| AVS 64th International Symposium & Exhibition | |
| Thin Films Division | Thursday Sessions |
| Session TF-ThP |
| Session: | Thin Films Poster Session |
| Presenter: | Nicholas Besley, The University of Nottingham, UK |
| Authors: | V.V. Korolkov, The University of Nottingham, UK K. Watanabe, National Institute for Materials Science, Japan T. Taniguchi, National Institute for Materials Science, Japan N.A.S. Besley, The University of Nottingham, UK P.H. Beton, The University of Nottingham, UK |
| Correspondent: | Click to Email |
For a long time the molecular self-assembly has been limited to engineering 2D molecular structures on surfaces. Here we demonstrate a successful approach that extends self-assembly into 3D by creating supramolecular heterostructures1. Essentially, these are layered organic materials that are stabilized by hydrogen bonds in plane and by van der Waals interactions between layers. Supramolecular heterostructures are formed by growing sequential layers of bi- and mono-component two-dimensional supramolecular arrays stabilized by hydrogen bonding. The heterostructures are formed on layered materials, hexagonal boron nitride (hBN) and graphite, by depositing layers of cyanuric acid/melamine (CA.M), 5,10,15,20-tetrakis(4-carboxylphenyl) porphyrin (TCPP), trimesic acid (TMA) and terephthalyc acid (TPhA).
We analyzed this heterostructures with ambient Atomic Force Microscopy that routinely achieve 0.1 nm resolution with conventional silicon probes. We have developed several approaches to characterize them. These include 'through-the-layer' imaging and scratching experiments to reveal the underlying layer structure.
AFM has confirmed that there is a clear epitaxial arrangement between these layers which intrinsically exhibit hexagonal (CA.M) and TMA, square (TCPP), linear (TPhA) symmetry. We demonstrate that heterostructure formation may be used to control the functional properties of supramolecular layers through a shift of the fluorescence peak position and a suppression of quenching for TCPP epitaxial layers.
The work will present outstanding examples of single molecule and submolecular resolution achieved in the ambient on standard atomic force microscopes. It is also possible to identify the registry between molecules in different layers and we include theoretical models which support our structural assignments and the observed shifts of fluorescent peaks.
1 - Korolkov et al. Nature Chemistry, 2017, in press.