Synthesis, characterization and optical band gap of NiO nanoparticles derived from anthranilic acid precursors via a thermal decomposition route

Polyhedron ◽  
2011 ◽  
Vol 30 (3) ◽  
pp. 470-476 ◽  
Author(s):  
Nasser Mohammed Hosny
Keyword(s):  
Thermal Decomposition ◽  
Band Gap ◽  
Anthranilic Acid ◽  
Optical Band Gap ◽  
Nio Nanoparticles

Raman shift, Néel temperature, and optical band gap of NiO nanoparticles

2020 ◽  
Vol 22 (10) ◽  
pp. 5735-5739 ◽  
Author(s):  
Bai Pan ◽  
Xianshang Meng ◽  
Yidong Xia ◽  
Haiming Lu ◽  
Hui Li
Keyword(s):  
Band Gap ◽  
Optical Band Gap ◽  
Raman Shift ◽  
Neel Temperature ◽  
Nio Nanoparticles ◽  
Néel Temperature

Unified models were developed to describe size dependences of Raman shift, Néel temperature and optical band gap for NiO nanoparticles.

scholarly journals Structural, Magnetic and Photocatalytic Properties of BiFeO3 Nanoparticles

2017 ◽  
Vol 7 (3) ◽  
Author(s):  
Seyyed Morteza Masoudpanah
Keyword(s):  
Thermal Decomposition ◽  
Band Gap ◽  
Optical Band Gap ◽  
Visible Region ◽  
Spherical Shape ◽  
Phase Evolution ◽  
Weak Ferromagnetism ◽  
Visible Light Photocatalyst ◽  
Bifeo3 Nanoparticles ◽  
Vis Spectroscopy

Single phase BiFeO3 nanoparticles as a visible light photocatalyst were successfully synthesized by thermal decomposition of the glyoxylate precursor. The glyoxylate precursors were formed by the redox reaction between ethylene glycol and nitrate ions. The phase evolution, structure and optical properties of BiFeO3 nanoparticles were characterized by X-ray diffraction, electron microscopy and UV–Vis spectroscopy methods. The BiFeO3 nanoparticles showed the quasi spherical shape. The BiFeO3 nanoparticles synthesized at 500 °C showed the weak ferromagnetism behavior, due to the size confinement effect, in spite of the antiferromagnetic behavior of the BiFeO3 nanoparticles synthesized at 600 °C. The BiFeO3 nanoparticles exhibited strong absorption in the visible region with the optical band gap calculated from Tauc’s plot. The optical band gap decreased from 2.10 to 2.08 eV by the increasing of thermal decomposition temperature. Moreover, the BiFeO3 nanoparticles were used for the degradation of methylene blue as a typical dye pollutant under direct sunlight irradiation.

Stability Investigation in the Optical Properties of Thermally Evaporated Ge5Se95-x Znx Thin Films

2015 ◽  
Vol 7 (3) ◽  
pp. 1923-1930
Author(s):  
Austine Amukayia Mulama ◽  
Julius Mwakondo Mwabora ◽  
Andrew Odhiambo Oduor ◽  
Cosmas Mulwa Muiva ◽  
Boniface Muthoka ◽  
...  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Optical Band Gap ◽  
Thermal Evaporation ◽  
Optical Transition ◽  
Bulk Material ◽  
Band Gap Energy ◽  
Optical Absorbance ◽  
Gap Energy ◽  
Constituent Elements

 Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 ≤ x ≤ 4 at.%) has been prepared from high purity constituent elements. Thin films from the bulk material were deposited by vacuum thermal evaporation. Optical absorbance measurements have been performed on the as-deposited thin films using transmission spectra. The allowed optical transition was found to be indirect and the corresponding band gap energy determined. The variation of optical band gap energy with the average coordination number has also been investigated based on the chemical bonding between the constituents and the rigidity behaviour of the system’s network.

scholarly journals Polymer Thermal Treatment Production of Cerium Doped Willemite Nanoparticles: An Analysis of Structure, Energy Band Gap and Luminescence Properties

