Multi-triphenylamine-functionalized dithienylbenzothiadiazoles as hole-transporting non-doped red emitters for efficient simple solution processed pure red organic light-emitting diodes

摘要

To achieve high efficiency solution processed red OLED, a series of new triphenylamine-functionalized dithienylbenzothiadiazoles, namely TB, T3TB and T4TB, as non-doped solution-processed hole-transporting red emitters were synthesized and characterized. Particularly, T3TB having five triphenylamine units substituted on the dithienylbenzothiadiazole core exhibited a good red emission with high T_g amorphous and good film-forming properties. A simple structured non-doped red OLED (ITO/PEDOT:PSS/T3TB(spin coating)/BCP/LiF-Al) with an efficiency (η) of 6.25 cd A~(-1) at 4.1 mA cm~(-2) (PE=5.17 lm W~(-1)), a low turn-on voltage (3.0 V) and a pure red emission (λ_(EL) = 656 nm, CIE (x,y) = 0.67,0.33) was attained.