Improvement of dye-sensitized solar cell performances through introducing europium dye with multiple excitation: dual enhancement in light absorption
Two Eu dyes, EuC28H19O9 and Eu2C28H23NO15 (named as Eu1 and Eu2) with multiple excitation, were used to co-sensitize a TiO2 photoanode with N719. Eu1 and Eu2 filled the absorption blank of N719 in the ultraviolet region and enhanced the absorption intensity of N719 in the visible region by multiple excitation. The performances of the dye-sensitized solar cell were improved by this dual enhancement in light absorption. The optical property, charge-transfer property, and electrochemical and photovoltaic properties of Eu1 and Eu2 were investigated by UV-visible spectroscopy, transient surface photovoltage measurement, cyclic voltammetry, and photocurrent–photovoltage measurement. The combination of Eu dye and N719 in DSSCs increased electron excitation, broadened the absorption spectrum and decreased charge recombination. The co-sensitized device showed an enhanced photocurrent (17.37 mA cm−2) and conversion efficiency (8.3%).