Optical properties of vanadium dioxide nanoparticles in nanoporous glasses

Sidorov, A. I.; Vinogradova, O. P.; Khrushcheva, T. A.; Obyknovennaya, I. E.; Ermolaeva, G. N.; Shilov, V. B.

doi:10.1364/jot.75.000033

Cited by 6 publications

(9 citation statements)

References 6 publications

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“…The data of simulations can be rescaled using normalizations given above, to any specific width of the semiconductor-to-metal transition curve for the particular setting and size of nanoparticles. It should be stressed that the very possibility of a phase transition in different nanocomposite samples with 3 -40 nm particles was proven experimentally in [18,19].…”

Section: ͑1͒mentioning

confidence: 95%

“…The smoothed steplike function S͑T͒ = ͕1 + tanh͓͑T − T pt ͒ / ␦T͔͖ / 2 of the temperature T describes the phase transition. The 10%-90% width of the semiconductor-to-metal transition curve at high temperature W is related with parameter ␦T by W Ӎ 2.2␦T (which amounts to ϳ11°C in nanoporous glass-VO 2 composites [18]). We used Maxwell Gar-…”

Section: ͑1͒mentioning

confidence: 99%

“…Importantly, the size of embedded nanoparticles influences the width of the hysteretic loop and the temperature of phase transition [8,19], as well as optical constants of composite material. Since experimental dependencies of complex dielectric constants on are not currently available, we used optical constants of VO 2 films [4], as well as results of experiments with nanoporous glasses [18] to estimate the range of variation of parameters. The data of simulations can be rescaled using normalizations given above, to any specific width of the semiconductor-to-metal transition curve for the particular setting and size of nanoparticles.…”

Section: ͑1͒mentioning

confidence: 99%

“…It can be used to achieve switchable reflectivity of nanocomposite layers [14]. However, for quasi-cw illumination the properties of VO 2 films [15] and nanoporous glass-VO 2 composites [16][17][18] are altered mostly by slow phase transition owing to light heating: a mechanism that is completely different from the ultrafast optically induced phase transition. Moreover, in thick nanocomposites with low concentration of doping nanoparticles ͑ ϳ 10 −2 % ͒ light propagation is affected not only by thermally induced changes of absorption but also by the corresponding refractive index variations [16,17].…”

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Light dynamics in glass-vanadium dioxide nanocomposite waveguides with thermal nonlinearity

Kartashov

Vysloukh

2009

Opt. Lett.

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We address the propagation of laser beams in SiO 2 -VO 2 nanocomposite waveguides with thermo-optical nonlinearity. We show that the large modifications of the absorption coefficient as well as notable changes of the refractive index of VO 2 nanoparticles embedded into the SiO 2 host media that accompany the semiconductor-to-metal phase transition may lead to optical limiting in the near-IR wave range. © 2009 Optical Society of America OCIS codes: 190.0190, 190.4400.The importance of thermal self-action of laser beams was realized almost 40 years ago [1,2]. In some materials, such as VO 2 , heating results in abrupt changes of absorption and refraction [3,4] owing to semiconductor-to-metal phase transition at T pt Ϸ 67°C. In VO 2 thin films such transitions can be driven optically at subpicosecond time scales [5,6]. The optical properties of VO 2 nanocomposites depend on sizes of the embedded particles [7][8][9], allowing various switching applications [7]. Such composites and films possess ultrafast nonlinearities [10] and enhanced absorption [11,12]. Phase transition is affected by the film morphology [13]. It can be used to achieve switchable reflectivity of nanocomposite layers [14]. However, for quasi-cw illumination the properties of VO 2 films [15] and nanoporous glass-VO 2 composites [16][17][18] are altered mostly by slow phase transition owing to light heating: a mechanism that is completely different from the ultrafast optically induced phase transition. Moreover, in thick nanocomposites with low concentration of doping nanoparticles ͑ ϳ 10 −2 % ͒ light propagation is affected not only by thermally induced changes of absorption but also by the corresponding refractive index variations [16,17]. Thus, exploration of laser beam dynamics in the waveguiding geometries is rather important. In this Letter we study light dynamics in SiO 2 -VO 2 nanocomposite waveguides for thermally induced semiconductor-to-metal phase transition. Optical limiting in this setting can be controlled by the initial system temperature and by the intensity of the input light beam.Light propagation in a planar waveguide formed by SiO 2 glass cladding and a glass core with embedded spherical VO 2 nanoparticles is described by the nonlinear Schrödinger equation for the dimensionless field amplitude q͑ , ͒: ͑1͒where is the propagation distance normalized to L dif = kx 0 2 , k =2n rh / , n rh is the real part of the refractive index of host material, and is the wavelength.The transverse coordinate is expressed in units of core width x 0 =10 m, while the function R͑͒ = exp͑− 8 ͒ describes the concentration profile of VO 2 nanoparticles. The parameter p r =2L dif ͑n rs − n rh ͒ / is the normalized difference of wavenumbers in the core (semiconducting phase is assumed) and the glass cladding; r = ͑n rm − n rs ͒ / ͑n rs − n rh ͒ is the normalized difference of refractive indices in metallic n rm and semiconducting n rs phases; and p i =2L dif ͑n is − n ih ͒ / characterizes the difference of imaginary parts of refractive indices, while i ...

