Massive polarons in large-energy-gap polymers

We present evidence for the existence of defect states with large mass and low mobility in the conducting polymer polyaniline. This large-energy-gap polymer has been shown to have properties significantly different from many other conducting polymers. Photoinduced infrared absorption studies presented here are consistent with the photogeneration of charged polarons. Analysis within the amplitude mode (Peierls) formalism indicates that these polarons are massive ($M_{\mathrm{pol}\mathrm{\sim }60m_e}$), while use of a bond-order or Holstein polaron formalism leads to even larger estimates of $M_{\mathrm{pol}}$.