Achieving Tunable Cold/Warm White-Light Emission in a Single Perovskite Material with Near-Unity Photoluminescence Quantum Yield

Highlights High-quality Sn 2+ /Mn 2+ -co-doped Rb 4 CdCl 6 single crystals and powders were prepared and showed high-performance dual-emission white light with near-unity photoluminescence quantum yield. Short-range and extremely strong interactions between Sn 2+ and Mn 2+ were observed that lead to an intriguing ultra-high-efficiency Dexter energy transfer process from adjacent Sn 2+ ions to Mn 2+ ions. The dual-emission intensities were tuned flexibly by varying the fractions of Sn 2+ and Sn–Mn pairs to balance their emission proportions for cold/warm white-light generation.