Study of Fluorine-Doped TiO2 Sol-Gel Thin Coatings

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
T. Giannakopoulou ◽  
N. Todorova ◽  
T. Vaimakis ◽  
S. Ladas ◽  
C. Trapalis
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Absorption Edge ◽  
Dispersion Model ◽  
Sol Gel ◽  
Linear Part ◽  
Visible Region ◽  
Soda Lime Glass ◽  
Tio2 Thin Films ◽  
X Ray

Ti O 2 is an excellent material for degradation of many environmental contaminants. Its photocatalytic activity is restricted by UV spectral region that can be extended to visible region using different doping techniques. Effect of fluorine-doping on the optical properties of sol-gel prepared TiO2 thin films is reported. Trifluoroacetic acid (CF3COOH) was used as fluorine source with starting concentrations of 5at.%, 10at.%, and 20at.% F to Ti. Gel films were deposited on SiO2∕soda lime glass substrates by dip-coating technique. After thermal treatment at 450°C fluorine containing TiO2 thin films were obtained. The crystallinity of the films was determined by X-ray diffraction (XRD). The X-ray photoemission spectrometry (XPS) was applied to determine valence state of the dopant and bonding element. The optical constants, namely, refractive index and the extinction coefficient, were obtained by fitting UV-visible theoretical transmittance curves to experimental ones. The simulated transmittance was calculated in the frames of the Forouhi–Bloomer (FB) dispersion model. The values of the FB energy band gap determined as onset of the absorption were compared with Tauc band gap values received by extrapolation of the linear part of the absorption edge. The XRD patterns reflect beginning of the anatase crystallization process. The XPS analysis reveals the presence of fluorine in the films in the form of titanium fluoride, titanium oxyfluorides, and nonstoichiometric TiO2−xFx. The linear part of the absorption edge of TiO2 films for mentioned fluorine concentrations gives slightly increased values of Tauc band gap (∼3.7eV) than that for bulk TiO2(∼3.2eV). Also, its broadening at lower frequencies with a FB band gap ∼2.7eV is observed. The results show that, although the fluorine is incorporated in the TiO2 lattice, it does not affect the crystallinity and band gap of the formed TiO2 film for the F∕Ti ratios used in the starting sols.

scholarly journals Microstructure Evolution of Ag/TiO2 Thin Film

2021 ◽  
Vol 7 (1) ◽  
pp. 14
Author(s):  
Dewi Suriyani Che Halin ◽  
Kamrosni Abdul Razak ◽  
Mohd Arif Anuar Mohd Salleh ◽  
Mohd Izrul Izwan Ramli ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Growth Rate ◽  
Synchrotron Radiation ◽  
Tio2 Thin Film ◽  
Sol Gel ◽  
Tio2 Thin Films ◽  
Contact Mode ◽  
X Ray ◽  
Radiation Imaging

Ag/TiO2 thin films were prepared using the sol-gel spin coating method. The microstructural growth behaviors of the prepared Ag/TiO2 thin films were elucidated using real-time synchrotron radiation imaging, its structure was determined using grazing incidence X-ray diffraction (GIXRD), its morphology was imaged using the field emission scanning electron microscopy (FESEM), and its surface topography was examined using the atomic force microscope (AFM) in contact mode. The cubical shape was detected and identified as Ag, while the anatase, TiO2 thin film resembled a porous ring-like structure. It was found that each ring that coalesced and formed channels occurred at a low annealing temperature of 280 °C. The energy dispersive X-ray (EDX) result revealed a small amount of Ag presence in the Ag/TiO2 thin films. From the in-situ synchrotron radiation imaging, it was observed that as the annealing time increased, the growth of Ag/TiO2 also increased in terms of area and the number of junctions. The growth rate of Ag/TiO2 at 600 s was 47.26 µm2/s, and after 1200 s it decreased to 11.50 µm2/s and 11.55 µm2/s at 1800 s. Prolonged annealing will further decrease the growth rate to 5.94 µm2/s, 4.12 µm2/s and 4.86 µm2/s at 2400 s, 3000 s and 3600 s, respectively.

Preparation and characterization of V2O5 doped SiO2-TiO2 thin films

2012 ◽  
Vol 2 (1) ◽  
Author(s):  
Marek Nocuń ◽  
Sławomir Kwaśny
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Dip Coating ◽  
Band Gap Energy ◽  
Tio2 Thin Films ◽  
Glass Substrates ◽  
Gel Technique

AbstractIn our investigation, V doped SiO2/TiO2 thin films were prepared on glass substrates by dip coating sol-gel technique. Chemical composition of the samples was studied by X-ray photoelectron spectroscopy (XPS). Transmittance of the samples was characterized using UV-VIS spectrophotometry. Subsequently band-gap energy (Eg) was estimated for these films. Powders obtained from sols were characterized by FTIR spectroscopy. It was found that vanadium decreases optical band gap of SSiO2/TiO2 films.

