Tuning of molecular rectification in donor/acceptor assemblies via supramolecular structures

Tuning of molecular rectification has been demonstrated in donor/acceptor (D/A) assemblies. Electron flow was favorable from donor to acceptor in both D/A and A/D assemblies. A molecular layer of a D/A supramolecule was built via layer-by-layer electrostatic assembly of a monolayer of a donor and a monolayer of an acceptor in sequence. The advantages of D/A assemblies over D-sigma-A molecules as a molecular rectifier have been discussed. The novelty of our approach opened up possibilities for selecting suitable D/A combinations and the separation between the donor and acceptor components in the assembly. In this article, we studied the effect of the substitution of fluorone (as acceptor), which tunes its molecular orbitals, on the rectification properties of the junction. The rectification of the molecular D/A assemblies has also been tuned by changing the spacing between the donor and acceptor moieties.