Vasquez-Montoya, M.F.; Simmonds, M.; Li, J.; Dzhong, A.; Gries, T.W.; Chemin, A.; Petit, T.; Holzhey, P.; Albrecht, S.; Trofimov, S.; Naydenov, B.; de Van de Krol, R.; Favaro, M.; Unger, E.: Photodegradation of 2D Ruddlesden-Popper Perovskites: Consequences and Design Principles for Photoelectrochemical Applications. Advanced Science 12 (2025), p. e07300/1-10
10.1002/advs.202507300
Open Accesn Version
Abstract:
Halide perovskites (HaP), with their exceptional optoelectronic properties and high-power conversion efficiencies in photovoltaic devices, hold promise for photoelectrochemical (PEC) applications in green fuel and chemical production. However, their stability in aqueous environments remains a challenge. This study investigates the stability and degradation mechanisms of the 2D Ruddlesden-Popper phase phenylethyl ammonium lead iodide (PEA(+)2PbI4) thin films in aqueous electrolytes under dark and illuminated conditions. While PEA(+)2PbI4 thin films appear to be thermodynamically stable in an aqueous electrolyte with phenylethyl ammonium iodide (PEAI), illumination causes significant photodegradation generating a deprotonated and dehalogenated 2D intercalation product: phenylethylamine-lead iodide, 2PEA(0)-PbI2. The degradation of the 2D semiconductor leads to substantial reduction in the photovoltage, adversely impacting the material performance in photoelectrochemical (PEC) devices. To intercept photo-excited charge carriers in the 2D semiconductor, the I3−/I− redox is added, which reduced photodegradation. The findings underscore that while catalytic reactions at halide perovskite electrodes in aqueous electrolytes are feasible, reversible and irreversible photodegradation remains a critical limitation that must be addressed in the design of PEC devices employing metal halide semiconductor layers for direct electrochemical energy conversion.