Photothermal Cantilever Deflection Spectroscopy. (1st January 2019)

• Record Type: Journal Article
• Authors: Kim, Seonghwan; Thundat, Thomas
• Is Part Of: Electrochemical Society Interface. Volume 28:Number 3(2019)
• Page Start: 55
• Page End: 57
• Publication Date: 2019-01-01
• Subjects: microcantilever -- IR spectroscopy -- chemical sensor -- explosives
• DOI: 10.1149/2.F07193IF
• Languages: English
• ISSNs: 1064-8208

Abstract

Abstract : Chemical sensors based on adsorption-induced deflection of microfabricated cantilevers offer very high sensitivity. Cantilever deflection occurs when molecular adsorption is confined to one side of the cantilever beam. Although these cantilever sensors have very high sensitivity, they do not have any chemical selectivity. Chemical selectivity is obtained by immobilizing chemoselective interfaces or receptors on the cantilever surface, and thus this approach suffers from chemical interferences. This problem of chemical selectivity can be overcome by exploiting the high thermal sensitivity of bi-material microcantilevers. Physisorbed molecules on a bi-material cantilever under resonant excitation by infrared (IR) radiation generate heat during nonradiative de-excitation, which results in cantilever deflection. Monitoring the variations in the cantilever deflection as a function of IR wavelength shows IR absorption peaks of the molecules. This photothermal cantilever deflection spectroscopy has very high sensitivity and selectivity and offers unprecedented opportunities for chemical sensing without chemoselective interfaces or receptor molecules.