Simultaneous Enhancement of Photoluminescence and Stability of CsPbCl Perovskite Enabled by Titanium Ion Dopant.

The application of CsPbCl perovskite is limited by the low photoluminescence quantum yield (PLQY), weak luminescence, and unpromising stability. Doping impurity ions has been considered as an effective strategy to tune the optoelectronic performances of perovskite. In this work, heterovalent Ti ions are successfully doped into CsPbCl nanocrystals. It is found that Ti ion doping could effectively improve the photoluminescence (PL) performance of CsPbCl nanocrystals. Density functional theory (DFT) calculations reveal that Ti ions could introduce more band-edge states around the conduction band minimum of CsPbCl, which is conducive to release electrons into conduction band. Furthermore, Ti ion doping could inhibit the Cl vacancy concentration in CsPbCl and prevent the in-gap state caused by Cl vacancy. Notably, the stability of CsPbCl perovskite is greatly improved through Ti ion doping. This work provides a new perspective for improving the optoelectronic properties of all-inorganic perovskites through heterovalent metal ion doping.