Control of <i>I</i>–<i>V</i> Hysteresis in CH₃NH₃PbI₃ Perovskite Solar Cell

TLDR

I‑V hysteresis in MAPbI₃ perovskite solar cells is a critical issue, yet its origin remains unresolved despite proposed ferroelectric and ion‑migration mechanisms. The study aims to determine the origin of I‑V hysteresis in MAPbI₃ perovskite solar cells. This was done by systematically evaluating interface‑dependent electrode polarizations. Capacitance measurements show that TiO₂ layers dominate hysteresis, while replacing TiO₂ with PCBM and adding PEDOT:PSS, NiO, and PCBM layers reduces capacitance to 10⁻⁵ F cm⁻² and shifts the C–f response, offering a route to eliminate hysteresis.

Abstract

Mismatch of current (I)-voltage (V) curves with respect to the scan direction, so-called I–V hysteresis, raises critical issue in MAPbI3 (MA = CH3NH3) perovskite solar cell. Although ferroelectric and ion migration have been proposed as a basis for the hysteresis, origin of hysteresis has not been apparently unraveled. We report here on the origin of I–V hysteresis of perovskite solar cell that was systematically evaluated by the interface-dependent electrode polarizations. Frequency (f)-dependent capacitance (C) revealed that the normal planar structure with the TiO2/MAPbI3/spiro-MeOTAD configuration showed most significant I–V hysteresis along with highest capacitance (10–2 F/cm2) among the studied cell configurations. Substantial reduction in capacitance to 10–3 F/cm2 was observed upon replacing TiO2 with PCBM, indicative of the TiO2 layer being mainly responsible for the hysteresis. The capacitance was intensively reduced to 10–5 F/cm2 and C–f feature shifted to higher frequency for the hysteresis-free planar structures with combination of PEDOT:PSS, NiO, and PCBM, which underlines the spiro-MeOTAD in part contributes to the hysteresis. This work is expected to provide a key to the solution of the problem on I–V hysteresis in perovskite solar cell.