Thin-film photovoltaic (PV) manufacturer Ascent Solar Technologies has been selected by the U.S. Department of Energy (DOE) for two exclusive development projects. As part of the awards, worth up to $100,000 each, Ascent Solar is to work toward commercialization of sputtered Zn(O,S) buffers in flexible CIGS solar cells and also development of next-generation, high-efficiency Perovskite/CIGS Tandems cell. These projects are part of Ascent Solar’s plans for next-generation lightweight and flexible solar cells.
The first project will utilize sputtered Zn(O,S) buffers, which will help reduce costs and would further improve the environmental friendliness of our CIGS manufacturing process. The Perovskite/CIGS tandem junction project is designed to significantly improve efficiencies and drive further cost reduction by enabling a more complete conversion of the solar spectral energy into electricity.
“These are challenging yet exciting projects,” says Dr. Lawrence Woods, Director and Head of Research & Development for Ascent Solar. “While there are challenges to be overcome with the use of perovskite based devices, with already proven high-efficiencies, we believe that Ascent Solar is well positioned to incorporate these materials into our large-scale roll-to-roll processing.”
“We are honored to be the only PV developer and manufacturer to have been selected for the TCF projects, let alone two projects selected at the same time. This is a strong testament to the DOE’s faith in our ability to once again demonstrate our ‘lab-to-fab’ expertise,” says Dr. Joseph Armstrong, Chief Technology Officer and founding member of Ascent Solar Ascent Solar. “In both cases, we are leveraging our significant intellectual property with flexible monolithically integrated CIGS and teaming with the National Renewable Energy Laboratory (NREL) to inject their substantial knowledge in novel advanced materials to create a potentially substantial leap in the advancement of our product.”
The Office of Technology Transitions (OTT) and Technology Commercialization Fund (TCF) was created by the Energy Policy Act of 2005 to promote promising energy technologies. The TCF selections announced on August 23, 2018, will expand the DOE’s efforts to catalyze the commercial impact of the Department’s portfolio of research, development, demonstration, and deployment activities. TCF funds require a 50 percent match of non-federal funds from private partners.
Hanergy Thin Film Power Group signed a strategic cooperation agreement with Beijing Electric Vehicle at the “Green China – Hanergy Ecological City Comprehensive Solution Plan Conference” held at the Hanergy general headquarters. Working together within the framework of “Smart Transportation, Green Journey,” the two companies pledged to drive forward thin film applications for the car & household, including roofs and charging stations as well as projects to construct distributed energy industrial parks, and to use solar technology to alleviate poverty in agricultural areas.
As part of the agreement, BAIC BJEV will work with Hanergy to integrate Hanergy’s thin film solar solutions into the roofs of vehicles, providing auxiliary power and even functioning as the main power source. BAIC BJEV and Hanergy will also work together to use thin film solar technology to provide smart battery charging at electric vehicle charging stations. In terms of shared electric vehicles, the two companies will collaborate on using thin film solar to power automotive GPS and electronic locks.
Furthermore, BAIC BJEV and Hanergy plan to deploy thin film solar technology in BAIC BJEV’s automobile manufacturing plants, constructing a distributed green energy system to support factory operations. Finally, the two companies will begin to build small model villages incorporating the aforementioned technology, including thin film solar roofs, car charging stations and new energy vehicles. As part of this initiative the companies will also explore application of thin film solar for agriculture and poverty alleviation.
At the signing ceremony, Hanergy CEO Si Haijian said, “Hanergy’s partnership with BAIC BJEV stands as a model for cooperation between the thin film solar and the new energy vehicle industries, reflecting the push within Chinese industry to transform energy production and consumption.”
Aside from BAIC BJEV, the Green China Conference was attended by Haier, Zhong Yuan and other Chinese giants of industry. The conference was devoted to discussion of Hanergy’s Ecological City Comprehensive Solution, an effort under China’s new energy development strategy to lower urban energy consumption. This will be accomplished through reforms in macro level planning, program design, infrastructure construction and transportation services aimed at improving urban energy use. China’s efforts in this area follow similar programs undertaken in France, the Netherlands, Germany and other European countries. Similar to these countries, China has prioritized its plan to phase out gasoline powered cars.
Sol Voltaics has closed a record funding round of $21.3 million, the largest finance raise for a European solar technology company since 2015. The new finance will be used to accelerate commercialization of its highly anticipated solar efficiency boosting technology, SolFilm which the company claims will increase conventional solar panel efficiencies by up to 50%.
SolFilm, a patented, low cost thin-film which is comprised of billions of highly efficient Gallium Arsenide (GaAs) nanowires, enables solar panel manufacturers to reach efficiencies of up to 27 percent when integrated as a tandem-junction module. Having recently confirmed the successful manufacture of nanowires using their low-cost process Aerotaxy, Sol Voltaics is now in the final stages of technology optimization, with anticipated samples of its SolFilm being sent to partners by the end of 2018.
“This latest round of finance gives us the critical capital required to commercialize our efficiency boosting technology for the solar market,” said Erik Smith, Sol Voltaics CEO. “Having achieved our final major technology milestone with Aerotaxy earlier this year, we are now fully focused on reaching mass production of SolFilm. I’d like to thank our investors, both existing and new, for backing our vision and helping bring this revolutionary technology to the mass market.”
The latest funding features new investment from Norwegian company Watrium AS, alongside previous investors Kagra Gruppen AS, Nordic VC firm Industrifonden, FAM AB, Nano Future Invest, Blue Marlin AB and Teknoinvest AS. The investment brings total funding raised to $38m in the past 12 months, following the company’s $17m funding round in 2016.
The two leading thin-film solar manufacturers, First Solar and Solar Frontier, represent a combined manufacturing capacity of 4 GW. While they do not pose a short-term challenge to crystalline silicon players’ market dominance, ongoing innovations will ensure thin-film remains a significant player, according to Lux Research.
