The improvement of the amorphous environment of the germanate–tellurate glasses in the presence of the gadolinium ions

The improvement of the amorphous environment of the germanate–tellurate glasses in the presence of the gadolinium ions: "

Abstract

Glasses in the system xGd₂O₃·(100 − x)[TeO₂·GeO₂] with 0 ≤ x ≤ 50 mol% have been prepared from melt quenching method. In this paper, we investigated changes of the coordination numbers
of germanium, tellurium, and gadolinium ions by investigations of FTIR, EPR, and UV–VIS spectroscopy. By analyzing the structural
changes resulted from the IR spectra we found that the bending modes of [GeO₄] structural units and the deformed modes of the Te–O–Te linkages produce intercalation of the [GdO
_n
] entities in the germanate–tellurate chain network and densification of the glasses by increasing the number of [GeO₆] structural units. EPR spectra of the studied samples reveal that the gadolinium ions play a role of network former. The
UV–VIS spectra show broad UV absorption bands located in the 250–350 nm region. Their intensity increase with the increasing
of Gd₂O₃ content showing that these stronger transitions can be due to the presence of the O=Ge bonds (n–π* excitations) of [GeO₅] structural units. The [GeO₅] structural units are more stable thermodynamically than their analogues and the [GeO₆] structural units produce the improvement of the amorphous character of these glasses.

• Content Type Journal Article
• DOI 10.1007/s10853-010-4913-6
• Authors
  
  • S. Rada, Department of Physics, Technical University of Cluj-Napoca, 400641 Cluj-Napoca, Romania
  • R. Chelcea, Department of Physics, Technical University of Cluj-Napoca, 400641 Cluj-Napoca, Romania
  • M. Culea, Faculty of Physics, Babes-Bolyai University, 400084 Cluj-Napoca, Romania
  • E. Culea, Department of Physics, Technical University of Cluj-Napoca, 400641 Cluj-Napoca, Romania

• Journal Journal of Materials Science
• Online ISSN 1573-4803
• Print ISSN 0022-2461

"

Synthesis and optical studies of GdCrO3 nanoparticles

Synthesis and optical studies of GdCrO3 nanoparticles: "

Abstract

Here we report for the first time, a detailed synthesis mechanism of GdCrO₃ nanoparticles using a surfactant-less hydrothermal method. We also report a detailed study of their structural and optical
properties. The selected area electron diffraction and powder X-ray diffraction studies of GdCrO₃ nanoparticles show pure phase and excellent crystallinity with average particle size around 50–60 nm. The structural analysis
indicates a distorted perovskite crystal structure with lattice parameter values of a = 5.3099 ± 0.0022, b = 5.51793 ± 0.00226, and c = 7.60426 ± 0.00315 Å. For the first time, we report the room temperature UV–vis, photoluminescence, FTIR, and X-ray photoelectron
spectroscopy results and their detailed analysis for GdCrO₃. These results provide optical signatures of the formation of GdCrO₃ where both Gd³⁺ and Cr³⁺ play dominant role in different frequency regions.

• Content Type Journal Article
• DOI 10.1007/s11051-010-0090-4
• Authors
  
  • Adhish Jaiswal, Physical and Materials Chemistry Division, National Chemical Laboratory, Pune, 411 008 India
  • Raja Das, Physical and Materials Chemistry Division, National Chemical Laboratory, Pune, 411 008 India
  • Suguna Adyanthaya, Physical and Materials Chemistry Division, National Chemical Laboratory, Pune, 411 008 India
  • Pankaj Poddar, Physical and Materials Chemistry Division, National Chemical Laboratory, Pune, 411 008 India

• Journal Journal of Nanoparticle Research
• Online ISSN 1572-896X
• Print ISSN 1388-0764

"

Surface Photoluminescence Emission of ZnO Nanorod Arrays: Experimental and First-Principles Investigation

Surface Photoluminescence Emission of ZnO Nanorod Arrays: Experimental and First-Principles Investigation: "

The Journal of Physical Chemistry C

DOI: 10.1021/jp106646e

"

Physical and Chemical Analyses on Single-Source Precursor-Grown CdS Semiconductor Nanomaterials

Physical and Chemical Analyses on Single-Source Precursor-Grown CdS Semiconductor Nanomaterials: "

The Journal of Physical Chemistry C

DOI: 10.1021/jp104233x

"

Silica−Polymer Dual Layer-Encapsulated Quantum Dots with Remarkable Stability

Silica−Polymer Dual Layer-Encapsulated Quantum Dots with Remarkable Stability: "

ACS Nano

DOI: 10.1021/nn1017044

"

