Optical Characterization of Laser-Synthesized Anatase TiO<sub>2</sub>Nanopowders by Spectroscopic Ellipsometry and Photoluminescence Measurements

Šćepanović, M.; Mirić, M.; Dohčević‐Mitrović, Z.; Popović, Zoran V.

doi:10.12693/aphyspola.116.603

Cited by 7 publications

(3 citation statements)

References 23 publications

(35 reference statements)

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“…The UV-Vis absorption spectra of these samples in Figure 3(a) account for the corresponding colors. From the Tauc plot of the absorption spectrum of MTF in Figure 3(b), its band gap energy is calculated to be 3.3 eV, slightly larger than that of anatase (3.2 eV), 25,26 probably because of the thin titania walls of MTF, ~4 nm. The Tauc plots of R-MTFs show that the original band gap of TiO 2 is practically unaffected by the reduction.…”

Section: 22mentioning

confidence: 98%

Reduced Titania Films with Ordered Nanopores and Their Application to Visible Light Water Splitting

Shahid¹,

Choi²,

Liu³

et al. 2013

Bulletin of the Korean Chemical Society

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We report on the photoelectrochemical properties of partially reduced mesoporous titania thin films. The fabrication is achieved by synthesizing mesoporous titania thin films through the self-assembly of a titania precursor and a block copolymer, followed by aging and calcination, and heat-treatment under a H 2 (1 torr) environment. Depending on the temperature used for the reaction with H 2 , the degree of the reduction (generation of oxygen vacancies) of the titania is controlled. The oxygen vacancies induce visible light absorption, and decrease of resistance while the mesoporosity is practically unaltered. The photoelectrochemical activity data on these films, by measuring their photocurrent-potential behavior in 1 M NaOH electrolyte under AM 1.5G 100 mW cm −2 illumination, show that the three effects of the oxygen vacancies contribute to the enhancement of the photoelectrochemical properties of the mesoporous titania thin films. The results show that these oxygen deficient TiO 2 mesoporous thin films hold great promise for a solar hydrogen generation. Suggestions for the materials design for improved photoelectrochemical properties are made.

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Section: 22mentioning

confidence: 98%

Reduced Titania Films with Ordered Nanopores and Their Application to Visible Light Water Splitting

Shahid¹,

Choi²,

Liu³

et al. 2013

Bulletin of the Korean Chemical Society

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“…Titanium dioxide is one of the metal oxide semiconductors that have been widely examined for different purposes, since its physical and chemical properties show remarkable changes when the size of the TiO 2 approaches nm scale [4][5][6]. The modification of TiO 2 by means of metal doping can also affect the properties of TiO 2 .…”

Section: Introductionmentioning

confidence: 99%

Characterization of Ag-TiO₂Powders Prepared by Sol-Gel Process

et al. 2017

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In this study, microstructure and electrical properties of Ag-TiO2 powders, which were prepared by a simple sol-gel method, are investigated. The sol was prepared from titanium iso-propoxide, Ti(OC3H7)4 in iso-propanol (CH3CHOHCH3), used as solvent. AgNO3 was used as the precursor for Ag. For the structural studies, the corresponding gels were allowed to dry naturally for about seven days, dried in an oven at 180• C for 30 min and then calcined at different temperatures (900, 1000 and 1100• C). The Ag-TiO2 nanoparticles were characterized using differential thermal analysis/thermal gravimetry, scanning electron microscopy, energy-dispersive X-ray analysis and X-ray diffraction. The results X-ray diffraction indicate that pure Ag and TiO2 powders are in rutile phase. However, calcination temperature had not significantly affected the crystalline structure of TiO2. Scanning electron microscopy images of powders show an aggregation of small spherical particles of dispersed sizes. Annealing of the Ag-TiO2 sample at high temperature produced more spherical particles, which aggregated to form bigger particles with porous structures. The electrical properties of the samples were measured using HMS-3000 Hall measurement system. The samples were found to be of n-type. IntroductionTitanium dioxide (TiO 2 ) has attracted interest due to such advantages, as effectiveness, chemical stability, nontoxicity, and relatively low cost, strong resistance to the chemical and photo-corrosion, low operational temperature, antibacterial properties and low energy consumption [1][2][3]. Titanium dioxide is one of the metal oxide semiconductors that have been widely examined for different purposes, since its physical and chemical properties show remarkable changes when the size of the TiO 2 approaches nm scale [4][5][6]. The modification of TiO 2 by means of metal doping can also affect the properties of TiO 2 . Silver, among the other metals, thanks to its high stability and excellent electrical and thermal conductivity, seems to be a favourable titania dopant [7,8]. In recent years, many researchers have investigated the effect of Ag nanoparticles on properties of TiO 2 [9][10][11][12][13][14][15]. Sol-gel is a low temperature, chemical solution method [16][17][18], which is a proven conventional method for preparation of composite Ag-TiO 2 compound.In this work, we have prepared nanosized TiO 2 and Ag-TiO 2 powders by sol-gel process, using titanium iso-propoxide and silver nitrate as precursors and isopropanol as solvent. The effects of Ag on the morphology, crystallization and phase transition of TiO 2 nanoparticles were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and differential thermal analysis (DTA) techniques.

