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[2019 OLED KOREA] Unveiled the latest performance of TADF and Hyperfluorescence, the next generation blue light emitting material

CYNORA and Kyulux have unveiled the latest blue TADF performance and blue hyperfluorescence performance at the 2019 OLED KOREA, which is being held at Novotel Hotel in Gangnam from March 6 to 7, 2019.

Andreas Haldi, chief marketing officer at CYNORA, revealed that the color coordinates of the blue TADF emitter developed by them are 0.13, 20% for EQE and 5 hours for LT95 @ 1,200 nit.

He said, CYNORA in developing deep blue TADF in earnest from 2018, and will find green and red TADF after blue TADF development.

“The maximum EQE of blue hyperfluorescence is 26%, the EQE at 1,000 nit is 22% and the lifetime (LT95 @ 750 nit) is 100 hours,” said Junji Adachi, CEO of Kyulux.

Junji Adachi, CEO, also introduced applications using blue hyperfluorescence and emphasized the potential of hyperfluorescence as a next-generation luminous material.

 

[IMID 2018] Can Blue TADF and Hyperfluorescence meet both efficiency and lifetime?

At IMID 2018 in Busan, BEXCO on August 31, Junji Adachi, CEO of Kyulux disclosed the performance of hyperfluorescence, which adds TADF dopant to the existing fluorescent host and dopant.

The color coordinates of the yellow hyperfluorescence revealed by Junji Adachi are (0.49, 0.50), the FWHM (Full Width at Half Maximum) is 76 nm, the EQE is 15.7% on 1000 nit basis, and the LT50 is 62,000 hours by 1000 nit. And the color coordinates of the green hyperfluorescence are (0.28, 0.65), the FWHM (Full Width at Half Maximum) is 31 nm, the EQE is 20.6% on 1000 nit basis, and the LT50 of 1,000 nit is 48,000 hours.

Junji Adachi also revealed the performance of Blue hyperfluorescence, which is currently under development. The maximum emission wavelength of the blue hyperfluorescence is 470 nm, the EQE at 1000 nit is 22%, and the LT50 at 750 nit is 100 hours. In particular, he predicted that the performance of Blue hyperfluorescence would be further improved in the future, saying that it began to improve rapidly in the first half of 2018.

In the following announcement, Dr. Georgios Liaptsis of CYNORA explained about the deep Blue under development, emphasizing that the wavelength should be 460 nm and the CIEy should be within 0.15. He revealed its performance, adding that CYNORA has been carrying out the necessary research to make the lifetime of deep Blue as long as that of sky Blue even with phenomenon that the life span is getting longer as the Blue goes closer to the sky Blue

Fluorescent blue is currently used for the Blue of all OLED applications. Attention is growing whether Blue TADF or Blue Fluorescence can be commercialized to realize better efficiency and lifetime than existing fluorescent blue.

Next-generation emitting materials, development is under way

At the 4th OLED KOREA CONFERENCE, Kyulux and CYNORA, the leaders in the development of next generation emitting materials, announced the results of research and future development directions.

Junji Adachi, CEO of Kyulux, said, “We are developing Hyperfluorescence in the form of adding a TADF dopant to the existing fluorescent host and dopant.” He also emphasized that the emission FWHM (full width at half maximum) of Hyperfluorescence is about 35% of that of TADF, and the luminance is about twice as high, and this material can solve the drawbacks of TADF (wide FWHM and low luminance) at the same time.

The latest Hyperfluorescence, which Jundi Arachi introduced, has efficiencies of red 28 cd /A, yellow 43 cd/A, green 81 cd / A, and life span is 10,000 hours, 62,000 hours, and 48,000 hours based on LT50 (1000nit) respectively. The color coordinates are red (0.64, 0.36), yellow (0.46, 0.52), and green (0.28, 0.65).

Andreas Haldi, CYNORA’s Chief Marketing Officer of CYNORA, said that the blue TADF emitter developed by CYNORA now has a color coordinate of 0.16, EQE of 24% and 10-hour lifetime (LT97 @ 700nit).

The performance is more than twice as efficient as the blue material currently used in OLEDs, and the color coordinates (0.10) are similar but the lifespan is short. He added that the Blue TADF emitter is scheduled to be developed within 2018 and will be available for mass production in 2019.

He also mentioned that the manufacturing cost is reduced and the power consumption is reduced, thereby minimizing battery consumption if blue TADF emitters with high efficiency are used instead of conventional low-efficiency blue materials. At the same time, it is expected to be able to improve the resolution of OLEDs and be applied to large-scale vacuum processing lines of major panel makers.
According to CYNORA, next step is to develop green TADF emitters (2019) and red emitters (2020) after finishing the development of blue TADF emitters (2018). Thus, it might be completed ‘RGB TADF emitter development’ by 2020.

The 4th Generation Emitting Material, Hyperfluorescence

Thermally activated delayed fluorescence(TADF), still under development to complement OLED emitting materials insufficient as both fluorescence and phosphorescent materials, takes time to be commercialized at the present stage. Even Kyulux considered the most advanced company in terms of TADF technology hasn’t yet to commercialized TADF dopant suitable for display.

Adachi, CTO of Kyulux said the unprepared TADF host material is an obstacle to the commercialization of TADF, so the full width at half maximum of emitting peak is too wide to be applied to display. To solve this problem, the 4th generation hyperfluorescence is under development to commercialize the TADF material.

<Kyulux CTO Adachi>

Hyperfluorescence aims at having the effect of a phosphorescent material by adding TADF dopant to existing fluorescence host and dopant.

<Hyperfluorescence Effect>

This effect has a structure that can solve both the full width at half maximum of TADF and the low brightness of fluorescence materials as seen in the above figure, Adachi emphasized.

<Hyperfluorescence vs General fluorescence>

As seen in the above photo, Kyulux’s OLED made of general green fluorescence material and OLED made of hyperfluorescence by adding TADF to this material have a distinct difference on the same substrate.

Kyulux’s goal is to commercialize hyper fluorescence by 2017. Its target is PMOLED.