Enhancing photoelectrical performance of dye–sensitized solar cell by doping SrTiO3:Sm3+@SiO2 core–shell nanoparticles in the photoanode

Abstract

SrTiO3:Sm3+@SiO2 (STS@SiO2) core–shell nanoparticles were fabricated by Stöber method after a simple hydrothermal process and then being introduced into the TiO2 photoanode to assemble dye–sensitized solar cells (DSSCs). X–ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR) and transmission electron microscope (TEM) analysis confirmed the formation of core–shell nanoparticles with cubic structured SrTiO3:Sm3+ (STS) as core, SiO2 as shell. The photo–fluorescence (PL) and ultraviolet–visible (UV–Vis) absorption spectra of photoanodes with different STS@SiO2 content indicate a down–conversion from ultraviolet light to visible light which matched the strong absorbing region of the N719 dye. Compared with the pure TiO2 and STS doped TiO2 photoanode, STS@SiO2 doped TiO2 photoanode showed a greater photovoltaic efficiency. The photoelectric conversion efficiency (η) of 5.07% for 10 wt% STS@SiO2 doped TiO2–based DSSC was higher than that of 3.72% for pure TiO2–based DSSC and 4.29% for 10 wt% STS doped TiO2–based DSSC. This phenomenon could be explained by STS@SiO2 core–shell nanoparticles’ triple ability to extend spectral response range to the ultraviolet region, suppress the recombination of electron–electrolyte and lengthen the light traveling distance in the photoanode by the scattering.