Excellence in Research: Structure and Dynamics of Exciplexes in Thermally Activated Delayed Fluorescence

卓越研究：热激活延迟荧光中激基复合物的结构和动力学

• 批准号: 2200387
• 负责人: Seyhan Salman
• 金额: $ 32万
• 依托单位: Clark Atlanta University
• 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=2200387&HistoricalAwards=false
• 关键词: Excellence; Research; Structure; Dynamics; Exciplexes

In this project, jointly funded by the Office of Integrative Activities (OIA), the Chemical Structure, Dynamics, and Mechanisms-A (CSDM-A) program in the Division of Chemistry, and the Electronic and Photonic Materials (EPM) program in the Division of Materials Research, Seyhan Salman and her research group at Clark Atlanta University are using theoretical models and computational tools to investigate the electronic structure and optical properties of organic light-emitting diode (OLED) materials that exhibit thermally activated delayed fluorescence (TADF). The project seeks to significantly advance the understanding of excited-state complexes (exciplexes) that are responsible for TADF based on their electronic structures and optical properties, as well as the various transition processes associated with the excited complexes. Better understanding of the fundamental structure and dynamics of such species will help guide the development of efficient new materials for applications in optical and electronic devices, including OLEDs, solar cells, field-effect transistors, (bio)chemical sensors and storage devices. The project also provides students from groups that are underrepresented in science with a challenging research experience and professional training in computational materials chemistry that will help prepare them for the STEM (science, technology, engineering and mathematics) workforce.The main goal of this project is to elucidate the excited-state dynamics of thermally activated delayed fluorescence (TADF) in exciplex-based OLED materials. Such systems represent one of the most promising classes of materials for realizing highly efficient OLEDs using organic molecules and could lead to a significant reduction in fabrication costs associated with this technology. The electronic structure and properties of exciplexes are influenced by the intermolecular interactions in the exciplex state, which are markedly different than that in the ground state and are relatively weak, leading to various structural conformations. Further studies of exciplexes, including their electronic structures, properties, and dynamics of charge and energy transfer processes, are needed for their application in OLEDs. This project uses state-of-the-art computational approaches with the goal of quantifying microscopic parameters and establishing structure-property relationships in these materials. The research team uses an integrated approach combining all-atom molecular dynamics (AA-MD) simulations with density functional theory (DFT) calculations to study the effect of the solid matrix environment on the emissive properties of exciplexes. They are also examining the impact of energetic disorder (static and dynamic components) on the efficiency of radiative decay processes. The impacts of host-guest interactions and the dynamics of charge- and energy-transfer processes are also included in the modeling scheme in order to account for intersystem crossing and other radiative and non-radiative transitions.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.

该项目由综合活动办公室（OIA）、化学部的化学结构、动力学和机理- a （CSDM-A）项目和材料研究部的电子和光子材料（EPM）项目共同资助，克拉克亚特兰大大学的Seyhan Salman和她的研究小组正在使用理论模型和计算工具来研究表现出热激活延迟荧光（TADF）的有机发光二极管（OLED）材料的电子结构和光学特性。该项目旨在根据其电子结构和光学性质，以及与激发态复合物相关的各种过渡过程，显著推进对负责TADF的激发态复合物（激复合物）的理解。更好地了解这些物种的基本结构和动力学将有助于指导开发用于光学和电子设备的高效新材料，包括oled，太阳能电池，场效应晶体管，（生物）化学传感器和存储设备。该项目还为来自科学领域代表性不足的群体的学生提供具有挑战性的研究经验和计算材料化学方面的专业培训，这将有助于他们为STEM（科学、技术、工程和数学）劳动力做好准备。本项目的主要目标是阐明热激活延迟荧光（TADF）的激发态动力学。这种系统代表了使用有机分子实现高效oled的最有前途的材料类别之一，并且可以显著降低与该技术相关的制造成本。异构体的电子结构和性质受异构体分子间相互作用的影响，异构体的分子间相互作用与基态的分子间相互作用明显不同，且相对较弱，导致了不同的结构构象。杂络合物在oled中的应用需要进一步的研究，包括它们的电子结构、性质、电荷和能量传递过程的动力学。该项目使用最先进的计算方法，目标是量化这些材料的微观参数并建立结构-性能关系。研究团队采用全原子分子动力学（AA-MD）模拟与密度泛函理论（DFT）计算相结合的综合方法，研究固体基质环境对杂合体发射特性的影响。他们还在研究能量紊乱（静态和动态成分）对辐射衰变过程效率的影响。为了考虑系统间交叉和其他辐射和非辐射转变，建模方案中还包括主-客体相互作用的影响以及电荷和能量转移过程的动力学。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

Identifying the origin of delayed electroluminescence in a polariton organic light-emitting diode

• DOI: 10.1515/nanoph-2023-0587
• 发表时间: 2023-09
• 期刊: Nanophotonics
• 影响因子: 7.5
• 作者: A. Abdelmagid;Hassan A. Qureshi;Michael A. Papachatzakis;Olli Siltanen;Manish Kumar;Ajith Ashokan;Seyhan Salman;K. Luoma;Konstantinos S. Daskalakis