New Transparent Substrate with Silica Aerogel Film for Surface-Emissive Devices

2000 ◽  
Vol 660 ◽  
Author(s):  
H. Yokogawa ◽  
K. Kawano ◽  
M. Yokoyama ◽  
T. Tsutsui ◽  
M. Yahiro ◽  
...  
Keyword(s):  
Refractive Index ◽  
Glass Substrate ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Transparent Electrode ◽  
Light Sources ◽  
Photoluminescence Intensity ◽  
Transparent Substrate ◽  
Low Refractive Index

ABSTRACTSilica aerogels prepared by sol-gel methods with supercritical drying process have transparency and extremely low refractive index which is not available in any other materials. This extraordinary refractivity is expected to present some new features as an optical material. Ordinarily, coupling-out efficiency of surface-emissive light sources has been assumed to be low. It is due to the losses organized from internal reflection of emitted light at the air-glass interface and dissipation during wave-guiding propagation within the substrate.However, when material that has extremely low refractive index is inserted between a thin luminescence layer and glass substrate, almost all the light from the luminescence layer can efficiently couple out to air passing through the glass substrate. In this report, we introduce a silica aerogel film as a low refractive index material for surface-emissive devices, such as photoluminescent and electroluminescent device. In the experiments, the photoluminescence intensity of Alq3 through the silica aerogel layer was twice as large as that of the glass substrate without the silica aerogel film. Moreover, we formed a new substrate which contained a transparent electrode on the silica aerogel film. Using this substrate, we fabricated the OLED and observed the disappearance of wave-guiding propagation within the glass substrate.

Hydrophobic, ultra-low refractive index films prepared by sol-gel process

2016 ◽  
Vol 184 ◽  
pp. 305-307 ◽  
Author(s):  
Ye Yuan ◽  
Genghua Yan ◽  
Shaozhe Liu ◽  
Xiaodi Lu ◽  
Ruijiang Hong
Keyword(s):  
Refractive Index ◽  
Sol Gel ◽  
Sol Gel Process ◽  
Low Refractive Index

Epitaxial Growth And Optical Properties of Sol-Gel (Pb,La)Ti03 Thin Films for Waveguides

1997 ◽  
Vol 474 ◽  
Author(s):  
Junmo Koo ◽  
Changho Lee ◽  
Kwangsoo No ◽  
Byeong-Soo Bae
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Refractive Index ◽  
Laser Light ◽  
Sol Gel ◽  
Surface Scattering ◽  
Sapphire Substrates ◽  
Lanthanum Titanate ◽  
Propagation Losses ◽  
Low Refractive Index

ABSTRACTLead lanthanum titanate thin films have been prepared on MgO and sapphire substrates by sol-gel method. XRD analyses confirm that the PLT films fabricated on MgO(lOO) and c-plane sapphire substrates grow preferentially with (100) and (111) orientations, respectively. The PLT films with a high La content have a low refractive index due to the decrease of the refractive index anisotropy. The propagation losses in PLT films measured, using He-Ne laser light and the prism coupling method decrease as the La content increases. This is due to the reduction of the refractive index anisotropy and the surface scattering by the surface roughness as a function of La content in the film.

Preparation and Characterization of Ultralow Density Silica Aerogels by Acetonitrile Supercritical Drying

2012 ◽  
Vol 519 ◽  
pp. 83-86 ◽  
Author(s):  
Guang Wu Liu ◽  
Xing Yuan Ni ◽  
Bin Zhou ◽  
Qiu Jie Yu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Silica Aerogels ◽  
High Specific Surface Area ◽  
Molar Ratio ◽  
Sol Gel Process

This paper deals with the synthesis of ultralow density silica aerogels using tetramethyl orthosilicate (TMOS) as the precursor via sol-gel process followed by supercritical drying using acetonitrile solvent extraction. Ultralow density silica aerogels with 6 mg/cc of density was made for the molar ratio by this method. The microstructure and morphology of the ultralow density silica aerogels was characterized by the specific surface area, SBET, SEM, and the pore size distribution techniques. The results show that the ultralow density silica aerogel has the high specific surface area of 812m2/g. Thermal conductivities at desired temperatures were analyzed by the transient plane heat source method. Thermal conductivity coefficients of silica aerogel monoliths changed from 0.024 to 0.043W/ (m K) as temperature increased to 400°C, revealed an excellent heat insulation effect during thermal process.

