scholarly journals PREPARATION AND CHARACTERIZATION OF ZnO NANOPARTICLES BY SOLVENT FREE METHOD

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Savka Janković ◽  
Dragana Milisavić ◽  
Tanja Okolić ◽  
Dijana Jelić
Keyword(s):  
Band Gap ◽  
Zno Nanoparticles ◽  
Band Gap Energy ◽  
Zinc Nitrate ◽  
Solvent Free ◽  
Band Model ◽  
Nitrate Hexahydrate ◽  
Gap Energy ◽  
Tauc Plot

ZnO nanoparticles have numerous applications as photo catalysts, gas sensors, UV lasers, as optoelectronic and microelectronic devices or in cosmetic field. ZnO nanoparticles were synthesized by solvent free method using zinc nitrate hexahydrate as precursor and glycerol as dispersant, without solvent present. This method proved to be very simple, economic and ecofriendly. Zinc nitrate and glycerol were mixed in different ratio in order to avoid and overcome a possibility of agglomeration. Characterization of samples was performed by UV/VIS and FTIR spectrophotometry. The strongest absorption appeared at wavelength 206 nm. Using combination of UV/VIS spectrophotometry and hyperbolic band model (HBM) particles size of ZnO particles were evaluated to 2.06 nm. Additionally, using Tauc plot, a band gap energy was determined. Band gap energy of ZnO nanoparticles amounted to 5.00 eV. IR spectrum showed existence of ZnO in interval 600- 400 cm-1.

Synthesis and characterization of a mixture of CoFe2O4 and MgFe2O4 from layered double hydroxides: Band gap energy and magnetic responses

2014 ◽  
Vol 369 ◽  
pp. 249-259 ◽  
Author(s):  
Ulises A. Agú ◽  
Marcos I. Oliva ◽  
Sergio G. Marchetti ◽  
Angélica C. Heredia ◽  
Sandra G. Casuscelli ◽  
...  
Keyword(s):  
Band Gap ◽  
Layered Double Hydroxides ◽  
Band Gap Energy ◽  
Synthesis And Characterization ◽  
Gap Energy ◽  
Double Hydroxides

Spectroscopic Ellipsometry Analysis of InGaN/GaN and AlGaN/GaN Heterostructures Using a Parametric Dielectric Function Model

1999 ◽  
Vol 595 ◽  
Author(s):  
J. Wagner ◽  
A. Ramakrishnan ◽  
H. Obloh ◽  
M. Kunzer ◽  
K. Köhler ◽  
...  
Keyword(s):  
Band Gap ◽  
Dielectric Function ◽  
Spectroscopic Ellipsometry ◽  
Composition Dependence ◽  
Band Gap Energy ◽  
Function Model ◽  
Gap Energy ◽  
The Individual ◽  
Gap Data

AbstractSpectroscopic ellipsometry (SE) has been used for the characterization of AlGaN/GaN and InGaN/GaN heterostructures. The resulting pseudodielectric function spectra were analyzed using a multilayer approach, describing the dielectric functions of the individual layers by a parametric oscillator model. From this analysis, the dielectric function spectra of GaN, AlxGa1−xN (x≤0.16), and In0.13Ga0.87N were deduced. Further, the dependence of the AlxGa1−xN band gap energy on the Al mole fraction was derived and compared with photoluminescence data recorded on the same material. The SE band gap data are compatible with a bowing parameter close to 1 eV for the composition dependence of the AlxGa1−xN gap energy. Finally, the parametric dielectric functions have been used to model the pseudodielectric function spectrum of a complete GaN/AlGaN/InGaN LED structure.

scholarly journals Band-Gap Energies of Choline Chloride and Triphenylmethylphosphoniumbromide-Based Systems

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1495 ◽  
Author(s):  
Alberto Mannu ◽  
Maria Enrica Di Pietro ◽  
Andrea Mele
Keyword(s):  
Hydrogen Bond ◽  
Ethylene Glycol ◽  
Band Gap ◽  
Lewis Acids ◽  
Choline Chloride ◽  
Band Gap Energy ◽  
Hydrogen Bond Acceptor ◽  
Gap Energy ◽  
Tauc Plot ◽  
Vis Spectroscopy

