A density functional study of electronic and optical properties of perovskite (CH3CH2NH3PbI3) for photovoltaic cell application

In this study, we have performed ab-initio screening of the ethylammonium cation-based hybrid perovskite ethylammonium lead iodide (CH3CH2NH3PbI3or EPI) as the prospective absorber material for fabricating cost-effective and energy-efficient photovoltaic devices. The extensively studied methylammonium lead iodide (CH3NH3PbI3 or MPI) exhibits high efficiency but has serious environmental and stability related concerns due to leakage of lead. Therefore, we intend to replace (CH3NH3+or M+) cation in MPI with (CH3CH2NH3+or E+) and expect that so formed perovskite EPI would prove to be an eco-friendlier and more stable photovoltaic absorber material. In this investigation, we have employed FP-LAPW+lo method under density functional theory as provided in WIEN2k simulation code. We have employed a more accurate Tb-mBJ exchange correlation potential to calculate physical properties like energy bandgap, density of states, optical parameters and SLME relevant to photovoltaic applications. According to the findings of this study, EPI is direct bandgap material with bandgap of 2.17 eV at k-point R with optical absorption coefficient higher than 104 cm−1, which endorses it as a suitable photovoltaic absorber material. The dependence of optical coefficients on angular frequency of incident electromagnetic radiation has also been discussed. The theoretical power conversion efficiency comes out to be 18.9%.