The Nanocrystallinity Enhancement and Optical Characteristics of Pre-Hydrothermally Treated ZnO Nanoparticles

In the current research, ZnO nanoparticles have been synthesized via sol-gel technique assisted by a pre-hydrothermal treatment at 150oC with various holding time of 0, 24, 48 and 72 hours. This route was specifically aimed at investigating the effect of this treatment on the nanocrystallite size, crystallinity and band gap energy of the resulting nanoparticles. The results of investigation showed that an increasing of pre-hydrothermal treatment duration from 0 to 72 hours has increased the crystallite size of ZnO nanoparticles from 3.47 to 13.85 nm, and decreased the band gap energy from 3.10 to 3.08 eV.

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FeAl2O4 Nanopowders; Structural Analysis and Band Gap Energy

High Temperature Materials and Processes ◽

10.1515/htmp-2015-0229 ◽

2017 ◽

Vol 36 (8) ◽

pp. 789-793 ◽

Cited By ~ 1

Author(s):

Morteza Enhessari

Keyword(s):

Structural Analysis ◽

Band Gap ◽

Sol Gel ◽

Band Gap Energy ◽

Mixed Metal Oxide ◽

Nanoscale Materials ◽

X Ray Diffraction ◽

Organic Precursor ◽

Gap Energy ◽

Acid Gel

AbstractNanoscale FeAl2O4 was successfully synthesized via sol–gel method. The sol constituents containing iron and aluminum cations were formed homogenously in stearic acid gel (formation of organic precursor). The pure structural analysis and the size of the spinels were confirmed by X-ray diffraction (XRD). It was observed that the size of the nanoscale materials obtained at around 30–40nm. The micrographs of FeAl2O4 evidenced the homogenous and nanosize formation of spinel. The semiconducting behavior of this mixed metal oxide was observed at 3.14eV based on the band gap energy (Eg). The final nanoscale materials exhibited a superparamagnetic behavior with a saturation magnetization of 9.8 emu/g at applied field of 10 kOe.

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Preparation and characterization of V2O5 doped SiO2-TiO2 thin films

Open Engineering ◽

10.2478/s13531-011-0041-6 ◽

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.

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Effect of ZnO on a Superhydrophilic Self-Cleaning Properties of TiO2/SiO2 Thin Film on Glass Slide Substrate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1131.237 ◽

2015 ◽

Vol 1131 ◽

pp. 237-241 ◽

Cited By ~ 1

Author(s):

Akkarat Wongkaew ◽

Chanida Soontornkallapaki ◽

Naritsara Amhae ◽

Wichet Lamai

Keyword(s):

Thin Film ◽

Contact Angle ◽

Visible Light ◽

Band Gap ◽

Sol Gel ◽

Dip Coating ◽

Band Gap Energy ◽

Gap Energy ◽

Coating Method ◽

Dip Coating Method

This work aims to study the effect of ZnO containing in TiO2/SiO2 film on the superhydrophilic property after exposed to different types of light. The metal solutions were prepared by sol-gel technique and the film was deposited on glass slides by dip coating method. The parameter studied was the amount of ZnO in the TiO2/SiO2 film. The contents of ZnO were 5-20% weight (increased by 5%). The amount of TiO2 was constant at 30% weight. The obtained films were analyzed for their roughness. The results indicated that film roughness changed according to the ZnO contents. With 5%ZnO in the thin film, the roughness was 0.726 nm while 20%ZnO obtained the roughness of 2.128 nm. UV-Vis spectrophotometer was used for measuring of transmittance of films. At wavelength of 550 nm, the transmittances of each film were greater than 90%. Band gap energy of each film was calculated from the transmittance data. It was found that the average band gap energy of the films was 2.47 eV. Then, the films contained various amount of ZnO were grouped into 2 sets. The first set was exposed to visible light while the other set was exposed to UV. The duration of exposure was 5 hr. Both sets of films after exposed to any light were kept in a black box controlled relative humidity of 85%. Each film was measured contact angle every day. It was found that the 30%TiO2/5%Zn/SiO2 film exposed to visible light showed the best superhydrophilic property. The contact angle was about 0-5° within 3 days. This may due to the reduction of band gap energy in the presence of ZnO in TiO2/SiO2 films to 2.41 eV and the roughness of the film.

