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See detailOptical and structural characterization of TiO2 films doped with silver nanoparticles obtained by sol-gel method
Ivanova, T.; Harizanova, A.; Koutzarova, T. et al

in Optical Materials (2013), 36

Nanostructured titanium oxide films with incorporated Ag nanoparticles were deposited by sol-gel spin coating method. The films were annealed at 300 °C, 400 °C, 500 °C and 600 °C in oxygen and nitrogen ... [more ▼]

Nanostructured titanium oxide films with incorporated Ag nanoparticles were deposited by sol-gel spin coating method. The films were annealed at 300 °C, 400 °C, 500 °C and 600 °C in oxygen and nitrogen ambient. X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and UV-VIS spectroscopy had been applied for studying the influence of the thermal treatments and the gas ambient on the structural and optical properties of TiO2 and TiO2:Ag films. The XRD analysis revealed the presence of metallic Ag phase without traces of silver oxides and these results were confirmed by FTIR spectra. It has been revealed that the annealing temperatures and the ambient, where the annealing is carried out is crucial for TiO2 crystallization, when there is Ag incorporation and especially for appearance of anatase and rutile phase. The nitrogen and oxygen ambient influences quite different the crystallization of TiO2:Ag films. Transmission and absorption spectra have been analyzed. Optical band gap values were evaluated for pure titania and Ag incorporated TiO2 films. © 2013 Elsevier B.V. All rights reserved. [less ▲]

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See detailPreparation and characterisation of Ag incorporated Al2O3 nanocomposite films obtained by sol-gel method
Ivanova, T.; Harizanova, A.; Koutzarova, T. et al

in Crystal Research and Technology (2012), 47(5), 579-584

Sol-gel route has been applied for a deposition of the thin films of aluminum oxide and Ag embedded in Al2O3 films. The films are spin-coated on Si and quartz substrates with the film thickness of 120 nm ... [more ▼]

Sol-gel route has been applied for a deposition of the thin films of aluminum oxide and Ag embedded in Al2O3 films. The films are spin-coated on Si and quartz substrates with the film thickness of 120 nm. XRD analysis has been used for the determination of the film structure. FTIR spectroscopy is applied for studying vibrational properties of the obtained coatings. Optical characterization is done by UV-VIS spectroscopy. The formation of Ag nanoparticles has been confirmed by XRD and optical data. The sol-gel process is found to be useful technology for incorporation of Ag nanoparticles in the metal oxide matrices. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. [less ▲]

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See detailPreparation and characterization of ZnO-TiO(2) films obtained by sol-gel method
Ivanova, T.; Harizanova, A.; Koutzarova, T. et al

in Journal Of Non-Crystalline Solids (2011), 357(15), 2840-2845

The sol-gel route has been applied to obtain ZnO-TiO(2) thin films. For comparison, pure TiO(2) and ZnO films are also prepared from the corresponding solutions. The films are deposited by a spin-coated ... [more ▼]

The sol-gel route has been applied to obtain ZnO-TiO(2) thin films. For comparison, pure TiO(2) and ZnO films are also prepared from the corresponding solutions. The films are deposited by a spin-coated method on silicon and glass substrates. Their structural and vibrational properties have been studied as a function of the annealing temperatures (400-750 degrees C). Pure ZnO films crystallize in a wurtzite modification at a relatively low temperature of 400 degrees C, whereas the mixed oxide films show predominantly amorphous structure at this temperature. XRD analysis shows that by increasing the annealing temperatures, the sol-gel Zn/Ti oxide films reveal a certain degree of crystallization and their structures are found to be mixtures of wurtzite ZnO, Zn(2)TiO(4), anatase TiO(2) and amorphous fraction. The XRD analysis presumes that Zn(2)TiO(4) becomes a favored phase at the highest annealing temperature of 750 degrees C. The obtained thin films are uniform with no visual defects. The optical properties of ZnO-TiO(2) films have been compared with those of single component films (ZnO and TiO(2)). The mixed oxide films present a high transparency with a slight decrease by increasing the annealing temperature. (C) 2011 Elsevier B.V. All rights reserved. [less ▲]

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See detailStudy of ZnO sol-gel films: Effect of annealing
Ivanova, T.; Harizanova, A.; Koutzarova, T. et al

in Materials Letters (2010), 64(10), 1147-1149

Thin films of zinc oxide were deposited by spin coating method on different substrates. The obtained samples were thermally treated at temperatures from 400 degrees C up to 850 degrees C. The structural ... [more ▼]

Thin films of zinc oxide were deposited by spin coating method on different substrates. The obtained samples were thermally treated at temperatures from 400 degrees C up to 850 degrees C. The structural study was performed by XRD and FTIR techniques in order to observe the effect of the annealing temperatures. The sol-gel ZnO films showed polycrystalline hexagonal structure. The optical transmittance reached 91% and it diminished with increasing annealing temperatures. (C) 2010 Elsevier B.V. All rights reserved. [less ▲]

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See detailEffect of annealing temperatures on properties of sol-gel grown ZnO-ZrO2 films
Ivanova, T.; Harizanova, A.; Koutzarova, T. et al

in Crystal Research And Technology (2010), 45(11), 1154-1160

Mixed ZnO-ZrO2 films have been obtained by sol-gel technology. By using spin coating method, the films were deposited on Si and glass substrates. The influence of thermal annealings (the temperatures vary ... [more ▼]

Mixed ZnO-ZrO2 films have been obtained by sol-gel technology. By using spin coating method, the films were deposited on Si and glass substrates. The influence of thermal annealings (the temperatures vary from 400 degrees C to 750 degrees C) on their structural properties has been studied. The structural behavior has been investigated by the means of XRD and FTIR techniques. The results revealed no presence of mixed oxide phases, the detected crystal phases were related to the hexagonal ZnO and to crystalline ZrO2. The sol-gel ZnO-ZrO2 films showed polycrystalline structure with a certain degree of an amorphous fraction. The optical transmittance reached 91% and it diminished with increasing the annealing temperatures. The optical properties of the sol-gel ZnO-ZrO2 films, deposited on glass substrates are excellent with high transparency and better then those of pure ZrO2 films, obtained at similar technological conditions. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim [less ▲]

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See detailElectrochromic TiO2, ZrO2 and TiO2-ZrO2 thin films by dip-coating method
Ivanova, T.; Harizanova, A.; Koutzarova, T. et al

in Materials Science & Engineering : B (2009), 165(3), 212-216

Sol-gel processing of TiO2, ZrO2 and mixed Ti/Zr oxide thin films has been studied as application of these coatings in electrochromic devices. Their structural transformations as a function of annealing ... [more ▼]

Sol-gel processing of TiO2, ZrO2 and mixed Ti/Zr oxide thin films has been studied as application of these coatings in electrochromic devices. Their structural transformations as a function of annealing temperatures were analyzed by XRD and FTIR techniques. Electrochromic behavior of the three kind materials was investigated by cyclic voltammetry and the basic electrochromic characteristics were determined. (c) 2009 Elsevier B.V. All rights reserved. [less ▲]

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