CAREER: Guiding automated synthesis of hybrid perovskites towards stability via knowledge of nanoscale ionic mechanisms

金属卤化物钙钛矿是一类新型的无机和有机杂化材料，具有革新光电子技术的潜力。他们对下一代廉价、高效的太阳能电池表现出了特别的希望。钙钛矿广泛使用的主要限制因素是它们在设备中不稳定。这个项目将加深对钙钛矿的基本和特殊性质的了解，主要目标是提高稳定性。本项目将阐明和描述这些材料的电化学，为开发制造稳定的钙钛矿的新工艺提供信息。这项工作是通过一种创新的自动合成方法实现的，这种方法允许对各种新的成分进行实验，否则很难识别和研究这些成分。国际和平研究所将通过一个积极的、以项目为基础的外展计划，努力提高妇女对材料科学和工程研究事业的兴趣和参与。该计划将包括为高中生和本科生提供个性化的职业意识指导。有机-无机卤化物钙钛矿(OIHP)具有许多理想的光电应用，用于改善太阳能电池、光电探测器和发光二极管的性能和降低成本。OIHP广泛商业化使用的主要障碍是它们的不稳定性和较低的长期绩效。对离子化学的精确控制和对界面和表面化学如何影响功能的了解是克服这些限制的关键。该项目将测量和描述影响OIHP内在稳定性的潜在机制，以创建预测模型，为耐用材料的设计提供信息。与OIHP稳定性相关的三个挑战是：1)建立用于材料发现和优化的快速指导的自动组合合成流程；2)通过电化学门控实验确定离子化学的作用；3)描述三相结上界面电化学过程的动力学和热力学。该项目将使用显微技术和手术中设备的成像来建立对OIHP系统内部电化学功能的全面了解，这将使我们能够找到一条通往预测建模和工艺优化的道路。建议的自动化合成方法使用快速表征和缓慢的设备测试，将允许导航这些材料的成分和加工空间。基于项目的推广计划将把电子和离子电荷传输的物理学与机器学习概念结合起来，为本科生和研究生提供新的研究体验。这些活动的适当版本将提供给感兴趣的女高中生，以提高女性和其他在STEM中代表性不足的群体对材料科学职业的兴趣并为其做好准备。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。

Metal halide perovskites are a new class of hybrid materials with inorganic and organic components with the potential to revolutionize optoelectronic technologies. They have shown particular promise for the next generation of inexpensive, efficient solar cells. The primary limiting factor to widespread use of perovskites is that they are not stable in devices. This project will develop an understanding of the fundamental and specific properties of perovskites with an overarching goal of improved stability. This project will elucidate and describe the electrochemistry of these materials to inform development of new processes for manufacture of stable perovskites. This work is made possible by an innovative automated synthesis approach that allows for experimentation on a diverse range of novel compositions that would be difficult to identify and study otherwise. The PI will strive to increase interest and participation of women in materials science and engineering research careers through an active, project-based outreach program. This program will include individualized career awareness mentoring for high school students and undergraduates.Organic–inorganic halide perovskites (OIHP) have many qualities that are ideal for optoelectronic applications and are used to improve function and reduce cost of solar cells, photodetectors, and light-emitting diodes. The substantive hurdles to widespread, commercial use of OIHPs are their instability and low long-term performance. Precise control of ionic chemistry and understanding of how interfacial and surface chemistry affects function are essential to overcome these limitations. This project will measure and describe the underlying mechanisms that affect OIHP intrinsic stability to create predictive models that will inform design of durable materials. The three challenges related to the stability of OIHPs examined in this project are: 1) establish rapid guided automated combinatorial synthesis workflow for material discovery and optimization, 2) determine the role of ion chemistry via electrochemical gating experiments, and 3) describe the kinetics and thermodynamics of the interfacial electrochemical processes on the three-phase junctions. The project will employ microscopy techniques and imaging of in-operando devices to build a comprehensive understanding of the internal electrochemical functionality of OIHP systems, which would enable a path toward predictive modelling and optimization of processing. The proposed automated synthesis approach using rapid characterization and slow device testing will allow for navigation of the compositional and processing space of these materials. The project-based outreach program will integrate the physics of electronic and ionic charge transports with machine learning concepts for new research experiences for undergraduate and graduate students. Grade-level appropriate versions of these activities will be offered to interested female high school students to increase interest in and improve preparation for materials science careers for women and other groups underrepresented in STEM.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.