scholarly journals Spatially Ordered Matrix of Nanostructured Tin–Tungsten Oxides Nanocomposites Formed by Ionic Layer Deposition for Gas Sensing

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4169
Author(s):  
Gennady Gorokh ◽  
Natalia Bogomazova ◽  
Abdelhafed Taleb ◽  
Valery Zhylinski ◽  
Timur Galkovsky ◽  
...  
Keyword(s):  
Tungsten Oxide ◽  
Gas Sensing ◽  
Oxide Films ◽  
High Sensitivity ◽  
Anodic Alumina ◽  
Film Deposition ◽  
Silicon Substrates ◽  
Layer By Layer ◽  
Gas Sensitivity ◽  
Nanoporous Anodic Alumina

The process of layer-by-layer ionic deposition of tin-tungsten oxide films on smooth silicon substrates and nanoporous anodic alumina matrices has been studied. To achieve the film deposition, solutions containing cationic SnF2 or SnCl2 and anionic Na2WO4 or (NH4)2O·WO3 precursors have been used. The effect of the solution compositions on the films deposition rates, morphology, composition, and properties was investigated. Possible mechanisms of tin-tungsten oxide films deposition into the pores and on the surface of anodic alumina are discussed. The electro-physical and gas-sensitive properties of nanostructured SnxWyOz films have been investigated. The prepared nanocomposites exhibit stable semiconductor properties characterized by high resistance and low temperature coefficient of electrical resistance of about 1.6 × 10−3 K−1. The sensitivity of the SnxWyOz films to 2 and 10 ppm concentrations of ammonia at 523 K was 0.35 and 1.17, respectively. At concentrations of 1 and 2 ppm of nitrogen dioxide, the sensitivity was 0.48 and 1.4, respectively, at a temperature of 473 K. At the temperature of 573 K, the sensitivity of 1.3 was obtained for 100 ppm of ethanol. The prepared nanostructured tin-tungsten oxide films showed promising gas-sensitivity, which makes them a good candidate for the manufacturing of gas sensors with high sensitivity and low power consumption.

Structural Approach to Improve the Response Characteristics of Copper Phthalocyanine Thin Film-Based NO2Gas Sensor

1997 ◽  
Vol 488 ◽  
Author(s):  
Tadashi Nagasawa ◽  
Kenji Murakami ◽  
Kenzo Watanabe
Keyword(s):  
Copper Phthalocyanine ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Film Deposition ◽  
Gas Sensitivity ◽  
Vacuum Sublimation ◽  
Response Characteristics ◽  
Atomic Force ◽  
Film Microstructure ◽  
Sensing Characteristics

AbstractIn order to realize a high-sensitivity, low temperature operable NO2gas sensor, thin films of at-form copper phthalocyanine (α-CuPc) have been deposited by vacuum sublimation. In this study, we have attempted to improve the gas-sensing characteristics through a modification of the film microstructure. Firstly, the gas sensitivity is remarkably increased by an insertion of higher-sensitive layer (vanadyl Pc film) between the α-CuPc film and the glass substrate in the low gas concentration range. Secondly, a reversibility in cycles of gas doping and dedoping is improved by film deposition on hydrofluoric acid-treated substrate. It is found from atomic force microscope analyses that this phenomenon may be closely related to a modification of the film microstructure.

scholarly journals P1GS.13 - Tungsten Oxide Films with High Sensitivity to Nitric Oxide

2018 ◽  
Author(s):  
S. Krutovertsev ◽  
A. Tarasova ◽  
O. Ivanova ◽  
L. Krutovertseva
Keyword(s):  
Nitric Oxide ◽  
Tungsten Oxide ◽  
Oxide Films ◽  
High Sensitivity

Characterization of Self-Assembled SnO2 Nanoparticles for Fabrication of a High Sensitivity and High Selectivity Micro-Gas Sensor

2001 ◽  
Vol 707 ◽  
Author(s):  
R.C. Ghan ◽  
Y. Lvov ◽  
R.S. Besser
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
Sno2 Nanoparticles ◽  
High Sensitivity ◽  
Layer By Layer ◽  
Voltage Measurement ◽  
Material Technology ◽  
Nanoparticle Deposition ◽  
Nanoparticle Films ◽  
Self Assembled

ABSTRACTIn order to refine further the material technology for tin-oxide based gas sensing we are exploring the use of precision nanoparticle deposition for the sensing layer. Layers of SnO2 nanoparticles were grown on Quartz Crystal Microbalance (QCM) resonators using the layer-by-layer self-assembly technique. Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Electron Diffraction Pattern (EDP) analyses were performed on the self-assembled layers of SnO2 nanoparticles. The results showed that SnO2 nanoparticle films are deposited uniformly across the substrate. The size of the nanoparticles is estimated to be about 3-5 nm. Electrical characterization was done using standard current-voltage measurement technique, which revealed that SnO2 nanoparticle films exhibit ohmic behavior. Calcination experiments have also been carried out by baking the substrate (with self-assembled nanoparticles) in air at 350°C. Results show that 50%-70% of the polymer layers (which are deposited as precursor layers and also alternately in-between SnO2 nanoparticle monolayers) are eliminated during the process.

