A DFT study of the stability and optoelectronic properties of all-inorganic lead-free halide perovskites. (February 2022)

• Record Type: Journal Article
• Authors: Liu, Diwen; Peng, Huan; Li, Qiaohong; Sa, Rongjian
• Is Part Of: Journal of physics and chemistry of solids. Volume 161(2022)
• Publication Date: 2022-02
• Subjects: All-inorganic perovskite -- Stability -- Band gap -- Optical absorption -- DFT; Solids -- Periodicals; Solides -- Périodiques; Solids; Periodicals; 530.41
• DOI: 10.1016/j.jpcs.2021.110413
• Languages: English
• ISSNs: 0022-3697

Abstract

Abstract: In recent years, all-inorganic lead-free CsGe0.5 Sn0.5 I3 has been proposed as a promising candidate for perovskite solar cells. In the present study, the stability and optoelectronic properties of the CsGeX3 and Cs2 GeX6 (X = Cl, Br, I) compounds and mixed CsGe1- x Sn x I3 perovskites have been explored using first-principles calculations. The results indicate that the CsGeX3 compounds and Cs2 GeCl6 are stable at room temperature, while Cs2 GeBr6 and Cs2 GeI6 are unstable. A phase transition is revealed for the CsGe1- x Sn x I3 systems when the ratio of Sn doping is over 0.53. In addition, both CsGe2/3 Sn1/3 I3 and CsGe0.25 Sn0.75 I3 show the potential tendency for phase segregation. CsGe2/3 Sn1/3 I3 and CsGe0.25 Sn0.75 I3 have suitable band gaps and exhibit strong absorption coefficients, which are the promising candidates for solar cells. Our work demonstrates the favorable optoelectronic properties of novel lead-free mixed Ge–Sn perovskites for single-junction solar cells. Graphical abstract: Image 1 Highlights: The stability and optoelectronic properties of all-inorganic lead-free halide perovskites are systematically studied. A phase transition is observed for the CsGe1- x Sn x I3 systems. CsGe2/3 Sn1/3 I3 and CsGe0.25 Sn0.75 I3 are the promising candidates for solar cells.