Highly Efficient Precursors for Direct Synthesis of Tailored CdS Nanocrystals in Organic Polymers

Highly Efficient Precursors for Direct Synthesis of Tailored CdS Nanocrystals in Organic Polymers: "

The Journal of Physical Chemistry C

DOI: 10.1021/jp104097w

"

Highly Strained Compliant Optical Metamaterials with Large Frequency Tunability

Highly Strained Compliant Optical Metamaterials with Large Frequency Tunability: "

Nano Letters

DOI: 10.1021/nl102684x

"

Charge Transfer Enhancement in the SERS of a Single Molecule

Charge Transfer Enhancement in the SERS of a Single Molecule: "

Nano Letters

DOI: 10.1021/nl102026p

"

Gold decorated NaYF4:Yb,Er/NaYF4/silica (core/shell/shell) upconversion nanoparticles for photothermal destruction of BE(2)-C neuroblastoma cells

Gold decorated NaYF4:Yb,Er/NaYF4/silica (core/shell/shell) upconversion nanoparticles for photothermal destruction of BE(2)-C neuroblastoma cells: "

Abstract

Gold decorated NaYF₄:Yb,Er/NaYF₄/silica (core/shell/shell) upconversion (UC) nanoparticles (~70–80 nm) were synthesized using tetraethyl orthosilicate and
chloroauric acid in a one-step reverse microemulsion method. Gold nanoparticles (~6 nm) were deposited on the surface of silica
shell of these core/shell/shell nanoparticles. The total upconversion emission intensity (green, red, and blue) of the core/shell/shell
nanoparticles decreased by ~31% after Au was deposited on the surface of silica shell. The upconverted green light was coupled
with the surface plasmon of Au leading to rapid heat conversion. These UC/silica/Au nanoparticles were very efficient to destroy
BE(2)-C cancer cells and showed strong potential in photothermal therapy.

• Content Type Journal Article
• DOI 10.1007/s11051-010-0080-6
• Authors
  
  • Li Peng Qian, Department of Materials Science and Engineering, National University of Singapore, Kent Ridge, Singapore, 117540 Republic of Singapore
  • Li Han Zhou, Department of Biochemistry, National University of Singapore, Kent Ridge, Singapore, 119260 Republic of Singapore
  • Heng-Phon Too, Department of Biochemistry, National University of Singapore, Kent Ridge, Singapore, 119260 Republic of Singapore
  • Gan-Moog Chow, Department of Materials Science and Engineering, National University of Singapore, Kent Ridge, Singapore, 117540 Republic of Singapore

• Journal Journal of Nanoparticle Research
• Online ISSN 1572-896X
• Print ISSN 1388-0764

"

Fluorescent Chemosensor for Detection and Quantitation of Carbon Dioxide Gas

Fluorescent Chemosensor for Detection and Quantitation of Carbon Dioxide Gas: "

Journal of the American Chemical Society

DOI: 10.1021/ja103947j

"

Parameters effects on the surface morphology and structure of Nd:YAG nanopowders synthesized by co-precipitation method

Parameters effects on the surface morphology and structure of Nd:YAG nanopowders synthesized by co-precipitation method: "

Abstract

In recent years, many attempts are made to produce Nd:YAG rods from its nanopowders instead of single crystals because of
difficulties and complications of the crystal growth. The quality of new rods is strongly depended on the grain size and agglomeration
amount of primary nanopowders. Co-precipitation method is one of the applicable methods to produce Nd:YAG powders with nano
sizes; however, with usual co-precipitation method, the grains size are large and the agglomeration amount is high yet. This
method contains different steps and parameters that any change of them leads in grains morphological and structural variations.
This article’s purpose was to report the effect of different experimental parameters on controlling the quality of the Nd:YAG
nanopowders. Some chemical and physical variations on usual co-precipitation method were designed based on particle growth
process analysis and performed. By analyzing the result of performed experiments on the grains properties, a modified co-precipitation
method could be achieved. This modified method allows the synthesizing of pure YAG powders with smaller grain size and lower
agglomeration in comparison with usual co-precipitation technique. It is claimed that this modified method can be applied
for a large number of materials produced by the usual co-precipitation technique.

