Preparation, characterization, and micropatterning of laser-dye-doped sol-gel films

2002 ◽  
Vol 17 (8) ◽  
pp. 2095-2098 ◽  
Author(s):  
A. Arena ◽  
S. Patanè ◽  
G. Saitta ◽  
G. Rizzo ◽  
S. Galvagno ◽  
...  
Keyword(s):  
Soft Lithography ◽  
Sol Gel ◽  
Film Surface ◽  
Optical Microscope ◽  
Infrared Range ◽  
Patterned Films ◽  
A Charge ◽  
Sol Gel Films ◽  
Sol Gel Synthesis ◽  
Micrometer Scale

Planar thin films of dye-doped silica were prepared by sol-gel synthesis. The optical properties of the films were characterized by transmittance measurements in the visible-infrared range and by photoluminescence. Micropatterns whose feature size was on the order of 2.4 μm, were imprinted on the film surface by a simple soft lithography approach. An optical microscope interfaced to a charge-coupled device camera was used to image the imprinted patterns and to analyze the patterned films photoluminescence. A sensitive spectral narrowing of the emission, which occurred only in micropatterned films, was attributed to the lateral confinement of the luminescence due to the micrometer-scale modulation of refractive index produced by the embossing procedure.

Sol-gel synthesis of textured lanthanum titanate thin films

2003 ◽  
Vol 18 (2) ◽  
pp. 357-362 ◽  
Author(s):  
Mary M. Sandstrom ◽  
Paul Fuierer
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Precursor Solution ◽  
Solution Concentration ◽  
Optical Measurements ◽  
Layered Perovskite ◽  
Orientation Factor ◽  
Anisotropic Structures ◽  
Sol Gel Films ◽  
Sol Gel Synthesis

Control over crystallographic orientation in thin films is important, particularly with highly anisotropic structures. Because of its ferroelectric nature, the layered perovskite La2Ti2O7 has interesting piezoelectric and electrooptic properties that may be exploited when films are highly textured. Sol-gel films with an orientation factor of greater than 95% were fabricated without relying on epitaxial (lattice-matching) growth from the substrate. Film orientation and crystallization were confirmed by x-ray diffraction, scanning electron microscopy, atomic force microscopy, and optical measurements. The particle sizes in all precursor solutions were measured by dynamic light scattering experiments. Experimental results indicate that film orientation is a function of precursor solution concentration, size of the molecular clusters in the solution, and film thickness.

Characterization of the Surface Area and Porosity of Sol-Gel Films Using Saw Devices

1988 ◽  
Vol 121 ◽  
Author(s):  
Gregory C. Frye ◽  
Antonio J. Ricco ◽  
Stephen J. Martin ◽  
C. Jeffrey Brinker
Keyword(s):  
Pore Size ◽  
Surface Area ◽  
Adsorption Isotherms ◽  
Sol Gel ◽  
Film Surface ◽  
Nitrogen Adsorption ◽  
Porous Films ◽  
Pore Size Distributions ◽  
Test Film ◽  
Sol Gel Films

ABSTRACTA novel technique for accurately obtaining nitrogen adsorption isotherms on thin porous films has been developed. These isotherms are useful for characterizing the surface area and pore size distribution of porous samples. The sensitivity to adsorbed nitrogen is increased by several orders of magnitude over conventional techniques by forming the test film on the substrate of a surface acoustic wave (SAW) device. This device functions as a microbalance able to detect less than 100 pg/cm2 of film. Surface areas and pore size distributions calculated from adsorption isotherms obtained with this technique on silicate sol-gel films are compared to those for bulk samples prepared from similar sol-gel solutions.

