Technical / Research - Page 8

Researchers at the University of St Andrews and the University of Cologne developed a polariton-based OLED device that offers angle-independent narrowband emission.

Polariton-Exciton quasiparticles are created when an OLED material is inserted into a high-quality microcavity. The researchers explain that by sandwiching the OLED device between two "mirrors", strong coupling and hybridization of light and matter can occur. This leads to the creation of the polariton particles. 

Researchers from Korea's Pusan National University have developed a new low-cost hole injection layer (HIL) material for solution-processed OLEDs, achieving higher efficiency and lifetime compared to the current state-of-the-art.

The new material is solvent-resistant (>99%) and thermally cross-linkable. The researchers used this material to create a solution-procssed red phosphorescent OLED device. The researchers placed the material between the ITO electrode and the HTL material, thus achieving photo-crosslinking of (poly-TPD) as HTL on top of crosslinked HIL. 

Researchers from Germany's Max Planck Institute, led by Prof. Paul W.M. Blom, are looking into single-layer OLED devices (in which a single emitting layer is sandwiched between two electrodes), with an aim to match their efficiencies to those of common multilayer OLED stacks, like the ones used in commercial OLED displays.

Current OLED architectures utilize multilayer stacks of materials, in order to increase the performance and lifetime of OLED devices. But according to the latest findings by Prof. Blom, equal efficiencies can indeed be met with single-layer TADF OLED emitters - and there's no fundamental reason or major benefits that arise from multilayer OLEDs.

Industrial inkjet printing developer Notion Systems announced that is has been selected by the Institute of Chemistry, Chinese Academy of Sciences (ICASS) for organic material R&D. Notion Systems worked together with its partner YixinTech as its system went through a long comparison against other inkjet printers in the market.

ICCAS is a multi-disciplinary research institute dedicated to basic research in broad fields of chemical sciences. One of its major research areas is organic materials for display applications.

In May 2022 we reported that LG Display is looking into adopting a microLens array in its large OLED TV panel architecture. The microlens layer could boost brightness by up to 20%, which will also increase efficiency (if brightness is kept as before). According to a new report from Korea, LGD is progressing in its project and estimates that the first MLA (Micro Lens Array) OLED panels will enter production in 2024.

MicroLens array structure, University of Michigan

The original report in May stated that LGD could actually begin producing MLA OLEDs as early as in 2022 - but it seems as this was overly optimistic. Earlier this year, LGD demonstrated a 77" 8K MLA WOLED panel.

Researchers from Korea's KAIST institute developed a fabric-based wearable patch that uses a blue OLED device to treat jaundice in newborns.

The researchers say that phototherapy is the most widely used treatment for neonatal jaundice, as it is a safe and effective to transform the bilirubin that is accumulated in the body and release it. When the bilirubin concentration is too high, the doctors treat newborns with blue light in an incubator. The new device can be used to treat high levels of bilirubin, without the need for an incubator.

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.

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.

Toray Research Center (TRC) is now hosting online webinars focused on display technologies. TRC, who supplies technical analysis and support for R&D and manufacturing, invites you to attend the online lectures at no cost, to learn more about OLED, microLED and QD technologies and analysis of OLED devices.

The webinars include recorded presentations, which will be available online up until to November 22. You can register for the webinars here.

The webinar will include three different presentations:

• OLED dopant ratio for efficient emission
• Laser-based processes for microLED production, analysis method to evaluate chips after transfer
• Degradation analysis of QD-LED devices

In the next two weeks, Toray Research Center (TRC) is hosting online webinars focused on display technologies. TRC, who supplies technical analysis and support for R&D and manufacturing, invites you to attend the online lectures at no cost, to learn more about OLED, microLED and QD technologies and analysis of OLED devices.

The webinars include recorded presentations, which will be available online up until to November 22. You can register for the webinars here.

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.