Quantum State in Fabricating Silica Antireflective Coatings

2012 ◽  
Vol 271-272 ◽  
pp. 247-250
Author(s):  
Rui Min Jin ◽  
Zhi Duan Cai ◽  
Li Min Cang ◽  
Tao Yan
Keyword(s):  
Refractive Index ◽  
Quantum State ◽  
Glass Substrate ◽  
Sol Gel ◽  
Sio2 Film ◽  
Quantum States ◽  
Antireflective Coating ◽  
Antireflective Coatings ◽  
Coating Films ◽  
Sol Gel Process

Based on TEOS system and sol-gel process, together with catalysts, Antireflective coating films prepared by sol—gel on glass substrate have been processed by rapid thermal annealing (RTA). the refractive index and thinkness of SiO2 film is exactly controlled. The films are characterized by ellipsometer and SEM respectively. The quantum states in these processions are found and discussed.

scholarly journals Comparison between the UV and X-ray Photosensitivities of Hybrid TiO2-SiO2 Thin Layers

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3730
Author(s):  
Maxime Royon ◽  
Francis Vocanson ◽  
Damien Jamon ◽  
Emmanuel Marin ◽  
Adriana Morana ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Sensors ◽  
Light Emitting Diode ◽  
Sol Gel ◽  
Dip Coating ◽  
Thin Layers ◽  
Light Sources ◽  
X Rays ◽  
X Ray ◽  
The Impact

The photo-induced effects on sol–gel-based organo TiO2-SiO2 thin layers deposited by the dip-coating technique have been investigated using two very different light sources: A light-emitting diode (LED) emitting in the UV (at 365 nm, 3.4 eV) and an X-ray tube producing 40 keV mean-energy photons. The impact of adding a photo-initiator (2,2-dimethoxy-2-phenylacetophenone-DMPA) on the sol–gel photosensitivity is characterized namely in terms of the photo-induced refractive index measured through M-line spectroscopy. Results show that both silica-titania sol–gel films with or without the photo-initiator are photosensitive to both photon sources. The induced refractive index values reveal several features where slightly higher refractive indexes are obtained for the sol–gel containing the photo-initiator. UV and X-ray-induced polymerization degrees are discussed using Fourier-transform infrared (FTIR) spectroscopy where the densification of hybrid TiO2-SiO2 layers is related to the consumption of the CH=C groups and to the decomposition of Si-OH and Si-O-CH3 bonds. X-rays are more efficient at densifying the TiO2-SiO2 inorganic and organic network with respect to the UV photons. Hard X-ray photolithography, where no cracks or damages are observed after intense exposition, can be a promising technique to design submicronic-structure patterns on TiO2-SiO2 thin layers for the building of optical sensors.

scholarly journals Preparation of ultra-broadband antireflective coatings for amplifier blast shields by a sol–gel method

2017 ◽  
Vol 5 ◽  
Author(s):  
Huai Xiong ◽  
Bin Shen ◽  
Zhiya Chen ◽  
Xu Zhang ◽  
Haiyuan Li ◽  
...  
Keyword(s):  
Refractive Index ◽  
Sol Gel ◽  
High Refractive Index ◽  
Dip Coating ◽  
Scratch Resistance ◽  
Fused Silica ◽  
Antireflective Coating ◽  
Antireflective Coatings ◽  
Average Residual ◽  
Low Refractive Index

A type of $\unicode[STIX]{x1D706}/4$–$\unicode[STIX]{x1D706}/4$ ultra-broadband antireflective coating has been developed using modified low refractive silica and high refractive silica layers by a sol–gel dip coating method for amplifier blast shields of the Shen Guang II high power laser facility (SG-II facility). Deposition of the first layer (high refractive index silica) involves baking at $200\,^{\circ }\text{C}$ in the post-treatment step. The second layer (low refractive index, $n=1.20$) uses low refractive index silica sol modified by acid catalysis. Thermal baking at temperatures no less than $500\,^{\circ }\text{C}$ for 60 min offers chemical stability, ethanol scratch resistance, and resistance to washing with water. The average residual reflection of dual-side-coated fused silica glass was less than 1% in the spectral range from 450 to 950 nm. Transmission gain has been evaluated by taking into account angular light, and the results show that the transmission gain increases with increasing light incidence. Even at $60^{\circ }$, the transmission spectrum of the broadband antireflective coating effectively covered the main absorption peak of Nd:glass.

The Monolithic Silica Aerogel Derived from MTMS/TEOS

2013 ◽  
Vol 364 ◽  
pp. 631-634
Author(s):  
Yu Xi Yu ◽  
Yong Chen
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Silica Aerogels ◽  
Synthesis And Characterization ◽  
Sol Gel Process

The experimental results on the synthesis and characterization of tetraethoxysilane (TEOS)/ methyltrimethoxysilane (MTMS)-based silica aerogels using two step sol-gel process via supercritical drying, are described. The obtained TEOS/MTMS-based aerogel showed properties of 0.1g/cm3 density, 95.5% porosity and 1070 m2/g specific surface area.

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