Revealing the influence of B-site doping on the physical properties of CsPbI3: A DFT investigation

The effects of different B-site cation doping with the low concentration on the structural, electronic, and optical properties of CsPbI3 have been revealed from density functional theory calculations. The change in the structural parameters for CsPb0.875B0.125I3 can be explained from the bond length (B-I). Most metal doping is not conducive to the improvement of stability in CsPbI3. The transition from direct to indirect band gap is found for CsPb0.875B0.125I3 (B = Mg, Zn, Cd, and Hg), while the nature of the direct band gap is still observed for CsPb0.875B0.125I3 (B = Ca, Sr, Ge, and Sn). The increased stability and narrow band gap can be achieved by doping Ge and Sn. The optical absorption coefficient of CsPb0.875B0.125I3 (B = Ge and Sn) is slightly stronger than that of CsPbI3. The results show that it is the most promising strategy to increase the stability and possess the desirable band gap with the help of Ge and Sn doping.