Dual efficiency enhancement by delayed fluorescence and dipole orientation in high-efficiency fluorescent organic light-emitting diodes
- 19 September 2011
- journal article
- research article
- Published by AIP Publishing in Applied Physics Letters
- Vol. 99 (12), 123303
- https://doi.org/10.1063/1.3637608
Abstract
To explain the origin of extremely high efficiencies of deep-blue fluorescent organic light-emitting diodes(OLEDs) with anisotropic-shapedanthracene derivatives, the enhancements of singlet-exciton generation efficiency and outcoupling efficiency were investigated by transient electroluminescence measurement and variable angle spectroscopic ellipsometry, respectively. Both the delayed fluorescence from singlet excitons generated via triplet-triplet annihilation and the outcoupling enhancement by dipole orientation of emitters were found to contribute to the high external quantum efficiencies of the devices. This dual efficiency enhancement is important for understanding and further improving high-performance fluorescent OLEDs.Keywords
This publication has 22 references indexed in Scilit:
- Increased light outcoupling efficiency in dye-doped small molecule organic light-emitting diodes with horizontally oriented emittersOrganic Electronics, 2011
- Correlation Between Triplet–Triplet Annihilation and Electroluminescence Efficiency in Doped Fluorescent Organic Light‐Emitting DevicesAdvanced Functional Materials, 2010
- Horizontal orientation of linear-shaped organic molecules having bulky substituents in neat and doped vacuum-deposited amorphous filmsOrganic Electronics, 2009
- Characterization of triplet-triplet annihilation in organic light-emitting diodes based on anthracene derivativesJournal of Applied Physics, 2007
- High-efficiency deep blue host for organic light-emitting devicesApplied Physics Letters, 2007
- Delayed electroluminescence in small-molecule-based organic light-emitting diodes: Evidence for triplet-triplet annihilation and recombination-center-mediated light-generation mechanismJournal of Applied Physics, 2005
- Observation of phosphorescence from tris(8-hydroxyquinoline) aluminum thin films using triplet energy transfer from iridium complexesPhysical Review B, 2005
- Anisotropic optical properties and molecular orientation in vacuum-deposited ter(9,9-diarylfluorene)s thin films using spectroscopic ellipsometryJournal of Applied Physics, 2004
- Anthracene derivatives for stable blue-emitting organic electroluminescence devicesApplied Physics Letters, 2002
- Extended molecular design concept of molecular materials for electroluminescence: sublimed–dye films, molecularly doped polymers and polymers with chromophoresPhilosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 1997