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Updated: Aug 11, 2026
Fabrication Procedures and Birefringence Measurements for Designing Magnetically Responsive Lanthanide Ion Chelating Phospholipid Assemblies
Published on: January 3, 2018
Molecular rectification: stabilised alignment of chevron-shaped dyes in hybrid SAM/LB structures in which the
Geoffrey J Ashwell1, Marta Sujka, Andrew Green
1The Nanomaterials Group, Cranfield University, Cranfield MK43 0AL, UK. g.j.ashwell@cranfield.ac.uk
Abstract:
The chevron-shaped dye, N-butyl-2,6-bis-[2-{4-(2-(4-dibutylaminophenyl)-vinyl)-phenyl}-vinyl]-pyridinium iodide, has a hydrophilic apex that is electron-accepting and hydrophobic it-bridged limbs that are electron-donating. It forms non-centrosymmetric monolayers at the air-water interface and when deposited, its LB films exhibit second-harmonic generation and asymmetric current-voltage (I-V) characteristics. However, the behaviour is short lived: molecular reorganisation causes the absorption maximum to shift from ca. 400 to 700 nm with suppression of the SHG and rectification. Long-term stability results when the cationic dye is LB deposited on an anionic surface, for example, a SAM formed via chemisorption of sodium 3-mercapto-1-propanesulfonate on a gold-coated substrate. The hybrid Au/SAM/LB device exhibits asymmetric I-V curves with rectification ratios of ca. 25 at +/- 1 V when investigated by scanning tunnelling spectroscopy and contacted by PtIr probes.
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