Enhance the performances of dye-sensitized solar cell by a new type of sensitizer to co-sensitize zinc oxide photoelectrode with ruthenium complex

We designed a new type of sensitizer for dye-sensitized solar cells based on ZnO photoelectrode. Three five-coordinate transition metal complexes [2,6-(ArNCMe)2C5H3NMCl2·nCH3CN] (MZn, Cd, Hg) (named as Zn1, Cd1, Hg1), have been synthesized. In all complexes, the metal center is tridentately chelated by the ligand and further coordinated by two chlorine atoms, resulting in distorted trigonal bipyramidal geometry. The improvement in conversion efficiency of dye-sensitized solar cell was achieved by the complexes (M) and N719 co-sensitizing ZnO photoelectrode. In the tandem structure of M/N719/ZnO, the M forms a re-organization of energy level due to its single-crystal structure, which is advantageous to the electron injection and the hole recovery. The result demonstrates the M/N719 co-sensitized solar cell exhibited excellent photovoltaic performances with the short-circuit photocurrent density of 8.943 mA cm−2, the open-circuit photovoltage of 591 mV and the fill factor of 0.639 under standard global AM 1.5 solar irradiation conditions.

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► Three five-coordinate transition metal complexes were synthesized and designed to be a new type of sensitizer for solar cells.
► The effect of the complex on ZnO-based dye-sensitizer solar cells was investigated.
► The overall conversion efficiency of ZnO-based dye-sensitized solar cells is successfully improved by co-sensitizing.