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Charge Tunneling along Short Oligoglycine Chains
Author(s) -
Baghbanzadeh Mostafa,
Bowers Carleen M.,
Rappoport Dmitrij,
Żaba Tomasz,
Gonidec Mathieu,
AlSayah Mohammad H.,
Cyganik Piotr,
AspuruGuzik Alan,
Whitesides George M.
Publication year - 2015
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201507271
Subject(s) - monolayer , self assembled monolayer , quantum tunnelling , chemistry , superexchange , charge (physics) , molecule , chemical physics , density functional theory , atomic orbital , scanning tunneling microscope , molecular physics , crystallography , computational chemistry , nanotechnology , materials science , physics , optoelectronics , ion , electron , organic chemistry , quantum mechanics , biochemistry
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 Au TS /SAM//Ga 2 O 3 /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).