Ambipolar chemical sensors based on the self-assembled film of an amphiphilic (phthalocyaninato) (porphyrinato) europium complex

An amphiphilic mixed (phthalocyaninato) (porphyrinato) europium triple-decker complex Eu-2(Pc)(2)(TPyP) has been synthesized and characterized. Introducing electron-withdrawing pyridyl substituents onto the meso-position of porphyrin ring in the triple-decker to ensure the sufficient hydrophilicity and suitable HOMO and LUMO energy levels and thus successfully realize amphiphilic ambipolar organic semiconductor. Importantly, high sensitive, reproducible p-type and n-type responses towards NH3 and NO2 respectively, based on the self-assembled film of the Eu-2(Pc)(2)(TPyP) fabricated by a simple solution-based Quasi-Langmuir-Shafer (QLS) method, have been first revealed. The good conductivity and crystallinity for the QLS film of Eu-2(Pc)(2)(TPyP) render it excellent sensing property for both electron-donating gas NH3 in 5-30 ppm range and electron-accepting gas NO2 in 400-900 ppb range due to the optimized molecular packing in the uniform-sized nanoparticles depending on the effective intermolecular interaction between the triple-decker molecules, among the best results of phthalocyanine-based chemical sensors for room-temperature detection of NH3 and NO2, respectively. Furthermore, the responses of the QLS film are all linearly correlated to both NH3 and NO2 with excellent sensitivity of 0.04% ppm(-1) and 31.9% ppm(-1), respectively, indicating the great potential of semiconducting tetrapyrrole rare earth triple-decker compounds in the field of chemical sensors. (C) 2017 Elsevier B.V. All rights reserved.