Then regular solar energy: antenna made carbon nanotubes could make solar cells more efficient

ScienceDaily (Sept. 13, 2010) - with carbon nanotubes (hollow tubes carbon atoms), more than one regular photovoltaic cell found with chemical engineers, to concentrate solar energy 100 times a way. Make such nanotubes could antennas that capture and could potentially allow light energy to focus much smaller and more powerful solar arrays.

Rather than your whole roof a photovoltaic cell, could little spots must you tiny photovoltaic cells, with antennas the photons in you were, would go, says Michael Strano, Charles and Hilda Roddey Associate Professor of chemical engineering and Director of the research team.

Strano and his students describe their new carbon nanotube antenna or "solar funnel," in the Sept. 12 online issue of the journal nature are Materials.Lead authors of the paper postdoctoral associate Jae-Hee Han and graduate student Geraldine Paulus.

Your new antennas may be also useful required goggles or telescopes for another application that focuses light, such as night vision.

Solar panels generate electricity by photons (packets of light energy) in electric current transform. Strano's nanotube antenna increases the number of photons can be captured and turned the light into energy, which be channelled in a solar cell.

The antenna consists of a fibrous rope 10 microns (1,000,000th meters) long and four microns thick, with about 30 million - carbon - nanotubes. Strano's team built, for the first time made a fiber from two layers of nanotubes with different electrical property-specifically, various Bandgaps.

Electrons at different energy levels can exist in any material. When a photon hits the surface, it attracts an electron to a higher energy level, which is specific to the material. The interaction between the energized electron and hole leaves it means an exciton and the difference in energy levels between the hole and the electron is known as the energy gap.

The inner layer of the antenna contains nanotubes with a small energy ratio and nanotubes in the outer layer have a higher energy pitch.This is important, because Exzitonenbildung like flow of high to low energy. In this case means that the Exzitonenbildung in the outer layer River on the inner level where they can be present in a lower (but still excited) power state.

Therefore, if strikes, light energy material are all in the middle of fiber where you focused the Exzitonenbildung.Strano and his team have not built yet a photovoltaic device with the antenna, but you want.In such a device, the antenna would focus photons before the photovoltaic cell could in an electric current konvertiert.Dies from the antenna to create a core of semiconducting material.

The interface between the semiconductor and the nanotubes would the electron from the hole with electrons at an electrode touching the inner semiconductor collected and the nanotubes trennen.Dieses covered holes that touch on an electrode system would then electricity animations.the materials for the electrode, according to the researchers would depend on the efficiency of a solar cell.

Strano's team is the first to construct nanotube fibres in which you can control the properties of the different layers, an achievement, made possible by recent advances in the separation of nanotubes with different properties.

While the cost of carbon nanotubes was once prohibitive, it has in recent years down been build as their production companies."" Sometime in the near future, probably for a few pennies per pound, carbon nanotubes are sold how polymers are sold,"says Strano.""With these costs, which in addition could be negligible costs of the cell to a solar cell compared to manufacturing and raw material, as coatings and polymer components are small components of the costs of a photovoltaic cell."

Strano's team now works on ways to minimize the energy lost as Exzitonenbildung flow through the fiber and opportunities, more than an Exciton per photon to generieren.Die nanotube bundle that lose material paper described around in the nature 13 percent of the energy you record, but the team is working on new antennas that would lose only 1 percent.

Funding: Career award of the National Science Foundation, MIT Sloan fellow, MIT DuPont Alliance and the Korea Research Foundation.

Story source:

The above story is from materials available provided by Massachusetts Institute of technology (with editorial adjustments of ScienceDaily staff) abgedruckt.Der original article was written by Anne Trafton, MIT News Office.

Journal reference:

Jae-Hee Han, Geraldine L. C. Paulus, Ryuichiro Maruyama, Daniel A. Heller, Woo-Jae Kim, Paul W. barons, Chang young Lee, Jong Hyun Choi, Moon Ho ham, Changsik song, C. Fantini, Michael S. Strano.Exciton antennas and concentrators core-shell and corrugated board carbon nanotube filaments of homogeneous composition.Natur materials, 2010; DOI: online nmat2832

Note: If no author is specified, instead cites the source.

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