Engineering the Bandgap and Surface Structure of CsPbCl3 Nanocrystals to Achieve Efficient Ultraviolet Luminescence

All-inorganic halide perovskites have attracted wide attention due to their intriguing luminescent properties including efficient light conversion, narrow emission bandwidth and composition-dependent emissions. However, their emissions mainly locate in the visible region and they often suffer from low luminescent efficiency in the blue and violet region. Herein, we report the design of novel ultraviolet luminescent CsPbCl 3 nanocrystals (NCs) with the emission peak at 381 nm through doping of cadmium ions. Subsequently, a surface passivation strategy with CdCl 2 is adopted to improve their photoluminescence quantum yield (PLQY) with the maximum value of 60.5%, which is 67 times higher than that of the pristine counterparts. The PLQY of the surface passivated NCs remains over 50% after one week while the pristine NCs show negligible emission. By virtue of density functional theory calculations, we reveal that the higher PLQY and better stability after surface passivation may result from the significant elimination of surface chloride vacancy (V Cl ) defects. These findings provide fundamental insights into the optical manipulation of metal ions-doped CsPbCl 3 NCs, thus laying a foundation for the future design of efficient UV-emitting halide perovskites through bandgap and surface structure engineering.