Precise Hue Control in a Single‐Component White‐Light Emitting Perovskite Cs2SnCl6 through Defect Engineering Based on La3+ Doping

Single-component white light emitters based on the all-inorganic perovskites will act as outstanding candidates for applications in solid-state lighting thanks to their abundant energy states for self-trapped excitons (STE) with ultra-high photoluminescence (PL) efficiency. Here, a complementary white light is realized by dual STEs emissions with blue and yellow colors in a single-component perovskite Cs2 SnCl6 :La3+ microcrystal (MC). The dual emission bands centered at 450 and 560 nm are attributed to the intrinsic STE1 emission in host lattice Cs2 SnCl6 and the STE2 emission induced by the heterovalent La3+ doping, respectively. The hue of the white light can be tunable through energy transfer between the two STEs, the variation of excitation wavelength, and the Sn4+ /Cs+ ratios in starting materials. The effects of the doping heterovalent La3+ ions on the electronic structure and photophysical properties of the Cs2 SnCl6 crystals and the created impurity point defect states are investigated by the chemical potentials calculated using density functional theory (DFT) and confirmed by the experimental results. These results provide a facile approach to gaining novel single-component white light emitter and offer fundamental insights into the defect chemistry in the heterovalent ions doped perovskite luminescent crystals.