Photostimulable Fluorescent Nanoparticles for Biological Imaging

2011 ◽  
Vol 1342 ◽  
Author(s):  
Andres Osvet ◽  
Moritz Milde ◽  
Sofia Dembski ◽  
Sabine Rupp ◽  
Carsten Gellermann ◽  
...  
Keyword(s):  
Sol Gel ◽  
Red Light ◽  
Luminescent Properties ◽  
Transition Metal Ions ◽  
Biological Imaging ◽  
Core Shell ◽  
Fluorescent Nanoparticles ◽  
Photostimulated Luminescence ◽  
Phosphor Layer ◽  
Preparation Conditions

ABSTRACTSpherical monodisperse core/shell-type nanoparticles, comprising an amorphous SiO2 core coated with a luminescent phosphor layer were synthesized by the modified Pechini processes. The sol-gel method allows covering the 50 – 500 nm core particles with different inorganic phosphor layers of about 10 nm thickness, doped with rare-earth or transition metal ions which determine the luminescent properties. Particles comprising a Zn2SiO4 shell, doped with Mn2+ ions, are not only fluorescent under UV irradiation (260 nm), but store the activation energy by trapping electrons/holes at lattice defects. This energy is released as phosphorescence in the time scale of seconds and minutes, or as photostimulated luminescence under the excitation of red light (650 nm). Traps related to these processes are different, and their concentration is affected by the preparation conditions of the particles.

Synthesis of Ba2SiO4:Eu2+ by a Hybrid Process and Its Luminescent Properties

2015 ◽  
Vol 15 (10) ◽  
pp. 8155-8160 ◽  
Author(s):  
Jung Hye Park ◽  
Wonsik Ahn ◽  
Young Jin Kim
Keyword(s):  
Colloidal Silica ◽  
Particle Distribution ◽  
Sol Gel ◽  
Green Emission ◽  
Luminescent Properties ◽  
Hybrid Process ◽  
Photoluminescence Spectra ◽  
Preparation Conditions ◽  
Gel Combustion ◽  
Silicon Sources

Ba2SiO4:Eu2+ powders were prepared using a sol–gel-combustion (hybrid) process with tetraethyl orthosilicate (TEOS) and colloidal silica (C-SiO2) as Si sources. The effects of the silicon sources and preparation conditions on phase formation and luminescent properties were investigated. The B2S:Eu2+ powders synthesized with TEOS were composed of the irregular particles, whereas C-SiO2 was more conducive to uniform particle distribution for the Ba2SiO4:Eu2+ powders, leading to the enhancement of the emission intensity. The photoluminescence spectra of the synthesized powders exhibited broad excitation bands spanning 250 to 450 nm, and strong green-emission bands, whose intensities and positions were heavily dependent on the concentration of Eu2+ and Sr2+ substituted for Ba2+ in Ba2SiO4.

Synthesis and Luminescent Properties of Monodisperse Spherical SiO2/Ca10(PO4)6(OH)2: Eu3+ Particles with Core-Shell Structure

2014 ◽  
Vol 1004-1005 ◽  
pp. 344-347
Author(s):  
Huan Wang
Keyword(s):  
Smooth Surface ◽  
Calcium Phosphates ◽  
Sol Gel ◽  
Spherical Shape ◽  
Luminescent Properties ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process ◽  
Shell Particles

The growing necessity of biomaterials has increased the interest in calcium phosphates, particularly hydroxyapatite. In this paper, monodisperse and spherical SiO2particles have been coated with Ca10(PO4)6(OH)2:Eu3+layers via a Pechini sol-gel process, resulting in core-chell ctructured SiO2/Ca10(PO4)6(OH)2:Eu3+samples. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), photoluminescence (PL) spectra were employed to characterize the SiO2/Ca10(PO4)6(OH)2:Eu3+core-shell particles. The resulted core-shell particles have perfect spherical shape with narrow size distribution, smooth surface and non-agglomeration.

