Insight into the role of (Y, Co) mono and codoping in BiFeO3: A comprehensive first-principles study on structural stability and photocatalytic activity

The present study investigates the effects of yttrium (Y) and cobalt (Co) mono and codoping in BiFeO₃(BFO), with an emphasis on how these dopants affect structural properties, magnetic characteristics, ferroelectric properties, and the electronic structure of BFO using first-principles calculation based on DFT (GGA + U) approximation. The study revealing the stability of dopants has been carried out using formation energy calculations with different possible charge states. Analysing the electronic structure and optical spectra, it is observed that cobalt (Co) doping and (Y, Co) codoping reduce the bandgap significantly, allowing enhanced visible light absorption for water oxidation. Also, from the band alignment studies, it can be inferred that the downward shift in the conduction band minimum on doping in BFO downgrades its ability to produce H₂ from water splitting. The electron localization function and charge density difference plots are evaluated to gain an insight into the chemical environment in pure and (Y, Co) doped BFO.