Photoelectrochemical properties of metal-cluster oxide compounds, A<inf>2</inf>Mo<inf>3</inf>O<inf>8</inf> and (LiY)Mo<inf>3</inf>O<inf>8</inf>

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. © 1988 the Indian Academy of Sciences.