scholarly journals Sustained, Controlled and Stimuli-Responsive Drug Release Systems Based on Nanoporous Anodic Alumina with Layer-by-Layer Polyelectrolyte

2016 ◽  
Vol 11 (1) ◽  
Author(s):  
Maria Porta-i-Batalla ◽  
Chris Eckstein ◽  
Elisabet Xifré-Pérez ◽  
Pilar Formentín ◽  
J. Ferré-Borrull ◽  
...  
Keyword(s):  
Drug Release ◽  
Anodic Alumina ◽  
Layer By Layer ◽  
Stimuli Responsive ◽  
Nanoporous Anodic Alumina

scholarly journals Electrostatic Supercapacitors by Atomic Layer Deposition on Nanoporous Anodic Alumina Templates for Environmentally Sustainable Energy Storage

Coatings ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 403 ◽  
Author(s):  
Luis Fernández-Menéndez ◽  
Ana González ◽  
Víctor Vega ◽  
Víctor de la Prida
Keyword(s):  
Atomic Layer Deposition ◽  
Silicon Dioxide ◽  
Atomic Layer ◽  
Dielectric Materials ◽  
Anodic Alumina ◽  
Layer By Layer ◽  
Nanoporous Anodic Alumina ◽  
Low Leakage ◽  
Layer Deposition ◽  
Anodic Alumina Templates

In this work, the entire manufacturing process of electrostatic supercapacitors using the atomic layer deposition (ALD) technique combined with the employment of nanoporous anodic alumina templates as starting substrates is reported. The structure of a usual electrostatic capacitor, which comprises a top conductor electrode/the insulating dielectric layer/and bottom conductor electrode (C/D/C), has been reduced to nanoscale size by depositing layer by layer the required materials over patterned nanoporous anodic alumina membranes (NAAMs) by employing the ALD technique. A thin layer of aluminum-doped zinc oxide, with 3 nm in thickness, is used as both the top and bottom electrodes’ material. Two dielectric materials were tested; on the one hand, a triple-layer made by a successive combination of 3 nm each layers of silicon dioxide/titanium dioxide/silicon dioxide and on the other hand, a simple layer of alumina, both with 9 nm in total thickness. The electrical properties of these capacitors are studied, such as the impedance and capacitance dependences on the AC frequency regime (up to 10 MHz) or capacitance (180 nF/cm2) on the DC regime. High breakdown voltage values of 60 V along with low leakage currents (0.4 μA/cm2) are also measured from DC charge/discharge RC circuits to determine the main features of the capacitors behavior integrated in a real circuit.

Synthesis of Mesoporous Polyaniline-TiO2 Composite Microspheres for Gas Sensing Application

2013 ◽  
Vol 750-752 ◽  
pp. 1098-1103 ◽  
Author(s):  
Xiao Lan Song ◽  
Cheng Yin Yan ◽  
Shu Tao Huang ◽  
Ming Wan Zhang ◽  
Bai Yang Geng ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Amorphous State ◽  
High Sensitivity ◽  
Bet Surface Area ◽  
X Ray Diffraction ◽  
Gas Sensitivity ◽  
Facile Hydrothermal Method ◽  
Xrd Pattern ◽  
Composite Microspheres ◽  
Ft Ir

The mesoporous polyaniline (PANI)-TiO2composite microspheres were prepared by a facile hydrothermal method and characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) surface area. The XRD pattern suggested that PANI did not modify the crystal structure of TiO2whereas PANI exhibited amorphous state. The SEM of PANI-TiO2displayed for microspheres. The gas sensitivity of the PANI-TiO2hybrid was also studied. The as-prepared sample was sensitivity to ammonia and ethanol and showed good reversibility. The PANI-TiO2hybrid material exhibits high sensitivity (0.96) to ammonia (150ppm) when operates at 373K.

scholarly journals Optical Platform to Analyze a Model Drug-Loading and Releasing Profile Based on Nanoporous Anodic Alumina Gradient Index Filters

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 730
Author(s):  
Pankaj Kapruwan ◽  
Laura K. Acosta ◽  
Josep Ferré-Borrull ◽  
Lluis F. Marsal
Keyword(s):  
Real Time ◽  
Drug Loading ◽  
Anodic Alumina ◽  
Gradient Index ◽  
Layer By Layer ◽  
Nanoporous Anodic Alumina ◽  
Layer Deposition ◽  
Model Drug ◽  
Surface Modified ◽  
Cargo Molecule

In this work, a methodology that exploits the optical properties of the nanoporous anodic alumina gradient index filters (NAA-GIFs) has been developed and applied to evaluate in real time the release dynamics of a cargo molecule, acting as a model drug, filling the pores. NAA-GIFs with two photonic stopbands (PSBs) were prepared with one of its stop bands in the same absorption wavelength range of the cargo molecule, whereas the second stopband away from this absorption range. Numerical simulation and experiments confirm that the relative height of the high reflectance bands in the reflectance spectra of NAA-GIFs filled with the drug can be related to the relative amount of drug filling the pores. This property has been applied in a flow cell setup to measure in real-time the release dynamics of NAA-GIFs with the inner pore surface modified by layer-by-layer deposition of polyelectrolytes and loaded with the cargo molecule. The methodology developed in this work acts as a tool for the study of drug delivery from porous nanostructures.

