OLEDs - Page 6

In a pending Indiegogo crowd-funding project, Czech technology developers aim to use graphene's conductivity, flexibility and strength to make a smartwatch with estimated delivery is May 2015. While this project sounds intriguing, and Graphene-info's staff will be first in line for it if it comes out, this does sound a bit far fetched. 

The watch, called "uGear PeaClock", is currently in developement and will sport a cool futuristic look and all of the usual smartwatch abilities, including several unusual ones: a holographic keyboard projected onto any surface, graphene shifting body, 1080p HD OLED display and more. 

Researchers at the Swedish Umea University revealed that semiconducting polymers, placed on a layer of graphene, transport electrical charges more efficiently than when the same polymer is placed on a silicon substrate.

The researchers say that graphene enhances the charge transport through the polymer film, making it potentially useful for producing more efficient electronic devices like organic solar cells, OLEDs and more.

In June 2013, Cambridge University's Graphene Centre (CGC) and Plastic Logic started to develop a transparent graphene-based backplane for flexible displays. Now Plastic Logic demonstrated the first display that was developed in that collaboration research. Plastic Logic says that this is the first time graphene has been used in a transistor-based flexible device.

The prototype (shown above) is an active-matrix electrophoretic (E Ink) display fabricated on flexible plastic. The electrodes are made from solution-processed graphene which was patterned after deposition with micron-scale features. The prototype has a pixel density of 150 PPI and was made at low temperatures (less than 100 degrees celsius). This is just a prototype of course and you can see many defects in display.

Researchers from Philips, Graphenea and the University of Cambridge developed a monochrome OLED device that uses graphene as the transparent conductor layer. They report that the graphene-based TC outperforms that state-of-the-art ITO solutions currently used for OLED panels.

ITO is the most popular material for transparent conductors in displays and solar cells, but it is expensive, rare and brittle, and a lot of companies are developing alternatives - based on silver, carbon or other materials.

The University of Surrey in the UK is establishing a graphene center, within its Advanced Technology Institute (ATI). The Institute will extend its research into the uses and manufacture of graphene across such applications as high frequency electronics, flexible and transparent electronics, smart coatings and interconnect technology. The university is also interested in using graphene in solar cells, supercacitors, printed transistors and OLED displays.

The ATI developed Photo Thermal deposition technology that can deposit electronic grade graphene on wafer scale substrates. The tool performs catalyst deposition and graphene growth, allowing high volume production. The graphene center received more than £1.2 million (over $2 million) from the EPSRC, NPL and a range of industrial companies. Academic partners in the new center include the Universities of Cambridge, Oxford, Manchester, Imperial, Exeter, Trinity College Dublin and Aristotle University of Thessaloniki.

The Graphene Research Centre (GRC) at the National University of Singapore (NUS) and BASF announced a new partnership to develop the use of graphene in organic electronics devices - such as OLED devices. The goal of this collaboration is to interface graphene films with organic electronic materials, with an aim to create more efficient and flexible lighting devices.

In this collaboration, the GRC will contribute its graphene knowledge (the synthesis and characterization of the graphene) while BASF is focused on organic materials. Of course BASF is also engaged with graphene research (for several years) and are looking to speed up their device development with this new partnership.

The EU launched a new project called GLADIATOR (Graphene Layers: Production, Characterization and Integration) that aims to improve the quality and size of CVD graphene sheets and reduce the production cost.

GLADIATOR directly targets the transparent electrodes market and will demonstrate that ITO can be matched on performance (over 90% transparency and a resistance of less than 10 W/sq) and cost (under 30 €/m²). During the project, they will produce ultraviolet organic photodiodes and large area flexible OLEDs.

Researchers from Rice University created thin hybrid metal-graphene electrodes - that outperform ITO electrodes, are also more transparent and less resistance to electric current. These electrodes can be used to create non-glass touch displays, transparent and flexible OLEDs, solar cells and lighting products.

The new electrode is a thin film of single-layer graphene and a fine grid of metal nanowire. It's basically a hybrid-graphene electrode. The metal is used to enhance the conductivity at the required transparency. The metal grid strengthens the graphene, and the graphene fills all the empty spaces between the grid. The researchers found a grid of five-micron nanowires made of inexpensive, lightweight aluminum did not detract from the material's transparency.

Scientists from the National Physical Laboratory in New Delhi, India developed graphene based quantum dots (GQDs) blended with organic polymers that can be used in new photovoltaics (solar) cells. This may solve the problem of toxic metals (cadmium and lead) used in today's quantum dots, and the new material is also more stable then current organic materials.

The GQDs are 9-nm in size have similar electronic properties to normal QDs, and actually perform better (less current loss and improved efficiency) because of graphene's high charge carrier mobility. This work could lead to light-weight, flexible and cheap panels - used in large-area roll-to-roll manufacturing. In fact they say that these GQDs may also be used in other applications such as OLED displays, and indeed the team fabricated OLEDs using the new material - with "good performance".

Researchers at Stanford University have successfully developed a brand new concept of OLEDs with a few nanometer of graphene as transparent conductor. This paved the way for inexpensive mass production of OLEDs on large-area low-cost flexible plastic substrate, which could be rolled up like wallpaper and virtually applied to anywhere you want. The researchers say that Graphene has the potential to be transparent, high-performance, highly conductive and cheaper by several orders of magnitude than current ITO based solutions.

Graphene OLED

Traditionally, indium tin oxide (ITO) is used in OLEDs, but indium is rare, expensive and difficult to recycle. Scientists have been actively searching for an alternative candidate.