Operando Methods

In order to understand their interaction with the gases, two types of sensitive materials are investigated - semiconducting metal oxides (SMOX) and organic materials . In both cases, all investigation techniques are used in sensor operation conditions (operando) meaning that the samples are fabricated in the same way in which the real sensors are (e.g. the polymers are deposited as thick, porous films onto substrates provided with electrodes and references) and are studied in real-life like conditions (between -20°C and 70°C, at normal pressure, in the presence of humidity and of the target gases). Most of the operando experiments are performed in-house; for organic materials they include: DC resistance, AC impedance spectroscopy, work function changes (Kelvin probe), Pulse and cyclic Voltametry (PV and CV). For the evaluation of the witness sensing layers (prepared in the same time with the real sensors but on special substrates) gravimetric measurements (with quartz microbalances- QMB), Fourier Transformed Infrared Absorption Spectroscopy (FTIRAS) and surface profile optical scan are also performed.