Large-Scale Ligand-Free Synthesis of Homogeneous Core-Shell Quantum-Dot-Modified Cs₄PbBr₆ Microcrystals

An organic ligand-free solution method is developed for preparing homogeneous core-shell quantum-dot (QD)-modified pure Cs₄PbBr₆ microcrystals on a large scale (∼12 g) at room temperature. The ligand-free Cs₄PbBr₆ microcrystals show a high green photoluminescence quantum yield of 76% with 360 nm of excitation light, which is attributed to their unique microarchitecture, with several features including quantum confinement of the outer QDs, stability of the inner Cs₄PbBr₆ microcrystals, improved light trapping, and interfacial recombination. UV-vis-near-IR and photoluminescence analyses provide valued evidence to support the ligand-free Cs₄PbBr₆ with synergy between the QDs and microcrystals.