Light-driven molecular switches are already used in technical devices such as LCD displays and storage media. Full comprehension of the processes at a molecular scale is required to increase their efficiency, but this knowledge had not been available to date.
By computer simulation studies, a consortium of theoretical chemists and physicists from the Ruhr-University Bochum and King's College London has now managed to reconstruct the exact course of the light-driven molecular changes and gain insight into the switching process. This enables targeted chemical design of light-controllable nanotechnological devices. Dr. Marcus Böckmann, Prof. Dominik Marx (RUB) and Dr. Nikos Doltsinis (King's College) have published their findings in Angewandte Chemie International Edition.
The colour of light causes the molecule to switch over
Chemically modified azobenzene was used for the computer simulation based on the laws of quantum mechanics. The azobenzene molecule can have two forms and vary between them, different coloured light triggering the switching processes.
The researchers carried out a detailed computer simulation study of the switchover processes of the two molecular forms, attaining unprecedented insight into the atomic resolution. Dr. Markus Böckmann explained that it is important that the switching process is fast and highly efficient in all devices in which it is used.
Recent experiments have shown that particular chemical modifications in azobenzene can significantly enhance this process. However, to date the reasons for this improvement have not been understood.
The computer simulation study could explain the experimental results for the first time. The researchers reported that they have been able to establish a clear relationship between the structure and switching properties of the molecule. This is a decisive step for the chemical design of azobenzene-based light-driven nanotechnological devices and thus the development of improved light-controlled materials.
- Marcus Böckmann, Nikos L. Doltsinis, Dominik Marx. Unraveling a Chemically Enhanced Photoswitch: Bridged Azobenzene. Angewandte Chemie, 2010; DOI: 10.1002/ange.200907039
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