OLED Lifetime

Researchers from Seoul National University (SNU), in collaboration from colleagues from Samsung's SAIT institute, have identified a critical mechanism behind the performance degradation of OLED devices, the interfacial exciton-polaron quenching mechanism.

The researches have theoretically proposed a mechanism where excitons in the light-emitting layer are quenched by the accumulated charges at the interface. They followed with with experiments that have independently observed this phenomenon, identifying three key factors: interfacial barrier, exciton-polaron distance, and exciton lifetime. 

A few months ago Inuru started shipping its range of OLED-powered stickers, or "holo tags" as the company refers to them. These are battery-powered flexible stickers that can be used for laptops or any other use.

The company was kind enough to send us three stickers, from their latest Cyberpunk range. These stickers cost around 20 Euros, and there are many alternative designs. The idea is that the flexible stickers include a small OLED, a battery and a button that lights up the OLED for a few seconds. The whole device is said to be waterproof, but I did not test it.

Inuru says that the lifetime of the OLED is about 5,000 hours. As the battery is limited, though, they say that each sticker is limited at around 2,500 clicks. Some of them use a red OLED, and some a blue one.

LG Electronics is going to add screensaver ads to its TVs, including its high-end OLED TV range. It seemed the company has already started testing this new feature, which shows full-screen ads, and the company will offer a way to turn the ads off, as it markets the new ad system a "feature".

LG Ad Solutions company announced the new "Native Screensaver Ads" feature, that "capitalizes on idle screen time, turning what may be perceived as a period of downtime into a valuable engagement opportunity".

Researchers from LORDIN, in collaboratioon with researchers from Korea's Dankook University, Gachon University and Hongik University, have reported on a highly efficient and stable ultra-pure blue phosphorescent OLED emitter, based on Lordin's Tetradentate Pt(II) material Complex with a vibration suppression effect.

The researchers say that the new emitter offers a lifetime of 451 hours (LT50 at 1,000 cd/m²), and an EQE of 25.1%. The emission spectrum is extremely narrow - full width at half a maximum of 22 nm. The researchers further developed a tandem OLED device based on this new emitter, which achieves an EQE of 50.3% and a lifetime of 589 hours (LT 70).

Researchers from Tsinghua University in Shenzhen, China, have managed to dramatically increase the stability of OLED devices by the adoption of deuterated host material.

The researchers, led by Prof. Man-Chung Tang, have designed and synthesized deuterated anthracene-based hydrocarbon PNA as the new host material. The researchers have observed that the faraday loss decreases with the increase of the deuteration degree.

A report from Korea says that LG Display has successfully developed an OLED panel that is based on a blue phosphorescence emitter. The blue PHOLED, provided by Universal Display, offers 100% IQE, up from 25% used by current fluorescence emitters. This will result in around 20-30% power saving for the display itself (depending on the images shown).

UDC has been developing blue emitters for many years, and recently the company said that the development will take a few more months and won't be ready in 2024. The main challenge is increasing the lifetime of the materials. However LG Display has adopted a tandem design to enable a commercially ready display, perhaps even sooner than UDC planned.

OLED displays have been gaining popularity rapidly, and are already the dominant smartphone display technology. OLEDs are also the display technology of choice in the smartwatch market, making inroads into the TV, monitor, laptop and tablet markets. The future of the OLED industry looks bright.

In recent years, the focus of the industry, beyond increasing capacity and reducing production costs, has been improving the performance of OLEDs in the areas of display brightness, efficiency, and lifetime. Brightness is required in many applications - from TVs (for HDR and to view in ambient lighting) through smartphones (outdoor viewing) to automotive, and efficiency is a plus in any scenario (but mostly in mobile displays). Display lifetime is already good enough for many applications, but in some cases (like automotive, and IT displays) it is critical. These three properties usually go together - if you can make more efficient OLED displays, you can drive them at a lower current to achieve the same brightness, and so lifetime increases, or you can achieve higher brightness, etc. 

LG Display says that it has started to mass produce tandem OLED laptop panels, the first company to do so. LGD says its tandem architecture double the lifetime of its OLEDs, reduce power consumption by up to 40%, and enable up to three times the brightness.

LGD has been producing tandem OLED displays since 2019, mainly for the automotive industry. This expertise has enabled it to be Apple's main tandem OLED display suppler for its 2024 iPad Pro devices, and now to be the first one to produce tandem laptop panels. 

Researchers from the University of Manchester, University of Cambridge and University of Eastern Finland, led by Dr. Alexander Romanov have developed a new deep-blue Carbene-Metal-Amide (CMA) OLED emitter material with promising operating lifetime.

The emitter is based on a a new CMA complex with a rigid amide donor, benzoguanidine. The researcher say that the new design unlocks bright charge-transfer deep-blue emission with 100% photoluminescence quantum yields. The excited state lifetimes of the new CMA complexes are among the lowest reported to date among all TADF emitters
(down to 213 ns), resulting in remarkably fast radiative rates of up to 4.7 × 10 6 s⁻¹ .