Effect of Pb-site doping on the structure, electronic and mechanical properties of CsPbI3 perovskite: A first-principles study

CsPbI3 3 has received a great deal of attention as the light-harvesting component of pure inorganic perovskite solar cells (PSCs). It is revealed that Pb-site doping is an effective way to enhance the electrical and optical properties of CsPbI3 3 compared with other methods. In this study, within the framework of the density functional theory (DFT), first-principles method was used to investigate different Pb-site ionic doping effect on the structural, mechanical, electrical, and optical properties of CsPbI3. 3 . We considered totally 11 doping elements, each with a doping concentration of 12.5 % (denoted as CsPb 0.875 M 0.125 I 3 , M is the doping element). The results revealed that all the doping systems are structurally stable with decreased bandgap values compared with the pristine CsPbI3. 3 . CsPb 0.875 M 0.125 I 3 (M=Ge, =Ge, Sn) exhibits similar behavior to CsPbI3, 3 , while CsPb 0.875 M 0.125 I 3 (M= = As, Sb, Bi) series present electron-doping character and CsPb 0.875 M 0.125 I 3 (M=Ga, =Ga, In, Tl) shows hole-doping effect. Mechanically, all the other elements mono-doped CsPbI3 3 satisfy the stability requirement except CsPb 0.875 Ga 0.125 I 3 . Moreover, most of doping systems show enhanced the absorption strength in the visible light region. By synthetically considering the mechanical, electronic and optical properties, it is suggested that CsPb 0.875 M 0.125 I 3 (M=Sb, =Sb, Fe) exhibit relatively superior characteristics compared with pristine and other elements mono-doped CsPbI3. 3 . Results obtained in the present work may provide valuable guidance for the synthesis and the performance refinement of all-inorganic CsPbI3-based 3-based PSCs in the future.