Dye sensitised zinc oxide: aqueous electrolyte: platinum photocell

Abstract

TITANIUM oxide photocells, which are photochemically stable and decompose water into hydrogen and oxygen^1,2, have a low efficiency³ and their spectral response is mostly in the ultraviolet, where the Sun's output is low. Other semiconductors such as cadmium sulphide or gallium phosphide, having smaller band gaps, are destroyed by light and their photocurrents deteriorate rather rapidly⁴. Photocurrents in dye sensitised photocells composed of aqueous electrolyte solutions and various semiconductor electrodes have also been studied^5–7. All results obtained so far show that the dye sensitised photo-currents are very small, ∼ 10⁻⁶–10⁻⁹ A cm⁻², corresponding to a quantum efficiency ≲ 10⁻². In this paper we report the successful construction of cells with a high power efficiency.