High-sensitive room-temperature NO2 sensor based on a soluble n-type phthalocyanine semiconductor

2(3),9(10),1 6 (17),23(24)-tetrakis(2,2,2-trffiuoroethoxy) phthalocyanine H2Pc(OCH2CF3)(4)(1) has been synthesized characterized by using MALDI-TOF MS, H-1 NMR, UV-vis spectra and differential pulse voltammetry. Our work addresses this by introducing four electron-withdrawing trifluoroethoxy substituents at the periphery of the phthalocyanine ring to ensure the sufficient solubility and suitable LUMO energy level and thus successfully realize soluble n-type organic semiconductor. Furthermore, H2Pc(OCH2CF3)(4) exhibited the high crystallinity and large specific surface area as well as good conductivity in the thin solid film fabricated by a simple solution-based quasi-Langmuir-Shafer (QLS) method. Importantly, the highly sensitive, stable and reproducible responses to electron-accepting gas NO2 in 100-500 ppb range are observed for the QLS film of 1 at room temperature, implying the excellent potential of 1 as the NO2 sensor for applications in practical environments. In addition, the response of the QLS film of 1 is linearly correlated to the NO2 concentration. The interaction between the H2Pc(OCH2CF3)(4) film and NO2 molecules with different concentrations was found to follow first-order kinetics. The present result represents not only the first example of n-type phthalocyanine-based NO2 sensor obtained by a solution-based method, but more importantly provides a new strategy for the molecular design to obtain soluble n-channel organic semiconductors in the field of sensing device fabrication. (C) 2017 Published by Elsevier B.V.