Band Edge Electronic Structure of BiVO₄: Elucidating the Role of the Bi s and V d Orbitals

Abstract

We report the first-principles electronic structure of BiVO 4, a promising photocatalyst for hydrogen generation. BiVO 4 is found to be a direct band gap semiconductor, despite having band extrema away from the Brillouin zone center. Coupling between Bi 6s and O 2p forces an upward dispersion of the valence band at the zone boundary; however, a direct gap is maintained via coupling between V 3d, O 2p, and Bi 6p, which lowers the conduction band minimum. These interactions result in symmetric hole and electron masses. Implications for the design of ambipolar metal oxides are discussed. © 2009 American Chemical Society

Insights from Crystal Size and Band Gap on the Catalytic Activity of Monoclinic BiVO4

“…So, there is more distortion of lone pairs in powder samples calcined at 700 o C rather than the samples calcined at 350 o C. This is an effect that is canceled when we characterize the sample with XRD as it is not sensitive enough to the slight changes in the bond lengths that have an inverse effect. The band structure in scheelite-monoclinic BiVO 4 is formed by the Bi 6s, O2p and V3d orbitals; among them, valence band is formed by the hybrid of Bi6s and O2p and conduction band by V3d [25]. There is a distinct variation observed in the electronic structure of the samples when the distortion of the VO 4 3-tetrahedron occurs.…”

The electronic structure of the antimony chalcogenide series: Prospects for optoelectronic applications

“…The extent of mixing between the metal s and anion p states creates a dispersed valence band with the VBM raised through the anti-bonding nature of the interactions. This can reduce the band gap and has become an important concept in band gap engineering and is used to design devices with tailored band gaps for optoelectronic applications [72,73,74,75]. Additionally, the valence band mixing of metal s with anion p states suggests that materials with lone pairs on the cations may be good candidates for p-type conducting materials [76,77,78,79].…”

Doping properties of monoclinic BiVO4studied by first-principles density-functional theory

“…Therefore, searching for metal oxide semiconductors with appropriate bandgaps has been one of the research focuses in the field of PEC water splitting [2][3][4][5][6][7][8]. Among the large number of metal oxides proposed, BiVO 4 has shown very promising performance [9][10][11][12]. The monoclinic BiVO 4 has a direct bandgap of 2.4-2.5 eV, good optical absorption properties, and reasonable band edge alignment with respect to H/H 2 O and O/H 2 O redox potentials [12,13].…”