Tuning electron transport through a single molecular junction by bridge modification
2014 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 116, no 1, 013701- p.Article in journal (Refereed) Published
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 degrees between the donor and the acceptor pi-conjugations, making it possible to enhance the communication between the two pi 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, resulting in the improvement of rectifying and the robust NDR behavior. This finding could be useful for the design of single molecular devices.
Place, publisher, year, edition, pages
2014. Vol. 116, no 1, 013701- p.
Negative Differential Resistance, Cross-Conjugated Molecules, Self-Assembled Monolayers, Quantum Interference, Charge-Transport, Bipolar Molecule, Rectification, Conductance, Devices, Systems
Other Physics Topics
IdentifiersURN: urn:nbn:se:kth:diva-149508DOI: 10.1063/1.4885878ISI: 000339621400028ScopusID: 2-s2.0-84904119668OAI: oai:DiVA.org:kth-149508DiVA: diva2:739936
FunderSwedish Research Council
QC 201501122014-08-222014-08-222015-01-12Bibliographically approved