SnSe基层状材料原子尺度微结构与氧化机制的电子显微学研究

SnSe-based alloys with layered structure have been intensively studied due to their outstanding performance and potential for application in the field of thermoelectric materials. However, oxidation corrosion will change the surface microstructure and thereby worsen the thermoelectric performance. The knowledge of microstructures (especially at atomic scale) is a key point to understanding the outstanding thermoelectric performance as well as complex oxidation behaviors for the SnSe-based materials and other similar materials. In this project, a comprehensive research method based on electron microscopy are used to solve the following issues. The atomic-scale microstructure (such as vacancies, interstitial atoms, lattice distortion, strain field, etc.) will be systemically studied by the Cs-STEM, which gives qualitative and quantitative information of structure defects. In-situ oxidation studies will be conducted through environmental transmission electron microscopy (ETEM) or in-situ atmosphere chips with help of in-situ heating chips. The oxidation behavior about the atomic configuration, chemistry and electron structure of the surface, as well as the related basic science behind will be analyzed based on the experiment data and theoretical studies. The achievements of this project will promote the insights into atomic structure and oxidation behavior of SnSe-based layered materials as well as similar materials. In addition, the above results could speed up the commercial applications of SnSe-based and related materials. Meanwhile, it is of great significance to study the surface gas corrosion of other materials.

SnSe基层状材料因其显著的热电性能与应用潜力而备受关注。氧化腐蚀的发生将改变材料表面显微组织结构，同时降低热电转化效率。原子尺度显微结构及其演变规律的研究，是解析SnSe及相似体系材料优异性能与复杂氧化行为的关键。本项目拟依托以电子显微学为主的综合研究方法，首先系统开展SnSe体系材料原子尺度显微结构（如各类点缺陷、晶格畸变、应力场分布等）的研究，再进行氧化行为与微观机理的原位探索，剖析氧化腐蚀过程中材料表面原子结构、电子结构的动态变化过程，以解析材料的微观氧化机制及相关的物理、化学等基础科学问题，为材料性能优化与氧化行为调控提供指导。本项目的实施，有望深化对SnSe及相似体系材料的显微结构与氧化腐蚀行为的认识与理解，为相关材料的进一步发展与商业应用奠定基础，同时对其他材料的表面气体腐蚀现象的研究具有重要借鉴意义。

范德华层状材料因其独特的结构与物理化学性质而广受关注，而氧化的发生容易诱发表面结构的改变而对材料原有性能产生严重影响，因此氧化行为的研究对其性能的理解与实际应用至关重要。本项目以SnSe为主要研究对象，通过综合的电子显微分析方法，解析了相关材料的氧化行为与表面微结构，结合球差校正技术、电子束辐照原位实验与显微图像定量分析方法，从原子尺度解析了SnO2/SnSe2/SnSe多层异质结及SnSe2与SnSe外延生长关系，揭示了SnSe表面氧化微观机制，并提出了利用SnSe氧化行为实现表面结构可控生长与材料性能调控的构想。类似的研究结果在InSe、GaSe等层状硒化物中也得到了很好的印证，其结果显示随着表面氧化的发生材料表面均形成了多层异质结构，且不同温度下的表面多层氧化结构具有良好的重复性。本项目为范德华层状材料氧化行为与机制的认识提供了重要的参考，同时为该类材料的表面工程与实际应用提供了重要思路与指导。