Photoelectric and magnetic properties of chemically synthesized Cd-Ni Ferrite nanomagnetic particles

2022 ◽  
Author(s):  
Abideen Adejuwon Ibiyemi ◽  
Yusuf taofeek Gbadebo ◽  
Olusayo Olubosede ◽  
Akinrinola Olusola ◽  
Hamzat Adebayo Akande
Keyword(s):  
Light Emission ◽  
Stoichiometric Composition ◽  
Photoelectric Effect ◽  
Excitation Wavelength ◽  
Optical Losses ◽  
Ir Detector ◽  
Average Grain Size ◽  
Carboxylic Groups ◽  
Yellow Orange ◽  
Co Precipitation

Abstract Cadmium nickel (Cd-Ni) ferrite samples have been successfully synthesized via chemical co-precipitation technique. The structural analysis revealed the formation of FCC framework and Fe-phase in a trivalent state. The crystallite size is decreased with increasing Cd2+ ion composition whereas the lattice constant is increased. SEM was used to obtain the surface morphology and average grain size of the microstructure. The FTIR shows the formation of metal oxide, hydroxyl and carboxylic groups. EDX revealed the formation of Ni2+, Cd2+, Fe3+, and O2- ions in proper stoichiometric composition. Large optical losses were revealed by Cd2+ poor-NiFe2O4 samples whereas Cd2+ rich-CdxNi1-xFe2O4 samples revealed low optical losses and showed enhanced photoconductivity and photoelectric effect. Result from optical analysis showed that Cd2+ rich-CdxNi1-xFe2O4 nanoparticles can be used as infrared (IR) detector, ultraviolet (UV) filter and in optoelectronics device applications. VSM measurement showed an increase in saturation magnetization and decrease in coercivity as Cd2+ ion content is increased. The remanance magnetization and magnetic anisotropy were also examined. Photoluminescence (PL) spectroscopy examined the nature of the light emission of the samples at the excitation wavelength 380 nm and emission of series of colours such as red, green, yellow, orange and violet light at different wavelengths were found.

Structural and Optical Characterization of Pure and Mn2+ -Doped ZnS Nanoparticles Prepared by Solvothermal Method

2013 ◽  
Vol 678 ◽  
pp. 61-66
Author(s):  
T.E. Manjulavalli ◽  
A.G. Kannan
Keyword(s):  
Solvothermal Method ◽  
Blue Emission ◽  
Spherical Shape ◽  
Blue Shift ◽  
Excitation Wavelength ◽  
Zns Nanoparticles ◽  
X Ray ◽  
Sem Image ◽  
Average Grain Size ◽  
Yellow Orange

ZnS and Mn2+doped ZnS nanoparticles are synthesized through a simple solvothermal method. The structural and optical properties of pure and doped ZnS nanoparticles were studied using X-ray powder diffraction (XRD), scanning electron microscopy (SEM), UV-vis absorption and photoluminescence spectroscopy (PL). X-ray diffraction analysis reveals that undoped and Mn2+doped ZnS crystallizes in cubic structures. The average grain size of the nanoparticles lies in the range of 2.2 to 4.8 nm. The SEM image shows that pure and doped nanoparticles are in spherical shape. The optical absorption spectrum exhibits a clear blue shift for ZnS and Mn2+doped ZnS nanoparticles when compared with bulk ZnS. Photoluminescence spectra recorded for ZnS nanoparticles exhibits an emission peak centered around 428 nm for an excitation wavelength of 330 nm. However, for Mn2+doped samples, an yellow–orange emission is observed along with the blue emission.

Orange light emission from co-precipitation derived CaZr4(PO4)6 doped with Sm3+ phosphor

Optik ◽  
2021 ◽  
pp. 167229
Author(s):  
Vijay Singh ◽  
Yatish R. Parauha ◽  
S.J. Dhoble ◽  
Venkata Krishnaiah Kummara ◽  
N. Ravi
Keyword(s):  
Light Emission ◽  
Co Precipitation

Tunable luminescence and white light emission of porphyrin-zinc coordination assemblies

