Blue polymer light-emitting diodes with organic/inorganic hybrid composite as hole transporting layer

Polymer double-layer light-emitting diodes were fabricated with inorganic/organic hybrid composite as hole transporting layer. Two conjugated polymers, poly(9,9-dibutyl)fluorene (PDF) and a dendritic polyfluorene derivative, poly((9,9-dibutyl-2,7-diiodo-9H-fluorene)trisphenylamine) (PDFA) were introduced as light-emitting layer. The former organic double-layer devices showed luminance as high as 833 lm/m2, and the power efficiency reached 0.065 lm/W. The latter showed maximum luminance of 1100 lm/m2 and the quantum efficiency reached 0.104 lm/W. The values were higher than those single-layer devices without inorganic/organic hybrid hole transporting layer (HHTL). The improvement in the electroluminescent properties of these devices was attributed to that the introduction of HHTL enhanced hole injection and balanced the combination of hole and electron injected from anode (ITO) and cathode (Mg:Ag).