Stabilization of Lead-Reduced Metal Halide Perovskite Nanocrystalsby High-Entropy Alloying

Colloidal metal halide perovskite (MHP) nanocrystals (NCs) arean emerging class offluorescent quantum dots (QDs) for next-generationoptoelectronics. A great hurdle hindering practical applications, however, is theirhigh lead content, where most attempts addressing the challenge in the literaturecompromised the material's optical performance or colloidal stability. Here, wepresent a postsynthetic approach that stabilizes the lead-reduced MHP NCsthrough high-entropy alloying. Upon doping the NCs with multiple elements inconsiderably high concentrations, the resulting high-entropy perovskite (HEP)NCs remain to possess excellent colloidal stability and narrowband emission, witheven higher photoluminescence (PL) quantum yields,eta PL, and shorterfluorescence lifetimes,Tau PL. The formation of multiple phases containing mixedinterstitial and doping phases is suggested by X-ray crystallography. Importantly, the crystalline phases with higher degrees of latticeexpansion and lattice contraction can be stabilized upon high-entropy alloying. We show that the lead content can be approximatelyreduced by up to 55% upon high-entropy alloying. Thefindings reported here make one big step closer to the commercialization ofperovskite NCs