Triruthenium carbonyl clusters {[Ru-3(Br)(CO)(11)](-) (denoted as Ru-1), [Ru-3(mu(2)-Br)(CO)(10)](-) (denoted as Ru-2), and [Ru-3(mu(3)-NPh)(Br)(CO)(9)](-) (denoted as Ru-3)} were synthesized on di(3-aminopropyl)viologen (DAPV)/indium tin oxide (ITO) using a surface reaction in a ruthenium (III) carbonyl [Ru-3(CO)(12)] solution, and were applied to photoelectrochemical cells (PECs) at the molecular level. The formation of DAPV on ITO was realized in the form of self-assembled monolayers. Ru-3(CO)(12) then easily reacted with the Br- of DAPV, and a mixture of Ru-1 and Ru-2 was formed on DAPV/ITO. Furthermore, Ru-3 was successfully anchored on DAPV/ITO by adding nitrosobenzene in order to react with Ru-2 on DAPV/ITO. The photocurrents of (Ru-1 and Ru-2)/DAPV/ITO and Ru-3/DAPV/ITO in PECs at the molecular level were 6.3 nA cm(-2) and 8.6 nA cm(-2), respectively. The quantum yield of Ru-3/DAPV/ITO was similar to 0.8%. Time-resolved photoluminescence spectroscopy and emission spectroscopy were recorded to bring out the photoinduced charge transfer process from ruthenium clusters to DAPV. (C) 2011 Elsevier B.V. All rights reserved.