TADF OLED emitters, introduction and market status - Page 2

Researchers Durham University, led by Professor Andrew Monkman, discover new OLED emitters that offer high performance in a hyperfluorescence emission system. The main new material, a molecule called ACRSA, was found to triple the efficiency of hyperfluorescence OLED devices.

These OLED emitters aren't actually new - they were studied years ago, but were found to be poor emitters. That was true when used as OLED emitters, but when used in a hyperfluorescence system (which combines both fluorescent and TADF emitters), these were surprisingly efficient. The ACRSA emits a green emission, but deep blue light emission can be achieved by transferring ACRSA's energy to a blue terminal emitter. This approach reduces exciton energy compared to direct blue emission in devices, allowing more stable, longer-lasting blue OLEDs.

In 2023, we reported on research conducted at Germany's Max Planck Institute, led by Prof. Paul W.M. Blom, that looks into single-layer OLED devices. In such devices, a single TADF OLED emitter layer is sandwiched between two electrode - a much simpler design compared to commercial OLED devices that use multilayer stacks, sometimes with 10 or more layers. The researchers the the MPI say that in fact it is possible to develop highly efficient OLEDs with just the TADF emitter - and have demonstrated 100% IQE single-layer devices, with an EQE of 27.7%. 

Prof. Blom's group continues to improve its single-layer TADF OLED device, and have now reported that by employing a recently developed trap-free large band gap material as a host for the DMAC-BP OLED emitter, a nearly balanced charge transport is achieved. The device achieves a record power efficiency for DMAC-BP TADF OLEDs of 82 lm/W - surpassing  the best reported multilayer power efficiencies of 52.9–59 lm/W. This is due to the lower operating voltage. The single-layer device reaches an external quantum efficiency (EQE) of 19.6%, which is only slightly lower than the reported EQEs of 18.9–21% for multilayer devices. In addition to the high power efficiency, the operational stability is greatly improved compared to multilayer devices and the use of conventional host materials in combination with DMAC-BP as an emitter.

Kyulux announced that it has raised $28.6 million USD in its Series C funding round, led by El Camino Capital and the MCP Group. This brings Kyulux total funding so far to $86 million USD.

A part of the Kyulux team based in Fukuoka, Japan

Kyulxu says that it will use the newly raised funds to further accelerate its product development, strengthen its IP portfolio and achieve full-scale mass production of its emitter system by 2025, with its affiliated chemical companies.

Researchers from the University of Manchester, led by Prof. Alexander Romanov, developed a promising new Carbene-Gold-Arylacetylide (CMAc) OLED near UV emitter type. The researchers also detail a strategy to develop longer device lifetimes for such emitters.

The new emitter exhibits an efficiency of 1% EQE, and a lifetime of 20 minutes at a practical brightness of 10 nits (LT50). This is low compared to commercial OLEDs - but it is actually quite outstanding for such an emitter, and the researchers say that this is among the longest lifetimes for a near UV-OLED at a practical brightness ever reported. In addition, organic fluorescent and TADF emitters rarely exceed 1% EQE at practical brightness.

Poland-based TADF OLED emitter developer Noctiluca announced that it has signed an Evaluation License Agreement with a leading consumer electronics maker, based in California. In fact, Noctiluca says that its partner is the world's largest consumer electronics company, that has several products that utilize OLED displays.

It's likely that Noctiluca's partner is Apple, that is interested in testing the company's emitters. According to Noctiluca, its partner will test the materials at its R&D facility and laboratory in Taiwan. This is likely to be an early stage testing agreement, but still a very interesting development.

Researchers from Korea's KAIST institute, in collaboration with Gyeongsang National University developed a new TADF OLED deep-blue emitter molecule that achieves an EQE of 33%. Combined with a fluorescent emitter to create a hyperfluorescence system, the researchers achieved an EQE of 35.4%, with mitigated efficiency roll-off. The researchers say that this is the world's highest-efficiency narrow-band deep-blue TADF OLED emitter.

To develop the new emitter the researchers introduced sterically hindered peripheral phenyl groups to boron-based TADF emitter. The resulting material, o-Tol-ν-DABNA-Me, offers a pure narrowband emission that is far less sensitive to concentration compared to standard TADF emitters.

A few months ago we reported on research conducted at Germany's Max Planck Institute, led by Prof. Paul W.M. Blom, that looks into single-layer OLED devices. In such devices, a single TADF OLED emitter layer is sandwiched between two electrode - a much simpler design compared to commercial OLED devices that use multilayer stacks, sometimes with 10 or more layers.

The researchers the the MPI say that in fact it is possible to develop highly efficient OLEDs with just the TADF emitter, as there's no fundamental reason or major benefits that arise from multilayer OLEDs. The researchers continue their work, and now they have developed a new single-layer blue OLED in which every injected electron is converted into a photon - or 100% IQE. This is the first time that such a single-layer OLED device was demonstrated (see image above).

Researchers at the University of Chicago, led by Sihong Wang (above) and Juan de Pablo, developed a stretchable OLED device that uses TADF emitters to enable high efficiency and high stretchability.

The researchers say that this is the highest-efficiency stretchable display demonstrated to date, as all previous designs used fluorescent OLED emitters. The TADF stretchable device achieves 10% EQE and a stretchability of 125%. The substrate of this new device is a newly synthesized polymer.

PMOLED display maker Wisechip has launched its second TADF/HF OLED display, a 5.5" 256x64 yellow PMOLED device. The company says that by using Kyulux's Hyperfluoresence™ OLED technology it offers double the brightness compared to its standard OLEDs.

Wisechip is the first and only company to commercialize TADF/HF device. The company's first device was launched in 2020, a 2.7" yellow PMOLED.

This is a sponsored post by Nanomatch

Using their in-house virtual design tools, Nanomatch developed a new class of emitters that enables the production of stable, fluorescent OLED devices with close to 100% internal quantum efficiency also in the blue color range.

The specific class of fluorescent emitters facilitates the generation of only singlets with radiative decay of the order of 10-8s, thereby eliminating quenching processes induced by long-lived triplets. Having filed the patent end of February 2023, Nanomatch is now looking for partners to commercialize this new concept in order to realize efficient, stable blue OLEDs on an industrial level.