High efficiency blue phosphorescent organic light-emitting diode based on blend of hole- and electron-transporting materials as a co-host
- 21 May 2012
- journal article
- research article
- Published by AIP Publishing in Applied Physics Letters
- Vol. 100 (21), 213301
- https://doi.org/10.1063/1.4720512
Abstract
Highly efficient blue phosphorescent organic light-emitting diodes (PHOLEDs) were achieved by blending the same hole- and electron-transporting layer materials in device as the host in the emissive layer. The design of this kind of device structure not only decreases the amount of used organic materials but also greatly reduces the structural heterogeneities and effectively facilitates the charge injection into the emissive layer. The resulting blue PHOLEDs exhibit higher electroluminescent efficiency. The maximum external quantum efficiency and power efficiency reach 20.4% and 55.4 lm W−1, respectively, yet keep 19.5% and 49.9 lm W−1, 18.3% and 40.9 lm W−1, respectively, at a luminance of 100 and 1000 cd m−2, showing a low efficiency roll-off property. The mechanism studies fully demonstrate that the bipolar co-host system extends the lifetime of excitons, broadens the recombination zone, and improves the charge carrier injection and transport balance, which are of greatly critical to get the improved efficiency and efficiency roll-off at high luminance in the blue PHOLEDs.Keywords
This publication has 14 references indexed in Scilit:
- Feeling blue? Blue phosphors for OLEDsMaterials Today, 2011
- Stable efficiency roll-off in blue phosphorescent organic light-emitting diodes by host layer engineeringOrganic Electronics, 2009
- Enhanced efficiency and reduced roll-off in blue and white phosphorescent organic light-emitting diodes with a mixed host structureApplied Physics Letters, 2009
- Suppression of efficiency roll off in blue phosphorescent organic light-emitting devices using double emission layers with additional carrier-transporting materialApplied Physics Letters, 2009
- Pyridine‐Containing Triphenylbenzene Derivatives with High Electron Mobility for Highly Efficient Phosphorescent OLEDsAdvanced Materials, 2008
- Effects of interlayers on phosphorescent blue organic light-emitting diodesApplied Physics Letters, 2008
- Influence of doping profile on the efficiency of blue phosphorescent organic light-emitting diodesApplied Physics Letters, 2008
- Triplet-exciton quenching in organic phosphorescent light-emitting diodes with Ir-based emittersPhysical Review B, 2007
- High-efficiency and low-voltage p-i-n electrophosphorescent organic light-emitting diodes with double-emission layersApplied Physics Letters, 2004
- Endothermic energy transfer: A mechanism for generating very efficient high-energy phosphorescent emission in organic materialsApplied Physics Letters, 2001