Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Silver nanocubes make super light absorbers

Microscopic metallic cubes could unleash the enormous potential of metamaterials to absorb light, leading to more efficient and cost-effective large-area absorbers for sensors or solar cells, Duke University researchers have found.

Metamaterials are man-made materials that have properties often absent in natural materials. They are constructed to provide exquisite control over the properties of waves, such as light. Creating these materials for visible light is still a technological challenge that has traditionally been achieved by lithography, in which metallic patterns are etched onto an inert material, much like an ink-jet printer.

These are nanocubes.
Credit: Cristian Ciraci

As effective as lithography has been in creating such structures, it does have a limitation – it is very expensive and thus difficult to scale up to the large surface areas required for many applications.

"Our new approach is more of a bottom-up process," said Cristian Ciracì, research scientist at Duke's Pratt School of Engineering. "It may allow us to create devices – such as efficient solar panels – that cover much larger areas. In our experiments, we demonstrated an extraordinarily simple method to achieve this."

The results of Ciracì and co-workers' experiments, which were conducted in the laboratory of senior researcher David R. Smith, William Bevan Professor of electrical and computer engineering at Duke, were published Dec. 6 in the journal Nature.

For many applications or devices, the key is the material's ability to control the absorption of electromagnetic waves. Metals, for example, can be highly reflective on their own, which may be beneficial for some applications, but for something like a solar cell, optimal light absorption is desired.

"However, metamaterials based on metallic elements are particularly efficient as absorbers because both the electrical and magnetic properties of the material can be controlled by how we design them," Ciracì said.

The new metamaterial developed by the Duke team has three major components – a thin layer of gold film coated with a nano-thin layer of an insulator, topped off with a dusting of millions of self-assembled nanocubes. In the current experiments, the nanocubes were fabricated out of silver.

"The nanocubes are literally scattered on the gold film and we can control the properties of the material by varying the geometry of the construct," Ciracì said. "The absorptivity of large surface areas can now be controlled using this method at scales out of reach of lithography."

While metals on their own tend to have reflective properties, the nanocubes act as tiny antennae that can cancel out the reflectance of the metal surface.S

"By combining different components of the metamaterial elements together into a single composite, more complicated reflectance spectra could be engineered, achieving a level of control needed in more exotic applications, such as dynamic inks," Ciracì said.

The research was supported by the Air Force Office of Scientific Research and by the Army Research Office's Multidisciplinary University Research Initiative (MURI).

The other members of the team were first author Antoine Moreau, Clermont University, France; Duke's Ryan Hill, Jack Mock, Benjamin Wiley and Ashutosh Chilkoti; and Qiang Wang from the Capital Normal University, Beijing.

"Controlled-reflectance surfaces with film-coupled colloidal nanoantennas," A. Moreau, C. Ciraci, J. Mock, R. Hill, Q. Wang, B. Wiley, and A. Chilkoti. Nature, 6 Dec., 201

Richard Merritt | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)

nachricht Finding the lightest superdeformed triaxial atomic nucleus
20.10.2016 | The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Resolving the mystery of preeclampsia

21.10.2016 | Health and Medicine

Stanford researchers create new special-purpose computer that may someday save us billions

21.10.2016 | Information Technology

From ancient fossils to future cars

21.10.2016 | Materials Sciences

More VideoLinks >>>