Can true space-charge-limited currents be observed in π-conjugated polymers?

The observation of space-charge-limited (SCL) currents in hole conductors requires that the hole density injected at the electrode, pinj, overwhelm the bulk free hole density pf. It also requires that any mobile ion density nion be insignificant. SCL currents are often claimed in amorphous films of...

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Bibliographic Details
Published in:Journal of applied physics 2006-06, Vol.99 (11)
Main Authors: Gregg, Brian A., Gledhill, Sophie E., Scott, Brian
Format: Article
Language:English
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Summary:The observation of space-charge-limited (SCL) currents in hole conductors requires that the hole density injected at the electrode, pinj, overwhelm the bulk free hole density pf. It also requires that any mobile ion density nion be insignificant. SCL currents are often claimed in amorphous films of π-conjugated polymers. However, we estimate pf in poly(p-phenylene-vinylene) derivatives from the conductivities and carrier mobilities as 1017–1019cm−3 and show that even if nion=0, the currents in π-conjugated polymers are often better described as Poole-Frenkel (PF) currents. When nion>0, even the PF model is an oversimplification.
ISSN:0021-8979
1089-7550
DOI:10.1063/1.2201859