Solar cells are a key technology in the drive toward cleaner energy production. Unfortunately, solar technology is not yet economically competitive and the cost of solar cells needs to be brought down.
Schematic illustration of a silicon solar cell (a-Si:H) sandwiched between aluminum (Al) and transparent indium tin oxide (ITO) electrical contacts. Aluminum nanoparticles on the top (gray) enhance the absorption of light.
One way to overcome this problem is to reduce the amount of expensive semiconductor material used, but thin-film solar cells tend to have lower performance compared with conventional solar cells. Yuriy Akimov and Wee Shing Koh at the A*STAR Institute of High Performance Computing, have now improved the light conversion efficiency of thin-film solar cells by depositing aluminum particles on the cell surface.
Metallic nanoparticles can direct light better into the solar cell and prevent light from escaping. In conventional ‘thick-film’ solar cells, the nanoparticles would have little effect because all the light is absorbed by the film due to its thickness. For thin films, however, the nanoparticles can make a big difference. Their scattering increases the duration the light stays in the film, bringing the total absorption of light up to a level comparable with that for conventional solar cells. ”The strategy allows us to reduce the production costs of solar cells by several times and makes photovoltaics more competitive with respect to other forms of power generation,” says Akimov.
The researchers modeled the light absorption efficiency of solar cells for various nanoparticle materials and sizes. In particular, they compared the properties of silver versus aluminum nanoparticles. In most studies on the subject, silver particles have been preferred. These have optical resonances in the visible part of the spectrum that are even better at focusing the light into the solar cell. Unfortunately, there is a tradeoff: the optical resonances also cause the absorption of light by the nanoparticles, which means the solar cell is less efficient.
In the case of silver, this resonance is right in the key part of the solar spectrum, so that light absorption is considerable. But not so for aluminum nanoparticles, where these resonances are outside the important part of the solar spectrum. Furthermore, the aluminum particles handle oxidation well and their properties change little with variations in shape and size. And more importantly, their scattering properties are robust in comparison with silver nanoparticles. “We found that nanoparticles made of aluminum perform better than those made of other metals in enhancing light trapping in thin-film solar cells,” says Akimov. “We believe aluminum particles can help make thin-film solar cells commercially viable.”
The A*STAR-affiliated researchers contributing to this research are from the Institute of High Performance Computing.
 Akimov, Y.A. & Koh, W.S. Design of plasmonic nanoparticles for efficient subwavelength light trapping in thin-film solar cells. Plasmonics. Published online: 22 Oct 2010 | DOI: 10.1007/s11468-010-9181-4
 Akimov, Y A. & Koh, W.S. Resonant and nonresonant plasmonic nanoparticle enhancement for thin-film silicon solar cells. Nanotechnology 21, 235201 (2010).
Stretchable biofuel cells extract energy from sweat to power wearable devices
22.08.2017 | University of California - San Diego
Laser sensor LAH-G1 - optical distance sensors with measurement value display
15.08.2017 | WayCon Positionsmesstechnik GmbH
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
22.08.2017 | Life Sciences
22.08.2017 | Life Sciences
22.08.2017 | Life Sciences