Probing surface dipole effects on perovskite photocurrent hysteresis through in-situ characterization

This study explored the impact of two dipole molecules, 4-nitrobenzoic acid and 4-aminobenzoic acid, on the electronic properties of MAPbI3 perovskite. Significant changes in the work function were observed upon molecular adsorption, with 4-nitrobenzoic acid increasing the work function and 4-aminobenzoic acid decreasing it. The lock-in amplifier based surface photovoltage spectroscopy measurements revealed that 4-nitrobenzoic acid decreased surface photovoltage, while 4-aminobenzoic acid increased it. Furthermore, in-situ conductive-atomic force microscopy analysis indicated pronounced photocurrent hysteresis with 4-aminobenzoic acid and reduced hysteresis with 4-nitrobenzoic acid. This study underscores the critical role of surface dipoles in manipulating perovskite charge transfer and provides valuable insights into the mechanisms behind photocurrent hysteresis.