Reversible photomechanical switching of individual engineered molecules at a metallic surface.
We have observed reversible light-induced mechanical switching for individual organic molecules bound to a metal surface. Scanning tunneling microscopy (STM) was used to image the features of individual azobenzene molecules on Au(111) before and after reversibly cycling their 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 azobenzene 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.
Department of Physics, University of California at Berkeley, Berkeley, California 94720-7300, USA.
Matthew J
MJ
Comstock
Niv
N
Levy
Armen
A
Kirakosian
Jongweon
J
Cho
Frank
F
Lauterwasser
Jessica H
JH
Harvey
David A
DA
Strubbe
Jean M J
JM
Fréchet
Dirk
D
Trauner
Steven G
SG
Louie
Michael F
MF
Crommie