Pressure-induced band gap tuning in Cs2TiBr6: A theoretical study

In this study, we have explored the effect of hydrostatic pressure on the stability, mechanical, electronic and optical properties of Cs2TiBr6 for the first time. In the range of 0-15 GPa, Cs2TiBr6 is dynamically stable based on the calculations of phonon dispersion. Under pressure, Cs2TiBr6 is mechanically stable and it is a ductile material. The DFT + U method can provide an accurate band gap for Cs2TiBr6. The band gap of Cs2TiBr6 is reduced to the desired value at high pressure. The optical absorption ability is greatly enhanced under pressure. Our study shows that hydrostatic pressure is an effective approach to decrease the band gap of Cs2TiBr6 and increase the optical absorption in the whole visible light region, which can further improve the efficiency of this material.

Automated summary

In this study, the effect of hydrostatic pressure on Cs2TiBr6 was investigated for the first time, revealing that pressure can decrease the band gap value and enhance the optical absorption ability, ultimately improving the material efficiency.