Effect of precipitating agent NaOH on the synthesis of SrTiO <inf>3</inf> /TiO <inf>2</inf> heterostructure for dye-sensitized solar cells

Abstract

© 2019 Elsevier B.V. In this work, the effect of precipitating agent NaOH on the growth of SrTiO 3 blocking layer to serve as the charge recombination barrier for DSSC based TiO 2 were investigated. The SrTiO 3 /TiO 2 heterostructure was synthesized by the hydrothermal method. The structure and surface morphology of SrTiO 3 /TiO 2 heterostructure were carried out by SEM, TEM and XRD characterization techniques. The optical band gap of TiO 2 NR and SrTiO 3 /TiO 2 heterostructure were studied by the UV–visible spectrophotometer. The estimated band gap of TiO 2 nanorod and SrTiO 3 /TiO 2 heterostructure were typically 3.0–3.1 eV. At the best condition for fabrication (0.001 M NaOH), the SrTiO 3 /TiO 2 heterostructure photoanode achieves the highest photo-conversion efficiency of 2.68%, which is 38% higher than the bare TiO 2 nanorod photoanode (1.93%). By further analysis with the EIS, the results reveals that the added SrTiO 3 blocking layer is enhanced the DSSCs performance by prolonging the charge recombination and also improve the charge transfer resistance in the photoanode.