Nanotechnology Can Make Computer Displays Light-weight and Flexible
Nanotechnology might change the physical form of laptops, cell phones, and TV displays. Could a laptop computer display unroll like a portable movie screen, or could you detach it from your laptop and attach it to the back of an airline seat with Velcro? Nanotech researchers think all that is possible…and more!
Nanowires lighten up LED displays
Researchers at the University of Michigan have demonstrated that they can use nanowires as electrodes in organic light emitting diode (OLED) displays, which makes it possible to manufacture larger and more flexible OLED displays.
One option to nanowire-enabled flexible OLED displays could be a very thin, low-power, high-resolution screen that uses nanotubes. Various companies have worked on such a display, called a nano-emissive display because the nanotubes emit electrons at each spot on the display that must be illuminated to form a picture.
This display actually works much like an old-fashioned television set but can provide laptops with very lightweight screens and fine enough resolution for a high-definition TV display.
Displays get flexible using nanotechnology
The display in your cell phone and computer includes layers of transparent, conductive material called indium tin oxide. These layers of indium tin oxide have two problems: this material is expensive, and it cracks if you flex it. To protect these layers, they’re mounted on a rigid glass substrate. Unfortunately, growing a film of indium tin oxide on a substrate involves an expensive vacuum deposition process.
The folks designing new electronic gadgets like the idea of flexible display screens. They think that, once the display screens become flexible enough, they can make gadgets such as flexible cell phones that can be rolled into the shape of a bracelet that you can wear around your wrist.
To satisfy the desire for flexible displays and reduced costs, researchers are investigating nanomaterials that are conductive, transparent, flexible, and less expensive to apply. Silver nanowires deposited on plastic sheets are a promising option because the silver provides electrical conductivity, has about the same optical properties of indium tin oxide anodes, and is flexible.
Another option that can achieve flexibility, electrical conductivity, and transparency is using sheets of metallic carbon nanotubes. These nanotube-based sheets are transparent because carbon nanotubes absorb infrared light rather than visible light. Carbon nanotubes can be bent, therefore these thin (about 50 nm thick according to one vendor) sheets of carbon nanotubes are ultra-flexible.
Carbon nanotubes are still fairly expensive because large-scale nanotube manufacturing facilities have only recently been built, so the material isn’t widely available. Also, to manufacture a highly conductive sheet, you need to separate metallic-type nanotubes from semiconductor-type nanotubes, a complication that adds to the cost.
A third option to get the desired flexibility is to use graphene. Like carbon nanotubes, graphene does not absorb visible light, does conduct electricity, and is flexible. Graphene is expensive, however, because methods to separate graphene sheets, which are only one atom thick, from graphite, were only discovered a few years ago. As a result, graphene is not yet manufactured in quantities that make it cost effective.
For the near future, silver nanowires will be the preferred method used to produce flexible display screens. As the cost of carbon nanotubes or graphene comes down, one of those materials may take the lead in the marketplace.