MMaterialsgateNEWS 2014/09/17

Related MaterialsgateCARDS

'Squid skin' metamaterials project yields vivid color display

Rice lab creates RGB color display technology with aluminum nanorods

The quest to create artificial "squid skin" -- camouflaging metamaterials that can "see" colors and automatically blend into the background -- is one step closer to reality, thanks to a breakthrough color-display technology unveiled this week by Rice University's Laboratory for Nanophotonics (LANP).

The new full-color 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 technology is described in a new study that will be posted online this week in the Early Edition of the Proceedings of the National Academy of Sciences (PNAS).

The breakthrough is the latest in a string of recent discoveries by a Rice-led team 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.

"Our goal is to learn from these amazing animals so that we could create new materials with the same kind of distributed light-sensing and processing abilities that they appear to have in their skins," said LANP Director Naomi Halas, a co-author of the PNAS study. She is the principal investigator on a $6 million Office of Naval Research grant for a multi-institutional team that includes marine biologists Roger Hanlon of the Marine Biological Laboratory in Woods Hole, Mass., and Thomas Cronin of the University of Maryland, Baltimore County.

"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," Halas said.

LANP's new color 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 colors, 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 PNAS study. "The key advancement here was to place the nanorods in an ordered array."

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

"This arrangement allowed us to narrow the output spectrum to one individual color instead of the typical muted shades that are usually produced by aluminum nanoparticles," she said.

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 nanometers long by 40 nanometers wide. She used electron-beam deposition to create arrays -- regular arrangements of nanorods -- in each pixel.

She was able to fine-tune the color produced by each pixel by using theoretical calculations by Rice physicists Alejandro Manjavacas, a postdoctoral researcher, and Peter Nordlander, professor of physics and astronomy.

"Alejandro created a detailed model of the far-field plasmonic interactions between the nanorods," Olson said. "That proved very important because we could use that to dial in the colors very precisely."

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, polarizers and individually addressable pixels. The photonic aluminum arrays would be used in place of the colored dyes that are found in most commercial displays. Unlike dyes, the arrays won't fade or bleach after prolonged exposure to light, and the inherent directionality of the nanorods provides another advantage.

"Because the nanorods in each array are aligned in the same direction, our pixels produce polarized light," he said. "This means we can do away with one polarizer in our setup, and it also gives us an extra knob that we can use to tune the output from these arrays. It could be useful in a number of ways."

Link and Halas said they hope to further develop the display technology and eventually to combine it with other new technologies that the squid skin team has developed both for sensing light and for displaying patterns on large polymer sheets. For example, Halas and colleagues published a study in Advanced Materials in August about an aluminum-based CMOS-compatible photodetector technology for color sensing. In addition, University of Illinois at Urbana-Champaign co-principal investigator John Rogers and colleagues published a proof-of-concept study in PNAS in August about new methods for creating flexible black-and-white polymer displays that can change color to match their surroundings.

"We hope to eventually bring all of these technologies together to create a new material that can sense light in full color and react with full-color camouflage displays," Halas said.

Source: Rice University – 15.09.2014.

Investigated and edited by:

Dr.-Ing. Christoph Konetschny, Inhaber und Gründer von Materialsgate
Büro für Material- und Technologieberatung
The investigation and editing of this document was performed with best care and attention.
For the accuracy, validity, availability and applicability of the given information, we take no liability.
Please discuss the suitability concerning your specific application with the experts of the named company or organization.

You want additional material or technology investigations concerning this subject?

Materialsgate is leading in material consulting and material investigation.
Feel free to use our established consulting services

MMore on this topic

A flexible display incorporating graphene in its pixels’ electronics has been successfully demonstrated by the Cambridge Graphene Centre and Plastic Logic, the first time graphene has been used in a transistor-based flexible device.

The partnership between the two organisations combines the graphene expertise of the Cambridge Graphene Centre (CGC), with the transistor and display processing steps that Plastic Logic has already developed for flexible electronics. This prototype is a first example of how the partnership will accelerate the commercial development of graphene, and is a first step towards the wider implementation of graphene and graphene-like materials into flexible electronics. Graphene is a two-dimensional material made up of sheets of carbon atoms. It is among the strongest, most lightweight and flexible materials known, and has the potential to revolutionise industries from healthcare to electronics... more read more

What if computer screens had glasses instead of the people staring at the monitors? That concept is not too far afield from technology being developed by UC Berkeley computer and vision scientists.

The researchers are developing computer algorithms to compensate for an individual’s visual impairment, and creating vision-correcting displays that enable users to see text and images clearly without wearing eyeglasses or contact lenses. The technology could potentially help hundreds of millions of people who currently need corrective lenses to use their smartphones, tablets and computers. One common problem, for example, is presbyopia, a type of farsightedness in which the ability to focus on nearby objects is gradually diminished as the aging eyes’ lenses lose elasticity. More importantly, the displays could one day aid people with more complex visual problems, known as high order... more read more

If you’ve ever tried to watch a video on a tablet on a sunny day, you know you have to tilt it at just the right angle to get rid of glare or invest in a special filter.

But now scientists are reporting in the journal ACS Applied Materials & Interfaces that they’ve developed a novel glass surface that reduces both glare and reflection, which continue to plague even the best mobile displays today. Valerio Pruneri and colleagues note that much effort has been poured into anti-reflective and anti-glare technology. In the highly competitive digital age, any bonus feature on a device gives it an edge. But for the most part, that hasn’t included an integrated anti-glare, anti-reflective display. Users still typically have to dish out extra cash for a filter or film — some of questionable effectiveness — to lay on top of their glass screens so they... more read more

A new discovery will make it possible to create pixels just a few hundred nanometres across that could pave the way for extremely high-resolution and low-energy thin, flexible displays for applications such as 'smart' glasses, synthetic retinas, and foldable screens.

A team led by Oxford University scientists explored the link between the electrical and optical properties of phase change materials (materials that can change from an amorphous to a crystalline state). They found that by sandwiching a seven nanometre thick layer of a phase change material (GST) between two layers of a transparent electrode they could use a tiny current to 'draw' images within the sandwich 'stack'. Initially still images were created using an atomic force microscope but the team went on to demonstrate that such tiny 'stacks' can be turned into prototype pixel-like devices. These 'nano-pixels' – just 300 by 300 nanometres in size... more read more


Partner of the Week

Search in MaterialsgateNEWS

Books and products