“…The conduction band minimum (CBM) and valence band maximum (VBM) were found to be localized at the Γ point. Table shows the E g calculated with mBJ-GGA ranging from 1.983 eV for CsPbI 3 to 3.325 eV for CsPbCl 3 , while E g calculated with mBJ + SOC ranges from 1.066 eV for CsPbI 3 to 2.182 eV for CsPbCl 3 , which is consistent with previous theoretical predictions. ,,,,,− Because of its proper band gap of 1.983 eV, CsPbI 3 is suitable for light-absorber applications, whereas CsPbBr 3 and CsPbCl 3 with band gaps of 2.420 and 3.325 eV, respectively, show promising application prospects in solar cells, LEDs, lasers, and photodetectors . Because the E g values with SOC are small in comparison to the experimental results, the alloy formula was used to correct the E g determined by the mBJ-GGA + SOC method ,− where Δ E g (A 1– x B x ) is the change in band gap for the mixed CsPb(I 1– x Br x ) 3 and CsPb(Br 1– x Cl x ) 3 perovskites, Δ E g (A) is the change in band gap for pure CsPbI 3 /CsPbBr 3 , and Δ E g (B) is the change in band gap for pure CsPbBr 3 /CsPbCl 3 .…”