scholarly journals Mesoscale organization of titania thin films enables oxygen sensing at room temperature

2017 ◽  
Vol 5 (45) ◽  
pp. 11815-11823 ◽  
Author(s):  
Pietro Rassu ◽  
Luca Malfatti ◽  
Davide Carboni ◽  
Maria F. Casula ◽  
Sebastiano Garroni ◽  
...  
Keyword(s):  
Thin Films ◽  
Surface Area ◽  
Uv Irradiation ◽  
Room Temperature ◽  
Oxygen Sensor ◽  
Oxygen Sensing ◽  
Mesoporous Titania ◽  
Mesoporous Film ◽  
Titania Films

We developed an oxygen sensor based on mesoporous titania films working at RT under UV irradiation. Due to larger surface area and number of defects, the mesoporous film exhibits a response higher than dense titania.

scholarly journals Photo-Induced Super-hydrophilic Thin Films on Quartz Glass by UV Irradiation of Precursor Films Involving a Ti(IV) Complex at Room Temperature

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 348 ◽  
Author(s):  
Hsiang-Jung Wu ◽  
Kota Tanabe ◽  
Hiroki Nagai ◽  
Mitsunobu Sato
Keyword(s):  
Thin Films ◽  
Uv Irradiation ◽  
Quartz Glass ◽  
Room Temperature ◽  
Contact Angles ◽  
Chemical Components ◽  
Precursor Film ◽  
Dark Condition ◽  
Xps Spectra ◽  
Molecular Precursor

Photo-induced super-hydrophilic thin films were fabricated on a quartz glass substrate by ultraviolet (UV) irradiation of a molecular precursor film at room temperature. A molecular precursor film exhibiting high solubility to both ethanol and water was obtained by spin-coating a solution involving a Ti(IV) complex; this complex was prepared by the reaction of Ti(IV) alkoxide with butylammonium hydrogen oxalate and hydrogen peroxide in ethanol. Transparent and well-adhered amorphous thin films of 160–170 nm thickness were obtained by weak UV irradiation (4 mW·cm−2 at 254 nm) of the precursor films for over 4 h at room temperature. The resultant thin films exhibiting low refractive indices of 1.78–1.79 were mechanically robust and water-insoluble. The chemical components of the thin films were examined by means of Fourier transform-infrared (FT-IR) and X-ray photoelectron spectroscopy (XPS) spectra, focusing on the presence of the original ligands. The super-hydrophilic properties (evaluated based on the water contact angles on the surfaces) of the thin films after being kept in a dark condition overnight emerged when the aforementioned UV-light irradiation was performed for 10 min. It was additionally clarified that the super-hydrophilicity can be photo-induced repeatedly by UV irradiation for 10 min (indicated by a contact angle smaller than 4°) even after the hydrophilic level of the thin films had once been lowered by being in a dark condition for 4 h.

Oxygen sensor utilizing ultraviolet irradiation assisted ZnO nanorods under low operation temperature

RSC Advances ◽  
2014 ◽  
Vol 4 (95) ◽  
pp. 52903-52910 ◽  
Author(s):  
Chen-Shiun Chou ◽  
Yung-Chen Wu ◽  
Che-Hsin Lin
Keyword(s):  
Uv Irradiation ◽  
Ultraviolet Irradiation ◽  
High Performance ◽  
Oxygen Sensor ◽  
Oxygen Sensing ◽  
Zno Nanorods ◽  
Zno Film ◽  
Working Temperature ◽  
Operation Temperature

This paper presents a novel ultraviolet (UV) irradiation assisted nanostructured ZnO film for high performance oxygen sensing under a low working temperature.

Low-Temperature Fabrication of Mesoporous Titania Thin Films

MRS Advances ◽  
2017 ◽  
Vol 2 (43) ◽  
pp. 2315-2325 ◽  
Author(s):  
Lin Song ◽  
Volker Körstgens ◽  
David Magerl ◽  
Bo Su ◽  
Thomas Fröschl ◽  
...  
Keyword(s):  
Low Temperature ◽  
Uv Irradiation ◽  
Sol Gel ◽  
Composite Films ◽  
Grazing Incidence ◽  
Mesoporous Titania ◽  
Vis Spectroscopy ◽  
Titania Films ◽  
Polymer Template ◽  
Sol Gel Synthesis

