Development of a Multitimescale Time-Resolved Electron Diffraction Setup: Photoinduced Dynamics of Oxygen Radicals on Graphene Oxide

Abstract

We developed a multitimescale time-resolved electron diffraction setup by electrically synchronizing a nanosecond laser with our table-top picosecond time-resolved electron diffractometer. The setup covers the photoinduced structural dynamics of target materials at timescales ranging from picoseconds to submilliseconds. Using this setup, we sequentially observed the ultraviolet (UV) photoinduced bond dissociation, radical formation, and relaxation dynamics of the oxygen atoms in the epoxy functional group on the basal plane of graphene oxide (GO). The results show that oxygen radicals formed via UV photoexcitation on the basal plane of GO in several tens of picoseconds and then relaxed back to the initial state on the microsecond timescale. The results of first-principles calculations also support the formation of oxygen radicals in the excited state on an early timescale. These results are essential for the further discussion of the reactivities on the basal plane of GO, such as catalytic reactions and antibacterial and antiviral activities. The results also suggest that the multitimescale time-resolved electron diffraction system is a promising tool for laboratory-based molecular dynamics studies of materials and chemical systems.

Graphene oxide-based large-area dynamic covalent interfaces

“…72 Furthermore, they developed a multi-timescale, timeresolved electron diffraction setup and achieved an observation of full structural dynamics of oxygen atoms in epoxy: ultraviolet photoexcitation induced oxygen radical formation in several tens of picoseconds and the relaxation back to the initial state within the microsecond timescale. 73 Conceptually, it might be speculated whether the global position variation of chemical compositions can be realized; that is, whether the long-range migration of chemical compositions is possible. In theory, the local reversible covalent reactions can be spatially connected and occur consecutively just like dominoes, via the combination of DCBs.…”

“…72 Furthermore, they developed a multi-timescale, time-resolved electron diffraction setup and achieved an observation of full structural dynamics of oxygen atoms in epoxy: ultraviolet photoexcitation induced oxygen radical formation in several tens of picoseconds and the relaxation back to the initial state within the microsecond timescale. 73…”