In a study published in the journal Nature Communications, researchers of Nanomol group, led by the Scientific Director of Unit 6 of NANBIOSIS, Dr. Jaume Veciana have shown that the alignment of the energy levels in molecular bonds based on sel- assembled monolayers can be regulated through only chemical modifications.
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 is where the researchers 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. These are the findings that 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.
Article of reference:
Chemical control over the energy-level alignment in a two-terminal junction. Li Yuan, Carlos Franco, Núria Crivillers, Marta Mas-Torrent, Liang Cao, C.S. Suchand Sangeeth, Concepció Rovira, Jaume Veciana*, Christian A. Nijhuis*. Nature Communications.