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

2016 ◽  
Vol 10 (3) ◽  
pp. 125-135 ◽  
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.

NANOCRYSTALLINE ALUMINUM DOPED ZINC OXIDE COATED FIBER OPTIC FOR ULTRAVIOLET DETECTION

2013 ◽  
Vol 22 (03) ◽  
pp. 1350037 ◽  
Author(s):  
A. R. A. RASHID ◽  
P. S. MENON ◽  
S. SHAARI
Keyword(s):  
Refractive Index ◽  
Fiber Optic ◽  
Uv Light ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
Zno Films ◽  
Coated Fiber ◽  
Aluminum Doped Zinc Oxide ◽  
Doped Zno

In this paper, we report the fabrication and characterization of an ultraviolet sensing by using Al -doped ZnO films coated on quartz slide and silica fiber optic. Undoped ZnO , 0.5, 1, 2 and 3 at.% of Al were prepared by sol–gel method with annealing temperature of 400°C for 1 h. The presence of spherical shaped nanoparticles and hexagonal (wurtzite) structure were detected for Al doped ZnO by using FESEM and XRD. The band gap values increased by adding Al due to the increment of carrier concentration. I–V curves reveal an ohmic line and improvement in electrical conductivity when the samples are illuminated by ultraviolet (UV) light with a wavelength of 365 nm. At 1 at.% of Al , the film have a larger increment in photocurrent response when illuminated with UV light compared to undoped ZnO and higher concentration (2 at.% and 3 at.%) of Al . For coated fiber optic, the fiber operates under leaky mode and the refractive index of ZnO is decreasing under UV radiation. There is a small drop in output intensity and increased abruptly which depends on the changes of ZnO refractive index. The thin films have a longer recovery time than response time.

Investigations on Photocatalytic, Antimicrobial and Magnetic Properties of Sol–Gel-Synthesized Ga-Doped ZnO Nanoparticles

2019 ◽  
Vol 18 (01) ◽  
pp. 1850014 ◽  
Author(s):  
Jaskaran Singh Malhotra ◽  
Arnav Sharma ◽  
Arun Kumar Singh ◽  
Sanjeev Kumar ◽  
Bhupendra Singh Rana ◽  
...  
Keyword(s):  
Zno Nanoparticles ◽  
Uv Light ◽  
Sol Gel ◽  
Cost Effective ◽  
Hexagonal Wurtzite Structure ◽  
Weak Ferromagnetism ◽  
Antibacterial Activities ◽  
Blue Dye ◽  
X Ray ◽  
Doped Zno

Gallium (Ga)-doped zinc oxide (ZnO) nanoparticles were synthesized using simple and cost-effective sol–gel method. X-ray powder diffraction studies illustrated the crystalline nature of Ga-doped ZnO nanoparticles with hexagonal wurtzite structure. Fourier-transform infrared spectroscopy and energy dispersive X-ray fluorescence confirmed the Ga[Formula: see text] incorporation in ZnO. The photocatalytic activities of all the synthesized samples were performed on methylene blue dye solution exposed under UV light. The antibacterial activities of the synthesized nanoparticles were investigated against Aeromonas liquefaciens and Shigella flexeneri gram-negative pathogenic strains. The experimental results clearly demonstrated significant enhancement in photocatalytic and antimicrobial activity of ZnO nanoparticles doped with optimum concentration of Ga. Room temperature vibrating sample magnetometer measurements illustrated weak ferromagnetism in all the Ga-doped ZnO samples.

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

2012 ◽  
Vol 557-559 ◽  
pp. 468-471 ◽  
Author(s):  
Akhmad Herman Yuwono ◽  
Ghiska Ramahdita ◽  
Nofrijon Sofyan
Keyword(s):  
Band Gap ◽  
Crystallite Size ◽  
Hydrothermal Treatment ◽  
Zno Nanoparticles ◽  
Treatment Duration ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Nanocrystallite Size ◽  
Gel Technique

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.

scholarly journals Photoelectrochemical characterization and photocatalytic properties of mesoporousTiO2/ZrO2films

2006 ◽  
Vol 2006 ◽  
pp. 1-6 ◽  
Author(s):  
Natalie Smirnova ◽  
Yuriy Gnatyuk ◽  
Anna Eremenko ◽  
Gennadiy Kolbasov ◽  
Vera Vorobetz ◽  
...  
Keyword(s):  
Sol Gel ◽  
Band Gap Energy ◽  
Structural And Optical Properties ◽  
Gap Energy ◽  
Pluronic P123 ◽  
Titania Thin Film ◽  
Photoelectrochemical Characterization ◽  
Vis Spectroscopy ◽  
Gel Technique ◽  
Doped Titania

