Enhanced Luminescence of CsPbBr₃ Quantum Dot Glass through Eu³⁺–Rb⁺ Codoping

All-inorganic lead halide perovskite quantum dots (CsPbX3 QDs, X = Cl, Br, I) glass has elicited extensive attention due to its excellent stability. However, the realization of CsPbX3 QDs glasses with a high photoluminescence quantum yield (PLQY) remains a challenging task. In this study, Eu3+ ions act as nucleating agents to promote the formation and crystallization of CsPbBr3 QDs. Rb+ ions further improve the crystallization quality and reduce the defects between CsPbBr3 QDs and the glass interface. The codoping of Eu3+ and Rb+ ions greatly improved the PLQY of CsPbBr3 QDs. The highest PLQY is achieved in the 0.33Rb-2Eu heat-treated at 500 °C–6 h, reaching 54%. Furthermore, among the light-emitting diodes (LEDs) prepared with 1Cs-0Eu, 1Cs-2Eu, or 0.33Rb-2Eu, 0.33Rb-2Eu has the highest color gamut coverage (108.9% of the National Television Standards Committee color gamut and 92.7% of Rec. 2020 color gamut at 20 mA) and the strongest durable high-power driving capability, making it an ideal material for green LEDs.