New SFB 677 video podcast online: "Ultrafast Molecular Switches Caught in the Act"
Kiel, 15 December 2015:
Photochemically driven molecular switches are extremely fast: Typically, the switching process takes just 1 picosecond (10‑12 s). To understand the underlying molecular mechanisms, it is necessary therefore to investigate them on the time scale of femtoseconds (10‑15 s). Experimentally, this can be done with modern methods of ultrafast spectroscopy, as applied in our work group. In complementary work, the molecular switching dynamics is simulated theoretically in the group of Professor Bernd Hartke. A new video podcast by the Kiel CRC 677 "Function by Switching" illustrates our approach:
In combined studies of this kind within CRC 677, the photochemical mechanisms of basic switches like azobenzenes and furylfulgides have been analyzed in high details. This, in turn, allows us to systematically improve these molecules, i.e. to develop molecular systems that can be switched from one state to the other more selectively, more rapidly, more efficiently and more robustly. These achievements directly translate to improved applications of the switches, for example in functional materials or as tiny actuators and motors in molecular machines. The video podcast illustrates one of our improvements: An additional bridge between the two phenyl rings of azobenzene improves its switching properties dramatically, by shortening the molecular pathways from one state to the other, and by eliminating other molecular movements that would reduce the switching efficiency. Additionally, the bridge separates the excitation light wavelengths for the forward and backward switching directions.