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A correlation for crystallite size of undoped ZnO thin film with the band gap energy – precursor molarity – substrate temperature

Optik ◽

10.1016/j.ijleo.2013.08.015 ◽

2014 ◽

Vol 125 (3) ◽

pp. 1303-1306 ◽

Cited By ~ 23

Author(s):

Said Benramache ◽

Okba Belahssen ◽

Ali Arif ◽

Abderrazak Guettaf

Keyword(s):

Thin Film ◽

Substrate Temperature ◽

Band Gap ◽

Crystallite Size ◽

Band Gap Energy ◽

Zno Thin Film ◽

Gap Energy

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N-Loaded TiO2 for Photocatalytic Degradation of Methyl Orange under Visible Light Irradiation

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.622-623.883 ◽

2012 ◽

Vol 622-623 ◽

pp. 883-888

Author(s):

Natkritta Boonprakob ◽

Natda Wetchakun ◽

Sukon Phanichphant ◽

Jun Chen ◽

Burapat Inceesungvorn

Keyword(s):

Methyl Orange ◽

Visible Light ◽

Band Gap ◽

Visible Light Irradiation ◽

Sol Gel ◽

Band Gap Energy ◽

Light Irradiation ◽

Gap Energy ◽

Visible Light Driven ◽

Degradation Of Methyl Orange

Nitrogen-loaded TiO2(N-loaded TiO2), a visible-light driven catalyst, was successfully synthesized by the modified sol-gel method. Physical characterizations of the as-prepared catalysts have been performed by using X-ray diffraction (XRD), Diffuse reflectance UVvisspectroscopy(DRUVvis), Raman spectroscopyand BETspecific surface areain order to obtain structure-activity relationship. Results from Raman spectroscopy clearly suggested that N atoms were incorporated into the TiO2crystal lattice as evidenced by the vibrational peak of TiN in TiO2-xNx.DR UVvis results also suggested that the nitrogen dopant might be responsible for narrowing the TiO2band gap energy, thus resulting in a shift towards the visiblelight region. Photocatalytic activity of N-loaded TiO2evaluated through the degradation of methyl orange (MO)under visible light irradiation (l> 400 nm) indicated that all N-loaded photocatalysts exhibited significantly higher activities than the unloaded TiO2and Degussa P25 TiO2. According to the results from DR UV-vis, XRD and BET studies, the enhanced photoactivity observed from N-loaded samples might be due to a decrease in TiO2band gap energy and/or changes in chemical and physical properties of the materials upon loading with nitrogen.

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Effect of Li Substitution in MgO Nanostructured on Band Gap Energy via Combustion Synthesis Method

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.301.97 ◽

2020 ◽

Vol 301 ◽

pp. 97-102

Author(s):

Nor Fadilah Chayed ◽

Nurhanna Badar ◽

Kelimah Elong ◽

Norlida Kamarulzaman

Keyword(s):

Band Gap ◽

Crystallite Size ◽

Synthesis Method ◽

Combustion Method ◽

Band Gap Energy ◽

X Ray Diffraction ◽

Gap Energy ◽

Polyhedral Shape ◽

Band Gap Narrowing ◽

Li Substitution

Preparation of MgO and Mg0.9Li0.2O materials using self-propagating combustion method are done to investigate the effect of substitution doping on the band gap energy. The synthesis condition has been optimized to obtain pure and single phase of MgO and Mg0.9Li0.2O materials and was confirmed by X-Ray Diffraction (XRD). The morphology obtained from field emission scanning electron microscopy (FESEM) is spherical and rounded polyhedral shape with agglomeration of crystallites for MgO and Mg0.9Li0.2O materials respectively. The crystallite size of MgO and Mg0.9 Li0.2O samples is between 50 nm to 120 nm and 200 nm to 1500 nm respectively. The band gap was determined by UV-Vis NIR spectrophotometer and it was found that the band gap obtained for MgO nanostructure is 6.10 eV which is lower than bulk MgO of 7.8 eV. The presence of Li in the MgO had caused changes in morphology, crystallite size and band gap narrowing to 3.83 eV.

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Electrical, dielectric and photocatalytic properties of Fe-doped ZnO nanomaterials synthesized by sol gel method

Processing and Application of Ceramics ◽

10.2298/pac1603125c ◽

2016 ◽

Vol 10 (3) ◽

pp. 125-135 ◽

Cited By ~ 22

Author(s):

Yacine Cherifi ◽

Ahcène Chaouchi ◽

Yannick Lorgoilloux ◽

Mohammed Rguiti ◽

Abdelaziz Kadri ◽

...

Keyword(s):

Single Phase ◽

Uv Light ◽

Sol Gel ◽

Complex Impedance ◽

Hexagonal Wurtzite Structure ◽

Band Gap Energy ◽

Cbh Model ◽

Gap Energy ◽

Gel Technique ◽

Doped Zno

Fe-doped ZnO nanoparticles were synthesized by sol gel technique. Fine-scale and single phase hexagonal wurtzite structure in all samples were confirmed by SEM and XRD, respectively. The band gap energy depends on the amount of Fe and was found to be in the range of 3.11-2.53 eV. The electric and dielectric properties were investigated using complex impedance spectroscopy. AC conductivity data were correlated with the barrier hopping (CBH) model to evaluate the binding energy (Wm), the minimum hopping distance (Rmin) and the density of states at Fermi level, N(EF). Fe doping in ZnO also improved the photocatalytic activity. Thus, the sample Zn0.95Fe0.05O showed high degradation potential towards methylene blue (MB), i.e. it degrades 90% of BM in 90min under UV light.

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