Environment friendly template-free microwave synthesis of submicron-sized hierarchical titania nanostructures and their application in photovoltaics

A simple low-temperature microwave synthesis of hierarchical nanostructures (HNSs) of titania in DI water is reported. A great advantage of the reported method is the production of submicron-sized HNSs without any surfactant or hydrofluoric acid. The hierarchical morphology provides huge surface area for maximum exposure for light-driven reactions, and the 3D folding morphology allows further scattering of light to obtain its maximum utilization. FESEM, TEM, XRD, BET surface area measurement, UV/VIS and Raman spectroscopy were utilized to understand the structures. The mechanism of formation of nanostructures is also discussed. The nanostructures were employed in dye-sensitized solar cells for performance comparison.