Natcore will develop a black silicon line, including equipment, chemicals, and the solar cells, under a patent license agreement from NREL. Black silicon does not reflect light, thanks to nano-scale pores etched in the silicon surface, which Natcore will passivate with a liquid-phase process.
December 27, 2011 – PRNewswire — Natcore Technology Inc. (TSX-V: NXT; NTCXF.PK) will develop a black silicon line, including equipment, chemicals, and solar cells, under a patent license agreement from the US Department of Energy (DOE) National Renewable Energy Laboratory (NREL). Black silicon does not reflect light, thanks to nano-scale pores etched in the silicon surface.
Natcore has an exclusive license to NREL’s patents on diffused emitters with liquid-phase passivation. Along with the patent agreement, Natcore and NREL will create commercial prototypes based on black silicon, under a Cooperative Research and Development Agreement.
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Black-silicon-based solar panels could have significantly higher power output than traditional silicon solar panels with antireflective (AR) coatings, because the reflectance and the angular dependence of the reflectance from black silicon are lower. NREL and Natcore measure silicon solar cell reflectivity at 40% (uncoated), dropped to 6% by AR coating, while black silicon reflectivity is less than 1.5% (In image above, L to R: uncoated Si solar cell, black Si solar cell, and AR-coated solar cell, provided by NREL). Angular dependence is important for power conversion in morning and afternoon hours, when sunlight hits a flat solar module at an angle.
Natcore uses its liquid-phase deposition (LPD) passivation to overcome the limitation of black silicon — significantly more exposed silicon than traditional cells due to the porous surface. Dr. Dennis Flood, Natcore’s CTO, says that, “before Natcore’s passivation technology, it was necessary to put coated cells into a 1000C furnace to create a thermal oxide. Natcore’s LPD silica coating achieves passivation without requiring an extra thermal process.”
Prior to the licensing agreement, NREL sent black silicon wafers with junctions?unfinished cells?to Natcore. Natcore coated them with SiO2 and passivated them. NREL then applied contacts and tested the completed cells in their labs in Golden, CO. According to Flood, the result persuaded NREL to grant Natcore a license to develop and commercialize products based on the NREL black silicon technology.
Natcore will optimize the combined processes and incorporate them into its AR-Box fab device, which allows for all-liquid phase processing of ultra-low-reflectivity, high-performance silicon solar cells at high volumes.
The NREL license contains a development and commercialization plan that establishes technical and market milestones for Natcore, along with a royalty structure. These are subject to confidentiality provisions set by the parties. The technical milestones include solar cell efficiency goals, some of which are to be met by August of 2012. The market milestones include commercial sale dates and dollar targets. The agreement is dated December 12, 2011, and is effective for as long as the NREL patents are enforceable.
NREL is the U.S. Department of Energy’s primary national laboratory for renewable energy and energy efficiency research and development. NREL is operated for DOE by the Alliance for Sustainable Energy LLC. Learn more at www.nrel.gov.