High-efficiency Ca2+ doping all-inorganic nanocrystals (CsPbBr3 and CsPbBr1I2) encapsulated in a superhydrophobic aerogel inorganic matrix for white light-emitting diodes

Abstract

All-inorganic halide perovskite nanocrystals (NCs) have become the most promising next generation luminescent materials due to their excellent properties. However, there are many nonradiative recombination defects in colloidal perovskite NCs, which reduce their luminescent efficiency and stability. In this work, we incorporated the alkaline-earth (AE) metal ion Ca2+ into NCs to further improve the photoluminescence quantum yield (PLQY) of CsPbBr3 and CsPbBr1I2 NCs. The PLQY of green-emitting CsPbBr3 and red-emitting CsPbBr1I2 NCs can be boosted to 72.3% and 78.7%, respectively by doping the optimum amount of Ca2+. At the same time, we adopted a simple and low-cost one-pot method to integrate Ca2+-CsPbX3 (X3 = Br3, Br1I2) NCs and superhydrophobic silica aerogels (AG), not only retaining the high PLQY of NCs, but also greatly improving the water, heat and light stability. Finally, the green-emitting Ca2+-CsPbBr3@AG, red-emitting Ca2+-CsPbBr1I2@AG composites and the blue chip as the light sources show a wide color gamut that accounts for 129% of the NTCS 1953 value and nearly 100% of the Rec.2020 value. Additionally, we fabricated white light-emitting diode (WLED) devices by coupling Ca2+-CsPbBr1I2@AG composites with commercial YAG:Ce3+ phosphors on blue chips, obtaining bright white light with a color rendering index (CRI) up to 92.2.