Connecting Junction Molecular Orientation to Excited State Structure and Dynamics in Organic Devices

基于柔性有机材料的可印刷电子设备有可能彻底改变我们可再生获取和储存能源的方式。层与层之间的界面上塑料分子的排列可以决定器件的性能是否良好。然而，目前关于这种安排如何影响器件性能的知识有限。在这个项目中，研究了用塑料墨水印刷的太阳能电池和发光体。这些设备有重要的接口，在那里发电和光发射。这个项目包括改变这些界面上分子的排列，由强大的x射线技术监测。相应地，产生能量和光的过程被测量并与分子的排列有关。结果将是一种新的能力来定制界面上的分子排列，以最大限度地提高设备性能。这种能力将使灵活的可打印技术大大降低能源成本。参与该项目的学生将通过为高中生开发塑料太阳能电池实验室来参与科学大使计划。这项活动将展示基础科学和这些技术的潜力。该项目的跨学科和协作性质将为学生提供专业知识，以交流下一代科学家所需要的不同观点。可印刷有机器件的光电特性可以通过简单的加工技术来设计界面结构，以适应革命性的应用，但在实现这一目标的知识上存在空白。这种差距是由于难以定量解析埋藏的有机界面纳米结构并将其直接与基本器件工艺相关联。在提出的工作中，一套最近开发的共振x射线纳米探针将用于量化分子取向、聚集和局部与埋藏有机界面的混合。这些测量将与激发态结构和动力学的先进研究相结合，在完全相同的设备上消除与样品可变性相关的不确定性。目的是确定在埋藏有机结的分子排序如何控制与性能相关的激发态动力学的定量关系。它将通过系统地研究平面结中的所有结构案例并将这些信息扩展到打印的3D异质结中来完成。我们的目标不仅是建立一般概念，而且要定义这些关系的功能形式，以实现高性能有机器件的设计特性。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。

Printable electronic devices based on flexible organic-based materials have the potential to revolutionize how we renewably harvest and store energy. The arrangement of plastic molecules at interfaces between layers can determine whether the device performs well. However, there is currently limited knowledge of how such arrangements govern device performance. In this project, solar cells and light emitters printed from plastic inks are studied. These devices have important interfaces where power is generated and light is emitted. This project involves varying the arrangement of the molecules at these interfaces, monitored by powerful X-ray techniques. Correspondingly, power- and light-generating processes are measured and related to the arrangement of the molecules. The result will be a new capability to tailor molecule arrangements at interfaces to maximize device performance. Such a capability will enable flexible and printable technologies to dramatically reduce the cost of energy. Students involved in this project will take part in the Science Ambassadors Program by developing a plastic solar cell lab for high school students. This activity will demonstrate both the fundamental science and the potential of these technologies. The interdisciplinary and collaborative nature of the project will provide the students with expertise to communicate diverse viewpoints that will be required of the next generation of scientists.Optoelectronic properties in printable organic devices could be tailored for revolutionary applications through simple processing techniques that engineer interfacial structures, but there is a gap in knowledge to realize this goal. This gap is due to the difficulty in quantitatively resolving buried organic interfacial nanostructure and directly correlating this to fundamental device processes. In the proposed work, a suite of recently developed resonant X-ray nanoprobes will be used to quantify molecular orientation, aggregation, and mixing local to buried organic interfaces. These measurements will be combined with advanced studies of excited state structure and dynamics on the exact same device - eliminating uncertainties related to sample variability. The objective is to define quantitative relationships on how molecular ordering at buried organic junctions controls excited state dynamics connected to performance. It will be accomplished by systematically investigating all structural cases in planar junctions and extending this information to printed 3D heterojunctions. Our aim is not only to establish the general concepts, but to define the functional form of these relationships to enable designed properties in high-performing organic devices.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.