26 August 2016 Efficient triplet harvesting of hybrid white organic light-emitting diodes using thermally activated delayed fluorescence green emitter
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Abstract
Hybrid white organic light-emitting diodes (WOLEDs) were fabricated by applying triplet harvesting (TH) using a green thermally activated delayed fluorescence (TADF) emitter. The triplet exciton of the green TADF emitter can be upconverted to its singlet state. The TH involved energy transfer of triplet exciton from a blue fluorescent emitter to a green TADF and red phosphorescent emitters, where they can decay radiatively. In addition, the triplet exciton of the green TADF emitter was energy transferred to its singlet state for a reverse intersystem crossing by green emission. Enhanced hybrid WOLEDs were demonstrated using an efficient green TADF emitter combined with red phosphorescent and blue fluorescent emitters. Hybrid WOLEDs were fabricated with various hole-electron recombination zones as changing blue emitting layer thicknesses. Among these, hybrid WOLEDs showed a maximum external quantum efficiency of 11.23%, luminous efficiency of 29.20  cd/A, and a power efficiency of 26.21  lm/W. Moreover, the WOLED exhibited electroluminescence spectra with Commission International de L’Éclairage chromaticity of (0.38, 0.36) at 1000  cd/m2 and a color rendering index of 82 at a practical brightness of 20,000  cd/m2.
© 2016 Society of Photo-Optical Instrumentation Engineers (SPIE)
Song Eun Lee, Ho Won Lee, Hyun Jung Baek, Tae Jun Yun, Geum Jae Yun, Woo Young Kim, Young Kwan Kim, "Efficient triplet harvesting of hybrid white organic light-emitting diodes using thermally activated delayed fluorescence green emitter," Journal of Photonics for Energy 6(4), 042507 (26 August 2016). https://doi.org/10.1117/1.JPE.6.042507 . Submission:
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