Unravelling electronic dynamics in supramolecular semiconductors from femtoseconds to milliseconds

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In supramolecular electronics, complex architectures are built with molecular 'bricks', and these structures are designed to have electronic properties that can be used as active components in electronic applications. For example, they may support electrical current in much the same way as silicon, a well-established semiconductor material. This enables fabrication of displays, solar cells, and other electronic devices with materials that are essentially plastics. These materials have caused considerable excitement in the scientific community. Useful applications of these so-called organic semiconductors depend upon the controlled interactions between molecules, and benefit from well-defined intermolecular structure. For example, the efficiency of charge transport is enhanced when molecules adopt ordered conformations with molecular interactions in a direction parallel to the transport direction. Our objectives are to measure, in real time, processes that are important in electronic applications of these nanostructures. We will do so by starting electronic events with short laser pulses (shorter than a millionth of a millionth of a second) and following the time evolution of those processes by mapping light emission or absorption of another laser pulse after the initiating laser burst. Understanding electronic processes in these new and exciting materials is essential for further development of organic electronics beyond incremental optimisation of materials and device parameters. However, the understanding obtained from this programme will have profound implications for other areas of science. For example, we will develop comparisons with light harvesting in photosynthesis and energy transport in DNA. Furthermore, this research is timely because of recent development of model materials to correlate unambiguously structure with electronic dynamics. This work takes advantage of the synergistic efforts of chemists and physicists to design new materials for electronic applications.