2018 ◽  
Vol 22 (09n10) ◽  
pp. 821-830 ◽  
Author(s):  
Zheng Wang ◽  
Jian-Hua Zhang ◽  
Cheng-Yi Zhu ◽  
Shao-Yun Yin ◽  
Mei Pan
Keyword(s):  
White Light ◽  
Light Emission ◽  
Three Dimensional ◽  
White Light Emission ◽  
Molar Ratio ◽  
Excitation Wavelength ◽  
Temperature Dependent ◽  
Long Wavelength ◽  
Linear Formula ◽  
Zinc Coordination

Bipodal ligand 5,15-bis(4-carboxyphenyl) porphyrin (H[Formula: see text]DCPP) was designed and synthesized. By adjusting the molar ratio of H[Formula: see text]DCPP, ancillary ligand 4,4-bipyridine (bpy) and zinc acetate salts, three novel coordination assemblies, namely, zero-dimensional dimeric [Zn[Formula: see text](H[Formula: see text]DCPP)[Formula: see text] ·bpy] ·4H[Formula: see text]O ·4DMF (Zn-D), two-dimensional polymeric {[Zn[Formula: see text](DCPP) ·bpy[Formula: see text] ·H[Formula: see text]O ·DMF[Formula: see text]] ·solvent}[Formula: see text] (Zn-2D), and three-dimensional polymeric [Zn[Formula: see text](DCPP) ·bpy[Formula: see text]][Formula: see text] (Zn-3D) were assembled. Due to the delicate integration of multiple chromophores in the coordination space combining bpy, DCPP and MLCT emissions together, photoluminescence (PL) of the three porphyrin-zinc coordination assemblies differ from each other and color tone is tunable from blue to orange with changes of the excitation wavelength. In particular, white light emission (WLE) can be observed by the excitation of 270 to 290 nm, representing the first examples of single component WLE compounds based on porphyrin ligands. Furthermore, temperature-dependent luminescence results in a linear [Formula: see text]–[Formula: see text] relationship in Zn-2D and Zn-3D assemblies, applicable for long wavelength red-emitting thermometers.

Structural and Optical Properties of Pure NiO Nanoparticles and NiO-Mn2O3, NiO-CdO, NiO-Pb2O3, NiO-ZnO Nanocomposites

2021 ◽  
Vol 14 (5) ◽  
pp. 409-417
Keyword(s):  
Nickel Oxide ◽  
Green Emission ◽  
Hexagonal Structure ◽  
Precipitation Method ◽  
Nio Nanoparticles ◽  
Structural And Optical Properties ◽  
Suitable Material ◽  
Structure Morphology ◽  
Average Grain Size ◽  
Co Precipitation

Abstract: Pure nickel oxide (NiO) nanoparticles and NiO-Mn2O3, NiO-CdO, NiO-Pb2O3, NiO –ZnO nanocomposites were synthesized by co-precipitation method. The PXRD studies revealed that NiO, Mn2O3 and CdO possessed cubic structure, Pb2O3 possessed monoclinic structure, ZnO possessed hexagonal structure and confirmed the presence of polycrystallinity nature of NiO and Mn2O3, CdO, Pb2O3, ZnO in the nanocomposites. The average grain size of NiO nanoparticles was found to be 30.10 nm using Debye Scherer’s formula. The FESEM images of NiO nanoparticles and their nanocomposites revealed spherical shaped structure and NiO-Pb2O3 revealed needle shaped rod-like structure. EDAX analysis confirmed the composition of NiO nanoparticles and their nanocomposites. Raman spectra exhibited characteristic peaks of pure NiO and that of NiO- Mn2O3, NiO-CdO, NiO- Pb2O3, NiO-ZnO in the synthesized nanocomposites. In the PL spectra, blue and green emission was observed in the samples. UV-vis spectra revealed the absorption peaks of NiO nanoparticles and their nanocomposites. Thus, the synthesized NiO- Mn2O3, NiO-CdO, NiO - Pb2O3 and NiO-ZnO nanocomposites can be a suitable material for electrocatalysis applications. Keywords: Nickel oxide nanocomposites, Structure, Morphology, Absorption, Luminescence.

