David Kirkpatrick

April 3, 2010

Plastic electronics may lower solar costs

Seems like a lot of news in solar cost reduction of late. In a related note, I’ve added a new link group to the sidebar — “Interesting blog topics” — and each link goes to a search for all my posts in that category. If you’re interested in solar news, that link is a great way to find everything I’ve covered in one spot.

From the link, the release:

PLASTIC ELECTRONICS COULD SLASH THE COST OF SOLAR PANELS

Posted Mar 30, 2010 By Chris Emery

A new technique developed by Princeton University engineers for producing electricity-conducting plastics could dramatically lower the cost of manufacturing solar panels.

By overcoming technical hurdles to producing plastics that are translucent, malleable and able to conduct electricity, the researchers have opened the door to broader use of the materials in a wide range of electrical devices.

With mounting concerns about global warming and energy demand, plastics could represent a low-cost alternative to indium tin oxide (ITO), an expensive conducting material currently used in solar panels, according to the researchers.

“Conductive polymers [plastics] have been around for a long time, but processing them to make something useful degraded their ability to conduct electricity,” said Yueh-Lin Loo, an associate professor of chemical engineering, who led the Princeton team. “We have figured out how to avoid this trade-off. We can shape the plastics into a useful form while maintaining high conductivity.”

A multi-institutional team reported on its new technique in a paper published online March 8 in the Proceedings of the National Academy of Sciences.

The area of research, known as “organic electronics” because plastics are carbon-based like living creatures, holds promise for producing new types of electronic devices and new ways of manufacturing existing technologies, but has been hampered by the mysterious loss of conductivity associated with moldable plastics.

“People didn’t understand what was happening,” said Loo, who co-wrote the paper. “We discovered that in making the polymers moldable, their structures are trapped in a rigid form, which prevented electrical current from traveling through them.”

Once they understood the underlying problem, Loo and her colleagues developed a way to relax the structure of the plastics by treating them with an acid after they were processed into the desired form.

Plastic transistor

Princeton researchers have developed a new way to manufacture electronic devices made of plastic, employing a process that allows the materials to be formed into useful shapes while maintaining their ability to conduct electricity. In the plastic transistor pictured here, the plastic is molded into interdigitated electrodes (orange) allowing current flow to and from the active channel (green). (Image: Loo Research Group)

Using the method, they were able to make a plastic transistor, a fundamental component of electronics that is used to amplify and switch electronic signals. They produced the electrodes of the transistor by printing the plastic onto a surface, a fast and cheap method similar to the way an ink-jet printer produces a pattern on a piece of paper.

Loo said the technique potentially could be scaled up for mass production presses akin to those used to print newspapers. “Being able to essentially paint on electronics is a big deal,” Loo said. “You could distribute the plastics in cartridges the way printer ink is sold, and you wouldn’t need exotic machines to print the patterns.”

By allowing plastic solar cells to be manufactured using low-cost printing techniques and by replacing ITO as the primary conducting material, the plastics the team developed hold potential for lowering the cost of solar panels.

Currently, the electricity generated by plastic solar cells is collected by a transparent metal conductor made of ITO. The conductor must be transparent so that sunlight can pass through it to the materials in solar cells that absorb the light energy.

A rare and pricey byproduct of mining, ITO had come under increasing demand for use in flat-screen televisions, mobile phones and other devices with display screens. “The cost of indium tin oxide is skyrocketing,” Loo said. “To bring down the costs of plastic solar cells, we need to find a replacement for ITO. Our conducting plastics allow sunlight to pass through them, making them a viable alternative.”

The researchers anticipate that the plastics also could replace expensive metals used in other electronic devices, such as flexible displays. In addition, the scientists are beginning to explore the use of the plastics in biomedical sensors that would display a certain color if a person had an infection. For instance, the plastics turn from yellow to green when exposed to nitric oxide, a chemical compound produced during ear infections in children.

If the devices could be produced at a low cost, they might be useful in developing countries that lack advanced medical facilities. “You wouldn’t need any fancy machines or lab equipment to diagnose an infection,” Loo said, “all you would need is your eyes to see the color change in the plastics.”

The co-authors of the paper were Joung Eun Yoo, who received her doctorate in chemical engineering from the University of Texas-Austin in 2009 with Loo as her adviser; Kimberly Baldwin, a high school student who spent a summer in Loo’s lab; Jacob Tarver, a Princeton chemical engineering graduate student; Enrique Gomez of Pennsylvania State University; Kwang Seok Lee and Yangming Sun of the University of Texas-Austin; Andres Garcia and Thuc-Quyen Nguyen of the University of California-Santa Barbara; and Hong Meng of DuPont Central Research and Development.

The research was supported by the National Science Foundation, the W.M. Keck Foundation and the Arnold and Mabel Beckman Foundation.

April 2, 2010

Black silicon bringing down the cost of efficient solar

Filed under: Science — Tags: , , , , — David Kirkpatrick @ 7:03 pm

The latest news in one of the two areas — cost in this case — solar needs to continue to see improvement for widespread use.

From the link:

A simple chemical treatment could replace expensive antireflective solar cell coatings, bringing down the cost of crystalline silicon panels. The treatment, a one-step dip in a chemical bath, creates a highly antireflective layer of black silicon on the surface of silicon wafers, and it would cost just pennies per watt, say researchers at the National Renewable Energy Laboratory (NREL). They’ve used it to create black silicon solar cells that match the efficiency of conventional silicon cells on the market.

Solar goes black: These two solar cells were fabricated on a silicon wafer treated to create an antireflective black silicon surface. The silvery areas around the cells are a different color because the highly absorbent black layer has been etched away.
Credit: Hao-Chih Yuan

March 24, 2010

GE getting into thin-film solar field

This can only mean advances in production and manufacturing coupled with a likely cost reduction. A win for the field since GE is going to bring to bear its corporate might on process improvements.

From the link:

GE has confirmed long-standing speculation that it plans to make thin-film solar panels that use a cadmium- and tellurium-based semiconductor to capture light and convert it into electricity. The GE move could put pressure on the only major cadmium-telluride solar-panel maker, Tempe, AZ-based First Solar, which could drive down prices for solar panels.

Last year, GE seemed to be getting out of the solar industry as it sold off crystalline-silicon solar-panel factories it had acquired in 2004. The company found that the market for such solar panels–which account for most of the solar panels sold worldwide–was too competitive for a relative newcomer, says Danielle Merfeld, GE’s solar technology platform leader.

March 18, 2010

Beautiful space image — dust in the solar neighborhood

Very nice. And yes, I’ve been posting more space and nanotech images than usual of late.

