Transparency - Page 2

Researchers at the Center for Multidimensional Carbon Materials (CMCM) within the Institute for Basic Science (IBS), have demonstrated a graphene coating that protects glass from corrosion. Their research has been said to hold potential for solving problems related to glass corrosion in several industries.

The IBS scientists grew graphene on copper and transferred either one or two atom-thick layers of graphene onto both sides of rectangular pieces of glass. The effectiveness of the graphene coating was evaluated by water immersion testing and observing the differences between uncoated and coated glass. After 120 days of immersion in water at 60 C, uncoated glass samples had significantly increased in surface roughness and defects, and reduced in fracture strength. In contrast, both the single and double layer graphene-coated glasses had essentially no change in both fracture strength and surface roughness.

Scientists at the University of WisconsinMadison have looked into graphene-based microelectrocorticography (uECoG) arrays, used in neuroscience researcher, searching for possibilities to expand the use of the arrays in areas such as the research of stroke or epilepsy. Researchers at the University of Wisconsin-Milwaukee, Medtronic PLC Neuromodulation, the University of Washington, and Mahidol University in Bangkok, Thailand were also involved in this study.

The researchers see graphene as one of the most promising candidates for transparent neural electrodes, because the material has a UV to IR transparency of more than 90%, in addition to its high electrical and thermal conductivity, flexibility, and biocompatibility. That allows for simultaneous high-resolution imaging and optogenetic control, according to the team.

Researchers from Korea's KAIST institute developed a rollable OLED device that uses graphene-based electrodes. The researchers say that the new OLED is much more durable when bent compared to current devices made with ITO electrodes.

The electrodes were made from a stack of materials - titanium oxdies, graphene and conductive polymers. The new OLEDs were also brighter than current devices, and with a higher color gamut. This was achieved by maximizing the resonance within the OLED.

The OLED Association, a trade group that promotes OLED technologies, published an interesting article in which they give predictions for the OLED market. The Association sees Samsung returning to the OLED TV market in 2017, and those upcoming OLED TVs will use several new technologies - including graphene-based transparent electrodes.

Last month we reported that researchers at Korea's ETRI developed transparent graphene-based electrodes for OLED panels. The researchers say that these new electrodes improve the transparency and "image quality" of OLEDs by 40 to 60 percent, compared to current silver-based electrodes. The researchers aim to continue the research and improve the performance of their electrodes.

Researchers at Korea's ETRI (Electronics and Telecommunications Research Institute) developed transparent graphene-based electrodes for OLED panels. The researchers say that these new electrodes improve the transparency and "image quality" of OLEDs by 40 to 60 percent, compared to current silver-based electrodes.

The researchers explain that current metal (mostly silver) based electrodes have a limited viewing angle because of their internal light reflection, and the external light reflection affects the image quality. Graphene electrodes are more transparent and reduce the reflectance by 40-60 percent.

The Centre of Process Innovation (CPI) has announced that it will be part of a UK-based collaboration to develop the next generation of graphene-based ultra-barrier materials for flexible transparent plastic electronic based displays. The materials on which this work focuses on are required for the next generation of smartphones, tablets and wearable electronics and the twelve month project titled ‘Gravia’ will investigate the feasibility of producing graphene-based barrier films for next generation flexible OLED lighting and display products. 

The project combines the skills from each of the partners (University of Cambridge, FlexEnable Ltd, the National Physical Laboratory and the Centre for Process Innovation) and expects to deliver a feasible material and process system. It builds upon significant existing investments by InnovateUK and the EPSRC in this area. The resulting ultra-barrier material can be potentially used in a wide range of novel applications by the lead business partner, FlexEnable.

A few days ago we reported that the Fraunhofer Institute FEP will demonstrate an OLED device with a graphene-based electrode, as part of project GLADIATOR. The researchers hope that the graphene will enable devices that are highly flexible and stable. The CVD-produced monolayer graphene was produced by Graphenea, and the project that will run until April 2017 aims to produce larger demonstrators.

We had the good chance of talking to Beatrice Beyer, the project's coordinator at the Fraunhofer Institute, and she was kind enough to answer a few questions we had regarding the project and the technology they develop.

Q: Beatrice, thanks for your time. Can you explain to us how the graphene compares to ITO as an OLED electrode?

For the time being, the optoelectronic performance of graphene as a transparent electrode is still not as good as for the mature 'industry standard' ITO, but the performance and production technologies are continuously improving and we are optimistic that soon graphene based devices will reliably compete with ITO based on performance.

As part of project GLADIATOR, The Fraunhofer Institute FEP will show an innovative organic light emitting diodes (OLEDs) with a graphene-based electrode at Plastic Electronics 2015. The fabricated OLED on transparent graphene electrodes has been realized on a small area, and the target of the next one and a half years of the project is to successfully achieve large area OLEDs.

With graphene as an electrode, the researchers at the Fraunhofer FEP hope for flexible devices with higher stability. The electrode contains CVD-produced monolayer graphene of high quality, supplied by Graphenea, in order to compete with the reference material ITO (which graphene, in this case, replaces), the transparency and conductivity of graphene must be very high. Therefore, not only the process of electrode manufacturing is being optimized, but also different ways of doping graphene to improve its properties are being examined.

Researchers from the University of Exeter have designed a new method to produce graphene significantly cheaper and easier than previously production methods. The researchers claim that this high-quality, low cost graphene could pave the way for the development of the first truly flexible 'electronic skin', that could be used in robots.

The new method grows graphene in an industrial cold wall CVD system, a state-of-the-art piece of equipment recently developed by UK graphene company Moorfield. This nanoCVD system is based on a concept already used for other manufacturing purposes in the semiconductor industry. This new technique is said to grow graphene 100 times faster than conventional methods, reduce costs by 99% and have enhanced electronic quality. The research team used this new technique to create the first transparent and flexible touch-sensor that could enable the development of artificial skin for use in robot manufacturing as well as flexible electronics. 

A team of scientists from Columbia, Seoul National University (SNU), and Korea Research Institute of Standards and Science (KRISS) reported the creation of an on-chip visible light source using graphene as a filament. Creating light in small structures on the surface of a chip is crucial for developing fully integrated 'photonic' circuits that do with light what is now done with electric currents in semiconductor integrated circuits.

The scientists attached small strips of graphene to metal electrodes, suspended the strips above the substrate, and passed a current through the filaments to cause them to heat up. The team refers to this design as 'the world's thinnest light bulb', a type of 'broadband' light emitter that can be integrated into chips and may pave the way towards the realization of atomically thin, flexible, and transparent displays, and graphene-based on-chip optical communications.