Highly Stable and Green-Emissive Copper-Based Metal Halide Perovskite Nanocomposite within a Metal–Organic Framework

The toxicity of lead-based perovskites significantly limits their optoelectronic applications, which has driven extensive research on nonlead-based metal halide luminescent materials. In this study, we synthesized Cu-based metal halide quantum dots (QDs) with improved stability using metal–organic frameworks (MOFs) as hard templates. RbCu2I3 was synthesized using UiO-66 as a template, and a stable perovskite precursor solution was developed. We obtained a precursor solution that remained stable under an ambient atmosphere by dissolving rubidium iodide and copper iodide. The RbCu2I3@UiO-66 nanocomposite exhibited a green emission at 518 nm under ultraviolet illumination. RbCu2I3@UiO-66 maintained its photoluminescence intensity even after 100 days of air exposure, indicating strong environmental stability. The enhanced stability compared to other copper-based metal halide materials is attributed to the MOF pores, which effectively confine the QDs and prevent their degradation. These findings indicate that MOF-templated synthesis is a promising approach for improving the stability and usability of luminescent metal halide materials.