Revisiting the electronic properties of Molecular Semiconductor – Doped Insulator (MSDI) heterojunctions through impedance and chemosensing studies

Abstract The core activity of this work was to give a new interpretation of the electronic behavior of Molecular Semiconductor – Doped Insulator heterojunctions (MSDI), a new organic device combining two molecular materials with very different electronic properties. We focused on understanding the phenomenon occurring at the interface of fluorinated and non-fluorinated phthalocyanines that appears to be a determining factor for the electronic charge transport in the two-component thin film and ultimately deciding the nature of gas sensing, as illustrated with ozone and ammonia chosen as examples of accepting and donating gases. The impedance measurements showed that the Schottky contact between the sublayer and the electrodes also plays a key role. They, furthermore, provide complementary data for the selective detection of ammonia and relative humidity in air.