Direct Evidence for Delocalization of Charge Carriers at the Fermi Level in a Doped Conducting Polymer

Abstract

The infrared absorption spectrum of the polaron charges at the Fermi level EF in a heavily p-doped conducting poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) film has been measured using interferogram-modulated Fourier-transform charge-modulation spectroscopy. The spectrum indicates softer phonons and weaker electron-phonon coupling riding on a strongly redshifted Drude-like electronic transition, different from the population-averaged "bulk" spectrum. This provides direct evidence that the EF holes are sufficiently delocalized even in such disordered materials to reside in an energy continuum (band states) while the rest of the hole population resides in self-localized gap states.

Investigation of the thermoelectric response in conducting polymers doped by solid-state diffusion

“…polymers -polyacetylene [45], polyaniline [46], polythiophenes [47,48,49,50], poly-p-phenylene sulfide [51,52] and recently in PEDOT [53]. Normally, the mobility enhancement at higher energy has been associated with insulator-metal transition via the generation of metallic bands by polarons and bipolarons [54].…”

Giant infrared absorption bands of electrons and holes in conjugated molecules

“…Similarly, early research on holes and electrons in conjugated polymers discovered vibrational absorption by 'IR active' molecular vibrations [5][6][7][8][9] . Extensive research on these 'IRAV' bands and Raman scattering in solid films of polymers and their ions [10][11][12][13][14][15][16][17] produced insight on the natures of the species and fascinating behaviour including possibly large intensities and Fano-like interferences. These are plausibly strong, but absolute intensities were not determined.…”

On the Charge Carrier Time-of-Flight Mobility and the Ordering Effects in the Microcrystalline PEDOT/PSS Complex: a Morphology-Based Simulation Study

“…Biasing voltage 4 V is mainly used; layer thickness 82.3 nm leads to the electric field strength 5.18 10 5 V/cm. Low charge carrier density (see below) and absence of permanent dipoles in the systems results in ohmic regime as shown in (Grell, 2005, Zhuo et al, 2008.…”