Conversion Processing of Functional Oxides to Oxyfluorides

复合氧化物在支撑现代社会的广泛技术中发挥着关键作用，这些技术在能源、通信和卫生部门的应用。用这些材料制作薄膜的能力将使其在电子和能源转换方面有新的应用。然而，为了充分利用氧化膜的潜力，需要新的加工方法来制造更广泛的材料组合物。该奖项支持基础研究，重点是开发和了解氟对氧的受控替代策略，从而使设计薄膜和纳米材料的电子、光学和磁性的新手段成为可能。将要研究的加工方法是可扩展的，需要最少的资本投资，并且可以在广泛的氧化膜上进行，而与材料最初的加工方式无关。因此，这项研究将直接支持国家的战略目标，即开发灵活的材料加工新方法，以减少从材料发现到技术部署的时间。这项研究还将为参与研究的学生的高级工程教育做出贡献，从而使美国经济受益。虽然沉积技术的进步使钙钛矿氧化物薄膜能够以单分子层的精度加工，但扩大获得新材料化学的途径仍然是一个挑战。这个项目的重点是氟对氧的取代，这允许控制过渡金属阳离子的价态和金属阴离子键的共价性，这两种效应都对电子、铁性和光学性质有深刻的影响。这项研究将阐明基于氧化物薄膜生长后转化反应合成氟氧化物混合阴离子钙钛矿的基本科学机理。要研究的转化过程利用含氟聚合物的蒸汽传输和阴离子扩散。该团队将沉积氧化膜，进行氟化反应，并利用光谱和结构表征技术来预测如何通过工艺条件来设计阴离子组成，以调整功能特性。

Complex oxides play a critical role in wide-ranging technologies that underpin modern society with applications in the energy, communications, and health sectors. The ability to make thin films of these materials will enable new applications in electronics and energy conversion. However, in order to fully harness the potential of oxide films, new processing approaches are required that will enable a wider range of material compositions to be manufactured. This award supports fundamental research focused on developing and understanding strategies for the controlled substitution of fluorine for oxygen, thereby enabling new means to engineer electronic, optical, and magnetic properties of thin films and nanomaterials. The processing methods to be studied are scalable, require minimal capital investment, and can be carried out on a broad range of oxide films, independent of how the materials were first processed. As such, the research will directly support the nation's strategic goal of developing agile new approaches for materials processing that can reduce the time from material discovery to technological deployment. The research will also benefit the U.S. economy by contributing to the advanced engineering education of the participating students. While advances in deposition techniques have enabled the processing of perovskite oxide films with monolayer precision, expanding access to new material chemistries remains a challenge. This project is focused on the substitution of fluorine for oxygen, which allows for control of the transition metal cation valence state and the covalency of the metalanion bond, both effects having profound implications for electronic, ferroic, and optical properties. This research will elucidate fundamental scientific mechanisms in the synthesis of oxyfluoride mixed-anion perovskites based on post-growth conversion reactions of oxide films. The conversion processes to be studied utilize vapor transport and anion diffusion from fluoropolymers. The team will deposit oxide films, carry out fluorination reactions, and utilize spectroscopic and structural characterization techniques to develop a predictive understanding of how the resultant anion composition can be engineered through processing conditions to tune functional properties.