Optical and microstructural properties of self-assembled InAs quantum structures in silicon

Open Physics ◽  
2011 ◽  
Vol 9 (2) ◽  
Author(s):  
Sławomir Prucnal ◽  
Marcin Turek ◽  
Andrzej Drozdziel ◽  
Krzysztof Pyszniak ◽  
Artur Wójtowicz ◽  
...  
Keyword(s):  
Light Emission ◽  
Stoichiometric Composition ◽  
Lattice Relaxation ◽  
Average Diameter ◽  
Lattice Parameter ◽  
Longitudinal Optical ◽  
Quantum Structures ◽  
Phonon Modes ◽  
Relaxation Energy ◽  
Oriented Parallel

AbstractThe InAs quantum structures were formed in silicon by sequential ion implantation and subsequent thermal annealing. Two kinds of crystalline InAs nanostructures were successfully synthesized: nanodots (NDs) and nanopyramids (NPs). The peaks at 215 and 235 cm−1, corresponding to the transverse optical (TO) and longitudinal optical (LO) InAs single-phonon modes, respectively, are clearly visible in the Raman spectra. Moreover, the PL band at around 1.3 µm, due to light emission from InAs NDs with an average diameter 7±2 nm, was observed. The InAs NPs were found only in samples annealed for 20 ms at temperatures ranging from 1000 up to 1200°C. The crystallinity and pyramidal shape of InAs quantum structures were confirmed by HRTEM and XRD techniques. The average size of the NPs is 50 nm base and 50 nm height, and they are oriented parallel to the Si (001) planes. The lattice parameter of the NPs increases from 6.051 to 6.055 Å with the annealing temperature increasing from 1100 to 1200°C, due to lattice relaxation. Energy dispersive spectroscopy (EDS) shows almost stoichiometric composition of the InAs NPs.

Europium-Doped Hydroxyapatite: Influence of Excitation Wavelength on the Eu3+ Luminescence in the Hydroxyapatite

2015 ◽  
Vol 820 ◽  
pp. 335-340 ◽  
Author(s):  
Flávia R.O. Silva ◽  
Nelson B. de Lima ◽  
Deiby S. Gouveia ◽  
Nildemar A.M. Ferreira ◽  
Valter Ussui ◽  
...  
Keyword(s):  
Precipitation Method ◽  
Excitation Wavelength ◽  
Careful Evaluation ◽  
Lanthanide Ion ◽  
Site Occupation ◽  
Different Temperatures ◽  
Co Precipitation ◽  
The Eu

Hydroxyapatite (HA) doped with europium (HAEu) offers the advantage of making the hydroxyapatite a fluorescent biomarker, allowing their imaging through emissionin vivoandin vitrotests. Several authors had been based their studies about europium site occupation (CaI and CaII) in hydroxyapatite by the lanthanide ion luminescence, verifying the influence of the method of synthesis and concentration of the dopant ion. In this study HA nanoparticles doped with 1.4 mol% of trivalent europium were synthesized by co-precipitation method and thermal treated at different temperatures (600°C and 1200°C). A careful evaluation of the influence of the excitation wavelength of europium luminescence in the HAEu was performed and it has been verified that both the characteristics transitions of europium, at CaI and CaII sites, and the luminescent intensity are dependent on the excitation wavelength. The non-observance of this fact can lead to erroneous conclusions about the site occupation of europium in hydroxyapatites.

Effect of Calcination Temperature on Phase Transformation and Microstructure of Al2O3/GdAlO3 Compound Powder Prepared by Co-Precipitation Method

2012 ◽  
Vol 512-515 ◽  
pp. 535-538 ◽  
Author(s):  
Shuai Sun ◽  
Qiang Xu
Keyword(s):  
Calcination Temperature ◽  
Raw Materials ◽  
Metastable Phase ◽  
Precipitation Method ◽  
Calcination Process ◽  
Compound Powder ◽  
Average Grain Size ◽  
Different Temperatures ◽  
Diffraction Peaks ◽  
Co Precipitation

A Coprecipitation Method Was Applied to Synthesize Al2O3/GdAlO3 Compound Powder, Using Ammonia as the Precipitator. Gadolinium Oxide and Aluminium Nitrate Were Used as the Raw Materials with the Eutectic Ratio( 77 mol% Al 3+ – 23 mol% Gd 3+ ). the Precursor Was Calcined at Different Temperatures from 1200 to 1600 °C. the Phase Identifications at Different Temperatures Were Characterized by X-ray Diffractometry (XRD). the Growth Morphology of Particles Were Investigated Using Field Emission Electro Microscopy (FE-SEM). the Results Reveal that GdAlO3 Crystallized Earlier than α-Al2O3. the Diffraction Peaks of α-Al2O3 Phase Were Observed after Calcination at 1300°C for 1 H. Metastable Phase Gd3Al5O12 Underwent Complete Decomposition at 1600°C for 1 H. Gadolinium Aluminate and α-Al2O3 Showed Different Growth Mechanism during the Calcination Process. the Average Grain Size of the Calcined Powder Increased from ~40 to ~900 Nm as the Calcination Temperature Increased from 1200 to 1600 °C.

