A bottom-up electrochemical process for fabricating conjugated ultrathin layers with tailored switchable properties is developed. Ultrathin layers of covalently grafted oligo(bisthienylbenzene) (oligo(BTB)) are used as switchable organic electrodes, and 3,4-ethylenedioxythiophene (EDOT) is oxidized on this layer. Adding only a few (less than 3) nanometers of EDOT moieties (5 to 6 units ) completely changes the switching properties of the layer without changing the surface concentration of the electroactive species. A range of new materials with tunable interfacial properties is created. They consist of oligo(BTB)-oligo(EDOT) diblock oligomers of various relative lengths covalently grafted onto the underlying electrode. These films retain reversible redox on/off switching and their switching potential can be finely tuned between +0.6 and -0.3 V/SCE while the overall thickness remains below 11 nm.
Bibliographical noteFunding Information:
This work was supported by the CNRS, the University Paris Diderot (Paris, France) and by a Ph.D. grant from the University of Science and Technology of Hanoi and a Grant no. 15-CE09-0001-01 from Agence Nationale de la Recherche (ANR)
- Bottom-up approach
- Diazonium grafting
- Molecular electronics
- Ultrathin film
- π-conjugated material