Precise Hue Control in a Single-Component White-Light Emitting Perovskite Cs 2 SnCl 6 through Defect Engineering Based on La 3+ 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 Cs 2 SnCl 6 :La 3+ microcrystal (MC). The dual emission bands centered at 450 and 560 nm are attributed to the intrinsic STE1 emission in host lattice Cs 2 SnCl 6 and the STE2 emission induced by the heterovalent La 3+ 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 Sn 4+ /Cs + ratios in starting materials. The effects of the doping heterovalent La 3+ ions on the electronic structure and photophysical properties of the Cs 2 SnCl 6 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.