title: Single-molecule optomechanical cycle.
abstract: Light-powered molecular machines are conjectured to be essential constituents of future nanoscale devices. As a model for such systems, we have synthesized a polymer of bistable photosensitive azobenzenes. Individual polymers were investigated by single-molecule force spectroscopy in combination with optical excitation in total internal reflection. We were able to optically lengthen and contract individual polymers by switching the azo groups between their trans and cis configurations. The polymer was found to contract against an external force acting along the polymer backbone, thus delivering mechanical work. As a proof of principle, the polymer was operated in a periodic mode, demonstrating for the first time optomechanical energy conversion in a single-molecule device.
authors: Lehrstuhl für Angewandte Physik & Center for Nanoscience, Ludwig-Maximilians Universität, Amalienstrasse 54, 80799 München, Germany.
authors: Thorsten
authors: T
authors: Hugel
authors: Nolan B
authors: NB
authors: Holland
authors: Anna
authors: A
authors: Cattani
authors: Luis
authors: L
authors: Moroder
authors: Markus
authors: M
authors: Seitz
authors: Hermann E
authors: HE
authors: Gaub
mesh_terms: D001391:Azo Compounds / Q000737:chemistry*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004121:Dimethyl Sulfoxide; D008027:Light; D019563:Mechanics; D018625:Microscopy, Atomic Force; D008968:Molecular Conformation; D036103:Nanotechnology; D055095:Optics and Photonics; D010455:Peptides / Q000737:chemistry*; D010777:Photochemistry; D011108:Polymers; D011487:Protein Conformation; D012984:Software; D013057:Spectrum Analysis; D013696:Temperature
chemical_list: D001391:Azo Compounds; D010455:Peptides; D011108:Polymers; C009850:azobenzene; D004121:Dimethyl Sulfoxide