In this paper, a simple combination of spin-coating fabrication techniques and cost-efficient polymer material for the fabrication of optoelectronic NO2 sensor was investigated. A surface plasmon resonance (SPR) sensor was fabricated by chitosan thin films immobilized on the gold plasmonic active layer. Sensing structures were formed on the glass slides covered 50 nm thick Au films by spin-coating method from liquid chitosan salt phase. Polymeric thin film work as sensitive elements and transducer to get optical response from environment at room temperature (RT).
In this paper, a simple combination of dip-coating fabrication techniques and cost-efficient copolymer grafted
phthalocyanine material for the fabrication of fiber optic NO2 sensor was investigated. A fiber optic sensor was
fabricated by organic thin films immobilized on the end-face of an optical fiber. Sensing nanostructure were formed on
the end-face of an optical fiber by dip-coating method from liquid phase. Polymeric thin film work as sensitive elements
and transducer to get optical response and feedback from environments, in which optical fibers are employed to work as
signal carrier.
In this paper I report the preparation and characterisation of an improved hydrogen gas sensor with a better sensitivity, using an amorphous thin WO3 film covered Pd film. Using a very sensitive optical sensing technique, such as the interference phenomena and a special configuration of the sensing structure were obtained interested results showing the influence of H2 gas on the optical sensor response. I present the design and results for an interferometric fiber optic hydrogen gas sensor, the Intrinsic Fabry-Perot Interferometer (IFPI), which uses the changing properties of layered interferometric sensing structure Pd/WO3 to detect hydrogen gas concentrations in the 500 – 2,000 ppm in synthetic dry air, with the working temperature at 80 °C in the presence of CH4.
This work presents an investigation on conductive graft comb copolymer like SILPEG CH9 with carbon materials like graphite oxide or reduced graphite oxide. Morphology and optical properties like sample roughness, graphite oxide particles distribution, optical transmittance were measured of obtained thin films deposited on glass substrate using spin coating method. The study showed that obtained thin films are repeatable, convenient to process, and their parameters can be easy changed by the spin rate regulation during the deposition. Given results shows the possibility of using such polymer blend in the implementation of organic photovoltaic cells and different optoelectronics applications.
In this paper graft copolymer of poly(3-hexylthiophene) and poly(ethylene) glycol on the polymethylsiloxane core are investigated as a receptor material for resistance gas sensor. Sensor response to 5 ppm of NO2 and its recovery after the interaction with NO2 are studied at different conditions: room temperature (RT), RT with ultraviolet (UV) radiation and at elevated temperature (50 °C). Results shows that sensor regeneration occurred faster at RT with UV than at 50 °C in dark conditions. The sensor response at RT is also higher than at 50 °C. The mixed operation conditions, namely dark conditions for adsorption and UV for desorption, provides high sensor response (3590% for 5 ppm of NO2) and relatively good regeneration (250% deviation from base-line after 30 min). Thanks to this investigated graft copolymers are promising receptor materials for chemical NO2 sensors operating at RT.
In this paper we propose low cost and easy in development fully working dye-sensitized solar cell module made with use of a different sensitizing dyes (various anthocyanins and P3HT) for increasing the absorption spectrum, transparent conducting substrates (vaccum spattered chromium and gold), nanometer sized TiO2 film, iodide and methyl viologen dichloride based electrolyte, and a counter electrode (vaccum spattered platinum or carbon). Moreover, some of the different technologies and optimization manufacturing processes were elaborated for energy efficiency increase and were presented in this paper.
The paper presents the results of numerical analyses of the surface acoustic wave (SAW) gas sensor based on WO3 layer with a catalytic nanolayer of Pd. The changes of SAW velocity vs. the surface electrical conductivity of the sensing layer is a essence of sensors of this kind. The conductivity of the porous sensoric layer which is deposited on a piezoelectric waveguide depends on the profile of concentration of gaseous molecules diffused inside the sensing layer. The Knudsen’s model of gas diffusion was used. Results of numerical analysis of the effect of the gaseous CH4 in air environment in the WO3 sensoric layer have been shown. The results of numerical analysis allow to select conditions of the SAW sensor, including the morphology of the sensor layer, its thickness and operating temperature. Some numerical results were verified by means of experimental studies.
