Electrical molecular switch addressed by chemical stimuli.

H Audi,Z Chen,H Klein,O Siri,A Heynderickx,Y Viero,C Krzeminski,D Guérin,N Alwhaibi,C J Lambert,F Xiao,S Lenfant,I M Grace,D Vuillaume,M Iazykov

doi:10.1039/d0nr02461a

Abstract

We demonstrate that the conductance switching of benzo-bis(imidazole) molecules upon protonation depends on the lateral functional groups. The protonated H-substituted molecule shows a higher conductance than the neutral one (Gpro > Gneu), while the opposite (Gneu > Gpro) is observed for a molecule laterally functionalized by amino-phenyl groups. These results are demonstrated at various scale lengths: self-assembled monolayers, tiny nanodot-molecule junctions and single molecules. From ab initio theoretical calculations, we conclude that for the H-substituted molecule, the result Gpro > Gneu is correctly explained by a reduction of the LUMO-HOMO gap, while for the amino-phenyl functionnalized molecule, the result Gneu > Gpro is consistent with a shift of the HOMO, which reduces the density of states at the Fermi energy.

Highlights

Molecular electronic exploits the rich variety of organic molecules to create custom-designed molecular devices for applications in future electronics
The molecular conductances were measured at 3 scale lengths : selfassembled monolayers (SAM) on flat Au surface, about hundred molecules grafted on Au nanodots (NMJ : nanodot molecule junction) and single molecule by mechanically controlled break junction (MCBJ)
XPS measurements show that the SAMs of molecules A and B are well formed on the Au surfaces

Summary

Introduction

Molecular electronic exploits the rich variety of organic molecules to create custom-designed molecular devices for applications in future electronics. Current histograms and single molecule conductance are extracted from these measurements as reported in Ref. 56 and detailed in the supporting information.

Results

Conclusion