Bi-layered photoelectrodes of TiO2/activated carbon modified with SrTiO3 films boosted sunlight harvesting of dye-sensitized solar cells

Abstract

• Bi-layered photoanodes were fabricated for dye-sensitized solar cells (DSSCs). • Photoanodes were composed of 0.05 % activated carbon (AC)/TiO 2 and SrTiO 3 layers. • SrTiO 3 perovskite material amount was changed from 5 to 30 % in second layer. • Champion DSSC was composed of 0.05 % AC/TiO 2 –25 % SrTiO 3 photoelectrode. • Highest η = 5.90 %, V OC = 714.71 V, J SC = 14.91 mA/cm 2 , FF = 55.46 % were measured. This work studies the effect of the value of SrTiO 3 material on both the characteristics of 0.05 % activated carbon (AC)/TiO 2 –(5–30 %) SrTiO 3 nanocomposites layers as well as performances of dye-sensitized solar cells (DSSCs). Synthesis of SrTiO 3 as an inorganic perovskite nanocrystalline layer was done by the sol-gel procedure and applied for preparation of various 0.05 % AC/TiO 2 –SrTiO 3 (0–30 %) photoanode nanocomposites for DSSCs. Observing the Sr-element peak in the EDS diagram confirmed the existence of the SrTiO 3 in the composite. The champion DSSC containing the optimum 0.05 % AC/TiO 2 –25 % SrTiO 3 composite illustrated the highest efficiency of η = 5.90 ± 0.01 %. Thus, the 0.05 % AC/TiO 2 –25 % SrTiO 3 nanocomposite enhanced the PCE by about 57 % in comparison with reference device containing bare TiO 2 indicating η = 3.15 ± 0.01 %. Evidently, SrTiO 3 incorporation into the TiO 2 raised J SC and V OC values of devices relative to those measured for solar cell with pristine TiO 2 . Based on electrochemical impedance spectroscopy (EIS) data, in comparison with various concentrations of SrTiO 3 , 0.05 % AC/TiO 2 –SrTiO 3 (25 %) photoelectrode illustrated minimum R CT2 = 29.04 Ω.cm −2 . Improved charge transfer was observed by increasing the value of SrTiO 3 material to minimize recombination. Therefore, application of 0.05 % AC/TiO 2 -SrTiO 3 photoelectrode nanocomposites could highly boost DSSCs performances.