| 초록 |
High efficiency green fluorescent organic light-emitting diodes (OLEDs) were advanced by applying a ternary sensitizing host based on exciplex. The sensitizing host was a mixture of a conventional exciplex and an extra host for controlling the non-radiative exciton decay. In the case of the thermally activated delayed fluorescent(TADF) type exciplex host of tris(4-carbazol-9-ylphenyl)amine (TCTA) and (3′-(4,6-diphenyl-1,3,5-triazin-2-yl)-(1,1′-biphenyl)-3-yl)-9-carbazole (CzTrz), the (oxybis(2,1- phenylene))bis(diphenylphosphine oxide) (DPEPO) acted as the extra host to increase the distance of n-type ~ p-type in exciplex host and exciplex ~ exciplex hosts. This mixture increased the photoluminescence quantum yield(PLQY) of the non-doped exciplex from 61.1% to 65.8% and green fluorophore doped exciplex from 60.1% to 69.2%. Additionally, the maximum external quantum efficiency(EQE) of the green fluorescent OLEDs was improved from 11.2% to 13.6% at a DPEPO content of 50%. |
