Down-converting lanthanide doped TiO2 photoelectrodes for efficiency enhancement of dye-sensitized solar cells

Lanthanide (Ln3+) doped TiO2 down-conversion photoelectrodes (Ln3+ = Eu3+ and Sm3+ ions) are used to enhance the photovoltaic efficiency of dye-sensitized solar cells (DSSC). We report on achieving fill factors of 0.67 and 0.69 and efficiencies of 5.81% and 5.16% for Sm3+ and Eu3+, respectively. This is compared to the 4.23% efficiency for the undoped-titania photoelectrodes. This enhancement is probably due to the improved UV radiation harvesting via a down-conversion luminescence process by the lanthanide ions. The structure, optical and photoluminescence properties of the down-converting photoelectrode are characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray (EDX) and room temperature photoluminescence excitation and emission spectrofluorimetric measurements.

Research highlights
► Lanthanide (Ln3+ = Sm3+ and Eu3+) doped TiO2 acts as good down-converting materials for harvesting UV light from solar radiation into visible range.
► Modification of the photovoltaic efficiency of dye-sensitized solar cells by using photoelectrodes based on lanthanide (Ln3+ = Sm3+ and Eu3+) doped TiO2 down-converting materials.