共查询到20条相似文献,搜索用时 15 毫秒
1.
Zineb Essalhi Bouchaib Hartiti Abderrazak Lfakir Bernabé Mari Philippe Thevenin 《Optical and Quantum Electronics》2017,49(9):301
In this research, Cu-doped TiO2 thin films have been successfully deposited onto a glass substrate by Sol–gel technique using dip coating method. The films were annealed at different annealing temperatures (400–500 °C) for 1 h. The structural, optical and electrical properties of the films were investigated and compared using X-ray Diffraction, UV–visible spectrophotometer and 4-point probe method. Optical analysis by mean transmittance T(λ) and absorption A(λ) measurements in the wavelength range between 300 to 800 nm allow us to determine the indirect band gap energy. DRX analysis of our thin films of TiO2:Cu shows that the intensities of the line characteristic of anatase phase increasing in function of the temperature. 相似文献
2.
Y.C. Wu C. Garapon R. Bazzi A. Pillonnet O. Tillement J. Mugnier 《Applied Physics A: Materials Science & Processing》2007,87(4):697-704
Terbium doped Y2O3 planar waveguides were fabricated by sol–gel process and dip-coating using yttrium acetate as precursor. Two different doping
modes were compared, i.e. introduction in the sol of dispersed Tb3+ions from dissolved Tb(NO3)3, or of nanoparticles of Tb2O3 or [Y2O3:50% Tb] from an alcoholic suspension. The chemical and nanostructural properties were analyzed by infrared spectroscopy,
transmission electron microscopy and X-ray diffraction. The Tb3+ fluorescence properties were studied as a function of temperature and atmosphere of the thermal treatments, and of the Tb3+ concentration. The fluorescence properties are discussed in relation to the quenching mechanisms induced by Tb4+ transformation, residual OH groups, and crystallites size and structure. Optical propagation losses of the Tb doped Y2O3 planar waveguides related to the doping modes and Tb3+ concentration are presented. Doping sol–gel films by nanoparticles is shown to be a valuable alternative to the conventional
doping from dissolved terbium salt.
PACS 81.21.Fw; 84.40.Az; 78.67.Bf 相似文献
3.
TiO2 Nano rods can be used as dye-sensitized solar cells, various sensors and photocatalysts. These nanorods are synthesized by
a hydrothermal corrosion process in NaOH solution at 200°C using TiO2 powder as the source material. In the present work, the synthesis of TiO2 nanorods in anatase, rutile and Ti7O13 phases and synthesis of TiO2 nanorods by incorporating SiO2 dopant, using the sol–gel method and alkaline corrosion are reported. The morphologies and crystal structures of the TiO2 nanorods are characterized using field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM) and
X-ray diffraction (XRD) study. The obtained results show not only an aggregation structure at high calcination temperatures
with spherical particles but also Ti–O–Si bonds having four-fold coordination with oxygen in SiO4 − . 相似文献
4.
Damian Wojcieszak Danuta Kaczmarek Jaroslaw Domaradzki Eugeniusz L. Prociow Antoni W. Morawski Magdalena Janus 《Central European Journal of Physics》2011,9(2):354-359
In this work photocatalytic properties of TiO2 thin films doped with different amount of Tb have been described. Thin films were prepared by high energy reactive magnetron
sputtering process. Comparable photocatalytic activity has been found for all doped TiO2 thin films, while different amounts of Tb dopant (0.4 and 2.6 at. %) results in either an anatase or rutile structure. It
was found that the terbium dopant incorporated into TiO2 was also responsible for the amount of hydroxyl groups and water particles adsorbed on the thin film surfaces and thus photocatalytic
activity was few times higher in comparison with results collected for undoped TiO2 thin films. 相似文献
5.
The oriented ZnO nanorod arrays have been synthesized on a silicon wafer that coated with TiO2 films by aqueous chemical method. The morphologies, phase structure and the photoluminescence (PL) properties of the as-obtained
product were investigated by field-emission scanning electron microscopy (FE-SEM), X-ray diffractometer (XRD), transmission
electron microscope (TEM) and PL spectrum. The nanorods were about 100 nm in diameter and more than 1 μm in length, which
possessed wurtzite structure with a c axis growth direction. The room-temperature PL measurement of the nanorod arrays showed strong ultraviolet emission. The
effect of the crystal structure and the thickness of TiO2 films on the morphologies of ZnO nanostructures were investigated. It was found that the rutile TiO2 films were appropriate to the oriented growth of ZnO nanorod arrays in comparison with anatase TiO2 films. Moreover, flakelike ZnO nanostructures were obtained with increasing the thickness of anatase TiO2 films. 相似文献
6.
