Saturday, 14 April 2012

The World First Transparent Loudspeakers Made Out of Graphene


We all know that graphite is a soft, black carbon mineral that conducts electricity. It is composed of many layers of sheets that look like the atomic-scale equivalent of a chicken wire or a honeycomb. Each of these stacked sheets is called graphene.

Recently, Korean researchers Keun-Young Shin, Jin-Yong Hong and Jyongsik Jang used graphene to create loudspeakers by using a simple four-step process. Using the same method previously developed by other researchers, the team synthesized Graphene Oxide (GO). They then utilized sound waves to exofoliate the GO in water which was then flushed with more water to wash away impurities. This produced graphene “ink” which the researchers then deposited inside an emptied and thoroughly cleaned inkjet printer cartridge.

Next, the researchers needed a surface/material on which to print the graphene ink. They manufactured the material they needed by treating the surface of a piece of Poly (vinylidene fluoride), or PVDF, with low temperature, oxygen plasma.

Using a commercial inkjet printer, the graphene ink was printed repeatedly on both sides of the treated PVDF to create graphene electrodes. The resulting product was then immersed in a solution of hydrazine and ammonia for three minutes; this was done in a vacuum. The sheet was then hooked up to acoustic electronic parts so that the graphene speakers can generate a piezoelectric effect which, in turn, creates sound waves.

The process was not only straightforward but also only used readily available materials. As a result, the graphene speakers that were developed did not produce great sound quality and the research team is continuing to improve their method and product. The Korean researchers said that their product is not yet ready to be made available to the market as it still leaves a lot to be desired in terms of sound quality.

Once perfected, the lightweight and extremely thin loudspeakers can be attached to a computer screen or a window, according to the researchers.

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