Near band-edge electron diffusion in electrospun Nb-doped anatase TiO 2 nanofibers probed by electrochemical impedance spectroscopy

Abstract

Charge transport through Nb-doped anatase TiO2 nanofibers (diameter ∼100 nm) developed by electrospinning is studied under the framework of hopping transport using electrochemical impedance spectroscopy measurements. It is observed that the Fermi level of TiO2 rise close to its conduction band and result in a band-edge type diffusion mechanism even at low bias voltages when 2 at % Nb atoms replaces the Ti atoms in the anatase lattice. The Nb-doped anatase electrospun nanofibers showed high chemical capacitance, high effective diffusion coefficient, and lower transport resistance compared to the undoped samples and conventional nanoparticles (25 nm). © 2011 American Institute of Physics.