T. V. Sviridova L. Yu. Sadovskaya A. I. Kokorin E. A. Konstantinova V. E. Agabekov D. V. Sviridov 《Russian Journal of Physical Chemistry B, Focus on Physics》2017,11(2):348-353
The thin-film photocatalysts TiO2/MoO3 and TiO2/MoO3:V2O5 obtained by a combination of sol–gel and sintering techniques were studied using the photooxidation of probing dyes, EPR spectroscopy, X-ray diffraction analysis, and electron microscopy. It was shown that due to charge accumulation caused by UV irradiation, these photocatalysts retain their oxidative activity and ability for self-sterilization in the dark for a long time after irradiation was terminated (up to 5 h for TiO2/MoO3:V2O5). 相似文献
7.
Hao Cheng Xiujian Zhao Xiaotao Sui Yuli Xiong Jiang Zhao 《Journal of nanoparticle research》2011,13(2):555-562
CdS quantum dot (Qd)-sensitized TiO2 nanotube array photoelectrode is synthesised via a two-step method on tin-doped In2O3-coated (ITO) glass substrate. TiO2 nanotube arrays are prepared in the ethylene glycol electrolyte solution by anodizing titanium films which are deposited
on ITO glass substrate by radio frequency sputtering. Then, the CdS Qds are deposited on the nanotubes by successive ionic
layer adsorption and reaction technique. The resulting nanotube arrays are characterized by scanning electron microscopy,
X-ray diffraction (XRD) and UV–visible absorption spectroscopy. The length of the obtained nanotubes reaches 1.60 μm and their
inner diameter and wall thickness are around 90 and 20 nm, respectively. The XRD results show that the as-prepared TiO2 nanotubes array is amorphous, which are converted to anatase TiO2 after annealed at 450 °C for 2 h. The CdS Qds deposited on the TiO2 nanotubes shift the absorption edge of TiO2 from 388 to 494 nm. The results show that the CdS-sensitized TiO2 nanotubes array film can be used as the photoelectrode for solar cells. 相似文献
8.
G. Valverde-Aguilar J. A. García-Macedo V. Rentería-Tapia M. Aguilar-Franco 《Applied Physics A: Materials Science & Processing》2011,103(3):659-663
In this work, amorphous and crystalline TiO2 films were synthesized by the sol–gel process at room temperature. The TiO2 films were doped with gold nanoparticles. The films were spin-coated on glass wafers. The crystalline samples were annealed
at 100°C for 30 minutes and sintered at 520°C for 2 h. All films were characterized using X-ray diffraction, transmission
electronic microscopy and UV-Vis absorption spectroscopy. Two crystalline phases, anatase and rutile, were formed in the matrix
TiO2 and TiO2/Au. An absorption peak was located at 570 nm (amorphous) and 645 nm (anatase). Photoconductivity studies were performed on
these films. The experimental data were fitted with straight lines at darkness and under illumination at 515 nm and 645 nm.
This indicates an ohmic behavior. Crystalline TiO2/Au films are more photoconductive than the amorphous ones. 相似文献
9.
Terry A. Egerton Lorna M. Kessell Ian R. Tooley Liwei Wang 《Journal of nanoparticle research》2007,9(2):251-260
Photogreying, the change in brightness on UV irradiation in the absence of oxygen, of TiO2 nanoparticulate dispersions is shown to depend on the nature of the liquid, consistent with a surface reaction. Measurements
on a series of TiO2 particles (mainly 75×10 nm) dispersed in, e.g., alkyl benzoate correlate well with those on the same TiO2’s dispersed in a second liquid (e.g. propan-2-ol). Photogreying in propan-2-ol is paralleled by photocatalytic-oxidation
activity, indicating a common origin – UV-generation of charge carriers. Further, photogreying parallels Ti3+ formation. Hence, although appearance and the visible spectra of photogreyed particles both differ from those of Ti3+ in ≤10 nm colloidal TiO2, we suggest that photogreying is caused by capture of UV excited electrons to form Ti3+. Surface treatment reduces photogreying, and we speculate that differences between uncoated samples reflect differences in
the number of potentially reducible Ti’s. 相似文献
10.
