Green Solar Panels And Other Colors

Researchers from AMOLF, the University of Amsterdam (UvA) and the Energy Research Centre of the Netherlands (ECN) have developed a technology to create efficient bright green colored solar panels. Arrays of silicon nanoparticles integrated in the front module glass of a silicon heterojunction solar cell scatter a narrow band of the solar spectrum and create a green appearance for a wide range of angles. The remainder of the solar spectrum is efficiently coupled into the solar cell. The current generated by the solar panel is only  reduced by 10%. The realization of efficient colorful solar panels is an important step for the integration of solar panels into the built environment and landscape.
research has much focused on maximizing the electricity yield obtained from solar panels: nowadays, commercial panels have a maximum conversion efficiency from sunlight into electricity of around 22%. To reach such high efficiency, silicon solar cells have been equipped with a textured surface with an antireflection layer to absorb as much light as possible. This creates a dark blue or black appearance of the solar panels.

To create the colored solar panels the researchers have used the effect of Mie scattering, the resonant backscattering of light with a particular color by nanoparticles. They integrated dense arrays of silicon nanocylinders with a diameter of 100 nm in the top module cover slide of a high-efficiency silicon heterojunction solar cell. Due to the resonant nature of the light scattering effect, only the green part of the spectrum is reflected; the other colors are fully coupled into the solar cell. The current generated by the mini solar panel (0,7 x 0,7 cm2)  is only reduced by 10%. The solar panel appears green over a broad range of angles up to 75 degrees. The nanoparticles are fabricated using soft-imprint lithography, a technique that can readily be scaled up to large-area fabrication.
The light scattering effect due to Mie resonances is easily controllable: by changing the size of the nanoparticles the wavelength of the resonant light scattering can be tuned. Following this principle the researchers are now working to realize solar cells in other colors, and on a combination of different colors to create solar panels with a white appearance. For the large-scale application of solar panels, it is essential that their color can be tailored.

The new design was published online in the journal Applied Physics Letters.


Solar Panels Reach 36.4 Percent Efficiency

Swiss start-up Insolight says its solar panels double the yield achieved by other sun-powered technology. In independent tests the panels reached an efficiency of 36.4 percent.


Traditionally the market sits at around 18 percent and we can double this. Therefore we can double the return on investment for the final client….Our key innovation is that you do not need to rotate the panel in order to follow the sun. We can follow the sun in a flat manner, like any other solar panel, which makes it that our panel can be installed on standard rooftops, with standard mounting technology,” says Florian Gerlich Co-Founder of Insolight company.

Tiny square super cells capture all of the sun’s rays, underneath round lenses, using a patented microtracking system. “Why micro? Why tracking? Micro is a really really small movement that is encapsulated into the solar panel and tracking is to track the sun to concentrate the light into our really tiny solar cell,” comments Noe Bory from Insolight.  An injection-moulded transparent plate moves one centimetre throughout the day, a small sensor detecting the sun’s position.

“As you see here the small squares spread out over the whole surface and under each of these lenses there is a small solar cell. It’s a bit like the lenses that you’re using in your reading lenses or your reading glasses. It’s the same technology, it’s just a particular shape in order to be able to follow the sun from morning to the evening,” adds Florian Gerlich.

The panels may be more expensive to buy than current technology. But Insolight says energy prices will be slashed from 14 US cents per kilowatt hour to 9 cents. A large bed of panels will be tested in Lausanne this summer. Insolight says the system could be market-ready next year.