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Section: ͑1͒mentioning

confidence: 95%

Section: ͑1͒mentioning

confidence: 99%

Section: ͑1͒mentioning

confidence: 99%

mentioning

confidence: 99%

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Light dynamics in glass-vanadium dioxide nanocomposite waveguides with thermal nonlinearity

Kartashov

Vysloukh

2009

Opt. Lett.

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“…Since then, many researchers have focused on the optical properties of sub-wavelength metal structure, the application of which is extended to nanolithography, optical storage, biochemical sensing, sub-wavelength imaging, and semiconductor light-emission. Moreover, several studies found that the phase transition temperature of VO 2 films can be decreased effectively by regulating film grain size [8,9]. In view of reversible SMPT, VO 2 films can be applied to smart windows by adopting a nanoparticle structure.…”

Section: Introductionmentioning

confidence: 99%

Optical properties of vanadium dioxide thin film in nanoparticle structure

Fang

Tong

et al. 2015

Optical Materials

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Vanadium(IV) coordination complexes with excellent biological activities: a synthetic, characterization, and density functional theory approach

Sharma

Das

Sadhu

et al. 2022

Journal of Coordination Chemistry

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The oxidovanadium(IV) complex [VO(HL) 2 ] (1) (where, HL = 4-nitrocinnamohydroxamate; 4-NO 2 C 6 H 4 CH=CHCONHOH) has been synthesized by the condensation reaction of VOSO 4 •5H 2 O and potassium 4-nitrocinnamohydroxamate in methanol-water medium. The complex is characterized by elemental analysis, molar conductivity, magnetic susceptibility measurement, FTIR, UV-Vis, Electron Paramagnetic Resonance (EPR) spectral techniques and mass spectrometry. The bidentate linkage of hydroxamate ligand involving O,O-coordination through hydroxamic and carbonyl oxygen atoms has been deduced. The magnetic susceptibility, EPR and mass spectra (ESI-MS) indicate that the complex exists as monomer and a distorted square pyramidal geometry around vanadium is proposed. The electrochemical study of 1 has shown it is to be electrochemically active exhibiting VO V /VO IV quasi-reversible redox couple. The thermal study of the complex yielded VO 2 as sole decomposition product. The coordination compounds 2 and 3 have been isolated from the reaction of complex 1 with 2-cyanopyridine (2-CNPy) and 4-aminobenzonitrile (4-CNAn) respectively and characterized by physicochemical and IR spectral study. The biological activity of 1-3 has been studied against various pathogenic bacteria E. coli, S. aureus, S. typhi, S. paratyphi, S. epidermidis, K. pneumonia and fungi C. albicans, B. fulva, and F. oxysporum by minimum inhibitory concentration (MIC) method. The complexes exhibit enhanced antimicrobial activity relative to both the free ligand and vanadyl sulphate. The cytotoxicity of 1-3 has been studied on mammalian transformed cell line Hep2c, a derivative of human cervix carcinoma HeLa cells by MTT assay. 2 and 3 exhibit higher cytotoxic activity than 1 and reveal a marked effect of the coordination of nitrogen bases.Density functional theory studies have been carried out to determine the relative free energy of formation and stable molecular structures of 1-3. Time dependent density functional theory (TD-DFT) based calculation have been performed to find out the frontier molecular orbitals and to corroborate with the experimentally observed UV-Vis spectrum of 1. Other parameters like HOMO, and LUMO energies, density of state (DOS), and global reactivity descriptors clearly support higher biological activity of 2 and 3 than 1.

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Optical properties of vanadium dioxide nanoparticles in nanoporous glasses

Cited by 6 publications

References 6 publications

Light dynamics in glass-vanadium dioxide nanocomposite waveguides with thermal nonlinearity

Light dynamics in glass-vanadium dioxide nanocomposite waveguides with thermal nonlinearity

Optical properties of vanadium dioxide thin film in nanoparticle structure

Vanadium(IV) coordination complexes with excellent biological activities: a synthetic, characterization, and density functional theory approach

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