Emission Properties of Single Molecules and Aggregates
- Electronic Properties of Molecules Used for Opto-electronic Devices
- Emission Properties of Single Molecules and Aggregates
- RNA Splicing at the Single Molecule Level
- Optical Properties of Dye-Labeled DNA Gold Nanoparticle Constructs
- Development of Novel Probes for Intra-Cellular Studies
Scheme of a LED
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Instrumentation:
- Single Molecule Fluorescence Microscopy
Recent years has seen a huge growth in the types of molecules that have been designed for molecular electronics such as light emitting diodes (LEDs) and photovoltaic cells. Such molecules have several advantages over conventional inorganic semi-conductors for these applications including the fact that they can be processed from solution to form flexible films and that elements of organic design can be used to tune properties such as brightness, stability, and the wavelengths of emission to produce devices that emit throughout the visible spectrum. One molecule that has seen the most successful applications thus far is MEH-PPV and shorter chain MEH-PPV oligomers. When these molecules are placed in thin films to fabricate devices, they typically form aggregates. Aggregates confer several desirable properties for device function such as protection from oxidative damage and enhanced charge transport. However, they also typically shift the wavelength of emission to lower energies and often significantly reduce its intensity.
Our group is investigating the relationships between molecular structure (i.e. oligomer length and substitution patterns) and the brightness and photo-stability of molecules in the solid state, both in isolation (i.e. as single molecules) and as aggregates. Molecules that retained a high degree of brightness, even under aggregate conditions, would be good candidates to explore for molecular electronic devices. Through a systematic study of the effect of monomer chain length and aggregate size on photostability and brightness we have identified those that exhibit favorable properties in the aggregate form.