Light Emission Versus Excitation from Porous Structures in Ion-Implanted Silicon

1994 ◽  
Vol 358 ◽  
Author(s):  
É. Vázsonyi ◽  
I. Barsony ◽  
T. Lohner ◽  
M. Fried ◽  
J. Erostyák ◽  
...  
Keyword(s):  
Doping Level ◽  
Light Emission ◽  
Integral Intensity ◽  
Surface Region ◽  
Peak Position ◽  
Excitation Wavelength ◽  
The Novel ◽  
Mechanical Instability ◽  
Novel Structure ◽  
Silicon Structures

ABSTRACTThe quantum efficiency of electroluminescence (EL) in porous silicon structures (PSL) is practically limited by the mechanical instability of higher porosity layers. This can be overcome by adding a thin implanted p+ surface region before the formation of PSL. The resulting structure consisted of different morphologies depending on the local doping level. When the implantation doping level and diffusion depth was increased, reduced photoluminescence (PL) from the otherwise strongly emitting buried PSL of 80% porosity was obtained. Spectroscopic ellipsometry provided detailed analysis of optical transmission of PSL prepared on a boron implanted substrate. Since the spectral transmission of PSL is morphology dependent, in this novel structure the excitation wavelength can be absorbed in the upper mesoporous p+ region, which is much more transparent for the visible emission spectrum. The width and peak position as well as integral intensity of EL spectra during anodic oxidation of the novel, workable structure were not affected by the doping level in the thin surface region.

Dopant and excitation wavelength dependent color tunability in Dy3+:YVO4 and Dy3+/Eu3+:YVO4 microparticles towards white light emission

2016 ◽  
Vol 45 (41) ◽  
pp. 16231-16239 ◽  
Author(s):  
Anna M. Kaczmarek ◽  
Dorine Ndagsi ◽  
Rik Van Deun
Keyword(s):  
White Light ◽  
Light Emission ◽  
White Light Emission ◽  
Excitation Wavelength ◽  
Emission Color ◽  
Color Tunability

The emission color of Dy:YVO4 and Dy,Eu:YVO4 microstructures could be tuned towards white light and white light with a yellow undertone through varying the Ln3+ doping percentages as well as the excitation wavelengths.

scholarly journals Facile and High-yield Synthesis of N-doped Carbon Quantum Dots from Biomass Quinoa Saponin for the Detection of Co2+

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Cuo Zhou ◽  
Shunwei Wu ◽  
Shenghui Qi ◽  
Weijun Song ◽  
Chunyan Sun
Keyword(s):  
Quantum Dots ◽  
Metal Ion ◽  
Light Emission ◽  
Low Cost ◽  
Carbon Quantum Dots ◽  
High Yield ◽  
Excitation Wavelength ◽  
Uniform Size ◽  
Orthogonal Experiments ◽  
Co2 Detection

Hydrothermal synthesis of carbon quantum dots (CQDs) from natural biomass is a green and sustainable route for CQDs applications in various fields. In this work, the preparation and characterization of CQDs based on quinoa saponin were investigated. The optimum synthetic conditions determined by orthogonal experiments were as follows: 2 g quinoa saponin powder and 0.04 mol ethylenediamine reacted at 200°C for 10 h. The relative fluorescence quantum yield (QY = 22.2%) can be obtained, which is higher than some results reported in the literatures. The prepared CQDs had a small and uniform size (∼2.25 nm) and exhibited excitation wavelength-dependent blue light emission behavior. The CQDs displayed excellent sensitivity for Co2+ detection along with good linear correlation ranging from 20 to 150 µM and the detection limit of 0.49 µM. The CQDs prepared in this experiment were successfully implanted into soybean sprouts for fluorescence imaging. The sprouts could grow healthily even soaked in the CQDs solution for two weeks, demonstrating the low toxicity of the CQDs. The advantages of the CQDs, such as low cost, ease of manufacture, nontoxicity, and stability, have potential applications in many areas such as metal ion detection and biosensing.

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