Drift Mobility of Positive Ions in Nematic MBBA at Low Electric Field

Abstract

The transport of positive ions in p-methoxybenzylidene-p-n-butylaniline (MBBA) is studied using a photoconductor of amorphous selenium layer as an injector of holes. Experimental results show that the characteristic distance over which injected holes are thermalized to form ions varies in the range of 202 Å to 234 Å depending on temperature, and that the drift mobility of these ions, which increases from 6.0×10-6 cm2/V·sec to 9.4×10-6 cm2/V·sec within nematic temperature, obeys Walden's rule exactly, and their Stokes' radius is close to the effective radius of MBBA molecules. It is suggested that their transient currents in nematic MBBA are carried by the ions of MBBA and their dissociated molecules.