Optically transparent, crack-free mesoporous titania and zirconia-doped titania thin film photocatalysts were fabricated by sol-gel technique, using nonionic amphiphilic block copolymer Pluronic P123 as template. The structural and optical properties of these films were characterized using SEM, low-angle XRD, and UV/Vis spectroscopy, hexane adsorption investigation. Band gap energy and the position of flatband potentials were estimated by photoelectrochemical measurements. Enhancing of photocatalytic activity of zirconia-doped films relative to pureTiO2originates from an anodic shift of the valence band edge potential. Catalytic activity of mesoporousTiO2andTiO2/ZrO2(5–50% ofZrO2) films in the processes ofCrVItoCrIIIphotoreduction and 2,4-dinitroaniline photooxidation correlates with crystalline size and growth with increasing of specific surface area of the samples.

scholarly journals Structural and optical properties of Fe- doped ZnO thin films prepared by Sol–Gel spin coating process and their photocatalytic activities

2019 ◽  
Vol 17 (40) ◽  
pp. 95-107
Author(s):  
Selma M. H. Al-Jawad
Keyword(s):  
Thin Films ◽  
Organic Dyes ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
Band Gap Energy ◽  
Zno Thin Films ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Doped Zno

Pure and Fe-doped zinc oxide nanocrystalline films were preparedvia a sol–gel method using -C for 2 h.The thin films were prepared and characterized by X-ray diffraction(XRD), atomic force microscopy (AFM), field emission scanningelectron microscopy (FE-SEM) and UV- visible spectroscopy. TheXRD results showed that ZnO has hexagonal wurtzite structure andthe Fe ions were well incorporated into the ZnO structure. As the Felevel increased from 2 wt% to 8 wt%, the crystallite size reduced incomparison with the pure ZnO. The transmittance spectra were thenrecorded at wavelengths ranging from 300 nm to 1000 nm. Theoptical band gap energy of spin-coated films also decreased as Fedoping concentration increased. In particular, their optical band gapenergies were 3.75, 3.6, 3.5, 3.45 and 3.3 eV doping concentration of0%, 2%, 4%, 6% and 8% Fe, respectively. The performance of thepure and doped ZnO thin films was examined for the photocatalyticactivity using organic dyes (methyl orange, methyl blue, methylviolet). The samples ZnO with concentration of Fe showed increasedphotocatalytic activity with an optimal maximum performance at0.8 wt%.

Optical Characterization of Al-doped ZnO Films via Sol-gel Method Using Spectroscopic Ellipsometry

2020 ◽  
Vol 10 (5) ◽  
pp. 642-648
Author(s):  
Ehsan M. Aghkonbad ◽  
Hassan Sedghi ◽  
Maryam M. Aghgonbad
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Spectroscopic Ellipsometry ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Zno Thin Films ◽  
Zno Films ◽  
Promising Alternative ◽  
Gap Energy ◽  
Doped Zno

Background: Al-doped ZnO thin films are considered as a promising alternative to ITO in optoelectronic applications. In this work, Al-doped ZnO thin films were prepared using sol-gel spin coating technique. Experimental: The optical properties of the films such as refractive index, extinction coefficient, dielectric function and the absorption coefficient were examined using spectroscopic ellipsometry method in the wavelength range of 300 to 900 nm. The effect of Al doping on ZnO thin films with different Al concentrations was significant. Tauc relation was used to estimate the optical band gap energy of the films. Results: The calculated values of band gap energy were obtained between 3.10 to 3.25 eV. Also the fraction of voids was calculated using Aspnes theory. Conclusion: The free carrier concentration value was obtained in the order of 1019 cm-3.

