Michael A. Boles1, Daishun Ling2,3,4, Taeghwan Hyeon2,3 and Dmitri V. Talapin1,5*

All nanomaterials share a common feature of large surface-to-volume ratio, making their surfaces the dominant player in many

physical and chemical processes. Surface ligands — molecules that bind to the surface — are an essential component of nanomaterial

synthesis, processing and application. Understanding the structure and properties of nanoscale interfaces requires

an intricate mix of concepts and techniques borrowed from surface science and coordination chemistry. Our Review elaborates

these connections and discusses the bonding, electronic structure and chemical transformations at nanomaterial surfaces. We

specifically focus on the role of surface ligands in tuning and rationally designing properties of functional nanomaterials. Given

their importance for biomedical (imaging, diagnostics and therapeutics) and optoelectronic (light-emitting devices, transistors,

solar cells) applications, we end with an assessment of application-targeted surface engineering.