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July 14, 2009 On a cost/Watt basis, thin-film solar PV is potentially very attractive, with CdTe leading the way today and tandem silicon cells and CIGS not far from catching up, notes Linx Consulting’s Mark Thirsk. And if the technical challenges with thin-film technology are solved, he’s bullish that it may take over a 30% share of the market.

Though he characterizes solar PV technology in general as “very mature,” Thirsk does see some areas bringing in technology improvements; e.g. diamond saws, which offer advantages in material reclaim. One showstopper, he suggests, could be what happens to production of virgin silicon if the industry slows down. But overall he sees the technology continuing to improve, driving better utilization of silicon.

Also, he notes there’s a “lot of thrust” in North America with thin-film technology, with CdTe and CIGS “upping the ante” to generate more power for much less material.

by Debra Vogler, senior technical editor, Solid State Technology

July 14, 2009 – XeroCoat Pty Ltd, a wholly owned subsidiary of XeroCoat Inc., has been awarded a grant from the Australian Government’s Climate Ready program to further develop its anti-soiling coating technology, which complements the company’s anti-reflective coating (ARC) for the cover glass of solar modules (see Figures 1 and 2). Together, these technologies will deliver more light to the solar module, increasing energy output.

“A module in the field collects debris, dirt, soils, etc., and these act to slightly shade the underlying converting elements,” company CEO, Michael Harvey, told PV World. “One solution is to keep the modules clean, but it’s not economically viable to continuously clean modules.”

The anti-soiling technology — which is presently at the research stage, Harvey pointed out — is expected to work in either of two ways. The first approach is to prevent soil from sticking to the module in the first place. One could do this by, say, using wind and gravity as the “cleaning process,” allowing soil to slide off more easily, and preventing it from adhering to the surface. The second approach is to accept that to some extent the soil will be there, so make it easier to remove by natural processes (e.g., morning dew occurs even in a desert environment, as do small amounts of rain). “The actual solution may be a combination of these two — we don’t yet know,” noted Harvey.


Figure 1. AFM photo of the surface of a XeroCoat ARC. (Source: XeroCoat)
CLICK HERE to view larger image

The company started working on the anti-soiling program last year (its research group is in Brisbane, Australia), with assistance from the Climate Ready Grant from the Australian government. XeroCoat’s plan is to have candidate materials ready for testing and evaluation by select customers in early 2010, “and then moving to scale up, having a product offering by late 2010,” Harvey told PV World.

The need to keep the module’s surface clean is well understood, noted Harvey, and solar farms have a cleaning cycle they go through, “so in addition to the extra energy, if we can reduce the frequency of the cleaning cycle, there’s an additional operational savings there as well.”

Energy savings by combining ARC with anti-soiling technology are seen as significant. Solar modules lose energy output because of reflections and the accumulation of dust and dirt on their surface. The loss due to reflections is 4% at noon and increases to over 15% in morning and early evening hours. In dry regions, the losses due to the build-up of dirt and dust can be 4%-6% of the total energy output.


Figure 2. SEM cross-section photo of a XeroCoat ARC. (Source: XeroCoat)

XeroCoat was one of 19 companies to share in the AUD$16 million awarded in round two of the Climate Ready program; the funding for XeroCoat’s anti-soiling program, together with the Climate Ready grant, is close to AUD$2 million. The $75 million Climate Ready program, administered by AusIndustry, is part of the Australian Government’s Clean Business Australia initiative, a $240 million, four-year partnership between government and industry to deliver energy and water efficient projects with a focus on energy and innovation.

The Climate Ready Grant adds to the grants that XeroCoat has received from Australian and Queensland government institutions. XeroCoat’s Project, Anti-reflective Coatings for Solar Collectors, was awarded a grant in 2006 from the Queensland Sustainable Energy Innovation Fund (QSEIF). XeroCoat was a previous recipient of an Innovation Start-up Scheme (ISUS) Grant from the Queensland government in 2005 and a Commercial Ready Grant from AusIndustry in 2007. — D.V.

by Debra Vogler, senior technical editor, Photovoltaics World

July 8, 2009 – Mallinckrodt Baker announced two new solar cell surface modifier products, the PV-162 and PV-200, that will enhance solar cell efficiency by up to 0.7% absolute, increasing cell energy output for both inline and batch solar cell manufacturing processes.