UV–VIS spectroscopy analysis of six mixtures containing choline chloride or triphenylmethylphosphonium bromide as the hydrogen bond acceptor (HBA) and different hydrogen bond donors (HBDs, nickel sulphate, imidazole, d-glucose, ethylene glycol, and glycerol) allowed to determine the indirect and direct band-gap energies through the Tauc plot method. Band-gap energies were compared to those relative to known choline chloride-containing deep band-gap systems. The measurements reported here confirmed the tendency of alcohols or Lewis acids to increment band-gap energy when employed as HBDs. Indirect band-gap energy of 3.74 eV was obtained in the case of the triphenylmethylphosphonium bromide/ethylene glycol system, which represents the smallest transition energy ever reported to date for such kind of systems.

scholarly journals Aluminum doping tunes band gap energy level as well as oxidative stress-mediated cytotoxicity of ZnO nanoparticles in MCF-7 cells

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohd Javed Akhtar ◽  
Hisham A. Alhadlaq ◽  
Aws Alshamsan ◽  
M.A. Majeed Khan ◽  
Maqusood Ahamed
Keyword(s):  
Oxidative Stress ◽  
Energy Level ◽  
Band Gap ◽  
Zno Nanoparticles ◽  
Band Gap Energy ◽  
Aluminum Doping ◽  
Gap Energy ◽  
Mcf 7

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 UJI UV-VIS LAPISAN TiO2/N2 UNTUK MENENTUKAN BAND GAP ENERGY

2018 ◽  
Vol 3 (2) ◽  
pp. 6-10
Author(s):  
Devi Indriani ◽  
Helga Dwi Fahyuan ◽  
Ngatijo Ngatijo
Keyword(s):  
Band Gap ◽  
Wavelength Range ◽  
Energy Band ◽  
Nitrogen Doping ◽  
Band Gap Energy ◽  
Tio2 Layer ◽  
Energy Band Gap ◽  
Gap Energy ◽  
Transmittance Band

[Title: TEST UV-VIS LAYER TiO2/N2 FOR DETERMINING BAND GAP ENERGY] The effect of nitrogen doping variation on energy band gap in TiO2 layer grown by doctor blade technique. The TiO2/N2 layer was prepared with concentrations of 0%, 15%, 25% and 25% calcined at 500°C for 3 hours. Characterization of band gap energy by using the UV-Vis spectrometer at a wavelength range of 200 nm-700 nm. The band gap energy is obtained by using the Swanepoel equation and Touch Plot method. The results showed that doping of nitrogen can decrease the band gap energy of 3.9250 eV, 3.8750 eV, 3.8375 eV and 3.9125 eV, respectively. The smallest energy band gap is obtained at 25% concentration that is 3.8375eV. Keywords: Coating TiO2/N2, transmittance, Band gap energy

scholarly journals Structural, Optical, and Magnetic Characterization of Spinel Zinc Chromite Nanocrystallines Synthesised by Thermal Treatment Method

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Salahudeen A. Gene ◽  
Elias Saion ◽  
Abdul H. Shaari ◽  
Mazliana A. Kamarudin ◽  
Naif M. Al-Hada ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Band Gap ◽  
Treatment Method ◽  
Band Gap Energy ◽  
Resonance Spectroscopy ◽  
Magnetic Characterization ◽  
X Ray ◽  
Gap Energy ◽  
Zinc Chromite

The present study reports the structural and magnetic characterization of spinel zinc chromite (ZnCr2O4) nanocrystallines synthesized by thermal treatment method. The samples were calcined at different temperatures in the range of 773 to 973 K. Polyvinylpyrrolidone was used to control the agglomeration of the nanoparticles. The average particle size of the synthesized nanocrystals was determined by powder X-ray diffraction which shows that the crystallite size increases from 19 nm at 773 K to 24 nm at 973 K and the result was in good agreement with the transmission electron microscopy images. The elemental composition of the samples was determined by energy dispersed X-ray spectroscopy which confirmed the presence of Zn, Cr, and O in the final products. Fourier transform infrared spectroscopy also confirmed the presence of metal oxide bands for all the samples calcined at different temperature. The band gap energy was calculated from UV-vis reflectance spectra using the Kubelka-Munk function and the band gap energy of the samples was found to decrease from 4.03 eV at 773 K to 3.89 eV at 973 K. The magnetic properties were also demonstrated by electron spin resonance spectroscopy, the presence of unpaired electrons was confirmed, and the resonant magnetic field and theg-factorof the calcined samples were also studied.

scholarly journals Behavior of Ternary Mixtures of Hydrogen Bond Acceptors and Donors in Terms of Band Gap Energies