Alumina Sol-Gel Films and Alodine Films on Al 2024 Alloy

2011 ◽  
Vol 356-360 ◽  
pp. 364-367
Author(s):  
Qi Zhou ◽  
Xuan Xiao ◽  
Da Li Zhao ◽  
En Jun Song
Keyword(s):  
Corrosion Resistance ◽  
Aluminium Alloy ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Film Surface ◽  
Corrosion Current ◽  
Promising Alternative ◽  
Gel Film ◽  
Alumina Sol ◽  
Sol Gel Films

Development of the sol-gel films for painting pretreatment of aluminium alloy is to replace bichromate conversion films such as Alodine. Corrosion resistance of Alodine film and sol-gel film were evaluated through potentiodynamic polarization curves, electrochemical impedance spectroscopy, salt spraying and acidic dropping solution. Sol-gel film is almost the same as Alodine film at the film surface density, salt spraying resistance and adhesion with painting coating. Changing color times of dropping solution on sol-gel film is shorter than Alodine film. But the corrosion current of sol-gel film is lower than Alodine and the impedance value is higher than Alodine in 35g/L NaCl solution. Mechanism of corrosion resistance of alumina sol-gel film is that the cathode reaction and anodic reactions are restrained by sol-gel film in the Cl- corrosive medium. The EIS of sol-gel film consisted of only a single capacitive arc with one time constant. Sol-gel coating can prevent or delay the corrosive solution from infiltrating the substrate for its better isolation function, thus protecting 2024 aluminium alloy from corrosion. Sol-gel films can improve corrosion resistance of aluminum alloy and have the same adhesion as Alodine film. It will be a promising alternative pretreatment for aluminum alloys prior to painting.

Sol-gel synthesis of rare-earth-doped fluoride glass thin films

1996 ◽  
Vol 11 (4) ◽  
pp. 841-849 ◽  
Author(s):  
John Ballato ◽  
Matthew Dejneka ◽  
Richard E. Riman ◽  
Elias Snitzer ◽  
Weimin Zhou
Keyword(s):  
Thin Films ◽  
Rare Earth ◽  
Sol Gel ◽  
Fluoride Glass ◽  
Silicon Substrates ◽  
Fluorescence Studies ◽  
Glass Rods ◽  
Sol Gel Films ◽  
Sol Gel Synthesis ◽  
Rare Earth Doped

This paper describes ZBLA fluoride glass thin films produced via an inexpensive, low-temperature reactive atmosphere sol-gel approach. Luminescence from erbium at 1.55 μm has been observed in x-ray-amorphous doped films deposited on calcium fluoride, polyimide, sapphire, and silicon substrates. Fluorescence studies of the erbium 4S3/2 → 4I13/2 transition, a characteristic emission for a reduced phonon energy host, were conducted for both sol-gel-derived films and conventionally prepared glass rods. The peak intensity observed from the sol-gel films was blue-shifted by 16 nm with a FWHM value approximately half that measured for the melt-quenched rods. Excitation studies indicate that, unlike conventionally prepared glasses, sol-gel materials suffer from nonradiative relaxation of the 4S3/2 excited state to the 4I9/2 level, where subsequent radiative emission to the 4I15/2 ground state occurs. The proposed source of the quenching mechanism are remnant species inherent to the sol-gel process. While this causes the luminescence behavior of rare-earth-doped sol-gel-derived fluoride materials to be similar to oxide hosts, these remnant species modify the branching ratios, resultantly leading to a novel 824 nm emission when excited at 488 nm.

Fabrication of heteropolyoxometalate-based photochromic inorganic–organic nanocomposites

2001 ◽  
Vol 16 (8) ◽  
pp. 2256-2263 ◽  
Author(s):  
Tie Rui Zhang ◽  
Wei Feng ◽  
Chun Yan Bao ◽  
Ran Lu ◽  
Xin Tong Zhang ◽  
...  
Keyword(s):  
Sol Gel ◽  
Organic Matrix ◽  
Transfer Model ◽  
X Ray Diffraction ◽  
Transparent Films ◽  
Spin Resonance ◽  
Gel Film ◽  
A Charge ◽  
Sol Gel Films ◽  
Charge Transfer Model

