CdSe quantum dots (QDs) are adsorbed onto nanostructured SnO2 and planar FTO electrodes by a chemical adsorption technique. Optical absorption and the incident-photon-to-current conversion efficiency (IPCE) are studied by using photoacoustic and photoelectrochemical methods. The growth rate of the CdSe QDs depends on the morphology of the substrate. Larger IPCE peak values and larger integrated area for the IPCE spectra are obtained for the nanostructured SnO2 electrodes. The ultrafast carrier dynamics of the CdSe QDs are studied using a transient grating technique. It is found that the electron relaxation of the CdSe QDs depends strongly on the morphology of the substrate. (C) 2007 Elsevier B.V. All rights reserved.