Electron-nuclear double-resonance observation of spatial extent of polarons in polythiophene and poly(3-alkylthiophene)

The figure represents the ENDOR spectra of polarons in polythiophene (PT) (upper curve) and those in regioregular poly(3-octyl thiophene) (RR-P3OT) (lower curve). The maximum ENDOR shift is larger in PT, resulting in the smaller polaron extension of 8 thiophene rings in PT than that of 10 thiophene rings in RR-P3AT.