| Popis: |
In this contribution, we demonstrate white organic light-emitting diodes (OLEDs) with a top-emissive layer structure containing a cavity. Two highly efficient phosphorescent emitter materials ((Ir(MDQ) 2 (acac) and Ir(ppy) 3 ) are combined with the stable fluorescent emission system MADN:TBPe in a multilayer hybrid pin-OLED between two highly reflecting metal layers. Different materials for the anode mirror are tested to support the blue components from the arising mircrocavity, in order to optically balance the white emission spectrum and modify the color quality. We enhance the OLED performance by altering the electron blocking material and the transport layer thicknesses. Our devices exhibit improved forward directed radiation, which is usually preferred for applications in lighting industries. We achieve luminous efficacies up to 13.3 lm/W as well as external quantum efficiencies of 5.3% for 1000 cd/m 2 . An optimal p-/ntransport layer ratio permits to reach even 17.9 lm/W and 6.3% at 500 cd/m 2 .The emission shows very good Commission Internationale d'Eclairage chromaticity coordinates (CIE 1931) (e.g. x, y=0.443, 0.413) near the warm white point A and color rendering indices up to 77. |
