In my last article we have gone through about the structure and properties of graphene. Now we are going to have a look at the futuristic screen which is transparent, flexible, and portable too. These new graphene screens are Indium free and developed through flexible electrodes Graphene screens are almost completely transparent, and are highly conductive and very strong.  

  

 

Researchers have created a flexible graphene sheet with silver electrodes printed on it (top) that can be used as a touch screen when connected to control software on a computer

Anyone with a smart phone or an iPad will tell you touch screens are the way of the future. But touch screens have some serious drawbacks, such as how expensive they are, not to mention easily breakable.

Graphene is a semi-metallic transistor. Simply put a transistor hold stateful information by switching from conductive to non-conductive. A one or a zero for example.

LET’S GET TO THE GIST:

          Flexible, see-through video screens may be the “killer app” that finally puts graphene — the highly touted single-atom-thick form of carbon — into the commercial spotlight once and for all. And this research was reported in the online edition of ACS Nano.

          The lab’s hybrid graphene film is a strong candidate to replace indium tin oxide (ITO), a commercial product widely used as a transparent, conductive coating. It’s the essential element in virtually all flat-panel displays, including touch screens on smart phones and iPads, and is part of organic light-emitting diodes (OLEDs) and solar cells.

Main point to be noted here is these graphene screens are highly conductive and strong where as ITO screens are likely to be broken easily.

A hybrid material that combines a fine aluminum mesh with a single-atom-thick layer of graphene outperforms materials common to current touch screens and solar cells.

IT’S DESIGN:

Using a roller, the graphene face can then be pressed against an adhesive polymer support and the copper etched away, leaving the graphene film attached to the polymer. The graphene can then be pressed against a final substrate – such as polyethylene terephthalate (PET) – again using rollers, and the polymer adhesive released by heating. Subsequent layers of graphene can then be added in a similar way.

The researchers used this technique to create a rectangular graphene film measuring 30 inches (76 cm) in the diagonal. The graphene was doped by treating with nitric acid and in this form the graphene sheet can act as a large, transparent electrode and was demonstrated to work in a touch screen device.

Typically, transparent electrodes used in such applications are made from indium tin oxides (ITO). The researchers say that the graphene electrode has better transparency and is tougher. ‘The price of indium has increased by a few times over the past decades and this will be more serious as markets for display and solar cells expand,’ says Ahn.’In addition, oxide materials like ITO are usually fragile and weak.’ Because of this, ITO-based touch screens have a finite life span, whereas, a graphene-based screen should last essentially forever.

Left: A transparent graphene film transferred on a 35-inch PET sheet. Right: A graphene-based touch screen panel connected to a computer.

Courtesy: science daily, new gadget, technology review, sciencemag, rsc.org

Posted by

Gopi Chand (MGIT ECE 4th year)

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