“Surface Charge Transition Levels and Hole Localization of Dopants in BiVO4(010) Photoanodes” (2026), by Changkyu Cho et al. Energy research paper. Original abstract below, unchanged. A free PDF is available.

Surface Charge Transition Levels and Hole Localization of Dopants in BiVO4(010) Photoanodes

Changkyu Cho, Kyunhun Lee, Yonghyuk Lee et al. · October 23, 2026 · Energy

Abstract

Bismuth vanadate (BiVO4) is a benchmark oxide photoanode whose performance is governed by surface states, yet the thermodynamics and charge transition levels (CTLs) of its surface defects remain far less characterized than its bulk defect physics. Here we use dielectric-dependent hybrid density functional theory to compute formation energies and CTLs for oxygen vacancies and for substitutional n-type (Mo, W) and p-type (Ca, Sr) dopants on BiVO4(010). Under the O-rich conditions of anodic operation, Mo and W substitute on the V sublattice, which they prefer over the Bi site by 3.3 and 3.7 eV for a Fermi level at the conduction band edge. Surface oxygen vacancies are shallow donors whose ε(2+/0) level lies 0.16 eV below the conduction band and are ionized over almost the whole gap. MoV and WV are deeper donors at 0.51 and 0.58 eV below the conduction band. CaBi is a shallow acceptor 0.02 eV above the valence band, whereas SrBi has no transition within the gap and is ionized at every Fermi level. The two acceptors also place the hole differently, CaBi on the outermost oxygen layer and SrBi in the interior. Because photoanode operation is limited by holes reaching the surface, an acceptor that captures photogenerated holes on the outermost oxygen layer should be more useful for water oxidation than one that leaves them in the interior, which makes CaBi the more promising p-type dopant of the two.

Free PDF DOI: 10.21203/rs.3.rs-11239054/v1