scholarly journals Hydrothermal Synthesis and Tunable Multicolor Upconversion Emission of Cubic Phase Y2O3Nanoparticles

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Haibo Wang ◽  
Chao Qian ◽  
Zhigao Yi ◽  
Ling Rao ◽  
Hongrong Liu ◽  
...  
Keyword(s):  
Upconversion Luminescence ◽  
Upconversion Emission ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Light Yellow ◽  
Color Displays ◽  
Transmission Electron ◽  
Subsequent Calcination ◽  
Upconversion Emissions

Highly crystalline body-centered cubic structure Y2O3with lanthanide (Ln) codopants (Ln = Yb3+/Er3+and Yb3+/Ho3+) has been synthesized via a moderate hydrothermal method in combination with a subsequent calcination. The structure and morphology of Y(OH)3precursors and Y2O3nanoparticles were characterized by X-ray diffraction and transmission electron microscopy. The results reveal that the Y2O3nanoparticles possess cubic phase and form the quasispherical structure. The upconversion luminescence properties of Y2O3nanoparticles doped with different Ln3+(Yb3+/ Er3+and Yb3+/ Ho3+) ions were well investigated under the 980 nm excitation. The results show that the Yb3+/Er3+and Yb3+/Ho3+codoped Y2O3nanoparticles exhibit strong red and light yellow upconversion emissions, respectively. It is expected that these Y2O3nanoparticles with tunable multicolor output and intense red upconversion emission may have potential application in color displays and biolabels.

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.

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.

scholarly journals Enhancement of Visible Upconversion Emission in Y2O3:Er3+-Yb3+by Addition of Thiourea and LiOH in the Phosphor Synthesis

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Eder Resendiz-L ◽  
Luis Armando Diaz-Torres ◽  
Luis Octavio Meza Espinoza ◽  
Claramaria Rodríguez-González ◽  
Pedro Salas
Keyword(s):  
Electron Microscopy ◽  
Upconversion Luminescence ◽  
Xrd Analysis ◽  
Upconversion Emission ◽  
Synthesis Process ◽  
Cubic Phase ◽  
Photoluminescence Properties ◽  
X Ray Diffraction ◽  
Facile Hydrothermal Method ◽  
X Ray

Spherical like Y2O3nanostructures doped with Er3+and Yb3+ions have been synthesized by a facile hydrothermal method. The samples were prepared by using different precipitant agents in the synthesis process. The phosphors were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence spectroscopy. Effects of the precipitant agents on structural, morphological, and photoluminescence properties of Y2O3:Er3+-Yb3+are studied and discussed. XRD analysis indicates that all samples, prepared with different precipitant agents, present the same cubic phase. Electron microscopy measurements show regular spherical shapes with size diameter depending on precipitant agent. Photoluminescence reveals that the samples have strong green (563 nm) and red (660 nm) emissions corresponding to4S3/2 → 4I15/2and4F9/2 → 4I15/2transitions of Er3+ions, respectively. The nanophosphors prepared with both Thiourea and Lithium Hydroxide exhibit the stronger visible upconversion luminescence under 980 nm diode laser excitation.

scholarly journals Influence of Gd3+ doping concentration on the properties of Na(Y,Gd)F4:Yb3+, Tm3+ upconverting nanoparticles and their long-term aging behavior

2022 ◽  
Author(s):  
Anna López de Guereñu ◽  
Dennis T. Klier ◽  
Toni Haubitz ◽  
Michael U. Kumke
Keyword(s):  
Incubation Period ◽  
Upconversion Luminescence ◽  
Hexagonal Lattice ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Time Resolved ◽  
X Ray ◽  
Transmission Electron ◽  
Decay Times