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“…Among the semiconductor nanoparticles, TiO 2 is a significant band gap n-type material, with a band gap of 3.2, 3.0 and 3.3 eV for the anatase, rutile, and brookite phases, respectively [1][2][3][4]. Rutile phase of TiO 2 is more stable than the other two phases and the transformation from anatase and brookite to rutile can be achieved by thermal annealing [5][6][7]. Nanosized TiO 2 has found applications in many fields like gas sensors [8,9] transistors [10], light-emitting diodes (LED) [11], sunscreen [12], field emission devices [13] and solar cells [14].…”

Section: Introductionmentioning

confidence: 99%

Influence of thermal annealing on the photo catalytic properties of TiO2 nanoparticles under solar irradiation

Prasannalakshmi

Shanmugam

Kannadasan

et al. 2015

J Mater Sci: Mater Electron

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Nanosized TiO 2 particles have been synthesized by a sol-gel method and studied for their thermal, structural, optical, morphological, and photocatalytic properties at different annealed temperatures. The results of the structural analysis show the anatase phase of TiO 2 at 400°C, the mixed phase at 700°C, and pure rutile phase at 800°C. The red-shift of absorption edges and band gap reduction are the two factors suggested by UV-Vis spectra, confirming the phase change of TiO 2 from anatase to rutile on annealing at 800°C. The PL emission results of annealed products exhibit enhanced visible emissions on annealing as a result of increased oxygen vacancies. The photocatalytic activities of the annealed products were analyzed against the organic dye brilliant green (BG). Among the all, TiO 2 annealed at 700°C shows an enhanced photocatalytic performance against the organic dye BG.

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Optical Characterization of Laser-Synthesized Anatase TiO₂Nanopowders by Spectroscopic Ellipsometry and Photoluminescence Measurements

Cited by 7 publications

References 23 publications

Reduced Titania Films with Ordered Nanopores and Their Application to Visible Light Water Splitting

Reduced Titania Films with Ordered Nanopores and Their Application to Visible Light Water Splitting

Characterization of Ag-TiO₂Powders Prepared by Sol-Gel Process

Influence of thermal annealing on the photo catalytic properties of TiO2 nanoparticles under solar irradiation

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Optical Characterization of Laser-Synthesized Anatase TiO2Nanopowders by Spectroscopic Ellipsometry and Photoluminescence Measurements

Cited by 7 publications

References 23 publications

Reduced Titania Films with Ordered Nanopores and Their Application to Visible Light Water Splitting

Reduced Titania Films with Ordered Nanopores and Their Application to Visible Light Water Splitting

Characterization of Ag-TiO2Powders Prepared by Sol-Gel Process

Influence of thermal annealing on the photo catalytic properties of TiO2 nanoparticles under solar irradiation

Contact Info

Product

Resources

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Optical Characterization of Laser-Synthesized Anatase TiO₂Nanopowders by Spectroscopic Ellipsometry and Photoluminescence Measurements

Characterization of Ag-TiO₂Powders Prepared by Sol-Gel Process