ABSTRACTMesoporous titania films are prepared via the polymer-template assisted sol-gel synthesis at low temperatures, using the titania precursor ethylene glycol-modified titanate (EGMT) and the diblock copolymer polystyrene-block-polyethyleneoxide (PS-b-PEO). UV-irradiation is chosen as a low temperature technique to remove the polymer template and thereby to obtain titania sponge-like nanostructures at processing temperatures below 100 °C. After different UV irradiation times, ranging for 0 h to 24 h, the surface and inner morphologies of the titania films are studied with scanning electron microscopy (SEM) and grazing incidence small-angle x-ray scattering (GISAXS), respectively. The evolution of the band gap energies is investigated using ultraviolet/visible (UV/Vis) spectroscopy. The findings reveal that 12 h UV-treatment is sufficient to remove the polymer template from the titania/PS-b-PEO composite films with a thickness of 80 nm, and the determined bad gap energies indicate an incomplete crystallization of the titania nanostructures.

Unusual Antibacterial Property of Mesoporous Titania Films: Drastic Improvement by Controlling Surface Area and Crystallinity

2010 ◽  
Vol 5 (9) ◽  
pp. 1978-1983 ◽  
Author(s):  
Hamid Oveisi ◽  
Simin Rahighi ◽  
Xiangfen Jiang ◽  
Yoshihiro Nemoto ◽  
Ali Beitollahi ◽  
...  
Keyword(s):  
Surface Area ◽  
Antibacterial Property ◽  
Mesoporous Titania ◽  
Titania Films

Highly crystalline and ordered nanoporous SnO2 thin films with enhanced acetone sensing property at room temperature

2015 ◽  
Vol 3 (41) ◽  
pp. 10819-10829 ◽  
Author(s):  
Shaofeng Shao ◽  
Hongyan Wu ◽  
Shimin Wang ◽  
Qiling Hong ◽  
Ralf Koehn ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Surface Area ◽  
Gas Sensor ◽  
Room Temperature ◽  
High Surface ◽  
High Surface Area ◽  
Sno2 Thin Films

A crystalline and ordered nanoporous SnO2 thin film, with high surface area, was designed, synthesized, and evaluated as gas sensor detecting VOCs. Notably, sensing film presented enhanced acetone-sensing performances at room temperature.

Silver Nanoparticle-Based Arrays into Mesoporous Thin Films Structures for Photoelectronic Circuits

2019 ◽  
Vol 15 (3) ◽  
pp. 304-308
Author(s):  
Diana Catherine Delgado González ◽  
Andrés Di Donato ◽  
Paolo Nicolas Catalano ◽  
Martín Gonzalo Bellino
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Silver Nanoparticles ◽  
Ag Nanoparticles ◽  
Sol Gel ◽  
Oxide Thin Film ◽  
Localized Surface Plasmon ◽  
Mesoporous Titania ◽  
Mesoporous Film ◽  
Mesoporous Thin Films

Background: Silver nanosystems have attracted considerable attention for numerous applications in optoelectronics. The localized surface plasmon of silver nanoparticles embedded into mesoporous titania gives rise to an enhancement of local optical field in the vicinity of Ag nanoparticles which act as efficient light-trapping components, resulting in a visible wavelength-dependent photocurrent. Objective: In this paper, we synthetized patterned nanocomposites formed by titania mesoporous thin films loaded with alkanethiol functionalized Ag nanoparticles and we demonstrated that these stable and accessible nanostructures possess a photocurrent response. Method: Mesoporous thin films are created by combining sol-gel synthesis and template selfassembly. Based on a photolithography technique, silver nanoparticles were selectively photodeposited and then stabilized with octanethiols. Current vs. voltage curves with and without light were compared, where selective light wavelength measurements were achieved by using visible bandpass filters. The optofluidic behavior was evaluated by placing a drop of solutions on the mesoporous film. Results: We demonstrate photocurrent in these mesoporous thin film structures decorated with chemistabilized Ag nanoparticle-based conductive arrays, with significantly enhanced photocurrent peak at the plasmon resonant wavelength around 540 nm. Our findings offer a possibility to perform improved fluid detection with silver-mesoporous titania electronic devices. Conclusion: We showed that an optofluidic sensitive nanocomposite circuit consisting of alkanethiol- functionalized metal nanoparticles embedded in a mesoporous oxide thin film matrix can be produced.

