Piezoelectric Behavior of Self-Organized Titanium Dioxide Nanotubes

In this paper, titanium dioxide nanotubes are successfully made through the anodic oxidation approach using a 5% hydrofluoric acid-containing glycerol solution. Surface morphology observation on the nanotubes using high resolution scanning electron microscopy shows inverted funnel shape. Transmission electron microscopic analysis reveals a crystalline structure of the nanotubes. The piezoelectric behavior of titanium oxide nanotubes has been demonstrated by three point bending tests. The deformation caused by three point bending generates voltage differences at the two ends of the samples. The larger the deflection, the higher the absolution value of the voltage is. The deformation induced voltage difference is affected by the size of the nanotubes. The nanotubes with larger diameters show better repeatability. This behavior may be related to the damage tolerance of the nanotubes under bending. It is concluded that self-organized titanium oxide nanotubes have the potential to be used as the material for small energy harvesters or power generators due to their piezoelectric property at nanoscale.