Technical / Research - Page 19

Researchers from Korea's ETRI (Electronics and Telecommunications Research Institute) developed a flexible OLED panel that use a transparent graphene electrode. ETRI will detail this new graphene-based OLED panel at SID DisplayWeek 2018 in May.

A rigid graphene-based OLED prototype (ETRI 2017)

The researchers produced a "fully operational" 40x40 mm OLED panel that uses the pixelated graphene film as electrodes.

Researchers from Japan's Semiconductor Energy Laboratory (SEL) developed a novel Host-Guest system that drastically improves the lifetime of OLED emitters. The researchers report that using this system, a deep-red phosphorescent emitter achieved 5.4 times longer the lifetime compared to the same emitter with a conventional system.

The researchers will present the new system at SID DisplayWeek 2018 in May. The new system is not only highly durable, it also satisfies the red chromaticity of the BT.2020 standard.

Asahi Glass developed an ultra-thin chemically strengthened 0.07 mm flexible glass that has a bending stress of over 1200 MPa - which makes it possible to use this as a cover glass for foldable devices with a curvature radius of 2.5 mm or even lower.

AGC 0.1 mm flexible glass (2011)

To create this glass, AGC developed a new process that achieved 80% higher impact-failure resistance compared to glass with conventional chemical strengthening. AGC will discuss this new glass at SID Displayweek 2018 in May - and will also hopefully demonstrate it.

Researchers from the Max Planck Institute for Polymer Research developed a way to improve the current injection from the positive electrode in OLED panels. To enhance the hole injection the researchers covered the positive electrode with an ultrathin layer of an organic semiconductor as a spacer layer between the electrode and the light-emitting organic semiconductor.

Current flowing from an electrode (left) to the organic material (right) via a thin molecular layer (center)

The researchers say that they did not actually expect that adding an extra layer and eliminating the physical contact between the electrode and the emitting layer actually improves the electrical contact.

Germany launched a new project led by Merck to develop quantum materials as light emissive sources. The three-year project is called "Exploration of quantum materials New paths to realizing innovative optoelectronic components" (ELQ-LED) and it is supported by the German Federal Ministry of Education and Research (BMBF) and led by Merck with an aim to conduct basic research on quantum materials as light emitting sources. ELQ-LED is a three-year project that will end on the summer of 2020.

Merck hopes that ELQ-LED materials will enable ultra-pure colors, higher energy efficiency and lower production costs compared to current OLED emitters. The focus of this project will be on cadmium-free quantum materials but the partners will also develop supporting components, processes, transport materials and ink. All components developed in this project will be printable, and the project will test its developments in display prototypes and automotive tail light demonstrators.

Researchers from Korea's KAIST institute developed a technology to deposit OLED materials on thin fibers, ranging from 90 to 300 micrometers. The OLED on fibers had a luminance of 10,000 cd/m² and efficiency of 11 cd/A.

The researchers developed a unique OLED device architecture, which they say is more suitable for coating on fibers. The researchers also developed a "deep coating" process to deposit the OLEDs, which works under 105 degrees Celsius.

In 2015 the EU launched a 3-year €4 million OLED lighting project, the LEO project (Low-cost / energy Efficient OLEDs) that had an aim to develop efficient and cost-effective bendable OLED lighting technologies. The project consortium included Osram, and Cynora.

A month before the project officially ends, the partners updated on their progress. For this project, the partners develops several technologies, including low-cost metal foils integrating OLED anodes and possibly backside monitoring printed circuits, smart OLED top-electrode architectures and light out-coupling solutions and a novel thin film top-encapsulation strategies. These technologies together increased the light output by 50% while providing better surface scratch resistance.

US-based Solar-Tectic has launched a new low-temperature OLED backplane technology that could replace LTPS in future high-end mobile OLED displays and bridge the performance gap between IGZO and LTPS.

Solar-Tectic process, called LT1CS (Low temperature single crystal silicon) is a silicon based technology that creates highly oriented c-axis aligned or "textured" silicon crystals. Solar-Tectic says that the performance of LT1CS backplanes will be higher than IGZO performance. The company says that process is similar to SEL's CAAC-IGZO only based on silicon and not IGZO.

Graphene is the world's most impermeable material, and as the material is also transparent, flexible and ultra-thin it makes sense to adopt graphene as an encapsulation layer for next-gen OLED displays. A UK project led by Cambridge University researchers have set out in 2015 to develop such a solution, and the researchers now report that they have demonstrated a viable graphene solution comparable to existing commercial OLED encapsulation technologies.

In its pure form, graphene is permeable to all gases, but real life materials are never entirely pure and defects and holes harm the material's permeability. The new research used ALD and CVD to create large-area high-quality single-layer graphene sheets which were stacked to create a multi-layer coating. The researchers say that a ~10 nm barrier layer that includes 3-4 layers of graphene (with AlOx in between) is an effective solution for OLED displays. The 10 nm layer maintains a high optical transparency (>90 %) and high flexibility.

Researchers from Kyushu University has demonstrated the world's first glow-in-the-dark material that is made completely from organic materials. These materials can absorb light and release it slowly - with light emission lasting up to an hour.

Current solutions, used in watch hands and emergency signs, are in-organic, and also include heavy metals. In-organic GITD materials are also opaque. The new materials are transparent and much more environmental friendly, and are more cost effective as they contain only carbon based materials.