New n-type molecular semiconductor–doped insulator (MSDI) heterojunctions combining a triphenodioxazine (TPDO) and the lutetium bisphthalocyanine (LuPc2) for ammonia sensing

Abstract

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

Modulation of the organic heterojunction behavior, from electrografting to enhanced sensing properties

“…DMBz is the best MSDI developed in the laboratory. [16,26] Its sensitivity was of the same order of magnitude as the polymer-based devices [27][28][29][30][31] but lower than devices made from graphene [32] for which desorption is obtained by heating at ca. 200°C, or from hybrid materials, e.g.…”

Electrochemical and Spectroelectrochemical Behavior of a Tetracyanotriphenodioxazine in Solution and Thin‐Films

“…Figure depicts the absorption spectrum of a film of vacuum evaporated TiPS‐TPDO‐tetraCN deposited on an ITO electrode. Compared to that of TiPS‐TPDO‐tetraCN in solution (Figure and Table ) or to that of a film deposed by spin coating, additional bands appeared at 460, 585 and 638 nm which have been attributed to the diprotonated compound (TiPS‐TPDO‐tetraCN)H 2 . The reduced form is certainly stabilized in the solid‐state via π‐π interactions.…”

“…The only difference is the position of the shoulder at 574 nm that is slightly shifted to 564 nm in presence of water. It should be noted that the UV‐visible spectrum at the end of the electrolysis remained the same as without water and still was different from that of the diprotonated compound (TiPS‐TPDO‐tetraCN)H 2 . It corresponded only to that of the dianionic compound (Figure and Table ).…”

“…We previously demonstrated that films obtained by vacuum evaporated TiPS‐TPDO‐tetraCN lead to the formation of the diprotonated molecule. Figure depicts the absorption spectrum of a film of vacuum evaporated TiPS‐TPDO‐tetraCN deposited on an ITO electrode.…”

“…Recently, we extended their potentialities of n‐type OSCs to another organic electronic device – the conductometric chemical sensors . Thus, we reported a new class of n‐type sublayer in Molecular Semiconductor – Doped Insulator heterojunctions (MSDI) made of a tetracyano triphenodioxazine bearing two triisopropylsilylethynyl moieties (TiPS‐TPDO‐tetraCN), combined with a highly conductive molecular material, the lutetium bisphthalocyanine, LuPc 2 . In the course of this investigation, an unexpected behavior was highlighted.…”