Approaching the Frontier Between Fiber Devices and Single Molecule Devices in Redox Gated Junction

Abstract

Charge transport in two conducting polymer poly(bithiophene) (PBT) and poly(ethylenedioxythiophene) (PEDOT) nanojunctions was investigated using two microelectrodes, separated by micrometric gap. Such junctions are redox gated and exhibit conductance switching between low and high resistance states at potential of 1 and 0V respectively. Devices with conductance between 100 nS-500 nS in the oxidized state were easily obtained, indicating control of the charge transport within the whole micrometric gap by a limited number of wires (less than 100 oligomeric strands). I/V characteristics and steady state conductance measurements, for various gate potential, indicates that on/off ratios measured can be as high as 1000 despite the small number of strands controlling the charge transport properties of the devices. Finally, we show that generating nano-junctions whose smallest diameter is below 4 nm on a length close to the size of a polaron, or its localization length, makes it possible to reach the frontier between fiber devices and single molecule devices.

Plasmon-Induced Conductance Switching of an Electroactive Conjugated Polymer Nanojunction

“…Electronic Properties of PEDOT Junctions. The SECM setup includes four electrodes immersed in an acetonitrile solution containing EDOT (monomer) and the salt TBAPF 6 and allows the in situ fabrication of PEDOT nanowires whose elaboration has been described in previous work 41 and has been recalled above. This electrochemical setup, also known as an electrochemical transistor, 42 works as a field-effect transistor with the PEDOT junction as the channel and the tip electrode and the substrate AuNPs@ITO as the source (S) and the drain (D), respectively.…”

From active plasmonic devices to plasmonic molecular electronics

“…The detailed procedures used to create the AuNP substrate and the PEDOT nanowires have been described elsewhere. 60,99,100 Indeed, polymer strands, maintained electrochemically in their oxidized, conducting state, reversibly switch to their insulating state upon irradiation by visible-wavelength light. A sharp decrease in the conductance results ( Fig.…”

Electrochemical techniques for investigating redox active macromolecules

“…SECM in a dual microelectrode setup was also employed to study the charge transport in conducting polymers poly(bithiophene) and poly(ethylenedioxythiophene) nanojunctions [90].…”