Intra-Chain Transport at Short Time Scales

1 Intra-Chain Transport at Short Time Scales 

The ideal systems to test this conjecture are single-crystalline poly-diacetylenes (PDAs), notably perfect PDA chains embedded in a crystalline lattice [15]. Employing the electroreflection method, Weiser and Mbller [136] analyzed the 

A representative example for the information extracted from a TRMC experiment is the work of Prins et al. [141] on the electron and hole dynamics on isolated chains of solution-processable poly(thienylenevinylene) (PTV) derivatives in dilute solution. The mobility of both electrons and holes as well as the kinetics of their bimolecular recombination have been monitored by a 34-GHz microwave field. It was found that at room temperature both electrons and holes have high intrachain mobilities of fi = 0.23 0.04 cm A s and = 0.38 0.02 cm / V s V The electrons become trapped at defects or impurities within 4 ps while no trapping was observed for holes. The essential results are (1) that the trap-free mobilities of electrons and holes are comparable and (2) that the intra-chain hole mobility in PTV is about three orders of magnitude larger than the macroscopic hole mobility measured in PTV devices [142]. This proves that the mobilities inferred from ToF and FET experiments are limited by inter-chain hopping, in addition to possible trapping events. It also confirms the notion that there is no reason why electron and hole mobilities should be principally different. The fact 

Although the above mobilities in isolated chains of conjugated polymers and in solid phases are much larger than values inferred from ToF experiments, in no case do they come close to the value of 1,000 cm /V s expected for a perfect onedimensional 7i-bonded polymer chain. Moreover, they are morphology-sensitive. 

It was straightforward to apply the TRMC technique to study on-chain charge transport to ladder-type poly-phenylene (LPPP) systems because covalent bridging between the phenylene rings planarizes the chain skeleton, eliminates ring torsions, and reduces static disorder. One can conjecture that in these systems intra-chain motion should be mostly limited by static disorder and chain ends. To confirm this 

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