Synthesis of Nano Iron Oxalate – Structures and Optical Transitions

2012 ◽  
Vol 1454 ◽  
pp. 273-277
Author(s):  
S. Lakshmi Reddy ◽  
Kenichi Uehara ◽  
Tamio Endo
Keyword(s):  
Near Infrared ◽  
Nano Particles ◽  
Spectral Studies ◽  
Optical Transitions ◽  
X Ray Diffraction ◽  
Microwave Reactor ◽  
Transmission Electron ◽  
Infrared Spectral ◽  
Particle Size And Shape ◽  
Double Decomposition

AbstractSynthesis of FeC2O42H2O nano particles was carried out by thermal double decomposition of solutions of oxalic acid dihydrate (C2H2O4 2H2O) and FeSO4 7H2O employing CATA -2R microwave reactor. Structural elucidation was carried out by employing X-ray diffraction, particle size and shape were studied by transmission electron microscopy and nature of bonding was investigated by Optical absorption and near-infrared spectral studies. The powder resulting from this method is possesses distorted rhombic octahedral structure. The particle grain size is about 50 nm. Details of optical transitions are mentioned in terms of energy states.

Characterization and Optical Studies of Short-Period SimGen Superlattices

1991 ◽  
Vol 220 ◽  
Author(s):  
H. Presting ◽  
H. Kibbel ◽  
E. Kasper ◽  
H. G. Grimmeiss ◽  
V. G. Nagesh
Keyword(s):  
Near Infrared ◽  
X Ray Diffraction ◽  
Optical Studies ◽  
Transmission Electron ◽  
Short Period ◽  
Region I ◽  
Infrared Spectral ◽  
Strained Layer Superlattices ◽  
Growth Quality ◽  
First Time

ABSTRACTShort-period SimGen (m monolayer (ML) Si, n ML Ge. n+m<∼40ML∼5.5nm) strained layer superlattices (SLS) are grown on <100> silicon by low temperature molecular beam epitaxy. Various characterization tools such as X-ray diffraction, transmission electron microscopy, Rutherford backscattering, Raman spectroscopy and photocapacitance measurements are used to analyze the growth quality, stram distribution, periodicity, interface sharpness and optical properties of the SLS. Recent photoluminescence experiments give hints of a direct bandgap transition from a 10 ML Si6Ge4 SLS in the near infrared spectral region. I-U and C-U measurements on mesa diodes (Am=2 10−4 cm2) are performed at various temperatures down to T=35K. Photocapacitance measurements show a Wannier-Stark localization of the superlattice states in a p+-n doped Si4Ge4 SLS diode, for the first time observed in type II superlattices. The observed transitions are believed to be defect or impurity related and are discussed in terms of a Wannier-Stark ladder behaviour.

Fabrication and Microstructure of Ge-Sb-S-CsCl Chalcogenide Glass Containing β-GeS2 Nanocrystals

2014 ◽  
Vol 665 ◽  
pp. 119-123
Author(s):  
Ji Yan Hao ◽  
Hai Tao Liu
Keyword(s):  
Chalcogenide Glass ◽  
Spherical Shape ◽  
Orthorhombic Phase ◽  
Far Infrared ◽  
X Ray Diffraction ◽  
Base Glass ◽  
X Ray ◽  
Transmission Electron ◽  
Infrared Spectral ◽  
Quenching Method

we report the fabrication and microstructure of Ge-Sb-S-CsCl chalcogenide glass containing β-GeS2 nanocrystals. A Ge-Sb-S-CsCl chalcogenide base glass with the better crystalline ability is first fabricated by melt-quenching method, and a further careful thermal process has led to the formation of β-GeS2 nanocrystals in the glass. Transmission electron microscopy showed that the size of β-GeS2 nanocrystals with nearly monodisperse spherical shape ranges from 30 to 45 nm in the glass. Powder X-ray diffraction results confirm that the β-GeS2 nanocrystals are of high crystallization with orthorhombic phase. Energy dispersive spectroscopy is employed for the information of nanocrystals glass composition. It is worthwhile to note that the obtained Ge-Sb-S-CsCl chalcogenide glass containing β-GeS2 nanocrystals still keeps higher transmittance in mid- and far- infrared spectral region.

Corrosion protection performance of titania nanoparticles filled poly(4-methyl-5-vinylthiazole) applied on mild steel in 3.5% sodium chloride solution

2020 ◽  
pp. 875608792093930 ◽  
Author(s):  
I Pugazhenthi ◽  
S Mohammed Ghouse
Keyword(s):  
Mild Steel ◽  
Electrochemical Impedance ◽  
Low Cost ◽  
Nano Particles ◽  
Titania Nanoparticles ◽  
X Ray Diffraction ◽  
Corrosive Media ◽  
X Ray ◽  
Polymer Hybrid ◽  
Transmission Electron

Mild steel materials have wide applications in marine construction, because they are low cost, available and easy to handle. However, they have to be protected from corrosive media by coating with polymer hybrid materials. This paper focuses on the anticorrosive properties of poly(4-methyl-5-vinylthiazole) PVTZ coatings on mild steel. Further the coating resistance is enhanced by incorporating Titania Nano particles (TiO2NPs). The nanoparticles were evaluated using X-ray diffraction studies (XRD) and transmission electron microscopy (TEM). PVTZ and its TiO2 nanocomposite were coated on mild steel. Their anticorrosive behavior was analyzed by potentiodynamic polarization and electrochemical impedance spectroscopy in 3.5% (w/v) NaCl.

