Enhancement of Luminance via Blending F8BT with Tetraphenyldiaminobiphenyl-Containing Hole Transport Polymer

Abstract

We demonstrated polymer light-emitting diodes (PLEDs) based on poly(9,9'-dioctylfluorene-alt-benzothiadiazole) (F8BT) doped with a nonpolyfluorene tetraphenyldiaminobiphenyl-containing hole transport material, poly(N,N'-bis(4-butylphenyl)-N,N'-bis(phenyl) benzidine) (PPB). The devices have a configuration of ITO/PEDOT:PSS/emissive layer/Al. The emissive layers consisted of F8BT blended with PPB at varied weight ratio. The brightness of the blend devices was significantly increased in comparison with pure F8BT. For the 7% PPB blend, the luminance reached 1078 cd/m2 at 47.5 mA (528 mA/cm2), improved by 3 fold. We propose that increased charge carrier injection and transport is responsible for the enhanced electroluminescence (EL) performance. EL spectrum was hardly influenced by blending.