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3418
Author(s):  
Alberto Mannu ◽  
Francesca Cardano ◽  
Salvatore Baldino ◽  
Andrea Fin
Keyword(s):  
Hydrogen Bond ◽  
Band Gap ◽  
Choline Chloride ◽  
Band Gap Energy ◽  
Ternary Mixtures ◽  
Hydrogen Bond Donor ◽  
Multivariate Statistical ◽  
Gap Energy ◽  
Tauc Plot ◽  
Simple Lattice

Three ternary mixtures composed by choline chloride (ChCl), ethylene glycol (EG), and a second hydrogen bond donor (HBD) as ethanol (A), 2-propanol (B), and glycerol (C) were studied in terms of composition related to the band gap energy (BGE). A Design of Experiments (DoE) approach, and in particular a Simple Lattice three-components design, was employed for determining the variation of the BGE upon the composition of each system. UV-VIS analysis and subsequent Tauc plot methodology provided the data requested from the DoE, and multivariate statistical analysis revealed a drop of the BGE in correspondence to specific binary compositions for systems A and B. In particular, a BGE of 3.85 eV was registered for the mixtures ChCl/EtOH (1:1) and ChCl/2-propanol (1:1), which represents one of the lowest values ever observed for these systems.

scholarly journals Spectroscopic Ellipsometry Analysis of InGaN/GaN and AlGaN/GaN Heterostructures Using a Parametric Dielectric Function Model

2000 ◽  
Vol 5 (S1) ◽  
pp. 775-781
Author(s):  
J. Wagner ◽  
A. Ramakrishnan ◽  
H. Obloh ◽  
M. Kunzer ◽  
K. Köhler ◽  
...  
Keyword(s):  
Band Gap ◽  
Dielectric Function ◽  
Spectroscopic Ellipsometry ◽  
Composition Dependence ◽  
Band Gap Energy ◽  
Function Model ◽  
Gap Energy ◽  
The Individual ◽  
Gap Data

Spectroscopic ellipsometry (SE) has been used for the characterization of AlGaN/GaN and InGaN/GaN heterostructures. The resulting pseudodielectric function spectra were analyzed using a multilayer approach, describing the dielectric functions of the individual layers by a parametric oscillator model. From this analysis, the dielectric function spectra of GaN, AlxGa1−xN (x≤0.16), and In0.13Ga0.87N were deduced. Further, the dependence of the AlxGa1−xN band gap energy on the Al mole fraction was derived and compared with photoluminescence data recorded on the same material. The SE band gap data are compatible with a bowing parameter close to 1 eV for the composition dependence of the AlxGa1−xN gap energy. Finally, the parametric dielectric functions have been used to model the pseudodielectric function spectrum of a complete GaN/AlGaN/InGaN LED structure.

scholarly journals Synthesis and Characterization of MgO Doped ZnO Nanorods Prepared by Solution Immersion Method and their Effect on Energy Band Gap

2019 ◽  
Vol 7 (4.14) ◽  
pp. 186
Author(s):  
Z Khusaimi ◽  
N A.M. Asib ◽  
S Z. Umbaidilah ◽  
A N. Afaah ◽  
C N.E. Syafika ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
Band Gap ◽  
Zno Nanorods ◽  
Annealing Treatment ◽  
Band Gap Energy ◽  
Powder Form ◽  
Immersion Method ◽  
Gap Energy ◽  
Tauc Plot ◽  
Doped Zno

In this research, solid powder form ZnO and MgO-doped ZnO were prepared by using solution immersion method. Mg divalent cation with different atomic percentage of 0.5%, 1.0% and 1.5% were added in 0.04 M of Zn2+ solution containing zinc nitrate hexahydrates as precursor and hexamethylene tetraamine as stabilizer. Annealing treatment was consequently carried out to transform the precursors into oxide forms. ZnO and MgO-doped ZnO were successfully obtained and the surface morphology, crystallite size and elemental composition were studied using Field Emission Scanning Electron Microscope (FESEM) and Energy dispersive X-Ray (EDX) respectively. The band gap energy was determined using Ultraviolet-Visible spectrophotometer (UV-Vis). FESEM images showed that the powder form of ZnO and MgO-doped ZnO consist of rod-like shape. A 0.5% of MgO-doped ZnO sample has smallest size of rods with higher aspect ratio compared to others. The EDX result revealed that the sample composed of Zn, O and Mg in the sample. The band gap energy for all samples was determined using Tauc plot and it was found that the band gap energy is reduced with 1.0 and 1.5 % doping while increased at 0.5% doping. The band gap energy was found to range between 3.23 eV to 3.26 eV. The 0.5% of Mg-doped ZnO with higher aspect ratio shows the highest band gap energy value.  

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