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.

非技术总结维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。金属有机骨架（MOFs）和共价有机骨架（COFs）具有合成易接近性、结构模块性和功能可调性等特点，有望成为下一代电子和储能器件的活性组分。然而，导电性-电荷载流子浓度和迁移率的产物-仍然是MOFs和COFs最难以捉摸的特征之一，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这种非常理想的电子特性。在材料研究部门的固态和材料化学计划以及刺激竞争力研究的既定计划（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，通过将共面堆叠的交替富电子（π-供体）和电子缺陷（π-受体）阵列，然后在这些固态材料中利用它们的有效的通过空间电荷离域能力，这有望产生有前途的本征导电性。该研究项目不仅生产具有独特结构和成分的新型导电2D MOFs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电荷在两个正交方向上分别通过分层网络和π-供体/受体堆叠的传输，从而提高这些新兴智能材料的体电导率。这个NSF资助的项目还使PI能够通过参与和指导研究生，本科生，博士后和高中学生进行尖端材料研究，为未来的创新培养熟练的劳动力，激励代表性不足的少数民族在STEM领域接受高等教育，并通过当地学校，科学博物馆和公共论坛的各种教育和宣传活动提高社会的科学意识。由于它们作为现代电子和能量存储装置的活性组分的不同潜力，导电金属有机框架（MOF）和共价有机框架（COF）已经成为最令人垂涎和探索的功能材料。然而，作为电荷载流子浓度和电荷迁移率的函数的电导率仍然是这些多孔结晶骨架材料的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π键发生在平面内和/或通过π堆叠层发生在平面上，而在2D COF中，后者代表主要的传输路径。在两个正交方向上的面内和面外电荷传输之间的大差异通常使得这些材料的导电率高度各向异性（即，方向相关）并抑制它们的整体体电导率。为了解决这些问题并同时促进平面内和平面外电荷传输，从而在2D MOF和COF中产生更高的体电导率，在NSF固态和材料化学（SSMC）计划支持的该项目中，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π-供体/在2D层状框架内的受体堆叠可以促进面外电荷传输，使这种通常效率较低的路径与贯穿键传导路径相当。了解由嵌入2D MOF和COF中的不同互补π供体和受体单元组成的π供体/受体堆叠如何影响其面外电荷传输能力，从而整体体电导率正在为下一代导电MOF和COF创造新的设计策略。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执行复杂的多方面研究，激励少数民族学生在STEM中接受高等教育，通过在当地社区开展各种推广和教育活动，提高社会的科学意识。该奖项反映了NSF的法定使命，并被认为是值得的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，

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