A series of photochromic sol-gel films are prepared through entrapping tungsten heteropolyoxometallates (PW12O403−, SiW12O404−) and molybdenum heteropolyoxometallate (PMo12O403−) into a kind of inorganic–organic matrix cohydrolyzed from tetraethylorthosilicate and 3-aminopropyltriethoxysilane. The films show reversible photochromicity. Irradiated with ultraviolet light, the transparent films change from colorless to blue. Then, bleaching occurs when the films are in contact with air or O2 in the dark. The Keggin-type polyanions interact with R–NH3+ cations strongly, and thus disperse uniformly in the sol-gel matrix, as proved by Fourier transform infrared spectra and x-ray diffraction. The molybdenum heteropolyoxometallate sol-gel film has higher photochromic efficiency and much slower bleaching than its counterparts of tungsten heteropolyoxometallate. A charge-transfer model which is supported by electron spin resonance and related literature [T. Yamase, Chem. Rev. 98, 307, (1998)] is put forth to explain the above experimental results.

Fast and Simple Specimen Preparation for TEM Studies of Oxide Films Deposited on Silicon Wafers

2009 ◽  
Vol 15 (1) ◽  
pp. 15-19 ◽  
Author(s):  
Valentin S. Teodorescu ◽  
Marie-Genevieve Blanchin
Keyword(s):  
Sol Gel ◽  
Film Surface ◽  
Specimen Preparation ◽  
Silicon Substrates ◽  
Simple Method ◽  
Plan View ◽  
Transmission Electron ◽  
High Resolution Images ◽  
Sol Gel Films ◽  
Si Wafer

AbstractWe present a fast and simple method to prepare specimens for transmission electron microscopy studies of oxide thin films deposited on silicon substrates. The method consists of scratching the film surface using a pointed diamond tip, in a special manner. Small and thin fragments are then detached from the film and its substrate. Depending on the scratching direction, the fragments can be used for plan-view or cross-section imaging. High-resolution images can be also obtained from thin edges of the film fragments. The method is demonstrated in the case of HfO2 sol-gel films deposited on [100] Si wafer substrates.

BARIUM TITANATE FILMS FOR ELECTRONIC APPLICATIONS: STRUCTURAL AND DIELECTRIC PROPERTIES

2008 ◽  
Vol 15 (03) ◽  
pp. 237-244 ◽  
Author(s):  
S. RIAZ ◽  
S. SHAMAILA ◽  
B. KHAN ◽  
S. NASEEM
Keyword(s):  
Dielectric Constant ◽  
Room Temperature ◽  
Structural Changes ◽  
Sol Gel ◽  
Optical Microscope ◽  
Loss Angle ◽  
Sem Images ◽  
Dielectric Constant And Loss ◽  
Cu Substrates ◽  
Sol Gel Films

Synthesis of the precursors, using research grade materials and locally available facilities, is optimized in order to obtain a suitable sol for BaTiO 3. The optimally synthesized BaTiO 3 sol is then spun onto Cu substrates to obtain films of thickness ~0.5 μm. The deposited BaTiO 3 films are heated up to a temperature of 300°C. Surface and structural changes, with heating, are observed by optical microscope, scanning electron microscope, atomic force microscope, and X-ray diffraction. The surface cracked in some cases but is generally uniform, as seen with SEM and AFM, in case of optimized conditions. The SEM images reveal large crystallites, which are correlated to the XRD observation of tetragonal perovskite structure of these sol–gel films. The AFM scan, however, shows an rms roughness of 35.6 nm for an area of 3 μm × 3 μm. Tetragonal perovskite BaTiO 3 is obtained at a temperature of as low as 300°C. The dielectric constant and loss angle, in the 30 Hz–3 MHz range, are calculated at room temperature and up to 200°C. At high frequencies the dielectric constant (~290) and loss angle (~2 × 10-6) values indicate the usefulness of such films in electronic applications. The leakage current is also measured at room temperature and a conductivity of 2.0 × 10-15 S/cm is obtained.

scholarly journals Holographic sol–gel monoliths: optical properties and application for humidity sensing

