Imaging Charge Distribution Within Molecules by Scanning Probe Microscopy

Charge distribution on surfaces and molecules plays an important role in many physical and chemical processes including catalytic reactions, adsorption, adhesion and charge transport. However, detailed mapping of the spatial charge distribution on atomic scale still remains a challenge, despite recent advances in the field of scanning probe microscopy. Consequently, we are witnessing extensive activity in search for a reliable and robust protocol to image the charge distribution. In this chapter, we will discuss different methods which provide information about charge distribution at atomic or submolecular scale, including Kelvin probe force microscopy, scanning quantum dot microscopy or high-resolution imaging with functionalized tips. We will briefly discuss the mechanism of each of the different methods as well as their advantages and drawbacks. Finally, we will provide a brief outlook and perspectives for further improvement of charge distribution mapping on the submolecular level.