The new processes enable efficiency enhancing benefits of post-emitter surface modification for both in line and batch c-Si solar cell manufacturing, according to John Harris, global marketing manager, photovoltaics materials, at Mallinckrodt Baker. “Previously, our PV-160 product was applicable only to inline processing,” he told PV World, “but these two new products have opened up another part of the c-Si market — batch processing, a large segment of the market that we couldn’t address before (Figure 1).”


Figure 1. Schematic overview of the solar cell manufacturing process. (Source: Mallinckrodt Baker)
CLICK HERE to view larger image

The products work to increase cell efficiency by reducing the amount of recombination sites at or near the surface of the emitter. “By doing this, we are either (depending on the solar cell product) increasing the fill factor, increasing the open circuit voltage, or increasing the short circuit current or some combination of these three,” explained Harris. He noted that the PV-162 increases all three attributes; the PV-200 only increases the open circuit voltage and short circuit current.

PV-162 is a second-generation post-emitter surface modification product that remains compatible with current manufacturing equipment used with the PV-160 chemistry. It is a 100% water-soluble formulation requiring no intermediate rinse.

PV-200 solar cell surface modifier extends the efficiency enhancing benefits of post-emitter surface modification to batch processes that use phosphorus oxychloride (POCl3 or POCL) doping technology. Additionally, its tunable etch enables optimization of the manufacturing process. Its low bath temperature (20-40°C) reduces energy expenditures while providing extended bath life, reducing overall cost-of-ownership.

Figure 2 shows the removal of phosphosilicate glass (PSG) remnants by emitter optimization technology. “PSG is formed during the doping process when the wafers are fed through an in line furnace to drive phosphorus atoms into the crystal lattice,” Harris told PV World. “PSG has to be removed prior to the next step (ARC) and an HF bath is usually used to do this.” He noted that the SEM shows a simple HF dip that leaves PSG residue, which creates recombination sites in the emitter and lowers cell efficiency. “Our emitter optimization removes this residue and creates a more optimal emitter, reducing recombination sites in the emitter and improving cell efficiency.” — D.V.

This article was originally published by Photovoltaics World.


Figure 2. SEM micrographs showing the removal of PSG remnants by emitter optimization technology. Bar is 60μm (Source: Mallinckrodt Baker)

July 6, 2009 – Worldwide sales of semiconductors continue to creep up, and some comparisons are starting to look a little healthier — particularly compared with the end of 2008.

Global sales rose to $16.5B in May (a three-month average), a 5.4% climb from April, and down -23.2% from a year ago. That year-on-year comparison has started to slightly improve, as the year-ago period moves toward the beginning of the economic and industry quagmire. Looking at specific regions, all showed another slightly better month vs. a year ago, though all still well in the reds.

Looking at the three-month moving average offers a stronger piece of evidence that current data shows improvement on its own merits. Compared with the Dec/Jan/Feb period, chip sales in March/April/May spiked 16% — Asia-Pacific sales doubled to nearly 29%, sales growth in the Americas rose from 2% to 10%; Europe swung into the black (from -4.6% to 2.6%), and Japan went from a -20% hole to nearly flat (-1%).

How close to point-blank optimism are we? Not quite there, but getting close — enough that SIA president George Scalise sees a three-month trend of improving numbers as reason to be “cautiously optimistic about a return to normal seasonal patterns for the industry going forward.”

June 29, 2009: Carl Zeiss says it will debut before year’s end a new line of high-resolution microscopes combining its HR-SIM (high-resolution structured illumination) and PAL-M (photoactivated localization) technologies, targeting biomedical research.

