Photoelectrochemical properties of metal-cluster oxide compounds, A₂Mo₃O₈ and (LiY)Mo₃O₈

PEC studies on the single crystals of the metal-cluster oxide compounds. A₂Mo₃O₈ (A = Zn, Mg, Fe), and polycrystalline LiYMo₃O₈ are reported. The photoresponse behaviour is attributed to the Mo d-d transition. The photopotential, the photocurrent vs applied voltage and the wavelength data indicate that n-Zn₂Mo₃O₈ is stable and possesses a small and indirect band gap of 1·55 eV and a direct band gap of 1·9 eV. With change in A ions in A₂Mo₃O₈, there is no significant change in the PEC properties. LiYMo₃O₈ is found to be of p-type. PEC studies show that excepting for poor electronic conductivity, A₂Mo₃O₈ possesses all the requisitie characteristics of an ideal photoanode for PAE of water for trapping solar energy.