The U.S. Department of Energy (DOE) today announced that DOE will invest up to $13.7 million, over three years (Fiscal Years 2008 – 2010), for 11 university-led projects that will focus on developing advanced solar photovoltaic (PV) technology manufacturing processes and products. These projects are integral to President Bush’s Solar America Initiative, which aims to make solar energy cost-competitive with conventional forms of electricity by 2015. Increasing the use of solar energy is also critical to diversifying our nation’s energy sources in an effort to reduce greenhouse gas emissions and dependence on foreign oil. Combined with a minimum university and industry cost share of 20%, up to $17.4 million will be invested in these projects.
“Harnessing the natural and abundant power of the sun and more cost-effectively converting it into energy has enormous potential to help reduce greenhouse gas emissions and provide greater stability in electricity costs,” DOE Assistant Secretary for Energy Efficiency and Renewable Energy Alexander Karsner said. “These projects will not only bolster innovation in photovoltaic technology, but they will help meet the President’s goal of making clean and renewable solar power commercially viable by 2015.”
Universities selected for these projects will leverage fundamental understanding of materials and PV devices to help industry partners advance manufacturing processes and products. These projects have the potential to significantly reduce the cost of electricity produced by PV from current levels of $0.18-$0.23 per Kilowatt hour (kWh) to $0.05 - $0.10 per kWh by 2015 – a price that is competitive in markets nationwide. Each university will work closely with an industry partner to ensure the projects retain a commercialization focus and that results are quickly transitioned into market ready-products and manufacturing processes. Additionally, students will be exposed to diverse PV-related commercialization efforts, enhancing workforce development in an effort to increase competitiveness and retain qualified scientists in the growing domestic PV research and development industry.
Photovoltaic-based solar cells convert sunlight directly into electricity, and are made of semiconductor materials similar to those used in computer chips. When sunlight is absorbed by these materials, the solar energy knocks electrons loose from their atoms, allowing the electrons to flow through the material to produce electricity. The process of converting light to electricity is called the photovoltaic effect.
Projects were selected in response to DOE’s June 20, 2007, Funding Opportunity Announcement – University Photovoltaic Process and Product Development Support - which seeks to strengthen university involvement in the rapidly growing PV industry. Negotiations between selected applicants and DOE will begin immediately to determine final project plans and funding levels. Funding is subject to appropriations from Congress. Selected projects include:
Arizona State University (Tempe, AZ) with SolFocus and Soliant Energy: Reliability Evaluation of Concentrator Photovoltaics per IEC Qualification Specifications. The recent boom in concentrating PVs has created a significant backlog of products waiting to undergo IEC product testing. This project will focus on reducing bottlenecks of the qualification test such as environmental chamber testing while enhancing scheduling and coordination with industry to significantly increase testing throughput and efficiency. DOE will provide up to $625,304 for this approximately $800,000 project.
California Institute of Technology (Pasadena, CA) with Spectrolab: 100 millimeter (mm) Engineered InP on Si Laminate Substrates for InP based Multijunction Solar Cells. Indium Phosphide (InP) is a very desirable substrate to form multijunction solar cells upon but is cost prohibitive even for high performance cells. This project aims to reduce InP layer thickness by a factor of ten by bonding a thin layer of InP to an inexpensive silicon laminate substrate enabling a cost-effective, scaleable InP-based multijunction cell process. In turn, this will open a new design space for high efficiency multijunction solar cells. DOE will provide up to $837,000 for this approximately $1 million project.
Georgia Institute of Technology (Atlanta, GA) with Sixtron: Rear Contact Technologies for Next- Generation High-Efficiency Commercial Silicon Solar Cells. Performance-enhancing cell processing techniques are well established in the silicon industry but most are associated with higher processing costs, which may not be justified by the marginal increase in efficiency. This project will develop enhanced, cost-effective back surface passivation, light trapping, and inkjet-printed back contacts, to yield a complete, low-cost, cell process which produces 17-20% efficient devices that are ready for direct commercialization. DOE will provide up to $1.5 million for this approximately $1.9 million project.
