High‐Efficiency Polymer Light‐Emitting Diodes with Stable Saturated Red Emission: Use of Carbazole‐Based Copolymer Blends in a Poly(<i>p</i>‐phenylenevinylene) Derivative

Abstract

High‐efficiency red emission is a prerequisite for full‐color display applications of light‐emitting diodes. The devices reported here—with stable external quantum efficiency up to 3.8 (photons/electron)‐%—have a light‐emitting layer consisting of a blend of a novel carbazole‐based copolymer (see Figure) in MEHPPV, a more conventional conjugated polymer, as host.