Highly ordered sandwich-type (phthalocyaninato)(porphyrinato) europium double-decker nanotubes and room temperature NO2 sensitive properties

Abstract

A sandwich-type (phthalocyaninato)(porphyrinato) europium double-decker complex Eu(TPyP){Pc-(OC₈H₁₇)₈} [TPyP = meso-tetra(4-pyridyl)porphyrin; Pc-(OC₈H₁₇)₈ = 2,3,9,10,16,17,23,24-octakis(octyloxy)phthalocyanine] (2) was designed and prepared. For comparative studies, Eu(TPyP)(Pc) (1) was also prepared. Highly ordered nanotubes of complexes 1 and 2 were successfully fabricated by using an anodized alumina oxide (AAO) template method. The nanotubes were comparatively investigated by electronic absorption spectra, scanning electron microscopy (SEM), low-angle X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDS) techniques. Both nanotubes of complexes 1 and 2 showed good conductivities and presented an efficient gas sensing platform for the ultrasensitive detection of NO₂ at room temperature. In particular, the detection limit and response/recovery times for the proposed sensors based on complex 2 were lower and faster than those of complex 1, indicating the significant effect of a molecular packing mode on tuning the gas sensing performance of organic semiconductors.