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 TADF emitters are expected to become commercial by 2018.
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 aim to release their first commercial materials in late 2017 or early 2018.
Idemitsu Kosan also considers TADF as one of the key OLED technologies and intends to focus on TADF in the future (although Idemitsu's actual TADF plans are not clear yet). 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:
A new company has recently been launched in Poland, to commercialize a new family of TADF OLED compounds. Noctiluca, which takes its name from a bio-luminescent marine creature, was established a few months ago with aims to be the world's first company to produce a commercial-ready blue TADF emitter.
Noctiluca's story begins with an innovative organic DSSC solar cell platform that was developed at Synthex, an organic chemistry development platform company based in Toruń, Poland. A few years ago the researchers turned their attention to light emitting materials (which are quite similar to the light harvesting materials used in solar panels) and intensive research culminated in a promising family of new TADF compounds - which was then spun-off as Noctiluca,
Wisechip announced that it launched the world's first Hyperfluorescence OLED display - a 2.7" monochrome yellow 128x64 PMOLED. The brightness of this display reaches 220 nits - which is 2.5 times the brightness of Wisechip's fluorescent yellow PMOLED. The lifetime of this display is 50,000 hours.
Hyperfluorescence OLED emitters represent the 4th-generation of OLED emitter systems. HF is an actually a system that combines fluorescence emitters (1st-gen) with TADF (3rd-gen) hosts - to achieve a high efficiency , long lifetimes and narrow-spectrum emission.
Researchers from the Max Planck Institute for Polymer Research (MPI-P) have developed an efficient OLED device that is comprised of a single organic material layer - replacing the normal stack of 5-7 layers in modern OLED devices.
The researchers managed to create this OLED device by using a TADF material (CzDBA, diboron based TADF) and by using a newly developed charge injection strategy. The OLED device features a low operating voltage (2.9V at 10,000 cd/m2, an EQE of 19% (at 500 cd/m2) and a lifetime of 1,880 hours at 50% (for 1,000 cd/m2). The color of the device is greenish-yellow.
TADF and Hyperfluorescence developer Kyulux announced that it finalized its Series B financing round, having raised ¥1.5 billion ($31.8 million USD) from several companies and VCs. Kyulux says it will use the funds to further accelerate product development and strengthen its IP.
A couple of months ago Kyulux updated on its latest TADF device that achieves 200 hours of lifetime (LT95 at 1000 nits) and an EQE of 22% (at 1000 nits). The color point is 470 nm (which is not deep-blue, note). Kyulux also says that Wisechip is now ready to start producing the yellow HF PMOLED and is seeking customers.
TADF developer CYNORA announced that it has secured $25 million in its Series C funding round from investors in Asia, Europe and the US. Since 2008, Cynora raised $80 million.
Cynora's latest deep-blue material specification was presented in May 2018 - with a CIEy of 0.14, EQE of 20% and a lifetime of 20 hours LT97 at 700 nits. Cynora expects to have blue material in mass production by 2020. In October 2018 Cynora extended its joint-development agreement with LG Display.
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 was discovered 10 years ago, and the 4th International TADF Workshop will mark the event.
The TADF Workshop will cover a diverse range of topics in TADF, excitonic materials, physics and devices - including a special focus on device architectures, up-conversion mechanisms, radical (doublet) emitters and perovskite emitters.
In June 2018 Kyulux and Wisechip unveiled a PMOLED display that uses Kyulux’s Hyperfluorescence yellow emitter. Kyulux updated today that Wisechip is now ready to start producing the HF panel and is seeking customers.
Wisechip eventually settled on a large panel - 73.00 x 41.86 mm (2.7") with a resolution of 128x64. Wisechip says that the power consumption of its HF display is almost half of its regular fluorescent yellow PMOLED.
The first day of the OLED Korea 2019 conference is almost over - with some interesting lectures and talks by leading OLED companies and professionals. Here are some of the things under discussion today (highlights only):
- Some believe there will be a real market for >$2,000 foldable OLED devices, and some call for cost reductions before real adoption could take place
- LG Display is optimistic regarding the future of OLED TVs
- Samsung will not commit yet to its QD-OLED technology
- Both Cynora and Kyulux are rapidly progressing towards a long lasting TADF/HF blue - but it seems there's still work to be done
- Idemitsu Kosan is increasing its fluorescent OLED emitter efficiency
- Universal Display's RGBB architecture is back on the table - and the company now highlights the architecture's low blue light emission. UDC seems more optimistic then ever regarding blue PHOLED commercialization
- Equipment maker's focus is shifting to China as Korean OLED makers will not increase capacity in the near future
US-based OLED material developer Molecular Glasses received a $225,000 SBIR Phase I grant from the National Science Foundation to develop non-crystallizable charge transporting organic materials as OLED functional layers and thermally activated delayed fluorescence (TADF) emitter-layer hosts.
The NSF explains currently used OLED host molecules tend to crystallize and are poor solvents for the emitting molecules leading to decreased light emission efficiency and shortened device lifetime. Molecular Glasses' innovation uses isomeric mixtures of designed molecules that are amorphous and non-crystallizable in all three layers.
Researchers from the University of Cambridge and Jilin University discovered that radical-based OLEDs feature highly efficient emission - in fact they believe that this discovery could be an elegant solution to the problem of in-efficient OLED emission.
First-generation OLED emitters (fluorescent emitters) have a maximum internal quantum efficiency of 25% - as only a quarter of the electrons are in a singlet-state (that emit light) while 75% of the electrons are in a triplet-state. Current ways to achieve 100% IQE are either based on doping with heavy metals (phosphorescent emission) or either based on delayed fluorescence (TADF).