Technical / Research - Page 20

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.

The Fraunhofer FEP institute, in collaboration with Nippon Steel & Sumikin Materials (NSMAT) and Nippon Steel & Sumitomo Metal Corporation (NSSMC), developed a new OLED lighting prototype that is made on a stainless steel substrate.

The researchers say that a stainless steel substrate has several advantages compared to glass or plastic - it has excellent thermal conductivity and excellent barrier properties. The lighting panel features an extremely homogenous OLED light, thanks to the planarization layer developed by NSSMC. The prototype panel was produced at the Fraunhofer's R2R research line.

Visionox announced that it has chosen Israel-based Orbotech to supply it with an end-to-end automated optical inspection (AOI) solutions for its upcoming 6-Gen flexible AMOLED fab in Hebei.

This deal includes a large number of Orbotech AOI systems for TFT Array and OLED-related layers for inspection and classification. Among the solutions provided is the Orbotech Quantum Flex series, which will resolve challenges that manufacturers typically face with OLED flexible display processes. The solution includes unique technologies to address the requirements of flexible OLED panel inspection.

Last year researchers from Korea's KAIST institute developed a process to deposit OLED displays on textile substrates. Using several-micrometer-thick fibers, the researcher created thin fabrics from these fibers and coated them with OLED materials which were then encapsulated to achieve a lifetime of 1,000 hours.

The same KAIST group now announced that this OLED-on-fabric program is advancing. The researchers now report that their latest prototype "OLED-clothing-device" has high lifetimes and feature good electro-optic characteristics. The bending radius of the new fabric is only 2 mm. The researchers say that this new prototype is the most flexible and highest performing OLED on fabric ever demonstrated.

Korea's Institute of Science and Technology (KAIST) and the country's Engineering Research Center (ERC) are jointly establishing a new OLED light therapy engineering center.

The new R&D center will initially target skin wound treatment and sleep disorder treatment, using flexible OLEDs to replace current LED-based solutions. In the longer range, the center will also look into dementia prevention and treatment, mild cognitive impairment solutions and other diseases.

Researchers from Korea's National University developed a new process based on high-pressure gas sprays that can be used to rapidly transfer OLED layers very quickly - which could reduce the manufacturing time of OLED panels by 90%.

The new process uses a new air jet technology that sprays desquamating gas such as nitrogen, argon and air at high pressures. The gas is sprayed at a speed of 300 m/s between the OLED and a substrate - which reduces the binding power of the OLED from the substrate, and increases the binding energy of the organic layers being transferred. This can be used to quickly transfer thin films without damage them.

Researchers from Kyushu University's Center for Organic Photonics and Electronics Research (OPERA) developed a new TADF emitter molecule that is based on excited-state intramolecular proton transfer (ESIPT).

The researchers says that ESIPT can be used to design completely new TADF materials, which could enable researchers to achieve a high performance and long-lasting emitter structure, as a new material family may expand the molecule design possibilities. TADF from a ESIPT molecule has been reported previously - but the researchers say that this is the first demonstration of highly efficient TADF observed inside and outside of a device.

Fraunhofer FEP and Sefar developed a roll-to-roll processed large-area flexible OLED lighting panels in a joint project. This achievement followed a batch-based flexible OLED panel demonstrated in early 2017.

The R2R process currently used enables Fraunhofer and Sefar to produce 30 cm wide OLEDs in lengths of up to 30 meters.

Researchers at the University of California, Santa Barbara and the Dow Chemical Company have chosen a bottom-up approach to patterning emissive polymers, aiming to solve some of the problems that plague Solution-based protocols for OLED manufacture.

The team started with a layer of indium tin oxide and used light-activated chemistry to pinpoint specific locations on the surface for polymer growth. Key to the success of this approach are designer iridium photocatalysts that serve two roles: First, as the catalyst to build the emissive brush polymers, and then as a necessary dopant for the resulting OLED arrays.