Tetradic phosphor white light with variable CCT and superlative CRI through organolead halide perovskite nanocrystals

In this work, the emission spectral range of halide perovskite nanocrystals is extended from violet to infrared, the widest emission range for halide perovskites to date. This range extension was made possible by a cost-effective solution-based synthesis process that only involves two halides [MAPb(Br I_1- )₃ and MA = CH₃NH₃]. Furthermore, the correlated-color temperature (CCT) of white light is tuned by blending an appropriate fraction of the as-synthesized blue, green, yellow, and red emitting nanocrystals. This represents one of the first applications of a tetradic phosphor system for maximizing the color rendering index (CRI) for this material. The CCT ranges from warm to cool white (2759-6398 K) and the CRI has a maximum value of 93.95. Thus, this fourfold phosphor approach demonstrates that halide perovskites are promising alternatives to conventional phosphors in the search for low-cost and high-quality white light sources in the next generation of white lighting technology.