Moisture-Assisted Molecular Sieve-Confined Synthesis of Lead-Free CsAgCl2 Perovskite-Derivative Nanocrystals

Perovskite nanocrystals (NCs) have garnered extensive attention for their excellent photoelectric properties. However, the widespread use of and development of perovskite materials have been hindered by the significant toxicity associated with lead. The exploration of lead-free alternatives, such as silver-based perovskite-derivative NCs, faces difficulties in synthesizing NCs with an average diameter of less than 50 nm owing to their extremely high surface energy. To address these problems, we successfully synthesized lead-free CsAgCl2 perovskite-derivative NCs with an average diameter as small as 45.22 nm. This was achieved using molecular sieves (MS) as templates for confined space synthesis. Water vapor entered the pores of MS and underwent capillary condensation. The resulting liquid water facilitated the dissolution and diffusion of CsCl, which subsequently reacted with AgCl to produce CsAgCl2. The as-obtained CsAgCl2 NCs exhibited a photoluminescence quantum yield (PLQY) of 22 %, with an emission center at 610 nm and a full width at half maximum of 211 nm. These characteristics are indicative of a typical self-trapping exciton (STE) emission material displaying warm white light. When integrated into a white light-emitting diode (WLED), it achieves Commission Internationale de 'Eclairage (CIE) color coordinates of (0.3553,0.3408), a correlated color temperature (CCT) of 4556 K, and a maximum brightness of 316.55 cdm−2. This suggests a promising application prospect for single-component white light illumination.