Black Silicon Solar Cells Efficiency Jump

Researchers from Aalto University (Finland) together with colleagues from Universitat Politècnica de Catalunya (Spain) have obtained the record-breaking efficiency of 22.1% on nanostructured silicon solar cells as certified by Fraunhofer ISE CalLab. An almost 4% absolute increase to their previous record is achieved by applying a thin passivating film on the nanostructures by Atomic Layer Deposition, and by integrating all metal contacts on the back side of the cell.black_silicon_solar_cell_hele_savin_aalto_university_en

The surface recombination has long been the bottleneck of black silicon solar cells and has so far limited the cell efficiencies to only modest values. The new record cells consists of a thick back-contacted structure that is known to be highly sensitive to the front surface recombination. The certified external quantum efficiency of 96% at 300nm wavelength demonstrates that the increased surface recombination problem no longer exists and for the first time the black silicon is not limiting the final energy conversion efficiency. The energy conversion efficiency is not the only parameter that we should look at, explains Professor Hele Savin from Aalto University, who coordinated the study. Due to the ability of black cells to capture solar radiation from low angles, they generate more electricity already over the duration of one day as compared to the traditional cells.

The results were published online 18.5.2015 in Nature Nanotechnology.

How To Produce Massively And Easily Solar Panels

Nanoscale materials feature extraordinary, billionth-of-a-meter qualities that transform everything from energy generation to data storage. But while a nanostructured solar cell may be fantastically efficient, that precision is notoriously difficult to achieve on industrial scales. The solution may be self-assembly, or training molecules to stitch themselves together into high-performing configurations.

Now, scientists at the U.S. Department of Energy’s Brookhaven National Laboratory have developed a laser-based technique to execute nanoscale self-assembly with unprecedented ease and efficiency.

solarPanelWe design materials that build themselves,” said Kevin Yager, a scientist at Brookhaven’s Center for Functional Nanomaterials (CFN). “Under the right conditions, molecules will naturally snap into a perfect configuration. The challenge is giving these nanomaterials the kick they need: the hotter they are, the faster they move around and settle into the desired formation. We used lasers to crank up the heat.”


Send Men Above Venus, NASA ‘s New Dream

To send an astronauts team around Venus is easier than to Mars. Why? Mainly because Venus is much closer to the Sun and due to continuous progress in the solar panel technology, any spaceship will benefit from an inexhaustible source of solar energy. The atmosphere of Venus is, as well, an exciting destination for both further scientific study and future human exploration. A lighter-than-air vehicle can carry either a host of instruments and probes, or a habitat and ascent vehicle for a crew of two astronauts to explore Venus for up to a month. The mission requires less time to complete than a crewed Mars mission, and the environment at 50 km is relatively benign, with similar pressure, density, gravity, and radiation protection to the surface of Earth. A recent internal NASA study of a High Altitude Venus Operational Concept (HAVOC) led to the development of an evolutionary program for the exploration of Venus, with focus on the mission architecture and vehicle concept for a 30 day crewed mission into Venus’s atmosphere.
NASA_HAVOCKey technical challenges for the mission include performing the aerocapture maneuvers at Venus and Earth, inserting and inflating the airship at Venus, and protecting the solar panels and structure from the sulfuric acid in the atmosphere. With advances in technology and further refinement of the concept, missions to the Venusian atmosphere can expand humanity’s future in space.


Cheap Hydrogen Fuel

The race is on to optimize solar energy’s performance. More efficient silicon photovoltaic panels, dye-sensitized solar cells, concentrated cells and thermodynamic solar plants all pursue the same goal: to produce a maximum amount of electrons from sunlight. Those electrons can then be converted into electricity to turn on lights and power your refrigerator.
hydrogen-electric car At the Laboratory of Photonics and Interfaces from Ecole Polytechnique Fédérale de Lausanne (EPFL) – Switzerland -, led by Michael Grätzel, where scientists invented dye solar cells that mimic photosynthesis in plants, they have also developed methods for generating fuels such as hydrogen through solar water splitting. To do this, they either use photoelectrochemical cells that directly split water into hydrogen and oxygen when exposed to sunlight, or they combine electricity-generating cells with an electrolyzer that separates the water molecules.