A Study on the Preparation of TiO2-xNx Films by Reactive Deposition and Their Absorption Properties in Visible Region

2005 ◽  
Vol 475-479 ◽  
pp. 1223-1226 ◽  
Author(s):  
Ming Zhao ◽  
Da Ming Zhuang ◽  
Gong Zhang ◽  
Ling Fang ◽  
Min Sheng Wu
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Absorption Edge ◽  
Visible Region ◽  
Reactive Magnetron Sputtering ◽  
Tio2 Films ◽  
Reactive Magnetron ◽  
Tio2 Thin Films ◽  
Doped Tio2 ◽  
Nitrogen Doped

The nitrogen-doped TiO2 thin films were prepared by mid-frequency alternative reactive magnetron sputtering technique. The N concentration of the nitrogen-doped TiO2 thin films was analyzed by XPS. And the absorption spectra of the films in ultraviolet and visible region were also investigated. The results show that the mid-frequency alternative reactive magnetron sputtering technique is a convenient method for growing TiO2-xNx. Annealing the nitrogen-doped TiO2 thin film in nitrogen atmosphere under 380°C is helpful for increase the concentration of nitrogen in the film, but the ratio of N2 in reactive gas is mainly influence the concentration of nitrogen in the Ti-N bond in the TiO2 film. The increase of the thickness of nitrogen-doped TiO2 films will enhance the absorbability of the film in the ultraviolet and visible region. The wavelength of the absorption edge of TiO2-xNx film with 1.5% nitrogen shift to 441nm from 387nm, which is the absorption edge for undoped TiO2 films.

scholarly journals Growth of Zn1−x CdxO nanocrystalline thin films by sol-gel method and their characterization for optoelectronic applications

2014 ◽  
Vol 32 (4) ◽  
pp. 688-695 ◽  
Author(s):  
Munirah Munirah ◽  
Ziaul Khan ◽  
Mohd. Khan ◽  
Anver Aziz
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Visible Region ◽  
Zno Thin Films ◽  
Band Edge Emission ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cd Doping ◽  
Vis Spectroscopy ◽  
Doped Zno

AbstractThis paper describes the growth of Cd doped ZnO thin films on a glass substrate via sol-gel spin coating technique. The effect of Cd doping on ZnO thin films was investigated using X-ray diffraction (XRD), UV-Vis spectroscopy, photoluminescence spectroscopy, I–V characteristics and field emission scanning electron microscopy (FESEM). X-ray diffraction patterns showed that the films have preferred orientation along (002) plane with hexagonal wurtzite structure. The average crystallite sizes decreased from 24 nm to 9 nm, upon increasing of Cd doping. The films transmittance was found to be very high (92 to 95 %) in the visible region of solar spectrum. The optical band gap of ZnO and Cd doped ZnO thin films was calculated using the transmittance spectra and was found to be in the range of 3.30 to 2.77 eV. On increasing Cd concentration in ZnO binary system, the absorption edge of the films showed the red shifting. Photoluminescence spectra of the films showed the characteristic band edge emission centred over 377 to 448 nm. Electrical characterization revealed that the films had semiconducting and light sensitive behaviour.

STUDIES ON THE TiO2 THIN FILMS DOPED WITH Fe3+

2005 ◽  
Vol 19 (01n03) ◽  
pp. 671-673
Author(s):  
PENG XIAO ◽  
WANLU WANG
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Electrical Properties ◽  
Sol Gel ◽  
Experimental Results ◽  
X Ray Diffraction ◽  
Tio2 Thin Films ◽  
Gel Method ◽  
X Ray ◽  
Nanometer Particles

The Fe 3+- TiO 2 thin films obtained through sol-gel method were characterized by x-ray diffraction, AFM and Raman spectroscopy. It was found that TiO 2 films consisted of nanometer particles. The experimental results shows that the nanometer TiO 2 thin films doped with Fe 3+ were greatly improved in the activity aspect. This may be ascribed to change their structure and electrical properties after doping with Fe 3+. The results were discussed theoretically in detail.

scholarly journals Enhanced Visible Light Photocatalytic Activity of Mesoporous AnataseTiO2Codoped with Nitrogen and Chlorine

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Xiuwen Cheng ◽  
Xiujuan Yu ◽  
Zipeng Xing ◽  
Lisha Yang
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Band Gap ◽  
Light Absorption ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Visible Region ◽  
X Ray ◽  
Visible Light Photocatalytic Activity ◽  
Visible Light Photocatalytic

