Perovskite quantum dot-coated YAG:Ce composites for warm white light-emitting diodes

Widespread application of YAG:Ce-based white light-emitting diodes (WLEDs) is being challenged due to the lack of red emission, leading to their poor color rendering index (Ra) and high correlated color temperature (CCT). Perovskite quantum dots (QDs), presenting high photoluminescence quantum yield and simple fabrication process have been recognized as promising red-emitting component for warm WLEDs. However, conventional method by mechanically mixing QDs with YAG:Ce always results in undesirable dispersion due to their huge size difference. Moreover, the two components display different sinking behavior in silicone, which would further deteriorate the color uniformity of WLED. To address these issues, in this study, red-emitting MAPbBr3-xIx QDs-coated YAG:Ce (A-YAG@QDs) composites were successfully prepared to further fabricate WLED with compensated red emission. The chemical coordination interactions between QDs and functionalized YAG:Ce make the two components behave as a whole, which effectively avoids the dispersion and sinking-related issues. The WLED, which combined blue LED chip and A-YAG@QDs composite, exhibited warm white light with low CCT of 4474 K, high Ra of 90.1 and high value of saturated red color component R9 as 95. This study demonstrated a promising strategy to prepare QDs-coated phosphor composites for the generation of warm white light for indoor lighting application.