Solvothermal Synthesis and Near-Infrared Shielding Properties of Cs0.3WO3/WO3 Composites

2020 ◽  
Vol 19 (04) ◽  
pp. 1950032
Author(s):  
Zhao Linyuan ◽  
Yang Mingqing ◽  
Lv Yong
Keyword(s):  
Electron Microscopy ◽  
Near Infrared ◽  
Raw Materials ◽  
Tungsten Bronze ◽  
Tungstic Acid ◽  
Light Transmittance ◽  
Infrared Light ◽  
Transmission Electron ◽  
Shielding Properties ◽  
Electron Energy Loss

The Cs[Formula: see text]WO3/WO3 composite with near-infrared shielding properties was synthesized by the solvothermal method using tungstic acid and cesium salt as raw materials. The as-prepared composites were tested by X-ray powder diffraction, scanning electron microscopy, energy spectrum analysis, transmission electron microscopy, electron energy loss spectroscopy, and ultraviolet-visible near-infrared spectroscopy. The effects of different reaction conditions on the structure and near-infrared shielding properties of the synthesized composites were investigated. The best near-infrared light transmittance of as-prepared composites can reach up to 9%, which provides a feasible solution for the near-infrared shielding material. The new homogeneous composites of cesium tungsten bronze and tungsten oxide are good candidates for solar filters.

Effects of Annealing in Different Atmosphere on the Near-Infrared Shielding Properties of CsxWO3 Particles

2013 ◽  
Vol 712-715 ◽  
pp. 284-287 ◽  
Author(s):  
Qiang Xu ◽  
Jing Xiao Liu ◽  
Fei Shi ◽  
Jia Yu Luo ◽  
Yan Yan Jiang ◽  
...  
Keyword(s):  
Near Infrared ◽  
Hydrothermal Reaction ◽  
Raw Materials ◽  
Tungsten Bronze ◽  
Carbon Powder ◽  
X Ray Diffraction ◽  
Air Atmosphere ◽  
Light Region ◽  
Apparent Decrease ◽  
Shielding Properties

Using sodium tungstate and cesium carbonate as raw materials, cesium tungsten bronze (CsxWO3) powders were synthesized by low temperature hydrothermal reaction with citric acid as the reducing agent. Effects of annealing in different atmosphere on the near-infrared shielding properties of CsxWO3were investigated. The microstructure of CsxWO3powders was characterized by X-ray diffraction. The CsxWO3films were prepared on glass using polyvinyl alcohol solution as film-forming agent, and the optical transmission properties of CsxWO3films were investigated. The results indicate that the near-infrared shielding ability of samples after annealed at 200°C in the air atmosphere did not deteriorate apparently, but the 400°C-annealed samples in the air atmosphere showed apparent decrease of near-infrared shielding properties. Annealing in the carbon powder atmosphere had no apparent effects on the properties of CsxWO3particles. As for the N2annealing, the 500°C-annealed samples showed best improved near-infrared shielding as well as high transparency in the visible light region.

scholarly journals Up-Conversion Nanomaterial Doped With Au Nanoparticles With Photothermal Conversion for Multi-Modality Imaging

2021 ◽  
Author(s):  
Wei Zhang ◽  
Yanli Lu ◽  
Yang Zang ◽  
Qingyun Xiong ◽  
Jinping Xiong
Keyword(s):  
Electron Microscopy ◽  
Gold Nanoparticles ◽  
Near Infrared ◽  
Au Nanoparticles ◽  
Cell Counting ◽  
Infrared Light ◽  
Transmission Electron ◽  
Before And After ◽  
Low Cytotoxicity ◽  
Magnetic Resonance Imaging Mri

