Lead-Free Nanostructured Cs ₃ Cu ₂ Cl ₅ /PMMA Films for Flexible Light-Emitting Applications

To solve the problem of the toxicity and photoluminescence (PL) instability from the Pb-based perovskites, the lead-free Cs 3 Cu 2 Cl 5 nanocrystals were synthesized via a hot-injection method, followed by the fabrication of the Cs 3 Cu 2 Cl 5 /PMMA films through in situ poly(methyl methacrylate) (PMMA) encapsulation. The Cs 3 Cu 2 Cl 5 nanocrystals were uniformly dispersed in the PMMA matrix to improve environmental stability and mechanical flexibility. The experimental results show that the Cs 3 Cu 2 Cl 5 /PMMA films exhibit significantly enhanced photoluminescence (PL) intensity and prolonged carrier lifetime, which can be attributed to the quantum confinement effect and interfacial coupling. This work demonstrates a feasible strategy for constructing stable, environmentally benign, and flexible nanostructured perovskite materials, offering great potential for next-generation light-emitting diodes (LEDs), display technologies, and wearable optoelectronic devices.