AbstractWe present a systematic study on the properties of Na(Y,Gd)F4-based upconverting nanoparticles (UCNP) doped with 18% Yb3+, 2% Tm3+, and the influence of Gd3+ (10–50 mol% Gd3+). UCNP were synthesized via the solvothermal method and had a range of diameters within 13 and 50 nm. Structural and photophysical changes were monitored for the UCNP samples after a 24-month incubation period in dry phase and further redispersion. Structural characterization was performed by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) as well as dynamic light scattering (DLS), and the upconversion luminescence (UCL) studies were executed at various temperatures (from 4 to 295 K) using time-resolved and steady-state spectroscopy. An increase in the hexagonal lattice phase with the increase of Gd3+ content was found, although the cubic phase was prevalent in most samples. The Tm3+-luminescence intensity as well as the Tm3+-luminescence decay times peaked at the Gd3+ concentration of 30 mol%. Although the general upconverting luminescence properties of the nanoparticles were preserved, the 24-month incubation period lead to irreversible agglomeration of the UCNP and changes in luminescence band ratios and lifetimes.

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.

Crystalline phase transformation of colloidal cadmium sulfide nanocrystals

2017 ◽  
Vol 31 (06) ◽  
pp. 1750037
Author(s):  
M. Ghali ◽  
A. M. Eissa ◽  
M. M. Mosaad
Keyword(s):  
Phase Transformation ◽  
Optical Absorption ◽  
Crystalline Phase ◽  
Growth Conditions ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
X Ray ◽  
Ph Values ◽  
Transmission Electron

In this paper, we give a microscopic view concerning influence of the growth conditions on the physical properties of nanocrystals (NCs) thin films made of CdS, prepared using chemical bath deposition CBD technique. We show a crystalline phase transformation of CdS NCs from hexagonal wurtzite (W) structure to cubic zincblende (ZB) when the growth conditions change, particularly the solution pH values. This effect was confirmed using X-ray diffraction (XRD), transmission electron microscopy (TEM), optical absorption and photoluminescence (PL) measurements. The optical absorption spectra allow calculation of the bandgap value, [Formula: see text], where significant increase [Formula: see text]200 meV in the CdS bandgap when transforming from Hexagonal to Cubic phase was found.

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.

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.

Solvothermal Synthesis of CeO2 Nanoparticles

2011 ◽  
Vol 236-238 ◽  
pp. 2000-2003
Author(s):  
Yong Cai Zhang ◽  
En Ren Zhang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Absorption Spectrum ◽  
Photoelectron Spectroscopy ◽  
Solvothermal Synthesis ◽  
Oxygen Vacancies ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron

Ultrafine CeO2 nanoparticles were synthesized directly via solvothermal treatment of Ce(NO3)3·6H2O powder in toluene at 180 °C for 48 h, and characterized by X-ray diffraction (XRD), Raman, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and UV-vis absorption spectrum. The results from XRD, Raman and XPS revealed the formation of pure cubic phase CeO2 with some oxygen vacancies. The TEM image disclosed that the as-synthesized CeO2 comprised nanoparticles of about 5–8 nm. The UV-vis absorption spectrum showed that the as-synthesized CeO2 nanoparticles had a wide UV absorption band centered at around 326 nm (3.8 eV).

Blue Upconversion Luminescence Properties of La2(WO4)3:Yb3+/Tm3+Phosphor

2011 ◽  
Vol 399-401 ◽  
pp. 1020-1025
Author(s):  
Jin Sheng Liao ◽  
Hang Ying You ◽  
Qing Xia Wu ◽  
He Rui Wen ◽  
Jing Lin Chen ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Upconversion Luminescence ◽  
Hydrothermal Process ◽  
Pumping Power ◽  
X Ray Diffraction ◽  
X Ray ◽  
Laser Pumping ◽  
Upconversion Mechanism ◽  
Upconversion Emissions ◽  
Scanning Electron

Monoclinic La2(WO4)3 nanophosphors codoped with Tm3+ and Yb3+ ions were synthesized via hydrothermal process followed by heat treatment. Powder X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to characterize as-prepared samples. The dependences of Yb3+/ concentration and laser pumping power on the upconversion emissions were extensively investigated. The results show that upconversion luminescence increases with the Yb3+/ concentration and gets its peak at 30 %. The upconversion mechanism and process in the Yb3+/Tm3+ codoped La2(WO4)3 phosphors were analysed.

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