Sol–Gel Fabrication and Luminescence Properties of Multilayer Eu-Doped BaTiO3–SiO2 Xerogel Nanostructures

2019 ◽  
Vol 18 (03n04) ◽  
pp. 1940044 ◽  
Author(s):  
Yu. D. Karnilava ◽  
P. A. Kholov ◽  
N. V. Gaponenko ◽  
T. F. Raichenok ◽  
S. A. Tikhomirov ◽  
...  

With the use of sol–gel method BaTiO3–SiO2 multilayer structures were fabricated on glass or fused silica substrates employing dipping or spinning procedure. The photonic stop band was observed in the reflection and transmission spectra of the multilayer structure annealed at [Formula: see text]C. It is redshifted with an increase of the thicknesses of BaTiO3 and SiO2 layers. For structures comprising Eu-doped BaTiO3 layers of different thicknesses photoluminescence with the main band at 614[Formula: see text]nm was detected. It is characterized with the double-exponential decay with the lifetimes of about 0.5[Formula: see text]ms and 1.1[Formula: see text]ms which do not depend significantly on the photonic stop band position.

2020 ◽  
Vol 10 (03) ◽  
pp. 2050005
Author(s):  
N. Gaponenko ◽  
D. Parafinyuk ◽  
P. Kholov ◽  
T. Raichenok ◽  
S. Prislopski

Sol–gel technology was applied to fabricate Eu-doped BaTiO3/SiO2 multilayer structures by spinning on silicon and fused silica substrates. Eu photoluminescence (PL) was investigated depending on the annealing temperature of these structures. The samples demonstrate the room temperature luminescence corresponding to 5[Formula: see text]FJ ([Formula: see text], 2, 3, 4) transitions of trivalent europium with the most intensive band at 615 nm. For the structure on fused silica with Eu in the BaTiO3 cavity, increase of the annealing temperature from [Formula: see text]C to [Formula: see text]C results in modification of the luminescence indicatrix and lowering of the luminescence intensity in the direction along the surface normal. For BaTiO3/SiO2 multilayer structure generated on silicon, scanning electron microscopy (SEM) analyses reveal disordering after annealing at [Formula: see text]C. This heat treatment provides also an increase of the Eu luminescence intensity.


2011 ◽  
Vol 311-313 ◽  
pp. 1217-1221
Author(s):  
Zheng Wen Yang ◽  
Ji Zhou ◽  
Jian Bei Qiu ◽  
Zhi Guo Song ◽  
Da Cheng Zhou ◽  
...  

Inverse opal photonic crystals of Eu3+ doped LaPO4 (LaPO4: Eu)were prepared by a self-assembly technique in combination with a sol-gel method. In the preparation process, Eu3+ doped LaPO4 precursors were filled into the interstices of the opal template assembled by monodispersive polystyrene microspheres. The polystyrene template was then removed by calcination at 650 °C for 5h, meanwhile, Eu3+doped LaPO4 inverse opal photonic crystal was formed. The photoluminescence (PL) from Eu3+ doped LaPO4 inverse opal photonic crystal was studied. The effect of the photonic stop-band on the spontaneous emission of Eu3+ has been observed in the inverse opal photonic crystals of Eu3+ doped LaPO4. Significant suppression of the emission was detected if the photonic band-gap overlaps with the Eu3+ ions emission band.


2020 ◽  
Vol 92 (1) ◽  
pp. 10901
Author(s):  
Saloua El Asri ◽  
Hamid Ahamdane ◽  
Lahoucine Hajji ◽  
Mohamed El Hadri ◽  
Moulay Ahmed El Idrissi Raghni ◽  
...  

Forsterite single phase powder Mg2SiO4 was synthesized by sol–gel method alongside with heat treatment, using two different cation alkaline salts MCl as mineralizers (M = Na, K) with various mass percentages (2.5, 5, 7.5, and 10 wt.%). In this work, we report on the effect of the cation type and the added amount of used mineralizer on microstructure and electrical conductivity of Mg2SiO4. The formation of forsterite started at 680–740  °C and at 630–700  °C with KCl and NaCl respectively, as shown by TG-DTA and confirmed by XRD. Furthermore, the Fourier transform infrared (FTIR) transmission spectra indicated bands corresponding to vibrations of forsterite structure. The morphology and elemental composition of sintered ceramics were examined by SEM-EDX analyses, while their densities, which were measured by Archimedes method, increased with addition of both alkaline salts. The electrical measurements were performed by Complex Impedance Spectroscopy. The results showed that electrical conductivity increased with the addition of both mineralizers, which was higher for samples prepared with NaCl than those prepared with KCl.


Optik ◽  
2021 ◽  
pp. 167259
Author(s):  
Wenfeng Sun ◽  
Xia Xiang ◽  
Bo Li ◽  
Xiang Dong ◽  
Xiaolong Jiang ◽  
...  

1981 ◽  
Vol 64 (12) ◽  
pp. C-178-C-180 ◽  
Author(s):  
Binod Kumar ◽  
N. Fernelius ◽  
J. A. Detrio

2013 ◽  
Vol 538 ◽  
pp. 297-300 ◽  
Author(s):  
Chien Jang Wu ◽  
Ya Ju Lee ◽  
Tzu Chyang King ◽  
Wen Kai Kuo

A design of multichannel transmission filter at microwave is proposed. It is based on the use of the finite plasma photonic crystal operating at frequency below the plasma frequency. We consider a design structures of (AB)qA, where A is the dielectric material, B is the plasma layer, and q is the number of periods. It is found that the number of channels is equal to q-1. We show that the locations such multiple channels are in the pass band of the infinite plasma-dielectric photonic crystal. The idea of such design is thus to engineer the photonic pass band, which is fundamentally different from the usual design by engineering the photonic stop band like the multilayer Fabry-Perot transmission filter. The physical mechanism of multiple channels is also discussed.


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