Water-assistant ultrahigh fluorescence enhancement in perovskite polymer-encapsulated film for flexible X-ray scintillators

Abstract

Methylammonium lead halide perovskites are well-known having a poor stability towards moisture. Water causes degradation of ionic perovskites and weaken the optical and electronic performance of perovskite-based devices. Main strategies to improve moisture stability are compositional engineering, surface engineering and matrix encapsulation. Herein, encapsulation strategy is implemented through screening a polymer matrix, a hydrophobic room-temperature vulcanized silicone rubber (RTV-2). Owing to the positive effect of moderate water on the performance of perovskites, the obtained MAPbBr3/RTV-2 composite film is processed with water post-treatment to undergo surface engineering. The composite film achieves a remarkable 8-fold fluorescence enhancement. Luminous efficiency of the film loaded on a 380 nm chip is improved from 51.4 lm/W to 135.37 lm/W. The flexible MAPbBr3/RTV-2 film responds sensitively under X-ray irradiation. Its detection limit is down to 12 nGyair s−1, 400 times lower than the regular dosage in X-ray diagnostics (5.5 μGy s−1). These results provide guidance to design perovskite-based devices with bright luminescence and excellent flexibility to qualify the wearable X-ray detectors for dose monitoring.