Simultaneous Enhancement of Photoluminescence and Stability of CsPbCl₃ Perovskite Enabled by Titanium Ion Dopant

The application of CsPbCl₃ 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 Ti³⁺ ions are successfully doped into CsPbCl₃ nanocrystals. It is found that Ti³⁺ ion doping could effectively improve the photoluminescence (PL) performance of CsPbCl₃ nanocrystals. Density functional theory (DFT) calculations reveal that Ti³⁺ ions could introduce more band-edge states around the conduction band minimum of CsPbCl₃, which is conducive to release electrons into conduction band. Furthermore, Ti³⁺ ion doping could inhibit the Cl vacancy concentration in CsPbCl₃ and prevent the in-gap state caused by Cl vacancy. Notably, the stability of CsPbCl₃ perovskite is greatly improved through Ti³⁺ ion doping. This work provides a new perspective for improving the optoelectronic properties of all-inorganic perovskites through heterovalent metal ion doping.