Interfacial‐Field‐Induced Increase of the Structural Phase Transition Temperature in Organic–Inorganic Perovskite Crystals Coated with ZnO Nanoshell

Abstract The hybrid organic–inorganic perovskites are known to exhibit a complex crystalline structure, which allows for the structural phase transitions among the orthorhombic, tetragonal, and cubic phases that occur at different temperatures. This behavior of the organic–inorganic perovskites can significantly alter their optoelectronic properties. Here, using photoluminescence spectroscopy, it is shown that the structural orthorhombic‐to‐tetragonal phase transition temperature in MAPbI₃ perovskite crystal can be increased from 135 to 160 K upon coating with ZnO nanoshell. The phenomenon is attributed to the interfacial‐field‐induced atomic rearrangement in the near‐surface area. The findings shed light on the great importance of the interfacial electric field effect on the structural and optical properties of the organic–inorganic perovskites, which hold great promise for their potential applications in the structural‐phase‐controlled optoelectronic and photovoltaic devices.