Energetic Disorder in Doped P3HT: A Crucial Factor in Overcoming Coulomb Binding for Free Charge Generation

Doping of conjugated polymers, which offers precise control over energy levels and electrical conductivity, has faced setbacks because of its low doping efficiency. The majority of generated charge carriers become bound to dopant counterions through Coulomb interaction, leaving only a small fraction of free charges. Although the inherent energetic disorder in polymers may reduce the theoretically predicted Coulomb potential barrier and facilitate the release of bound charges to become mobile, this hypothesis has not been thoroughly quantified. In the present study, we investigate how the energetic disorder of conjugated polymers influences the release of free charges by reducing the activation energy, thus quantitatively assessing the effect of disorder on doping efficiency. Specifically, we examine the relationship between energetic disorder resulting from modifications of the crystalli…