Charge Tunneling along Short Oligoglycine Chains |
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| Authors: | Dr Dmitrij Rappoport Tomasz Żaba Dr Mathieu Gonidec Prof Dr Piotr Cyganik Prof Dr Alan Aspuru‐Guzik Prof Dr George M Whitesides |
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| Institution: | 1. Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford St. Cambridge, MA 02138 (USA);2. Smoluchowski Institute of Physics, Jagiellonian University, ?ojasiewicza 11, 30‐348 Krakow (Poland);3. Department of Molecular Nanoscience and Organic Materials, Institut de Ciència de Materials de Barcelona (ICMAB‐CSIC/CIBER‐BBN), Cerdanyola del Vallès, 08193, Barcelona (Spain);4. Kavli Institute for Bionano Science and Technology, Harvard University, 29 Oxford Street, Cambridge, MA 02138 (USA);5. Wyss Institute of Biologically Inspired Engineering, Harvard University, 60 Oxford St. Cambridge, MA 02138 (USA) |
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| Abstract: | This work examines charge transport (CT) through self‐assembled monolayers (SAMs) of oligoglycines having an N‐terminal cysteine group that anchors the molecule to a gold substrate, and demonstrate that CT is rapid (relative to SAMs of n‐alkanethiolates). Comparisons of rates of charge transport‐using junctions with the structure AuTS/SAM//Ga2O3/EGaIn (across these SAMs of oligoglycines, and across SAMs of a number of structurally and electronically related molecules) established that rates of charge tunneling along SAMs of oligoglycines are comparable to that along SAMs of oligophenyl groups (of comparable length). The mechanism of tunneling in oligoglycines is compatible with superexchange, and involves interactions among high‐energy occupied orbitals in multiple, consecutive amide bonds, which may by separated by one to three methylene groups. This mechanistic conclusion is supported by density functional theory (DFT). |
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| Keywords: | biological conduction density functional theory oligopeptides organic electronics superexchange tunneling |
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