scholarly journals Intense Red Upconversion Emission and Shape Controlled Synthesis of Gd2O3:Yb/Er Nanocrystals

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Zhigao Yi ◽  
Boyun Wen ◽  
Chao Qian ◽  
Haibo Wang ◽  
Ling Rao ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Upconversion Luminescence ◽  
Upconversion Emission ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Shape Controlled

Yb/Er codoped Gd(OH)3was synthesized firstly via a simple hydrothermal treatment of the corresponding nitrate in the presence of alkali by tuning the pH values. The Gd2O3:Yb/Er nanocrystals were obtained via sintering the corresponding hydroxides precursors. The as-prepared samples were characterized by the typical X-ray diffraction, energy-dispersive X-ray spectroscopy, transmission electron microscopy (TEM), high-resolution TEM, and spectrophotometer. The results revealed that two shapes of the as-prepared Gd2O3:Yb/Er nanocrystals can be readily tuned from lemon-like particle to rod-like structure via tuning pH values from 7 to 14. Moreover, compared with the samples prepared at pH 7, the Gd2O3:Yb/Er nanocrystals prepared at pH 14 exhibit enhanced red upconversion emission and higher upconversion luminescence intensity under the excitation of 980 nm laser.

Shape-Controlled Synthesis of Polypyrrole/Ag Nanostructures in the Presence of Chitosan

2008 ◽  
Vol 8 (1) ◽  
pp. 443-447 ◽  
Author(s):  
Xiaomiao Feng ◽  
Haiping Huang ◽  
Lin Xu ◽  
Jun-Jie Zhu ◽  
Wenhua Hou
Keyword(s):  
Electron Microscopy ◽  
Controlled Synthesis ◽  
Synthetic Route ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Pyrrole Monomer ◽  
Inorganic Nanocomposites ◽  
Shape Controlled ◽  
Scanning Electron

Polypyrrole (PPy)-coated Ag nanoparticles and nanowires were fabricated through the redox reaction between pyrrole monomer and silver nitrate in the presence of chitosan. The morphologies, compositions, and electrochemical activities of PPy/Ag composites were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, and Cyclic voltammetry. The synthetic route employed here is simple and inexpensive and can be extended to prepare other conducting polymer/inorganic nanocomposites.

Enhanced Red Upconversion Luminescence in Yb–Er Codoped NaYF4 Nanocrystals

2016 ◽  
Vol 16 (4) ◽  
pp. 3961-3964
Author(s):  
Weiye Song ◽  
Xueqing Bi ◽  
Xingyuan Guo ◽  
Shushen Liu ◽  
Weiping Qin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Upconversion Luminescence ◽  
Decomposition Reaction ◽  
Energy Transfer Mechanism ◽  
X Ray Diffraction ◽  
Reaction Method ◽  
X Ray ◽  
Transmission Electron ◽  
Temperature Decomposition

In this work the effects of NaYF4:Yb, Er (NYE) structure on the enhanced red upconversion luminescence (UC) was investigated. -NYE nanocrystals (NCs) and -NYE NCs were fabricated by a high temperature decomposition reaction method. The prepared NCs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy. The results show that the red UC luminescence of -NYE NCs is significantly enhanced compared with that of -NYE. Furthermore, a possible energy transfer mechanism was proposed on the basis of our experimental results.

Upconversion Luminescence Properties of NaYF4 Nanocrystals Precipitated Nd3+/Yb3+/Ho3+ Tri-Doped Oxyfluoride Glass Ceramics

2016 ◽  
Vol 16 (4) ◽  
pp. 3744-3748 ◽  
Author(s):  
Yuan Gao ◽  
Yuebo Hu ◽  
Dacheng Zhou ◽  
Jianbei Qiu
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Energy Transfer Process ◽  
Upconversion Luminescence ◽  
Glass Ceramics ◽  
X Ray Diffraction ◽  
Oxyfluoride Glass ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix

Transparent oxyflouride glass ceramics composed of SiO2–Al2O3–Na2O–NaF–YF3 tri-coped with Nd3+/Yb3+/Ho3+ were prepared by thermal treatment. Segregation of NaYF4 nanocrystals in the matrix was confirmed from structural analysis by means of X-ray diffraction and transmission electron microscopy. Compared with glass samples, very strong green upconversion (UC) luminescence due to the Ho3+:(4F5, 5S2)→5I8 transition was observed in the glass ceramics under 808 nm excitation. It was found that upconversion intensity of Ho3+ strongly depends on the Nd3+ concentration, and the energy transfer process from Nd3+ to Ho3+ via Yb3+ was proposed.

