Titania-based solar cells were fabricated by the use of a pheophytin derivative and a pheophytin-carotenoid adduct. The addition of the carotenoid moiety increased the photocurrent (J(sc) = 3.7 -> 6.0 mA cm(-2)), reduced the photovoltage (V-oc = 0.53 -> 0.46 V), and enhanced the solar energy-to-electricity conversion efficiency (eta = 1.4 -> 1.8%). The increase in photocurrent was explained in terms of electron and singlet-energy transfer from the carotenoid to the chlorin moiety as well as the prevention of the chlorin aggregate by the bulky carotenoid moiety and the resultant suppression of the singlet-triplet annihilation reaction. (c) 2007 Elsevier B.V. All rights reserved.