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.

非技术总结保持现代电子和清洁能源技术的快速发展，需要不断创新和供应易于获得的智能材料，这些材料可以以可编程的方式运输和存储电荷。金属有机骨架(MOF)和共价有机骨架(COF)由于其合成的可及性、结构的模块化和功能的可调性，在作为下一代电子学和储能器件的活性元件方面具有巨大的潜力。然而，导电性--载流子浓度和迁移率的产物--仍然是MOF和COF最难以捉摸的特性之一，这促使研究人员设计出新的设计和合成策略，在这些晶体框架材料中设计这种非常理想的电子性能。在材料研究部固态与材料化学项目和已建立的促进竞争研究计划(EPSCoR)的支持下，克莱姆森大学的萨哈教授和他的研究小组正在开发和实施一种新的设计策略，通过结合表面堆叠的交替富电子(pi-施主)和低电子(pi-接受者)阵列，然后利用它们高效的穿过空间电荷离域的能力，促进二维(2D)MOF和COF中的长程面外电荷传输，有望产生良好的本征导电性。该研究项目不仅正在开发具有独特结构和组成的新型导电2D MOF和COF，而且还创造了一种创新的设计策略，可以分别通过分层网络和pi施主/受主堆栈在两个垂直方向上同时促进面内和面外电荷传输，从而提高这些新兴智能材料的体电导率。这一由美国国家科学基金会资助的项目还通过吸引和指导研究生、本科生、博士后和高中生从事尖端材料研究，鼓励未被充分代表的少数群体在STEM接受高等教育，并通过在当地学校、科学博物馆和公共论坛开展各种教育和外联活动，使PI能够为未来的创新培养熟练的劳动力，并提高对社会的科学认识。技术综述导电金属有机骨架(MOF)和共价有机骨架(COF)因其作为现代电子学和储能器件的活性元件的不同潜力而成为最令人垂涎和开发的功能材料。然而，电导率是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，主要是因为它们往往缺乏有效的电荷传输路径。在二维(2D)MOF中，电子传导可以通过配位和共轭的pi键发生在平面内，和/或通过pi堆积层发生在平面之间，而在2DCOF中，后者是主要的输运途径。两个垂直方向的面内和面外电荷输运之间的巨大差异往往使这些材料的电导率高度各向异性(即与方向有关)，并抑制其整体电导率。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2D MOF和COF的体电导率，在NSF固态和材料化学(SSMC)计划的支持下，Sourav Saha教授和他在克莱姆森大学的研究小组正在探索新颖的设计和合成策略，通过将内置交替的pi施主/受主堆栈纳入2D分层框架中，可以促进面外电荷传输，从而使这一效率通常较低的途径与通键传导途径相同。了解嵌入在2D MOF和COF中的由不同互补的pI施主和受主单元组成的pi施主/受主堆栈如何影响它们的面外电荷传输能力，从而为下一代导电MOF和COF创造一种新的设计策略。该项目还使PI能够履行其长期承诺，通过指导不同的研究人员团队进行复杂的多方面研究，激励少数族裔学生继续接受高等教育，并通过当地社区的各种外展和教育活动提高一个具有科学意识的社会，从而培养能够引领未来创新的熟练劳动力。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势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