Modified Epitaxial Graphene on SiC for Extremely Sensitive and Selective Gas Sensors

2016 ◽  
Vol 858 ◽  
pp. 1145-1148 ◽  
Author(s):  
Jens Eriksson ◽  
Donatella Puglisi ◽  
Carl Strandqvist ◽  
Rickard Gunnarsson ◽  
Sebastian Ekeroth ◽  
...  
Keyword(s):  
Gas Sensing ◽  
Chemical Interaction ◽  
Metal Oxide Nanoparticles ◽  
High Sensitivity ◽  
Thin Film Deposition ◽  
Epitaxial Graphene ◽  
Film Deposition ◽  
Pulsed Plasma ◽  
Monitoring And Control ◽  
Plasma Sputtering

Two-dimensional materials offer a unique platform for sensing where extremely high sensitivity is a priority, since even minimal chemical interaction causes noticeable changes in electrical conductivity, which can be used for the sensor readout. However, the sensitivity has to be complemented with selectivity, and, for many applications, improved response- and recovery times are needed. This has been addressed, for example, by combining graphene (for sensitivity) with metal/oxides (for selectivity) nanoparticles (NP). On the other hand, functionalization or modification of the graphene often results in poor reproducibility. In this study, we investigate the gas sensing performance of epitaxial graphene on SiC (EG/SiC) decorated with nanostructured metallic layers as well as metal-oxide nanoparticles deposited using scalable thin-film deposition techniques, like hollow-cathode pulsed plasma sputtering. It is demonstrated that under the right modification conditions the electronic properties of the surface remain those of graphene, while the surface chemistry can be tuned to improve sensitivity, selectivity and speed of response to several gases relevant for air quality monitoring and control, such as nitrogen dioxide, benzene, and formaldehyde.

scholarly journals Low-Temperature Synthesis and Gas Sensitivity of Perovskite-Type LaCoO3Nanoparticles

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
Lorenzo Gildo Ortiz ◽  
Héctor Guillén Bonilla ◽  
Jaime Santoyo Salazar ◽  
M. de la L. Olvera ◽  
T. V. K. Karthik ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Cobalt Nitrate ◽  
Gas Sensitivity ◽  
Tem Analysis ◽  
Operation Temperature ◽  
Transmission Electron ◽  
Colloidal Method ◽  
Perovskite Type

LaCoO3nanoparticles with perovskite-type structure were prepared by a microwave-assisted colloidal method. Lanthanum nitrate, cobalt nitrate, and ethylenediamine were used as precursors and ethyl alcohol as solvent. The thermal decomposition of the precursors leads to the formation of LaCoO3from a temperature of 500°C. The structural, morphological, and compositional properties of LaCoO3nanoparticles were studied in this work by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Pellets were manufactured in order to test the gas sensing properties of LaCoO3powders in carbon monoxide (CO) and propane (C3H8) atmospheres. Agglomerates of nanoparticles with high connectivity, forming a porous structure, were observed from SEM and TEM analysis. LaCoO3pellets presented a high sensitivity in both CO and C3H8at different concentrations and operating temperatures. As was expected, sensitivity increased with the gas concentration and operation temperature increase.

Phase evolution, microstructure, and gas-sensing characteristics of the Sb2O3–Fe2O3 system prepared by coprecipitation

2000 ◽  
Vol 15 (11) ◽  
pp. 2356-2363 ◽  
Author(s):  
Tianshu Zhang ◽  
P. Hing ◽  
Ruifang Zhang ◽  
Jiancheng Zhang ◽  
Young Li
Keyword(s):  
Surface Area ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Phase Evolution ◽  
Antimony Oxide ◽  
Area Measurement ◽  
Crystallite Growth ◽  
Gas Sensitivity ◽  
Experimental Conditions ◽  
Precursor Powders

Precursor powders with antimony-to-iron (Sb/Fe) atomic ratios ranging from 0 to 2.0 were prepared by chemical coprecipitation. The origin of enhanced gas-sensing behavior at a higher calcining temperature was investigated, based on phase evolution and microstructure characterized by means of thermal analysis, x-ray diffraction, Brunauer–Emmett–Teller surface area measurement, and electron microscopy. Only one iron–antimony oxide (i.e., FeSbO4) could be obtained under present experimental conditions. Pure FeSbO4 exhibited a high gas sensitivity, only when calcining temperature was below 600 °C. A rapid crystallite growth, as well as hard agglomeration, occurred in pure FeSbO4 powder calcined at 600–1000 °C, and thus led to poor gas-sensing behavior. However, there existed an optimal Sb/Fe ratio range (i.e., 0.25 to 0.65) in which crystallite growth of both α–Fe2O3 and FeSbO4 could be efficiently depressed up to 800 °C. The samples (with Sb/Fe ratio in the range 0.25–0.65) calcined at 600–800 °C displayed a high sensitivity to liquid petroleum gas due to their large specific surface area and poor crystallinity.

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