Strategies for Enhancing the Stability of High-Electric-Field Perovskite Single-Crystal Radiation Detectors.

While a high electric field enhances the sensitivity and response speed of MAPbBr3 single-crystal radiation detectors, it also triggers interfacial electrochemical corrosion and ion migration, compromising device stability. This study reveals that multivalent titanium ion (Ti4+) migration in MAPbBr3 single-crystal radiation detectors at a high electric field requires grain boundary (GBs) assistance and is confined to the polycrystalline regions, located hundreds of nanometers from the crystal surface. Consequently, device performance can be fully restored by removing the corroded surface and redepositing the electrode. Furthermore, our results also illustrate that humidity and oxygen in the atmosphere can accelerate the electrochemical reaction at the Ti/perovskite single-crystal interface, highlighting the importance of encapsulation for perovskite single-crystal-based devices.