Fourier transform infrared nano-spectroscopy: Mechanism and applications

Fourier transform infrared (FTIR) spectroscopy is an important tool for material characterization. However, due to the diffraction limit, conventional infrared spectroscopy cannot be applied to nanoscale material. In the past decade, FTIR nano-spectroscopy (nano-FTIR), combining scanning near-field optical microscopy and FTIR, has made significant progress. It provides scientists a powerful tool to study polymers, 2D-materials, semiconductor devices, and biomaterials at the nanoscale. In this review, we introduce the development and working mechanism of nano-FTIR, and summarize some typical applications in different research fields. The purpose of this review is to allow readers to understand the basic principles of nano-FTIR, its current development status, and the application potential of this technology. Finally, we briefly summarize current challenges faced by this technology and present some research directions that deserve attention in the future.