Efficient and self-healing copper halide Cs3Cu2Cl5 film assisted by microwave treatment for high-resolution X-ray imaging

Lead-free Cs3Cu2Cl5 metal halide exhibits high photoluminescence quantum yield (PLQY), large Stokes shifts and small self-absorption due to self-trapped excitons (STE) emission, which undoubtedly is a potential scintillator material. However, Cs3Cu2Cl5 nanocrystals (NCs) are susceptible to degradation by moisture at high humidity environment, which severely affects its long-term application in X-ray imaging. Herein, we prepared Cs3Cu2Cl5 scintillator films with a PLQY of 72.4% and a high spatial resolution of 20 lp mm−1. Moreover, we firstly propose a self-healing strategy with facile microwave treatment to recover the crystal structure of Cs3Cu2Cl5 film which damaged by moisture, while the photoluminescence (PL) and radioluminescence (RL) intensities of the damaged Cs3Cu2Cl5 film are repaired to more than 95% and the spatial resolution can be restored to 20 lp mm−1. Furtherly, the imaging quality of the self-healing scintillator film can be maintained stably by cyclic microwave treatment. It found that microwave treatment provides a simultaneous and molecular level heating environment for the Cs3Cu2Cl5 film, which drives the hydrolysates to re-crystallize along with the surface of the destroyed crystals. Therefore, microwave treatment opens a new avenue to recover Cs3Cu2Cl5 films degraded by moisture, and provides a solution for long-term application of scintillator films at low cost.