Recent Advances of Intrinsically Conductive Polymers

Abstract

Intrinsically conductive polymers are a class of exciting materials since they combine the advantages of both metals and plastics. But their application is limited due to the issues related to their electronic properties, stability and processibility. For example, although polyacetylene can have electrical conductivity comparable to metals, it degrades fast in air. Most of the conductive polymers in the conductive state, such as polypyrrole and polythiophene, cannot be dispersed in any solvent and cannot be turned to a melt. It is thus difficult to process them into thin films with good quality, while thin films with good quality are important for many applications. In terms of the materials processing, polyaniline (PANi) and poly(3,4-ethylenedioxythiophene) (PEDOT) have gained great attention. PANi doped with some large cations can be dispersed in some toxic organic solvents, and poly(3,4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS) can be dispersed in water and some polar organic solvents. But the PANi and PEDOT:PSS films prepared from their solutions are usually low. Recently, great progress was made in improving the properties of intrinsically conductive polymers. The conductivity of PEDOT:PSS can be enhanced from 10 −1 S•cm −1 to > 4000 S•cm −1 through the so-called "secondary doping". The high conductivity together with the solution processibility enables the application of conductive polymers in many areas, such as electrodes and thermoelectric conversion. In addition, due to their electrochemical activity, conductive polymers or their composites with inorganic materials can have high capacity of charge storage. Conductive polymers can also be added into the electrodes of batteries, because they can facilitate the charge transport and alleviate the large volume change problem of silicon electrode of batteries. It has been demonstrated that conductive polymers can have important application in many areas, such as transparent electrode, stretchable electrode, neural interfaces, thermoelectric conversion and energy storage system. This article provides a brief review on the enhancement of the electrical conductivity of intrinsically conductive polymers and their application as electrodes and in thermoelectric conversion, supercapacitors and batteries.

Recent progress on PEDOT:PSS based polymer blends and composites for flexible electronics and thermoelectric devices

“…31 There have been some reviews that reported the methods and suggested mechanisms for enhancement of its conductivity. [32][33][34] In addition to its excellent electrical conductivity, its superior transparency (80-95%) in the visible range and satisfactory flexibility make it a good candidate to replace brittle and high cost indium tin oxide (ITO) as a transparent electrode in optoelectronic devices. And several research groups have reviewed its salient properties in optoelectronic devices from different viewpoints of applications such as organic and perovskite solar cells, [35][36][37] photoelectron spectroscopy, 38 organic light-emitting diodes 39 and electrode materials for supercapacitors.…”

MnCo Oxides Supported on Carbon Fibers for High-Performance Supercapacitors

“…Recently, as a promising electrode material of PC, bimetallic manganese cobalt oxides (MnCo) have attracted more and more interest due to their low cost, excellent electrochemical performances and environmentally friendly property [23][24][25][26][27][28][29][30] . The bimetallic oxides have higher rate capability and more excellent capacitive performance than the monometallic oxides [31][32][33][34][35][36] .…”

Enhancement of the Seebeck Coefficient of Organic Thermoelectric Materials via Energy Filtering of Charge Carriers

“…For example, the conductivity of PEDOT:PSS can be enhanced by 3-4 orders of magnitude through a treatment with polar organic solvents like dimethyl sulfoxide (DMSO) or ethylene glycol (EG), acids, co-solvents, solutions, surfactants or ionic liquids. [23][24][25][26][27][28][29][30][31][32][33][34] The conductivity enhancement is ascribed to the removal of some PSSH from PEDOT:PSS and conformational change of the PEDOT chains from the coil to the expanded-coil or linear structure. Although As mentioned above, dedoping can increase the Seebeck coefficient, and secondary doping can enhance the conductivity of TE polymers.…”