Controlling the Synthesis and Placement of Organic Color-Centers with Light

在化学系大分子、超分子和纳米化学（MSN）项目的支持下，马里兰大学帕克分校的王玉煌教授将解决在单壁碳纳米管表面控制有机色中心（也称为量子缺陷）位置的合成挑战。这些原子缺陷可以一次发射一个光子（光的基本粒子），形成一个单光子源；然而，它们通常在固体中随机存在，缺乏实现对原子结构、表面放置和颜色调整控制所需的合成控制。在单壁碳纳米管表面控制有机色中心的位置，将使纳米管能够在室温下发射单个短波红外光子。该项目的成功实现将使创造和调整相同的有机色中心，发射单一波长，用于生物成像，分子传感和量子信息科学的新兴应用。除了让研究生和本科生，特别是来自代表性不足的群体的学生参与前沿研究之外，该项目还将涉及根据项目结果开发引人入胜的纳米科学和技术演示，并在社区外展活动中与其他人分享这些演示。在这个项目中，王教授和他的团队将利用有机化学方法将小官能团共价连接到半导体碳纳米管宿主上，合成模型缺陷色心。当纳米管被激发时，产生的激子（或电子-空穴对）被有机色中心捕获，产生明亮的短波红外单光子，其“颜色”敏感地取决于缺陷部位的原子结构。该团队将使用这种光学指纹来研究如何利用光在纳米管半导体的碳晶格上产生、擦除或校正这些有机色中心。这项工作如果成功，将为实现原子控制和确定这些缺陷色心的位置铺平道路。该团队还将努力推进一种方法，使追踪暗激子和量化缺陷处激子到光子的转换效率成为可能，这对量子光源和理解这些纳米结构的激发态至关重要。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

With support from the Macromolecular, Supramolecular and Nanochemistry (MSN) program in the Division of Chemistry, Professor YuHuang Wang of the University of Maryland College Park will address the synthetic challenge of the controlled placement of organic color-centers, also known as quantum defects, on the surface of single-walled carbon nanotubes. These atomic defects can emit photons—the elementary particles of light—one at a time, creating a source of single photons; however, they typically exist randomly within the solid, lacking the synthetic control required for achieving control over atomic structure, placement on the surface and color tuning. Controlled placement of organic color-centers on the surface of single-walled carbon nanotubes would enable the nanotubes to emit single, short wave infrared photons at room temperature. Success in accomplishing the objective of the project would enable the creation and tuning of identical organic colo- centers emitting single wavelengths for emerging applications in bio-imaging, molecular sensing, and quantum information science. In addition to the involvement of graduate and undergraduate students, particularly from under-represented groups, in cutting-edge research, the project will also involve developing engaging nanoscience and technology demonstrations based on project results and sharing these with others in community outreach events. In this project, Professor Wang and his team will synthesize model defect color-centers by covalently attaching small functional groups to semi-conducting carbon nanotube hosts using organic chemistry. When the nanotube is excited, the resulting excitons—or electron-hole pairs—are harvested by the organic color-center to produce bright shortwave-infrared single photons whose “color” sensitively depends on the atomic configuration of the defect site. The team will use this optical fingerprint to study how these organic color-centers can be generated, erased, or corrected on the carbon lattice of the nanotube semiconductor using light. This work, if successful, will pave the way to attaining atomic control and deterministic placement of these defect color-centers. The team will also work to advance a method to enable tracing of dark excitons and quantification of the exciton-to-photon conversion efficiency at the defect—a property of fundamental importance to quantum light sources and to the understanding of the excited states of these nanostructures.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.