Two sets of samples of SnO2/In2O3/TiO2 system have been fabricated with different concentrations of component materials. In the first set TiO2 with rutile structure was used, while in the second set it has the structure of anatase. Thin films (up to 50 nm) of obtained
mixtures were deposited. Their sensitivity and selectivity with respect to methane (CH4) were studied. Nanostructure on the
basis of 70%SnO2 — 10%In2O3 — 20%TiO2(anatase) exhibits sufficient sensitivity to methane. 相似文献
11.
The controllable synthesis and characterization of novel thermally stable silver-based particles are described. The experimental approach involves the design of thermally stable nanostructures by the deposition of an interfacial thick, active titania layer between the primary substrate (SiO2 particles) and the metal nanoparticles (Ag NPs), as well as the doping of Ag nanoparticles with an organic molecule (Congo Red, CR). The nanostructured particles were composed of a 330-nm silica core capped by a granular titania layer (10 to 13 nm in thickness), along with monodisperse 5 to 30 nm CR-Ag NPs deposited on top. The titania-coated support (SiO2/TiO2 particles) was shown to be chemically and thermally stable and promoted the nucleation and anchoring of CR-Ag NPs, which prevented the sintering of CR-Ag NPs when the structure was exposed to high temperatures. The thermal stability of the silver composites was examined by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Larger than 10 nm CR-Ag NPs were thermally stable up to 300 °C. Such temperature was high enough to destabilize the CR-Ag NPs due to the melting point of the CR. On the other hand, smaller than 10 nm Ag NPs were stable at temperatures up to 500 °C because of the strong metal-metal oxide binding energy. Energy dispersion X-ray spectroscopy (EDS) was carried out to qualitatively analyze the chemical stability of the structure at different temperatures which confirmed the stability of the structure and the existence of silver NPs at temperatures up to 500 °C. 相似文献
12.
Sk.F. Ahmed P.K. Ghosh S. Khan M.K. Mitra K.K. Chattopadhyay 《Applied Physics A: Materials Science & Processing》2007,86(1):139-143
We have observed low-macroscopic field electron emission from wide bandgap nanocrystalline Al doped SnO2 thin films deposited on glass substrates. The emission properties have been studied for different anode-sample spacings and for different Al concentrations in the films. The turn-on field and approximate work function were calculated and we have tried to explain the emission mechanism from this. The turn-on field was found to vary in the range 5.6–7.5 V/μm for a variation of anode sample spacing from 80–120 μm. The turn-on field was also found to vary from 4.6–5.68 V/μm for a fixed anode-sample separation of 80 μm with a variation of Al concentration in the films 8.16–2.31%. The Al concentrations in the films have been measured by energy dispersive X-ray analysis. Optical transmittance measurement of the films showed a high transparency with a direct bandgap ∼3.98 eV. Due to the wide bandgap, the electron affinity of the film decreased. This, along with the nanocrystalline nature of the films, enhanced the field emission properties. PACS 81.20.Fw; 61.10.-i; 79.70.+q 相似文献
13.
Synthesis,characterization of Cr-doped TiO<Subscript>2</Subscript> nanotubes with high photocatalytic activity 总被引:1,自引:0,他引:1
Shoumin Zhang Yanyan Chen Ying Yu Haihong Wu Shurong Wang Baolin Zhu Weiping Huang Shihua Wu 《Journal of nanoparticle research》2008,10(5):871-875
Cr-doped TiO2 nanotubes (Cr/TiO2 NTs) with high photocatalytic activity were prepared by the combination of sol–gel process with hydrothermal treatment. XRD,
TEM and UV–vis DRS techniques were employed for microstructural characterization. TEM images show that Cr/TiO2 NTs are in good tubular structure and have diameter of about 10 nm. The Cr doping induces the shift of the absorption edge
to the visible light range and the narrowing of the band gap. The photocatalytic experiment reveals that the photocatalytic
performance of TiO2 NTs can be improved by the doping of chromium ions. 相似文献
14.
The effect of Fe2O3 in sodium zinc phosphate glass system containing CuO with the chemical composition 40P2O5:38ZnO:1CuO:(21 ? x)Na2O:xFe2O3 (where x = 1, 2, 3, 4, 5 and 6 mol%) has been studied. The glass formability of the prepared samples was examined by means of XRD which proved that there are no natural crystal contents. Archimedes method has been employed to measure the density of the prepared glass samples hence, the molar volume was calculated. The density and the molar volume were found to be increased by increasing Fe2O3 content. The optical spectroscopic analysis for the obtained glass samples has been carried out over the whole range (190–1000 nm) for studying the effect of bandpass absorption glass filter, its color peak center and UV cut-off. The center for bandpass filter is found to exhibit a red shift by increasing Fe2O3 content. Moreover, all glass samples showed a bandstop in UV-range which was increased by increasing Fe2O3 content. The results reveal the practicality of this glass composition in optical color glass bandpass filter for UV preventing applications such as UV-Laser protection. 相似文献
15.