The image spans about 50° of the sky. It is a three-colour combination constructed from Planck’s two highest frequency channels (557 and 857 GHz, corresponding to wavelengths of 540 and 350 micrometres), and an image at the shorter wavelength of 100 micrometres made by the IRAS satellite. This combination visualises dust temperature very effectively: red corresponds to temperatures as cold as 10° above absolute zero, and white to those of a few tens of degrees. Overall, the image shows local dust structures within 500 light-years of the Sun.

Credits: ESA/HFI Consortium/IRAS

Hit the link up there for the full release on this image

March 16, 2010

Increasing plastic solar cell efficiency

Even though I think it’s going to be the thin-film photovoltaic space is where we will see the most market ready advances in cost and efficiency, breakthroughs in other areas, like polymer solar cells, keep the entire field moving forward and might well lead to the next big thing down the road. It truly is promising to follow and read about the sheer volume of basic research and incremental improvements going on in solar and other alternative energy sources. The faster the United States can end dependency on Middle East petroleum, the faster one of the more vexing national security issues gets solved.

From the second link:

Polymer solar cells are finding use in solar charging backpacks and umbrellas, but they still only convert around 6 percent of the energy in sunlight into electricity–or around a third of what conventional silicon panels are capable of. If the efficiency of polymer solar cells–which are cheaper and lighter than silicon cells–can be boosted significantly, they could be ideal for plastering on rooftops or laminating on windows.

Solarmer Energy, based in El Monte, CA, is on target to reach 10 percent efficiency by the end of this year, says Yue Wu, the company’s managing director and director of research and development. Organic cells will likely need at least that efficiency to compete on the photovoltaic market.

Hit the first link above in the very first sentence of this post for a story on U.S. firms seeking to push the cost of thin-film solar cells down.

March 13, 2010

Dwarf star has 86% chance of crashing our solar system

Filed under: Science — Tags: , , , , — David Kirkpatrick @ 12:33 pm

But we have a little time to make arrangements. The collision is expected in the next 1.5 million years.

From the link:

A new set of star velocity data indicates that Gliese 710 has an 86 percent chance of ploughing into the Solar System within the next 1.5 million years.

And:

Today, Vadim Bobylev at the Pulkovo Astronomical Observatory in St Petersburg gives us the answer. He’s combined the Hipparcos data with several new databases and found an additional nine stars that have either had a close encounter with the Sun or are going to.

But he’s also made a spectacular prediction. The original Hipparcos data showed that an orange dwarf star called Gliese 710 is heading our way and will arrive sometime within the next 1.5 million years.

Of course, trajectories are difficult to calculate when the data is poor so nobody has really been sure about what’s going to happen.

What the new data has allowed Bobylev to do is calculate the probability of Gliese 710 smashing into the Solar System. What he’s found is a shock.

He says there is 86 percent chance that Gliese 710 will plough through the Oort Cloud of frozen stuff that extends some 0.5 parsecs into space.

That may sound like a graze but it is likely to have serious consequences. Such an approach would send an almighty shower of comets into the Solar System which will force us to keep our heads down for a while. And a probability of 86 percent is about as close to certainty as this kind of data can get.

March 5, 2010

Silicon nanowires may improve solar costs

Silicon photovoltaics offer incredible solar cell efficiency and now it looks like nanotechnology may offer a way to add low production cost to that mix. This type of headway and improvement is what will make solar a market-viable power option.

The release:

Trapping Sunlight with Silicon Nanowires

MARCH 03, 2010

Lynn Yarris

This photovoltaic cell is comprised of 36 individual arrays of silicon nanowires featuring radial p-n junctions. The color dispersion demonstrates the excellent periodicity present over the entire substrate. (Photo courtesy of Peidong Yang)

This photovoltaic cell is comprised of 36 individual arrays of silicon nanowires featuring radial p-n junctions. The color dispersion demonstrates the excellent periodicity over the entire substrate. (Photo from Peidong Yang)

Solar cells made from silicon are projected to be a prominent factor in future renewable green energy equations, but so far the promise has far exceeded the reality. While there are now silicon photovoltaics that can convert sunlight into electricity at impressive 20 percent efficiencies, the cost of this solar power is prohibitive for large-scale use. Researchers with the Lawrence Berkeley National Laboratory (Berkeley Lab), however, are developing a new approach that could substantially reduce these costs. The key to their success is a better way of trapping sunlight.

“Through the fabrication of thin films from ordered arrays of vertical silicon nanowires we’ve been able to increase the light-trapping in our solar cells by a factor of 73,” says chemist Peidong Yang, who led this research. “Since the fabrication technique behind this extraordinary light-trapping enhancement is a relatively simple and scalable aqueous chemistry process, we believe our approach represents an economically viable path toward high-efficiency, low-cost thin-film solar cells.”

Yang holds joint appointments with Berkeley Lab’s Materials Sciences Division, and the University of California  Berkeley’s Chemistry Department. He is a leading authority on semiconductor nanowires – one-dimensional strips of materials whose width measures only one-thousandth that of a human hair but whose length may stretch several microns.

“Typical solar cells are made from very expensive ultrapure single crystal silicon wafers that require about 100 micrometers of thickness to absorb most of the solar light, whereas our radial geometry enables us to effectively trap light with nanowire arrays fabricated from silicon films that are only about eight micrometers thick,” he says. “Furthermore, our approach should in principle allow us to use metallurgical grade or “dirty” silicon rather than the ultrapure silicon crystals now required, which should cut costs even further.”

Yang has described this research in a paper published in the journal NANO Letters, which he co-authored with Erik Garnett, a chemist who was then a member of Yang’s research group. The paper is titled “Light Trapping in Silicon Nanowire Solar Cells.”

A radial p-n junction consists of a layer of n-type silicon forming a shell around a p-type silicon nanowire core. This geometry turns each individual nanowire into a photovoltaic cell.

A radial p-n junction consists of a layer of n-type silicon forming a shell around a p-type silicon nanowire core. This geometry turns each individual nanowire into a photovoltaic cell.

Generating Electricity from Sunlight

At the heart of all solar cells are two separate layers of material, one with an abundance of electrons that functions as a negative pole, and one with an abundance of electron holes (positively-charged energy spaces) that functions as a positive pole. When photons from the sun are absorbed, their energy is used to create electron-hole pairs, which are then separated at the interface between the two layers and collected as electricity.

Because of its superior photo-electronic properties, silicon remains the photovoltaic semiconductor of choice but rising demand has inflated the price of the raw material. Furthermore, because of the high-level of crystal purification required, even the fabrication of the simplest silicon-based solar cell is a complex, energy-intensive and costly process.

