New colour-display technology developed

Researchers have created a revolutionary colour-display technology that may pave the way for camouflaging metamaterials that can 'see' colours and automatically blend into the background.

The new full-colour display technology uses aluminum nanoparticles to create the vivid red, blue and green hues found in today's top-of-the-line LCD televisions and monitors.

The breakthrough is the latest in a string of recent discoveries by a team led by Rice University's Laboratory for Nanophotonics (LANP) that set out in 2010 to create metamaterials capable of mimicking the camouflage abilities of cephalopods - the family of marine creatures that includes squid, octopus and cuttlefish.

'We know cephalopods have some of the same proteins in their skin that we have in our retinas, so part of our challenge, as engineers, is to build a material that can 'see' light the way their skin sees it, and another challenge is designing systems that can react and display vivid camouflage patterns,' said LANP Director Naomi Halas, a co-author of the study.

LANP's new colour display technology delivers bright red, blue and green hues from five-micron-square pixels that each contains several hundred aluminum nanorods.

By varying the length of the nanorods and the spacing between them, LANP researchers Stephan Link and Jana Olson showed they could create pixels that produced dozens of colours, including rich tones of red, green and blue that are comparable to those found in high-definition LCD displays.

'Aluminum is useful because it's compatible with microelectronic production methods, but until now the tones produced by plasmonic aluminum nanorods have been muted and washed out,' said Link, associate professor of chemistry at Rice and the lead researcher on the study.

'The key advancement here was to place the nanorods in an ordered array,' Link added.

Olson said the array setup allowed her to tune the pixel's colour in two ways, first by varying the length of the nanorods and second by adjusting the length of the spaces between nanorods.

Olson's five-micron-square pixels are about 40 times smaller than the pixels used in commercial LCD displays. To make the pixels, she used aluminum nanorods that each measured about 100 nanometres long by 40 nanometres wide.

She used electron-beam deposition to create arrays - regular arrangements of nanorods - in each pixel.

Halas and Link said the research team hopes to create an LCD display that uses many of the same components found in today's displays, including liquid crystals, polarisers and individually addressable pixels.

Researchers hope to further develop the display technology and eventually to combine it with other new technologies to create a new material that can sense light in full colour and react with full-colour camouflage displays.

The research was published in the journal Proceedings of the National Academy of Sciences (PNAS).