Organic polystyrene and inorganic silica double shell protected lead halide perovskite nanocrystals with high emission efficiency and superior stability

The practical application of all-inorganic semiconductor lead halide perovskite nanocrystals (LHP NCs) has been limited by their poor stability. Recently, a lot of research on core-shell structure has been done to improve the stability of perovskite NCs, but the effect was far from the application requirements. Herein, we, for the first time, report a convenient approach to synthesize organic-inorganic double shell CsPbBr3@SiO2@polystyrene (PS) NCs with an inter-core of CsPbBr3, the intermediate layer of SiO2 shell, and outmost PS shell. Particularly, the CsPbBr3@SiO2@PS NCs maintained more than 90% of their initial photoluminescence (PL) intensity under one month's ultraviolet lamp irradiation or in 85 degrees C and 85% relative humidity (RH) condition. The white-light-emitting-diodes (WLEDs) were fabricated by encapsulating commercial InGaN chip with CsPbBr3@SiO2@PS NCs and K2SiF6:Mn4+ (KSF:Mn4+) phosphor with a luminous efficacy of similar to 100 lm/W at 20 mA current and a color gamut of 128% of the National Television Standards Committee (NTSC) standard. In addition, these WLEDs still maintain 91% of the initial luminous efficacy after 1200 h of continuous lighting. These results demonstrated that double shell-protected CsPbBr3 perovskite NCs have great potential in the field of WLEDs.