Enhancing the thermal stability of the NIR emitting A2InCl5·H2O:Cr3+ phosphor based on A site regulation

Abstract

Component modulation strategies are widely used to modulate the PL properties of fluorescent materials. Metal halide perovskites (MHPs) have many advantages for optical applications, one of which is the excellent structural tunability. In this work, a series of Cs₂InCl₅·H₂O:xCr³⁺ phosphors were synthesized by a simple hydrothermal method, obtaining a broadband near-infrared (NIR) emission in the 800–1200 nm range with a peak at 910 nm under 360 nm excitation. Unlike the widely used B-site cation modulation, co doping Rb⁺/K⁺ at A sites improves the structural rigidity and thus enhances the emission intensity and luminescence thermal stability of the Cs₂InCl₅·H₂O:Cr³⁺ phosphor. In particular, the emission intensity of (Cs_0.7K_0.3)₂InCl₅·H₂O:0.25Cr³⁺ at 125 °C can retain 52% of that at room temperature. Due to its excellent performance, the (Cs_0.7K_0.3)₂InCl₅·H₂O:0.25Cr³⁺ phosphor in combination with 380 nm ultraviolet chips shows potential applications in non-destructive testing and night vision. This strategy provides new ideas for the modulation of MHP-based fluorescent materials in the future.