INVESTIGATION OF THE FABRICATED TECHNOLOGY OF FREE-STANDING TIO₂ NANOTUBE MEMBRANES AND TIO₂/FTO TRANSPARENT PHOTOELECTRODE

The large-scale,highly-ordered,vertically-oriented free-standing TiO₂ nanotube membranes were fabricated by three-step anodization Ti foils in ethylene glycol containing 0.25w（NH4F）%.Then the as-prepared free-standing membranes were transferred to FTO-coated glass substrates with TiO₂ sol,and the transparent TiO₂/FTO photoelectrode was obtained after annealing treatment.The morphologies,crystalline phase,optical properties were characterized using FE-SEM,XRD and UV-Vis-NIR spectrophotometer,respectively.To some extent,the structural parameters of the free-standing TiO₂ nanotube membranes（inner diameter,nanotube length,and wall thickness）are controllable.After the membranes were transferred onto the FTO-coated glass substrate,we can obtain the high quality and multi-application TiO₂/FTO photoelectrode.At the same time,it is found that the optical energy gap(Eg) of TiO₂ nanotube membranes could be effectively modulated by different anodic oxidation voltage.Obviously,this work would be beneficial to apply in organic-inorganic photovoltaic devices.