Aminosilicate modified mesoporous anatase TiO2@graphene oxide nanocomposite for dye-sensitized solar cells

Abstract

Highly ordered aminosilicate modified mesoporous anatase TiO2 graphene oxide (mTiO2@GO/NH2) nanocomposite microspheres are prepared by hydrothermal method and are investigated using various spectral and microscopic techniques. X-ray photoelectron spectroscopy and Fourier-transform infrared spectral analyses confirmed the presence of NH2 groups in the mTiO2@GO/NH2 nanocomposites. The mTiO2@GO/NH2 exhibits lower photoluminescence intensity than bare mesoporous TiO2 microspheres, disclosing an efficient photoelectron transfer from the mesoporous TiO2 to GO through aminosilicate chain. Atomic force microscopic analysis reveals that mTiO2@GO/NH2 thin film has highly ordered porous structure. The highly porous mTiO2@GO/NH2 exhibits good dye loading for light harvesting and allow good electrolyte contact, which minimizes the back-electron transfer between photoanode and oxidized dye molecules. The dye-sensitized solar cell (DSSC) based on mTiO2@GO/NH2 nanocomposite photoanode, with optimum amount of (3-aminopropyl)triethoxysilane (APTES), delivers an overall photo-conversion efficiency of 5.11%, which is 2.5-fold higher than that of the DSSC based on pure mesoporous TiO2 microspheres (mTiO2 MS) photoanode. The significant photovoltaic performance of the present DSSC based on mTiO2@GO/NH2 photoanode is due to synergistic effects between the TiO2 and GO heterojunction.