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

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.

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

Journal of Materials Research ◽

10.1557/jmr.2010.0255 ◽

2010 ◽

Vol 25 (10) ◽

pp. 2035-2041 ◽

Cited By ~ 18

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.

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Hydrothermal Synthesis and Tunable Multicolor Upconversion Emission of Cubic Phase Y2O3Nanoparticles

Advances in Condensed Matter Physics ◽

10.1155/2013/347406 ◽

2013 ◽

Vol 2013 ◽

pp. 1-6 ◽

Cited By ~ 2

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.

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Synthesis of Trilaminar Core–Shell Au/α-Fe2O3@SnO2Nanocomposites and their Application for Nonenzymatic Dopamine Electrochemical Sensing

NANO ◽

10.1142/s1793292019501388 ◽

2019 ◽

Vol 14 (11) ◽

pp. 1950138 ◽

Cited By ~ 1

Author(s):

Sai Zhang ◽

Shijun Yue ◽

Jiajia Li ◽

Jianbin Zheng ◽

Guojie Gao

Keyword(s):

Electron Microscopy ◽

High Sensitivity ◽

Electrochemical Sensing ◽

Synthesis Process ◽

Core Shell ◽

X Ray Diffraction ◽

X Ray ◽

Long Term Stability ◽

Transmission Electron

Au nanoparticles anchored on core–shell [Formula: see text]-Fe2O3@SnO2 nanospindles were successfully constructed through hydrothermal synthesis process and used for fabricating a novel nonenzymatic dopamine (DA) sensor. The structure and morphology of the Au/[Formula: see text]-Fe2O3@SnO2 trilaminar nanohybrid film were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The electrochemical properties of the sensor were investigated by cyclic voltammetry and amperometry. The experimental results suggest that the composites have excellent catalytic property toward DA with a wide linear range from 0.5[Formula: see text][Formula: see text]M to 0.47[Formula: see text]mM, a low detection limit of 0.17[Formula: see text][Formula: see text]M (S/[Formula: see text]) and high sensitivity of 397.1[Formula: see text][Formula: see text]A[Formula: see text]mM[Formula: see text][Formula: see text]cm[Formula: see text]. In addition, the sensor exhibits long-term stability, good reproducibility and anti-interference.

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Enhanced Red Upconversion Luminescence in Yb–Er Codoped NaYF4 Nanocrystals

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2016.11866 ◽

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.

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Crystalline phase transformation of colloidal cadmium sulfide nanocrystals

International Journal of Modern Physics B ◽

10.1142/s0217979217500370 ◽

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.

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

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2016.11804 ◽

2016 ◽

Vol 16 (4) ◽

pp. 3744-3748 ◽

Cited By ~ 2

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.

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Perspectives and limitations of symmetric X-ray Bragg reflections for inspecting polytypism in nanowires

Journal of Synchrotron Radiation ◽

10.1107/s1600577516000333 ◽

2016 ◽

Vol 23 (2) ◽

pp. 487-500 ◽

Cited By ~ 4

Author(s):

Martin Köhl ◽

Philipp Schroth ◽

Tilo Baumbach

Keyword(s):

Statistical Significance ◽

Large Set ◽

X Ray Diffraction ◽

Free Standing ◽

Time Resolved ◽

X Ray ◽

Transmission Electron ◽

Gaas Nanowires ◽

High Statistical Significance ◽

Proper Interpretation

X-ray diffraction, possibly time-resolved during growth or annealing, is an important technique for the investigation of polytypism in free-standing nanowires. A major advantage of the X-ray diffraction approach for adequately chosen beam conditions is its high statistical significance in comparison with transmission electron microscopy. In this manuscript the interpretation of such X-ray intensity distribution is discussed, and is shown to be non-trivial and non-unique given measurements of the [111]cor [333]creflection of polytypic nanowires grown in the (111)cdirection. In particular, the diffracted intensity distributions for several statistical distributions of the polytypes inside the nanowires are simulated and compared. As an example, polytypic GaAs nanowires are employed, grown on a Si-(111) substrate with an interplanar spacing of the Ga (or As) planes in the wurtzite arrangement that is 0.7% larger than in the zinc blende arrangement along the (111)cdirection. Most importantly, ambiguities of high experimental relevance in the case of strongly fluctuating length of the defect-free polytype segments in the nanowires are demonstrated. As a consequence of these ambiguities, a large set of deviations from the widely used Markov model for the stacking sequences of the nanowires cannot be detected in the X-ray diffraction data. Thus, the results here are of high relevance for the proper interpretation of such data.

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Solvothermal Synthesis of CeO2 Nanoparticles

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.236-238.2000 ◽

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).

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LASER-INDUCED PHOTOLUMINESCENT STUDIES OF Al-DOPED ZINC OXIDE NANOPARTICLES

International Journal of Nanoscience ◽

10.1142/s0219581x10007101 ◽

2010 ◽

Vol 09 (05) ◽

pp. 439-445

Author(s):

DHIRAJ KUMAR ◽

SUNIL KUMAR ◽

H. S. BHATTI

Keyword(s):

Zinc Oxide ◽

Zinc Oxide Nanoparticles ◽

Oxide Nanoparticles ◽

Nitrogen Laser ◽

X Ray Diffraction ◽

Electron Microscopic ◽

Time Resolved ◽

X Ray ◽

Aluminum Ions ◽

Transmission Electron

In this paper, addition of aluminum in zinc oxide is incorporated using low-temperature chemical synthesis route. Aluminum ions help in crystallization of zinc oxide nanoparticles. Characterization of the synthesized nanoparticles of zinc oxide has been done using Transmission electron microscope (TEM), and X-ray diffraction (XRD) analysis, Energy-resolved photoluminescence (PL) spectra and Time-resolved laser-induced photoluminescence (TRPL) at room temperature. Transmission electron microscopic observations and X-Ray diffraction studies indicate highly crystalline nature and particle size of the order of 20 nm in ZnO:Al . Time-resolved laser-induced photoluminescence measurements have been done using pulsed nitrogen laser as an excitation source, operated at wavelength 337.1 nm and having high peak output power of 1 MW. The results show that at higher concentrations of Al doping in host ZnO phosphor, emission intensity is more by several orders of magnitude and lifetime shortening indicates that these nanoparticles are more efficient as compared with lower concentrations of dopant.

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