Utilizing polymerizable ammonium as an A-site cation to improve the stability of Mn-based perovskites in humid environments

Abstract

Mn-based metal halide scintillators have emerged as a promising candidate for scintillators in X-ray imaging with attractive photophysical properties, a tunable structure, cost-efficient synthesis, and low toxicity. However, their poor stability in humid environments severely limits their further application. Herein, a polymerizable cation, methacryloyloxyethyltrimethyl ammonium (MAc⁺), has been introduced as an A-site cation in Mn-based metal halides to obtain an original Mn-based metal halide scintillator, MAc₂MnBr₂Cl₂. The novel Mn-based metal halide scintillator exhibits a superior photoluminescence quantum yield (PLQY) of 79.05%. The average particle size of MAc₂MnBr₂Cl₂ is tuned to the micrometer scale by carefully selecting the processing solvents, resulting in a spatial resolution of the MAc₂MnBr₂Cl₂ screen as high as 24 lp mm⁻¹. The A-site polymerizable cations were copolymerized with hydrophobic matrix monomers, butyl methacrylate (BMA) and trimethylolpropane triacrylate (TMPTA), to fabricate a hybrid scintillation screen, which can significantly improve the stability of the MAc₂MnBr₂Cl₂ hybrid scintillation screen in a humid environment. The photoluminescence (PL) intensity of the scintillation screen remains over 98% at an 85% relative humidity (RH) for over 24 hours. Even after being fully immersed in water for over 24 hours, the screen could still perform underwater X-ray imaging. This work provides a new method to greatly improve the water resistance of a Mn-based metal halide scintillator and potentially extends its application for underwater X-ray imaging.