Anatase mesoporous titanium dioxide codoped with nitrogen and chlorine (N-Cl-TiO2) photocatalysts were synthesized through simple one-step sol-gel reactions in the presence of ammonium chloride. The resulting materials were characterized by X-ray diffraction (XRD), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet-visible diffuse reflection spectrum (UV-vis DRS). XRD results indicated that codoping with nitrogen and chlorine could effectively retard the phase transformation of TiO2from anatase to rutile and the growth of the crystallite sizes. XPS revealed that nitrogen and chlorine elements were incorporated into the lattice of TiO2through substituting the lattice oxygen atoms. DRS exhibited that the light absorption of N-Cl-TiO2in visible region was greatly improved. As a result, the band gap of TiO2was reduced to 2.12 eV. The photocatalytic activity of the as-synthesized TiO2was evaluated for the degradation of RhB and phenol under visible light irradiation. It was found that N-Cl-TiO2catalyst exhibited higher visible light photocatalytic activity than that of P25 TiO2and N-TiO2, which was attributed to the small crystallite size, intense light absorption in visible region, and narrow band gap.

scholarly journals Boron-doped TiO2 (B-TiO2) Thin Films Grown Using Sol-Gel Spin Coating Method

2018 ◽  
pp. 1-17
Author(s):  
D. O. Samson ◽  
A. D. A. Buba
Keyword(s):  
Thin Films ◽  
Wavelength Range ◽  
Doping Concentration ◽  
Sol Gel ◽  
Visible Region ◽  
Boron Doping ◽  
Pure Tio2 ◽  
Visible Range ◽  
Ultraviolet Region ◽  
Tio2 Thin Films

In this study, the effect of modifying boron doping concentration on the optical properties, electrical properties and microstructural images of TiO2 thin films was investigated by the sol-gel technique by grinding TiO2 powder with a boron compound at a wavelength range of 250 nm to 850 nm. The SEM micro-images revealed the homogenous, continuous and nanocrystalline surface morphology: 10% is the tolerable amount of boron doping concentration into the TiO2 for achieving sphere-like nanostructures materials with low agglomeration. The XRD spectra of the B-TiO2 films showed anatase peaks of greater intensities when compared to the pure TiO2 film. All the films illustrate extinction coefficient in the visible region of solar spectra corresponding to the low absorption, and absorption peaks established in the ultraviolet region near 330nm with the optical transmittance varied from over 52 - 96% in the UV-Vis wavelength range. Diffuse reflectance absorption spectra analysis indicated that the incorporation of B into TiO2 material results in a substantial red shift and the absorption extends significantly into the visible range. The optical band gap energy values of the thin films were found to be 3.38, 3.35, 3.28, 3.26, and 3.36eV. This showed a low probability of raising the electron across the mobility gap with the photon energy in the visible region. The refractive index values varied between 1.891 and 1.922 depending on the percentage content of boron. Moreover, the imaginary part of the dielectric constant increase slowly, whereas the real part increases sharply and the optical conductivity was found to increase with the increase in boron addition.  

Correlation of Thickness with the Photocatalytic Characteristic of TiO2 Thin Films

2005 ◽  
Vol 486-487 ◽  
pp. 65-68 ◽  
Author(s):  
Sang Wook Lee ◽  
Hyun Suk Jung ◽  
Dong Wook Kim ◽  
Kug Sun Hong
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Stearic Acid ◽  
Band Gap ◽  
Uv Light ◽  
Sol Gel ◽  
Photocatalytic Property ◽  
Tio2 Films ◽  
Tio2 Thin Films ◽  
Sol Gel Process

5, 10, and 30 nm thickness of transparent TiO2 thin films were fabricated using sol-gel process, and the influence of film thickness on the photocatalytic property was investigated. The increase in film thickness was found to enhance the photocatalytic property of the films. Photocatalytic properties of each film were estimated by decomposition of stearic acid. The amount of decomposed stearic acid increased with film thickness (5 - 30 nm). For the case of 30 nm thickness film, the stearic acid was decomposed perfectly in twelve minutes. UV-vis spectra and photocurrents of each film clearly showed that the photoactivities of TiO2 films were related to the amount of absorbed UV light and band gap shift.

scholarly journals Structural, Chemical and Optical Properties of Pure and Al-Doped Zno Thin Films Derived by Sol–Gel Dip Coating Process

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ali sadek Kadari ◽  
Abdelkader Nebatti Ech-Chergui ◽  
Mohamed walid Mohamedi ◽  
Abdelhalim Zoukel ◽  
Tair Sabrina ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Sol Gel ◽  
Visible Region ◽  
Dip Coating ◽  
Band Gap Energy ◽  
Sem Analysis ◽  
Zno Thin Films ◽  
X Ray ◽  
Doped Zno

Abstract Pure and Al-doped ZnO thin films were successfully deposited with sol-gel dip coating on both substrates Si (100) and glass. The structural, chemical, morphological and optical properties as a function of the annealing temperature and dopant atomic concentration were investigated by means of X-ray diffraction, Energy dispersive X-ray, Scanning Electron Microscopy, and spectrophotometry. All the pure and doped films show a polycrystalline nature and hexagonal in structure. Accurate doping was proven by EDX. In addition, the SEM analysis revealed that the films possess uniform distribution throughout the surface and the grain dimension decreases with Al doping. From the transmittance measurements, it is see that all films are over 55% in the visible region and the band gap energy increases from 3.28 to 3.45 eV with the increase of Al concentration.

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