Preparation of single walled carbon nanotube-pyrene 3D hybrid nanomaterial and its sensor response to ammonia

In this work, the structural features and sensor response toward ammonia of a three dimensional (3D) SWCNTs material covalently functionalised with 1,6-diethynylpyrene were studied. The target SWCNTs hybrid material was prepared by the reaction of azido substituted SWCNTs with 1,6-diethynylpyrene containing double terminal alkyne groups via the azide-alkyne Huisgen cycloaddition (Click) reaction. The structure of the 1,6-diethynylpyrene compound was determined by different spectroscopic methods such as FT-IR, 1H NMR, MALDI-TOF mass and UV-vis, while its SWCNT-Pyrene 3D hybrid material was characterized by FT-IR, Raman, UV-vis spectroscopies and thermogravimetric analysis. The morphology of the hybrid films was investigated by scanning electron microscope (SEM) and transmission electron microscope (TEM). The sensing performance of the SWCNT-Pyrene 3D hybrid material was studied against low-concentrations of NH3 in the range of 0.1-40 ppm by measuring changes in the films' conductivity at different levels of relative humidity. The reversible electrical sensor response toward ammonia was observed both in the case of SWCNT and SWCNT-Pyrene 3D hybrid films, however the response values of SWCNT-Pyrene 3D hybrid film were higher than those of SWCNT.