Improved efficiency of dye-sensitized solar cells by doping of strontium aluminate phosphor in TiO₂ photoelectrode

SrAl₂O₄:Eu²⁺, Dy³⁺ phosphor was synthesized by chemical solution route to use as a dopant in TiO₂ layer employed as a photoelectrode for down conversion of ultraviolet and near-ultraviolet to visible and near-infrared light in a dye-sensitized solar cell. Nano-crystalline structure of the SrAl₂O₄:Eu²⁺, Dy³⁺ powder was confirmed by X-ray diffraction analysis and field emission scanning electron microscopy. Monitored at 520 nm, SrAl₂O₄:Eu²⁺, Dy³⁺ phosphor showed emission peaks at 460 to 610 nm due to 4f⁶ 4f⁷ transitions of Eu²⁺ ions. For the study, SrAl₂O₄:Eu²⁺, Dy³⁺ phosphor-doped TiO₂ layer was deposited on fluorine-doped tin oxide coated glass by electrostatic spray deposition. The short circuit current, open circuit voltage, fill factor, and conversion efficiency of the cells were measured. Experimental results revealed that the device efficiency for the SrAl₂O₄:Eu²⁺, Dy³⁺ phosphor-doped TiO₂ layer increased to 7.20 %, whereas that of the pure-TiO₂ photoelectrode was 4.13 %.