Morphological effects of reflux condensation on nanocrystalline anatase gel and thin films

Synthesis of anatase phase of titania is of great interest because of its efficiency in photocatalysis to produce renewable energy in different ways, one being dye sensitized solar cells (DSSC). In the present work reflux condensation is utilized to obtain stable anatase nanostructures from sol gel synthesis using titanium tetraisopropoxide (TTIP) precursor. The refluxing time affects the morphology of as synthesized titania and that of annealed films as well. This variation of morphology is studied and a possible explanation is made. Both XRD and TEM analysis reveal crystallite size to be less than 10 nm. SEM and TEM are used to study morphology which changes from rod like to spherical particles with increasing refluxing time. TGA shows anatase stability upto 700 °C and BET method reveals surface area to be larger than 120 m2 g−1. The films possess great potential for high efficiency when employed in devices.

► Refluxing with sol gel synthesis for easy, low cost production of nanocrystalline anatase for photovoltaic applications.
► Anatase is the only phase obtained as indicated by XRD.
► Nice agreement for crystallite size measurement from XRD and TEM being less than 10 nm.
► The morphology of the product changes from rods to spherical particles on increasing reflux condensation duration.
► From 24 h refluxed (rod like morphology) and 120 h refluxed (spherical particles) gels, doctor bladed films with adequate porosity and high surface area are obtained having strong potential for use as photoanode.