Yang and his group are able to reduce both the quantity and the quality requirements for silicon by using vertical arrays of nanostructured radial p-n junctions rather than conventional planar p-n junctions. In a radial p-n junction, a layer of n-type silicon forms a shell around a p-type silicon nanowire core. As a result, photo-excited electrons and holes travel much shorter distances to electrodes, eliminating a charge-carrier bottleneck that often arises in a typical silicon solar cell. The radial geometry array also, as photocurrent and optical transmission measurements by Yang and Garrett revealed, greatly improves light trapping.

“Since each individual nanowire in the array has a p-n junction, each acts as an individual solar cell,” Yang says. “By adjusting the length of the nanowires in our arrays, we can increase their light-trapping path length.”

While the conversion efficiency of these solar nanowires was only about five to six percent, Yang says this efficiency was achieved with little effort put into surface passivation, antireflection, and other efficiency-increasing modifications.

“With further improvements, most importantly in surface passivation, we think it is possible to push the efficiency to above 10 percent,” Yang says.

Combining a 10 percent or better conversion efficiency with the greatly reduced quantities of starting silicon material  and the ability to use metallurgical grade silicon, should make the use of silicon nanowires an attractive candidate for large-scale development.

As an added plus Yang says, “Our technique can be used in existing solar panel manufacturing processes.”

This research was funded by the National Science Foundation’s Center of Integrated Nanomechanical Systems.

Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research for DOE’s Office of Science and is managed by the University of California. Visit our website at http://www.lbl.gov.


Peidong Yang (Photo by Roy Kaltschmidt, Berkeley Lab Public Affairs)

Peidong Yang (Photo by Roy Kaltschmidt, Berkeley Lab Public Affairs)

Additional Information

For more about the research of Peidong Yang and his group, visit the Website at http://www.cchem.berkeley.edu/pdygrp/main.html

For more about the Center of Integrated Nanomechanical Systems (COINS) visit the Website at http://mint.physics.berkeley.edu/coins/

March 2, 2010

Google is serious about developing solar

Filed under: Business, Science, Technology — Tags: , , , , — David Kirkpatrick @ 4:35 pm

Very serious.  A solar thermal plant pumping out electricity at 5 cents/kWh (or less!?!) would be pretty amazing. This advance in efficiency is coming through a redesign of the mirrors with new material on both the reflective surface and the substrate.

From the link:

Google announced last year that they were working on new technology that would make solar thermal energy cheaper than coal.  Just a few months later, they have a prototype and expect a product to be ready in as little as a year.

And:

The prototype is being internally tested before more rigorous external testing, but two solar companies, BrightSource and eSolar, are already interested in the technology.  Google is a major investor in both companies and has said if the prototype works, the companies would use the technology.

February 24, 2010

DoE makes major solar investment

Technically it’s a loan guarantee rather than a true investment, but this Department of Energy move shows just how serious the Obama administration is concerning alternate energy sources. There are a lot of exciting developments in solar power right now and government money in this amount only helps grease the wheels of innovation and private-sector investment.

From the first link:

The U.S. Department of Energy has announced a $1.37 billion conditional loan guarantee for the Ivanhoe Solar Complex in the Mojave Desert. The project, managed by Brightsource Energy, will use mirrors to concentrate sunlight, creating high temperatures that can be used to generate electricity. The complex will include three power plants that together will produce about 400 megawatts of electricity.

Basically, the guarantees would cover the loans in the case of default. The money for the loans is expected to come from the Federal Financing Bank.

One of the biggest challenges that large solar developments face is getting financing, particularly because few such solar power plants have been built. The DOE guarantees help on this front.

February 19, 2010

Broadband Solar offers latest breakthrough

Seems like I’ve been doing a whole lot of solar blogging lately, and here’s the latest breakthrough courtesy of Broadband Solar. This sounds more like an incremental improvement that will possibly lead to commercially viable thin-film solar cells rather than a game-changer ready for market. Even if this announcement doesn’t make it immediately easier or cheaper to put a bank of thin-film cells on the roof of your house, it is one more step toward that goal

From the second link:

Inexpensive thin-film solar cells aren’t as efficient as conventional solar cells, but a new coating that incorporates nanoscale metallic particles could help close the gap. Broadband Solar, a startup spun out of Stanford University late last year, is developing coatings that increase the amount of light these solar cells absorb.

Based on computer models and initial experiments, an amorphous silicon cell could jump from converting about 8 percent of the energy in light into electricity to converting around 12 percent. That would make such cells competitive with the leading thin-film solar cells produced today, such as those made by First Solar, headquartered in Tempe, AZ, says Cyrus Wadia, codirector of the Cleantech to Market Program in the Haas School of Business at the University of California, Berkeley. Amorphous silicon has the advantage of being much more abundant than the materials used by First Solar. The coatings could also be applied to other types of thin-film solar cells, including First Solar’s, to increase their efficiency.

Solar antenna: The square at the center is an array of test solar cells being used to evaluate a coating that contains metallic nanoantennas tuned to the solar spectrum.
Credit: Brongersma lab, Stanford

February 17, 2010

Efficient thin-film solar through nanotech

Filed under: Business, Science — Tags: , , , , , — David Kirkpatrick @ 2:54 pm

A nanotechnology design improves the efficiency of thin-film solar cells. An important breakthrough in working to commercially viable solar power because thin-film cells are cheaper than photovoltaics, but efficiency has been an issue. The two key elements  in making solar energy widespread and a credible challenger to petroleum-based energy are lower costs (both in installation and maintenance) and higher efficiencies. Anything that works to combine those two elements is a step in the right direction.

I just love blog posts that combine nanotechnology and solar power.

From the link:

Thin-film solar cells are less expensive than traditional photovoltaics sliced from wafers, but they’re not as efficient at converting the energy in sunlight into electricity. Now a Newton, MA-based startup is developing a nanostructured design that overcomes one of the main constraints on the performance of thin-film solar cells. Solasta fabricates on arrays of nanopillars, rather than flat areas, boosting the efficiency of amorphous silicon solar cells to about 10 percent–still less than crystalline silicon panels, but more than the thin-film amorphous silicon panels on the market today. The company says that the design won’t require new equipment or materials and that it will license its technology to amorphous-silicon manufacturers at the end of this year.

Pillar power: This microscope image shows the layers of a solar cell built on a nanopillar substrate. The core of each pillar is coated first with metal, then amorphous silicon, and then a transparent conductive oxide.

