Recent Progress of Imaging Chemical Bonds by Scanning Probe Microscopy: A Review.

In the past decades, the invention of scanning probe microscopy (SPM) as the versatile surface-based characterization of organic molecules has triggered significant interest throughout multidisciplinary fields. In particular, the bond-resolved imaging acquired by SPM techniques has extended its fundamental function of not only unraveling the chemical structure but also allowing us to resolve the structure-property relationship. Here, we present a systematical review on the history of chemical bonds imaged by means of noncontact atomic force microscopy (nc-AFM) and bond-resolved scanning tunneling microscopy (BR-STM) techniques.