.78. The efficiency reproducibility of the devices is also high: 80% of devices achieve efficiency higher than 15%.