X-ray diffraction and infrared spectral studies of unsaturated cellulose

1975 ◽  
Vol 13 (2) ◽  
pp. 65-70 ◽  
Author(s):  
H. C. Srivastava ◽  
A. K. Kulshreshtha ◽  
V. K. Srivastava
Keyword(s):  
Spectral Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Infrared Spectral

Growth and Magneto-Optical Properties of CaTbAlO4 Crystal

2011 ◽  
Vol 306-307 ◽  
pp. 1722-1727 ◽  
Author(s):  
Man Mei ◽  
Li Li Cao ◽  
Yan He ◽  
Ru Ru Zhang ◽  
Fei Yun Guo ◽  
...  
Keyword(s):  
Optical Properties ◽  
Single Crystal ◽  
Room Temperature ◽  
Near Infrared ◽  
Visible Region ◽  
Czochralski Method ◽  
Optical Devices ◽  
X Ray Diffraction ◽  
X Ray ◽  
Infrared Spectral

The calcium terbium aluminate (CaTbAlO4) single crystal was grown by Czochralski method successfully for the first time.The structure of the crystal was determined by X-ray diffraction analysis.The transmission spectrum of the crystal was measured at room temperature at the wavelength of 400-1500nm.The specific Faraday rotation of the single crystal was surveyed at room temperature at the wavelength 532nm, 633nm, and 1064nm respectively.The Verdet constants of the CaTbAlO4 crystal are calculated and the results show that the Verdet constants of CaTbAlO4 are around 110% higher than that of TGG in the visible and near-infrared spectral region.Therefore,crystal CaTbAlO4 can be promising material for the fabrication of magneto-optical devices in the visible region.

Magnetoelectric and magnetic studies of the Bi1–xCaxFeO3 multiferrioc system

2014 ◽  
Vol 92 (5) ◽  
pp. 389-394 ◽  
Author(s):  
S.F. Mansour ◽  
N.I. Abu-Elsaad ◽  
T.A. Elmosalami
Keyword(s):  
Room Temperature ◽  
Energy Levels ◽  
Resonance Field ◽  
X Ray Diffraction ◽  
Magnetic Studies ◽  
X Ray ◽  
Transmission Electron ◽  
Spin Resonance ◽  
Particle Size And Shape ◽  
Combustion Technique

Bi1–xCaxFeO3 was prepared by the flash autocombustion combustion technique. X-ray diffraction analysis showed a Rhombohedrally distorted hexagonal perovskite structure with space group R3c. The particle size and shape were studied by transmission electron microscope. Magnetization studies at room temperature showed superparamagnetic behavior for the prepared nanoparticles. Magnetoelectric coefficient characterized as magnetic field – induced polarization was investigated. The Lande factor (g), resonance field (Br), relaxation time (τ), and the energy between two adjacent degenerate spin energy levels (ΔE) were estimated from the electron spin resonance spectra.

scholarly journals Single Er3+, Yb3+: KGd3F10 Nanoparticles for Nanothermometry

2021 ◽  
Vol 9 ◽  
Author(s):  
Karmel de Oliveira Lima ◽  
Luiz Fernando dos Santos ◽  
Rodrigo Galvão ◽  
Antonio Claudio Tedesco ◽  
Leonardo de Souza Menezes ◽  
...  
Keyword(s):  
Intensity Ratio ◽  
Near Infrared ◽  
Continuous Wave ◽  
Thermal Sensitivity ◽  
Spectroscopic Studies ◽  
X Ray Diffraction ◽  
Thermal Range ◽  
Transmission Electron ◽  
Biological Interest ◽  
Nir Emission

