Fluorescent

Researchers from Sichuan University have used π-electron delocalization of classic PAHs molecules, through skeleton reconstruction, to design red fluorescence narrowband OLED emitters that offer the highest efficiency to date (24.2% EQE).

The researchers explain that their material design strategy enables the controllable transition of aromaticity from global delocalization to local localization, restricts long-range π-electron delocalization, suppresses excited-state vibrational coupling, and thus promises intrinsically narrow-spectrum emission materials.

Researchers from the University of Michigan and The Pennsylvania State University, in collaboration with OLEDWorks, has managed to create high aspect ratio OLED devices, by fabricating the OLEDs on substrates with sub-millimeter, high aspect ratio surface textures. This design increases the active OLED area per panel, reducing the local current density needed to achieve a given luminance.

The researchers report that this approach can extend the lifetime by up to 2.7X, this was verified on a blue fluorescent OLED device. These devices also offer up to 40% higher light extraction efficiency, as the corrugated substrates scatter the trapped light, significantly boosting EQE.

According to a report from China, HKC has successfully produced its first OLED display panel, produced at its Innovation Semiconductor Display Industrial Park in Shenzhen.

HKC says that it has managed to overcome all the previous challenges in its OLED production process, following about 5 months of R&D and technical progress. The smartphone-type AMOLED display is produced on an oxide-TFT backplane. The OLED architecture uses red and green phosphorescent emitters and a blue fluorescent emitter. 

LG Display announced that it has successfully verified the commercialization-level performance of blue phosphorescent OLED panels on a mass production line. LG is using a hybrid two-stack Tandem OLED structure, with blue fluorescence in the lower stack and blue phosphorescence in the upper stack. This enabled LG to achieve a power consumption reduction of 15%, while maintaining a similar level of stability to existing OLED panels.

The blue PHOLED emitter was supplied by Universal Display. LG Display says that it has independently filed patents for its hybrid blue phosphorescent OLED technology in both South Korea and the United States.

Researchers from France's Universite de Rennes and the Université Paris-Saclay have designed new graphene-based OLED emitters that outperform all previous graphene emitters.

The researchers designed green emitters based on rod-shaped nanographene materials containing C60-tBu8 materials, and incorporated these into a benchmark OLED device.  The OLED devices containing the C60-tBu8 exhibited current and power efficiencies (CE and PE) of 2.27 cd·A^–1, 0.28 lm·W^–1 and luminance of 164 cd·m^–2.

Researchers from the University of St Andrews, led by Prof. Ifor Samuel, have designed an OLED based communication device that achieves a record data rate of 3.2Gbps.

To realize this achievement, the researchers developed high-speed red, green and blue emitting OLED devices, on a single substrate. Using wavelength division multiplexing (WDM), the three OLED devices are emitting at the same time. By selecting fluorescent materials with nanosecond emission lifetimes and little overlap between their emission spectra, the researchers achieved a -6b dB electrical bandwidth of over 100 Mhz. 

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 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.