Collaborative Research: Tuning Graphene Nanoribbon Properties with Non-hexagonal Rings

合作研究：用非六角环调节石墨烯纳米带性能

• 批准号: 2204252
• 负责人: Michael Crommie
• 金额: $ 30万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-08-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2204252&HistoricalAwards=false
• 关键词: Collaborative; Research; Tuning; Graphene; Nanoribbon

With support from the Macromolecular, Supramolecular, and Nanochemistry (MSN) Program of the Division of Chemistry, Professors Michael F. Crommie of the University of California at Berkeley and Colin Nuckolls of Columbia University are developing methods for the fabrication and characterization of new molecular structures that have the potential to enable faster, smaller, and more energy efficient electronic devices. Current high technology applications involve taking relatively large semiconductor crystals and embedding them with impurities as well as laboriously cutting them into very small shapes to control how they respond to electrical signals. In contrast, this collaborative research team will develop synthetic methods to create molecular analogs of wires and sheets having shapes and sizes that naturally facilitate the flow of electrons and enable their use as functional components in electronic devices. If successful, the new molecular materials that result from this project could eventually provide a cheaper, cleaner, and easier-to-mass-produce alternative to bulk semiconductors, and could also provide smaller and more efficient electrical devices (such as transistors, diodes, and solar cells) than is currently possible. During the course of conducting this project, students and postdoctoral researchers will gain valuable experience in the synthesis and characterization of new nanomaterials using cutting edge instrumental techniques. Several outreach activities targeting K12 students, underrepresented minorities, and the general public are planned. These include hosting laboratory open-house days, nanoscience poster sessions, and nanotechnology workshops; developing TikTok videos that highlight the blend of chemistry and physics that underpins the proposed research; and participating in several community-service programs, such as the Transfer to Excellence (TTE) REU, the Bay Area Scientists Inspiring Students (BASIS), and the Summer Math and Science Honors Academy (SMASH). The main goal of this project is to explore new graphene nanoribbon (GNR)-based systems whose electronic and magnetic properties can be tuned by embedding non-hexagonal carbon rings into the GNR backbone. Chemical synthesis and atomic-scale characterization will be combined to evaluate the utility of this new technique for controlling the electronic properties of bottom-up-fabricated GNRs. Chemical synthesis will be performed to develop new molecular precursors and polymers that enable the growth of GNRs with engineered ring structures on clean metal substrates via surface self-assembly and matrix-assisted-deposition (MAD). GNR local electronic and magnetic properties will be characterized using scanning tunneling microscopy (STM) and will be compared to theoretical predictions. Fundamental questions will be addressed such as the degree to which GNR radical states can be controlled by inserting simple non-hexagonal ring structures into molecular precursor building blocks. Competition between hybridization of adjacent radical states and on-site Coulomb repulsion within GNRs will be tuned with the aim of controlling GNR magnetic order, something never before accomplished. Other fundamental properties of new GNR systems will be evaluated, such as energy gaps, wavefunction distributions, electron hopping amplitudes, and spin-spin interaction strengths. If successful, this work could help build a foundation for the use of bottom-up fabricated GNRs as a new nanoelectronics platform. This could be transformative since GNRs have excellent electronic properties and can be synthesized in bulk quantities with high-fidelity and atomic precision from molecular starting materials. This could, in principle, allow quantum device densities much higher than other material platforms at very low cost, opening new possibilities for quantum device applications that would be beneficial to society.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.

在化学系的大分子，超分子和纳米化学（MSN）计划的支持下，加州大学伯克利分校的迈克尔·F·克罗米（Michael F. 当前的高科技应用涉及采用相对较大的半导体晶体，并将它们嵌入杂质以及费力地将它们切成很小的形状，以控制它们对电信号的反应。 相比之下，该协作研究团队将开发合成方法，以创建具有形状和尺寸的电线和薄板的分子类似物，它们自然促进电子流，并使它们可以用作电子设备中的功能组件。 如果成功的话，该项目产生的新分子材料最终可能会提供更便宜，更清洁且易于质量的材料，以替代散装半导体，并且还可以提供比目前可能的较小，更有效的电气设备（例如晶体管，二极管和太阳能电池）。 在进行该项目的过程中，学生和博士后研究人员将使用尖端工具技术在新纳米材料的合成和表征方面获得宝贵的经验。 计划针对K12学生，代表性不足的少数民族和公众的几项外展活动。 其中包括举办实验室开放日，纳米科学海报会议和纳米技术讲习班；开发Tiktok视频，这些视频强调了拟议研究的化学和物理学的融合；并参加了几个社区服务计划，例如转移到卓越（TTE）REU，湾区科学家启发学生（基础）和夏季数学和科学荣誉学院（Smash）。 该项目的主要目的是探索基于新的石墨烯纳米替烯（GNR）的系统，其电子和磁性可以通过将非甲状腺碳环嵌入GNR主链中来调整。化学合成和原子尺度表征将合并，以评估这种新技术控制自下而上制作的GNR的电子特性的实用性。化学合成将进行开发新的分子前体和聚合物，从而通过表面自组装和基质辅助沉积（MAD）在清洁金属底物上使用工程环结构的GNR生长。 GNR局部电子和磁性特性将使用扫描隧道显微镜（STM）进行表征，并将与理论预测进行比较。将解决基本问题，例如可以通过将简单的非甲状腺环结构插入分子前体构建块来控制GNR激进状态的程度。将调整GNR中相邻自由基状态与现场库仑排斥的杂交之间的竞争，以控制GNR磁性，这是前所未有的。还将评估新的GNR系统的其他基本特性，例如能隙，波函数分布，电子跳振幅和自旋旋转相互作用强度。如果成功，这项工作将有助于建立基础，以将自下而上的制造GNR用作新的纳米电子平台。 由于GNR具有出色的电子特性，并且可以从分子起始材料中以高保真和原子精度合成。原则上，这可以使量子设备密度比其他物料平台以非常低的成本高得多，这为量子设备应用开辟了新的可能性，这将有利于社会。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子优点和更广泛影响的审查标准来通过评估来获得支持的。

项目成果

Imaging Field‐Driven Melting of a Molecular Solid at the Atomic Scale

成像场——原子尺度上分子固体的驱动熔化

• DOI: 10.1002/adma.202300542
• 发表时间: 2023
• 期刊: Advanced Materials
• 影响因子: 29.4
• 作者: Liou, Franklin;Tsai, Hsin‐Zon;Goodwin, Zachary A.;Aikawa, Andrew S.;Ha, Ethan;Hu, Michael;Yang, Yiming;Watanabe, Kenji;Taniguchi, Takashi;Zettl, Alex
• 通讯作者: Zettl, Alex