High mobility electron-transport material based on 2,5-dibenzthiazolyl thiophene

We report an electron-transport material; 2,5-dibenzthiazolyl thiophene (TBZT) characterized using the photogenerated time-of-flight technique, which shows a weak electric-field-dependent electron mobility, typically of the order of 1.21×10−4cm2∕Vs at 2.5×105V∕cm, two orders of magnitude higher than the Alq3 complex. This enhanced carrier mobility is facilitated by the excited-state configuration of the molecule as verified by the AM1–CI semiempirical calculations in the anionic form. We show the effect of high mobility electron transport on a bilayer electroluminescent device, ITO∕TPD∕ZBZT∕TBZT (10nm)∕Al, using bis [(2-(2′-hydroxylphenyl) benzthiazolate] zinc (II) complex as the emissive layer which resulted in a 25-nm significant shift in the recombination zone and an improved current–voltage characteristics by a factor of two.