By using the latter technique, Grätzel’s post-doctoral student Jingshan Luo and his colleagues were able to obtain a performance spectacular: their device converts into hydrogen 12.3 percent of the energy diffused by the sun on perovskite absorbers – a compound that can be obtained in the laboratory from common materials, such as those used in conventional car batteries, eliminating the need for rare-earth metals in the production of usable hydrogen fuel. This high efficiency provides stiff competition for other techniques used to convert solar energy. But this method has several advantages over others:
Both the perovskite used in the cells and the nickel and iron catalysts making up the electrodes require resources that are abundant on Earth and that are also cheap,” explained Jingshan Luo. “However, our electrodes work just as well as the expensive platinum-based models customarily used.”
The research is being published today in the journal Science.

How To Turn ANYTHING Into A Solar Panel

A team of scientists at the University of Sheffield  (U.K.) is the first to fabricate perovskite solar cells using a spray-painting process – a discovery that could help cut the cost of solar electricity.  
Efficient organometal halide perovskite based photovoltaics were first demonstrated in 2012. They are now a very promising new material for solar cells as they combine high efficiency with low materials costs. The spray-painting process wastes very little of the perovskite material and can be scaled to high volume manufacturing – similar to applying paint to cars and graphic printing.

perovskite solar panel

Remarkably, this class of material offers the potential to combine the high performance of mature solar cell technologies with the low embedded energy costs of production of organic photovoltaics“, said  lead researcher Professor David Lidzey.” While most solar cells are manufactured using energy intensive materials like silicon, perovskites, by comparison, requires much less energy to make. By spray-painting the perovskite layer in air the team hope the overall energy used to make a solar cell can be reduced further”. “The best certified efficiencies from organic solar cells are around 10 per cent. “Perovskite cells now have efficiencies of up to 19 per cent. This is not so far behind that of silicon at 25 per cent – the material that dominates the world-wide solar market” , he added.


Ninety Nine Percent Of Sunlight May Be Source To Electricity

Rice University scientists have created a one-step process for producing highly efficient materials that let the maximum amount of sunlight reach a solar cell. The Rice lab of chemist Andrew Barron found a simple way to etch nanoscale spikes into silicon that allows more than 99 percent of sunlight to reach the cells’ active elements, where it can be turned into electricity. The more light absorbed by a solar panel’s active elements, the more power it will produce. But the light has to get there. Coatings in current use that protect the active elements let most light pass but reflect some as well. Various strategies have cut reflectance down to about 6 percent, Barron said, but the anti-reflection is limited to a specific range of light, incident angle and wavelength.

Enter black silicon, so named because it reflects almost no light. Black silicon is simply silicon with a highly textured surface of nanoscale spikes or pores that are smaller than the wavelength of light. The texture allows the efficient collection of light from any angle — from sunrise to sunset

Barron and Lu have replaced a two-step process that involved metal deposition and electroless chemical etching with a single step that works at room temperature.

The research by Barron and Rice graduate student and lead author Yen-Tien Lu appears in the Royal Society of Chemistry’s Journal of Materials Chemistry A.

Multicolored Solar Panels

Until now, designers of buildings have no choice but to use black or bluish-gray colored solar panels. With the help of thin-film technologies, researchers have now been able to turn solar cells into colorful creations.
Covering a roof or a façade with standard solar cells to generate electricity will change a building’s original appearance – and not always for the better. At present only dark solar panels are widely available on the market.
But things are changing. The physicist Kevin Füchsel, project manager at the Fraunhofer Institute for Applied Optics and Precision Engineering IOF in Jena.- Germany – has been focusing for the last four years on nanostructured solar cells suitable for mass production as part of a junior research group funded by Germany’s Federal Ministry for Education and Research (BMBF). Together with a Fraunhofer team and scientists from the Friedrich-Schiller University in Jena, the group of optics specialists is looking for cost-effective techniques and manufacturing processes to increase both the efficiency of solar panels and the design flexibility they give architects and designers.
colorful solar panels

Not enough work has been done so far on combining photovoltaics and design elements to really do the term ‘customized photovoltaics’ justice,” says Kevin Füchsel. project manager at the Fraunhofer Institute for Applied Optics and Precision Engineering IOF in Jena.