Effect of MCl (M = Na, K) addition on microstructure and electrical conductivity of forsterite

2020 ◽  
Vol 92 (1) ◽  
pp. 10901
Author(s):  
Saloua El Asri ◽  
Hamid Ahamdane ◽  
Lahoucine Hajji ◽  
Mohamed El Hadri ◽  
Moulay Ahmed El Idrissi Raghni ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Electrical Conductivity ◽  
Single Phase ◽  
Sol Gel ◽  
Complex Impedance ◽  
Transmission Spectra ◽  
Electrical Measurements ◽  
Cation Type ◽  
Edx Analyses ◽  
The Fourier Transform

Forsterite single phase powder Mg2SiO4 was synthesized by sol–gel method alongside with heat treatment, using two different cation alkaline salts MCl as mineralizers (M = Na, K) with various mass percentages (2.5, 5, 7.5, and 10 wt.%). In this work, we report on the effect of the cation type and the added amount of used mineralizer on microstructure and electrical conductivity of Mg2SiO4. The formation of forsterite started at 680–740  °C and at 630–700  °C with KCl and NaCl respectively, as shown by TG-DTA and confirmed by XRD. Furthermore, the Fourier transform infrared (FTIR) transmission spectra indicated bands corresponding to vibrations of forsterite structure. The morphology and elemental composition of sintered ceramics were examined by SEM-EDX analyses, while their densities, which were measured by Archimedes method, increased with addition of both alkaline salts. The electrical measurements were performed by Complex Impedance Spectroscopy. The results showed that electrical conductivity increased with the addition of both mineralizers, which was higher for samples prepared with NaCl than those prepared with KCl.

Sol-gel growth of Ni doped CdS on glass substrates: effect of spin coating speed and dopant concentration

2020 ◽  
Vol 10 ◽  
Author(s):  
Atefeh Nazari Setayesh ◽  
Hassan Sedghi
Keyword(s):  
Thin Films ◽  
Optical Properties ◽  
Spin Coating ◽  
Optical Band Gap ◽  
Dopant Concentration ◽  
Rotation Speed ◽  
Sol Gel ◽  
Band Gap Energy ◽  
Gap Energy ◽  
Glass Substrates

Background: In this work, CdS thin films were synthesized by sol-gel method (spin coating technique) on glass substrates to investigate the optical behavior of the film. Methods: Different substrate spin coating speeds of 2400, 3000, 3600 rpm and different Ni dopant concentrations of 0 wt.%, 2.5 wt.%, 5 wt.%) were investigated. The optical properties of thin films such as refraction index, extinction coefficient, dielectric constant and optical band gap energy of the layers were discussed using spectroscopic ellipsometry method in the wavelength range of 300 to 900 nm. Results: It can be deduced that substrate rotation speed and dopant concentration has influenced the optical properties of thin films. By decreasing rotation speed of the substrate which results in films with more thicknesses, more optical interferences were appeared in the results. Conclusion: The samples doped with Ni comparing to pure ones have had more optical band gap energy.

Structural and Magnetic Properties of Mn/Fe co-Doped ZnO Thin Films Prepared by Sol–Gel Technique

2014 ◽  
Vol 50 (8) ◽  
pp. 1-4 ◽  
Author(s):  
Robina Ashraf ◽  
Saira Riaz ◽  
Mahwish Bashir ◽  
Usman Khan ◽  
Shahzad Naseem
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Sol Gel ◽  
Zno Thin Films ◽  
Gel Technique ◽  
Structural And Magnetic Properties ◽  
Doped Zno ◽  
Co Doped

Multi-Phasic Ceramic Composites made by Sol-Gel Technique

1984 ◽  
Vol 32 ◽  
Author(s):  
Rustum Roy ◽  
S. Komarneni ◽  
D.M. Roy
Keyword(s):  
Single Phase ◽  
Crystal Size ◽  
Sol Gel ◽  
Ceramic Composites ◽  
Silver Halides ◽  
Metal Atoms ◽  
Metallic Salts ◽  
Second Phases ◽  
Gel Technique ◽  
Work Done

ABSTRACTInstead of aiming to prepare homogeneous gels and xerogels, this paper reports on work done to prepare deliberately diphasic materials. This has been achieved by three different paths: (1) mixing 2 sols; (2) mixing 1 sol with 1 solution; and (3) post formation diffusion of either one or two solutions.By the last named process we have made SiO2, mullite and alumina based composites, with silver halides, BaSO4, CdS, etc., as the dispersed phase. The crystal size can be confined to the initial pores by rapid diffusion giving rise to extremely fine second phases in the submicron range. Subsequent reduction of appropriate metallic salts can be used to give finely dispersed metals (e.g. Cu, Ni) in essentially any xerogel matrix. The open porosity makes these metal atoms very accessible.By the first two processes we have made both single phase and di-phasic gels of the same composition (prototype: mullite) and shown that though they cannot be distinguished by XRD, SEM, and TEM, by DTA and thermal processing, they are radically different. Such di-phasic gels store more metastable energy than any other solids.

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