Very Efficient Visible Light Energy Harvesting and Conversion by Spectral Sensitization of High Surface Area Polycrystalline Titanium Dioxide Films

Abstract

By using high surface area (roughness factor ca. 200) polycrystalline anatase films together with tris(2, 2'-bi-pyridyl-4, 4'-dicarboxylate)ruthenium(II), RuL34-, as a sensitizer, we have achieved unprecedentedly high visible light to electric current conversion efficiencies in regenerative photoelectrochemical cells. Incident photon to current conversion efficiencies of 73% have been obtained at the wavelength of maximum absorption of the dye in the presence of iodide as an electron donor. Bromide is oxidized under the same conditions with an efficiency of 56%. A regenerative cell based on the Br2/Br− redox system gives a monochromatic light to power conversion efficiency of 12% with a fill factor of 74%. Preliminary results with polychromatic illumination are also presented. © 1988, American Chemical Society. All rights reserved.