Optical properties of undoped, Eu3+ doped and Li+ co-doped Y2Hf2O7 nanoparticles and polymer nanocomposite films

2020 ◽  
Vol 7 (2) ◽  
pp. 505-518 ◽  
Author(s):  
Santosh K. Gupta ◽  
Jose P. Zuniga ◽  
Maya Abdou ◽  
P. S. Ghosh ◽  
Yuanbing Mao
Keyword(s):  
Optical Properties ◽  
Quantum Yield ◽  
Polymer Nanocomposite ◽  
Nanocomposite Films ◽  
Asymmetry Ratio ◽  
Covalent Character ◽  
Co Doping ◽  
Concentration Asymmetry ◽  
Co Doped

Li+ co-doping of Y2Hf2O7:Eu3+ nanoparticles improve their quenching concentration, asymmetry ratio, quantum yield, and radioluminescence intensity due to the enhanced covalent character of Eu3+–O2− bonding.

Charge compensation in RE3+ (RE = Eu, Gd) and M+ (M = Li, Na, K) co-doped alkaline earth nanofluorides obtained by microwave reaction with reactive ionic liquids leading to improved optical properties

2014 ◽  
Vol 2 (44) ◽  
pp. 9439-9450 ◽  
Author(s):  
C. Lorbeer ◽  
F. Behrends ◽  
J. Cybinska ◽  
H. Eckert ◽  
A.-V. Mudring
Keyword(s):  
Optical Properties ◽  
Ionic Liquids ◽  
Quantum Yield ◽  
Alkaline Earth ◽  
Charge Compensation ◽  
Luminescent Material ◽  
Microwave Reaction ◽  
Co Doped

Careful charge compensation in doubly doped alkaline earth nanofluorides enables a luminescent material with 199% quantum yield.

Bandgap control and optical properties of β-Si3N4 by single- and co-doping from a first-principles simulation

2018 ◽  
Vol 32 (14) ◽  
pp. 1850178 ◽  
Author(s):  
Xuefeng Lu ◽  
Xu Gao ◽  
Junqiang Ren ◽  
Cuixia Li ◽  
Xin Guo ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Optical Properties ◽  
First Principles ◽  
Density Functional ◽  
Formation Energy ◽  
Blue Shift ◽  
Functional Theory ◽  
Co Doping ◽  
Charge Density Difference ◽  
Co Doped

Bandgap tailoring of [Formula: see text]-Si3N4 is performed by single and co-doping by using density functional theory (DFT) of PBE functional and plane-wave pseudopotential method. The results reveal that a direct bandgap transfers into an indirect one when single-doped with As element. Also, a considerate decrease of bandgap to 0.221 eV and 0.315 eV is present for Al–P and As–P co-doped systems, respectively, exhibiting a representative semiconductor property that is characteristic for a narrower bandgap. Compared with other doped systems, Al-doped system with formation energy of 2.67 eV is present for a more stable structure. From charge density difference (CDD) maps, it is found that the blue area between co-doped atoms increases, illustrating an enhancement of covalent property for Al–P and Al–As bonds. Moreover, a slightly obvious “Blue shift” phenomenon can be obtained in Al, Al–P and Al–As doped systems, indicating an enhanced capacity of responses to light, which contributes to the insight for broader applications with regard to photoelectric devices.

scholarly journals Structural, Magnetic and Optical Properties of Gd and Co Co-Doped YFeO3 Nanopowders

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2423 ◽  
Author(s):  
Meng Wang ◽  
Ting Wang
Keyword(s):  
Optical Properties ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Ferromagnetic Behavior ◽  
X Ray Diffraction ◽  
Optical Fields ◽  
Solid State Reaction Technique ◽  
Co Doping ◽  
Distorted Structure ◽  
Co Doped

