A naturally available compound, ascorbic acid, was used as a sensitizer in a solid-state cell based on TiO2 and CuI. Photo-excited ascorbic acid molecules inject electrons into the conduction band of TiO2 and holes into the valance band of CuI, thus leading to photovoltage and photocurrent. The maximum photocurrent of 1.0 mA cm(-2) and photovoltage of 100 mV were observed for the solid-state TiO2/ascorbic acid/CuI cell with an effective area of 0.25 cm(2) under AM 1.5 conditions. (C) 2003 Elsevier B.V. All rights reserved.