Improvement of the EL efficiency of the inorganic-organic light-emitting diodes by Rubrene-doping

We evaluated the doping effect on the electroluminescence (EL) efficiency of organic light emitting diodes (OLEDs) in which the active layers consist of inorganic-organic hybrid materials fabricated by sol-gel method. The hybrid materials are SiO₂ containing an organic emissive material, whose EL efficeincy was very low due to the large resistance of SiO₂. Thus, another organic emissive material, Rubrene was doped in the hybrid materials to improve the concentration quenching. As a result, the EL efficiency became about 10 times larger than that without Rubrene-doping. This can be attributed to the energy transfer from the original emissive material to Rubrene.