scholarly journals Оптические свойства кристаллов (ZrO-=SUB=-2-=/SUB=-)-=SUB=-1-x-=/SUB=-(Y-=SUB=-2-=/SUB=-O-=SUB=-3-=/SUB=-)-=SUB=-x-=/SUB=- (x=0-0.037), полученных направленной кристаллизацией расплава

2020 ◽  
Vol 128 (12) ◽  
pp. 1830
Author(s):  
Т.В. Перевалов ◽  
В.Н. Кручинин ◽  
С.В. Рыхлицкий ◽  
В.А. Гриценко ◽  
А.П. Елисеев ◽  
...  
Keyword(s):  
Zirconium Oxide ◽  
Oxygen Vacancies ◽  
Maximum Energy ◽  
Photoluminescence Spectra ◽  
High Concentration ◽  
Green Luminescence ◽  
Monoclinic Zro2 ◽  
Tetragonal Modification ◽  
Properties Of Materials ◽  
Optical Properties Of Materials

The luminescent and optical properties of materials based on zirconium oxide obtained by the crystallization of ZrO2 with 0, 2.0, 2.5, 2.8, and 3.7% mol Y2O3 melts were studied. Using Raman spectroscopy, it was found that when the Y2O3 content in the mixture is less than 2 % mol. the material is predominantly a monoclinic ZrO2 structure. For such crystal, a blue-green band with the maximum energy of 2.4 eV was observed in the photoluminescence spectra. This fact, together with the peculiarities of the refractive index and absorption dispersion spectra, indicates the presence of a high concentration of oxygen vacancies and polyvacancies in the sample. With a higher content of Y2O3 in the mixture, the tetragonal modification of ZrO2 dominates in the studied materials; the intensity of blue-green luminescence decreases. A comparative analysis of experimental optical spectra with the first-principle calculations for ideal ZrO2 crystals in the cubic, tetragonal and monoclinic phases was performed.

Oxygen Vacancies in Zirconium Oxide as the Blue Luminescence Centers and Traps Responsible for Charge Transport

2020 ◽  
Author(s):  
Damir R. Islamov ◽  
Vladimir A. Gritsenko ◽  
Timofey V. Perevalov ◽  
Vladimir Sh. Aliev ◽  
Alexander P. Yelisseyev ◽  
...  
Keyword(s):  
Charge Transport ◽  
Zirconium Oxide ◽  
Oxygen Vacancies ◽  
Blue Luminescence ◽  
Luminescence Centers

Fluorescent Nanotechnology: An Evolution in Optical Sensors

2020 ◽  
Vol 17 ◽  
Author(s):  
Dilawar Hassan ◽  
Hadi Bakhsh ◽  
Asif M. Khurram ◽  
Shakeel A. Bhutto ◽  
Nida S. Jalbani ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Sensors ◽  
Light Emission ◽  
Environmental Contaminants ◽  
Fluorescent Nanoparticles ◽  
Sensing Applications ◽  
Properties Of Materials ◽  
Optical Properties Of Materials ◽  
Fluorescent Nanomaterials

Background: The optical properties of nanomaterials have evolved enormously with the introduction of nanotechnology. The property of materials to absorb and/or emit specific wavelength has turned them into one of the most favourite candidates to be effectively utilized in different sensing applications e.g organic light emission diodes (OLEDs) sensors, gas sensors, biosensors and fluorescent sensors. These materials have been reported as a sensor in the field of tissue and cell imaging, cancer detection and detection of environmental contaminants etc. Fluorescent nanomaterials are heling in rapid and timely detection of various contaminants that greatly impact the quality of life and food, that is exposed to these contaminants. Later, all the contaminants have been investigated to be most perilous entities that momentously affect the life span of the animals and humans who use those foods which have been contaminated. Objective: In this review, we will discuss about various methods and approaches to synthesize the fluorescent nanoparticles and quantum dots (QDs) and their applications in various fields. The application will include the detection of various environmental contaminants and bio-medical applications. We will discuss the possible mode of action of the nanoparticles when used as sensor for the environmental contaminants as well as the surface modification of some fluorescent nanomaterials with anti-body and enzyme for specific detection in animal kingdom. We will also describe some RAMAN based sensors as well as some optical sensing-based nanosensors. Conclusion: Nanotechnology has enabled to play with the size, shape and morphology of materials in the nanoscale. The physical, chemical and optical properties of materials change dramatically when they are reduced to nanoscale. The optical properties can become choosy in terms of emission or absorption of wavelength in the size range and can result in production of very sensitive optical sensor. The results show that the use of fluorescent nanomaterials for the sensing purposes are helping a great deal in the sensing field.

scholarly journals Highly Dispersed Pd Species Supported on CeO2 Catalyst for Lean Methane Combustion: The Effect of the Occurrence State of Surface Pd Species on the Catalytic Activity

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 772
Author(s):  
Yanxiong Liu ◽  
Changhua Hu ◽  
Longchun Bian
Keyword(s):  
Catalytic Activity ◽  
Oxygen Vacancies ◽  
Methane Combustion ◽  
Pd Nanoparticles ◽  
High Concentration ◽  
Ch4 Combustion ◽  
Highly Active ◽  
Δ Phase ◽  
Occurrence State ◽  
Comprehensive Characterization

The correlation between the occurrence state of surface Pd species of Pd/CeO2 for lean CH4 combustion is investigated. Herein, by using a reduction-deposition method, we have synthesized a highly active 0.5% PdO/CeO2-RE catalyst, in which the Pd nanoparticles are evenly dispersed on the CeO2 nanorods CeO2-R. Based on comprehensive characterization, we have revealed that the uniformly dispersed Pd nanoparticles with a particle size distribution of 2.3 ± 0.6 nm are responsible for the generation of PdO and PdxCe1−xO2−δ phase with –Pd2+–O2−–Ce4+– linkage, which can easily provide oxygen vacancies and facilitate the transfer of reactive oxygen species between the CeO2-R and Pd species. As a consequence, the remarkable catalytic activity of 0.5% Pd/CeO2-RE is related to the high concentration of PdO species on the surface of the catalyst and the synergistic interaction between the Pd species and the CeO2 nanorod.

C-axis preferentially oriented and fully activated TiO2 nanotube arrays for lithium ion batteries and supercapacitors

2014 ◽  
Vol 2 (29) ◽  
pp. 11454-11464 ◽  
Author(s):  
Dengyu Pan ◽  
He Huang ◽  
Xueyuan Wang ◽  
Liang Wang ◽  
Haobo Liao ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Ethylene Glycol ◽  
Lithium Ion Batteries ◽  
Oxygen Vacancies ◽  
Lithium Ion ◽  
Tio2 Nanotube Arrays ◽  
Nanotube Arrays ◽  
High Concentration ◽  
Oxygen Conditions ◽  
Titanium Dioxide Nanotube Arrays

We report the fabrication of long titanium dioxide nanotube arrays with highly c-axis preferentially oriented crystallization and a high concentration of oxygen vacancies by second anodization in ethylene glycol and annealing under poor-oxygen conditions.

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