Dielectric properties of Fe-doped TiO₂nanoparticles synthesised by sol–gel route

Abstract

Fe-doped nanocrystalline samples of titanium oxide have been synthesised by sol-gel route and conventional sintering process at 450 C under atmospheric conditions. These samples are characterised by X-ray diffraction (XRD), X-ray photoelectron spectroscopy, transmission electron microscopy (TEM) and dielectric property measurement. Samples with Fe content more than 4 mole% crystallises in rutile phase and those with less than 4 mole% crystallises in anatase phase. Nanocrystallite size has been controlled by Fe doping. Crystallite size was found to decrease with Fe concentration in the anatase phase samples whereas reverse happens in rutile phase samples of titanium oxide. There is a slight variation in numerical values of crystallite sizes measured by the two techniques: TEM and XRD peak broadening. The highest crystallite size was 86 nm in 10 mole% Fe-doped samples and the lowest 20 nm in 4 mole% Fe-doped sample. Large dispersions and anomalous values of the dielectric constant, "r were observed at low frequency in anatase phase samples. Rutile phase samples exhibit little dispersion over the measurement frequency range of 20 Hz to 10 MHz. The dielectric constant value of all the samples stabilises to a constant value at higher frequencies. This value is dependent on the final crystalline phase but independent of the crystallite size. The anomalous dielectric behaviour of anatase samples at low frequencies is assigned to the adsorbed -OH ions on the sample surface.

The Effect of Co doping on Structural, Optical and Dielectric Behaviour of TiO2 Nanoparticles

“…The high conductivity at the large frequency values confirmed the hopping of charge carriers between localised states. These results have been further supported by Fe, Sm and Al doped TiO 2 nanostructures [12][13][14] .…”

Photodegradation of Direct Blue‐199 in carpet industry wastewater using iron‐doped TiO2 nanoparticles and regenerated photocatalyst

“…The average particles size, which was obtained from the histogram, has good agreement with the average particle size, which was calculated using Scherrer's formula in the XRD analysis. Singh et al . reported that synthesized Fe‐doped TiO 2 nanoparticles have a spherical shape with a wide particle size range from 20 to 80 nm.…”

Optic and Dielectric Properties of Different Amount NiFe2O4Nanoparticles Loaded Hydrogels: Synthetic Circuits Applications

“…The nanoparticles are clearly seen in the SEM images (2μ) and amounts of NPs density in the hydrogels are increases with the increasing dose. 18,28 Frequency and applied bias voltage evolution dependent dielectric measurements.-Dielectric properties of the different amounts (2.5%, 5.0%, 7.5% and 10.0%) NiFe 2 O 4 NPs loaded hydrogels with direct current (dc) and alternative current (ac) have been investigated from the tangent factor and capacitance values. The different amount NiFe 2 O 4 NPs loaded hydrogels have been characterized by the UV-Vis absorption spectroscopy at RT.…”

“…Recently major research has been focused on the fabrication and characterization of nano particle doped dielectric materials, because the available technology requires very small size particles to vest-pocket components and microwave devices. 18 Especially, nano particle loaded dielectric materials has been benefited in wide applications such as gas sensing devices, 19 electro-optic, 20 chemical sensors, 21 photo-catalytic devices, 22 high power optoelectronic devices 23 and photoelectric devices 24 due to its high or low dielectric constants. Also, nano particle loaded dielectric materials in the visible spectral region can be made transparent electrically conductive.…”