Determination of the band gap of TiO2–Al2O3 films as a function of processing parameters

Barajas-Ledesma, Edgar; García-Benjume, M.L.; Espitia‐Cabrera, I.; Ortíz-Gutiérrez, Mauricio; Espinoza‐Beltrán, F.J.; Mostaghimi, J.; Contreras-Garcı́a, M.E.

doi:10.1016/j.mseb.2010.05.001

Cited by 40 publications

(24 citation statements)

References 17 publications

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“…This plot can be used to calculate the band gap energy of the samples. The estimation of optical band gap from absorption coefficient data as a function of wavelength is actually related to Tauc's relation [13,14],…”

Section: Resultsmentioning

confidence: 99%

Tuning the absorption of ultraviolet spectra and optical parameters of aluminum doped PVA based solid polymer composites

Aziz

Ahmed

Hussein

et al. 2015

J Mater Sci: Mater Electron

154

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In this research work PVA:xAl (0.01 B x B 0.05) based solid polymer composites have been prepared by solution cast technique. The transmittances of the samples are decreased with increasing Al powder concentration. The absorption spectra of the samples are shifted to higher wavelengths which indicate their importance for shielding. The increase of absorption intensity in UV region was observed. The clear shift of absorption edge upon the addition of Al powder content indicated the decrease of energy band gap. The increase of extinction coefficient at high wavelengths for the samples containing Al powder revealed the loss of photon energy. The refractive indexes of the doped samples are increased compared to that of pure PVA.The linear relationship between the refractive index and volume fraction indicates a good dispersion of Al powder in PVA host polymer. The direct optical band gap measured from the plot of (aht) 2 versus photon energy (ht) showed a decreasing trend with increase of Al content. The Urbach energy was found to increase with increasing aluminum concentration. The complex optical dielectric functions were used to determine the type of electron transition.

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Section: Resultsmentioning

confidence: 99%

Tuning the absorption of ultraviolet spectra and optical parameters of aluminum doped PVA based solid polymer composites

Aziz

Ahmed

Hussein

et al. 2015

J Mater Sci: Mater Electron

154

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“…Furthermore, no significant changes in the surface morphology of titania‐alumina composite could be observed with increasing annealing temperature. It is expected at the optimum annealing temperature (500° C), strong interaction of the aluminum from the oxides of alumina with the TiO 2 lattice ,. Energy dispersive X‐ray analysis of the composite (Figure c) was found to show that the composition of oxides were approximately as TiO 2 ∼74 %, Al 2 O 3 ∼26 %.…”

Section: Resultsmentioning

confidence: 94%

“…The reduction in the band gap value observed for the sample. The reason for band gap reduction is due to the alumina dopant which could alter the TiO 2 semiconductor from intrinsic to an extrinsic . The absence of significant peak shift for Ti (2p) core level region from the XPS spectra of the composite could be attributed to the limited level of Al doping onto the very thin film of TiO 2 lattice.…”

Section: Resultsmentioning

confidence: 99%

New Insight into Understand the Enhanced Photoconductivity Properties of Ti (O₂) Plate Spurted with Al₂O₃ for Water Oxidation

et al. 2016

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The development of efficient, economic and environmentally friendly photoanode remains the primary materials challenge in the establishment of a scalable technology for solar water oxidation. Thus, for the simple materials such as Titania (TiO2) and its composites, was prepared by an easy method and studied extensively. High efficiency photoanode materials require properties like light trapping, electron and hole transportation. To provide a more efficient large scale TiO2 coating, we introduce a high throughput methodology wherein Al2O3 was spurted on titanium (Ti) plate. Photocurrents corresponding to water oxidation, under a standard AM 1.5G solar illumination, in a photoelectrochemical cell using Al2O3 spurted TiO2 film as photoanode was investigated and highest photocurrent of 40 μA cm−2 at zero bias vs (Ag/AgCl) was achieved when compared to pure TiO2. The light absorbing capability of the Al2O3 spurted TiO2 photoanode was demonstrated from the UV‐Visible diffuse reflectance spectra and decrease in the band gap of 0.13 eV for the TiO2 film was observed which could be attributed to the improved photocurrents due to the increased charge carriers on the TiO2 film. Increase of charge carrier concentration on the TiO2 film could be effected due to the passivation of surface states upon Al2O3 spurting.

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“…For the HVOF and WSP coatings, secondary absorption edges also exist at 2.34 eV and 2.22 eV, respectively. The main absorption edge at E bg (1) corresponds to non-stoichiometric TiO 2 features in rutile, and the secondary absorption edge at E bg (2) corresponds to an absorption tail of delocalized electronic states with a low excitation energy [19,21,22]. The existence of a secondary absorption edge does not seem to correlate tightly with the acetone photo-decomposition.…”

Section: Resultsmentioning

confidence: 95%

Structural and photocatalytic characteristics of TiO2 coatings produced by various thermal spray techniques

Ctibor¹,

Štengl²,

Pala³

2013

J Adv Ceram

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Titanium dioxide (TiO 2 ) was elaborated by four different thermal spray techniques-(i) plasma spraying using a water-stabilized torch, (ii) plasma spraying using a gas-stabilized torch, (iii) high velocity oxy-fuel gun, and (iv) oxy-acetylene flame. The porosity of the coatings was studied by optical microscopy, nano-structural features by scanning electron microscopy (SEM), phase composition by X-ray diffraction (XRD); the microhardness, surface roughness and wear resistance were evaluated. The diffuse reflectance was measured by ultra-violet/visible/near-infrared (UV/Vis/NIR) scanning spectrophotometer. The kinetics of photocatalytic degradation of gaseous acetone was measured under a UV lamp with 365 nm wavelength. After all the applied spray processes, the transformation of anatase phase from the initial powders to rutile phase in the coatings occurred. In spite of this transformation, all the coatings exhibited certain photocatalytic activity, which correlated well with their band gap energy calculated from reflectivity. All the coatings offer relatively good mechanical properties and can serve as robust photocatalysts.

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Determination of the band gap of TiO2–Al2O3 films as a function of processing parameters

Cited by 40 publications

References 17 publications

Tuning the absorption of ultraviolet spectra and optical parameters of aluminum doped PVA based solid polymer composites

Tuning the absorption of ultraviolet spectra and optical parameters of aluminum doped PVA based solid polymer composites

New Insight into Understand the Enhanced Photoconductivity Properties of Ti (O₂) Plate Spurted with Al₂O₃ for Water Oxidation

Structural and photocatalytic characteristics of TiO2 coatings produced by various thermal spray techniques

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Determination of the band gap of TiO2–Al2O3 films as a function of processing parameters

Cited by 40 publications

References 17 publications

Tuning the absorption of ultraviolet spectra and optical parameters of aluminum doped PVA based solid polymer composites

Tuning the absorption of ultraviolet spectra and optical parameters of aluminum doped PVA based solid polymer composites

New Insight into Understand the Enhanced Photoconductivity Properties of Ti (O2) Plate Spurted with Al2O3 for Water Oxidation

Structural and photocatalytic characteristics of TiO2 coatings produced by various thermal spray techniques

Contact Info

Product

Resources

About

New Insight into Understand the Enhanced Photoconductivity Properties of Ti (O₂) Plate Spurted with Al₂O₃ for Water Oxidation