First principles study of structural, electronic and optical properties of Cs-doped CH3NH3PbI3 for photovoltaic applications

• Published in: Vacuum Vol. 160; pp. 440 - 444
• Main Authors: Taya, Ankur, Rani, Priti, Thakur, Jyoti, Kashyap, Manish K.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.02.2019
• Subjects: 71.15.Dx; 71.15.Mb; 84.60.Jt; DFT; PACS; Pseudopotential; Solar cells; Solar cells; DFT; PACS; Pseudopotential; 71.15.Dx; 71.15.Mb; 84.60.Jt
• ISSN: 0042-207X; 1879-2715
• DOI: 10.1016/j.vacuum.2018.12.008

Hybrid halide perovskites (HHPs) based solar cells have revolutionized the photovoltaic landscape by demonstrating the power conversion efficiencies (PCE) exceeding 23% at a low cost. Through first-principles pseudopotential calculations, we have investigated the structural, electronic and optical properties of Pb-based HHP, CH3NH3PbI3 (MAPbI3) and analyzed the effect of incorporating inorganic Cs+ at methyl ammonium (MA+) cation site in MAPbI3. Our results reveal that 12.5% of Cs-doping slightly enhances the absorption coefficient of MAPbI3, making it a promising candidate for highly efficient perovskite solar cells. This optical absorption is decided by the trade-off between widening of the band gap and increase of DOS in sub-VBM region on Cs-doping. Further, the compositional degradation of MAPbI3 can be prevented with this doping and the solar cells based on it can be used for the longer time. •Reduced H-bonding due to Cs-doping in MAPbI3 increases the structural stability.•Direct bandgap (1.62 eV) of Cs:MAPbI3 is suitable for visible light absorption in solar cells.•Cs-doing avoids the compositional degradation of MAPbI3 at no cost of optical absorption.