Controlled Synthesis of BaF2 Nanorods via Hydrothermal Microemulsion Method

2007 ◽  
Vol 121-123 ◽  
pp. 441-444
Author(s):  
Y.C. Chen ◽  
Y.G. Zhang
Keyword(s):  
Electron Microscopy ◽  
Raw Materials ◽  
Barium Chloride ◽  
Building Blocks ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
Microemulsion Method ◽  
X Ray ◽  
Transmission Electron ◽  
Microemulsion Droplet

BaF2 nanorods were synthesized by hydrothermal microemulsion method using sodium fluoride (NaF) and barium chloride (BaCl2) as the raw materials. The as-prepared products were characterized by powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The results showed that the products were composed of BaF2 nanorods with diameters of 18-62 nm and lengths up to 1μm. A directed aggregation growth process mediated by the microemulsion droplet building blocks is proposed for the formation of BaF2 nanorods. Further work is in progress to evaluate the possibility of synthesizing other fluoride 1D nanostructures using a similar method.

Uniform Cerium-Based Coordination Polymer Microspheres: Preparation and Upconversion Emission

2016 ◽  
Vol 16 (4) ◽  
pp. 3705-3709 ◽  
Author(s):  
Zhi-Wen Nie ◽  
Cheng-Hui Zeng ◽  
Gang Xie ◽  
Sheng-Liang Zhong
Keyword(s):  
Electron Microscopy ◽  
Coordination Polymer ◽  
Large Scale ◽  
Upconversion Emission ◽  
X Ray Diffraction ◽  
X Ray ◽  
Band Emission ◽  
Transmission Electron ◽  
Light Excitation ◽  
Luminescent Spectra

Homogeneously doped Yb3+ and Er3+ cerium-based coordination polymer (CP) microspheres have been successfully synthesized on a large scale through a simple solvothermal route with 2, 5-pyridinedicarboxylic acid (2, 5-H2PDC) as the organic linker. CeO2:Yb3+, Er3+ porous microspheres were obtained by annealing the corresponding CP microspheres at 600 °C for 4 h under atmospheric pressure. These as-prepared products were characterized by Powder X-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), energy-dispersion X-ray (EDX) spectroscopy, Thermogravimetric (TG) and derivative thermogravimetric (DTG) analysis. The room temperature upconversion luminescent spectra of the as-prepared microspheres were carried out by 980 nm NIR light excitation. Interestingly, Yb3+ and Er3+ codoped CP microspheres give a single-band emission centered at 673 nm, while the CeO2:Yb3+, Er3+ microspheres give emission in green and red region, with red being the dominant emission. The emission intensity of the CeO2:Yb3+, Er3+ microspheres were much stronger than that of the Yb3+ and Er3+ codoped CP microspheres.

Synthesis and upconversion luminescence properties of CaF2:Yb3+,Er3+ nanoparticles obtained from SBA-15 template

2010 ◽  
Vol 25 (10) ◽  
pp. 2035-2041 ◽  
Author(s):  
Zhiguo Xia ◽  
Peng Du
Keyword(s):  
Electron Microscopy ◽  
Upconversion Luminescence ◽  
Emission Spectra ◽  
Average Diameter ◽  
Cubic Phase ◽  
Pumping Power ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Transmission Electron

CaF2:Yb3+,Er3+ upconversion (UC) luminescence nanoparticles have been synthesized using mesoporous silica (SBA-15) as a hard template. The samples were characterized by x-ray diffraction, Fourier transform infrared spectra, field-emission scanning electron microscopy, transmission electron microscopy, and UC emission spectra, respectively. Highly crystalline cubic phase CaF2:Yb3+,Er3+ nanoparticles are uniformly distributed with an average diameter of about 40–50 nm, and the formation process is also demonstrated. The UC fluorescence has been realized in the as-prepared CaF2:Yb3+,Er3+ nanoparticles on 980-nm excitation. The UC emission transitions for 4F9/2–4I15/2 (red), 2H11/2–4I15/2 (green), 4S3/2–4I15/2 (green), and 2H9/2–4I15/2 (violet) in the Yb3+/Er3+ codoped CaF2 nanoparticles depending on pumping power and temperature have been discussed. The UC mechanism, especially the origin on the temperature-dependent UC emission intensities ratio between 2H11/2 and 4S3/2 levels, have been proposed.

