Computational and Experimental Study on Electronic Band Structure of Bismuth Ferrite: A Promising Visible Light Photocatalyst

Electronic band structure of bismuth ferrite (BFO) is studied by computational and experimental methods. Bandgap of BFO is precisely determined using optical absorption spectra as well as density functional calculation (DFT). Both methods give a comparable result that BFO can have both of direct or indirect (very close to direct) bandgap of about 2.0~2.2 eV. Furthermore, electronic transition in BFO occurs via the unoccupied O 2p to the occupied Fe 3d states or the d-d transition in Fe 3d states. Intriguing electronic structure of BFO, a narrow bandgap and a multiple electronic transition route, render it as a promising candidate for a visible light photocatalyst.