Three-dimensional carbazole-based dendrimers: model structures for studying charge transport in organic semiconductor films

Mutkins, Karyn, Chen, Simon S. Y., Pivrikas, Almantas, Aljada, Muhsen, Burn, Paul L., Meredith, Paul and Powell, Ben J. (2013) Three-dimensional carbazole-based dendrimers: model structures for studying charge transport in organic semiconductor films. Polymer Chemistry, 4 4: 916-925. doi:10.1039/c2py20670f

Author Mutkins, Karyn
Chen, Simon S. Y.
Pivrikas, Almantas
Aljada, Muhsen
Burn, Paul L.
Meredith, Paul
Powell, Ben J.
Title Three-dimensional carbazole-based dendrimers: model structures for studying charge transport in organic semiconductor films
Journal name Polymer Chemistry   Check publisher's open access policy
ISSN 1759-9954
Publication date 2013-01
Year available 2012
Sub-type Article (original research)
DOI 10.1039/c2py20670f
Open Access Status Not Open Access
Volume 4
Issue 4
Start page 916
End page 925
Total pages 10
Place of publication Cambridge, United Kingdom
Publisher R S C Publications
Collection year 2013
Language eng
Formatted abstract
We report the synthesis and charge transport properties of a series of three-dimensional dendrimers up to the third generation that have a 9,9′-spirobifluorene core, carbazole-based dendrons and di-n-propylfluorene surface groups. The dendrimers can all be spin-coated to form good quality amorphous films. The charge carrier mobility of the dendrimers was measured by two different methods; in an organic field-effect transistor (OFET) architecture, and by Charge Extraction by Linearly Increasing Voltage (CELIV). In the OFET configuration the first generation dendrimer had a maximum mobility of 4.1 × 10-4 cm2 V-1 s -1 and an ON/OFF ratio of 1.1 × 105. Unexpectedly, in spite of the third generation dendrimer having a volume approximately six times that of the first generation, the mobility was found to decrease by only an order of magnitude. A similar trend in mobility was seen in the CELIV results. Photoluminescence (PL) measurements in solution showed that the first generation dendrimer was comprised of non-interacting chromophores, while the second and third generation dendrimers had substantial intra-dendrimer interchromophore interactions. In the solid-state, PL measurements showed that for the first generation dendrimer there were clear inter-dendrimer interchromophore interactions with little change for the second and third generations. Comparison of the dendrimer molecular volumes in solution and the solid-state showed that in the latter, the dendrimers took up a smaller volume suggesting that there was interdigitation of the dendrons. For the first generation dendrimer the interdigitation leads to trap sites for charge transport, with the small decrease in mobility in moving from the first to the second and third generation being due to the extra intra-dendrimer interchromophore interactions. Model dendritic systems such as these can be used to gain significant insight into the subtly of charge transport phenomena in solution processable macromolecular organic semiconductors, since they offer a level of molecular control that is difficult to achieve with polymers
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes First published on the web: 23 October 2012.

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Mathematics and Physics
Official 2013 Collection
School of Chemistry and Molecular Biosciences
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