Exploring the Potential Use of Metal-Supported Endofullerenes and Exofullerenes as Multistate Switches for Molecular Electronics

探索金属支撑的内富勒烯和外富勒烯作为分子电子学多态开关的潜在用途

• 批准号: 2449083
• 金额: --
• 依托单位: University of St Andrews
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2449083
• 关键词: Exploring; Potential; Use; Metal; Supported

Silicon is the base material for current electronic components such as transistors and switches. With progress in solution processing techniques for electronics integration (e.g. nanolithography), every year is accompanied with a reduction in size of individual components. Moore's law predicts that the electronic components will soon reach scaling limits in the miniaturization process. Hence, research into alternatives to silicon-based components is vital to sustain our ability to devise better performing and cost-effective electronic devices that afford greater flexibility and reduced energy consumption.The field of molecular electronics aims at advancing the miniaturization of electronic devices, by exploiting single molecules to perform the function of individual components [1]. A molecular switch is defined as a molecule that displays stability in two or more states (e.g. "on" and "off" involving conductance, conformation etc.) and upon application of a controlled external perturbation, electric or otherwise, undergoes a reversible change such that the molecule is altered. Previous work has shown multi-state molecular switches with up to four and six distinct states [2,3]. Our research group in St Andrews has recently reported on a multi-state single molecule switch using the endohedral fullerene Li@C60 that displays 14 molecular states which can be statistically accessed [4]. This was achieved using low temperature scanning tunnelling microscopy and spectroscopy. In this thesis, we propose to further explore the use of metal-supported fullerenes as multistate switches for molecular electronics. Amongst the topics we want to address: (1) The exact excitation mechanism operating in Li@C60 multi-switching is unknown. We believe that it relies on resonant tunnelling via the superatom molecular orbitals of the fullerene cage as a means of Li activation [4]. We will explore strategies to prove this or otherwise. (2) Do other endofullerene species display multi-state switching? (3) Exofullerenes adsorbed on adequate supports have been poorly investigated to date. We will study, by means of STM, a few selected systems synthesized by our organic chemistry collaborators. (4) Can photons (UV and near-VIS) be used as excitation source to induce Li switching in Li@C60? We will couple our STM setup with a UV source to investigate the potential use of exofullerenes towards novel nano-opto-electronic devices.The present thesis work is part of a multidisciplinary collaboration involving theoretical and experimental studies related to the development of multistate molecular switches based on endohedral fullerenes. Our collaborators are: (1) Prof. Eleanor Campbell (Edinburgh) for gas-phase spectroscopy measurements, (2) Dr Andreas Stasch (St Andrews) for the organic synthesis of selected exofullerenes, and (3) Dr Amy Khoo (A*STAR Singapore) for high-level DFT-based calculations. [1] Aviram, A.; Ratner, M. A. Chemical Physics Letters 1974, 29, 277-283.[2] Auwaarter, W.; Seufert, K.; Bischoff, F.; Ecija, D.; Vijayaraghavan, S.; Joshi, S.; Klappenberger, F.; Samudrala, N.; Barth, J. V. Nature Nanotechnology 2012, 7, 41-46.[3] Huang, T.; Zhao, J.; Feng, M.; Popov, A.A.; Yang, S.; Dunsch, L.; Petek, H. Nano Letters 2011, 11, 5327-5332.[4] Chandler, H.J.; Stefanou, M.; Campbell, E.E.B.; Schaub, R. Nature Communications 2019, 10, 2283.

硅是当前电子元件（如晶体管和开关）的基础材料。随着用于电子集成（例如纳米光刻）的溶液处理技术的进步，每年都伴随着单个组件尺寸的减小。摩尔定律预测，在小型化过程中，电子元件将很快达到尺寸极限。因此，研究硅基元件的替代品对于维持我们设计性能更好和成本效益更高的电子设备的能力至关重要，这些电子设备提供更大的灵活性和更低的能耗。分子电子学领域旨在通过利用单个分子来执行单个组件的功能来推进电子设备的小型化[1]。分子开关被定义为在两种或更多种状态下显示稳定性的分子（例如，涉及电导、构象等的“开”和“关”）。并且在施加受控的外部扰动（电的或其它的）时，经历可逆的变化，使得分子被改变。之前的工作已经显示了具有多达四个和六个不同状态的多态分子开关[2，3]。我们在圣安德鲁斯的研究小组最近报道了一种使用内嵌富勒烯Li@C60的多状态单分子开关，它显示了14种可以统计访问的分子状态[4]。这是使用低温扫描隧道显微镜和光谱学实现的。在这篇论文中，我们将进一步探索金属支撑富勒烯作为分子电子学的多态开关。在我们想要解决的主题中：（1）在Li@C60多开关中操作的确切激发机制是未知的。我们认为它依赖于通过富勒烯笼的超原子分子轨道的共振隧穿作为Li激活的手段[4]。我们将探索策略来证明这一点或以其他方式。(2)其他富勒烯物种显示多状态开关？(3)迄今为止，对吸附在适当载体上的外富勒烯的研究很少。我们将研究，通过STM，我们的有机化学合作者合成的几个选定的系统。(4)光子（UV和近可见光）可以用作激发源来诱导Li@C60中的Li开关吗？我们将耦合我们的STM设置与紫外光源，以探讨对新型nano-opto-electronicdevices的exofullerenes的潜在用途。本论文工作是一个多学科合作的一部分，涉及理论和实验研究的多状态分子开关的发展为基础的内嵌富勒烯。我们的合作伙伴是：（1）Eleanor坎贝尔教授（爱丁堡）负责气相光谱测量;（2）Andreas Stasch博士（圣安德鲁斯）负责选定外富勒烯的有机合成;（3）Amy Khoo博士（A* 星星新加坡）负责基于DFT的高级计算。[1]Aviram，A.; Ratner，M. A.化学物理快报1974年，29，277-283。[2]Auwaarter，W.; Seufert，K.; Bischoff，F.;埃奇亚，D.; Vijayaraghavan，S.; Joshi，S.; Klappenberger，F.; Samudrala，N.; Barth，J.V. Nature Nanotechnology 2012，7，41-46. [3]黄，T.;赵，J.;冯，M.; Popov，A.A.; Yang，S.; Dunsch，L.; Petek，H. Nano Letters 2011，11，5327-5332. [4]钱德勒，H. J.; Stefanou，M.;坎贝尔，E.E.B.;绍布河《自然通讯》2019，10，2283。