Epitaxial growth of CsPbCl3@Cs2NaInCl6 core-shell nanocrystals with enhanced luminescence and stability

Metal halide perovskite (MHP) nanocrystals (NCs) exhibit outstanding optoelectronic properties, making them promising candidates for light-emitting diodes (LEDs). However, their practical application is severely hindered by poor environmental stability. Specifically, violet-emitting CsPbCl 3 NCs suffer from low luminescence properties because of deep-level trap-mediated non-radiative recombination. Here, we report a core-shell structure in which a CsPbCl 3 NC is epitaxially coated with a Cs 2 NaInCl 6 double perovskite shell via a hot-injection method. The resulting CsPbCl 3 @Cs 2 NaInCl 6 heterostructures feature type-I band alignment, enabling effective surface defect passivation and strong charge carrier confinement within the CsPbCl 3 core. As a result, the photoluminescence quantum yield (PLQY) of CsPbCl 3 NCs increases dramatically from 4.4% to 49.5%, accompanied by a prolonged photoluminescence lifetime and a narrower emission spectral full width at half maximum (FWHM). Beyond luminescence enhancement, the Cs 2 NaInCl 6 shell imparts remarkable resistance against damage from water, UV irradiation, and heat. Furthermore, the same encapsulation strategy significantly improves the stability of Mn and Ni-doped CsPbCl 3 (CsPbCl 3 :Mn and CsPbCl 3 :Ni) NCs. This work provides an effective strategy to simultaneously enhance luminescence performance and environmental stability of CsPbCl 3 NCs through passivation with a double perovskite shell.