Y2O3:Er3+ nanorods are synthesized by means of a hydrothermal method and then introduced into a TiO2 electrode in a dye-sensitized solar cell (DSSC). Y2O3:Er3+ improves infrared light harvest via up-conversion luminescence and increases the photocurrent of the DSSC. The rare earth ions improve the energy level of the TiO2 electrode through a doping effect and thus increase the photovoltage. The light scattering is ameliorated by the one-dimensional nanorod structure. The DSSC containing Y2O3:Er3+ (5 wt %) in the doping layer achieves a light-to-electric energy conversion efficiency of 7.0 %, which is an increase of 19.9 % compared to the DSSC lacking of Y2O3:Er3+.