In this study, a new method for synthesizing Au-NaYF4:Yb3+/Er3+-DSPE-PEG2K nanocomposites was introduced. Using a hydrothermal method, the synthesized Yb3+- and Er3+-codoped NaYF4 upconversion luminescent materials and Au nanoparticles were doped into upconversion nanomaterials and modified with DSPE-PEG2k up-conversion nanomaterials. This material is known as Ag-UCNPs-DSPE-PEG2k, it improves both the luminous intensity because of the doped Au nanoparticles and has low cytotoxicity because of the DSPE-PEG2k modified. Exciting UCNPs with a wavelength of 980nm near-infrared light will emit light with a wavelength of 520nm to further excite gold nanoparticles to convert light energy into heat. Successful synthesized gold nanoparticles was confirmed using transmission electron microscopy (TEM). The morphology of UCNPs was observed using scanning electron microscopy (SEM), and the mapping confirmed the successful doping of Au nanoparticles. Fluorescence spectra were used to compare changes in luminescence intensity before and after doping Au nanoparticles. The cytotoxicity of Au-UCNPs-DSPE-PEG2K was tested via the cell counting kit-8 (CCK-8) method, and its imaging ability was characterized using the Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) method.

Hydrothermal Synthesis of Cesium Tungsten Bronze and its Heat Insulation Properties

2012 ◽  
Vol 531 ◽  
pp. 235-239 ◽  
Author(s):  
Jing Xiao Liu ◽  
Xiao Jie Wang ◽  
Fei Shi ◽  
Zhan Jun Peng ◽  
Jia Yu Luo ◽  
...  
Keyword(s):  
Near Infrared ◽  
Sodium Tungstate ◽  
Heat Insulation ◽  
Hydrothermal Reaction ◽  
Raw Materials ◽  
Tungsten Bronze ◽  
Precursor Solution ◽  
Dispersing Agent ◽  
Insulation Effect ◽  
Shielding Properties

Using sodium tungstate and cesium carbonate as raw materials, cesium tungsten bronze (CsxWO3) powders were synthesized by low temperature hydrothermal reaction with citric acid as the reducing agent. The CsxWO3 films were prepared on glass using polyvinyl alcohol solution as dispersing agent. The microstructure and morphology of CsxWO3 powders were characterized by XRD and SEM, and the optical spectra and heat insulation properties of CsxWO3 powder and films were investigated. The results indicate that the synthesized cesium tungsten bronze powders have hexagonal Cs0.32WO3 crystal structure. The as-prepared CsxWO3 powder and films show strong near-infrared absorption and near-infrared shielding properties. Furthermore, the near-infrared shielding performance of glass coated with CsxWO3 film has been further improved after UV irradiation. Especially, the glasses coated with CsxWO3 films which was synthesized from the non-ethanol precursor solution exhibit most outstanding near-infrared shielding performance and best heat insulation effect. In comparison with the blank glass without CsxWO3 film, the heat insulation temperature difference can achieve 24.8°C.

Investigation of Switching Mechanism in HfO2-Based Oxide Resistive Memories by In-Situ Transmission Electron Microscopy and Electron Energy Loss Spectroscopy

2017 ◽  
Author(s):  
T. Dewolf ◽  
D. Cooper ◽  
N. Bernier ◽  
V. Delaye ◽  
A. Grenier ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Energy Loss ◽  
Electron Energy ◽  
Electron Energy Loss Spectroscopy ◽  
Hafnium Dioxide ◽  
Switching Mechanism ◽  
Transmission Electron ◽  
Electron Energy Loss

Abstract Forming and breaking a nanometer-sized conductive area are commonly accepted as the physical phenomenon involved in the switching mechanism of oxide resistive random access memories (OxRRAM). This study investigates a state-of-the-art OxRRAM device by in-situ transmission electron microscopy (TEM). Combining high spatial resolution obtained with a very small probe scanned over the area of interest of the sample and chemical analyses with electron energy loss spectroscopy, the local chemical state of the device can be compared before and after applying an electrical bias. This in-situ approach allows simultaneous TEM observation and memory cell operation. After the in-situ forming, a filamentary migration of titanium within the dielectric hafnium dioxide layer has been evidenced. This migration may be at the origin of the conductive path responsible for the low and high resistive states of the memory.

