scholarly journals Structural and Spectroscopic Characterization of PM 597 Dye-Silica Core-Shell Nanoparticles

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Tahani R. Al-Biladi ◽  
A. S. Al Dwayyan ◽  
M. Naziruddin Khan ◽  
Saif M. H. Qaid ◽  
Khalid Al Zahrani
Keyword(s):  
Emission Spectra ◽  
Spectroscopic Characterization ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Silica Core ◽  
Shell Particles ◽  
Average Size ◽  
Core Shell Nanoparticles ◽  
20 Nm

Nanostructured fluorescent pyrromethene (PM) doped-silica core-shell particles were successfully prepared by Stöber process. The average size of the particles was in the range of 10–20 nm measured by TEM micrograph. The atomic structure and morphology of PM 597/SiO2core/shell nanoparticles were studied by AFM and SEM, respectively. Absorption and emission spectra of the PM 597/SiO2core/shell nanoparticles under the UV irradiation were studied and not significantly influenced at the position of peaks. Finally, amplified spontaneous emission (ASE) and photobleaching of dye were examined and found no significant influence on the peaks of PM dye due to the formation of smaller sizes of PM 597/SiO2core/shell nanoparticles. The observed PM 597/SiO2core/shell nanoparticles were different in shapes with smaller size distribution and highly luminescent. Majority of nanoparticles were roughly spherical with many of them aggregated. The less photobleaching of dye core may be due to the protection of pumped energy by SiO2shell and restricts the leakage of dye.

Formation of Core-Shell Nanoparticles by Laser Ablation of Copper and Brass in Liquids

2005 ◽  
Vol 106 ◽  
pp. 23-26 ◽  
Author(s):  
P.V. Kazakevich ◽  
A.V. Simakin ◽  
V.V. Voronov ◽  
G.A. Shafeev ◽  
D. Starikov ◽  
...  
Keyword(s):  
Core Shell ◽  
Copper Vapour Laser ◽  
Shell Nanoparticles ◽  
Liquid Environment ◽  
Pulsed Nd:Yag Laser ◽  
Plasmon Peak ◽  
Average Size ◽  
Core Shell Nanoparticles ◽  
20 Nm ◽  
Surrounding Liquid

Experimental results are presented on the ablation of copper and brass targets in a liquid environment: ethanol, acetone, or water by irradiation with either a pulsed copper vapour laser (0.51 μm) or a pulsed Nd:YAG laser (1.06 μm). The ablated material was ejected into the surrounding liquid as nanoparticles of average size 20 nm. The nanoparticle composition depends on the nature of the liquid. Ablation of 60%Cu, 40%Zn brass in ethanol results in formation of core-shell nanoparticles. Brass nanoparticles were characterized by a well-defined plasmon peak at 510-520 nm.

scholarly journals Preparation and Characterization of Magnetite – Silica Core – Shell Nanoparticles

2021 ◽  
Vol 15 ◽  
pp. 1457-1463
Author(s):  
S. N. Vakhneev ◽  
Minggong Sha
Keyword(s):  
Magnetite Nanoparticles ◽  
Biomedical Applications ◽  
Core Shell ◽  
Amino Groups ◽  
Absorption Bands ◽  
Shell Nanoparticles ◽  
Oh Groups ◽  
Silica Core ◽  
Core Shell Nanoparticles

In this study, two types of ligands were introduced onto the surface of magnetite nanoparticles by hydrolysis and condensation of organosilicon reagents: organosilane-tetraethoxysilane (TEOS) and aminoorganosilane - aminopropyltriethoxysilane (APTES). It is shown that coatings based on SiO2 solve a double problem: first, they prevent the aggregation of nanoparticles and the oxidation of magnetite; secondly, they allow the surface to be modified with various specific ligands for biomedical applications due to terminal groups. It was shown, that after the modification of TEOS and APTES (in argon and in air), the Fe3O4 content decreases to 66, 42, and 36%, respectively. The formation of a silicon framework on the magnetite surface due to Fe-O-Si and Si-O-Si bonds was determined by IR spectroscopy. The identification of surface amino groups is complicated due to the superposition of absorption bands of NH2- and OH-groups. This opens new prospective for creation of tailored nanocomposites containing magnetite nanoparticles. These materials can be further used as sorbents for various applications.

