Mechanics of Organic Mixed Ionic-Electronic Conductors (OMIECs)

这笔拨款将侧重于了解有机导体与离子和电子传导相互作用时的机械行为。有机离子-电子混合导体是有机电化学晶体管、电致变色器件、能量采集/存储和发光器件等有机电化学器件的核心功能部件。虽然目前对混合导体的研究大多集中在电荷和离子动力学上，但电子/离子导电与结构变化和机械变形之间的强耦合在很大程度上是未知的。该项目将制定一个理论框架和实验方案，以了解、评估和改进用于机械可靠、高性能有机电子的有机混合导体。这项研究将通过理论和实验方法的紧密结合，创造关于聚合物导体中同时存在的离子-电子输运和化学机械响应的基础知识。该项目的跨学科性质为不同层次的学生提供了独特的培训机会。与普渡大学女性工程项目合作的各种推广活动将侧重于少数族裔的参与，并将促进本科生和K-12学生对工程职业道路的兴趣。研究的总体目标是利用协调的多物理连续统理论、多尺度计算建模和实验验证来了解有机导体中电子、离子和机械响应之间的相互作用。该项目包括三项具体任务。(I)制定描述质量传输、电子/空穴传导和机械应力的基本物理的连续理论框架。建立有限元模型来模拟有机导体中的电化学/机械过程。对掺杂动力学和应力敏感动力学进行电化学/移动前沿实验，为理论提供理论支持。(Ii)通过原位纳米压痕和分子间相互作用的分子模拟等辅助工具，了解材料的力学本构行为和分子尺度结构-性能关系。(3)通过有限元分析和试验了解结构的力学损伤。进行机械测试以评估界面强度，进行循环伏安测试以评估电化学性能，并使用光学显微镜和吸收光谱来识别机械损伤。揭示了机械可靠性与器件性能之间的关系，确定了控制固态有机器件损伤萌生和演化的关键材料和几何参数。对有机混合导体力学的基本理解将使研究范式转向电化学设备中离子和电子同时传导和机械可靠性的完整设计范围。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。

This grant will focus on understanding the mechanical behavior of organic conductors in interaction with conduction of ions and electrons. Organic mixed ionic-electronic conductors are the core functional component of organic electrochemical devices such as organic electrochemical transistors, electrochromic devices, energy harvesters/storage, and light-emitting devices. While most efforts on mixed conductors are currently focused on the charge and ion dynamics, the strong coupling of the electronic/ionic conduction with structural changes and mechanical deformation is largely unknown. This project will formulate a theoretical framework and experimental protocols for the understanding, evaluation, and improvement of organic mixed conductors for mechanically reliable, high performance organic electronics. The research will create fundamental knowledge on the concurrent ionic-electronic transport and chemomechanical responses in polymeric conductors via a close integration of theoretical and experimental approaches. The interdisciplinary nature of the project provides unique training opportunities for students at different levels. The various outreach activities, in collaboration with the Women in Engineering Program at Purdue, will focus on the engagement of underrepresented minorities, and will promote the interest of undergraduate and K-12 students toward the engineering career pathway.The overarching goal of the research is to understand the interplay between electronic, ionic, and mechanical responses in organic conductors using coordinated multi-physics continuum theories, multi-scale computational modeling, and experimental validations. The project includes three specific tasks. (i) Formulate a continuum theoretical framework that describes the underlying physics of mass transport, electron/hole conduction, and mechanical stresses. Develop a finite element model to simulate the electrochemical/mechanical processes in organic comductors. Perform electrochemical/moving front experiments on the doping kinetics and stress-sensitive kinetics to feed the theory. (ii) Understand the mechanical constitutive behavior and the molecular-scale structure-property relationship through complementary tools of in-situ nanoindentation and molecular modeling on intermolecular interactions. (iii) Understand the mechanical damage using finite element analysis and experiments. Conduct mechanical tests to evaluate interfacial strength, perform cyclic voltammetry to evaluate the electrochemical performance, and employ optical microscope and absorbance spectroscopy to identify mechanical damage. Unravel the correlation between the mechanical reliability and device performance and determine the key material and geometrical parameters that govern the damage initiation and evolution in solid-state organic devices. The fundamental understanding on the mechanics of organic mixed conductors will shift the research paradigm towards a complete design spectrum of concurrent ionic and electronic conduction and mechanical reliability in electrochemical 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.