Ultrastable and highly efficient green-emitting perovskite quantum dot composites for Mini-LED displays or backlights

Although tremendous efforts have been made to enhance the stability of lead halide perovskite quantum dots (PeQDs), they cannot meet the long-term requirements of photoelectric devices due to their poor reliability when attacked by multiple factors. Herein, we report ultrastable CsPbBr3:Sr/PbBr(OH)/molecular sieve composites with a high photoluminescence quantum yield of 75% and high overall stability when exposed to water, blue light and heat, owing to (i) the increased formation energy of CsPbBr3 PeQDs by Sr doping and (ii) good encapsulation by PbBr(OH) and molecular sieves. These composites maintain 54% of their initial intensity after being aged at 85 °C and 150 mW cm−2 for 720 min, which is superior to commercial green CdSe-based QDs. These promising composites are then used to produce Mini-LED backlights with a high luminous efficacy of 86 lm/W and a color area of ~124% of the National Television Standards Committee or 93% of the Rec. 2020 standards by combining them with red CdSe/CdS/ZnS QDs and a blue Mini-LED chip. We believe that highly reliable PeQDs can be achieved by building well-designed composite structures, thus enabling them to be practically applied in emerging lighting and displays.