Among several optical non-contact thermometry methods, luminescence thermometry is the most versatile approach. Lanthanide-based luminescence nanothermometers may exploit not only downshifting, but also upconversion (UC) mechanisms. UC-based nanothermometers are interesting for biological applications: they efficiently convert near-infrared radiation to visible light, allowing local temperatures to be determined through spectroscopic investigation. Here, we have synthesized highly crystalline Er3+, Yb3+ co-doped upconverting KGd3F10 nanoparticles (NPs) by the EDTA-assisted hydrothermal method. We characterized the structure and morphology of the obtained NPs by transmission electron microscopy, X-ray diffraction, Raman spectroscopy, and dynamic light scattering. Nonlinear spectroscopic studies with the Er3+, Yb3+: KGd3F10 powder showed intense green and red emissions under excitation at 980 and 1,550 nm. Two- and three-photon processes were attributed to the UC mechanisms under excitation at 980 and 1,550 nm. Strong NIR emission centered at 1,530 nm occurred under low 980-nm power densities. Single NPs presented strong green and red emissions under continuous wave excitation at 975.5 nm, so we evaluated their use as primary nanothermometers by employing the Luminescence Intensity Ratio technique. We determined the temperature felt by the dried NPs by integrating the intensity ratio between the thermally coupled 2H11/2→4I15/2 and 4S3/2→4I15/2 levels of Er3+ ions in the colloidal phase and at the single NP level. The best thermal sensitivity of a single Er3+, Yb3+: KGd3F10 NP was 1.17% at the single NP level for the dry state at 300 K, indicating potential application of this material as accurate nanothermometer in the thermal range of biological interest. To the best of our knowledge, this is the first promising thermometry based on single KGd3F10 particles, with potential use as biomarkers in the NIR-II region.

Synthesis of Colloidal Gold Nanorods with Plasmon Absorbance Wavelength in the Near Infrared Region

MRS Advances ◽  
2016 ◽  
Vol 1 (30) ◽  
pp. 2181-2186 ◽  
Author(s):  
Luis M. Angelats-Silva ◽  
David Asmat-Campos ◽  
Henry León-León ◽  
Kevin A. Wilkinson ◽  
Daniel A. Sánchez-Vaca ◽  
...  
Keyword(s):  
Silver Nitrate ◽  
Gold Nanorods ◽  
Colloidal Gold ◽  
Near Infrared ◽  
Infrared Region ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Absorbance Peak ◽  
Silver Nitrate Concentration

ABSTRACTWe report preparation and characterization of colloidal gold nanorods (AuNR) with plasmon absorbance over 950 nm and an aspect ratio of 7.2 by tuning silver nitrate concentration and the CTAB/BDAC ratio during growth. Samples were analyzed by scanning transmission electron microscopy, X-ray diffraction, UV-vis absorption spectroscopy and measurement of zeta potential. Addition of 170 μM silver nitrate to the CTAB-containing reaction mixture allowed preparation of AuNRs with a maximum absorbance peak at 941.8 nm and a yield around 96%. Optimization of the BDAC/CTAB ratio allowed for a further redshift of the absorbance maximum to 954.0 nm, but with poorer yields.

Formation and characterization of silica-coated HAP particles

2012 ◽  
Vol 19 (2) ◽  
pp. 107-112
Author(s):  
Hongxin Wang ◽  
Xiaoming Chen ◽  
Dongji Cheng
Keyword(s):  
Colloidal Stability ◽  
Particle Surface ◽  
Silica Coating ◽  
Esterification Reaction ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Transmission Electron ◽  
Infrared Spectral ◽  
Hydrolysis Of

AbstractNanophase hydroxyapatite (HAP) particles were coated with silica via the hydrolysis of tetraethyl orthosilicate after a dodecyl alcohol based esterification reaction. The nanocomposite particles were characterized by transmission electron spectroscopy, scanning electron microscopy, X-ray diffraction, Fourier transform infrared (FTIR) spectroscopy, thermogravimetry and differential scanning calorimetry, sedimentation time and zeta potential (ζ) studies. A sequential change in infrared spectral features characteristic of HAP was accompanied by an increase in features characteristic of silica as revealed by FTIR. The silica coating enhanced the colloidal stability of HAP in aqueous suspensions. This behavior can be explained based on a heterocoagulation coating mechanism in which silica clusters adsorb onto the HAP particle surface.

Photoinduced formation of colloidal Au by a near-infrared femtosecond laser

2003 ◽  
Vol 18 (7) ◽  
pp. 1710-1714 ◽  
Author(s):  
Chongjun Zhao ◽  
Shiliang Qu ◽  
Jianrong Qiu ◽  
Congshan Zhu
Keyword(s):  
Femtosecond Laser ◽  
Absorption Spectra ◽  
Near Infrared ◽  
Au Nanoparticles ◽  
X Ray Diffraction ◽  
Local Formation ◽  
X Ray ◽  
Transmission Electron ◽  
Red Color ◽  
Yellow Orange

A Au colloid was prepared in a 5 mM HAuCl4 solution through irradiation with a focused infrared femtosecond laser at 800 nm. The Au colloid was characterized by absorption spectra, transmission electron microscopy, and x-ray diffraction analysis. The appearance of absorption peak around 526 nm in the absorption spectra and the wine-red color of sample solution HAuCl4 under focused laser irradiation verified the formation of Au colloid. The solution color changed in the order of yellow → orange → wine-red due to the local formation of Au nanoparticles near the focus. The pulse energy, focus position of laser beam, and solvent composite play important roles in formation, grain size, and stability of the Au colloid. A mechanism for the precipitate of Au nanoparticles was proposed, and a multiphoton process of femtosecond laser was involved.

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