Photovoltaic and spectroscopic characteristics of perovskite/TiO2 heterostructure photoanodes for improving the efficiency of dye sensitized solar cells

Abstract

Perovskite-type ternary oxide nanostructured materials have gained great attention in recent years as promising materials for solar cell applications. However these ternary oxides have failed to be applied as a working electrode in DSSCs due to its poor performance and its inability to bind dye molecules to the surface. A heterostructure perovskite/TiO2 photoactive electrodes is a new strategy to improve the photon-to-current efficiency (PCE) of DSSCs. In this paper, BaZrO3 (BZ), BaTiO3 (BT) and nanocomposite [1:1] molar% from BaTiO3-BaZrO3 perovskite nanostructured materials synthesized via sonochemical sol-gel methods, are coated on the top of the TiO2 photoactive electrode. This heterostructured (perovskite/TiO2) photoelectrode has been applied for improving the performance of dye-sensitized solar cells (DSSCs). The crystallographic, morphological and optical characteristics of the different prepared perovskite nanomaterials has been investigated by XRD, SEM, TEM, Raman and UV-Vis Diffuse reflectance spectroscopic analysis, respectively. Dye-sensitized solar cells based on the different heterostructure perovskite/TiO2 electrodes are assembled, and high conversion efficiency (η) are calculated from the current density-voltage (J-V) characteristics of the solar cells. The results show an efficiency enhancement with about ∼22%, 37% and 51% in case of BZ, BTZ and BT respectively. These enhancements is attributed to high refractive index of the perovskite nanoparticles, higher incident photon-to-current conversion yield which is due to greater fraction of light scattered, as well as the less recombination of the photogenerated electrons.