CsPbX3/LaPO4:Eu3+ Dual-Emission Composites with Stimuli-Responsive Fluorescence Switching for Advanced Anti-Counterfeiting

Abstract

All-inorganic metal halide perovskite CsPbX₃ (X = Cl, Br, I) quantum dots (QDs) hold great promise for optoelectronic applications due to their outstanding properties. The practical application of brilliant CsPbX₃ QDs is limited by their environmental instability. Here, we report a stability-enhanced dual-emission composite, fabricated by in-situ growth of CsPbBr₃ QDs on LaPO₄:Eu³⁺ microspheres. The host matrix serves as a physical barrier, effectively isolating the QDs from degradation and boosting their luminescence performance and robustness. This composite features excitationdependent fluorescence, enabling a dynamic "optical switch" for information encryption-demonstrated by an "NCU" tag and an ASCII binary code system.Additionally, the divergent thermal quenching behaviors of the two components offer avenues for developing optical temperature sensors.