Comparative study of hole transport in polyspirobifluorene polymers measured by the charge-generation layer time-of-flight technique

Frederic Laquai*, Gerhard Wegner, Chan Im, Heinz Bässler, Susanne Heun

*Corresponding author for this work

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Hole transport in a polyspirobifluorene homopolymer and a statistical polyspirobifluorene-triarylamine copolymer has been studied in detail employing the charge-generation layer time-of-flight (TOF) technique over a wide range of electric fields and temperatures. Both materials exhibit nondispersive TOF signals after injection of a sheet of charge carriers from a thin (10 nm) perylene-diimide charge-carrier generation layer into a relatively thick (d>1 μm) polymer film. Results were analyzed within the framework of the Gaussian disorder model and the charge transport parameters were extracted for both polymers. The zero-field hole mobility of the spirohomopolymer was found to be on the order of 10-6 cm2 V s, whereas the copolymer showed a considerably lower hole mobility of 6× 10-8 cm2 V s. The width of the density of states σ was determined to be 86 meV for the homopolymer and 107 meV for the copolymer. The latter polymer also showed an increased positional disorder due to the statistically incorporated triarylamine units.

Original languageEnglish (US)
Article number023712
JournalJournal of Applied Physics
Issue number2
StatePublished - Jan 15 2006

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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