Boffins promise caffeine boost for energy-efficient TVs

Inspired by the ring-shaped stains left by spilled coffee, scientists have developed a more efficient technique for making the ultra-thin coatings used on the screens of energy-efficient LCD and plasma TVs.

According to reports in this week's New Scientist, a team at the Institute of Chemical and Engineering Sciences in Singapore has pioneered a new technique for applying the transparent conductive coatings, which are used by LCD screens to create an electrode on the screen surface and by plasma screens to prevent electromagnetic fields from straying.

Traditionally, these coating are made using an expensive technique involving vacuum chambers known as sputtering that applies a fine layer of indium tin oxide (ITO) to the screen.

However, the Singapore team believes that the same principles of evaporation that create unsightly coffee rings could underpin an approach that offers a significantly cheaper alternative.

Ivan Vakarelski, who led the research team, found that when coffee is spilled, varying evaporation and convection rates of the liquid "assemble" the coffee granules in a circle underneath the cup.

Vakarelski and his team concluded that the same process could be replicated to control the pattern of granules to form a nanoscale conductive coating without resorting to expensive vacuum systems.

The team successfully applied the technique to gold particles, each about 20 nanometres across and suspended in water. The liquid was left to dry on a glass plate covered with latex microspheres, while the team lowered the temperature to control the rate of evaporation and convection. The process resulted in a network of connected gold nanoparticles that adhered to the intended pattern.

"Our gold network is finer than spider's silk and is also conductive," Vakarelski told the New Scientist, adding that gold could make even better conductors than ITO coatings.

He also argued that the process would be relatively easy to scale up to mass-production levels, making it a viable alternative to existing techniques.