Electrically Conductive 2D Metal-Organic Frameworks and Covalent Organic Frameworks Featuring Built-in Alternating pi-Donor/Acceptor Stacks with Efficient Charge Transport Capacity

导电二维金属有机框架和共价有机框架，具有内置交替 pi 供体/受体堆栈，具有高效的电荷传输能力

• 批准号: 2321365
• 负责人: Sourav Saha
• 金额: $ 57.48万
• 依托单位: Clemson University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2321365&HistoricalAwards=false
• 关键词: Electrically; Conductive; 2D; Metal; Organic

NON-TECHNICAL SUMMARYSustaining the rapid advances of modern electronics and clean energy technologies requires continuous innovation and supply of easily accessible smart materials that can transport and store electrical charges in a programmable fashion. Owing to their synthetic accessibility, structural modularity, and functional tunability, metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) hold great potentials to serve as active components of next-generation electronics and energy-storage devices. Electrical conductivity—a product of charge carrier concentration and mobility—however, remains one of the most elusive traits of MOFs and COFs, prompting researchers to devise new design and synthetic strategies to engineer this much desired electronic property in these crystalline framework materials. With support from the Solid State and Materials Chemistry program in the Division of Materials Research and the Established Program to Stimulate Competitive Research (EPSCoR), Prof. Saha and his research group at Clemson University are developing and implementing a new design strategy to promote long-range out-of-plane charge transport in two-dimensional (2D) MOFs and COFs by incorporating cofacially stacked alternating electron-rich (pi-donor) and electron-deficient (pi-acceptor) arrays and then exploiting their efficient through-space charge delocalization capability in these solid-state materials, which are expected to generate promising intrinsic conductivity. This research project is not only producing novel electrically conductive 2D MOFs and COFs with unique structures and compositions, but also creating an innovative design strategy that can simultaneously facilitate in-plane and out-of-plane charge transport in two orthogonal directions through the layered networks and pi-donor/acceptor stacks, respectively, and thus boost the bulk conductivity of these emerging smart materials. This NSF-funded project is also enabling the PI to develop skilled workforce for future innovations by engaging and mentoring graduate, undergraduate, postdoctoral, and high-school students in cutting-edge materials research, inspire underrepresented minorities to pursue higher education in STEM, and raise scientific awareness of the society through various education and outreach activities at local schools, science museums, and public forums. TECHNICAL SUMMARYOwing to their diverse potentials to serve as active components of modern electronics and energy storage devices, electrically conductive metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) have emerged as most coveted and explored functional materials. Yet, electrical conductivity, which is a function of charge carrier concentration and charge mobility, remains one of the most elusive features of these porous crystalline framework materials chiefly because they often lack efficient charge transport pathways. In two-dimensional (2D) MOFs, electronic conduction can occur within the planes through coordination and conjugated pi-bonds and/or across the planes through pi-stacked layers, whereas in 2D COFs, the latter represent the primary transport pathways. The large disparities between in-plane and out-of-plane charge transport in two orthogonal directions often render the conductivity of these materials highly anisotropic (i.e., direction dependent) and dampen their overall bulk conductivity. To address these issues and simultaneously promote both in- and out-of-plane charge transport such that it leads to higher bulk conductivity in 2D MOFs and COFs, in this project supported by NSF's Solid State and Materials Chemistry (SSMC) Program, Prof. Sourav Saha and his research group at Clemson University are pursuing novel design and synthetic strategies where they incorporate built-in alternating pi-donor/acceptor stacks inside 2D layered frameworks that can facilitate out-of-plane charge transport, bringing this typically less efficient pathway on par with through-bond conduction pathways. Understanding how pi-donor/acceptor stacks consisting of different complementary pi-donor and acceptor units embedded in 2D MOFs and COFs affect their out-of-plane charge transport capability and thus the overall bulk conductivity is creating a new design strategy for next-generation electrically conductive MOFs and COFs. This project is also enabling the PI to fulfill his longstanding commitment to develop skilled workforce capable of leading future innovations by guiding diverse group of researchers to execute complex multifaceted research, motivate minority students to pursue higher education in STEMs, and raise a scientifically aware society through various outreach and educational activities in local community.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.

