Four organic dyes (XS10–13) employing carbazole unit as electron donor and N,N-dimethylarylamine moieties as electron-donating groups were designed and synthesized for nanocrystalline TiO 2 dye-sensitized solar cells. The electron-donating groups of dimethylarylamine increase the electron density of donor moiety and enhance the molar extinction coefficient of dyes. For a typical device the maximum IPCE value could reach 86%, with a short-circuit photocurrent density (J sc ) of 9.8mAcm −2 , an open-circuit photovoltage (V oc ) of 642mV, and fill factor (FF) of 0.63, which corresponds to an overall conversion efficiency (η) of 4.0%. For a comparison, the N719-sensitized TiO 2 solar cell showed an efficiency of 6.4%.