Enhancing photovoltaic performance of dye-sensitized solar cells by rare-earth doped oxide of SrAl 2 O 4 :Eu 3+

Abstract SrAl 2 O 4 :Eu 3+ down-conversion (DC) nanocrystals were synthesized by a sol–gel method and then doped in TiO 2 as a photoanode in dye-sensitized solar cells (DSSCs). Differential thermal analysis, fourier transform infrared spectroscopy, X-ray diffraction and Brunauer–Emmet–Teller analysis confirmed the formation of SrAl 2 O 4 :Eu 3+ nanocrystals with diameters of ∼47 nm, pore size of ∼25 nm, sintering temperature of 1300 °C. The photoluminescence and UV–vis absorption spectra of the SrAl 2 O 4 :Eu 3+ revealed a DC from ultraviolet light to visible light which matched the strong absorbing region of the N719 dye. The photoelectric conversion efficiency of the DSSCs with a TiO 2 photoanode doped with 3 wt% SrAl 2 O 4 :Eu 3+ was 20% higher than that with a pure TiO 2 photoanode. This phenomenon could be mainly explained by SrAl 2 O 4 :Eu 3+ nanocrystals’ ability of DC and increased the short-circuit current density. It could be minorly due to the p-type doping effect and slightly improved the open-circuit voltage.