Are the Accompanying Cations of Doping Anions Influential in Conducting Organic Polymers? The Case of the Popular PEDOT

Abstract

Conducting organic polymers (COPs) are made of ac onjugated polymer backbone supporting ac ertain degree of oxidation. These positive charges are compensated by the doping anions that are introduced into the polymer synthesis along with their accompanying cations.I nt his work, the influence of these cations on the stoichiometry and physicochemical properties of the resulting COPs have been investigated, something that has previously been overlooked,b ut, as herep roven, is highly relevant. As the doping anion, metallacarborane [Co(C 2 B 9 H 11 ) 2 ] À was chosen, which acts as at histle.T his anion binds to the accompanying cation with ad istinct strength. If the binding strength is weak, the doping anion is more pronet oc ompensate the positivec hargeo ft he polymer,a nd the opposite is also true. Thus, the ability of the dopinga nion to compensate the positive charges of the polymer can be tuned, and this determines the stoichiometry of the polymer.A st he polymer,P EDOT wass tudied, whereas Cs + ,N a + ,K + ,L i + ,a nd H + as cations.N otably,w itht he [Co(C 2 B 9 H 11 ) 2 ] À anions, these cations are grouped into two sets, Cs + and H + in one and Na + ,K + ,a nd Li + in the second, according to the stoichiometry of the COPs:2 :1 EDOT/[Co(C 2 B 9 H 11 ) 2 ] À for Cs + and H + , and 3:1E DOT/[Co(C 2 B 9 H 11 ) 2 ] À for Na + ,K + ,a nd Li + .T he distinct stoichiometries are manifested in the physicochemical properties of the COPs, namely in the electrochemical response, electronic conductivity,i onic conductivity,a nd capacitance.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.

Cation exchange behavior during the redox switching of poly (3,4-ethylenedioxythiophene) films

“…Cations can participate in the processes of the PEDOT film p-doping. This was proven by Toth et al [39], where ion transfer was studied at the polymer film interface with aqueous solution of complex electrolytes containing cations such as Na + , K + , and Ru + and by Fuentes et al [40] for PEDOT films doped with metallacarborane [Co(C 2 B 9 H 11 ) 2 ] − , in the presence of Cs + , Na + , K + , Li + , and H + cations.…”

“…Some of the anions will leave the polymer during reduction, but some can remain trapped in the film. Cations that are strongly bound to the anion can be also introduced in the polymer film during its synthesis [40], thus influencing the conductive polymer the properties, such as its ionic and electronic conductivity, or its electrochemical response. Certain amount of cations can be inserted during reduction, too, in order to neutralize the trapped anions.…”

“…It has been shown that although anion incorporation is the simplest phenomenon in the charge compensation during the oxidation of conductive polymers, the process involves also cation and solvent motion, depending on the deposition conditions, e.g., electrode potential applied during the electrodeposition [33,39,40]. Cations can participate in the processes of the PEDOT film p-doping.…”

“…Schoetz et al showed [42] that the doping of PEDOT film consists of a mixture of Cl − and AlCl 4 − anions. The mixed participation of the electrolyte cations and anions in the charge transfer processes in the PEDOT layer has also been discussed in [20,[38][39][40]. Theoretical approaches describing ion exchange in conductive polymer film during charging processes have been proposed by Vorotyntsev et al in [25].…”

Enhancing cycling stability of tungsten oxide supercapacitor electrodesviaa boron cluster-based molecular cross-linking approach

“…This work further highlights the potential promise of boron cluster-containing materials as unique building blocks for the next generation of energy storage and conversion materials and devices. [47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65] Conflicts of interest Please do not adjust margins There are no conflicts to declare.…”