Credit: Solasta

February 11, 2010

IBM comes up with solar breakthrough

Filed under: Business, Science — Tags: , , , , , — David Kirkpatrick @ 1:49 am

There’s been a lot of solar energy news to blog about lately. Nestled in this spate of announcements is a breakthrough at IBM — solar cells created from abundant materials, well a higher proportion of abundant elements, than previous cells. The practical result? Cheaper to produce cells that don’t lose anything in the efficiency department, and cost and efficiency are the two issues that will determine when solar power becomes a viable alternative energy source.

From the second link:

Researchers at IBM have increased the efficiency of a novel type of solar cell made largely from cheap and abundant materials by over 40 percent. According to an article published this week in the journal Advanced Materials, the new efficiency is 9.6 percent, up from the previous record of 6.7 percent for this type of solar cell, and near the level needed for commercial solar panels. The IBM solar cells also have the advantage of being made with an inexpensive ink-based process.

The new solar cells convert light into electricity using a semiconductor material made of copper, zinc, tin, and sulfur–all abundant elements–as well as the relatively rare element selenium (CZTS). Reaching near-commercial efficiency levels is a “breakthrough for this technology,” says Matthew Beard, a senior scientist at the National Renewable Energy Laboratory, who was not involved with the work.

Copper power: This prototype solar cell uses a copper-based material and has achieved record efficiencies for a cell of its kind.

Credit: IBM Research

Update — head below the fold for IBM’s release on the new solar cell. (more…)

February 9, 2010

A solar power game-changer?

I couldn’t say with certainty, but this sure seems like it could be. This is obviously not ready for prime time (three years from serious production), but it is on the short horizon and if the claims bear out this tech completely alters the solar energy playing field.

From the link:

A startup company hopes to bring down the cost of generating power with concentrated sunlight by using microscale solar cells that can utilize twice as much light as other panels, without the need for expensive optics or cooling systems. Panels made from the tiny cells, which the Durham, NC-based company Semprius developed using a novel microprinting technology, also offer significant savings on materials costs. In late January, the company announced a joint agreement with Siemens to develop demonstration systems based on its technology. Semprius plans to begin volume production of the modules in 2013.

Microcell: The solar cells made by Semprius are 600 micrometers on each side and can be combined with high-power optics. The cell itself (the black square at center) is mounted atop a ceramic base with electrical contacts on each side.

Credit: Semprius

February 8, 2010

U.S. solar market about to explode

As solar technology continues to improve and costs continue to go down, predicting solar power in the United States is on the edge of a major boom is an easy call to make. A few of the major barriers to more widespread solar installations – particularly the efficiency of the solar panels and the physical difficulty of getting the panels installed and operating — are not the impediment they were just a couple of years ago.

From the first link:

In a few years, the United States is likely to be the world’s largest market for solar power, eclipsing Germany, which has taken the lead as a result of strong government incentives in spite of the relative paucity of sunlight in that country. A number of factors could make growth possible in the United States–especially changes in legislation that give utilities incentives to create large solar farms.

Last year, the U.S. solar industry got off to a slow start, but sales rebounded in the second half of the year, largely because of a drop in the prices of solar panels of up to 40 percent, partly caused by an oversupply due to the recession. Revenues for many solar companies were likely flat, but the megawatts of solar installed in the United States overall grew by 25 to 40 percent last year, says Roger Efird, the chairman of the Solar Energy Industry Association and the managing director of Suntech America, a branch of Suntech Power, the largest maker of crystalline silicon solar panels in the world.

This year, Efird says, solar installations could double, reaching a gigawatt of capacity. “That’s a big number,” he says. “If you are in the solar business, you were talking watts 15 years ago, you were talking kilowatts 10 years ago, and you have trouble even talking megawatts today.”

January 21, 2010

Solar power at 70 cents per watt

Filed under: Business, Science — Tags: , , , , — David Kirkpatrick @ 5:35 pm

Via KurzweilAI.net — An impressive milestone in solar power efficiency.

Oerlikon Promises 30% Lower Solar Module Production Costs in 2010
Renewable Energy World, Jan. 20, 2009

Oerlikon Solar plans to reach production costs at grid parity by the end of this year, meaning the company is on track to offer its customers an advanced fab design capable of producing solar modules for 70 cents per watt by that time.

Oerlikon Solar said that it has driven down module costs by around 25 percent, raising efficiency and improving the productivity of its lines from 60 MW in 2008 to 100 MW in 2009 without additional equipment.

The company also said that it is on track to deliver another 30% cost reduction by end of 2010, enabling customers to offer solar electricity at grid-competitive prices in many parts of the world.
Read Original Article>>

January 20, 2010

Solar shingles are about to become a market reality

Filed under: Business, Science — Tags: , , , , — David Kirkpatrick @ 2:14 am

Courtesy of Dow Chemical. Solar power has a lot of implementation issues, not the least of which is just getting solar panels installed. This looks like a big step in the right direction. These aren’t going to be cheap right off the bat, but they are going to remove a lot of installation issues from going solar on a building.

From the link:

Dow Chemical is moving full speed ahead to develop roof shingles embedded with photovoltaic cells. To facilitate the move, the U.S. Department of Energy has backed Dow’s efforts with a $17.8 million tax credit that will help the company launch an initial market test of the product later this year.

In October 2009, the chemical giant unveiled its product, which can be nailed to a roof like ordinary shingles by roofers without the help of specially trained solar installers or electricians. The solar shingles will cost 30 to 40 percent less than other solar-embedded building materials and 10 percent less than the combined costs of conventional roofing materials and rack-mounted solar panels, according to company officials.

Sunny future: Dow Chemical hopes to transform the solar power industry by integrating solar cells with conventional roofing shingles .

Credit: Dow Chemical

December 12, 2009

“Hot electrons” and solar cells

Filed under: Science — Tags: , , , , — David Kirkpatrick @ 4:29 pm

The latest solar breakthrough news.

The release:

Elusive ‘hot’ electrons captured in ultra-thin solar cells

Shrinking cells snares charges in less than one-trillionth of a second

CHESTNUT HILL, MA (12/11/2009) – Boston College researchers have observed the “hot electron” effect in a solar cell for the first time and successfully harvested the elusive charges using ultra-thin solar cells, opening a potential avenue to improved solar power efficiency, the authors report in the current online edition of Applied Physics Letters.

When light is captured in solar cells, it generates free electrons in a range of energy states. But in order to snare these charges, the electrons must reach the bottom of the conduction band. The problem has been that these highly energized “hot” electrons lose much of their energy to heat along the way.

Hot electrons have been observed in other devices, such as semiconductors. But their high kinetic energy can cause these electrons, also known as “hot carriers,” to degrade a device. Researchers have long theorized about the benefits of harnessing hot electrons for solar power through so-called “3rd generation” devices.