In a press release, Zeiss explains the benefit of HR-SIM, developed with King’s College in London, is enlarging 3D spatial resolution by projecting a special illumination pattern onto a specimen, which permits multicolored visualization of structures with ~120nm lateral resolution. The PAL-M technique, licensed from the Howard Hughes Medical Institute, allows observation of cell structures with ~20nm resolution, an order of magnitude higher than conventional fluorescence techniques.

Ten of the new systems are now being tested at unidentified “internationally renowned” research labs, and “will be presented to the public at the end of the year.” One of those early adopters could be the National Institute of Health in Bethesda, MD (the Zeiss PR quotes two scientists, Catherine and James Galbraith, who appear to have ties there). “The integration of PAL-M and HR-SIM into a single platform has the unique advantage of localizing individual molecules and placing them in the context of images that have twice the resolution of conventional techniques,” stated James Galbraith. Added Catherine: “Being able to visualize and interpret the position of molecules at the nanometer scale is letting us ask questions that we never dreamed asking, let alone answering.”

June 26, 2009: Researchers at Brown U. say they have devised a way to eliminate bacteria that invade human tissue though medical devices: send magnetic nanoparticle “headhunters” after them.

Their findings, published in the International Journal of Nanomedicine, address the problem of Staphylococcus epidermidis, a bacteria commonly found on human skin and generally innocuous — unless it gets inside the body; it’s one of the leading causes of infections in hospitals. Among the various ways s. epidermis gets into the body is by “hitching a ride” on medical device implants, e.g. catheters, prostheses, etc. Once inside, the bacteria multiply on the device’s surface and generate a slimy film that wards off antibiotics — up to 2.5% of hip and knee implants in the US thus become infected.

To do battle, Brown researchers Thomas Webster and Erik Taylor focused on superparamagnetic iron-oxide nanoparticles (8nm-high, and chosen for magnetic maneuverability and trackability) to zero in on the implant. Once there the nanoparticles penetrate the bacterial shield (they speculate that a strong enough magnetic field forces them through); once inside the defenses the particles penetrate the bacterial cells and kill them in an as-yet unknown process. (Iron was known to kill s. epidermis, but Webster speculates it may be due to iron overload in the bacteria cell.) After 48hrs, 10μg of the agents were seen to eliminate up to 28% of the bacteria; in three treatments over six days, essentially all of them were destroyed, indicating “a continual killing of the bacteria until the film is gone,” noted Webster.

Next steps are to see how the iron-oxide nanoparticles fare against other bacteria, and then eventually move the research into trials with implants in animals. And they also want to better understand something else they saw as a result of the nanoparticle infusion — promotion of natural bone cell growth on the implant’s surface.

The research was funded by the private Hermann Foundation and in part by the National Science Foundation.


Iron-oxide nanoparticles developed at Brown University target an infected prosthesis, penetrate a bacterial film on the implant’s surface and thwart the colony by killing the bacteria. The nanoparticles also are believed to help natural bone cell growth. (Credit: Erik Taylor/Brown University)

June 26, 2009: Researchers in South Carolina are raising red flags about the potential impact of nanoparticles, by tracking how easily they can distribute through a marine ecosystem and up the food chain.

The paper, published this week by the journal Nature Nanotechnology, highlights work from scientists at the University of South Carolina’s Nanocenter and the National Oceanic and Atmospheric Administration’s Coastal Center for Environmental Health and Biomolecular Research (CCEHBR), who note that nanoparticles can move easily into the marine ecosystem, absorbed and transferred from marsh grasses to biofilms and into filter-feeding species such as clams.

The group introduced gold nanorods (selected for their traceability) into three lab replications of a coastal estuarine ecosystem, complete with a tidal marsh creek and sea water, sea grass in sediment, microbes, biofilms, snails, clams, shrimp, and fish. From the paper abstract:

A single dose of gold nanorods (65nm length × 15nm diameter) was added to each mesocosm and their distribution in the aqueous and sediment phases monitored over 12 days. Nanorods partitioned between biofilms, sediments, plants, animals and sea water with a recovery of 84.4%. Clams and biofilms accumulated the most nanoparticles on a per mass basis, suggesting that gold nanorods can readily pass from the water column to the marine food web.

