Technical / Research - Page 12

Researchers from Jilin Univeristy in Changchun, China, have managed to improve the brightness of OLED devices by 25% (21 enhancement in current efficiency) by applying corrugated alloy (Ag-Al) electrodes.

AFM images of the corrugated alloy electrodes

The researchers say that the periodic corrugations were precisely tuned based on the composition ratio of the alloy to efficiently recover the photons trapped in surface plasmon-polariton resonance.

Researchers from Europe, working with funding from the EU research program at the MOLOKO project, developed a new plasmonic sensor system that integrates an organic light-emitting transistor (OLET), an organic photo-diode (OPD), and a nanostructured plasmonic grating (NPG) all in the same device.

The researchers say that this design enables to create cost-effective and highly miniaturized optical sensors based on the optics-less plasmonic system. The researchers further say that the potential of OLETs, as planar multielectrode devices with inherent micrometer-wide emission areas, offers the incorporation of the light-emitting and light-detection modules together at unprecedented lateral proximity.

Organic-TFT backplane/emitter developer Mattrix Technologies has demonstrated a new AMOLED display prototype that is based on an amorphous-silicon (a:Si) backplane.

Mattrix believes that its proprietary vertical, organic light-emitting transistor (VOLET) pixel technology can dramatically reduce OLED production costs and improve display quality.

Last year, Poland-based Ergis Group launched an OLED encapsulation film platform called Ergis noDiffusion®. The company is currently testing its film solutions at customer sites in Asia, the EU and the US, and it is now starting to expand the platform for the protection of quantum dot films (QD films) used in display and lighting applications.

These new films can be tuned to fit specific needs. Ergis can deploy its films on several substrate types, with varying film thickness, and the barrier properties can be tuned to be between 10^-6 to 10^-3. This means that custom films can be created to suit the specific sensitivity of the QDs for water vapor and to achieve specific product lifetime or other required properties.

The National Center for Flexible Electronics (FlexE) was established in 2014 as a Centre of Excellence at the Indian Institute of Technology (IIT) in Kanpur. The vision of the center is to "catalyse the development of domestic industry in the field of large area flexible electronics".

The FlexE center has some interesting OLED projects, and we recently had a discussion with researchers from the center to learn more about the OLED R&D activities.

Taiwan's National Tsing-Hua University (NTHU) Professor Jou and Dr. Wen have been developing OLED lighting technologies for many years, focusing on healthy bluelight-free OLEDs (so-called candle-light OLEDs) due to the hazards of modern lighting.

The researchers now report they have developed a new tandem-OLED device that improves the efficiency and lifetime of their candle-light OLEDs. The OLED's emission is totally blue-light free, which makes it even safer compared to NTHU's first-gen candle-light OLEDs.

Researchers from the University of Tsukuba in Japan have compared the effects of LED and OLED lighting on physical processes that occur during sleep. The researchers show that OLED exposure has a reduced effect on sleep architecture and energy metabolism.

OLED devices emits white light which contains less blue light compared to LED devices, and this does not lead to any effect on sleep architecture, but it does reduce energy expenditure and core body temperature. In addition, fat oxidation during sleep was significantly lower after exposure to LED compared with OLED. Thus OLED lighting has a similar effect to that of dim light.

Researchers from the University of Michigan developed a new electrode design for OLED devices, that can increase light output by up to 20% compared to current electrodes. The new electrode is compatible with current production processes.

The new design helps to minimize the waveguiding effect, which traps around 80% of the light produced by the OLED emitters. The researchers used a modal elimination approach, which involves optimizing the organic stack and the replacing the ITO anode with a thin film of silver deposited on a layer of copper. This kind of approach can be applied to other light emitting structures such as inorganic LEDs, perovskite LEDs, quantum dots and more.

Researchers from Samsung Advanced Institute of Technology (SAIT) developed a new stretchable OLED display, that features stable performance and high elongation possibility. Samsung says that this research is the first one to prove the commercialization potential of stretchable devices.

The new stretchable OLED was integrated with a photoplethysmography (PPG) sensor in a single device. The PPG sensor is used to measure the user’s heart rate in real-time - which can be displayed on the OLED display.

Researchers from Yonsei University developed a new OLED device that is highly stretchable. The researchers managed to build the entire device, including the substrate, conductive wires, electrodes and OLED layers, from stretchable materials.

The researchers say that this is the first time that the complete display device was produced from stretchable components, unlike previous efforts which have mainly focused on connecting small rigid OLED devices together to create a stretchable device.