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Title: Tuning electron transport through a single molecular junction by bridge modification

The possibility of controlling electron transport in a single molecular junction represents the ultimate goal of molecular electronics. Here, we report that the modification of bridging group makes it possible to improve the performance and obtain new functions in a single cross-conjugated molecular junction, designed from a recently synthesized bipolar molecule bithiophene naphthalene diimide. Our first principles results show that the bipolar characteristic remains after the molecule was modified and sandwiched between two metal electrodes. Rectifying is the intrinsic characteristic of the molecular junction and its performance can be enhanced by replacing the saturated bridging group with an unsaturated group. A further improvement of the rectifying and a robust negative differential resistance (NDR) behavior can be achieved by the modification of unsaturated bridge. It is revealed that the modification can induce a deviation angle about 4° between the donor and the acceptor π-conjugations, making it possible to enhance the communication between the two π systems. Meanwhile, the low energy frontier orbitals of the junction can move close to the Fermi level and encounter in energy at certain biases, thus a transport channel with a considerable transmission can be formed near the Fermi level only at a narrow bias regime, resultingmore » in the improvement of rectifying and the robust NDR behavior. This finding could be useful for the design of single molecular devices.« less
Authors:
;  [1] ;  [2]
  1. School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu, Sichuan 610054 (China)
  2. Division of Theoretical Chemistry and Biology, School of Biotechnology, KTH, Royal Institute of Technology, S-106 91 Stockholm (Sweden)
Publication Date:
OSTI Identifier:
22306169
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 1; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; ELECTRIC CONDUCTIVITY; ELECTRIC CONTACTS; ELECTRODES; ELECTRONS; FERMI LEVEL; METALS; MODIFICATIONS; MOLECULES; NAPHTHALENE; SEMICONDUCTOR JUNCTIONS; TRANSMISSION