Stable CsPbX3 (Br/Cl) Perovskite Nanocrystal Layer Passivated with Al-Doped CdSe for Blue Light-Emitting Diodes

Perovskite nanocrystals (PNCs) are ideal for optical devices due to their adjustable emission band and high photoluminescence. However, blue light-emitting perovskite nanocrystals (PNCs) exhibit poor performance compared to their green and red-emitting PNC counterparts. Herein, we introduce a simple strategy for increasing the stability of blue light-emitting CsPb (Br/Cl)3 PNCs passivated with an Al-doped CdSe layer. This simple strategy successfully achieves highly stable PNCs with photoluminescence (PL) emission ranging from 454 to 460 nm with a full width at half-maximum (FWHM) ranging from 18 to 22 nm; changes in bandgaps are also observed, and the corresponding PLQY values show a significant change after CdSe/Al modification. In addition, CsPb (Br/Cl)3 PNCs with a CdSe layer doped with Al formed on the surface show remarkable stability under ambient conditions, including thermal exposure, water resistance, and ultraviolet (UV) irradiation. A light-emitting diode (LED) device was constructed to demonstrate the feasibility of the approach by combining the optimal CsPb(Br/Cl)3/CdSe/Al PNCs with an existing commercial 365 nm UV chip, resulting in bright blue light emission with CIE color coordinates of (0.16, 0.09). All of the findings suggest that doped CsPb (Br/Cl)3/CdSe/Al PNCs have the potential to be used as color converters in liquid crystal displays (LCDs).