保持现代电子和清洁能源技术的快速发展需要不断创新和提供易于获取的智能材料，这些材料可以以可编程的方式传输和存储电荷。金属有机框架（MOFs）和共价有机框架（COFs）由于其合成可及性、结构模块化和功能可调性，在下一代电子和储能器件中具有很大的潜力。导电性——电荷载流子浓度和迁移率的产物——仍然是mof和COFs最难以捉摸的特性之一，这促使研究人员设计新的设计和合成策略，以在这些晶体框架材料中设计出这种非常理想的电子特性。在材料研究部固态和材料化学项目以及促进竞争性研究的既定项目（EPSCoR）的支持下，Saha教授和他在克莱姆森大学的研究小组正在开发和实施一种新的设计策略，通过结合协面堆叠富电子（pi-供体）和缺电子（pi-受体）交替阵列，然后利用它们在这些固态材料中的有效的穿越空间电荷离域能力，来促进二维（2D） mof和COFs中的远距离面外电荷传输，有望产生有前途的固有电导率。本研究项目不仅生产了具有独特结构和组成的新型导电二维mof和COFs，而且还创造了一种创新的设计策略，可以同时促进平面内和平面外的电荷在两个正交方向上分别通过分层网络和pi-供体/受体堆栈进行传输，从而提高这些新兴智能材料的整体导电性。这个由nsf资助的项目还使PI能够通过参与和指导研究生、本科生、博士后和高中生从事尖端材料研究，为未来的创新培养熟练的劳动力，激励未被充分代表的少数民族接受STEM高等教育，并通过在当地学校、科学博物馆和公共论坛的各种教育和推广活动提高社会的科学意识。导电性金属有机框架（mof）和共价有机框架（COFs）由于其作为现代电子和储能器件的活性元件的各种潜力，已成为最令人垂涎和探索的功能材料。然而，电导率（电荷载流子浓度和电荷迁移率的函数）仍然是这些多孔晶体框架材料最难以捉摸的特征之一，主要是因为它们通常缺乏有效的电荷传输途径。在二维（2D） mof中，电子传导可以通过配位和共轭pi键在平面内和/或通过pi堆叠层在平面上发生，而在二维COFs中，后者代表主要的传输途径。平面内和平面外电荷输运在两个正交方向上的巨大差异往往使这些材料的电导率具有高度的各向异性（即方向依赖），并降低了它们的整体电导率。为了解决这些问题，同时促进面内和面外电荷传输，从而提高二维mof和COFs的体积导电性，在这个由NSF固态和材料化学（SSMC）计划支持的项目中，克莱姆森大学的Sourav Saha教授和他的研究小组正在寻求新的设计和合成策略，他们将内置的交替pi供体/受体堆栈集成在二维分层框架中，可以促进面外电荷传输，使这种通常效率较低的途径与通过键传导途径相当。了解嵌入2D mof和COFs中由不同互补的pi-供体和受体单元组成的pi-供体/受体堆栈如何影响其面外电荷传输能力，从而影响整体电导率，为下一代导电mof和COFs创造了一种新的设计策略。该项目还使PI能够履行其长期以来的承诺，即通过指导不同的研究人员群体执行复杂的多方面研究，培养能够引领未来创新的熟练劳动力，激励少数民族学生在stem领域接受高等教育，并通过在当地社区开展各种外展和教育活动，提高社会的科学意识。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。

项目成果

Rare Guest-Induced Electrical Conductivity of Zn-Porphyrin Metallacage Inclusion Complexes Featuring π-Donor/Acceptor/Donor Stacks

• DOI: 10.1021/acsami.3c15959
• 发表时间: 2023-12-18
• 期刊: ACS APPLIED MATERIALS & INTERFACES
• 影响因子: 9.5
• 作者: Benavides，Paola A.;Gordillo，Monica A.;Saha，Sourav
• 通讯作者: Saha，Sourav