Chemical control over the energy-level alignment in a two-terminal junction

10.1038/ncomms12066Nature Communications71206

Chemical control over the energy-level alignment in a two-terminal junction

The energy-level alignment of molecular transistors can be controlled by external gating to move molecular orbitals with respect to the Fermi levels of the source and drain electrodes. Two-terminal molecular tunnelling junctions, however, lack a gate electrode and suffer from Fermi-level pinning, making it difficult to control the energy-level alignment of the system. Here we report an enhancement of 2 orders of magnitude of the tunnelling current in a two-terminal junction via chemical molecular orbital control, changing chemically the molecular component between a stable radical and its non-radical form without altering the supramolecular structure of the junction. Our findings demonstrate that the energy-level alignment in self-assembled monolayer-based junctions can be regulated by purely chemical modifications, which seems an attractive alternative to control the electrical properties of two-terminal junctions.The National Research Foundation, Prime Minister’s Office, Singapore under its Medium sized centre programme, and for the NRF fellowship to C.A.N., award No. NRF-RF 2010-03, is kindly acknowledged for supporting this research. C.F., N.C., M.M.-T., C.R. and J.V. acknowledge the CSIC funded i-LINK0841project, the EU FP7 program through ACMOL collaborative project (GA n 618082), ERC StG 2012-306826 e-GAMES, CIG (PCIG10-GA-2011-303989) and ITN iSwitch (GA no. 642196), the financial support from the DGI (Spain) (CTQ2013-40480-R), Spanish Ministry of Economy and Competitiveness, through the ‘Severo Ochoa’ Programme for Centres of Excellence in R&D (SEV-2015-0496), the Generalitat de Catalunya (2014SGR-17) and the Networking Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN); N.C. acknowledges the RyC program; C.F. is enroled in the Materials Science PhD program of UAB.Peer reviewe

Chemical control over the energy-level alignment in a two-terminal junction

The energy-level alignment of molecular transistors can be controlled by external gating to move molecular orbitals with respect to the Fermi levels of the source and drain electrodes. Two-terminal molecular tunnelling junctions, however, lack a gate electrode and suffer from Fermi-level pinning, making it difficult to control the energy-level alignment of the system. Here we report an enhancement of 2 orders of magnitude of the tunnelling current in a two-terminal junction via chemical molecular orbital control, changing chemically the molecular component between a stable radical and its non-radical form without altering the supramolecular structure of the junction. Our findings demonstrate that the energy-level alignment in self-assembled monolayer-based junctions can be regulated by purely chemical modifications, which seems an attractive alternative to control the electrical properties of two-terminal junctions.The National Research Foundation, Prime Minister’s Office, Singapore under its Medium sized centre programme, and for the NRF fellowship to C.A.N., award No. NRF-RF 2010-03, is kindly acknowledged for supporting this research. C.F., N.C., M.M.-T., C.R. and J.V. acknowledge the CSIC funded i-LINK0841project, the EU FP7 program through ACMOL collaborative project (GA n 618082), ERC StG 2012-306826 e-GAMES, CIG (PCIG10-GA-2011-303989) and ITN iSwitch (GA no. 642196), the financial support from the DGI (Spain) (CTQ2013-40480-R), Spanish Ministry of Economy and Competitiveness, through the ‘Severo Ochoa’ Programme for Centres of Excellence in R&D (SEV-2015-0496), the Generalitat de Catalunya (2014SGR-17) and the Networking Research Center of Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN); N.C. acknowledges the RyC program; C.F. is enroled in the Materials Science PhD program of UAB.Peer reviewe