Highly efficient fluorescence/phosphorescence hybrid white organic light-emitting devices based on a bipolar blue emitter to precisely control charges and excitons
Hybrid white organic light-emitting diodes (WOLEDs) combining blue fluorophores and green/red (or yellow) phosphors are still preferred for OLED production applications due to their advantages of good stability and high efficiency. One major challenge is to have a suitable blue fluorophore material...
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Published in | Journal of materials chemistry. C, Materials for optical and electronic devices Vol. 8; no. 22; pp. 7543 - 7551 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Cambridge
Royal Society of Chemistry
14.06.2020
|
Subjects | |
Online Access | Get full text |
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Summary: | Hybrid white organic light-emitting diodes (WOLEDs) combining blue fluorophores and green/red (or yellow) phosphors are still preferred for OLED production applications due to their advantages of good stability and high efficiency. One major challenge is to have a suitable blue fluorophore material to fully utilize the electrically generated excitons for fluorophore and phosphor emitters. Here, we employed an efficient blue fluorophore (
PBI-PPI-TPA
) with a high triplet energy of 2.48 eV as the blue emitter as well as the host for phosphors, whereby a series of highly efficient hybrid WOLEDs were successfully achieved. The two-color (BO) WOLEDs exhibited a maximum forward-viewing EQE/PE of up to 23.6%/77.8 lm W
−1
, and retained 20.0%/49.5 lm W
−1
at 1000 cd m
−2
, thus exhibiting high-efficiency and low-efficiency roll-off. Furthermore, three-color (BYR) hybrid WOLEDs were also fabricated by adopting blue-yellow-red cascade energy transfer to ensure that all the excitons could be effectively utilized for the white emission. The resulting devices achieved a peak EQE/PE of 21.5%/53.2 lm W
−1
, retained 17.2%/26.8 lm W
−1
at 1000 cd m
−2
, and the color rendering index (CRI) was doubled with respect to the two-color WOLEDs, showing a good trade-off between the efficiency and CRI. All these results are among the best reported for hybrid WOLEDs.
Highly efficient fluorescence/phosphorescence hybrid WOLEDs have been realized by employing a new efficient blue fluorescent material. |
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Bibliography: | 10.1039/d0tc01549k Electronic supplementary information (ESI) available. See DOI |
ISSN: | 2050-7526 2050-7534 |
DOI: | 10.1039/d0tc01549k |