YFeO3, YFe0.95Co0.05O3, Y0.95Gd0.05FeO3 and Y1−xGdxFe0.95Co0.05O3 (x = 0.0, 0.05, 0.10, 0.15 and 0.20) nanopowders were successfully fabricated via a low-temperature solid-state reaction technique. Results obtained using X-ray diffraction (XRD), scanning electron microscopy (SEM), and Raman spectra indicate that YFeO3 nanopowders with Gd3+ and Co3+ ions co-doping at Y and Fe-sites were fabricated at 800 °C in sizes below 50 nm, and a distorted structure was obtained. Magnetic hysteresis loop analyses illustrate that ferromagnetic behavior of YFeO3 nanopowders can be enhanced with the addition of Gd and Co. Whereas the maximum and remnant magnetization of the powders were found to be about 5.24 and 2.6 emu/g, respectively, the optical band gap was around 2.4 eV, proving that co-doped YFeO3 nanopowders have a strong capability to absorb visible light. Because both magnetic and optical properties of these materials are greatly improved with the addition of Gd and Co, one can expect the scope of their potential application in the magnetic and optical fields to increase.

Effective blue-violet photoluminescence through lanthanum and fluorine ions co-doping for CsPbCl3 perovskite quantum dots

Nanoscale ◽  
2019 ◽  
Vol 11 (5) ◽  
pp. 2484-2491 ◽  
Author(s):  
Yue Zhai ◽  
Xue Bai ◽  
Gencai Pan ◽  
Jinyang Zhu ◽  
He Shao ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Quantum Yield ◽  
Feasible Method ◽  
Co Doping ◽  
Photoluminescence Quantum Yield ◽  
Perovskite Quantum Dots ◽  
Fluorine Ions

Co-doping of cation (La3+) and anion (F−) ions is a feasible method to improve the optical properties of CsPbCl3 QDs, and high photoluminescence quantum yield of 36.5% is achieved in CsPb(Cl0.7F0.3)3:La3+ QDs.

scholarly journals Tailoring Blue-Green Double Emissions in Carbon Quantum Dots via Co-Doping Engineering by Competition Mechanism between Chlorine-Related States and Conjugated π-Domains

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 635 ◽  
Author(s):  
Xue Sun ◽  
Huilian Liu ◽  
Lili Yang ◽  
Xinying Wang ◽  
Weiqiang Yang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Reaction Time ◽  
Quantum Confinement ◽  
Quantum Confinement Effect ◽  
Carbon Quantum Dots ◽  
Confinement Effect ◽  
Co Doping ◽  
Photoelectric Properties ◽  
Co Doped

Representing single-layer to tens of layers of graphene in a size less than 30 nm, carbon quantum dots (CQDs) is becoming an advanced multifunctional material for its unique optical, electronic, spin and photoelectric properties induced by the quantum confinement effect and edge effect. In present work, upon co-doping engineering, nitrogen and chlorine co-doped CQDs with uniquely strong blue-green double emissions are developed via a facile and one-pot hydrothermal method. The crystalline and optical properties of CQDs have been well manipulated by tuning the mole ratio of nitrogen/chlorine and the reaction time. The characteristic green emission centered at 512 nm has been verified, originating from the chlorine-related states, the other blue emissions centered at 460 nm are attributed to the conjugated π-domain. Increasing the proportion of 1,2,4-benzentriamine dihydrochloride can effectively adjust the bandgap of CQDs, mainly caused by the synergy and competition of chlorine-related states and the conjugated π-domain. Prolonging the reaction time promotes more nitrogen and chlorine dopants incorporate into CQDs, which inhibits the growth of CQDs to reduce the average size of CQDs down to 1.5 nm, so that the quantum confinement effect dominates into play. This work not only provides a candidate with excellent optical properties for heteroatoms-doped carbon materials but also benefits to stimulate the intensive studies for co-doped carbon with chlorine as one of new dopants paradigm.

Synthesis Structural and Optical Properties of CMC/MgO Nanocomposites

2021 ◽  
Vol 1039 ◽  
pp. 104-114
Author(s):  
Yaqoob M. Jawad ◽  
Mahasin F. Hadi Al-Kadhemy ◽  
Jehan Abdul Sattar Salman
Keyword(s):  
Optical Properties ◽  
Energy Gap ◽  
Experimental Studies ◽  
Polymer Nanocomposite ◽  
Nanocomposite Films ◽  
Structural And Optical Properties ◽  
Covalent Bonds ◽  
Magnesium Oxide Nanoparticles ◽  
Xrd Study ◽  
Method Of Solution