Thermal Conductivity of Highly Ordered Amorphous and Crystalline Mesoporous Titania Thin Films

2010 ◽  
Author(s):  
Thomas Coquil ◽  
Laurent Pilon ◽  
Christian Reitz ◽  
Torsten Brezesinski ◽  
Joseph E. Nemanick ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermal Conductivity ◽  
Film Thickness ◽  
Pore Size ◽  
Wall Thickness ◽  
Sol Gel ◽  
Atomic Scale ◽  
Mesoporous Titania ◽  
Titania Films ◽  
The Cross

This paper reports the cross-plane thermal conductivity of amorphous and crystalline templated mesoporous titania thin films synthesized by evaporation-induced self-assembly. Both sol-gel and nanocrystal-based films were considered, with respective average porosities of 30% and 35%. The pore diameter ranged from 7 to 25 nm and film thickness from 60 to 370 nm while the average wall thickness varied from 3 to 25 nm. Nanocrystals in crystalline mesoporous films featured diameters between 9 and 13 nm. The thermal conductivity was measured at room temperature using the 3ω method. The experimental setup and the associated analysis were validated by comparing the thermal conductivity measurements with data reported in the literature for dense titania films with thickness ranging from 95 to 1000 nm. The cross-plane thermal conductivity of the amorphous mesoporous titania thin films did not show strong dependence on pore size, wall thickness, or film thickness. This can be attributed to the high atomic scale disorder of amorphous materials. Heat is thus mainly carried by localized non-propagating vibrational modes. The average thermal conductivity of the amorphous mesoporous titania films was identical to that of the nanocrystal-based films and equal to 0.37 W/m.K. Thermal conductivity of sol-gel crystalline mesoporous titania thin films was significantly larger than that of their amorphous counterparts. It also depended on the organic template used to make the films. The results indicated that the pore size was not an important factor. Instead thermal conductivity depended only on porosity, crystallinity, nanocrystal size and connectivity.

Studies on Water in the Hydration Chamber of a Modified Electron Microscope

1970 ◽  
Vol 28 ◽  
pp. 544-545
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Electron Microscope ◽  
Steady State ◽  
Room Temperature ◽  
Small Mass ◽  
Equilibrium Pressure ◽  
Biological Objects ◽  
Mechanical Pump ◽  
Differential Pumping

Use of the electron microscope to examine wet objects is possible due to the small mass thickness of the equilibrium pressure of water vapor at room temperature. Previous attempts to examine hydrated biological objects and water itself used a chamber consisting of two small apertures sealed by two thin films. Extensive work in our laboratory showed that such films have an 80% failure rate when wet. Using the principle of differential pumping of the microscope column, we can use open apertures in place of thin film windows.Fig. 1 shows the modified Siemens la specimen chamber with the connections to the water supply and the auxiliary pumping station. A mechanical pump is connected to the vapor supply via a 100μ aperture to maintain steady-state conditions.

Interactions Between Al and Cr Thin Films

1976 ◽  
Vol 34 ◽  
pp. 638-639
Author(s):  
R. M. Anderson ◽  
T. M. Reith ◽  
M. J. Sullivan ◽  
E. K. Brandis
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Vacuum System ◽  
Processing Temperature ◽  
Diffusion Couples ◽  
Electronic Circuits ◽  
Intermetallic Formation ◽  
Si Substrates ◽  
Aluminum Silicon

Thin films of aluminum or aluminum-silicon can be used in conjunction with thin films of chromium in integrated electronic circuits. For some applications, these films exhibit undesirable reactions; in particular, intermetallic formation below 500 C must be inhibited or prevented. The Al films, being the principal current carriers in interconnective metal applications, are usually much thicker than the Cr; so one might expect Al-rich intermetallics to form when the processing temperature goes out of control. Unfortunately, the JCPDS and the literature do not contain enough data on the Al-rich phases CrAl7 and Cr2Al11, and the determination of these data was a secondary aim of this work.To define a matrix of Cr-Al diffusion couples, Cr-Al films were deposited with two sets of variables: Al or Al-Si, and broken vacuum or single pumpdown. All films were deposited on 2-1/4-inch thermally oxidized Si substrates. A 500-Å layer of Cr was deposited at 120 Å/min on substrates at room temperature, in a vacuum system that had been pumped to 2 x 10-6 Torr. Then, with or without vacuum break, a 1000-Å layer of Al or Al-Si was deposited at 35 Å/s, with the substrates still at room temperature.

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