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The CsPbBr3 perovskite materials have promising applications in various optoelectronic devices due to their advantages of high luminescence color purity, tunable band gap, and high photoluminescence quantum yield. Herein, the phase stability, electronic structure, and optical properties of CsPbBr3 under rare-earth (RE) doping and hydrostatic pressure have been studied using density functional theory calculations. The relationship between properties of perovskites and different RE doping and pressure was summarized. The band gap of CsPbBr3:RE appeared reduction with the decreasing radius of the doping RE ions, which can guide the adjustment of band gap. The pressure coefficients of undoped CsPbBr3 is − 0.016 eV/GPa, while that of RE-doped CsPbBr3 exhibits an average of − 0.0144 eV/GPa. The combination of RE doping and pressure provides a wider tunable range for band gap. The rare-earth doping and applying pressure are of great significance for the regulating properties of perovskites. Our work provided the opportunities to unveil the underlying mechanism of the doping effect and pressure engineering. [ABSTRACT FROM AUTHOR]

The two-dimensional (2D) transition metal thiophosphates family CdPS3 and CdPSe3 are supposed to explore pressure-relevant structural and electronic behaviors as support to build 2D spintronic devices. The pressure-induced phase transition and electronic properties of CdPX3 are investigated up to 40 GPa using first-principles calculation. CdPS3 undergoes reversible phase transitions at around 1.5 GPa and 25 GPa from C2/m structure to structure and then to P 3 ¯ 1 m structure, while the reversible phase transitions of CdPSe3 are found at approximately 13 GPa from R 3 ¯ structure to P 3 ¯ 1 m structure, reflected in the lattice constant mutation and cell volume collapse. The computed metallization transition is found at about 25 GPa and 13 GPa owing to energy band closure for CdPS3 and CdPSe3, respectively. As anisotropy increases with pressure, the enhanced metallic property is accompanied by the inter- and intra-layer sliding atom pairs induced by phase transition. The paper is conducive to considering the phase transition and metallization of CdPX3-type family under extreme conditions. [ABSTRACT FROM AUTHOR]