This work presents an investigation on UV radiation on conductive copolymer regio-regular poly(3-hexyltiophene) (rr- P3HT) and its mixture with zinc oxide nanomaterial as an organic-inorganic blend, which was used as a sensing layer for organic thin film transistor or chemoresistor for gas sensing. Morphology like sample roughness, zinc oxide particles distribution and electrical properties were measured of obtained thin film deposited on TFT substrate using airbrush method. The study shows that there is a significant influence on operating parameters of OTFT by the irradiation of UV light. Given results shows the possibility of using such polymer blend in the implementation of gas sensing applications.
In this paper, we are showing that the reduced graphene oxide could be used as a sensing layer in a chemoresitive gas sensors. The results of the investigation during which the sensing structure was affected by hydrogen and nitrogen dioxide in nitrogen and synthetic air in various temperatures are presented. We have observed that in certain temperature range, the resistance of the sensing structure was increased when hydrogen was in the gas mixture and was decreased when nitrogen dioxide was in the mixture, compared to the state without both gases. Moreover, we are showing that the humidity has no influence for the resistance of structure during the measurements with hydrogen. The measurements of the resistance has also been supplemented by the images of the structure obtained using scanning electron microscopy.
In this paper optical properties of silk fibroin (SF) thin films obtained via spin coating method are investigated. Work concentrates on the experimental examination of influence of relative humidity (RH) in the range of 7-90% in air on the changes of SF refractive index, thickness and optical path at room temperature. Spectral ellipsometry and interference methods are used for the SF thin films optical properties measurements. The sensing structure response value, response time and recovery time are presented. The results shows that RH significantly influenced the SF thin films thickness and refractive index what should be taken into account during the designing of optical devices based on SF. It also shows that SF thin films are promising material for room temperature RH sensors.
KEYWORDS: Sensors, Zinc oxide, Nanostructures, Ultraviolet radiation, Gas sensors, Scanning electron microscopy, Raman spectroscopy, Transducers, Temperature metrology, Near ultraviolet
The paper presents gas sensors based on ZnO nanostructures, which were obtained from zinc acetate in a very simple and repeatable process. Obtained structures were characterised using Raman spectroscopy and scanning electron microscopy. The ZnO nanostructures were applied as receptor layers in chemoresistive gas sensors onto interdigital transducers, using drop-coating. Sensor responses to low concentrations (1 ppm) of NO2 in the air, at different operating temperatures (room temperature 23°C (R.T.), 100°C and 200°C) and under different lighting conditions (dark conditions and UV irradiation – LED λ = 390 nm) are compared and discussed. Obtained results show that proper combination of elevated temperature and illumination by UV can improve sensor properties and allow it to operate at a lower temperature.
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.
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.
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.
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