Blue color

In recent years, the main focus of the OLED industry was on reducing power consumption. OLED developers introduced several novel technologies, including new backplanes, materials and device architectures, to increase device and system efficiency.

This article looks into the potential pressure that the acceleration of on-device AI (locally running AI engines as opposed cloud-based AI) will have on OLED developers to reduce the power consumption even further, especially within the laptop segment, and adopt novel next-gen technologies.

Researchers from the Changchun Institute of Applied Chemistry (CIAC), working with collaborators from the University of Science and Technology of China and Central China Normal University, developed a new deep-blue OLED device architecture that reaches an external quantum efficiency (EQE) of 42.0%, a record for this device class.

The OLED device is based on MR-TADF emitters, that combine high efficiency with narrowband, high-purity emission through fast exciton conversion. The researchers say that reaching over 40% EQE in this class has been difficult because most MR-TADF emitters have a low horizontal dipole ratio, which limits how much light can actually be extracted from the device.

Researchers at Nagoya University and Kyushu University have utilized AI and machine learning to design new OLED TADF emitter molecules, focusing on "boron-free" 13-ring frameworks. 

The researchers restricted the molecules to contain only carbon, hydrogen and nitrogen atoms, and generated a virtual library with more than 19,000 molecules. Out of these molecules, 17,000 could be 3D modeled, and then after large-scale screening, 50 promising candidates were selected for higher-level quantum chemical calculations. Finally, the two most promising molecules were selected to be synthesized and tested in actual OLED devices.

LORDIN has publicly disclosed the molecular structure behind its ZETPLEX platinum (Pt) dopant concept, publishing the work in a peer-reviewed paper. The disclosure marks the first time the company has revealed the chemistry underlying its materials. 

LORDIN says that the material structure leads to a simplified deposition process while also improving device lifetime.

Researchers from Kyung Hee University published a new study in Advanced Functional Materials that studies the the causses of the short operational lifetime of blue phosphorescent OLEDs. 

The researchers say that intrinsic material toughness (things like bond dissociation energy and molecular rigidity) is not enough to predict how long a device will actually last, because materials with very similar chemical stability can show dramatically different lifetimes. To get to the root cause, the researchers combined two complementary characterization techniques: transient photoluminescence (TrPL), which measures a material's intrinsic exciton behavior under optical excitation, and magneto-electroluminescence (MEL), which probes exciton dynamics under actual electrical operation.

Researchers from Kyoto University, have developed a new molecular design concept for MR-TADF OLED emitters, that spatially expands and amplifies the multiple resonance effect. 

The new molecule, called m-CzB10-Mes has a nano-carbon framework, with a ladder-type structure, and it achieved an emission bandwidth dramatically smaller than those of conventional multiple resonance emitters. Furthermore, the molecule also exhibits excellent TADF performance. 

A couple of months ago we reported that  the Korean Supreme Court upheld the validity of SFC's blue OLED emitter patent, and did not accept the claims by SK Materials JNC (SKMJ) that the patent was invalid.

Now we hear from Korea that SFC has won a civil lawsuit against SKMJ, and was awarded with 100 million Won in damages ($65,000 USD) plus all litigation expense. SFC was also seeking to ban SKMJ from marketing this material, and its likely that this is part of the court's decision. 

We're excited to launch Bright Side with Brannan, a new column by Prof. Alexander Brannan of the University of Manchester. In this column, Prof. Brannan will explore the science behind OLED technology — the materials, the physics, and the open questions driving the field forward. The following article is the first in the series.

OLED emitter materials are currently dominated by closed-shell compounds. This means their occupied molecular orbitals, including the highest occupied molecular orbital, or HOMO, are fully occupied by paired electrons in the ground state. In other words, there are no unpaired electrons.

This electronic structure underpins the conventional OLED emitter families: fluorescent, phosphorescent, and thermally activated delayed fluorescence (TADF) emitters. In each case, the excited states are usually described within the traditional singlet and triplet framework.