High efficient white emitting devices based on microcavity blue phosphorescent OLEDs with down-conversion phosphors

摘要

There are several approaches to generate white light from organic light emitting diodes (OLEDs). One approach is to use blue emitting OLEDs in conjunction with down-conversion phosphors. This approach requires highly efficient saturated blue emitters to provide efficient excitation for the phosphors. For blue phosphorescent emitters such as FIrpic, the emission spectrum contains too much green light and it does not excite the phosphors efficiently. In order to enhance the blue excitation for the down-conversion phosphors, we incorporated the microcavity structure and demonstrated highly efficiency white OLEDs. We previously demonstrated high efficient microcavity blue phosphorescent OLEDs (PHOLEDs) with power efficiency of 41 lm/W. With down-conversion phosphors incorporated in the blue micro-cavity PHOLEDs, a maximum luminous efficiency of 99 lm/W for the resulting white emitting device with a color rendering index (CRT) of 83 was achieved.