Piezoresistive SU-8 Cantilever With Fe(III)Porphyrin Coating for CO Sensing

Carbon monoxide detection is required for various healthcare, environmental, and engineering applications. In this paper, 5,10,15,20-tetra (4,5-dimethoxyphenyl)-21H,23H-porphyrin iron(III) chloride (Fe(III)porphyrin) coated on a piezoresistive SU-8 microcantilever has been used as a CO sensor. Rapid detection of CO down to 2 ppm has been observed with aforementioned sensors. Cantilevers without Fe(III)porphyrin have not responded to CO exposure. Fe(III)porphyrin-coated cantilever selectivity toward CO has been analyzed by measuring the sensor response to various gases such as N$_2$, CO $_2$, O$_2$, ethanolamine, N$_2\\!$O, and moisture. The sensor has exhibited a fast response and recovery times and is fully recoverable after repeated exposures.