Conductivity Enhancement of PEDOT-PSS

The conductivity of a PEDOT-PSS film can be enhanced by more than 2 orders of magnitude by the addition of polar group containing compounds like ethylene glycol, into an aqueous solution of PEDOT-PSS. The additive induces a conformational change in the PEDOT chains of the PEDOT-PSS film. 

Both coil and linear or expanded-coil conformations exist in untreated PEDOT-PSS films, whereas the linear or expanded-coil conformation becomes dominant in high-conductivity PEDOT-PSS films. This conformational change results in an increase in the intrachain and interchain charge carrier mobility, so the conductivity is enhanced.  

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