Core-shell-type nanoparticles with TiO2 cores and CaCO3 shells were applied as the electrode of dye-sensitized solar cells. The performance of the cell was significantly improved (as high as 26.7%) compared to the case when un-coated TiO2 particle film was used as electrode. The improved energy conversion efficiency has been ascribed to (i) enhanced dye adsorption due to the high isoelectric point of the overlayer, and (ii) the prevention of the back electron transfer by the insulating nature of the overlayer. (c) 2006 Elsevier B.V. All rights reserved.