Materials Science & Engineering
North Carolina State University
2D Transition Metal Dichalcogenide Materials: Towards Atomic-scale Catalysis and Photonics
Location: EB1 Room 1011
Friday, August 28th 2015 - 11:00 am
Two-dimensional (2D) transition metal dichalcogenide (TMDC) materials such as MoS2, WS2, MoSe2, and WSe2 have emerged as a topical area of physical science and engineering. It is widely believed that these materials bear great potentials to enable new functionalities that cannot be obtained with other material systems. However, the understanding for the fundamental properties of 2D TMDC materials has remained limited, which stands as a major challenge for applying these materials into practical devices.
In this talk, I will present the new fundamental understanding that we have obtained on the catalytic and optical properties of 2D TMDC materials, in particular, atomically thin MoS2 films. Many of the new understanding are unexpected and surprising to some degree. For instance, we find that monolayer MoS2 provides an excellent catalyst for the hydrogen evolution reaction (HER) with remarkable catalytic activities and stability. Our results also suggest that the conventional theory, which believes that only the edge site of MoS2 is catalytic active, is likely wrong. Additionally, we find that the dielectric function of atomically thin MoS2 films is dominated by excitonic effects, instead of the effect of band structures that usually play a dominant role in the dielectric function of conventional materials. Except showing the advance in fundamental understanding, we will show the novel catalytic, photonic, and surface science devices that we have designed by leveraging on the new scientific advance.