• Content Type Journal Article
• DOI 10.1007/s11051-010-0055-7
• Authors
  
  • S. Arabgari, Physics Department, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, P.O. Box 14115-175, Islamic Republic of Iran
  • R. Malekfar, Physics Department, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, P.O. Box 14115-175, Islamic Republic of Iran
  • K. Motamedi, Physics Department, Faculty of Basic Sciences, Tarbiat Modares University, Tehran, P.O. Box 14115-175, Islamic Republic of Iran

• Journal Journal of Nanoparticle Research
• Online ISSN 1572-896X
• Print ISSN 1388-0764

"

Luminescence properties of monodispersed spherical BaWO4:Eu3+ microphosphors for white light-emitting diodes

Luminescence properties of monodispersed spherical BaWO4:Eu3+ microphosphors for white light-emitting diodes: "

Abstract

Monodispersed spheres (1–4 μm in diameter) of BaWO₄:Eu³⁺ (hereafter BWO:Eu) red-phosphor exhibiting intense emission at 615 nm were synthesized via a mild hydrothermal method. X-ray
diffraction, scanning electron microscope, photoluminescence excitation and emission spectra, and decay curve were used to
characterize the properties of BWO:Eu phosphors. An intense red emission was obtained by exciting either into the ⁵L₆ state with 394 nm or the ⁵D₂ state with 465 nm, that correspond to two popular emission lines from near-UV and blue LED chips, respectively. The values
of Ω
_2,4 experimental intensity parameters (13.8 × 10⁻²⁰ and 8.2 × 10⁻²⁰ cm²) are determined. The high-emission quantum efficiency of the BWO:Eu phosphor suggests this material could be promising red
phosphors for generating white light in phosphor-converted white light-emitting diodes.

• Content Type Journal Article
• DOI 10.1007/s10853-010-4891-8
• Authors
  
  • Jinsheng Liao, School of Material and Chemistry Engineering, Jiangxi University of Science and Technology, Ganzhou, Jiangxi, 341000 China
  • Bao Qiu, School of Material and Chemistry Engineering, Jiangxi University of Science and Technology, Ganzhou, Jiangxi, 341000 China
  • He-Rui Wen, School of Material and Chemistry Engineering, Jiangxi University of Science and Technology, Ganzhou, Jiangxi, 341000 China
  • Yong Li, School of Material and Chemistry Engineering, Jiangxi University of Science and Technology, Ganzhou, Jiangxi, 341000 China
  • Ruijin Hong, School of Material and Chemistry Engineering, Jiangxi University of Science and Technology, Ganzhou, Jiangxi, 341000 China
  • Hangying You, School of Material and Chemistry Engineering, Jiangxi University of Science and Technology, Ganzhou, Jiangxi, 341000 China

• Journal Journal of Materials Science
• Online ISSN 1573-4803
• Print ISSN 0022-2461

"

Ultrasensitive SERS Detection of TNT by Imprinting Molecular Recognition Using a New Type of Stable Substrate

Ultrasensitive SERS Detection of TNT by Imprinting Molecular Recognition Using a New Type of Stable Substrate: "

Abstract

We report herein a method for the ultra-trace detection of TNT on p-aminothiophenol-functionalized silver nanoparticles coated on silver molybdate nanowires based on surface-enhanced Raman scattering (SERS). The method relies on π-donor–acceptor interactions between the π-acceptor TNT and the π-donor p,p′-dimercaptoazobenzene (DMAB), with the latter serving to cross-link the silver nanoparticles deposited on the silver molybdate nanowires. This system presents optimal imprint molecule contours, with the DMAB forming imprint molecule sites that constitute SERS “hot spots”. Anchoring of the TNT analyte at these sites leads to a pronounced intensification of its Raman emission. We demonstrate that TNT concentrations as low as 10⁻¹² M can be accurately detected using the described SERS assay. Most impressively, acting as a new type of SERS substrate, the silver/silver molybdate nanowires complex can yield new silver nanoparticles during the detection process, which makes the Raman signals very stable. A detailed mechanism for the observed SERS intensity change is discussed. Our experiments show that TNT can be detected quickly and accurately with ultra-high sensitivity, selectivity, reusability, and stability. The results reported herein may not only lead to many applications in SERS techniques, but might also form the basis of a new concept for a molecular imprinting strategy.

SERS substrates: The ultra-trace detection of TNT based on surface-enhanced Raman scattering (SERS) is reported. The method relies on π-donor–acceptor interactions between the π-acceptor TNT and the π-donor p,p′-dimercaptoazobenzene (DMAB), with the latter serving to cross-link silver nanoparticles deposited on the surface of silver molybdate nanowires (see scheme).