The study’s main take-away appears to be that more work is needed to more specifically determine how nanoparticles are transported and distributed through a marine environment. “We did not look at what happens ‘up the food chain,” noted CCEHBR director Geoff Scott, in a statement discussing the study and its results. But this preliminary work suggests a clear need to understand the impact on nanoparticles on shellfish and fish which humans eat. One interesting observation along these lines: the clams “accumulated a significant amount of the nanomaterial,” Scott noted.

June 25, 2009: Arkansas Gov. Mike Beebe has released $1.5M from the state’s General Improvement Fund to the U. of Arkansas for construction of a new Nanotechnology Center.

“Governor Beebe has long been one of the strongest supporters of our nanotechnology research, and this is very concrete evidence of that support,” said Chancellor G. David Gearhart, in a statement from the school. “The governor has the vision to see this as an investment in our state’s economy, an investment that will pay dividends in the form of new jobs and new businesses. His support is crucial to our success, and we are very grateful to him.”

Preliminary work is now being done to build a utility tunnel to the future site of the nanotech center on W. Dickson St.; construction is expected to begin around the end of July.

June 24, 2009: As the economic downturn seizes up several nanoenabled product markets, growth has eroded all along the value chain to include nanointermediates and nanomaterials, according to a new report from Lux Research. The firm now projects sales from products incorporating nanotechnology should top $2.5T by 2015, but that’s -21% lower than what the firm had earlier predicted.

Basically, certain nanotechnologies will fare better or worse depending to their exposure to specific end markets — e.g. autos, construction, and electronics are faring worse in these sluggish times, while others — e.g. healthcare, life sciences — should “remain largely unscathed, and recover from the recession more quickly,” notes Jurron Bradley, senior analyst at Lux Research and lead author of the report, in a statement. The report is based on >1000 annual interviews and targeted talks with execs from 15 established companies and startups.

Key findings in the report:

  • Carbon nanotubes and ceramic nanoparticles will suffer due to their broad exposure in automotive and construction industries; nanocomposites and coatings will see big declines.
  • The US and Europe will still account for more than 2/3 of emerging nanotech revenue through 2015, but the new forecast sees each losing about 2%-3% share; Asia-Pacific sales will rise <5% due to its "relatively more competitive automotive industry," the analyst firm notes.
  • As the economy sputters, larger entrenched firms see opportunities to “renew and reposition” their offerings through bargain-basement M&A; meanwhile, “cash-strapped startups” need to conserve cash to wait until markets revive.
  • Changes to government nanotech initiatives will be needed to sustain jobs and GDP growth. “Rather than tax credits, they’ll need to offer more creative incentives like R&D grants to help struggling start-ups survive the recession,” Bradley says.


    • Shocks to the output of nanoenabled products ripple thorugh value chains. (Source: Lux Research, “The recession’s ripple effect on nanotech,” June 2009)

    June 24, 2009: Researchers from Denmark and China are now collaborating in several nanotech fields, including chemically manufactured electronic components and molecules that convert heat to electricity, reports the European Union’s Community Research and Development Information Service (CORDIS).

    Work at the new Center for Molecular Nano-electronics, joining efforts from the University of Copenhagen’s Nano-Science Center and Niels Bohr Institute and Beijing-based Chinese Academy of Sciences, broadly addresses molecular nanoelectronics. CORDIS notes two “opportunities for development” in particular: “the development of chemically manufactured computer electronics,” eyeing future application in computing, and “molecules with the capacity to convert heat to electric currents,” eventually creating heat emitters used in cars or factories.

    The two sides also are establishing a “common study program,” which would include an exchange program for students and researchers, building on a prior partnership; two Danish nanotech students previously studied in China for two months in 2007.

    “The new centre is an ideal framework to exchange researchers and equally importantly, research students, creating the best possible foundation for a fruitful research partnership,” explained Thomas Bjørnholm, a professor at the University of Copenhagen, in a statement.