It has developed a simple fiber optic sensor that is used to detection and measure concentration of water vapour in the air. The operating principle of the sensor is discussed in this work, and it was noticed that the wavelength positions of the reflectance peaks change with the concentration of H2O molecules. The sensor has been successfully used to monitor relative humidity of the air. The sensor utilizes a layered Fabry-Perot interferometric sensing structure. This structure was fabricated on the end of standard multi-mode fiber optic and includes Nafion® sensing film. The fiber optic hygrometer was tested for measurement of relative humidity in the range of 10-80% in air. SHT75 sensor (Sensirion Corp.) was used as reference sensor for control humidity level and temperature of gas mixture.
The surface plasmon resonance (SPR) is very sensitive, and so is the optical technique used in chemical sensing. The angle of incident of light at which a resonant effect is observed, as well as the dip of a resonant are very sensitive to variations of the optical parameters of the medium on a surface-active plasmon metal layer. In this work a novel combcopolimer of regioregular poly-3-hexylothiophene (rr-P3HT) and is studied as a gas (NO2) sensing material. Gas sensing properties of this material is examined using SPR technique at room temperature.
An optical sensor of ammonia gas, based on the surface plasmon resonance (SPR) method has been investigated. The surface plasmon resonance (SPR) is very sensitive, and so is the optical technique used in chemical sensing. The angle of incident of light at which a resonant effect is observed, as well as the dip of a resonant are very sensitive to variations of the optical parameters of the medium on a surface-active plasmon metal layer. The sensing structures were made as follows. Gold layers were coated by means of vacuum evaporation on a substrate, 1 mm thick, made of a BK7 glass slide. The thickness of Au was about 48 nm. An active sensor layer of WO3 was deposited by thermal evaporation on the gold film while a Nafion"R" film was coated by means of the spin-coating method. The sensing structures were coupled on immersion oil with a prism coupler. A change of the intensity of light of the plasmon dip was observed when chemical active films (WO3 or Nafion"R") were exposed to varying concentrations of NH3. Optical ammonia gas sensors display a very fast response time and a fast regeneration time at room temperature.
The paper presents an optical-fiber hydrogen sensor. The sensor utilises a layered Fabry-Perot interferometer and includes gasochromic metal oxides (V2O5, Nb2O5, CeO2). The structure contains at the end a multi-mode optical fiber as the sensing element. The sensor permits to detect and to measure the concentration of hydrogen in a gaseous medium.
A comparison of the properties of selected gasochromic metal oxides in the interferometric sensor structures has been presented.
The paper presents a layered sensing structure that permits to detect and to measure the concentration of hydrogen in a gaseous medium. This metal-dielectric-metal structure is a layered Fabry-Perot interferometer. The resonant cavity is made of WO3. The choice of just this material was dictated by its chemochromatic properties, i.e. the change of the optical properties due to the absorption of atomic hydrogen. In result of the absorption of H+ and e- the purely dielectric layer becomes a lost layer, displaying attenuation. The catalysis of molecular hydrogen to atomic hydrogen occurs in the palladium layer, which is also one of the mirrors of the interferometer. The measurement of the hydrogen concentration consists in the scanning of the angular variation of the interference peak position due to the absorption of hydrogen. The change of the peak position results from the change of the optical parameters of the Pd and WO3 layers.
The paper presents the results and way of measuring the dispersion of the complex refractive index of thin palladium layers in an atmosphere containing hydrogen with a concentration below the threshold of explosion (<4%). The measurements were carried out making use of exciting the surface plasmon wave.
The paper presents a way of determining the fundamental parameters of the design of a hydrogen sensor, the operation of which is based on the phenomenon of the resonance of surface plasmons (SPR - Surface Plasmon Resonance) in Kretschmann-Raether's system. The designed system has been realized. Its investigation results have also been presented.
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