Intergrowth of niobium tungsten oxides of the tetragonal tungsten bronze type

2020 ◽  
Vol 75 (11) ◽  
pp. 913-919
Author(s):  
Frank Krumeich
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Tungsten Bronze ◽  
Structural Complexity ◽  
Dark Field ◽  
Tetragonal Tungsten Bronze ◽  
Tungsten Oxides ◽  
Transmission Electron ◽  
Scanning Transmission

AbstractSince the 1970s, high-resolution transmission electron microscopy (HRTEM) is well established as the most appropriate method to explore the structural complexity of niobium tungsten oxides. Today, scanning transmission electron microscopy (STEM) represents an important alternative for performing the structural characterization of such oxides. STEM images recorded with a high-angle annular dark field (HAADF) detector provide not only information about the cation positions but also about the distribution of niobium and tungsten as the intensity is directly correlated to the local scattering potential. The applicability of this method is demonstrated here for the characterization of the real structure of Nb7W10O47.5. This sample contains well-ordered domains of Nb8W9O47 and Nb4W7O31 besides little ordered areas according to HRTEM results. Structural models for Nb4W7O31 and twinning occurring in this phase have been derived from the interpretation of HAADF-STEM images. A remarkable grain boundary between well-ordered domains of Nb4W7O31 and Nb8W9O47 has been found that contains one-dimensionally periodic features. Furthermore, short-range order observed in less ordered areas could be attributed to an intimate intergrowth of small sections of different tetragonal tungsten bronze (TTB) based structures.

Near-Infrared Light Emission from of Er-Doped ZnO Thin Film in Micropits Processed on Si Substrate

2006 ◽  
Vol 320 ◽  
pp. 113-116
Author(s):  
Shigeru Tanaka ◽  
Yukari Ishikawa ◽  
Naoki Ohashi ◽  
Junichi Niitsuma ◽  
Takashi Sekiguchi ◽  
...  
Keyword(s):  
Thin Film ◽  
Near Infrared ◽  
Light Emission ◽  
Infrared Light ◽  
Zno Thin Film ◽  
Si Substrate ◽  
Near Infrared Light ◽  
Transmission Electron ◽  
Doped Zno ◽  
Er Doped

We have obtained Er-doped ZnO thin film in a micropattern of reverse trapezoids processed on Si substrate by sputtering and ultrafine polishing techniques. Near-infrared light emission was detected successfully from the thin film filling a single micropit with 10 μm square. Transmission electron microscopy (TEM) observation showed epitaxial growth of ZnO crystals along the curvature of the micropit.

scholarly journals Non-Graphitizing Carbon: Its Structure and Formation from Organic Precursors

2019 ◽  
Vol 21 (3) ◽  
pp. 227 ◽  
Author(s):  
P.J.F. Harris
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Present Author ◽  
Precursor Chemistry ◽  
Microporous Structure ◽  
Transmission Electron ◽  
Carbon Networks ◽  
Organic Precursors ◽  
Electron Energy Loss ◽  
Carbon Network

Non-graphitizing carbon, or char, has been intensively studied for decades, but there is still no agreement about its detailed atomic structure. The first models for graphitizing and non-graphitizing carbons were proposed by Rosalind Franklin in the early 1950s, and while these are correct in a broad sense, they are incomplete. Subsequent models also fail to explain fully the structure of non-graphitizing carbons. The discovery of the fullerenes and related structures stimulated the present author and others to put forward models which incorporate non-hexagonal rings into hexagonally-bonded sp2 carbon networks, creating a microporous structure made up of highly curved fragments. However, this model has not been universally accepted. This paper reviews the models that have been put forward for non-graphitizing carbon and outlines the evidence for a fullerene-like structure. This evidence comes from transmission electron microscopy, electron energy loss spectroscopy and Raman spectroscopy. Finally, the influence of precursor chemistry on the structure of graphitizing and non-graphitizing carbons is discussed. It is well established that carbonization of oxygen–containing precursors tends to produce non-graphitizing carbons. This may be explained by the fact that the removal of oxygen from a hexagonal carbon network can result in the formation of pentagonal carbon rings.

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