碳基材料原子尺度低损伤透射电子显微分析

Atomic-scale investigation of carbon-based materials by gentle transmission electron microscopy

近年来,石墨烯、金属有机框架(MOFs)、聚合物、生物大分子等碳基材料在物理、化学、材料、生物学等领域受到了持续增长的关注,但由于其微观结构在电子束辐照下的不稳定性导致原子分辨率的实验观察仍面临巨大的挑战。原子结构的认识不足严重限制了对此类材料的深入理解及潜在应用研究。近年来,低加速电压、低电子剂量与低温电子显微学(TEM)亚埃分辨率的革命性突破,极大地促进了对电子束敏感材料结构与化学组成的原子尺度解析。特别是对轻元素原子成像的能力有助于深入研究新型碳基材料的结构和性能。本文总结了先进电子显微学中各种成像与谱学技术的新进展,及其在石墨烯基材料、MOFs、聚合物、生物大分子等碳基材料研究中的应用,并探讨了当前材料研究面临的挑战与电子显微学的发展趋势,以期助力对新型碳基材料构效关系的深入理解和设计开发。

Although carbon-based materials,such as graphene,metal-organic frameworks(MOFs),polymers and biomolecules,have aroused increasing scientific interest in the fields of physics,chemistry,materials science and molecular biology,their atomicscale observation is still a challenge due to their structural instability under the electron beam.Ambiguous atomic arrangements have critically limited the fundamental understanding on these materials and their potential applications in electronics,mechanics,thermodynamics,catalysis,bioscience and medicine.Very recently,revolutionary sub-?ngstr?m resolution achievements of transmission electron microscopy(TEM)using a low voltage,a low electron dose,or a cryogenic environment have greatly facilitated the atomicscale structural and chemical examination of electron beam sensitive materials.In particular,the ability to image light elements atom by atom gives unprecedented insight into the structures and properties of novel carbon-based materials.In this review,the recent developments in advanced TEM combined with various imaging and spectroscopy techniques,and their use in examining graphenebased materials,MOFs,polymers,and biomacromolecules are summarized and discussed.The current challenges in materials research and trends for the future design of TEM equipment are outlined,which is expected to provide a deeper understanding of structure–performance relationships and the discovery of new carbon materials.