Reversible Photomechanical Switching of Individual Engineered Molecules at a Metallic Surface

Matthew J. Comstock, Niv Levy, Armen Kirakosian, Jongweon Cho, Frank Lauterwasser, Jessica H. Harvey, David A. Strubbe, Jean M. J. Fréchet, Dirk Trauner, Steven G. Louie, Michael F. Crommie
2007 Physical Review Letters  
We have observed reversible light-induced mechanical switching for a single organic molecule bound to a metal surface. Scanning tunneling microscopy (STM) was used to image the features of an individual azobenzene molecule on Au(111) before and after reversibly cycling its mechanical structure between trans and cis states using light. Azobenzene molecules were engineered to increase their surface photomechanical activity by attaching varying numbers of tert-butyl (TB) ligands ("legs") to the
more » ... benzene phenyl rings. STM images show that increasing the number of TB legs "lifts" the azobenzene molecules from the substrate, thereby increasing molecular photomechanical activity by decreasing molecule-surface coupling.
doi:10.1103/physrevlett.99.038301 pmid:17678335 fatcat:axim4jisujdc3lpcys6wic5nxi