Enhancing the performance of perovskite solar cell via PVA modification to NiOx hole transport layer

Nickel oxide (NiOx) has been widely used as a hole transport layer (HTL) of p-i-n type perovskite solar cells (PSCs) because of its many unique properties. However, the poor contact between NiOx and perovskite is disadvantage to the fabrication of high-quality perovskite film, which has bad effect on the open-circuit voltage (V-OC), short-circuit current density (J(SC)) and fill factor (FF) of PSCs. In this report, poly(vinyl alcohol) (PVA) was used as a modifier on the surface of NiOx. Experimental results showed that after PVA modification the PCE of PSCs increased significantly from 16.79% to 19.17% due to the increase of J(SC) and FF. The MAPbI(3) film on top of the PVA modified NiOx showed larger crystal size, less defect intensity and higher hole mobility. The work mechanism of PVA modification was investigated. This work provides an effective and simple method to improve the performance of PSCs.