Intrachain hole mobility

Prins P, Grozema FC, Schins JM, Patil S, Scherf U, Siebbeles LDA (2006) High intrachain hole mobility on molecular wires of ladder-type poly(p-phenylenes). Phys Rev Lett 96 146601... 

In Fig. 4 the after-pulse growth of the PR-TRMC transients due to positive ion scavenging by different Tt-bond conjugated polymers in oxygen saturated benzene is illustrated. From kinetic fits to the transients, using the known free-ion yield in benzene, the intrachain hole mobility could be determined and the values were found to vary from a low of 0.02 cm /Vs for the polythiophene to a high of 0.74 cm /Vs for the polyfluorene derivative. Mobility values in the... 

Chart 1.8 Chemical structures ofp-phenylene and phenylene-vinylene polymers employed for the determination ofthe intrachain hole mobility [102,103]. 

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... 

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