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1118
Author(s):  
Ibrahim Mustapha Alibe ◽  
Khamirul Amin Matori ◽  
Mohd Hafiz Mohd Zaid ◽  
Salisu Nasir ◽  
Ali Mustapha Alibe ◽  
...  
Keyword(s):  
Solid State ◽  
Thermal Treatment ◽  
Band Gap ◽  
Optical Band Gap ◽  
Dopant Concentration ◽  
Blue Emission ◽  
Green Emission ◽  
Band Gap Energy ◽  
Solid State Lighting ◽  
Gap Energy

The contemporary market needs for enhanced solid–state lighting devices has led to an increased demand for the production of willemite based phosphors using low-cost techniques. In this study, Ce3+ doped willemite nanoparticles were fabricated using polymer thermal treatment method. The special effects of the calcination temperatures and the dopant concentration on the structural and optical properties of the material were thoroughly studied. The XRD analysis of the samples treated at 900 °C revealed the development and or materialization of the willemite phase. The increase in the dopant concentration causes an expansion of the lattice owing to the replacement of larger Ce3+ ions for smaller Zn2+ ions. Based on the FESEM and TEM micrographs, the nanoparticles size increases with the increase in the cerium ions. The mean particles sizes were estimated to be 23.61 nm at 1 mol% to 34.02 nm at 5 mol% of the cerium dopant. The optical band gap energy of the doped samples formed at 900 °C decreased precisely by 0.21 eV (i.e., 5.21 to 5.00 eV). The PL analysis of the doped samples exhibits a strong emission at 400 nm which is ascribed to the transition of an electron from localized Ce2f state to the valence band of O2p. The energy level of the Ce3+ ions affects the willemite crystal lattice, thus causing a decrease in the intensity of the green emission at 530 nm and the blue emission at 485 nm. The wide optical band gap energy of the willemite produced is expected to pave the way for exciting innovations in solid–state lighting applications.

scholarly journals Resonance and antiresonance in Raman scattering in GaSe and InSe crystals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
M. Osiekowicz ◽  
D. Staszczuk ◽  
K. Olkowska-Pucko ◽  
Ł. Kipczak ◽  
M. Grzeszczyk ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Temperature Effect ◽  
Band Gap ◽  
Raman Spectra ◽  
Quantum Interference ◽  
Optical Band Gap ◽  
Phonon Coupling ◽  
Phonon Modes ◽  
Electron Phonon Coupling ◽  
Resonant Raman

AbstractThe temperature effect on the Raman scattering efficiency is investigated in $$\varepsilon$$ ε -GaSe and $$\gamma$$ γ -InSe crystals. We found that varying the temperature over a broad range from 5 to 350 K permits to achieve both the resonant conditions and the antiresonance behaviour in Raman scattering of the studied materials. The resonant conditions of Raman scattering are observed at about 270 K under the 1.96 eV excitation for GaSe due to the energy proximity of the optical band gap. In the case of InSe, the resonant Raman spectra are apparent at about 50 and 270 K under correspondingly the 2.41 eV and 2.54 eV excitations as a result of the energy proximity of the so-called B transition. Interestingly, the observed resonances for both materials are followed by an antiresonance behaviour noticeable at higher temperatures than the detected resonances. The significant variations of phonon-modes intensities can be explained in terms of electron-phonon coupling and quantum interference of contributions from different points of the Brillouin zone.

scholarly journals ZnSnN 2 in Real Space and k‐Space: Lattice Constants, Dislocation Density, and Optical Band Gap

2021 ◽  
pp. 2100015
Author(s):  
Vegard Skiftestad Olsen ◽  
Vetle Øversjøen ◽  
Daniela Gogova ◽  
Béla Pécz ◽  
Augustinas Galeckas ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Band Gap ◽  
Optical Band Gap ◽  
Real Space ◽  
Lattice Constants ◽  
Space Lattice
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