Journal ArticleDOI
Optical characterization of sol–gel derived Nb2O5 thin films
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TLDR
In this paper, the optical properties of thin Nb2O5 films, obtained by spin coating of Nb sol on glass and silicon substrates, were investigated using nonlinear curve fitting.Abstract:
The optical properties of thin Nb2O5 films, obtained by spin coating of Nb sol on glass and silicon substrates are investigated. The Nb sol was prepared by a sonocatalytic method using niobium chloride dissolved in ethanol. A calculation procedure for reliable and unambiguous determination of optical constants (refractive index and extinction coefficient) and thickness of films is developed that uses transmittance and reflectance measurements and non-linear curve fitting. By means of the developed procedure, the impacts of the sol ageing and the post deposition annealing on the optical properties and thickness of the films are investigated. It is demonstrated that films with controlled thicknesses and refractive index values in the range from 1.82 to 2.20 (at wavelength of 600 nm) could be obtained using different concentrations of the Nb sol and post deposition annealing in the range 60–650 °C. The possibility of fabrication of single layer anti-reflective coating for silicon is discussed.read more
Citations
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Journal ArticleDOI
Synthesis and physical properties of Ag doped niobium pentoxide thin films for Ag–Nb2O5/Si heterojunction device
Journal ArticleDOI
Investigation of Antireflection Nb₂O₅ Thin Films by the Sputtering Method under Different Deposition Parameters.
TL;DR: It is found that even if the deposition temperature was 400 °C, the deposited Nb2O5 thin films revealed an amorphous phase and no crystallization phase was observed, and the reflectance ratio, extinction coefficient, and refractive index curve results were influenced by the depositionTemperature and O2 ratio.
Journal ArticleDOI
Corrosion of thin, magnetron sputtered Nb2O5 films
Marina Fuser Pillis,Guilherme Altomari Geribola,Guilherme Scheidt,Edval Gonçalves de Araújo,Mara Cristina Lopes de Oliveira,Renato Altobelli Antunes +5 more
TL;DR: In this article, Niobium oxide based thin films were deposited on AISI 316 stainless steel substrates using reactive DC magnetron sputtering, and the corrosion behavior of the specimens was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization.
Journal ArticleDOI
Vapor responsive one-dimensional photonic crystals from zeolite nanoparticles and metal oxide films for optical sensing.
Katerina Lazarova,Hussein Awala,Sébastien Thomas,M. Vasileva,Svetlana Mintova,Tsvetanka Babeva +5 more
TL;DR: The preparation of responsive multilayered structures with quarter-wave design based on layer-by-layer deposition of sol-gel derived Nb2O5 films and spin-coated MEL type zeolite is demonstrated and the quasi-omnidirectional photonic band is predicted theoretically, and confirmed experimentally by reflectance measurements at oblique incidence with polarized light.
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Zeolite films as building blocks for antireflective coatings and vapor responsive Bragg stacks
Tsvetanka Babeva,Hussein Awala,M. Vasileva,Jaafar El Fallah,Katerina Lazarova,Sébastien Thomas,Svetlana Mintova +6 more
TL;DR: The reversible response of the Bragg stacks towards acetone without additional annealing opens up the possibility of preparing sensors with optical read-out by incorporation of sensitive and transducer elements into a single device.
References
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Thomas F. Coleman,Yuying Li +1 more
TL;DR: In this paper, a trust region approach for minimizing nonlinear functions subject to simple bounds is proposed, where the trust region is defined by minimizing a quadratic function subject only to an ellipsoidal constraint and the iterates generated by these methods are always strictly feasible.
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Behavior of the Electronic Dielectric Constant in Covalent and Ionic Materials
S. H. Wemple,M. DiDomenico +1 more
TL;DR: In this article, a single effectiveoscillator fit was used to analyze refractive-index dispersion data below the interband absorption edge in more than 100 widely different solids and liquids.
Journal ArticleDOI
Metal Oxides for Dye-Sensitized Solar Cells
TL;DR: The d-block binary metal oxides viz. TiO2, ZnO, and Nb2O5 are the best candidates as photoelectrode due to the dissimilarity in orbitals constituting their conduction band and valence band as discussed by the authors.
Journal ArticleDOI
Sol–gel electrochromic coatings and devices: A review
Jacques Livage,Dibyendu Ganguli +1 more
TL;DR: In this article, a brief updated review of sol-gel-derived electrochromic films of different chemical systems is presented, where performances of selected films measured in electrochemical cells or in devices are discussed and degradation problems experienced by different authors enumerated.
Journal ArticleDOI
Sol–gel niobium pentoxide: A promising material for electrochromic coatings, batteries, nanocrystalline solar cells and catalysis
TL;DR: In this article, the state of the art in the development of electrochromic (EC) coatings and devices, batteries, nanocrystalline solar cells and in the field of catalysis achieved during the last decade using sol-gel derived pure and doped niobium pentoxide.