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 °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 ~ 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.