"

Multistimuli Two-Color Luminescence Switching via Different Slip-Stacking of Highly Fluorescent Molecular Sheets

Multistimuli Two-Color Luminescence Switching via Different Slip-Stacking of Highly Fluorescent Molecular Sheets: "

Journal of the American Chemical Society

DOI: 10.1021/ja1044665

"

Optical Properties of Selenium Quantum Dots Produced with Laser Irradiation of Water Suspended Se Nanoparticles

Optical Properties of Selenium Quantum Dots Produced with Laser Irradiation of Water Suspended Se Nanoparticles: "

The Journal of Physical Chemistry C

DOI: 10.1021/jp105037w

"

Quantized Ostwald Ripening of Colloidal Nanoparticles

Quantized Ostwald Ripening of Colloidal Nanoparticles: "

The Journal of Physical Chemistry C

DOI: 10.1021/jp105071a

"

Template-Free and Direct Electrochemical Deposition of Hierarchical Dendritic Gold Microstructures: Growth and Their Multiple Applications

Template-Free and Direct Electrochemical Deposition of Hierarchical Dendritic Gold Microstructures: Growth and Their Multiple Applications: "

The Journal of Physical Chemistry C

DOI: 10.1021/jp105929b

"

Influence of Size, Shape, and Surface Coating on the Stability of Aqueous Suspensions of CdSe Nanoparticles

Influence of Size, Shape, and Surface Coating on the Stability of Aqueous Suspensions of CdSe Nanoparticles: "

Chemistry of Materials

DOI: 10.1021/cm101262s

"

SERS-Active Gold Lace Nanoshells with Built-in Hotspots

SERS-Active Gold Lace Nanoshells with Built-in Hotspots: "

Nano Letters

DOI: 10.1021/nl101946c

"

Luminescence and EPR studies of Y2O3:Gd3+ phosphors prepared via solution combustion method

Luminescence and EPR studies of Y2O3:Gd3+ phosphors prepared via solution combustion method: "

Abstract

Gadolinium-activated Y₂O₃ phosphor has been prepared by combustion process in a short time of 5 min. The phosphors are well characterized by X-ray
diffraction, scanning electron microscopy, and energy-dispersive analysis of X-ray. The as-prepared Y₂O₃:Gd powder shows that all the peaks are due to the Y₂O₃ cubic phase. Upon UV light excitation (276 nm), the phosphor exhibits a strong and sharp UV emission at 314 nm and is ascribed
to

6 \textP 7/ 2 ® 8 \textS 7/ 2

transition of Gd³⁺ ions. The EPR spectrum of Y₂O₃:Gd phosphor exhibits resonance signals with effective g values at g = 1.96, g = 2.88, and g = 6.08 and are attributed to Gd³⁺ ions located at sites with weak, intermediate, and strong cubic symmetry fields, respectively. It is observed that the population
of spin levels (N) and linewidth depends on temperature. The paramagnetic susceptibility (χ) is also evaluated as a function
of temperature and discussed.

• Content Type Journal Article
• DOI 10.1007/s10853-010-4869-6
• Authors
  
  • Vijay Singh, Mechanical Engineering Department, Chung-Ang University, Seoul, 156-756 Korea
  • R. P. S. Chakradhar, Glass Technology Laboratory, Central Glass and Ceramic Research Institute, CSIR, Kolkata, 700032 India
  • J. L. Rao, Department of Physics, Sri Venkateswara University, Tirupati, 517-502 India
  • Isabelle Ledoux-Rak, Laboratoire de Photonique Quantique et Moleculaire, Institut d’Alembert, Ecole Normale Superieure de Cachan, 61 av. du President Wilson, 94-235 Cachan, France
  • Ho-Young Kwak, Mechanical Engineering Department, Chung-Ang University, Seoul, 156-756 Korea

• Journal Journal of Materials Science
• Online ISSN 1573-4803
• Print ISSN 0022-2461

"

Silver Nanosphere SERS Probes for Sensitive Identification of Pathogens

Silver Nanosphere SERS Probes for Sensitive Identification of Pathogens: "

The Journal of Physical Chemistry C

DOI: 10.1021/jp1015406

"

Wet Chemical Synthesis of Monodisperse Colloidal Silver Nanocrystals Using Digestive Ripening

Wet Chemical Synthesis of Monodisperse Colloidal Silver Nanocrystals Using Digestive Ripening: "

The Journal of Physical Chemistry C

DOI: 10.1021/jp911316e

"

Gold nanostructures: a class of multifunctional materials for biomedical applications

Gold nanostructures: a class of multifunctional materials for biomedical applications: "


Claire M. Cobley, Jingyi Chen, Eun Chul Cho, Lihong V. Wang, Younan Xia

(Tutorial Review from Chem. Soc. Rev.)

Claire M. Cobley, Chem. Soc. Rev., 2011, DOI: 10.1039/b821763g

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