Massachusetts Institute of Technology (Cambridge, MA) with CaliSolar, Inc. and BP Solar, Inc: Defect Engineering, Cell Processing, and Modeling for High-Performance, Low-Cost Crystalline Silicon Photovoltaics. This project will characterize defects and engineer their distribution within a solar cell to close the efficiency gap between industrial multicrystalline and high-efficiency monocrystalline silicon cells, while preserving the cost advantage of these low-cost, high–volume substrates. The project is targeting 18-22% efficient cells at manufacturing costs of less than $1 per peak watt. DOE will provide up to $1.5 million for this approximately $1.9 million project.
North Carolina State University (Raleigh, NC) with Spectrolab: Tunable Narrow Bandgap Absorbers for Ultra High Efficiency Multijunction Solar Cells. Conversion efficiency of multijunction cells can be increased by balancing each layer’s responsiveness to the sun’s broad spectrum and by matching the current produced by each layer. This project will pursue both of these improvements by developing and optimizing a 1-1.5 electron volt, graded strain subcell layer and then integrating this layer into Spectrolab’s triple junction stack to produce a four-junction solar cell. This project is targeting a world record efficiency of 45%. DOE will provide up to $1,147,468 for this approximately $1.4 million project.
Pennsylvania State University (University Park, PA) with Honeywell: Organic Semiconductor Heterojunction Solar Cells for Efficient, Low-Cost, Large Area Scalable Solar Energy Conversion. Organic solar cells hold promise to drastically lower costs but currently have low conversion efficiencies due to drawbacks in the structure of the junction interface. This project will focus on using highly ordered, high-surface area titanium dioxide nanotube arrays in combination with organic semiconductors to fabricate low-cost solar cells with efficiencies of greater than 7%. DOE will provide up to $1,231,843 for this approximately $1.5 million project.
University of Delaware Institute of Energy Conversion (Newark, DE) with Dow Corning: Development of a Low-Cost Insulated Foil Substrate for CIGS Photovoltaics. Currently, direct formation of flexible Copper Indium Gallium Selenium (CIGS) modules is limited by the lack of an inexpensive substrate capable of withstanding the high processing temperatures required to produce quality films. This project will address this limitation by targeting development of a low-cost stainless steel flexible substrate coated with silicone-based resin dielectric and module processes applicable across a variety of roll-to-roll CIGS manufacturing techniques. The project will target devices based on this substrate with efficiencies greater than 12%. DOE will provide up to $1,478,331 for this approximately $1.85 million project.
University of Delaware (Newark, DE) with SunPower: High Efficiency Back Contact Silicon Heterojunction Solar Cells. This project will deposit amorphous silicon (a-Si) films on crystalline cells to enhance the electrical properties and enable low-temperature processing. Metal contacts will be moved to the back of the cell to increase the amount of light entering the cell and increase conversion efficiencies beyond 26%. DOE will provide up to $1,494,736 for this approximately $1.9 million project.
University of Florida (Gainesville FL) with Global Solar Energy Inc., International Solar Electric Technology Inc., Nanosolar Inc., and Solyndra Inc: Routes for Rapid Synthesis of CIGS Absorbers. This project will develop predictive models that quantitatively describe the formation of CIGS films under different processing conditions. These models can be used to develop optimal processing recipes which will reduce processing time and identify scaling issues for commercial manufacturing. The project is targeting a CIGS synthesis time of less than two minutes. DOE will provide up to $599,556 for this approximately $800,000 project.
University of Toledo (Toledo, OH) with Calyxo USA, Inc: Improved Atmospheric Vapor Pressure Deposition to Produce Thin CdTe Absorber Layers. Record cadmium telluride (CdTe) thin film devices utilize an 8-micrometer (µm) thick CdTe layer but duplication of this structure in commercial manufacturing increases material costs and deposition time. This project will reduce the CdTe layer thickness to approximately 1-µm while targeting a 10% module efficiency. Improvements to contacts, uniformity, and monolithic integration will also be achieved. DOE will provide up to $1,164,174 for this approximately $1.7 million project.
University of Toledo (Toledo, OH) with Xunlight: High-Rate Fabrication of a-Si-Based Thin-Film Solar Cells Using Large-area VHF PECVD. Reducing processing costs of amorphous silicon modules has proven difficult because increasing process throughput of conventional deposition processes results in lower device efficiency. This project aims to retain high efficiencies while fabricating high efficiency amorphous silicon and nanocrystalline silicon solar cells at high rates. The project will target 10% conversion efficiency for amorphous silicon/nano crystalline silicon (a-Si/nc-Si) solar cells. DOE will provide up to $1,442,266 for this approximately $1.9 million project.