Improving the Performance of Polyfluorene-Based Organic Light-Emitting Diodes via End-capping

Abstract

Efficient deep-blue electroluminescence(EL) is obtained via end-capping polyfluorene (PF) homopolymers with hole-transporting moieties (HTMs). Strong evidence that the observed improvement in device performance is related to the end-capper moieties comes from the comparison of two different end-cappers. The HTM does not disturb the liquid-crystal properties of the PF polymer. Using doped polyimide alignment layers, polarized light-emitting diodes (LEDs) with a polarization ratio in excess of twenty at an efficiency of 0.25 cd/A could be realized.