Voltage-Tunable Multicolor Electroluminescence from Single-Layer Polymer Blends and Bilayer Polymer Films

摘要

Voltage-tunable orange reversible yellow reversibl green electroluminescence was observed from light-emitting diodes made from binary blends of n-type poly(2,2'-(3,3'-dioctyl-2,2'-bithienylene)-6,6'-bis(4-phenylquinoline)) or poly(4-hexylquinoline) or poly(4-octylquinoline) with p-type poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene). Bilayer poly(p-phenylene vinylene)/poly(9,9-dioctylfluorene) light-emitting diodes had voltage-tunable green reversibl blue colors. A large enhancement in performance was observed in both the blend and bilayer color-tunable light-emitting diodes. The blend devices had a turn-on voltage as low as 5 V, a luminance of up to 1490 cd/m~2, and an external electroluminescence efficiency of up to 0.7%. These results demonstrate that proper choice of electroluminescent polymers with favorable electronic structures can facilitate achievement of efficient multicolor light-emitting diodes from donor/acceptor polymer blends.