New in photovoltaics: Arc en Ciel cells!

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Physical sciences and nanotechnology
"Arc en Ciel" photovoltaic cells

At the University of Notre Dame, Indiana, a group of researchers led by Dr Prashant V. Kamat has developed photovoltaic cells by combining semiconductor quantum dots of different sizes and nanotubes TiO2 instead of semiconductors used conventionally, making them much more effective. The study, supported by the Office of Basic Energy Sciences of the Department of Energy is published in the Journal of the American Chemical Society.

Scientists use these quantum dots Cadmium Selenide (CdSe) semiconductor rather than other materials because they have the unique advantage to absorb certain wavelengths of light, depending on their size: smaller quantum dots the go absorb shorter wavelengths, the biggest will absorb longer. By combining several types of quantum dots CdSe, so researchers can create sensitive cells that absorb more light spectrum and are thus more effective. The team arranged these quantum dots ordered pattern on the surface of a nanometer-thick film, and have incorporated it in Titanium dioxide nanotubes (TiO2). Quantum dots absorb photons and generate electrons which are then transported by the nanotubes and collected by an electrode, thereby producing the photocurrent.

Besides the absorption of particular wavelengths, the researchers noticed that the size of the quantum dots has an influence on the performance, by experimenting with four types of these nanoparticles (between 2,3 and 3,7 nm of diameter, they exhibit absorption peaks at wavelengths between 505 and 580 nm). Smaller quantum dots can convert photons to electrons faster, while larger ones absorb a greater percentage of photons. The 3nm diameter quantum dots offer the best compromise. After the development of the first photovoltaic cell composed of different types of quantum dots, the researchers plan for the next steps of their research to create "rainbow" cells, by superimposing layers of quantum dots according to their size: on the outer layer, the smaller ones absorb blue, and red light (longer wavelength) passes through this layer to reach the inner layer made up of the larger quantum dots which absorb red, creating a gradient d 'rainbow' absorption, while combining the effects of rapid conversion of small quantum dots and high absorption rate of larger quantum dots.

Current silicon photosensitive cells have an efficiency of 15 to 20%, the rest is lost in heat. Kamat foresees greater efficiency with these new types of "rainbow" photovoltaic cells, which could easily exceed 30%.

source:
- Nanowerk news, 06 / 03 / 2008 - http://www.nanowerk.com/spotlight/spotid=4832.php
- Physorg, 07 / 03 / 2008 - http://www.physorg.com/news124111555.html

Editor: Alban de Lassus, deputy-phys.mst@consulfrance-houston.org

[Christophe]

Thank you for the info, I newsé: https://www.econologie.com/solaire-photo ... -3748.html

By cons nothing on the cost of this new technology ... if 10 times important than the classic interest is quite limited ...

[Remundo]

Yield progress, but not transcendent ...

Laboratory of Nano-Technology is not nearly out ... We need carbon nanotubes in connection with special metal nanostructures ... And in addition, small metal clusters must have specific sizes capture different wavelengths ...

Sorry, I'm skeptical!

[Capt_Maloche]

it takes unstable material to distribute e-

30% are fine, what price?

[Christophe]

The price is not for nothing that it is not mentioned ... it must be monstrous

I'm sorry but the large-scale generation of electricity by solar PV should drive forward right away (I think the field of PV or solar PV roofs in the individual) ... Just as related research (except for space or other very specific applications ...)

Pkoi I think that? Because it's been a while (30 years) is known to the thermodynamic solar electric with yields higher than 50% and we spend billions in these PV shit to crummy performance and questionable ROI... But mostly by abandoning electrosolar ... We talk about Perrier?

[PhL38]

To consult -> http://www.nanosolar.com (sorry, in English)

One of the major costs of photovoltaics is not in the materials, but in the production processes. It seems that Nanosolar has found ways to drastically lower costs by using the "roll-to-toll" printing technique common in printing newspapers, fabrics, wallpapers etc. One of the big problems with Nanosolar is that they apparently do not want to authorize third-party producers under license, but on the contrary to remain in control of their technology from end to end, which limits production capacities and therefore the possibility of distribution. large-scale products of their technique! javascript: emoticon (': /)

Hopefully this will change ...

A+
PhL

[Capt_Maloche]

The largest photovoltaic roof in Europe in France
With m54.000 2 of photovoltaic panels, the roof of a warehouse in Laudun Gard will become Europe's largest photovoltaic plant. Inaugurated in June, should produce 1.650.000 kWh per year, consuming almost 500 households. Detail...

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[Remundo]

Thank you Captain!

It seems they are installing flexible PV panels, I believe they are cheaper, but with lower efficiency (<10%). Finally, given the surface they have, it is certainly the best compromise between installation costs and performance.

It's still Christophe who will sulk

They would have done better to put PHRSD