Intrachain charge transport

Prins P, Grozema FC, Schins JM, Savenije TJ, Patil S, Scherf U, Siebbeles LDA (2006) Effect of intermolecular disorder on the intrachain charge transport in ladder-type poly (p-phenylenes). Phys Rev B 73 045204... 

Band Structure Calculations and Experimental Results The spectroscopic properties discussed above are related primarily to intrachain electronic structure. One exception is the stability of gap states (e.g., polarons) versus the three-dimensional interaction effects mentioned in Chapter 11, Section IV.D. Energy and charge transport are, of course, dependent on interchain transfers. So while there are only a few three-dimensional band structure calculations (e.g., for PA [184] and PPV [185]), there are many theoretical calculations concerning infinite perfectly periodic one-dimensinal chains, the effects of local perturbations, and the elementary excitations of these chains solitons, polarons, and bipolarons. Only a few hints of that work will be given here. It has been discussed and reviewed several times (see, e.g., Refs. 186 to 188). 

The UV-Vis-NIR spectra of a PPy-DBSA solution in chloroform changed little with increasing concentration of the extra DBSA (Figure 8.27), indicating that the increase of extra DBSA concentration had no influence upon the electronic structure of PPy-DBSA since extra DBSA restricts the position of PPy-DBSA at the core of the micelle-like structure [68]. Moreover, due to additional doping with extra DBSA at the core of the micelle-like structure, the PPy-DBSA chain requires more extended conformation, which is favorable for intrachain charge transport. 

PPy chain is restricted by steric interference of extra DBSA. Thus an electronic structure favorable to the intrachain charge transport is achieved. 

Type III polymers are of significant interest, since in these materials the metal group may participate in intrachain charge transport. Many examples of this type of polymer have been prepared by chemical polymerization [99], but fewer examples of their synthesis by electropolymerization are known. 

However, one should bear in mind that interaction between the polymer chains and the solution species (counterions, solvent molecules) may influence the electron transport properties of the polymer. In addition, even when assuming intrachain electron transport, this may also influence intrachain electron hopping. In overall charge transport processes during charging/discharging of the polymer film, counterions also participate. Thus these steps may also become rate-determining. 

Aiyar AR, Hong J-I, Reichmanis E (2012) Regioregularity and intrachain ordering impact on the nanostructure and charge transport in two-dimensional assemblies of poly (3-hexylthiophene). Chem Mater 24 2845-2853... 

The following picture of charge transport in semicrystalline P3HT and similar poly thiophenes emerges, as summarized by Lan et al. and shown in Fig. 7 [80]. The fastest transport is intrachain transport along the polymer backbone. For optimal transport, the polymer backbone should be strongly planarized to allow for long... 

The resulting (CH)x exhibits a well defined fiber pattern and provides the opportunity of determining whether intrachain or interchain processes are most efficient for generating photoinduced carriers. Towsand s work on photoexcitation and charge transport in highly oriented Durham polyacetylene showed that there is a factor of 4 favoring interchain vs. intrachain motion. 

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