Molecular Engineering and Measurements To Test Hypothesized Mechanisms in Single Molecule Conductance Switching

• Published in: Journal of the American Chemical Society Vol. 128; no. 6; pp. 1959 - 1967
• Main Authors: Moore, Amanda M, Dameron, Arrelaine A, Mantooth, Brent A, Smith, Rachel K, Fuchs, Daniel J, Ciszek, Jacob W, Maya, Francisco, Yao, Yuxing, Tour, James M, Weiss, Paul S
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.02.2006
• Subjects: Applied sciences; Atomic and molecular physics; Barrier heights (internal rotation, inversion, rotational isomerism, conformational dynamics); Electronics; Exact sciences and technology; Molecular electronics, nanoelectronics; Molecular properties and interactions with photons; Physics; Properties of molecules and molecular ions; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Phenylene derivative copolymer; Gold; Liquid solid interface; Electronic properties; Conformational dynamics; Acetylene derivative copolymer; Experimental study; Molecular fluctuation; Scanning tunneling microscopy; Conjugated polymer; Molecular electronics; Molecular orientation; Molecular mobility; Transition elements; Monolayers; Crystal faces; Unsaturated polymer; Organic compounds
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja055761m

Six customized phenylene-ethynylene-based oligomers have been studied for their electronic properties using scanning tunneling microscopy to test hypothesized mechanisms of stochastic conductance switching. Previously suggested mechanisms include functional group reduction, functional group rotation, backbone ring rotation, neighboring molecule interactions, bond fluctuations, and hybridization changes. Here, we test these hypotheses experimentally by varying the molecular designs of the switches; the ability of the molecules to switch via each hypothetical mechanism is selectively engineered into or out of each molecule. We conclude that hybridization changes at the molecule−surface interface are responsible for the switching we observe.