By using ultrathin solar cells – a film fewer than 30 nanometers thick – the team developed a mechanism able to extract hot electrons in the moments before they cool – effectively opening a new “escape hatch” through which they typically don’t travel, said co-author Michael J. Naughton, the Evelyn J. and Robert A. Ferris Professor of Physics at Boston College.

The team’s success centered on minimizing the environment within which the electrons are able to escape, said Professor of Physics Krzysztof Kempa, lead author of the paper.

Kempa compared the challenge to trying to heat a swimming pool with a pot of boiling water. Drop the pot into the center of the pool and there would be no change in temperature at the edge because the heat would dissipate en route. But drop the pot into a sink filled with cold water and the heat would likely raise the temperature in the smaller area.

“We have shrunk the size of the solar cell by making it thin,” Kempa said. “In doing so, we are bringing these hot electrons closer to the surface, so they can be collected more readily. These electrons have to be captured in less than a picosecond, which is less than one trillionth of a second.”

The ultrathin cells demonstrated overall power conversion efficiency of approximately 3 percent using absorbers one fiftieth as thick as conventional cells. The team attributed the gains to the capture of hot electrons and an accompanying reduction in voltage-sapping heat. The researchers acknowledged the film’s efficiency is limited by the negligible light collection of ultra-thin junctions. However, combining the film with better light-trapping technology – such as nanowire structures – could significantly increase efficiency in an ultra-thin hot electron solar cell technology.

###

In addition to Naughton and Kempa, the research team included Professor of Physics Zhifeng Ren, Research Associate Professor and Laboratory Director Andrzej A. Herczynski, Research Scientist Yantao Gao, doctoral student Timothy Kirkpatrick, and Jakub Rybczynski of Solasta Corp., of Newton MA, which supported the research. Naughton, Kempa and Ren are principals in the clean energy firm as well.

December 1, 2009

Dye-sensitized solar cell efficiency times three

Filed under: et.al. — Tags: , , , , — David Kirkpatrick @ 7:42 pm

Every step is one closer to cost-effective solar power.

The release:

Innovation puts next-generation solar cells on the horizon

In a world first, a Monash University-led international research team has developed an innovative way to boost the output of the next generation of solar cells.

Scientists at Monash University, in collaboration with colleagues from the universities of Wollongong and Ulm in Germany, have produced tandem dye-sensitised solar cells with a three-fold increase in energy conversion efficiency compared with previously reported tandem dye-sensitised solar cells.

Lead researcher Dr Udo Bach, from Monash University, said the breakthrough had the potential to increase the energy generation performance of the cells and make them a viable and competitive alternative to traditional silicon solar cells.

Dr Bach said the key was the discovery of a new, more efficient type of dye that made the operation of inverse dye-sensitised solar cells much more efficient.

When the research team combined two types of dye-sensitised solar cell – one inverse and the other classic – into a simple stack, they were able to produce for the first time a tandem solar cell that exceeded the efficiency of its individual components.

“The tandem approach – stacking many solar cells together – has been successfully used in conventional photovoltaic devices to maximise energy generation, but there have been obstacles in doing this with dye-sensitised cells because there has not been a method for creating an inverse system that would allow dye molecules to efficiently pass on positive charges to a semiconductor when illuminated with light,” Dr Bach said.

“Inverse dye-sensitised solar cells are the key to producing dye-sensitised tandem solar cells, but the challenge has been to find a way to make them perform more effectively. By creating a way of making inverse dye-sensitised solar cells operate very efficiently we have opened the way for dye-sensitised tandem solar cells to become a commercial reality.”

Although dye-sensitised solar cells have been the focus of research for a number of years because they can be fabricated with relative simplicity and cost-efficiency, their effectiveness has not been on par with high-performance silicon solar cells.

Dr Bach said the breakthrough, which is detailed in a paper published in Nature Materials, was an important milestone in the ongoing development of viable and efficient solar cell technology.

“While this new tandem technology is still in its early infancy, it represents an important first step towards the development of the next generation of solar cells that can be produced at low cost and with energy efficient production methods,” he said.

“With this innovation we are one step closer to the creation of a cost-efficient and carbon-neutral energy source.”

###

November 25, 2009

Self-assembling spherical solar cells

Via KurzweilAI.net — Pretty interesting solar concept. There is still a lot of innovation going on in the solar space.

Origami Solar Cells
Technology Review, Nov. 25, 2009

Researchers at the University of Illinois have developed self-assembling spherical solar cells capable of capturing more sunlight than flat ones.

If they prove practical, the devices could be wired up into large arrays that have the same power output as conventional cells, but that save on materials costs by using less silicon.


(PNAS)

 

Read Original Article>>

November 19, 2009

Cheap, efficient solar cells

Filed under: Business, Science, Technology — Tags: , , , , — David Kirkpatrick @ 1:47 pm

Via KurzweilAI.net — This sounds like good news. I’m looking forward to lower cost solar options to hit the market. There’s a lot of news in the space, but not much has translated to the real world. The general public will eventually tire of hearing about the latest and greatest solar ” breakthrough” (and I know I’m as guilty as anyone on that front) without seeing anything tangible. People can only be told the turn at the corner is coming soon so many times.

Thin-Film Solar with High Efficiency
Technology Review, Nov. 19, 2009

Solar cells made from cheap nanocrystal-based inks have the potential to be as efficient as the conventional inorganic cells currently used in solar panels, but can be printed less expensively, says Solexant, which expects to sell modules for $1 per watt, with efficiencies above 10 percent.

 

Read Original Article>>

November 16, 2009

Beautiful nanotech image — photovoltaic solar cell

This is a nice gallery of nanotech images from New Scientist. Here’s the description from the series, “Chemist George Whitesides has collaborated with MIT and Harvard photographer-in-residence Felice Frankel to produce No Small Matter, a book of images of the micro and nanoworld.”

From the first image, my favorite:

Sun catchers

This is a close-up of the top side of a photovoltaic solar cell. The cell converts the energy from the sun’s photons into electrical energy by taking advantage of the photo-electric effect. This cell is made of a wafer of crystalline silicon.

Light is absorbed by the wafer and creates charge that is collected by silver conductor lines, shown in the image as the gold-coloured strip. The cell is coated with silicon nitride which acts as an anti-reflective surface, preventing light energy from bouncing away and giving the cell its blue-violet colour.

Rather than attaching solar panels to our roofs, recent research suggests that in the future we could paint solar cells on to our houses, removing the need to rely on expensive silicon wafers.

