Conductivity of Conjugated Polymers

Section 3.3 clearly documents the limitations of a molecular description of electrical conductivity. Nevertheless, the molecular and supramolecular architecture of defect-free oligomers provides an easier access to a description of a much more complex situation in polymers. The conclusion to be drawn is that the intrinsic conductivity of conjugated polymers will be even higher than reached up to now, if synthetic procedures succeed in avoiding structural defects (see Sect. 9). 

The intrinsic conductivity of conjugated polymers leads, in the field of their microwave properties (e.g. 

Recently, a novel method to tune the conductivity of conjugated polymers or conjugated organic compounds has been proposed and demonstrated in our laboratory [13]. The conductivity is tuned by a dynamic process, like an external electric field, while the conductivity is intrinsic and the charge carriers... 

Based on these studies on FETs, one might have a question can the conductivity of conjugated polymer be enhanced by blending it with insulating polymer The... 

Enhanced Conductivity of Conjugated Polymer/lnsulating Polymer Composites at Low Doping Level Interpenetrated Three-Dimensional Interfaces... 

We previously noted that both intrachain and interchain transport of carriers mdst be considered when examining the electronic conductivity of conjugated polymer materials. We now describe a theoretical model recently developed by Pearson and coworkers that can be used to examine the effect of polymer molar mass and polymer orientation on the conductivity behavior of conjugated polymer materials. 

From this state density diagram the theoretical total conductivity aj (cj = Cdc + ffac) and the thermopower coefficient (S) were calculated for the different levels of the band diagram. The variations of a-r with temperature T and frequency v were discussed for various fluences, leading to the distinction of different successive transport mechanisms [255,256]. In particular, the general intrinsic p-type conduction of conjugated polymers was considered to result fi om the localized defect band close to the valence band. 

The imique electrical conductivity of conjugated polymers has been discussed in Chapter 4 and Chapter 6, including blends containing these polymers. The ability of acidic polymers to act as dopants for the conjugated polymers is weU-recognized, with the prime example being PEDOT PSS poly(3,4-ethylenedioxythiophene) (PEDOT) stabilized and doped with poly(styrene sulfonic acid)(PSS) (also discussed in Chapter 4). 

---