Sunlight funnel collects light from all directions

March 1, 2018 by Lisa Zyga, feature
Randomly oriented light-harvesting pigments (green) funnel the sun’s energy to other molecules (red) that all have the same orientation, which diret the energy onto a photoconversion device. Credit: Pieper et al. Published in Nature Communications

Researchers have designed a light-harvesting funnel that absorbs sunlight from any direction and concentrates it onto smaller areas, such as high-performance solar cells. By stacking multiple funnels, each tuned to a different wavelength of light, the researchers expect that it could be possible to convert the entire solar spectrum into electricity with high efficiency.

The scientists, led by Peter Jomo Walla at the University of Braunschweig in Germany, have published a paper on the light-harvesting funnels in a recent issue of Nature Communications.

Although other solar concentrators exist that collect the sun's energy from large areas and direct it onto smaller areas, these devices face certain limitations. For instance, they don't work well in the shade, instead requiring direct solar irradiation, and as a result they usually rely on active sun-tracking systems.

Nature has shown, however, that it's not impossible to design a solar collector that overcomes these limitations. In living organisms that use photosynthesis, hundreds of randomly oriented pigments absorb photons even from indirect light, and funnel the energy toward a photosynthetic reaction center. Each step in this process occurs with nearly 100% efficiency.

In the new study, the researchers modeled the new light-harvesting funnels on nature's design. The devices consist of a large number of randomly oriented "donor" pigments that can absorb light from nearly all incident angles, and funnel it onto a smaller number of "acceptor" molecules that are all oriented in a single direction in order to direct the light onto a photoconversion device. This concept can reduce the intrinsic losses of previous solar concentrators to below 10%.

"By minimizing intrinsic loss mechanisms of previous light concentrators, I believe we have found a concept and an affordable realization that can help lead to the more widespread use of precious high-performance photovoltaics," Walla told

In tests, the researchers demonstrated that the new solar concentrator absorbs approximately 99% of the incident light, with minimal losses due to reabsorption and reflection. The device also has a light redirection quantum efficiency of 80%, which the researchers note is the most important parameter as it depends on the particular wavelength of the photons.

In the future, the researchers expect that these devices can be stacked on top of each other, with each device containing different pigments corresponding to different spectral ranges of sunlight. As the device materials are affordable, a stacked structure could lead to a low-cost, efficient method of collecting the sun's energy from across the entire solar spectrum.

"The pigments used in our proof-of-principle study currently cover only the blue spectral range and are not stable enough for long-term exposure to sunlight," Walla said. "However, our concept allows for screening a multitude of additional stable pigments of different colors for their ability to act either as light-harvesters or -redirectors. We are very enthusiastic about finding further suitable pigments and stacked architectures to ultimately cover the entire solar spectrum with high efficiency."

Explore further: Tweaking quantum dots powers-up double-pane solar windows

More information: Alexander Pieper et al. "Biomimetic light-harvesting funnels for re-directioning of diffuse light." Nature Communications. DOI: 10.1038/s41467-018-03103-4

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1 / 5 (2) Mar 01, 2018
I hope this continues towards rapid production cycles and that it does not get bought up by a large corporate "entity" and buried away in a suppression bin. This is starting to happen on an increasing scale across the board.

4.3 / 5 (3) Mar 01, 2018
I hope this continues towards rapid production cycles and that it does not get bought up by a large corporate "entity" and buried away in a suppression bin. This is starting to happen on an increasing scale across the board.


It has always happened on a large scale across the board. Oil companies bought all the solar tech and buried it in the 40's. GM bought and scrapped the entire public transit system in LA in the 40's, also. There ought to be laws against destroying the public good for private short-term profit, but the legislators are owned by the corporations.
1 / 5 (1) Mar 01, 2018
Those secret inventions bought up, suppressed and secreted away in an Illuminati warehouse? Realistically display the craven nature of capitalists. And actually (accidentally, I'm sure) benefiting all of us.

It;s what I call the Espionage Quandary. Soviet spies stole truckloads of American technology and it resulted in bupkis for the Russian economy.

The stolen (i.e. purchased but no one wants to open that can of worms) info, had to go through extensive bureaucratic filters. Before being used. And denied if it would compete with mature industries.

Realize how handicapped we would be today with obsolete technology. Think of Coal Power, that survives only from all the taxpayer subsidies they receive,

All the propaganda the Carbon Lobby pumps out to prevent competition from new technology.

Guesstimates and speculative prototypes are not final retailed products. With today's new materials & processes, finally those devices are ready for market.
not rated yet Mar 02, 2018
@rwillisj, but in the case of the public transit system in LA, we had a fully mature, working system, that it now costs tens of billions of dollars to reinstall. And that is only necessary because the replacement (personal automobiles) is such a disastrously inadequate solution that leads to nothing but delays and high costs and death from pollution and accidents. There was no benefit to anyone but the automobile and oil companies. And I suppose the road construction companies.

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