Search results for "Cobalt phthalocyanine"
showing 4 items of 4 documents
Humidity effect on ammonia sensing properties of substituted and unsubstituted cobalt phthalocyanines
2012
In this paper, we studied the effect of humidity on the response of cobalt phthalocyanine-containing resistors to ammonia, in the ppm range. We pointed out the fact that, when alternating exposure periods with recovery periods, the humidity effect had to be carefully studied, in correlation with the flow variation. Thus, for a sulfonated cobalt phthalocyanine, the effect of NH(3) was totally screened as soon as the relative humidity (RH) was above 10%. On the contrary, when using unsubstituted cobalt phthalocyanine (CoPc) as sensing material, the sensors' response to NH(3) appears to be quite stable in a wide RH range, allowing a discrimination between 12, 25 and 50 ppm of NH(3) over the 10…
Microwave signature for gas sensing: 2005 to present
2015
Abstract We present here the development and the implementation of a technique of gas detection involving a microwave transduction method. The use of low-cost sensors based on microstrip or coplanar structures, adapted to the microwaves domain, allows the sensitive materials deposition under various forms. The purpose of the study is to assess the interest of microwave transduction for gas detection. The choice of the sensitive materials concerns materials widely used in the field of gas sensing: the metal oxides (SnO2 and TiO2) as well as molecular materials like cobalt phthalocyanine (CoPc). In this article we shall apply to explain the principles of the microwave transduction before appr…
Differential study of substituted and unsubstituted cobalt phthalocyanines for gas sensor applications
2011
Abstract The conductivity of CoPc (cobalt phthalocyanine) and Co[(SO3Na)2,3Pc] was measured under a flow of two different gases (NH3 and O3), during exposure/recovery cycles. It appears that the relative responses are linearly related to the concentration, in the 20–200 ppb range for O3 and in the 20–200 ppm range for NH3. Observed during time, the sensing parameters allow a qualitative understanding of the kinetics. The comparative study of those products under both different gases gave interesting results for sensor applications. Whereas CoPc is sensitive to both gases, its sulfonated counterpart is only sensitive to NH3.
Microwave-based gas sensor with phthalocyanine film at room temperature
2013
Abstract This work presents the development of a microwave gas sensor at room temperature. The design of the sensor includes a coplanar grounded wave guide where is deposited a molecular gas sensing material. In this study, the sensitive material is a thin layer of cobalt phthalocyanine (CoPc), sensitive to ammonia and toluene. Submitted to an electromagnetic incident wave in the microwave range, the sensor response is a reflected wave. In the presence of pollutant, the reflected wave shape is specific to the species concentrations. The results interpretation is led at each frequency by the evaluation of the reflected coefficient, which traduces the ratio between the reflected wave over the…