Device Stability Enhancement In TADF OLEDs

研究成果: ジャーナルへの寄稿会議記事査読

2 被引用数 (Scopus)

抄録

Organic light-emitting diodes (OLEDs) under constant current operation suffer from a decrease of luminance accompanied by an increase of driving voltage. We report a way to greatly improve the stability of OLEDs having a green emitter exhibiting thermally activated delayed fluorescence (TADF), (4s,6s)-2,4,5,6-tetra(9H-carbazol-9-yl) isophthalonitrile (4CzIPN), by introducing ultrathin (1 to 3 nm) interlayers of 8-hydroxyquinolinato lithium (Liq) between hole-blocking layer and its surrounding emissive and electron-transport layers. Under constant current operation starting at a luminescence of 1,000 cd/m2, the time to reach 90% of initial luminance (LT90) increased eight times, resulting in LT90 = 1,380 hours after insertion of the interlayers. Combining this new concept and mixed host system, LT95 was further extended to 1315 hours that is 16 times of reference device. This is the best value reported for TADF-based OLEDs and is comparable to the operational lifetimes of well-established phosphorescence-based OLEDs. Thermally stimulated current measurements showed that the number of deep charge traps was reduced with the insertion of the ultrathin Liq interlayer, indicating that reducing the number of deep traps is important for improving the operational lifetime and that exciton-polaron annihilation may be a source of the device degradation.

本文言語英語
ページ(範囲)290-293
ページ数4
ジャーナルDigest of Technical Papers - SID International Symposium
47
1
DOI
出版ステータス出版済み - 2016
イベント54th Annual SID Symposium, Seminar, and Exhibition 2016, Display Week 2016 - San Francisco, 米国
継続期間: 5月 22 20165月 27 2016

!!!All Science Journal Classification (ASJC) codes

  • 工学一般

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