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

KT&T, established in 2020 as a spin-off from INT Tech with an investment of $143 million, has developed an OLED microdisplay that achieved a brightness of 12,000 nits, which is the highest brightness OLED microdisplay ever developed.

The new panel is based on KT&T's own uNEEDXR technology, which is a direct-emission (no color filters) design. The display achieves very high brightness and high efficiency.

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.

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.

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.

Researchers from the Université de Rennes in France have developed a simplified PHOLED green emitter that achieves the world's highest efficiency in single-layer PHOLEDs - an EQE of 22.7%.

The researchers, led by Prof. Cyril Poriel, say that the emissive layer was developed using a rational molecular design. The impact of the phosphorescent emitter on the ambipolarity of the charge transport is particularly evidenced and appear as a key concept in the high performance that was achieved.

A few months ago, Japan Display (JDI) announced that it has developed a "historic breakthrough in display technology" - a new OLED deposition process which they refer to as eLEAP, that is said to be cost effective and can be used to create freeform OLEDs that are brighter, more efficient, and longer lasting compared to OLEDs produced using mask evaporation (FMM).

According to a new report from Korea, Samsung Display is interested in JDI's new technique. Interestingly the report shows conflicting views within SDC - some are interested in adopting this new technology, especially at SDC's upcoming 8-Gen IT OLED production line, while others are more interested in preventing SDC's competitors (JDI, or others?) from using it, perhaps by pressuring OLED equipment makers to not offer needed equipment to JDI.

TCL (CSoT) announced that the company has finalized the development of several new OLED technologies, which has been deployed at the company's production lines.

The first technology is LTPO, or Low-Temperature Polycrystalline Oxide, an OLED backplane technology developed originally by Apple. LTPO enables variable refresh rates, and TCL's technology can support a wide range of frequencies, from 1Hz to 144Hz.

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.

Idemitsu Kosan announced that it has developed the world's most efficient blue fluorescence OLED emitter system. Idemitsu's new system achieves an EQE of 14% (at current density of 10 mA/cm²), a lifetime of over 400 hours (LT95 @ 50 mA/cm²) and a color point of (0.14,0.08).

The new material system uses a tandem structure of two blue OLED emitter layers. Idemitsu says that by separating the region that causes charge recombination and utilizing TTF (Triplet-Triplet Fusion) it managed to achieve the high light output.