TADF OLED emitters, or Thermally Activated Delayed Fluorescence, is a relatively new class of OLED emitter materials that promise efficient and long-lifetime performance without any heavy metals. TADF research started in earnest in 2012, and the first TADF emitters reached commercial status at the end of 2019.
There are currently three main challenges with OLED emitters that TADF aims to solve - an efficient and long-lasting blue color emitter, low cost alternatives current red and green emitters and the development of soluble OLEDs that can be deposited using low cost ink-jet printing or other "wet" methods.
TADF is being developed by several companies. Japan-based Kyulux was established to commercialize Prof. Adachi's HyperFluoresence technology, which combines two emitter systems, TADF and Fluorescence. Germany-based Cynora is focusing on a blue TADF emitter. Both companies are working hard to achieve commercial-ready materials. While a blue TADF (or HyperFluoresence) emitter is not here yet, in late 2019 Kyulux and Wisechip brought to market the first OLED with a yellow HF emitter.
Idemitsu Kosan also considers TADF as one of the key OLED technologies and intends to focus on TADF in the future. In late 2019 Idemitsu together with Toray announced the world's most efficient red OLED emitter - based on Idemitsu's TADF/HF material. UDC has been recently awarded a patent on TADF materials, although the company says that TADF is not in its focus.
The latest TADF news:
Hyperfluoresence emitter system developer Kyulux announced that its green material is getting close to commercialization. The company is now working closely with OLED makers, preparing for early adoption.
Kyulux says that its green emitter has not only met the required performance of OLED panel makers, in terms of efficiency, lifetime and driving voltage - but has actually surpassed the performance of green phosphorescent emitters in top emission devices. The green HF device achieves higher current efficiency, longer lifetime and offers a narrow emission spectrum and can thus enable better chromaticity.
During SID Display Week 2021, Kyulux detailed its latest TADF material performance. The red and green materials are "close to commercialization", and the company reports "excellent progress" with its blue emitter.
Using simulations, Kyulux shows how its Hyperfluorescence system is more efficient than a comparable phosphorescence emitter. While both emitters feature pretty much the same EQE, the narrow spectrum of the HF system which results in higher light intensity and can enable more efficient displays - by around 10%, according to Kyulux.
Kyulux raises $34 million in its latest funding round, receives basic HF TADF patent from Kyushu University
TADF materials developer Kyulux announced that it has finalized its Series-B-prime funding round, raising $34.3 million USD from several VCs and companies. Kyulux will be able to now accelerate its product development and drive for adoption of its materials in smartphone OLED displays.
Kyulux also announced plans to establish a mass production system for its materials, in cooperation with chemical companies.
Densely-packaged dimer-enhanced MR-TADF emitters demonstrate high efficiency with a narrow emission spectrum
Researchers from Soochow University, in collaboration with a wide team of scientists from China and Japan (including Prof. Adachi from Kyushu University) developed a TADF emitter material compound that features high efficiency and a narrow color spectrum.
Up until now, most TADF emitters featured a wide spectrum, which limits the adoption of TADF materials in displays as they cannot enable a wide color spectrum. To overcome this problem companies employ a structure in which the TADF emitter is combined with a narrow-spectrum fluorescence emitter (so-called Hyperfluorescence).
TADF OLED materials developer Kyulux announced a new CEO and President, to replace the current CEO Mr. Junji Adachi. Mr. Nakano will become the company's new CEO starting February 11, while Junji has been appointed as Chief Strategy Office. This is a part of a wide management change at Kyulux that reflects the company's transition from material development to commercialization.
Mr. Nakano has an impressive industry background in addition to management positions, and since 2014 he was an executive officer and manager director of Japan's Innovation Network (INCJ).
Cynora achieves breakthrough in its green TADF material, test kits are now available for display makers
OLED material developer Cynora announced that it achieved a breakthrough in its deep-green TADF material, which it brands as cyUltimateGreen. The new material delivers an efficiency of over 20% (EQE), a lifetime of 400 hours (LT95@15mA) and a color point and emission spectrum that matches today's DICI-P3 standard (Cynora does not specify the exact number).
Cynora further announced that is now making test kits of the new deep-green emitter available to its customers. Display makers can now start testing and verification using the new material. Cynora says it will also 'soon' follow with a deep-blue TADF solution.
Researchers at Osaka University developed an efficient heavy-metal free room-temperature phosphorescence OLED emitter
Researchers from Osaka University developed the best performing heavy-metal-free room-temperature phosphorescence (RTP) OLED emitters.
The researchers say that the new emitter (called SiAz), made entirely out of carbon, hydrogen, nitrogen, and silicon atoms, combines the mechanisms of TADF and RTP to create an efficient emitter system.
Kyushu University researchers developed a promising new two-unit stacked tandem Hyperfluorescence blue OLED emitter system
Researchers from Kyushu University reported that they have developed a promising new blue OLED emitter system, based on a two-unit stacked tandem hyperfluorescence OLED with improved singlet-excited-state energy transfer from a sky-blue assistant hetero-donor-type TADF (HDT-1) dopant.
The research reports that the new emitter system offers a pure-blue color (CIE 0.13, 0.16), a narrow spectrum (full-width at half-maximum of 19 nm), an EQE of 32% at 1,000 cd/m2 and a lifetime of 18 hours LT95. The lifetime is still lacking, but with stricter control of device fabrication and procedures the researchers say they expect that device lifetimes will further improve to rival commercial fluorescent blue OLEDs.
Korea-based SK Materials has established an OLED materials joint venture with Japan's JNC. The two companies will establish a new company called SK JNC (in which SK will hold 51%) that will produce OLED stack materials, including emitters.
The materials in production will be based on JNC's technologies and patents, including ones for blue emitters - apparently the main patent is for a TADF blue emitter. SK will provide its production and sales network.
Researchers from Canada's Polytechnique Montréal and the Université de Montréal developed a new near-infrared (840 nm) TADF OLED device that is 300% more efficient than existing ones. The IQE of the new deice is 3.8% - which is the best all-organic OLED emitter ever developed above 800 nm.
Photograph of the Polytechnique Montréal crest taken using visible and infrared illumination. Credit: Pr Sébastien Kéna-Cohen
To create the new OLED device, the researchers developed two new organic compounds - and were inspired by a class of molecules previously used for biomedical imaging.