Exploring new lead-free halide perovskites RbSnM3 (M = I, Br, Cl) and achieving power conversion efficiency > 32

• Published in: The Journal of physics and chemistry of solids 2025-02, Vol.197, p.112437, Article 112437
• Main Authors: Harun-Or-Rashid, Md, Rahman, Md. Ferdous, Amami, Mongi, Ben Farhat, Lamia, Islam, Md. Monirul, Benami, Abdellah
• Format: Article
• Language: English
• Subjects: FP-DFT; Optoelectronic device; Perovskite; Photovoltaic cell; SCAPS-1D
• ISSN: 0022-3697
• DOI: 10.1016/j.jpcs.2024.112437

Lead-free ABX3 inorganic perovskites, where A = Cs, Rb; BSn, Ge; and X = I, Br, Cl, have recently gained significant attention due to their remarkable optical, structural, and electronic properties, as well as their potential for solar cell applications. In this study, we thoroughly examined the optical, structural, and electronic properties of RbSnM3 (M = I, Br, Cl) perovskites through first-principles calculations and explored their application in a HTL-free solar cell structure using SCAPS-1D. Our analysis revealed that RbSnI3, RbSnBr3, and RbSnCl3 have direct band gaps of 0.828, 0.988, and 1.242 eV, respectively, using the HSE functional. The electron charge distribution indicates a strong ionic bond between Rb and the halides, as well as a significant covalent bond between Sn and the halides. Additionally, we calculated optical properties such as electron loss function, absorption coefficients, and the real and imaginary parts of the dielectric functions. We also explored the photovoltaic performance of RbSnM3 absorbers paired with a SnS2 ETL layer, investigating different thicknesses, defect densities, doping concentrations, and interface defect densities. The highest power conversion efficiencies (PCE) achieved were 26.38 %, 29.79 %, and 32.53 % for RbSnI3, RbSnBr3, and RbSnCl3 absorber layers, respectively, when paired with a SnS2 ETL. Overall, RbSnCl3 stands out as a highly promising absorber material for future photovoltaic devices, especially when combined with the SnS2 ETL layer. •The optical, structural, electronic, and solar cell performances of RbSnM3 perovskites have investigated via DFT and SCAPS-1D•The analysis revealed that RbSnI3, RbSnBr3, and RbSnCl3 have direct band gaps of 0.828, 0.988, and 1.242 eV, respectively.•The electron charge distribution indicates a strong ionic bond between Rb and the halides.•The highest PCE achieved were 32.53 % RbSnCl3 absorber layers, when paired with a SnS2 ETL.