Projects – University of Copenhagen

Projects

In the Nano Chemistry Group, our research targets the design, synthesis and properties of novel graphene, metallic, organic and f-block containing materials for: molecular electronics, molecular self-assembly, fluorescent probes, and optical sensors. We published our work in both leading general journals: Nature Chemistry, JACS, Chemical Sciences, Chem. Comm., and more specialized journals: ACS Nano, Langmuir, and Advanced Materials.

Our projects are highly interdisciplinary and involve collaboration with physicists, chemists, engineers, biologist as well as medical researchers locally in the NSC, in industry and at academic institutions across the globe. On the following two pages, you will find some examples of recent and on-going research in our group.

Fluorescent Dyes

Luminescent molecules play a vital role in medical and biological research due to their ability to sense, track and visualize DNA, proteins and other important biomolecules. The development of new, functional and more sensitive sensor molecules is a key activity in the Nano Chemistry Group.

We have recently made two breakthroughs using our luminescent molecules. We were the first to demonstrate the use of near-infrared emission of lanthanide complexes to visualize objects in a confocal microscope (Chem Comm 2015). And we were the first to demonstrate intensity ratiometric sensing of oxygen, by using a molecular system with internal calibration (Chem Sci 2015).

Detailed experimental and theoretical studies of the fundamental photophysical properties of pH sensitive rhodamine dyes have lead us to suggest a new model explaining the function of these important fluorescent indicators (Chem Eur J 2015).

Self-assembly of cationic pi-systems

When organic dyes are packed closely together, their optical properties are strongly depending on the exact structure. In some cases, such materials may act as antennas guiding light energy from large areas to specific molecules or guests in the system, similarly to what happens in the natural photosynthetic machinery. We design and synthesize new dyes with the ability to self-assemble into well-defined nanostructures (e.g. thin films, micelles or nanotubes) and study the relationship between the nanostructure and energy transport.

Ultra-thin and flexible electrodes for molecular electronics

The ultimate goal of molecular electronic research is to make nanoscale electronic components, where molecules play the role of transistors, memory bits and rectifiers. A major challenge in the field is how to create reliable electronic contact to the molecules. When metal contacts are used, short-circuits or damage to the fragile molecular active layer occur frequently. We have developed a method for fabricating and placing a few-nanometer thick layer of a flexible and highly conducting graphene film on top of a single layer of molecules. The thin graphene film protects the molecules and prevent short-circuits from forming. In this way, a new type of molecular device with the soft graphene electrodes have been developed (Advanced Materials 2012, 24, 1333–1339). We have further demonstrated how the optical transparency of the graphene film allows light to reach the active molecules in the nanodevice. By incorporating a light switchable molecule we were able to modulate the electrical conductance by light (Advanced Materials 2013, 25, 4164–4170.). Using the same nanoelectronic device structure, we have recently made bias switchable junctions of organic polymers (Nature Comm. 2015)

We have been investigated a new anchoring group for molecular electronics, based on a triazatriangulene (TATA) platform system. We demonstrated that despite the presence of a sp3 hybridized carbon atom in the conduction path, the TATA platform displays a contact resistance only slightly larger than commonly used thiols (Langmuir 2014).

Graphene technology

In collaboration with researchers from the Technical University of Denmark (DTU) and AU, the Nano Chemistry Group is partner in two large research projects with several industry partners on the use of graphene materials for industrial coatings and printed electronics. The projects have a total budget of DKK 65m(EUR 9m).

Carbonhagen

Since 2010, we have organized an annual international symposium on research and applications of carbon nanomaterials in collaboration with DTU Nanotech.