(Image: Felice Frankel)

November 10, 2009

Japan planning space-based solar power plant

Via KurzweilAI.net — Space-based solar collection gets a lot of ink and now it looks like it might even get a test run.

apan eyes solar station in space as new energy source
AFP, Nov. 8, 2009

The Japan Aerospace Exploration Agency (JAXA) plans to collect solar power in space and send it to Earth by 2030 using laser beams or microwaves, and has created a consortium (the Institute for Unmanned SpaceExperiment Free Flyer) that includes Mitsubishi Heavy Industries, Mitsubishi Electric, NEC, Fujitsu and Sharp.


(Japan Institute for Unmanned Space Experiment Free Flyer)

 

Read Original Article>>

November 5, 2009

Solar energy and the artificial leaf

Very interesting solar breakthrough, or near to it at least. Plus more on the state of the solar industry.

The release:

Chemists describe solar energy progress and challenges, including the ‘artificial leaf’

WASHINGTON, Nov. 5, 2009 — Scientists are making progress toward development of an “artificial leaf” that mimics a real leaf’s chemical magic with photosynthesis — but instead converts sunlight and water into a liquid fuel such as methanol for cars and trucks. That is among the conclusions in a newly-available report from top authorities on solar energy who met at the 1st Annual Chemical Sciences and Society Symposium. The gathering launched a new effort to initiate international cooperation and innovative thinking on the global energy challenge.

The three-day symposium, which took place in Germany this past summer, included 30 chemists from China, Germany, Japan, the United Kingdom and the United States. It was organized through a joint effort of the science and technology funding agencies and chemical societies of each country, including the U. S. National Science Foundation and the American Chemical Society (ACS), the world’s largest scientific society. The symposium series was initiated though the ACS Committee on International Activities in order to offer a unique forum whereby global challenges could be tackled in an open, discussion-based setting, fostering innovative solutions to some of the world’s most daunting challenges.

A “white paper” entitled “Powering the World with Sunlight,” describes highlights of the symposium and is available along with related materials here.

“The sun provides more energy to the Earth in an hour than the world consumes in a year,” the report states. “Compare that single hour to the one million years required for the Earth to accumulate the same amount of energy in the form of fossil fuels. Fossil fuels are not a sustainable resource, and we must break our dependence on them. Solar power is among the most promising alternatives.”

The symposium focused on four main topics:

  • Mimicking photosynthesis using synthetic materials such as the “artificial leaf”
  • Production and use of biofuels as a form of stored solar energy
  • Developing innovative, more efficient solar cells
  • Storage and distribution of solar energy

     

The scientists pointed out during the meeting that plants use solar energy when they capture and convert sunlight into chemical fuel through photosynthesis. The process involves the conversion of water and carbon dioxide into sugars as well as oxygen and hydrogen. Scientists have been successful in mimicking this fuel-making process, termed artificial photosynthesis, but now must finds ways of doing so in ways that can be used commercially. Participants described progress toward this goal and the scientific challenges that must be met before solar can be a viable alternative to fossil fuels.

Highlights of the symposium include a talk by Kazunari Domen, Ph.D., of the University of Tokyo in Japan. Domen described current research on developing more efficient and affordable catalysts for producing hydrogen using a new water-splitting technology called “photocatalytic overall water splitting.” The technology uses light-activated nanoparticles, each 1/50,000 the width of a human hair, to convert water to hydrogen. This technique is more efficient and less expensive than current technologies, he said.

Domen noted that the ultimate goal of artificial photosynthesis is to produce a liquid fuel, such as methanol, or “wood alcohol.” Achieving this goal would fulfil the vision of creating an “artificial leaf” that not only splits water but uses the reaction products to create a more usable fuel, similar to what leaves do.

Among the “take-home messages” cited in the report:

  • There’s no single best solution to the energy problem. Scientists must seek more affordable, sustainable solutions to the global energy challenge by considering all the options.
  • Investing in chemistry is investing in the future. Strong basic research is fundamental to realizing the potential of solar energy and making it affordable for large-scale use.
  • Society needs a new generation of “energy scientists” to explore new ways to capture, convert, and store solar energy.

     

“The meeting was an experiment worth trying,” said Teruto Ohta, executive director of the Chemical Society of Japan.

Conference organizers expressed hope that the symposium will be the first of several to tackle “the global challenges of the 21st century and the indispensible role that the chemical sciences play in addressing these issues,” said Klaus Mullen, president of the German Chemistry Association.

“Building on the success of this first symposium, we’re now gearing up for the future, convening top chemical scientists to address other, equally pressing global challenges,” said Julie Callahan of the ACS Office of International Activities and principal investigator on the project. “It is an exciting time to be a chemist!”

###

The American Chemical Society is a nonprofit organization chartered by the U.S. Congress. With more than 154,000 members, ACS is the world’s largest scientific society and a global leader in providing access to chemistry-related research through its multiple databases, peer-reviewed journals and scientific conferences. Its main offices are in Washington, D.C., and Columbus, Ohio.

China dominating solar manufacturing

If you follow the solar cell industry at all that fact should be very readily apparent. The Chinese government has put great emphasis o0n and money into solar. One major advantage Chinese firms have over U.S. and European competitors that’s not going away any time soon is labor costs.

From the link:

Solar companies presenting business plans to investors at a National Renewable Energy Laboratory (NREL) conference this week devoted particular attention to how they hope to compete with Chinese manufacturers. The audience at the NREL Industry Growth Forum in Denver consisted largely of venture capitalists and partners from private equity firms.

Stellaris, a company that assembles solar modules in Lowell, MA, has already received $6.1 million in funding to develop techniques for packaging silicon and thin-film cells. The company, represented at the conference by CEO James Paull, is seeking further financing in 2010.

October 30, 2009

Improving dye-sensitized solar cells

Efficiencies are going up and costs and holding steady or falling. All this bodes well for the future of solar power.

From the link:

Dye-sensitized solar cells are flexible and cheap to make, but they tend to be inefficient at converting light into electricity. One way to boost the performance of any solar cell is to increase the surface area available to incoming light. So a group of researchers at Georgia Tech has made dye-sensitized solar cells with a much higher effective surface area by wrapping the cells around optical fibers. These fiber solar cells are six times more efficient than a zinc oxide solar cell with the same surface area, and if they can be built using cheap polymer fibers, they shouldn’t be significantly more expensive to make.

The advantage of a fiber-optic solar-cell system over a planar one is that light bounces around inside an optical fiber as it travels along its length, providing more opportunities to interact with the solar cell on its inner surface and producing more current. “For a given real estate, the total area of the cell is higher, and increased surface area means improved light harvesting and more energy,” says Max Shtein, an assistant professor of materials science and engineering at the University of Michigan who was not involved with the research.

