Highly efficient emission and high-CRI warm white light-emitting diodes from ligand-modified CsPbBr3 quantum dots

All-inorganic CsPbBr3 perovskite quantum dots (QDs) have received great attention in white light emission because of their outstanding properties. However, their practical application is hindered by poor stability. Herein, we propose a simple strategy to synthesize excellent stability and efficient emission of CsPbBr3 QDs by using 2-hexyldecanoic acid (DA) as a ligand to replace the regular oleic acid (OA) ligand. Thanks to the strong binding energy between DA ligand and QDs, the modified QDs not only show a high photoluminescence quantum yield (PLQY) of 96% but also exhibit high stability against ethanol and water. Thereby warm white light-emitting diodes (WLEDs) are constructed by combining ligand modified CsPbBr3 QDs with red AgInZnS QDs on blue emitting InGaN chips, exhibiting a color rendering index of 93, a power efficiency of 64.8 lm/W, a CIE coordinate of (0.44, 0.42) and correlated color temperature value of 3018 K. In addition, WLEDs based on ligand modified CsPbBr3 QDs also exhibit better thermal performance than that of WLEDs based on the regular CsPbBr3 QDs. The combination of improved efficiency and better thermal stability with high color quality indicates that the modified CsPbBr3 QDs are ideal for WLEDs application.