Simultaneous phase- and morphology-controlled synthesis of MnO2 crystals through controlled release of cuprous ions in hydrothermal condition

2009 ◽  
Vol 24 (1) ◽  
pp. 58-65 ◽  
Author(s):  
Yange Zhang ◽  
Zhi Zheng ◽  
Ka Wai Wong ◽  
Fengling Yang ◽  
Zude Zhang
Keyword(s):  
Electron Microscopy ◽  
Hydrothermal Condition ◽  
Redox System ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
Experimental Conditions ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Electron ◽  
Cuprous Ions

The α-, β-, and δ-MnO2 with various morphologies have been synthesized by a novel redox system of KMnO4 and CuCl with HCl added under a hydrothermal condition. The resultant MnO2 products have been characterized by x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Upon control of reaction temperature and duration, it was observed that MnO2 polymorphs of different morphology (e.g., flowery δ-MnO2, β-MnO2 nanowires and octahedrons, α-MnO2 nanowires) can be prepared in an adjustable manner. The phenomenon is mainly attributed to the effect of cuprous ions controllably released from CuCl by the action of HCl at different experimental conditions. The corresponding formation mechanism for the MnO2 crystals will also be proposed and discussed.

scholarly journals Oxalic Acid-Assisted Hydrothermal Synthesis and Luminescent of Hexagonal NaYF4:Ln3+ (Ln = Sm, Eu, Yb/Er) Micro/Nanoplates

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Feng Tao ◽  
Zhishun Shen ◽  
Zhijun Wang ◽  
Da Shu ◽  
Qi Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Oxalic Acid ◽  
Molar Ratio ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Display Systems

Hexagonal NaYF4:Ln3+ micro/nanoplates were successfully synthesized via a hydrothermal method using oxalic acid as a shape modifier. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED) have been used to study the morphologies and crystal structure of the products. The effects of the pH values and the molar ratio of oxalic acid to NaOH on the crystal growth have been investigated in detail. The time-dependent experiments have been conducted to investigate the morphology evolution process, and based on the results, a possible growth mechanism was proposed. The photoluminescence properties of 5 mol% Eu3+ and 3 mol% Sm3+ doped NaYF4 and 20 mol% Yb3+/2 mol% Er3+ codoped NaYF4 micro/nanoplates were investigated. The experimental results showed that NaYF4:Ln3+ micro/nanoplates have excellent luminescence and can be potential application in the field of light display systems, lasers, and optoelectronic devices.

Synthesis and Luminescence Properties of Yb3+/Ho3+ Co-Doped Lu2O3 Nanocrystalline Powders

2007 ◽  
Vol 280-283 ◽  
pp. 521-524
Author(s):  
Li Qiong An ◽  
Jian Zhang ◽  
Min Liu ◽  
Sheng Wu Wang
Keyword(s):  
Electron Microscopy ◽  
Upconversion Luminescence ◽  
Nanocrystalline Powders ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
Excitation Spectra ◽  
X Ray ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Co Doped

Yb3+ and Ho3+ co-doped Lu2O3 nanocrystalline powders were synthesized by a reversestrike co-precipitation method. The as-prepared powders were examined by the X-ray diffraction and transmission electron microscopy. The phase composition of the powders was cubic and the particle size was in the range of 30~50 nm. Emission and excitation spectra of the powders were measured by a spectrofluorometer and the possible upconversion luminescence mechanism was also discussed.

Controlled Synthesis of Homogeneous Carbon Nano-Capsules Based on Biomaterials

2008 ◽  
Vol 58 ◽  
pp. 27-31 ◽  
Author(s):  
Yu Liang An ◽  
Yan Qiu Liu ◽  
Xia Yuan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Carbon Nanomaterials ◽  
Controlled Synthesis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrogen Flow ◽  
Fe Catalyst ◽  
Transmission Electron ◽  
Carbon Nanocapsules

A novel and practical route for preparing carbon nanocapsules using biomass – starch as the starting materials was presented. Carbon nanocapsules can be effectively synthesized by catalytic carbonizing starch in hydrogen flow. The carbohydrate was carbonized in a controllable way that leads to a large amount of carbon cages nanoparticles under Fe catalyst. Transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) were employed to characterizing carbon nanomaterials. The growth mechanism of carbon nanocapsules is briefly discussed in term of composition of precursor.

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