Influence of Hole Transport Layers/Perovskite Interfaces on the Hysteresis Behavior of Inverted Perovskite Solar Cells

A nickel oxide (NiOx) film is employed to replace poly(2,-dihydrothieno-1,4-dioxin)-poly(styrene sulfonate) (PEDOT:PSS) as the hole transport layer for inverted perovskite solar cells (PSCs) with zinc oxide as the electron transport layer, and we focus on the influence of the interface between the hole transport layer and the perovskite layer on carrier transport. The space-charge-limited current measurement and steady-state and time-resolved photoluminescence (PL) spectra indicate that the perovskite film deposited on the NiOx film has a smaller trap density than that on a PEDOT:PSS film. Additionally, the enhanced PL intensity and longer carrier lifetime imply that the perovskite film deposited on the NiOx film has poor carrier extraction efficiency, which likely results from the vast carrier accumulation at the interface. The NiOx-based PSCs show a reduced hysteresis behavior compared to the PEDOT:PSS-based PSCs, which implies that reducing the trap density in the perovskite film likely contributes more to reducing the hysteresis behavior than reducing carrier accumulation at the interface.