A guide to nanoscale IR spectroscopy: resonance enhanced transduction in contact and tapping mode AFM-IR

Abstract

Infrared (IR) spectroscopy is a broadly applicable, composition sensitive analytical technique. By leveraging the high spatial resolution of atomic force microscopy (AFM), the photothermal effect, and wavelength-tunable lasers, AFM-IR enables IR spectroscopy and imaging with nanoscale (< 10 nm) resolution. The transduction of a sample's photothermal expansion by an AFM probe tip ensures the proportionality between the AFM-IR signal and the sample absorption coefficient, producing images and spectra that are comparable to far-field IR databases and easily interpreted. This convergence of characteristics has spurred robust research efforts to extend AFM-IR capabilities and, in parallel, has enabled AFM-IR to impact numerous fields. In this tutorial review, we present the latest technical breakthroughs in AFM-IR spectroscopy and imaging and discuss its working principles, distinctive characteristics, and best practices for different AFM-IR measurement paradigms. Central to this review, appealing to both expert practitioners and novices alike, is the meticulous understanding of AFM-IR signal transduction, which is essential to take full advantage of AFM-IR capabilities. Here, we critically compile key information and discuss instructive experiments detailing AFM-IR signal transduction and provide guidelines linking experimental parameters to the measurement sensitivity, lateral resolution, and probed depth. Additionally, we provide in-depth tutorials on the most employed AFM-IR variants (resonance-enhanced and tapping mode AFM-IR), discussing technical details and representative applications. Finally, we briefly review recently developed AFM-IR modalities (peak force tapping IR and surface sensitivity mode) and provide insights on the next exciting opportunities and prospects for this fast-growing and evolving field.

Graphical abstract: A guide to nanoscale IR spectroscopy: resonance enhanced transduction in contact and tapping mode AFM-IR

Article information

Article type
Tutorial Review
Submitted
03 Feb 2022
First published
26 May 2022
This article is Open Access
Creative Commons BY license

Chem. Soc. Rev., 2022, Advance Article

A guide to nanoscale IR spectroscopy: resonance enhanced transduction in contact and tapping mode AFM-IR

J. J. Schwartz, D. S. Jakob and A. Centrone, Chem. Soc. Rev., 2022, Advance Article , DOI: 10.1039/D2CS00095D

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements