PHOTORESPONSIVE COMPONENTS FOR USE AS VARIABLE RESISTORS FOR APPLICATIONS IN MOLECULAR-SCALE ELECTRONICS

分子电子学是一个跨越物理、化学和材料科学的新兴跨学科领域，有望将摩尔定律扩展到传统硅基电路的预期极限之外。该领域的一个主要主题是设计和制造能够复制宏观电子元件基本特征的简单分子，包括无源（例如，导线）和有源（例如，电容器）。在这里，我们建议将光响应开关集成到分子级电路中，这样开关就可以通过激光脉冲照射打开。与普通开关一样，一旦打开，电子特性将发生巨大变化，这种情况将在几个逻辑电路中进行测试。虽然开关的打开非常快，随后的关闭将是缓慢的，可以实时跟踪。这种情况将允许在关闭期间监控电子属性。其工作原理包括围绕碳-碳键的受限旋转，开关将适应于稳定在可见光照射下形成的电荷分离状态。因此，当供体吸收光子时，供体-桥-受体分子中的桥将被优化为快速通过键的电子转移。第二个脉冲，以不同的频率发出，将打开开关并将电桥转换为不良导体。由于不利的构象，电荷重组将是缓慢的，并且电荷分离状态将可用于化学应用。

Molecular electronics, an emerging interdisciplinary field spanning physics, chemistry, and materials science, holds promise for extending Moore's law beyond the anticipated limits of conventional silicon-based electrical circuits. A major theme within the field concerns the design and fabrication of simple molecules able to duplicate the essential features of macroscopic electronic components, both passive (e.g., conducting wires) and active (e.g., capacitors). Here, we propose to integrate a photo-responsive switch into a molecular-scale circuit in such a way that the switch can be opened by illumination with a laser pulse. As with a normal switch, the electronic properties will change dramatically once opened and this situation will be tested in several logical circuits. Whilst opening of the switch is very fast, subsequent closure will be slow and can be followed in real time. This situation will permit the electronic properties to be monitored during closure. The operating principle involves restricted rotation around a carbon-carbon bond and the switch will be adapated to stabilise a charge-separated state formed under visible light illumination. Thus, the bridge in a donor-bridge-acceptor molecule will be optimised for fast through-bond electron transfer when the donor absorbs a photon. A second pulse, delivered at a different frequency, will open the switch and convert the bridge to a poor conductor. Charge recombination will be slow, because of the unfavourable conformation, and the charge-separated state will be available for chemical applications.