Team makes breakthrough in solar energy research

July 30, 2013 by Kenneth K Ma
Black metal samples with different nanostructures thickness and coated with aluminum laying over a high reflective flat aluminum surface.

The use of plasmonic black metals could someday provide a pathway to more efficient photovoltaics (PV) —- the use of solar panels containing photovoltaic solar cells —- to improve solar energy harvesting, according to researchers at Lawrence Livermore National Laboratory (LLNL).

The LLNL Materials Engineering Division (MED) research team has made breakthroughs experimenting with black metals. These nanostructured metals are designed to have low reflectivity and high absorption of visible and . The MED research team recently published their black metals research results in a cover-page article in the May issue of Applied Physics Letters titled "Plasmonic Black Metals in Resonant Nanocavities."

Authored by MED physicist and research team member Mihail Bora, the article details the work of the Nanophotonics and Plasmonics research team led by LLNL Engineer Tiziana Bond.

It describes the team's concept of black metals, which are not classic metals but can be thought of as an extension of the black silicon concept. When silicon is treated in a certain way, such as being roughened at the nanoscale level, it traps light by multiple reflections, increasing its solar absorption. This gives the silicon a black surface that's able to better trap the full sun's .

Similarly, black metals are produced by some sort of random nanostructuring—either in gold or silver—without guaranteeing a full, reliable and repeatable full solar absorption. However, Bond's team developed a method to improve and control the absorption efficiency and basically turn the metals as black as they want, allowing them to increase, on demand, the absorption of a higher quantity of solar wavelengths. Her team built nanopillar structures that are trapping and absorbing all the relevant wavelengths of the entire .

"Our article was picked for the cover story of Applied Physics Letters because it represents cutting-edge work in the area of plasmonics, the broadband operation obtained with a clear design and its implication for the photovoltaic (PV) yield," Bond said.

This new LLNL technology could one day be used in the energy harvesting industry such as PV. By incorporating metallic nanostructures with strong coupling of incident light, broad spectral and angular coverage, the LLNL team is providing a path for more efficient and thermovoltaics (a form of energy collection) by means of plasmon-exciton conversion, according to Bond and Bora.

Explore further: Imaging nanoporous metals with beams of electrons provides deep insights into unusual optical properties

More information: Paper:
The teams' black metal research will also be featured in the September issue of Nature Photonics.

Related Stories

Blackening copper opens new applications

January 16, 2013

(—Copper is one of the world's most widely used metals. Now researchers at the University of Dundee have found that blackening copper using industry-standard lasers could make it even more adaptable and efficient.

Scientists break record for thinnest light-absorber

July 18, 2013

Stanford University scientists have created the thinnest, most efficient absorber of visible light on record. The nanosize structure, thousands of times thinner than an ordinary sheet of paper, could lower the cost and improve ...

Recommended for you

Fusion reactors 'economically viable' say experts

October 2, 2015

Fusion reactors could become an economically viable means of generating electricity within a few decades, and policy makers should start planning to build them as a replacement for conventional nuclear power stations, according ...

Iron-gallium alloy shows promise as a power-generation device

September 29, 2015

An alloy first made nearly two decades ago by the U. S. Navy could provide an efficient new way to produce electricity. The material, dubbed Galfenol, consists of iron doped with the metal gallium. In new experiments, researchers ...

Extending a battery's lifetime with heat

October 1, 2015

Don't go sticking your electronic devices in a toaster oven just yet, but for a longer-lasting battery, you might someday heat them up when not in use. Over time, the electrodes inside a rechargeable battery cell can grow ...

Invisibility cloak might enhance efficiency of solar cells

September 30, 2015

Success of the energy turnaround will depend decisively on the extended use of renewable energy sources. However, their efficiency partly is much smaller than that of conventional energy sources. The efficiency of commercially ...

Scientists produce status check on quantum teleportation

September 30, 2015

Mention the word 'teleportation' and for many people it conjures up "Beam me up, Scottie" images of Captain James T Kirk. But in the last two decades quantum teleportation – transferring the quantum structure of an object ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

2.6 / 5 (5) Jul 30, 2013
Micrograph from paper:


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.