Solar on fiber: An optical fiber (left) is covered in dye-coated zinc-oxide nanowires (closeup, right). Both images were made using a scanning electron microscope.
Credit: Angewandte Chemie

October 22, 2009

Solar costs are dropping

Interesting news from the Lawrence Berkeley National Laboratory.

The release:

Installed cost of solar photovoltaic systems in the US fell in 2008

Researchers at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) released a new study on the installed costs of solar photovoltaic (PV) power systems in the U.S., showing that the average cost of these systems declined by more than 30 percent from 1998 to 2008. Within the last year of this period, costs fell by more than 4 percent.

The number of solar PV systems in the U.S. has been growing at a rapid rate in recent years, as governments at the national, state, and local levels have offered various incentives to expand the solar market. With this growth comes a greater need to track and understand trends in the installed cost of PV.

“A goal of government incentive programs is to help drive the cost of PV systems lower. One purpose of this study is to provide reliable information about the costs of installed systems over time,” says report co-author Ryan Wiser.

According to the report, the most recent decline in costs is primarily the result of a decrease in PV module costs. “The reduction in installed costs from 2007 to 2008 marks an important departure from the trend of the preceding three years, during which costs remained flat as rapidly expanding U.S. and global PV markets put upward pressure on both module prices and non-module costs. This dynamic began to shift in 2008, as expanded manufacturing capacity in the solar industry, in combination with the global financial crisis, led to a decline in wholesale module prices,” states the report, which was written by Wiser, Galen Barbose, Carla Peterman, and Naim Darghouth of Berkeley Lab’s Environmental Energy Technologies Division.

In contrast, cost reductions from 1998 through 2007 were largely due to a decline in non-module costs, such as the cost of labor, marketing, overhead, inverters, and the balance of systems.

The study—the second in an ongoing series that tracks the installed cost of PV—examined 52,000 grid-connected PV systems installed between 1998 and 2008 in 16 states. It found that average installed costs, in terms of real 2008 dollars, declined from $10.80 per watt (W) in 1998 to $7.50/W in 2008, equivalent to an average annual reduction of $0.30/W, or 3.6 percent per year in real dollars.

Costs Differ by Region and Type of System

Other information about differences in costs by region and by installation type emerged from the study. The cost reduction over time was largest for smaller PV systems, such as those used to power individual households. Also, installed costs show significant economies of scale—small residential PV systems completed in 2008 that were less than 2 kilowatts (kW) in size averaged $9.20/W, while large commercial systems in the range of 500 to 750 kW averaged $6.50/W.

Installed costs were also found to vary widely across states. Among systems completed in 2008 and less than 10 kW in size, average costs range from a low of $7.30/W in Arizona, followed by California, which had average installed costs of $8.20/W, to a high of $9.90/W in Pennsylvania and Ohio. Based on these data, and on installed cost data from the sizable German and Japanese PV markets, the authors suggest that PV costs can be driven lower through large-scale deployment programs.

The study also found that the new construction market offers cost advantages for residential PV systems. Among small residential PV systems in California completed in 2008, those systems installed in residential new construction cost $0.80/W less than comparably-sized systems installed in rooftop retrofit applications.

Cash Incentives Declined

The study also found that the average size of direct cash incentives provided by state and local PV incentive programs declined over the 1998-2008 study period. Other sources of incentives, however, such as federal investment tax credits (ITCs), have become more significant. For commercial PV systems, the average combined after-tax value of federal and state ITCs, plus direct cash incentives provided by state and local incentive programs, was $4.00/W in 2008, down slightly from its peak in 2006 but still a near-record-high. Total after-tax incentives for residential systems, on the other hand, were at an historic low in 2008, averaging $2.90/W, their lowest level within the 11-year study period.

The drop in total after-tax incentives for both commercial and residential PV from 2007 to 2008 more than offset the cost reduction over this period, leading to a slight rise in the net installed cost, or the installed cost facing a customer after receipt of financial incentives. For residential PV, net installed costs in 2008 averaged $5.40/W, up 1% from the previous year. Net installed costs for commercial PV averaged $4.20/W, a 5% rise from 2007.

###

The report “Tracking the Sun II: The Installed Cost of Photovoltaics in the U.S. from 1998�,” by Ryan Wiser, Galen Barbose, Carla Peterman, and Naim Darghouth may be downloaded from http://eetd.lbl.gov/ea/emp/re-pubs.html. The research was supported by funding from the U.S. Department of Energy’s Office of Energy Efficiency and Renewable Energy (Solar Energy Technologies Program) and by the Clean Energy States Alliance.

Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research and is managed by the University of California. Visit our website at http://www.lbl.gov.

October 18, 2009

IBEX finds solar system surprise

This release is from Friday and I’ve read this news a few different places and caught several releases, but this one is pretty comprehensive and contains a multitude of citations and external links.

Surprises in any scientific research are interesting, and often they are pretty cool.

The release:

Satellite reveals surprising cosmic ‘weather’ at edge of solar system

IMAGE: Priscilla Frisch, Senior Scientist in Astronomy & Astrophysics, and member of the science team, Interstellar Boundary Explorer. Collaborating with former UChicago astronomer Thomas F. Adams, she made the first spectrum…

Click here for more information.

The first solar system energetic particle maps show an unexpected landmark occurring at the outer edge of the solar wind bubble surrounding the solar system. Scientists published these maps, based mostly on data collected from NASA’s Interstellar Boundary Explorer satellite, in the Oct. 15 issue of Science Express, the advance online version of the journal Science.

“Nature is full of surprises, and IBEX has been lucky to discover one of those surprises,” said Priscilla Frisch, a senior scientist in astronomy & astrophysics at the University of Chicago. “The sky maps are dominated by a giant ribbon of energetic neutral atoms extending throughout the sky in an arc that is 300 degrees long.” Energetic neutral atoms form when hot solar wind ions (charged particles) steal electrons from cool interstellar neutral atoms.

IBEX was launched Oct. 19, 2008, to produce the first all-sky maps of the heliosphere, which reaches far beyond the solar system’s most distant planets. Extending more than 100 times farther than the distance from Earth to the sun, the heliosphere marks the region of outer space subjected to the sun’s particle emissions.

The new maps show how high-speed cosmic particle streams collide and mix at the edge of the heliosphere, said Frisch, who co-authored three of a set of IBEX articles appearing in this week’s Science Express. The outgoing solar wind blows at 900,000 miles an hour, crashing into a 60,000-mile-an-hour “breeze” of incoming interstellar gas.

Revealed in the IBEX data, but not predicted in the theoretical heliosphere simulations of three different research groups, was the ribbon itself, formed where the direction of the interstellar magnetic field draping over the heliosphere is perpendicular to the viewpoint of the sun.

