Achieving efficiency above 30% with new inorganic cubic perovskites X 2 SnBr 6 (X = Cs, Rb, K, Na) via DFT and SCAPS-1D
Md. Ferdous Rahmana b✉, Tanvir Al Galiba b, Md. Azizur Rahmana b, Md. Hafizur Rahmana b, Md. Harun-Or-Rashida b, Md. Al Ijajul Islama b, Md. Monirul Islama b, N. Dhahric, Ahmad Irfand
- aAdvanced Energy Materials and Solar Cell Research Laboratory, Department of Electrical and Electronic Engineering, Begum Rokeya University, Rangpur 5400, Bangladesh
- bAdvanced Energy Materials and Solar Cell Research Laboratory, Department of Electrical and Electronic Engineering, Begum Rokeya University, Rangpur 5400, Bangladesh. ferdousapee@gmail.com
- cDepartment of Physics, College of Science, Northern Border University, Arar, Saudi Arabia
- dDepartment of Chemistry, College of Science, King Khalid University, P.O. Box 9004, Abha 61413, Saudi Arabia
- ✉Corresponding author
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Abstract
The solar sector is shifting towards lead-free, inorganic cubic halide perovskites due to their superior structural, electronic, and optoelectronic properties. This study uses density functional theory (DFT) to examine the structural, electronic, and optical properties of X2SnBr6 (X = Cs, Rb, K, Na) and assesses their photovoltaic performance through the Solar Cell Capacitance Simulator - One Dimensional (SCAPS-1D). The results show each material has a direct band gap at the Γ-point, low optical losses, and high absorption, making them promising for solar and optoelectronic applications. For Cs2SnBr6, Rb2SnBr6, K2SnBr6, and Na2SnBr6 absorbers with TiO2 electron transport layer (ETL), power conversion efficiencies (PCE) of 29.22%, 27.25%, 30.62%, and 29.51% were achieved, with open-circuit voltages (VOC) of 1.02, 0.87, 0.83, and 0.77 V, short-circuit currents (JSC) of 32.27, 36.72, 42.69, and 45.48 mA cm-2, and fill factors (FF) of 88.38, 85.18, 85.96, and 81.85%, respectively. Variations in X-cation size notably influence bandgap energy, band structure, and optoelectronic properties, impacting solar cell efficiency. This study supports the development of lead-free hybrid solar cells and other optoelectronic devices.