0000000000185510
AUTHOR
Jérôme Brunet
Growth mode and self-organization of LuPc2on Si(001)-2×1vicinal surfaces: An optical investigation
We report an investigation of the initial growth and of the self-organization of lutetium biphthalocyanine LuPc2 on Si(001)-2 x 1 vicinal surfaces. Using surface-sensitive optical spectroscopies, namely, surface-difference-reflectance spectroscopy (SDRS) and reflectance-anisotropy spectroscopy (RAS), together with local-probe microscopies, we are able to propose a scenario for the growth mode up to about 20 nm. We demonstrate that the growth mode initially proceeds through the formation of a wetting layer, followed by the formation of clusters whose sizes increase while keeping a constant shape in which the molecules are inclined. Moreover, the LuPc2 molecules are self-organized along the s…
Selectivity improvement of semi-conducting gas sensors by selective filter for atmospheric pollutants detection
International audience; The monitoring of atmospheric pollution using chemical gas sensors is a challenge due to the lack of selectivity of most existing devices. However, their performances can be improved using filtering films achieving the separation or the removal of some gases. This study is focused on the detection of carbon monoxide and of oxidant pollutants (nitrogen dioxide and ozone) by sensors constituted of SnO2, or phthalocyanine compounds. Two types of filters were investigated. Filters based on MnO2 powder are successful to remove ozone while preserving nitrogen dioxide in a large temperature range from ambient to 400 -C, but they partially convert carbon monoxide. The second…
All-organic device with integrated chemical filter dedicated to the selective measurement of NO2 in air
Abstract An original organic semiconductor gas sensor devoted to the selective monitoring of nitrogen dioxide in air has been successfully developed. This device combines the great sensitivity and the partial selectivity toward oxidizing gases of a molecular organic semiconductor, copper phthalocyanine, with the O3 filtering selectivity of an organic material, indigo. Experimental measurements highlight filtering yield of indigo close to 100% toward O3 and lower than 10% for NO2. Nanometric indigo layers were realized for the first time by thermal evaporation and characterized by FT-IR spectroscopy. Such all-organic device exhibits a high NO2 sensitivity for low concentrations, a resolution…
Microwave-based gas sensor with phthalocyanine film at room temperature
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…
Molecular semiconductor-doped insulator (MSDI) heterojunctions: an alternative transducer for gas chemosensing
New organic devices including a heterojunction between a semiconducting molecular material (MS)--lutetium bisphthalocyanine (LuPc2)--and a doped insulator (DI)--copper phthalocyanine (Cu(F(n)Pc), where n = 0, 8, 16)--are designed and studied as transducers for redox-active species sensing.
Development of gas sensors by microwave transduction with phthalocyanine film
International audience; This work presents a new transduction mode for gas sensing using a passive microwave circuit at room temperature. The design of the sensor includes a microstrip line where is deposited a thin molecular layer of cobalt phthalocyanine (CoPc). The material is 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 ammonia, the reflected wave is specific to the species concentration. The sensor response is the reflected wave over the incident wave ratio at each frequency traduced by the reflected coefficient. The study deals with the influence of molecular sensitiv…