IMAGE: Image from one of the IBEX papers published in the Oct. 16, 2009, issue of Science showing a map of the ribbon of energetic neutral atoms (in green and yellow)…

Click here for more information.

Energetic protons create forces as they move through the magnetic field, and when the protons are bathed in interstellar neutrals, they produce energetic neutral atoms. “We’re still trying to understand this unexpected structure, and we believe that the interstellar magnetic forces are associated with the enhanced ENA production at the ribbon,” Frisch said.

IBEX shows that energetic neutral atoms are produced toward the north pole of the ecliptic (the plane traced by the orbit of the planets around the sun), as well as toward the heliosphere tail pointed toward the constellations of Taurus and Orion. “The particle energies change between the poles and tail, but surprisingly not in the ribbon compared to adjacent locations,” Frisch said.

###

BEX is the latest in NASA’s series of low-cost, rapidly developed Small Explorers space missions. Southwest Research Institute in San Antonio, Texas, leads and developed the mission with a team of national and international partners. NASA’s Goddard Space Flight Center in Greenbelt, Md., manages the Explorers Program for NASA’s Science Mission Directorate in Washington.

Citations: N. A. Schwadron, M. Bzowski, G. B. Crew, M. Gruntman, H. Fahr, H. Fichtner, P. C. Frisch, H. O. Funsten, S. Fuselier, J. Heerikhuisen, V. Izmodenov, H. Kucharek, M. Lee, G. Livadiotis, D. J. McComas, E. Moebius, T. Moore, J. Mukherjee, N.V. Pogorelov, C. Prested, D. Reisenfeld, E. Roelof, G.P. Zank, “Comparison of Interstellar Boundary Explorer Observations with 3-D Global Heliospheric Models,” ScienceExpress, Oct. 15, 2009.

H.O. Funsten, F. Allegrini, G.B. Crew, R. DeMajistre, P.C. Frisch, S.A. Fuselier, M. Gruntman, P. Janzen, D.J. McComas, E. Möbius, B. Randol, D.B. Reisenfeld, E.C. Roelof, N.A. Schwadron, “Structures and Spectral Variations of the Outer Heliosphere in IBEX Energetic Neutral Atom Maps,”Science Express, Oct. 15, 2009.

D.J. McComas, F. Allegrini1, P. Bochsler, M. Bzowski, E.R. Christian, G.B.Crew, R. DeMajistre, H. Fahr, H. Fichtner, P.C. Frisch, H.O. Funsten, S. A. Fuselier, G. Gloeckler, M. Gruntman, J. Heerikhuisen, V. Izmodenov, P.J anzen, P. Knappenberger, S. Krimigis, H. Kucharek, M. Lee, G. Livadiotis, S. Livi, R.J. MacDowall, D. Mitchell, E. Möbius, T. Moore, N.V. Pogorelov, D. Reisenfeld, E. Roelof, L. Saul, N.A. Schwadron, P.W. Valek, R. Vanderspek, P. Wurz, G.P. Zank, “Global Observations of the Interstellar Interaction from the Interstellar Boundary Explorer-IBEX”, ScienceExpress, Oct. 15, 2009.

Related links:

Animation shows how energetic neutral atoms are made in the heliosheath when hot solar wind protons grab an electron from a cold interstellar gas atom. The ENAs can then easily travel back into the solar system, where some are collected by IBEX. Credit: NASA/GSFChttp://www.swri.org/temp/ibexscience/DM/SP_draft1.mov

Solar Journey: The Significant of Our Galactic Environment for the Heliosphere and Earth, Priscilla C. Frisch, editor.http://www.springer.com/astronomy/practical+astronomy/book/978-1-4020-4397-0

IBEX Web page at Southwest Research Institute http://ibex.swri.edu/

NASA’s Interstellar Boundary Explorer mission http://www.nasa.gov/mission_pages/ibex/index.html

To view a video related to this research, please visit http://astro.uchicago.edu/%7Efrisch/soljourn/Hanson/AstroBioScene7Sound.mov

If you’re dying for more on the topic, here’s another press release.

September 21, 2009

Silicon ink solar cells

Filed under: Business, Science, Technology — Tags: , , , — David Kirkpatrick @ 3:41 pm

Created with via inkjet and fairly efficient. Looks like all the solar innovations announced over the last few years are beginning to bear real-world fruit.

From the link:

A California company is using silicon ink patterned on top of silicon wafers to boost the efficiency of solar cells. The Sunnyvale, CA, firm Innovalight says that the inkjet process is a cheaper route to more-efficient solar power. Using this process, the company has made cells with an efficiency of 18 percent.

Inkjet solar: The inkjet printing process allows Innovalight to make silicon wafers that are thin enough to bend.
Credit: Innovalight

Innovalight has partnered with solar-cell manufacturerJA Solar, headquartered in Shanghai, which plans to integrate the inkjet printing technology into its manufacturing lines. The resulting solar cells should be on the market by next year.

It’s possible to increase the efficiency of solar cells by patterning silicon in a way that improves the absorption of high-energy, short-wavelength light. But this usually requires adding several etching steps to the manufacturing process, and this type of cell architecture “costs a lot of money to make using standard procedures,” says Homer Antoniadis, chief technology officer at Innovalight.

September 18, 2009

New equation for extrasolar life

Filed under: Science — Tags: , , , — David Kirkpatrick @ 5:18 pm

Via KurzweilAI.net — An updated Drake equation. Ah, aliens …

New ‘Drake equation’ for alien habitats

Cosmos, Sept. 17, 2009

A new equation under development by planetary scientists at the Open University in Milton Keynes, England aims to develop a single index for habitability elsewhere in our galaxy based on the presence of energy, solvents such as water, raw materials like carbon and whether or not there are benign environmental conditions.

Read Original Article>>

September 17, 2009

Nanosolar’s panels heading to the marketplace

Filed under: Business, Science, Technology — Tags: , , , , — David Kirkpatrick @ 6:36 pm

(Note this is the replacement for this lost post without some of the additional commentary on the feasibility of alternative power.)

Via KurzweilAI.net:

Advanced Solar Panels Coming to Market

Technology Review, Sept. 17, 2009

Nanosolar has opened an automated facility for manufacturing its solar panels, and says power plants made using these panels could produce electricity at five to six cents per kilowatt hour — near the cost of electricity from coal and significantly less than most solar power, which costs about 18 to 22 cents per kilowatt hour.

The panels are made by printing a semiconductor material called CIGS (copper, indium, gallium, and selenium) on aluminum foil.


Nanosolar’s new, fully automated solar-panel manufacturing facility (Nanosolar)

Read Original Article>>

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