Mechanism of charge transport in discotic liquid crystals
1995; American Physical Society; Volume: 52; Issue: 18 Linguagem: Inglês
10.1103/physrevb.52.13274
ISSN1095-3795
AutoresN. Boden, Richard J. Bushby, J. Clements, B. Movaghar, K. J. Donovan, Theo Kreouzis,
Tópico(s)Material Dynamics and Properties
ResumoA comparative study is reported of transient photoconductivity and ac conductivity in the liquid-crystalline columnar hexagonal (${\mathit{D}}_{\mathit{h}}$) phase of pure and p-doped hexakis(n-hexyloxy)triphenylene. In both materials, charge-carrier transport is dispersive, and the measured carrier mobilities along the direction of the molecular columns are very similar, ${\mathrm{\ensuremath{\mu}}}_{\mathrm{\ensuremath{\parallel}}}$\ensuremath{\sim}1\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}4}$ ${\mathrm{cm}}^{2}$ ${\mathrm{V}}^{\mathrm{\ensuremath{-}}1}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$. The dispersion arises from the intrinsic liquidlike disorder in the face-to-face packing of the triphenylene rings within the columns. Charge transport is found to be highly anisotropic (${\mathrm{\ensuremath{\mu}}}_{\mathrm{\ensuremath{\parallel}}}$/${\mathrm{\ensuremath{\mu}}}_{\mathrm{\ensuremath{\perp}}}$\ensuremath{\sim}${10}^{3}$). These results are discussed in terms of possible mechanisms for carrier transport in discotic liquid crystals.
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