Optical and photoelectrochemical characterization of pulsed laser deposited Bi4V2O11, BICUVOX, and BIZNVOX

Thin layers of three compounds from the BIMEVOX family (Bi4V2O11, Bi2V0.9Cu0.1O5.35, and Bi2V0.9Zn0.1O5.35) were prepared via pulsed laser deposition technique on quartz, silicon, and platinum foil and tested as photoanodes for water photooxidation. The film formation, as well as the crystallization upon heating, was characterized using X-ray diffraction and Raman spectroscopy. The optical properties were investigated using spectroscopic ellipsometry allowing the determination of the complex dielectric function, the absorption coefficients, the direct band gaps (3.2-3.4 eV), as well as weak, indirect transitions in the visible range (2.4-2.5 eV) for all tested BIMEVOX thin (67-81 nm) layers. Finally, the photoelectrochemical activity of all compounds was tested. Among the thin BIMEVOX layers, the highest photocurrent (7.4 μAcm− 2) was generated by a Pt/Bi4V2O11 photoanode. Samples doped by Cu and Zn exhibited up to 40 (BICUVOX) and 14 (BIZNVOX) times lower photocurrents. Thus, the presence of Zn and Cu atoms in the structure did not enhance the photoactivity of doped Bi4V2O11.