Charge Carrier Mobility Measurements in Nematic Liquid Crystals

Abstract

The nematic liquid crystal is considered as a weak electrolyte. The analysis of the time behaviour of the transient current flowing through the sample allows the estimation of the mean mobility of anions and cations. The electrohydrodynamic flows are avoided thanks to the application of low voltages. For p-octyloxyphenyl p'-pentyloxybenzoate the measured values of mobility are = 0,9 · 10⁻⁶ cm² V⁻¹ s⁻¹ and = 1,3 · 10⁻⁶ cm² V⁻¹ s⁻¹ at 326K. The temperature behaviour of mobility and conductivity is described by identical activation energies: 0.48 eV and 0.16 eV in nematic and isotropic phase respectively.