Highly sensitive VOC gas sensor employing deep cooling of SERS film

The potential of surface-enhanced Raman spectroscopy (SERS) as a highly sensitive and selective gas sensor was investigated experimentally. Especially, the relation between the temperature of a SERS film and gas adsorption or signal intensity was observed systemically and quantitatively, from which the enhancement of gas adsorption and signal intensity by up to 40 times was observed with the SERS film temperature of approx. -80 degrees C, which corresponds to theoretical anticipation and leads to detection sensitivity defined by limit of detection in 3 sigma similar to 1ppb in case of benzene gas within 2-min acquisition time. For SERS, Ag nanorod array films functionalized by propanethiol and a spectrometer with a fiber Raman probe and 785-nm pump laser were employed. The target volatile organic compound gas was benzene. The detection sensitivity of the SERS sensor was similar to 1ppm at room temperature within 2-min acquisition time.