Tuning electronic and optical properties of CsPbI3 by applying strain: A first-principles theoretical study

In this study, the effect of hydrostatic strain on the structural, electronic and optical properties of CsPbI3 was investigated by using first-principles calculations. The calculated results show that the band gap of CsPbI3 can be tuned from 1.03 to 2.14 eV when the strain ranges from - 5% to 5%. A suitable band gap (1.34 eV) of CsPbI3 can be obtained under a strain of -3% (1.40 GPa). The calculated elastic constants further imply that this compound is stable under the abovementioned condition. Moreover, bandgap narrowing leads to the stronger optical absorption in the visible light region.