Graphene Liquid Cells for In Situ Transmission Electron Microscopy: Unveiling Nanomaterial Growth and Etching

The liquid‐phase growth and etching process of nanomaterials profoundly affects their size, morphology, and composition, thereby determining their properties. Achieving real‐time atomic‐resolution visualization of these processes has driven the development of in situ liquid‐phase transmission electron microscopy imaging. Especially, graphene liquid cells (GLCs) have emerged as a powerful platform due to their high resolution, facile fabrication, and compatibility with conventional transmission electron microscopy holders. This review first summarizes the preparation of suspended graphene, the key window material for GLCs, and the fabrication of GLCs with diverse configurations. It then systematically outlines the applications of GLCs in revealing the growth and etching processes of nanomaterials, and finally concludes with perspectives on the opportunities and challenges associated with GLC‐based research. This review aims to provide a panoramic understanding and up‐to‐date overview of this rapidly evolving field.