Nanotubes Stand Ready to Save Your Smartphone Display
A rare metal called indium used in smartphones, TV displays and solar cells has become endangered due to shrinking supplies, but an eco-friendly substitute stands ready to take its place.
Such timely intervention comes as available supplies of indium are expected to become exhausted within the next decade. The rare metal replacement is a transparent, electrically-conducting film based on tiny carbon nanotubes and plastic nanoparticles. [Energy-Critical Elements to Watch ]
The new film still has 100 times less conductivity than that of indium tin oxide. But researchers said that they could quickly boost the conductivity by using more metallic conducting nanotubes, as opposed to their initial batch of metallic and semiconducting nanotubes.
"[As] soon as you start to use 100 percent metallic tubes, the conductivity increases greatly," said Cor Koning, a polymer chemist at Eindhoven University of Technology in the Netherlands. "The production technology for 100 percent metallic tubes has just been developed, and we expect the price to fall rapidly."
The nanoscale objects in the film range in size from 1 and 100 nanometers. By comparison, a human hair is about 100,000 nanometers wide.
As it stands, the film is already good enough to serve as an antistatic layer for displays, or as shielding to protect devices from electromagnetic radiation.
The recipe for the new material requires a hodgepodge of nanotubes dissolved in water, latex made from polymer beads in water, and polystyrene beads. When heated, the polystyrene beads fuse together to create a film that holds the conducting network of nanotubes and polymer beads.
More substitutes may be required for rare metals and minerals beyond indium. Many modern electronics and technologies rely upon a wide array of exotic elements spanning the periodic table , including the so-called rare earth minerals. Disruptions to any of those element supplies could have costly impacts for both manufacturers and consumers.
A recent study also suggested that recycling the rare metals and minerals found in existing gadgets may offer a temporary solution at least until next-generation materials become available.
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