Improvement of the performance of dye-sensitized solar cells with TiO_2 photoanodes in unsaturated

摘要

The photoelectrochemical properties of the TiO_2 photoanode in unsaturated dye-adsorption state for dye-sensitized solar cells (DSCs) were investigated by the electrochemical impedance spectroscopy (EIS) and the light absorption spectrum. Significant low charge recombination as well as light absorption saturation was observed with the TiO_2 photoanode in unsaturated dye-adsorption state. Due to these effects, from saturated to unsaturated dye-adsorption state, the fill factor (ff) increased from 0.60 to 0.78 and the open circuit photovoltage (V_(oc)) increased from 770 mV to 780 mV. The short circuit photocurrency density (I_(sc)) reached the maximum 10.51 mA cm-2 before the TiO_2 photoanode attained the saturated dye-adsorption state. The energy conversion efficiency (η) of DSC was enhanced from 4.86% to 5.34% by adjusting the TiO_2 photoanode from saturated to unsaturated dye-adsorption state.