Unravelling electronic dynamics in supramolecular semiconductors from femtoseconds to milliseconds

在超分子电子学中，复杂的结构是用分子的“砖”建造的，这些结构被设计成具有电子性质，可以在电子应用中用作有源元件。例如，它们支持电流的方式与硅大致相同，硅是一种成熟的半导体材料。这使得用本质上是塑料的材料制造显示器、太阳能电池和其他电子设备成为可能。这些材料在科学界引起了相当大的兴奋。这些所谓的有机半导体的有用应用依赖于分子之间可控的相互作用，并受益于明确定义的分子间结构。例如，当分子采用有序构象，分子相互作用在平行于传输方向的方向上时，电荷传输的效率就会提高。我们的目标是实时测量在这些纳米结构的电子应用中非常重要的过程。我们将通过使用短激光脉冲(短于百万分之一秒)来启动电子事件，并通过绘制启动激光脉冲后另一个激光脉冲的光发射或吸收图来跟踪这些过程的时间演变。了解这些新的和令人兴奋的材料中的电子过程对于有机电子的进一步发展至关重要，而不仅仅是材料和设备参数的增量优化。然而，从这个计划中获得的理解将对其他科学领域产生深远的影响。例如，我们将与光合作用中的光收集和DNA中的能量传输进行比较。此外，这项研究是及时的，因为最近发展的模型材料明确地将结构与电子动力学联系起来。这项工作利用化学家和物理学家的协同努力来设计用于电子应用的新材料。

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.