Surface-enhanced infrared absorption

Abstract

Infrared spectroscopy is a powerful tool for the detection and identification of molecules. However, its application is limited by the low infrared absorption cross-sections of molecules. Localized surface plasmon resonances in metal and highly-doped semiconductor nanomaterials can produce large localized electromagnetic field enhancements. When molecular vibrations are in resonance with localized surface plasmon resonances, molecular vibrations are able to be largely amplified. The detection of minute amounts of target molecules can be realized in this way. Surface-enhanced infrared absorption (SEIRA) spectroscopy has recently attracted extensive attention owing to its enormous potential in molecular detection in chemistry, biology and medicine. In this review article, the enhancement mechanism and theoretical models of SEIRA are first introduced. The preparation methods and enhancement effects of various infrared-responsive nanomaterials are then discussed. The applications of SEIRA in diverse areas, such as hyperspectral infrared chemical imaging, detection of biomolecules, monitoring of pollutants in the environment, and on-chip gas sensing, are finally summarized.