Influences of Hydrostatic Pressure on the Photoelectric Properties of Cubic Phase CsPbBr3 Materials Based on First Principles

In view of the incomplete coverage of the photoelectric properties of the cubic phase CsPbBr3 material under the same model, the influences of hydrostatic pressure on the structure and photoelectric properties of the material are studied in depth based on first principles. The results show that when the hydrostatic pressure increases from 0 to 7 GPa, the band gap of CsPbBr3 decreases from 1. 80 eV to 0. 74 eV, and the bond length of Cs-Br and Pb-Br decreases by 0. 31 angstrom and 0. 22 angstrom, respectively, which indicate that the coupling effect between atoms increases. The static permittivity, static refractive index and static reflectivity of CsPbBr3 increase by 10. 3%, 5. 0% and 12. 0% under 7 GPa pressure, respectively. The transition degree and migration rate of electrons increase. When CsPbBr3 falls into the low-energy region, the pressure can reduce the edge energy of the imaginary part of the dielectric function, extinction coefficient, absorption coefficient, conductivity and loss function from 0. 94 eV to 0. 69 eV, the conductivity increases by 17. 7% and the extinction coefficient averagely increases by 11. 5%. The pressure increases the loss function by 20. 6% on average when CsPbBr3 falls into the high-energy region. In addition, the pressures in the UV-Vis and near-infrared regions can increase the absorption coefficients of CsPbBr3 to 1. 1 and 4. 7 times of the original value, respectively, and therefore can strengthen the absorption capacity of light. These properties can expand the application of the material.