Nanocomposites were prepared by the method of solution casting with different proportions of magnesium oxide nanoparticles (0, 1, 3, 5, 7 and 9) wt%. The structural and optical properties of nanocomposites of CMC/MgO have been studied. It was well known that the increased content of MgONPs in the method contributes to the peaks of MgONPs being completely integrated and/or disappearing within the CMC diffraction halos in the experimental results of XRD study. The differences in the XRD spectrum indicate that doping with nanoparticles induced a disparity in the microstructure of the polymer. Nanocomposite film scanning electron microscopy (SEM) reveals that MgONPs appear to form aggregates and scatter well in (CMC/MgO) nanocomposite films and at apply 9 wt. It forms a continuous network within the polymer for the percentage of MgONPs to (CMC) polymer. FTIR spectrum revealed the MgONPs has no destructive influence on the polymer structure as no covalent bonds formed between CMC and MgONPs. The optical properties of CMC/MgO nanocomposites were measured in wavelength range (200–900) nm. Experimental studies have shown that the absorbance, absorption coefficient, extinction coefficient, refractive index, actual and imaginary dielectric constant of CMC polymer is improved with an increase in concentrations of MgONPs in nanocomposites. The transmittance and energy gap of CMC polymer are decreased with the increase in the concentrations of MgONPs.

Graphene oxide co-doped with dielectric and magnetic phases as an electromagnetic wave suppressor

2017 ◽  
Vol 1 (6) ◽  
pp. 1229-1244 ◽  
Author(s):  
Sourav Biswas ◽  
Yudhajit Bhattacharjee ◽  
Sujit Sankar Panja ◽  
Suryasarathi Bose
Keyword(s):  
Graphene Oxide ◽  
Electromagnetic Wave ◽  
Sandwich Structure ◽  
Polymer Nanocomposite ◽  
Nanocomposite Films ◽  
Magnetic Phases ◽  
Co Doped

The fabrication of thin multilayer polymer nanocomposite films and their judicious arrangement in a sandwich structure to attenuate incoming electromagnetic (EM) radiation, mostly by absorption, is discussed herein.

scholarly journals First-principles Calculation of the Electronic Structure and Optical Properties of ZnO Co-doped with Nb and Ta

2019 ◽  
Vol 25 (3) ◽  
pp. 238-245 ◽  
Author(s):  
Jinpeng WANG ◽  
Tao SHEN ◽  
Hongchen LIU
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
First Principles ◽  
First Principles Calculation ◽  
Ultraviolet Region ◽  
First Principle ◽  
Co Doping ◽  
First Principle Calculations ◽  
Function Loss ◽  
Co Doped

First-principle calculations have been performed to investigate the electronic structure and optical properties of ZnO co-doped with Nb and Ta. The three doping structures are set to: Zn0.9375Nb0.0625O, Zn0.9375Ta0.0625O and Zn0.875Nb0.0625Ta0.0625O. The experiments show that co-doping with Nb and Ta narrows the band gap. And it causes the Fermi level to shift upwards and enter the conduction band, while enhancing the conductivity of the doped system. In addition, it has been determined that the dielectric imaginary part of the dopant system is larger than that of the pure ZnO in the low energy region. The absorption side of the dopant system, on the other hand, exhibits a redshift. Furthermore, the transmittance of the ultraviolet region is significantly increased, and the function loss spectrum appears to redshift. This will provide a good theoretical basis for the study and the applications of photoelectric materials co-doped with Nb and Ta. DOI: http://dx.doi.org/10.5755/j01.ms.25.3.19956

Nitrogen and sulfur co-doped carbon dots with strong blue luminescence

Nanoscale ◽  
2014 ◽  
Vol 6 (22) ◽  
pp. 13817-13823 ◽  
Author(s):  
Hui Ding ◽  
Ji-Shi Wei ◽  
Huan-Ming Xiong
Keyword(s):  
Optical Properties ◽  
Carbon Dots ◽  
Cell Imaging ◽  
Blue Luminescence ◽  
Co Doping ◽  
Doped Carbon Dots ◽  
Co Doped

The optical properties of carbon dots are improved synergistically by co-doping nitrogen and sulfur, which renders excellent performances in cell imaging and Fe3+detection.

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