title: Hierarchically structured suspended TiO2 nanofibers for use in UV and pH sensor devices.
abstract: Photoelectrochemical sensors based on hierarchically structured titanium dioxide (TiO2) nanofibers (NFs) were fabricated by combination of electrospinning, carbon microelectromechanical systems (MEMS), and hydrothermal reaction. During the electrospinning step, a rotating drum collector was used to align and position NFs of titanium tetraisopropoxide (TTIP) in polyvinylpyrrolidone (PVP) on top of a carbon-MEMS structure. Following calcination under vacuum, a stable ohmic contact was obtained between suspended TiO2-carbon NFs (TiO2/C NF) and the carbon electrodes. Subsequent to this, a hierarchical nanostructure of TiO2 nanowires (TiO2 NWs) was hydrothermally synthesized onto the TiO2/C NFs and successfully utilized as UV and pH sensors. This is the first demonstration of a semiconductor-based nanofiber sensor suspended on carbon electrodes that has been achieved by a relatively simple and cost-effective electrospinning method. Furthermore, these sensors demonstrate a high sensitivity, as well as a stable ohmic contact, due to the large surface area of the TiO2 NWs and the carbon-carbon contact between the suspended TiO2/C NFs and carbon electrodes.
authors.affiliation: Department of Biomedical Engineering, School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST) , Banyeon-ri 100, Ulsan, 689-798, Republic of Korea.
authors.forename: Won Seok
authors.initials: WS
authors.lastname: Lee
authors.forename: Yang-Seok
authors.initials: YS
authors.lastname: Park
authors.forename: Yoon-Kyoung
authors.initials: YK
authors.lastname: Cho