Rochester Institute of Technology spinoff Wakonda Technologies will use a $9.5 million Series A venture round announced today to pursue a new technique for manufacturing photovoltaic cells that are more efficient but cost less than mass-market solar cells. Backers for the startup, which is moving from New York state to Medford, MA, include Advanced Technology Ventures, General Catalyst Partners, Polaris Venture Partners, the Massachusetts Green Energy Fund, and Applied Ventures, the venture capital arm of Applied Materials.
Wakonda was founded last year in upstate New York; co-founder and chief technology officer Ryne Raffaelle is the director of RIT’s NanoPower Research Lab. The company, which won a “Clean Energy Entrepreneur of the Year” award last November from the U.S. Department of Energy’s National Renewable Energy Laboratory, hopes to build cells that can be incorporated into solar concentrators or rooftop systems for residential and commercial buildings.
Wakonda is just one among a herd of new venture-funded startups—several based here in New England—that are developing lower-cost, higher-efficiency solar cells. But Bill Wiberg, a general partner at Advanced Technology Ventures, said in a statement that Wakonda’s technology (the details of which remain sketchy) is different. “In a market filled with innovative ideas, Wakonda’s approach for producing low cost, high efficiency solar cells stood out as having breakthough potential,” Wiberg said.
Roughly speaking, today’s photovoltaic (PV) cells come in three tiers, with the most efficient cells naturally being the most costly:
Tier One: Single-crystal cells made from rare, expensive semiconductor materials such as gallium arsenide. These cells, developed for special applications such as satellites, convert up to 30 percent of the energy from the sun into electricity, but they cost more than $10,000 per square meter.
Tier Two: Multi-crystalline cells made from silicon, the same material used to manufacture virtually all semiconductor-based electronics. About 90 percent of commercial solar cells are made from this rigid material, which costs about $1,000 per square meter and has an efficiency ranging between 9 percent and 20 percent.
Tier Three: Flexible, thin-film solar cells made from amorphous (non-crystalline) silicon, cadmium telluride, copper indium diselenide, or other materials deposited on flexible substrates such as organic polymers or stainless-steel foil. These materials can be made in high volumes using a roll-to-roll process, but typically have lower efficiency, ranging from 5 percent to 8 percent. Companies developing thin-film solar cells are aiming for a cost of about $50 per square meter.
Wakonda says it’s working on a best-of-both-worlds technology that would combine the high power efficiency of Tier One with the low manufacturing cost of Tier Three. According to Wakonda’s website, the company’s intellectual property hinges on a “virtual single crystal” technology that emulates the high efficiency of single-crystal cells without using expensive and toxic materials like gallium arsenide. The technology involves “a proprietary surface treatment that allows a low cost, commercial metal foil to simulate an expensive single crystal wafer,” according to the site.
Company materials indicate that the foils will be manufactured using a continuous, roll-to-roll process, which is seen as cheaper than conventional Tier One or Tier Two methods that involve baking photovoltaic materials in large batches and then cutting them up. But the company hasn’t yet said how much the foils will cost, or how efficient they’ll be. ATV’s Wiberg told CNET’s Martin LaMonica today that Wakonda plans to have a proof-concept device ready within 12 months.
Three local Wakonda competitors that we’ve covered here at Xconomy include Lexington, MA-based 1366 Technologies, which is making multicrystalline solar cells with a new architecture using internal reflections, metallization, and surface textures to improve efficiency; Marlborough, MA-based Evergreen Solar, which is developing a “string ribbon” technique for manufacturing large PV cells and panels at lower cost; and Lowell, MA-based Konarka, which makes “PowerPlastic” flexible PV strips made from electrically conductive organic polymers.
Then there’s Sudbury, MA-based Vanguard Solar, which is developing a chemical bath deposition process for coating carbon nanotubes in a crystalline semiconductor film that, according to the company, will have an efficiency comparable to single-crystal photovoltaic cells. And the region is also home to at least two major suppliers of industrial equipment for the solar industry: Merrimack, NH-based GT Solar, which sells fabrication equipment lines for multi-crystalline PV wafers and cells, and Bedord, MA based Spire Solar, whose equipment is used to make, test, interconnect, and finish PV panels.
