EAGER: Structural Development of Organometal Halide Perovskites for Thin-film Photovoltaics

摘要：在全球经济增长的推动下，能源需求的不断增长，目前主要由传统能源来满足，这将通过飙升的油价、污染和不稳定的气候变化使社会日益紧张。作为一种可行的替代能源，太阳能是最有力的竞争者之一。目前太阳能发电的领跑者是晶体硅光伏。有希望大幅降低加工和制造成本，并迅速提高效率；基于有机金属卤化物钙钛矿的薄膜光伏电池有望成为有吸引力的替代品。然而，有大量的技术瓶颈阻碍了薄膜钙钛矿光伏电池的大规模部署。其中包括器件稳定性和单个批次内以及批次之间性能的广泛变化，这归因于钙钛矿活性层的形态。本EAGER提案旨在阐明薄膜钙钛矿的结构发展，其结果将有助于器件性能和稳定性的变革性改进。技术：钙钛矿薄膜的结构非均质性跨越多个长度尺度；其发展内容丰富、复杂，对加工条件高度敏感。钙钛矿薄膜的结构发展与诱导钙钛矿形成的化学反应同时发生。利用首席研究员在聚合物和有机电活性材料的解耦膜形成和结构发展方面的经验，他们将量化钙钛矿活性层形成的动力学，他们将阐明机制并对过程进行控制，使用原位和非原位x射线衍射以及高分辨率显微镜技术的组合。从这项工作中收集到的加工-结构-功能关系将带来稳定所需形态的方法，从而提高钙钛矿光伏电池的稳定性和可靠性。这个EAGER项目是高度跨学科和垂直整合的。参与的学生将有第一手的机会接触到钙钛矿及其前体的化学合成；定量结构表征与分析；以及设备制造和测试。

Abstract:Nontechnical:The ramping energy demand - spurred by global economic growth, and so far largely met by conventional energy sources - will increasingly strain society through soaring oil prices, pollution, and destabilizing climate change. Solar energy is amongst the top contenders as a viable alternative energy source. The current front-runner for solar power generation is crystalline silicon photovoltaics. With the promise of substantially lower processing and manufacturing costs and rapidly increasing efficiencies; thin-film photovoltaics based on organometal halide perovskites promise to be attractive alternatives. Yet, there are substantial technological bottlenecks that prevent the wide-scale deployment of thin-film perovskite photovoltaics. Among them are device stability and the widespread variability in performance within a single batch and between batches of devices, which have been attributed to the morphology of the perovskite active layers. This EAGER proposal aims to elucidate the structural development of thin-film perovskites, the results of which should facilitate a transformative improvement in device performance and stability.Technical:Structural heterogeneities in perovskite thin films span multiple length scales; its development is rich and complex and highly sensitive to processing conditions. The structure development of thin films perovskite is simultaneously taking place with an ongoing chemical reaction that induces the perovskite formation. Leveraging the principal investigator's experience in decoupling film formation and structure development in polymer and organic electrically active materials, they will quantify the kinetics of perovskite active layer formation, with which they will elucidate the mechanism and impart control over the process, using a combination of in- and ex-situ x-ray diffraction as well as high-resolution microscopy techniques. The processing-structure-function relationships gleaned from this undertaking will bring about approaches to stabilize the desired morphology and thus improve the stability and reliability of perovskite photovoltaics. This EAGER project is highly interdisciplinary and vertically integrated. The students involved will have first-hand exposure to chemical syntheses of perovskites and their precursors; quantitative structural characterization and analyses; and device fabrication and testing.