High efficiency and low voltage p-i-n electrophosphorescent OLEDs with double-doping emission layers
Research output: Contribution to book/conference proceedings/anthology/report › Conference contribution › Contributed › peer-review
Contributors
Abstract
We demonstrate high-efficiency organic light-emitting diodes (OLEDs) by incorporating a double emission layer (D-EML) into p-i-n-type cell architecture. The D-EML comprises two layers with ambipolar transport characteristics, both doped with the green phosphorescent dye tris(phenylpyridine)iridium [Ir(ppy)(3)]. The first EML features a bipolar, but predominantly hole transporting host material, 4,4',4"-tris(N-carbazolyl)-triphenylamine (TCTA), while the second EML is made of an exclusively electron transporting host, e.g. 3-phenyl-4-(1'-naphthyl)-5-phenyl-1,2,4-triazole (TAZ); with a weak hole transport capability arising from hopping between dopant sites. The D-EML system of two bipolar layers leads to an expansion of the exciton generation region. Due to its self-balancing character, it avoids accumulation of charge carriers at any interface. Thus, a power efficiency of approximately 77 lm/W and an external quantum efficiency of 19.3% are achieved at 100 cd/m(2) at an operating voltage of only 2.65V. More importantly, the efficiency decays only weakly with increasing brightness and a power efficiency of 50 lm/W is still obtained even at 4,000 cd/m(2).
Details
Original language | German |
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Title of host publication | Organic Optoelectronics and Photonics III |
Pages | 26-31 |
Number of pages | 6 |
Volume | 5464 |
Publication status | Published - 2004 |
Peer-reviewed | Yes |
Publication series
Series | Proceedings of SPIE - The International Society for Optical Engineering |
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ISSN | 0277-786X |
External IDs
Scopus | 10044298516 |
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Keywords
Keywords
- Doped charge transport layers, Double emission layers, High efficiency, Low operating voltage, P-i-n structure, phosphorescent OLED