Synthesis and Luminescent Properties of Red Phosphor BaY2O4: Eu3+ for White Light-Emitting Diodes

2013 ◽  
Vol 811 ◽  
pp. 181-185 ◽  
Author(s):  
Lan Tu Ya Wu
Keyword(s):  
Sol Gel ◽  
Red Light ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Electric Dipole Transition ◽  
Excitation Spectra ◽  
Excitation Peak ◽  
Red Phosphor ◽  
Light Emitting ◽  
White Light Emitting Diodes

The rare-earth Eu3+doped BaY2O4red phosphor synthesized by citric acid sol-gel method. The structure, morphology and composition of the red phosphor were characterized by X-ray diffraction, scanning electron microscopy and infrared spectroscopy. The results show that the distribution of the pure phase BaY2O4: Eu3+particles after annealing at 800 °C was irregular, small size of particle is 0.2 μm to 0.4 μm. The excitation spectra of synthesized phosphor at 610 nm monitoring were composed of a broadband and a series of sharp peaks, the strongest excitation peak at 466 nm, the secondly at 395nm. It was indicated that BaY2O4: Eu3+phosphor matching with the widespread applied the output wavelengths of UV LED and blue LED chips. The main emission spectra of samples under blue light excitation is Eu3+ions5D07F2electric dipole transition with a strong red light, so that the BaY2O: Eu3+phosphor may be a better candidate for red component for white LED.

SYNTHESIS, PHASE TRANSFER AND SURFACE MODIFICATION OF HYDROPHOBIC QUANTUM DOTS FOR BIOAPPLICATIONS

2013 ◽  
Vol 06 (03) ◽  
pp. 1330003 ◽  
Author(s):  
RUILI ZHANG ◽  
XIAO ZHANG ◽  
XIAOYU LI ◽  
PING YANG
Keyword(s):  
Quantum Dots ◽  
Surface Modification ◽  
Phase Transfer ◽  
Sol Gel ◽  
Water Phase ◽  
Core Shell ◽  
Anisotropic Growth ◽  
Preparation Conditions ◽  
Sol Gel Process ◽  
Preparation Phase

We review the preparation, phase transfer, surface modification and possible bioapplications of hydrophobic CdSe based quantum dots (QDs). CdSe cores with rod and spherical morphologies were prepared through adjusting preparation conditions. The photoluminescence (PL) of the QDs depended strongly on preparation conditions. The QDs were coated with semiconductor shells to improve their PL properties. Anisotropic growth occurred during shell coating. Core/shell QDs revealed tunable PL and high PL efficiencies up to 90%. The phase transfer of QDs from oil phase to water phase was carried out via polymer or a sol–gel process. The silanization of the QDs plays an important role for the sol–gel process. Because of a SiO2 coating, the surface modification of the QDs for bioapplications became easy. After transferring into water phase, the QDs still retained high PL efficiency. Because of their high PL, these biofunctional materials could provide a platform for various applications.

Fabrication and luminescent properties of core-shell InGaN/GaN multiple quantum wells on GaN nanopillars

2012 ◽  
Vol 100 (26) ◽  
pp. 261103 ◽  
Author(s):  
J.-R. Chang ◽  
S.-P. Chang ◽  
Y.-J. Li ◽  
Y.-J. Cheng ◽  
K.-P. Sou ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Luminescent Properties ◽  
Multiple Quantum Wells ◽  
Core Shell ◽  
Multiple Quantum

Characterization and luminescent properties of SiO2:ZnS:Mn2+ and ZnS:Mn2+ nanophosphors synthesized by a sol–gel method

2009 ◽  
Vol 404 (22) ◽  
pp. 4470-4475 ◽  
Author(s):  
M.M. Biggs ◽  
O.M. Ntwaeaborwa ◽  
J.J. Terblans ◽  
H.C. Swart
Keyword(s):  
Sol Gel ◽  
Luminescent Properties ◽  
Gel Method ◽  
Sol Gel Method

Luminescent Properties of Zn2SiO4:Eu3+,Dy3+ Phosphors via Sol-Gel Process

2012 ◽  
Vol 217-219 ◽  
pp. 733-736
Author(s):  
Xiu Mei Han ◽  
Shu Ai Hao ◽  
Ying Ling Wang ◽  
Gui Fang Sun ◽  
Xi Wei Qi
Keyword(s):  
Thermal Analysis ◽  
Ir Spectra ◽  
Sol Gel ◽  
Luminescent Properties ◽  
Photoluminescence Spectra ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process ◽  
Ft Ir

Zn2SiO4:Eu3+, Dy3+ phosphors have been prepared through the sol-gel process. X-ray diffraction (XRD), thermogravimetric and ddifferential thermal analysis (TG-DTA), FT-IR spectra and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicated that the phosphors crystallized completely at 1000oC. In Zn2SiO4:Eu3+,Dy3+ phosphors, the Eu3+ and Dy3+ show their characteristic red(613nm, 5D0-7F2), blue (481nm, 4F9/2–6H15/2) and yellow (577nm, 4F9/2–6H13/2) emissions.

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