Natcore claims new solar cells achieve commercial-level efficiency
Refinement of Natcore’s all-back-contact silicon cell structure, which utilizes low-cost aluminum instead of high-cost silver, has continued. Less than 11 months ago, early proof-of-concept cells were delivering 4% efficiencies. Today, the cells have already reached efficiencies of 17.5%, which is roughly equivalent to typical commercial cells being sold today.
Natcore’s cell design is producing short-circuit currents above 40 mA/cm2 and open-circuit voltages above 0.65V. Expected improvements in these measurements, as well as fill factor, project to efficiencies well above 20%.
Natcore’s design builds upon the basic concept of a silicon heterojunction (SHJ) solar cell. An SHJ cell produced by Panasonic claims to hold the current world record efficiency for a silicon solar cell at 25.6%. Natcore claims that there is nothing inherent in the company’s design that would preclude it from ultimately achieving efficiencies in this range.
The rapid improvements in performance for Natcore’s SHJ cells have been made in the company’s Rochester research facilities, which, while employing advanced laser and processing equipment, are somewhat limited in comparison with commercial solar cell production facilities. The company believes higher performances will be achieved as development of Natcore’s cells progress from the lab to production facilities.
Natcore’s laser processed, all back contact solar cell technology will accelerate the introduction of a new generation of solar panels that claim to be more efficient than current solar panels and will be lower in cost. Part of the output gain will come from eliminating the reflecting metal contact strips on the top of the cell, thereby increasing the amount of light absorbed by the panel, and part of it will come from reducing cell-to-module losses, i.e., the electrical losses that occur when the cells are electrically connected to each other using the small metal ribbons that are today’s technology. The result will be an improvement of panel efficiency by as much as 8% to 10% compared to today’s products. The panel cost reduction comes partly from replacing the cost of silver with the cost of aluminum and partly from the reduced handling needed for an all back contact panel assembly compared to a standard panel.
“Many companies are producing cells with efficiencies at the levels we’ve so far achieved,” said Dr. David Levy, Natcore’s Director of Research and Technology. “But cells made using our technology will ultimately be much more efficient and far less expensive to produce, which will equate to very significant cost/watt improvements.”
The Natcore structure uses a high-volume aluminum metallization that can be low in cost and its current efficiencies are now in the range of commercial production.
“We have reached performance goals that make us ready to present our case to large manufacturers whose scale and resources can help us reach the ultimate, ultra-high-efficiency potential that our cells are capable of,” said Chuck Provini, Natcore’s president and CEO.