Natcore Technology Inc. announced major strides in advancing its black silicon solar cells to commercial levels of efficiency and, as part of its development process, has discovered that its technology could finally provide a low-cost selective emitter application.
Natcore’s initial black silicon solar cells, the first full-size black silicon cells produced using a low-cost, scalable manufacturing process, had efficiencies of approximately 1 percent, as compared with average efficiencies for commercial cells of approximately 17 percent.
Through refinement of its in-lab production process, and despite the lack of a key piece of equipment, Natcore’s technical staff has been able to achieve efficiencies as high as 14.7 percent.
These results have been achieved without an adequate diffusion furnace to control phosphorus diffusion into the solar cells’ silicon surfaces. Natcore has now obtained and installed a fully capable diffusion furnace, with commissioning of this crucial piece of equipment having begun the week of April 1, 2013. The company’s technical staff is confident that this diffusion furnace will allow for significant improvements in the efficiencies of its black silicon cells.
Importantly, Natcore’s staff has discovered that its proprietary liquid phase deposition (LPD) may make a low-cost selective emitter application available to the solar industry. Selective emitter technology is a long-sought enhancement to solar cells in which the regions under a cell’s front contacts are heavily doped to improve the electrical connection, while the remaining emitter surface is lightly doped to promote better efficiency.
Selective emitter applications have been proven to significantly increase solar cell efficiencies, but a low-cost, highly scalable process has remained elusive to industry. Theoretically, Natcore’s LPD process could make this achievable, and early results from experiments using the company’s newly installed diffusion furnace have been very encouraging.
Because of these positive results, Natcore is now rapidly moving to protect its selective emitter intellectual property, and is in the process of filing provisional patents.
"The solar industry has been clamoring for a selective emitter application that is cost-effective because of its demonstrated improvement to cell efficiencies," notes Natcore’s CEO, Chuck Provini. "In fact, once Dr. Daniele Margadonna joined our Science Advisory Board and learned of our plans to install a new diffusion furnace, he immediately urged us to simultaneously pursue a selective emitter approach. I’m pleased to say that we were very quickly able to demonstrate the efficacy of our technology toward this crucial and valuable application."
Natcore’s black silicon and selective emitter applications are not mutually exclusive; in fact, they are synergistic. Indeed, the envisioned production process would allow both of these important improvements to be seamlessly inserted into a solar cell manufacturing line.
"Combining Natcore’s black silicon technology with our groundbreaking selective emitter technology could raise today’s commercial solar cell efficiencies to new high levels, while still lowering the cost per watt," says Natcore’s Chief Technology Officer, Dr. Dennis Flood. "Solar cell manufacturers are aggressively seeking easy-to-implement production steps that will improve their product and profitability without having to raise their prices. Natcore’s combination of selective emitter and black silicon technologies promises to do just that."