TADF OLED emitters, introduction and market status

Submitted by Ron Mertens on Sun, 02/10/2019 - 15:39

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.

Blue TADF emitter molecules

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 EU launched two TADF related collaborative research projects to focus on TADF emitters, Project HyperOLED and the 2015 project Phebe.

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The latest TADF news:

Researchers suggest using the dipole moments of TADF host materials to increase emission performance

Researchers from the University of Cambridge, led by Dr Alex Gillett, have studied the effect of host materials (the dielectric environment) on the performance of TADF OLED emitters, and specifically how the dipole moment of the host material can affect the rISC rate of the TADF component.

University of Cambridge: the impact of the toluene solvent dynamics on the riSC process of TXO-TPA

The impact of the toluene solvent dynamics on the riSC process of TXO-TPA (left: TXO-TPA in an explicit toluene solvent environment, right: TXO-TPA in vacuum)

The researchers tested several TADF OLED materials, and in some of these materials, the effect of different host materials can be quite dramatic. It is believed that commercial TADF devices could benefit from tuning the host and emitter combination to achieve higher performance, including a better efficiency roll-off as conversion of triplets into singlets can be accelerated.

Read the full story Posted: Nov 15,2022

Researchers from Shenzhen University designed efficient selenium-integrated TADF OLED emitters

Researchers from China's Shenzhen University are working towards efficient selenium-integrated TADF OLED emitters.

The researchers latest work detailed the structure-activity relationship between heavy atom effects and multiple resonance TADF performance. The researchers say that their new emitters effectively solve some of the issues inherent in TADF emission technology, specifically the sharp drop in emission at high brightness, what is called the emission roll-off.

Read the full story Posted: Oct 28,2022

Researchers develop new highly-efficient cyanopyrazine-enhanced fluorophores OLED emitters

Researchers from Russia's Ural Federal University developed a new OLED emitters based on cyanopyrazine-enhanced fluorophores. The presence of cyanogroup substance in the composition of fluorophores significantly increases the efficiency of the OLED emitters.

OLED based on push-pull-systems from cyanopyrazine compounds (Ural Federal University)

The researchers say that they have modified the pyrazine-based push-pull system with cyanogroup and studied how this affected the photophysical properties of the fluorophores and the performance of OLED devices based on these materials.

Read the full story Posted: Oct 21,2022

Samsung Display acquires TADF material developer Cynora

According to reports, Samsung Display acquired OLED material developer Cynora, for about $300 million. Samsung acquires just the IP and technology, and Cynora terminated its entire workforce a couple of weeks ago. Samsung is already an investor in Cynora, and so is LGD.

Cynora cyUltimateGreen TADF testing kit photo

Cynora has been low on cash (its last financing round was in 2019), according to reports, and did not manage to find new investors, and so the company opted to be sold to Samsung. The reported sum seems to be rather high for an emergency exit, and some later reports quotes much lower sums, perhaps even around $30 million or so.

Read the full story Posted: Jun 29,2022

Researchers developed promising N-doped PAH OLED emitters

Researchers from the Polish Academy of Sciences (PAS) and from the Silesian University of Technology have developed new OLED emitter materials based on aromatic electron-donating and -accepting moieties bridged by an antiaromatic seven-membered ring.

The researchers say that the new design of its N-doped PAHs is very flexible, and their properties are very responsive to the choice of the electron-accepting group. The researchers can thus can tune the emission mechanism between TADF emission and room temperature phosphorescence (RTP) emission, which gives high degree of control over the emission profile.

Read the full story Posted: Jun 23,2022

Kyulux explains how narrow-spectrum Hyperfluorescence emission is more efficient than PHOLED emission

Second-generation OLED phosphorescence emission features an internal quantum efficiency of almost 100% - which would normally mean you cannot get more efficient than that.

As Kyulux explains in a recent post, though, phosphorescent suffers from a wide emission spectrum. In order to achieve a good color gamut (for which as narrow-spectrum emission as possible is best) display makers have to filter out the "tail" of the emission. This results in reduced brightness and efficiency.

Read the full story Posted: May 26,2022

Kyulux says it is on track to commercialize green Hyperfluorescence materials in 2023, red and blue in 2024

Kyulux gave a very upbeat presentation at SID Displayweek, during which it updated on its latest material specification and its commercialization plans.

Kyulux RGB material performance (SID Displayweek 2022)

Kyulux managed to increase the lifetime of its Hyperfluorescence emitter systems (which features an IQE of 100% and a narrow emission spectrum) quite dramatically in the past year its green material now offers a lifetime of 59,000 hours (LT95@1000 nits, top emission), while the red material is at 20,000 hours. The blue material has also increase from280 hours to 450 hours in the past year.

Read the full story Posted: May 21,2022

SolOLED secures $250,000 to develop novel TADF emitters

UK-based SolOLED secured 200,000 GBP (almost $250,000 USD) in new funding from Scottish Enterprise to commercialize its novel OLED TADF emitter materials. SolOLED is launching a collaborative research project with CENSIS to commercialize the materials.

SolOLED was established in 2021 in the UK, to develop a family of novel solution-based TADF OLED emitter, based on technology that originated from the University of St. Andrews.

Read the full story Posted: May 11,2022

OLED innovation in Poland - 2022 status and future plans

Poland is aiming to become a major innovation and high-tech hub, and the country is already enjoying a growing industry, focusing on IT, bio-technology, robotics and nanotechnology.

Poland has a strong material science and development expertise, and in recent years we have been seeing OLED and display-related ventures out of Poland. It seems Poland is poised to become an interesting location to watch for future innovation in the OLED industry.

Ergis noDiffusion QD barrier image

Ergis Group noDiffusion OLED encapsulation film

One such company is the Poland-based Ergis Group, a leader in plastic processing active in markets such as food packaging, industrial, automotive, medical and more. In 2020, Ergis launched its first product for the optoelectronic applications (such as the display market and photovoltaics) - the Ergis noDiffusion films for flexible OLED panels (both displays and lighting) and OPVs. Ergis is using a unique ALD-based technology that enables it to offer high performance films on low cost PET films.

Read the full story Posted: Apr 12,2022