■ Title: Aberration-corrected liquid electron microscopy of colloidal and energy materials
■ Speaker: Prof. Jong Min Yuk (MSE KAIST)
■ Date and time: 29th of August (Tue) 16:00
■ Venue: KAIST Applied Engineering B/D(W1), Multimedia Lecture Hall (1st Floor)
■ Abstract : Liquid phase transmission electron microscopy (TEM) has solved many questions in biochemistry, materials science, environmental science, and catalysis. Such observations could greatly benefit from high-resolution offered by aberration-corrected TEMs. However the relatively thick SiN windows necessary to encapsulate the liquid under vacuum and even the liquid trapped between the windows degrades the TEM resolution and signal-to-noise ratio. Thus, most of critical events are still vague due to the lack of ability to study specimen in liquid with atomic resolution. Here, we introduce a new type of liquid cell using graphene sheets to encase colloidal growth solution for in-situ high-resolution TEM (HR-TEM) imaging. The flexibility, mechanical strength and impermeability of graphene allow for the solution to remain liquid within the TEM vacuum while Pt nanoparticles grow and combine under the influence of the electron beam. We demonstrate in-situ observations of the growth, dynamics, and three-dimensional structures of individual colloidal nanocrystals by using graphene liquid cell TEM. I further show in-situ HR-TEM of lithiation process for diverse anode materials, which are not achievable with any other current methods.