Hybrid optical-electrochemical electronic nose system based on Zn-porphyrin and multi-walled carbon nanotube composite

Abstract

In this work, we have enhanced the capability of an e-nose system based on combined optical and electrochemical transduction within a single gas sensor array. The optical part of this e-nose is based on detection of the absorption changes of light emitted from eight light emitting diodes (LEDs) as measured by a CMOS photo-detector. The electrochemical part works by measuring the change in electrical resistivity of the sensing materials upon contact with the sample vapor. Zinc5,10,15,20-tetra-phenyl-21H,23H-porphyrin (ZnTPP) and multi-walled carbon nanotube (MWCNT) composite was used as the sensing materials based on its good optoelectronic properties. This sensing layer was characterized by UV-Vis spectroscopy and atomic force microscope and tested with various V OC vapors. Density functional theory (DFT) calculations were performed to investigate the electronic properties and interaction energies between ZnTPP and analyte molecules. It can be clearly seen that this hybrid optical- electrochemical electronic nose system can classify the vapor of different volatile organic compounds. © 2012 American Scientific Publishers.