A new method for the determination of electronic mobility in organic materials associated with optoelectronic devices
It is proposed, by way of studies made using tris(8-hydroxyquinoline) aluminium (Alq3) in an ITO/Alq3/Al structure, that dielectric spectroscopy (represented by log ∊'' = f[log ω]) and a determination of I(V) characteristics permit a good estimation of charge mobility (μ). The value of μ determined by this new method was found to be ca. 2 × 10-6 cm2 V-1 s-1, without bias voltage. This method also allows a facile determination of field effects, and it was possible to demonstrate that μ followed a Poole-Frenkel law. In addition, mobilities determined via field effects alone generally led to overestimation of around one order of magnitude for an electric field of around 1 MV cm-1.