Atomic-Level Studies of Molecular Self-Assembly on Metallic Surfaces

Shrinking devices to the nanoscale, while still maintaining accurate control on their structure and functionality is one of the major technological challenges our our era. The use of purposely directed self-assembly processes provides a smart alternative to the troublesome manipulation and positioning of nanometer-sized objects piece by piece. Here, we report on a series of recent works where the in-depth study of appropriately chosen model systems addresses the two key points in self-assembly; building blocks selection and control of bonding. We focus in particular on hydrogen bonding because of the stability, precision and yet flexibility of nanostructures based on this interaction. Complementing experimental information with advanced atomistic modeling techniques based on quantum formalisms is a key feature of most investigations. We thus highlight the role of theoretical modeling while we follow the progression in the use of more and more complex molecular building blocks, or "tectons". In particular, we will see that the use of three-dimensional, flexible tectons promises to be a powerful way to achieve highly sophisticated functional nanostructures. However, the increasing complexity of the assembly units used makes it generally more difficult to control the supramolecular organization and predict the assembling mechanisms. This creates a case for developing novel analysis methods and ever more advanced modeling techniques.