scholarly journals Synthesis and characterization of mesoporous silica core-shell particles

2010 ◽  
Vol 4 (2) ◽  
pp. 81-85 ◽  
Author(s):  
Milan Nikolic ◽  
Konstantinos Giannakopoulos ◽  
Vladimir Srdic
Keyword(s):  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Silica Particles ◽  
Core Shell ◽  
Functionalized Silica ◽  
Silica Core ◽  
Shell Particles ◽  
Average Size ◽  
Core Particles

Core-shell particles were formed by deposition of primary silica particles synthesized from sodium silicate solution on functionalized silica core particles (having size of ~0.5 ?m) prepared by hydrolysis and condensation of tetraethylortosilicate. The obtained mesoporous shell has thickness of about 60 nm and consists of primary silica particles with average size of ~21 nm. Scanning electron microscopy and zeta potential measurements showed that continuous silica shell exists around functionalized core particles which was additionally proved by FTIR and TEM results.

Synthesis and Characterization of Silylated Kaolinite/Silica Core–Shell Nanoparticles

2011 ◽  
Vol 105-107 ◽  
pp. 1760-1763
Author(s):  
Qian Zhang ◽  
Bai Mei Zhang
Keyword(s):  
Sol Gel ◽  
Core Shell ◽  
Silane Treatment ◽  
Shell Nanoparticles ◽  
Ultrafine Silica ◽  
Gel Technique ◽  
Silica Core ◽  
Kaolinite Surface ◽  
Core Shell Nanoparticles

Studies were conducted on the production of silane modified kaolinite/silica core-shell nanoparticles (SMKS). The SMKS nanoparticles were prepared via the sol–gel technique using tetraethyl oxysilane (TEOS) as the precursor to form silica shells on the surface of kaolinite particles followed with silane treatment. TEM of the unmodified kaolin (ORK) and SMKS revealed that a layer of ultrafine silica particles were deposited on the kaolinite surface to form a new kind of core–shell structure particles.

Preparation, Characterization, and Surface-Enhanced Raman Spectroscopy Activity of Spherical α-Fe2O3/Ag Core/Shell Nanoparticles

2010 ◽  
Vol 152-153 ◽  
pp. 67-72 ◽  
Author(s):  
Chun Rong Wang ◽  
Zhu Fa Zhou ◽  
Yan Jie Li ◽  
Ran Ran Tian ◽  
Xiao Chun Dai
Keyword(s):  
Ag Nanoparticles ◽  
Surface Enhanced Raman Spectroscopy ◽  
Reduction Reaction ◽  
Core Shell ◽  
Shell Nanoparticles ◽  
Surface Enhanced ◽  
Surface Enhanced Raman ◽  
Shell Particles ◽  
Average Size ◽  
Core Shell Nanoparticles

Spherical α-Fe2O3/Ag core/shell nanoparticles were prepared by reducing Ag(NH3)2+ with formaldehyde using the seeding method. 3- Aminopropyltriethoxysilane (APS) acts as a “bridge” to link between α-Fe2O3 core and Ag shell. The obtained nanoparticles were characterized by XRD, TEM, SEM, EDS, and Roman. The results show thatα-Fe2O3 cores are coated by Ag shell completely. The average size of α-Fe2O3/Ag nanoparticles is 95 nm and the thicknesses of Ag shell are 15nm in 3.7% HCHO and 1.0M AgNO3. The thickness of Ag shell can be tunable by changing reaction conditions, such as the concentration of AgNO3, reduction reaction rate. The surface-enhanced Raman scattering (SERS) effect of the core/shell particles are measured with Pyridine (Py) as molecule probe. SERS indicate that the Raman signals of Py adsorbed on α-Fe2O3/Ag nanoparticles exhibit large enhancement at 1010 and 1038 cm-1 respectively. And the intensity of signals is enhanced with the increase of the thickness of Ag shell. The uniform and rough surface of α-Fe2O3/Ag particles exhibits strong SERS activity in 3.7% HCHO and 1.0M AgNO3. The spherical α-Fe2O3/Ag core/shell nanoparticles exhibit SERS activity.

Sign in / Sign up

Export Citation Format

Share Document