1, Hummingbird Scientific, Lacey, Washington, United States
3, Electrical and System Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States
Recent advances in liquid cell transmission electron microscopy (TEM) have enabled the study of reactions in liquid-solid interface at high spatial resolution in real-time environment. The capability to apply stimuli such as electrical, heating and electrochemical measurements has already started to provide new insights on the dynamics and structural changes during nanoparticles synthesis1, lithium charge and discharge2, crystal growth3 and metal corrosion4. The further ability to introduce light within the confined liquid environment of TEM strengthens the capability by allowing the study of light interaction in materials during reaction at solid-liquid interface, thus enabling photoelectrochemistry in TEM. The study of hydrogen generation via photoelectrochemical method5 is one relevant application that can benefit from this technique and can provide fuel for energy storage solution in a clean and environmental friendly manner. However, the atomic scale mechanisms of the photocatalysts that facilitate the water splitting for efficient hydrogen generation are currently poorly understood. Further understanding of the role of various photocatalysts and the physics governing the active hydrogen evolution sites will allow for better and efficient design of photoelectrochemical devices. Here, we present the development of a unique in-situ liquid TEM holder with photo-capable light source to study photocatalytic reactions in real time at nanometer length scales. Using some of the model materials such as Au nanoprisms and MoS2 flakes, we will present the correlation of I-V characteristics with water splitting and simultaneous structural changes at the catalytically active sites. For accurate quantitative information and reliability of materials interface in liquid, we will also present strategies to deposit materials of interests in the desired electrodes of liquid cell chips by using an inkjet materials printer. The availability and utilization of photo stimuli in liquid cell TEM can provide important fundamental insights into the understanding of several other photoelectrochemical systems.
1 Tan et al., J. Am. Chem. Soc., 2018, 140 (37), 11680-11685
2 Lim et al., Science, 2016, 353 (6299), 566-571
3 Nielsen et al., Science, 2014, 345 (6201), 1158-1162
4 Chee et al., Micros. Microanal., 2014, 20 (2), 462-468
5 Maeda, K and Domen, K., J. Phys. Chem. Lett., 2010, 1(18), 2655-2661