2018 ◽  
Vol 5 (5) ◽  
pp. 172465 ◽  
Author(s):  
Daniil A. Ilatovskii ◽  
Valentin Milichko ◽  
Alexander V. Vinogradov ◽  
Vladimir V. Vinogradov
Keyword(s):  
Soft Lithography ◽  
Sol Gel ◽  
Humidity Sensors ◽  
Additional Equipment ◽  
Wavy Structure ◽  
Multi Walled Carbon Nanotubes ◽  
Doped Titania ◽  
Sol Gel Synthesis ◽  
Walled Carbon Nanotubes ◽  
First Time

Sol–gel monoliths based on SiO 2 , TiO 2 and ZrO 2 with holographic colourful diffraction on their surfaces were obtained via a sol–gel synthesis and soft lithography combined method. The production was carried out without any additional equipment at near room temperature and atmospheric pressure. The accurately replicated wavy structure with nanoscale size of material particles yields holographic effect and its visibility strongly depends on refractive index (RI) of materials. Addition of multi-walled carbon nanotubes (MWCNTs) in systems increases their RI and lends absorbing properties due to extremely high light absorption constant. Further prospective and intriguing applications based on the most successful samples, MWCNTs-doped titania, were investigated as reversible optical humidity sensor. Owing to such property as reversible resuspension of TiO 2 nanoparticles while interacting with water, it was proved that holographic xerogels can repeatedly act as humidity sensors. Materials which can be applied as humidity sensors in dependence on holographic response were discovered for the first time.

Sol-Gel Synthesis of Functional Nanostructured Materials for Electronic Devices

2015 ◽  
Vol 1117 ◽  
pp. 164-167
Author(s):  
Alexander Rogachev ◽  
Dumitru Luca ◽  
Vladimir Gaishun ◽  
Alina Semchenko ◽  
Vitaly Sidsky ◽  
...  
Keyword(s):  
Nanostructured Materials ◽  
Crystallization Behavior ◽  
Electronic Devices ◽  
Sol Gel ◽  
Structural Features ◽  
Memory Devices ◽  
Gel Method ◽  
Non Volatile Memory ◽  
Sol Gel Films ◽  
Sol Gel Synthesis

The possibility of functional nanostructured materials for electronic devices synthesis by sol-gel method have been discussed such as ferroelectrics (SrBi2(TaxNb1-x)2O9) , ferromagnetics (FexCoyOz) and semiconductors (ZnO). The structural features of the surface (AFM), crystallization behavior (XRD) during the heating and properties of synthesized films are discussed. Achieved parameters suggest the possibility of using synthesized SBTN sol-gel films in non-volatile memory devices, semiconductors active ZnO layers in solar sells, ferromagnetics FexCoyOzfilms in radioabsorbing covers.

Hybrid Micro-Optical Sensors via Sol-Gel Soft Lithography

2000 ◽  
Vol 628 ◽  
Author(s):  
Mark A. Clarner ◽  
Michael J. Lochhead
Keyword(s):  
Optical Sensors ◽  
Soft Lithography ◽  
Sol Gel ◽  
Silica Gels ◽  
Ph Sensing ◽  
Ambient Conditions ◽  
Sensor Applications ◽  
Patterned Structures ◽  
Biological Functionality ◽  
Indicator Dyes

ABSTRACTOrganically modified silica gels and dye-doped silica gels have been patterned into micrometer-scale structures on a substrate using micro molding in capillaries (MIMIC). This approach is from a class of elastomeric stamping and molding techniques collectively known as soft lithography. Soft lithography and sol-gel processing share attractive features in that they are relatively benign processes performed at ambient conditions, which makes both techniques compatible with a wide variety of organic molecules, molecular assemblies, and biomolecules. The combination of sol-gel and soft lithography, therefore, holds enormous promise as a tool for microfabrication of materials with optical, chemical, or biological functionality that are not readily patterned with conventional methods. This paper describes our investigation of micro-patterned organic-inorganic hybrid materials containing indicator dyes for microfluidic sensor applications. Reversible colorimetric pH sensing via entrapped reagents is demonstrated in a prototype microfluidic sensor element. Patterned structures range from one to tens of micrometers in cross-section and are up to centimeters in length. Fundamental chemical processing issues associated with mold filling, cracking and sensor stability are discussed.

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