Microwave-assisted hydrothermal synthesis of mesoporous anatase TiO2 via sol–gel process for dye-sensitized solar cells

Mesoporous titanium dioxide (TiO2) with highly crystalline anatase phase and high surface area is a promising material for energy and environmental application. In this study, a novel and facile method for rapid synthesis of mesoporous TiO2 via microwave-assisted hydrothermal route using stable and water-soluble titanium citrate complexes as the precursor was developed. The physicochemical properties of mesoporous TiO2 in terms of morphology, crystallization, optical property, surface area, and thermal behaviour were characterized by SEM, TEM, XRD, UV–vis spectroscopy, BET surface area analysis, and TGA/DTA, respectively. Results showed that the synthesized TiO2 contained mainly anatase phase with crystallite size of 5.0–8.6 nm at various hydrothermal temperatures and durations ranging from 150 to 180 °C and from 30 to 120 min, respectively. The specific surface areas of the TiO2 nanocrystals were 217–323 m2 g−1 with the pore diameter of 5.8–6.9 nm, clearly showing the mesoporous characteristics of the hydrothermal TiO2 nanocrystals. The mesoporous nanocrystals synthesized at 180 °C were then used to prepare the TiO2 photoelectrode using screen-printing deposition method. The MW180-120-based TiO2 photoanode exhibited a good efficiency on photocurrent conversion and the conversion efficiency was in the range 4.8–7.1%, depending on active area and film thickness. In addition, the overall conversion efficiency of the DSSC with active area of 1 cm2 and organic solvent electrolyte decreased slightly from 4.8% to 4.3% after being stored for more than 490 h, demonstrating the long-term stability of the DSSC used in this study.

The mesoporous titanium dioxide (TiO2) with high surface area and crystallinity synthesized by a novel microwave route enhance the photoconversion efficiency and long-term stability of DSSCs.Figure optionsDownload as PowerPoint slideResearch highlights
► The use of stable and water-soluble titanium citrate complexes as the precursor.
► Rapid synthesis of pure anatase with high surface area via microwave-assisted hydrothermal route.
► The dye-sensitized solar cells with active area of 1 cm2 has good photoconversion efficiency of 4.8%.
► Long-term stability of the dye-sensitized solar cells after 490 h of incubation.