Directed on-surface growth of covalently-bonded molecular nanostructures

Starting from a clean, ordered surface, the growth of new materials can be accomplished with atomic precision at a monolayer thickness through the controlled coupling of molecules. In this article, we provide an overview of the use of on-surface reactions for the formation of oligomer and polymer products from organic molecular precursors. This approach can facilitate the growth of novel materials: Flat, nanoscale architectures with controlled chemistry, topology and functionality. Our aim is to create a picture of the progress and challenges in this emerging field, with a focus on the mechanisms available for guiding the shape and size of the products.