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International audienceBased on the electrochemical properties of a series of metallophthalocyanines this article shows that the phthalocyanine bearing four alkoxy groups and twelve fluorine atoms behaves approximately as those with eight fluorine atoms. This indicates that the electron-donating effect of one alkoxy group balances the electro-withdrawing effect of one fluorine atom. We engaged three metallophthalocyanines, namely the octafluoro copper phthalocyanine, Cu(F8Pc), an octaester metallophthalocyanine and a phthalocyanine bearing four alkoxy groups and twelve fluorine atoms, Zn(T4F12Pc), in building original conductometric transducers that are Molecular Semiconductor – Doped Insulator heterojunctions (MSDIs) in association with the highly conductive lutetium bisphthalocyanine, LuPc2. Whereas the octaester derivative and Zn(T4F12Pc) exhibited a negative response to ammonia, as expected for p-type materials, Cu(F8Pc) exhibited a particular behavior. At low humidity levels, 30 and 10% rh, the current of the Cu(F8Pc)/LuPc2 MSDI decreases, similarly to p-type devices, but at higher relative humidity values, 70% rh, the current increases under ammonia, which is the signature of a n-type behavior. This ambipolar behavior is unique amongst semiconducting sensing materials. This work opens the way to the study of ambipolar materials as sensing materials for the development of a new type of conductometric gas sensors

International audienceMolecular semiconductor-doped insulator (MSDI) heterojunctions were designed using a new family of sublayers, namely triphenodioxazines (TPDO). The device obtained by combining the tetracyano triphenodioxazine bearing two triisopropylsilylethynyl moieties as a sublayer with the lutetium bisphthalocyanine (LuPc2) as a top layer showed a nonlinear current-voltage characteristic independent of the sign of the polarization, which is the signature of MSDI heterojunctions. Thus, a TPDO was used in a chemical sensor for the first time. Despite LuPc2 being the only material exposed to the atmosphere, the positive response of the device under ammonia revealed the key role played by the n-type TPDO sublayer. The device exhibits a response stable over time and can operate in a broad range of relative humidity. (C) 2017 Elsevier B.V. All rights reserved