Conducting Redox Polymers with non-Activated Charge Transport Properties
(English)Manuscript (preprint) (Other academic)
Intrinsic electronic conductivity is the crucial characteristic that distinguishes conducting polymers from most otherorganic materials. The conduction mechanism is structure dependent and the charge transfer character ranges from metallic to temperature-activated hopping as a function of the level of order. Introduction of covalently bound redox active pendant groups toconducting polymers, forming conducting redox polymers (CRPs), introduces additional functionality to conducting polymers butthe effect of the pendant groups on the polymer structure and on the mechanism of charge transport is largely unknown. In thisreport we show that non-activated charge transport can be achieved in terephthalate-functionalized CRPs and we correlate the lowactivation barriers involved with a relatively high degree of polymer order. The charge transport properties were investigated bytemperature dependent conductance measurements performed in situ during electrochemical redox conversion. The resulting temperature dependence showed a transition from a temperature-activated regime to a residual scattering regime, the latter being associated with an apparent negative activation barrier for charge transport indicating low electron transfer reorganization-energies.Activation barriers derived from spectroscopic measurements suggest much higher activation barriers than the temperature dependent conductance data indicate which is rationalized by electron transport through interconnected crystal domains in a predominantamorphous polymer matrix. The finding that non-activated charge transport can be accomplished in CRP materials suggests thatmetallic conductivities can be achieved also for conducting polymers with redox active pendant groups.
IdentifiersURN: urn:nbn:se:uu:diva-304625OAI: oai:DiVA.org:uu-304625DiVA: diva2:1033253