TADF, 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 TADF technology. 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 HF) 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:
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 report 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 L%95. 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.
TADF emitter developer Kyulux announced that has signed a joint-development agreement with Nippon Soda to develop new intermediates compounds for TADF emitters. The goal of this collaboration is to improve the performance and quality of Kyulux's TADF materials, and also dramatically improve the production efficiency of new compounds.
This agreement also markets Nippon Soda first entry into the OLED market. The company, founded in 1920, is highly environmentally conscious and has accumulated advanced organic material development capabilities and vast synthesis know-how, which will assist it in this new OLED project.
Due to the global COVID-19 pandemic, the 5th annual International TADF Workshop and the 3rd i3-opera Forum, a companion event aimed at industry researchers, will be held on December 7–8 by means of online live streaming.
In the Workshop, novel scientific concepts will be discussed, as well as the future direction of TADF-OLEDs, perovskite LEDs, radical-based LEDs, QD-based LEDs, novel materials-based LEDs and more. In the Forum, the scope will be extended even further, to include topics ranging from TADF frontier science to interdisciplinary technologies for future lifestyle.
Eternal Material Technology starts to construct its 15-ton OLED material plant, updates on its OLED material and TASF project
China-based Eternal Material Technology (EMT) announced that it has started to construct its 15-tons OLED material production facility in Hefei. Yesterday the company held a groundbreaking ceremony at the construction site. EMT company expects the plant to begin mass producing materials in the second half of 2021. The planned total investment of the project (which will also include production of other materials) is 500 million yuan (or around $72 million USD).
EMT says that it has been able to achieve design wins for its ETL materials, and also other OLED related materials - and has already achieved sales of over 230 million Yuan ($33 million USD). EMT offers over 20 different OLED materials.
Kyulux presented a new paper at SID Displayweek, that shows the latest progress of the company's Hyperfluorescence OLED emitter platform. You can see the latest performance chart below.
Hyperfluorescence combines TADF and fluorescence emitters, which enables high-efficiency (~100% IQE) emitters that feature long lifetimes and a very narrow emission spectrum. The company's yellow HF emitter is already commercialized, and now Kyulux says that its red and green materials are "close to commercialization". The company is also improving the color point and lifetime of its HF blue emitters.
This is a sponsored post by Noctiluca
Poland-based TADF developer Noctiluca reports that the company continues to improve its emitter platform, and the company recently concluded testing a new family of emitters that have revealed great TADF properties, good to excellent QY and blue emission. Noctiluca released the raw data (available from company under the NDA) that details the performance of several new blue emitters. Here is a link to the summary of these results.
Noctiluca’s Team have a history of making custom high purity compounds to specific needs, and its TADF compound family has a high level of customization which will allow the company to tailor its materials for specific OLED stacks. In fact the company's next step is to work with industry leaders and OLED material developers to test its materials within commercial-grade OLED stack architectures to continue its development work and enhance the performance of its OLED emitters.
WiseChip Semiconductor, based in Taiwan, is one of the world's leading PMOLED maker (in fact in 2015 Wisechip said it's the world's second largest). Wisechip is developing next-generation PMOLED displays, including flexible panels, transparent panels and Hyperfluorescence/TADF PMOLEDs.
WiseChip recently announced its first, and the world’s first, Hyperfluorescence display, using TADF materials provided by Kyulux. Can you tell some more about this display and its properties?
This 2.70” 128x64 product is adopted mostly in industrial products. The size matters in such market but the main problem was to increase the brightness due to the limited efficiency of the fluorescence emitters. The Hyperfluorescence technology helps to settle the problem and can reach up 2.5 times brighter. It performs much better readability so users do not have to stand right in front of the device. This feature adds to the value of the end product.