Karolina Sieradzka Danuta Kaczmarek Jarosław Domaradzki Eugeniusz Prociów Michał Mazur Barbara Górnicka 《Central European Journal of Physics》2011,9(2):313-318
Electrical and optical properties of TiO2:Pd thin films deposited from Ti-Pd mosaic targets sputtered in reactive oxygen plasma have been studied. The properties were
investigated for thin films with the Pd amount of 5.5 at. %, 8.4 at. % and 23 at. %. Based on resistivity measurements a drop
from 103 down to almost 10−3Ωcm has been recorded when the Pd amount was varied from 5.5 at. % to 23 at. %, respectively. Moreover, it was shown that
doping with different amounts of Pd results in the possibility of obtaining both types of electrical conduction: n-type for
the TiO2 with 5.5 at. % and 8.4 at. % of Pd and p-type for the TiO2 with 23 at. % of Pd thin films. From optical measurements it has been found that as the Pd amount was increased the transmission
through the thin films was reduced and position of the fundamental absorption edge was shifted toward a longer wavelength
range of up to 600 nm. The optical band gap was calculated for direct and indirect transitions from optical absorption spectra.
Structural properties were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). The XRD patterns displayed
occurrence of the crystalline, TiO2-rutile for lower Pd amounts (5.5 at. %, 8.4 at. %), while the TiO2:Pd (23 at. %) thin films displayed XRD-amorphous behaviour. Images obtained from AFM displayed dense, nanocrystalline structure
with homogenous distribution of crystallites. Additionally performed secondary ion mass spectroscopy investigation confirmed
homogenous distribution of Pd in the whole thickness of the prepared thin films. 相似文献
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19.
V. V. Hoang H. Zung N. H.B. Trong 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(3):515-524
Structural properties of amorphous TiO2 spherical nanoparticles have
been studied in models with different sizes of 2 nm, 3 nm, 4 nm and 5 nm under
non-periodic boundary conditions. We use the pairwise interatomic potentials
proposed by Matsui and Akaogi. Models have been obtained by cooling from the
melt via molecular dynamics (MD) simulation. Structural properties of an
amorphous nanoparticle obtained at 350 K have been analyzed in detail
through the partial radial distribution functions (PRDFs), coordination
number distributions, bond-angle distributions and interatomic distances.
Moreover, we show the radial density profile in a nanoparticle. Calculations
show that size effects on structure of a model are significant and that if
the size is larger than 3 nm, amorphous TiO2 nanoparticles have a
distorted octahedral network structure with the mean coordination number
ZTi-O ≈6.0 and ZO-Ti ≈3.0 like those observed in the
bulk. Surface structure and surface energy of nanoparticles have been
obtained and presented. 相似文献
20.
A. Lakshmi Narayana M. Dhananjaya N. Guru Prakash O. M. Hussain C. M. Julien 《Ionics》2017,23(12):3419-3428
Nanocrystalline Li2TiO3 was successfully synthesized using solid-state reaction method. The microstructural and electrochemical properties of the prepared material are systematically characterized. The X-ray diffraction pattern of the prepared material exhibits predominant (002) orientation related to the monoclinic structure with C2/c space group. HRTEM images and SAED analysis reveal the well-developed nanostructured particles with average size of ~40 nm. The electrochemical properties of the prepared sample are carried out using cyclic voltammetry (CV) and chronopotentiometry (CP) using Pt//Li2TiO3 cell in 1 mol L?1 Li2SO4 aqueous electrolyte. The Li2TiO3 electrode exhibits a specific discharge capacity of 122 mAh g?1; it can be used as anode in Li battery within the potential window 0.0–1.0 V, while investigated as a supercapacitor electrode, it delivers a specific capacitance of 317 F g?1 at a current density of 1 mA g?1 within the potential range ?0.4 to +0.4 V. The demonstration of both anodic and supercapacitor behavior concludes that the nanocrystalline Li2TiO3 is a suitable electrode material for supercapattery application. 相似文献