Ag Decorated TiO2 Nanoparticles Synthesized by Rapid Photo Deposition Technique as Electron Transport Layer (ETL) for Dye-Sensitized and Perovskite Solar Cells

Abstract

Electron transport layer is one of the important part in the dye-sensitized and perovskite solar cells which is responsible for the transport of photo-generated electrons to the outer circuit. Thus, selection of appropriate Electron transport layer (ETL) is important for attaining higher power conversion efficiency. Localised surface plasmon resonance can be used as a strategy to improve the total light absorption and it also has been reported that the metallic nanoparticles induce localized electric field, which can excite dye/perovskite molecules more effectively than far-field light which would lead to enhanced light absorption by the adsorbed dye/perovskite molecule which in turn would result in improved generation of photo-excited electrons. In this work TiO2 nanoparticles were synthesized by a simple solvothermal method and the Ag nanoparticles were decorated over TiO2 by photo deposition technique. The X-ray diffraction analysis of the sample showed characteristic peaks for anatase phase of TiO2 and the Ag decorated TiO2 showed peaks corresponding to (200) planes of Ag nanoparticles. Optical properties were studied using UV-visible absorption analysis and it showed strong absorption in the UV region for TiO2 and the surface plasma resonance (SPR) effect is observed in Ag decorated samples. TEM analysis showed the presence of near-spherical shape Ag nanoparticles which were present uniformly over TiO2 nanoparticles. XPS analysis revealed the chemical states of the prepared material. For the constructed DSSC using the prepared material, open circuit voltage (Voc) of 0.67 V and 0.69 V and efficiency (η) of 5.4 and 7.3 % were obtained for bare TiO2 and Ag decorated TiO2 based solar cells respectively. A similar trend of enhanced performance was observed for the Ag decorated TiO2 when compared to bare TiO2 when used as ETL layer in the case of perovskite solar cells as well.