Charge transport in a mixed ionically/electronically conducting, cationic, polyacetylene ionomer between ion-blocking...

Area of Science:

• Materials Science
• Electrochemistry
• Polymer Science

Background:

• Conjugated ionomers offer unique mixed ionic-electronic conductivity.
• Understanding charge transport mechanisms is crucial for developing advanced electronic devices.

Purpose of the Study:

• To elucidate the electrical transport mechanisms in a cationic polyacetylene-based conjugated ionomer.
• To differentiate between unipolar and bipolar transport regimes based on applied voltage.

Main Methods:

• Fabrication of a device with the ionomer sandwiched between gold electrodes.
• Analysis of steady-state current and transient decay under short-circuit and open-circuit conditions.
• Modeling of doping and ionic double-layer charging effects.

Main Results:

• Unipolar diffusive hole transport observed below 1.4 V, transitioning to bipolar migratory transport above 1.4 V.
• A non-Faradaic doping model explains low-voltage behavior; disproportionation drives high-voltage transport.
• Power-law decay analysis and open-circuit voltage decay kinetics confirm transport mechanisms.

Conclusions:

• The ionomer exhibits voltage-dependent charge transport, crucial for its application in electronic devices.
• Hole and electron mobilities are estimated to be in the range of 10^-7 to 10^-6 cm^2 V^-1 s^-1.
• The study provides insights into the fundamental electrical properties of conjugated ionomers for future device engineering.