Computational study of iron perovskite CH3NH3FeI3as an alternative to the lead perovskite CH3NH3PbI3for application in solar cells

Abstract

Structural and optical properties of methylammonium iron iodide perovskite CH3NH3FeI3 are studied at DFT-PBE(mBJ)/FP-LAPW + lo level of theory to assess feasibility of the replacement of the toxic lead with the non-toxic iron in the perovskite layer of solar cells. Starting from experimental crystal structure of the Pb perovskite, volume and aspect ratio (c/a) and atomic positions are optimized for the CH3NH3FeI3 structure, and its electronic and optical characteristics are calculated. An index, measuring the raw optical performance of the light harvesting layer of a solar cell is introduced and calculated for the two Fe and Pb perovskites. Comparative values of this index shows that the iron perovskite CH3NH3FeI3 has an acceptable optical performance, ∼61% that of the Pb perovskite CH3NH3PbI3. Analysis of the Brewster angles (θ B) calculated for the TiO2/perovskite and perovskite/spiro interfaces shows that the Fe perovskite solar cell can have better optical harvesting performance by a factor of 1.32, which improves its comparative overall performance up to 80%. As a conclusion, application of iron perovskite CH3NH3FeI3 is promising, especially due to its much lower costs and significantly alleviated environmental hazards of the incorporating solar cells. © 2020 IOP Publishing Ltd.