Graphene Is The Solar Cells Future

Semiconductors grown on graphene at the Norwegian University of Science and Technology (NTNU) may be an important research breakthrough. At the centre of the research efforts are Professor Helge Weman, Professor Bjørn-Ove Fimland and post-doctoral fellow Dong-Chul Kim. The team is now working on translating the results of their basic research into an initial prototype. “Solar cell and LED technology will be the initial areas to see new products using semiconductors grown on graphene,” Dr Weman believes.

Under-priced fossil-fuel energy is the primary contributor to global warming. Sunlight is an alternative source with enormous potential, but solar energy will have to become less expensive and more efficient. Semiconductor nanowires based on graphene may just finally tip the scales in favour of solar energy.
graphene solar cells
If semiconductor nanowires grown on graphene are used in solar cells, the same amount of sunlight can be converted to energy using one-tenth the volume of materials used in thin-film solar cells. And that means we’ve cut down on even more material by growing the semiconductors on graphene instead of on a thick semiconductor substrate. New research also shows that graphene has additional unique properties that enhance the efficiency of a solar cell,” Dr Weman explains.“We are pioneers in that we are using graphene for something other than basic research. We may already have our first prototype in place by the end of 2013, but we don’t wish to reveal what it is yet,” Dr Weman says. “The field we are working with – using graphene as a replacement for silicon and other semiconductor substrates in electronics and solar cells – entails many new opportunities“.


Electric Car New Battery 10 times More Powerful

Los Alamos National Laboratory scientists have designed a new type of nanostructured-carbon-based catalyst that could pave the way for reliable, economical next-generation batteries and alkaline fuel cells, providing for practical use of wind– and solar-powered electricity, as well as enhanced hybrid electric vehicles. Los Alamos researchers Hoon T. Chung, Piotr Zelenay and Jong H. Won, the latter now at the Korea Basic Science Institute, describe a new type of nitrogen-doped carbon-nanotube catalyst. The new material has the highest oxygen reduction reaction (ORR) activity in alkaline media of any non-precious metal catalyst developed to date. This activity is critical for efficient storage of electrical energy. The new catalyst doesn’t use precious metals such as platinum, which is more expensive per ounce than gold, yet it performs under certain conditions as effectively as many well-known and prohibitively expensive precious-metal catalysts developed for battery and fuel-cell use. Moreover, although the catalyst is based on nitrogen-containing carbon nanotubes, it does not require the tedious, toxic and costly processing that is usually required when converting such materials for catalytic use.

These findings could help forge a path between nanostructured-carbon-based materials and alkaline fuel cells, metal-air batteries and certain electrolyzers,” said Zelenay. “A lithium-air secondary battery, potentially the most-promising metal-air battery known, has an energy storage potential that is 10 times greater than a state-of-the-art lithium-ion battery. Consequently, the new catalyst makes possible the creation of economical lithium-air batteries that could power electric vehicles, or provide efficient, reliable energy storage for intermittent sources of green energy, such as windmills or solar panels.

The research hax been published in a paper appearing recently in Nature Communications.


Black Silicon Solar Cells With 20% Efficiency

Scientists at Aalto University, Finland and Fraunhofer ISE, Germany report an efficiency of 18.7% for black silicon solar cells, the highest efficiency reported so far for a black silicon solar cell.
The researchers were able to apply a boron diffusion to create a pn-junction, maintaining the excellent optical properties of the black silicon structure. By applying atomic layer deposited Al203, an effective passivation of the nanostructured surfaces was achieved. The previous efficiency record of 18.2% was held by the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) using thermal oxidation as a passivating layer.

black silicon solar cells

The quantum efficiency measurements reveal that the nanostructured front surface is of a high electrical quality comparable to a pyramidal textured surface”, says Assistant Professor Hele Savin of Aalto University.
Routes for improving the cell efficiency are already identified, and efficiencies clearly above 20% should be within reach.