Of the two, First Solar is far bigger, with expertise in utility-scale systems and a new large-format module design that will help maintain its gigawatt-scale presence in utility-scale systems, as deployment grows in emerging markets. Solar Frontier has gradually diversified its business away from its home market of Japan and is making steps towards a rooftop building-integrated photovoltaic (BIPV) product.
“Both Solar Frontier and First Solar are moving forward to remain competitive with crystalline silicon. While First Solar will remain the thin-film leader, Solar Frontier has exhibited a willingness to form joint ventures to extend its scale,” said Tyler Ogden, Lux Research analyst and lead author of the report titled, “Tier-One Technology Tracker: Charting the Momentum of Thin-Film Leaders Solar Frontier and First Solar.”
Lux Research analysts compared Solar Frontier and First Solar, evaluating the two companies’ varied approaches, strengths and weaknesses. Among their findings:
• First Solar ahead on momentum. In Lux’s momentum analysis, First Solar had a score of 3.7, out of five, moving faster in technology progress and executing a competitive product strategy. Solar Frontier scored 2.9, moving adeptly into new markets through partnerships, while keeping pace in its financial position and manufacturing.
• Solar Frontier capitalizes on niches. Solar Frontier is taking steps toward a BIPV product, with preconfigured systems, flexibility and novel form factors. These are small differentiations in its current rooftop market, but can provide the groundwork for a larger BIPV industry with Solar Frontier at the helm, potentially a huge payoff.
• Challenges lie ahead for both. First Solar’s further growth hinges on plant-wide adoption of its Series 6 module and achieving systems costs below $1.00/W. Solar Frontier’s future rests on its ability to move its success in the lab to commercial production, and a partnership with a storage provider to integrate a lithium-ion battery option with its residential systems.
Next-generation solar cells made of super-thin films of semiconducting material hold promise because they’re relatively inexpensive and flexible enough to be applied just about anywhere.
Researchers are working to dramatically increase the efficiency at which thin-film solar cells convert sunlight to electricity. But it’s a tough challenge, partly because a solar cell’s subsurface realm — where much of the energy-conversion action happens — is inaccessible to real-time, nondestructive imaging. It’s difficult to improve processes you can’t see.
Now, scientists from the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) have developed a way to use optical microscopy to map thin-film solar cells in 3-D as they absorb photons.
The method, reported Nov. 15 in the journal Advanced Materials, was developed at the Molecular Foundry, a DOE Office of Science user facility located at Berkeley Lab. It images optoelectronic dynamics in materials at the micron scale, or much thinner than the diameter of a human hair. This is small enough to see individual grain boundaries, substrate interfaces, and other internal obstacles that can trap excited electrons and prevent them from reaching an electrode, which saps a solar cell’s efficiency.
So far, scientists have used the technique to better understand why adding a specific chemical to solar cells made of cadmium telluride (CdTe)—the most common thin-film material—improves the solar cells’ performance.
“To make big gains in photovoltaic efficiency, we need to see what’s happening throughout a working photovoltaic material at the micron scale, both on the surface and below, and our new approach allows us to do that,” says Edward Barnard, a principal scientific engineering associate at the Molecular Foundry. He led the effort with James Schuck, the director of the Imaging and Manipulation of Nanostructures facility at the Molecular Foundry.
The imaging method is born out of a collaboration between Molecular Foundry scientists and Foundry users from PLANT PV Inc., an Alameda, California-based company. While fabricating new solar cell materials at the Molecular Foundry, the team found that standard optical techniques couldn’t image the inner-workings of the materials, so they developed the new technique to obtain this view. Next, scientists from the National Renewable Energy Laboratory came to the Molecular Foundry and used the new method to study CdTe solar cells.
Inside the new method
To develop the approach, the scientists modified a technique called two-photon microscopy (which is used by biologists to see inside thick samples such as living tissue) so that it can be applied to bulk semiconductor materials.
The method uses a highly focused laser beam of infrared photons that penetrate inside the photovoltaic material. When two low-energy photons converge at the same pinpoint, there’s enough energy to excite electrons. These electrons can be tracked to see how long they last in their excited state, with long-lifetime electrons appearing as bright spots in microscopy images. In a solar cell, long-lifetime electrons are more likely to reach an electrode.
In addition, the laser beam can be systematically repositioned throughout a test-sized solar cell, creating a 3-D map of a solar cell’s entire optoelectronic dynamics.
What have we learned so far?
The method has already shed light on the benefits of treating CdTe solar cells with cadmium chloride, which is often added during the fabrication process.
Scientists know cadmium chloride improves the efficiency of CdTe solar cells, but its effect on excited electrons at the micron scale is not well understood. Studies have shown that the chlorine ions tend to pile up at grain boundaries, but how this changes the lifetime of excited electrons is unclear.
Thanks to the new imaging technique, the researchers discovered the cadmium chloride treatment increases the lifetime of excited electrons at the grain boundaries, as well as within the grains themselves. This is easily seen in 3-D images of CdTe solar cells with and without the treatment. The treated solar cell “lights up” much more uniformly throughout the material, both in the grains and the spaces in between.
“Scientists have known that cadmium chloride passivation improves the lifetime of electrons in CdTe cells, but now we’ve mapped at the micron scale where this improvement occurs,” says Barnard.
The new imaging technique could help scientists make more informed decisions about improving a host of thin-film solar cell materials in addition to CdTe, such as perovskite and organic compounds.
“Researchers trying to push photovoltaic efficiency could use our technique to see if their strategies are working at the microscale, which will help them design better test-scale solar cells—and eventually full-sized solar cells for rooftops and other real-world applications,” he says.