CAREER: Exploiting Open-Shell Character for Organic Optoelectronic Applications

在化学系化学结构、动力学和机理B项目以及材料科学系电子和光子材料项目的支持下，利哈伊大学的Mark Chen博士将开发新的碳基材料，利用具有不成对电子特征的新型分子自由基的特性。大多数有机分子只含有自旋配对的电子。这确保了环境的稳定性，但限制了分子材料用于光电子应用的能力。在这个项目中，陈博士和他的学生们正在使用合理的设计原则来构建新的分子自由基，这些自由基有望具有高环境稳定性，最终在用作发光和电荷传输材料时提高器件性能。该项目涉及化学合成的组合，随后进行物理表征研究，以确定和优化分子结构和性能。这种跨学科研究促进了教育课程材料的开发，旨在激励科学、技术、工程和数学(STEM)的学生超越正规学科的界限进行思考。将通过旨在从大西洋中部地区招募在STEM领域任职人数不足的学生团体的外联活动，促进STEM内部的相互联系。该项目的研究活动旨在开发能够利用开壳电子结构效应的新的电子材料。为了稳定，大多数有机分子都具有闭壳电子结构，其中分子中的所有电子都是自旋配对的。由于与发射机制和电荷转移动力学相关的不利能量，这固有地限制了光电子的应用。在这个项目中，陈教授和他的学生将合成并系统地探索空气稳定的、具有持久不成对自旋的双苯基结构的pi共轭分子的结构-性质关系。这项研究建立在陈研究小组已经开发的一条有效的合成路线上。双苯基结构的合成修饰旨在控制发光过程中的发射波长和量子效率，同时还可以增强电荷传输过程中的电子迁移率和电导率。该项目的研究有望通过引入更便携、更节能、制造成本更低的新光电子材料和设备来影响社会。这种跨学科的研究依赖于化学合成和多样化的物理表征方法，为研究生和本科生提供了多样化的专业培训机会。新的课程和推广计划将激励学生培养对STEM职业的更广泛兴趣。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。

With support from the Chemical Structure, Dynamics, and Mechanisms B Program in the Division of Chemistry and the Electronic and Photonic Materials Program in the Division of Materials Science, Dr. Mark Chen at Lehigh University will develop new carbon-based materials that exploit properties of novel molecular radicals which have unpaired electron character. Most organic molecules only contain spin-paired electrons. This ensures environmental stability but limits the capabilities of molecular materials for optoelectronic applications. In this project, Dr. Chen and his students are using rational design principles to construct new molecular radicals that are expected to have high environmental stability, ultimately leading to enhanced device performance when employed as luminescent and charge transport materials. The project involves a combination of chemical synthesis, followed by physical characterization studies to identify and optimize molecular structures and properties. This interdisciplinary research facilitates the development of educational course materials, which are designed to inspire science, technology, engineering and mathematics (STEM) students to think outside the boundaries of formal disciplines. Interconnections within STEM will be promoted through outreach events aimed at recruiting student groups from the mid-Atlantic region who are underrepresented in STEM fields. Research activities in this project are aimed at the development of new electronic materials which can exploit the effects of open-shell electronic structure. For stability, most organic molecules possess closed-shell electronic structures, where all electrons within a molecule are spin-paired. This inherently limits optoelectronic applications due to unfavorable energies related to emission mechanisms and charge transfer kinetics. In this project, Professor Chen and his students will synthesize and systematically explore the structure-property relationships of air-stable, pi-conjugated molecules with bisphenalenyl structures that possess persistent unpaired spin. This research builds on an efficient synthetic route already developed by the Chen research group. Synthetic modifications of bisphenalenyl structures are designed to control emission wavelength and quantum efficiencies during luminescence, while also enhancing electron mobilities and conductivities during charge transport. Research in this project is expected to impact society by introducing new optoelectronic materials and devices that are more portable, energy efficient, and less expensive to manufacture. This interdisciplinary research, which relies on chemical synthesis and diverse methods of physical characterization, provides diverse professional training opportunities for graduate and undergraduate students. New curricula and outreach programs will inspire students to cultivate broader interests in STEM careers.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.