CAREER: Stretchable Light-Emitting Polymers with Thermally Activated Delayed Fluorescence

第一部分：对于人体集成的可穿戴和可植入电子器件，发光器件（例如有机发光二极管，OLED）在诸如显示器、基于光的生命体征监测和疾病治疗、生物成像和细胞活动的光学生物刺激的应用中发挥重要作用。为了使这些装置具有适形的皮肤/组织接触和长期相容性，关键要求之一是具有类似组织的机械拉伸性。然而，迄今为止，所有高性能的无机和有机发光材料都相对刚性和脆性。这项研究将开发和研究一类新的聚合物，将高效发光机制与橡胶般的机械性能结合起来。这些新的聚合物将通过新结构的化学合成和现有化学结构的物理工程来创建。通过对不同橡胶结构对发光性能影响的基础研究，本研究将为这类新型聚合物提供设计原则，以实现发光器件的高效率和高拉伸性。通过这项研究，可拉伸发光技术可能会影响精密医疗，人机交互和人工智能等新兴领域。这项研究将丰富研究生和本科生的教育和培训，并通过与高中和芝加哥南区科学与工业博物馆的合作，促进代表性不足的少数民族（URM）学生参与STEM研究。 第二部分：可拉伸发光器件代表了人类集成电子器件的新兴领域中的重要组件，其期望实现皮肤/组织样机械性能和生物相容性。然而，对于电致发光性能，实现和理解的影响，将机械可拉伸的分子设计上的电致物理行为仍然很少。本研究旨在建立一套材料设计原则，将应变耗散机制整合到最先进的一类发光材料中，即“热激活延迟荧光”（TADF）聚合物，从而将联合收割机的皮肤样拉伸性与高电致发光效率结合起来。具体而言，本研究将探索和研究赋予TADF聚合物拉伸性的四种一般方法：1）化学调节聚合物主链的柔性; 2）化学构建聚合物侧链的柔性; 3）物理松动链间包装和相互作用; 4）赋予TADF发射体的“主体”聚合物拉伸性。通过这四种方法的新聚合物设计，本研究将通过结合多方面的实验表征和理论模拟，对TADF聚合物的结构-性能关系进行基础研究，该结构-性能关系结合了联合收割机热力学、机械和电致发光方面。这项研究还将在本科和研究生阶段培养未来的劳动力，特别是新兴的可穿戴和植入式电子行业。PI还将制定一项新计划，将STEM研究带到芝加哥南区的高中生中，那里的少数民族比例很高，同时还将为“科学与工业博物馆，芝加哥”该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的评估被认为值得支持。影响审查标准。

PART 1: NON-TECHNICAL SUMMARY For human-integrated wearable and implantable electronics, light-emitting devices (such as organic light-emitting diodes, OLEDs) play important roles for applications such as displays, light-based vital-sign monitoring and disease therapy, bio-imaging, and optical bio-stimulation of cell activities. For these devices to have conformable skin/tissue contacts and long-term compatibility, one of the key requirements is to have tissue-like mechanical stretchability. However, all the high-performance light-emitting inorganic and organic materials available so far are relatively rigid and brittle. This research will develop and study a new class of polymers that combines high-efficiency light-emitting mechanisms with rubber-like mechanical properties. These new polymers will be created through both the chemical synthesis of new structures and the physical engineering of existing chemical structures. Through fundamental studies on the influence of different rubbery designs on light-emitting performance, this research will provide design principles for this new class of polymers for achieving both high efficiency in light-emitting devices and high stretchability. Enabled by this research, the stretchable light-emitting technology could impact the emerging areas of precision healthcare, human-machine interactions, and artificial intelligence. This research will enrich the education and training for graduate and undergraduate students, as well as promote the participation of underrepresented minority (URM) students in STEM research through partnerships with high schools and the Museum of Science and Industry in Chicago's South Side. PART 2: TECHNICAL SUMMARY Stretchable light-emitting devices represent an important component in the emerging area of human-integrated electronics that are desired to achieve skin/tissue-like mechanical properties and biocompatibility. However, for electroluminescent properties, the realization and understanding of the impacts of incorporating mechanically stretchable molecular designs on photophysical behaviors remain rare. This research aims to create a set of material design principles for integrating strain-dissipation mechanisms into a state-of-the-art category of light-emitting materials, that is "thermally activated delayed fluorescence" (TADF) polymers, so as to combine skin-like stretchability with high electroluminescence efficiencies. Specifically, this research will explore and study four general approaches for imparting stretchability onto TADF polymers: 1) chemically modulating the flexibility of polymer backbones; 2) chemically building flexibility onto polymer side chains; 3) physically loosening the interchain packing and interaction; 4) imparting stretchability onto “host” polymers for TADF emitters. Enabled by the new polymer designs from these four approaches, this research will carry out fundamental studies on the structure-property relationships that combine thermodynamic, mechanical, and electroluminescent aspects for TADF polymers by combining multi-aspect experimental characterizations and theoretical simulations. This research will also develop the future workforce at both undergraduate and graduate levels, with special relevance to for the emerging wearable and implantable electronics industry. The PI will also develop a new program for bringing STEM research to high school students in Chicago's South Side which have a high proportion of underrepresented minorities, as well as the development of scientific exhibits and public lectures for the “Museum of Science and Industry, Chicago”.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.