Technical / Research - Page 14

Researchers from the University of Michigan, in collaboration with Universal Display are developing a low-cost roll-to-roll (R2R) process to produce flexible OLED lighting panels. The goal is to achieve a panel cost of less than $10 per klm - a tenfold reduction compared to current costs.

The roll-to-coll system can continuously produce encapsulation panels, at high speeds and reduce costs. The front plane (organic stack) deposition is done via OVPD. The researchers say the will demonstrate reliable, encapsulated 25 cm² flexible white OLED panels with an efficacy of 50 lm/W and a CRI >85 on barrier-coated plastic films or thin glass.

Researchers from Stanford university in collaboration with Samsung's Advanced Institute of Technology (SAIT) developed a new OLED structure that enables resolution of up to 10,000 PPI, high brightness and a cost-effective production process.

In the new so-called Metaphotonic OLED structure, the panel is produced on a base layer of reflective metal with nanoscale corrugations. This 'metasurface' can manipulate the reflective properties of light and thereby allow different colors to resonate in the OLED sub-pixels.

Researchers at Penn State University, with funding from the DOE, suggest a new way to improve the light extraction from OLED devices (EQE). The idea is to introduce electrically inert and low cost "dilution" molecules to the hole and electron transport layers, and so reduce the reflection of these layers which increases the outcoupling efficiency of these layers.

The added molecules do not degrade and actual performance - and should not increase production costs. The researchers are currently modeling and simulating molecules and device stacks. Eventually, the researchers aim to demonstrate multi-stack OLEDs with internal light extraction efficiency exceeding 75%.

Researchers at Universal Display, developed an OLED device with plasmonic decay rate enhancement that dramatically increase device stability. By including a nanoparticle-based out-coupling scheme to extract energy from the plasmon mode, the researchers managed to maintain the device efficiency.

The device used an archetypal phosphorescent emitter to achieve a two-fold increase in functional stability at the same brightness as a reference conventional OLED device and extracted 16% of the energy from the plasmon mode as light.

Researchers from North Carolina State University developed a new technique that could drastically lower the cost of ultrasound acoustic imaging, using OLED displays. The researchers say that ultrasound receivers could be made with costs of around $100 - compared to current systems which cost $100,000 or more.

The researchers fabricated an OLED on top of a piezoelectric transducer. When ultrasonic waves interact with the transducer, it lights up the OLED display. This create a very simple ultrasound device compared to current devices.

Samsung Display has developed a 18.2" 2560x1440 202 PPI inkjet-printed OLED display, that features the highest current efficiency of any inkjet-printed OLED, with the brightness at 350 cd/m² (full white).

Samsung Display says that the high brightness was achieved by tuning the top-emission device structure with high performance soluble materials. The high pixel resolution was achieved by modulating the jetting waveform for ejecting ink drops and improving the drop placement accuracy by selecting the right ink formulations in terms of viscosities and surface energies.

Kyulux presented a new paper at SID Displayweek, that shows the latest progress of the company's Hyperfluorescence OLED emitter platform. You can see the latest performance chart below.

Hyperfluorescence combines TADF and fluorescence emitters, which enables high-efficiency (~100% IQE) emitters that feature long lifetimes and a very narrow emission spectrum. The company's yellow HF emitter is already commercialized, and now Kyulux says that its red and green materials are "close to commercialization". The company is also improving the color point and lifetime of its HF blue emitters.

OLED lighting developer OLEDWorks announced that it has developed a high-performance multi-stack OLED microdisplay technology. Next week at SID Displayweek OLEDWorks will present the technology, and results from 3, 4 and 5-stack microdisplay formulations.

OLEDWorks explains that it has realized its multi-stack OLED lighting technology - and the results are "exceptional". The company says that combined wit its unique and cost-effective manufacturing technology, microdisplays based on this new technology could combine high brightness, long lifetimes, exceptional power efficiencies - all at a low manufacturing cost.

Researchers from Yonsei University in Korea developed a full-color wearable AMOLED display that can be placed directly on human skin. The device can be flexed and stretched as needed.

The researchers demonstrated a 18x18 AMOLED array, fabricated on a thin substrate with a 2D MoS₂ (a graphene-like material) backplane.

OLED producers are looking at under-the-OLED cameras - this is a great technology that could enable complete bezel-less smartphone displays without any pop-up selfie cameras. Samsung, in 2018, announced it is working on several behind-the-OLED sensors, including a camera. But China's Visionox is the first company that actually launched such a technology commercially.

Microsoft recently published an interesting research project (led by Sehoon Lim) that discusses the potential use cases of under-the-OLED camera and its advantages, and also the challenges - with AI technologies that could assist in solving these issues.