RED BANK, N.J. - Scientists at Natcore Technology Inc. (TSX-V: NXT; NTCXF.PK) have created the world's first black silicon solar cell using processes amenable to low-cost mass production.
After recently treating a wafer to make it the "blackest" silicon solar cell surface ever recorded, Natcore's technicians used their scalable liquid phase deposition (LPD) process to create the black silicon solar cell, from wafer to finished cell, in their R&D Center in Rochester, N.Y.
In the past, Natcore had directed other labs--e.g. Arizona State University, the Photovoltaic R&D Center at the University of Toledo, the U.S. Department of Energy's National Renewable Energy Laboratory (NREL)--to perform various production steps or to conduct tests for which Natcore was not equipped.
But in July, Natcore completed a $2.5 million financing to enable the company to take its black silicon technology to commercialization. A portion of the proceeds was invested in the brainpower and lab equipment needed to execute its work quickly and in-house. "This black silicon solar cell, made entirely in our lab, is the first fruit of that investment," says Chuck Provini, Natcore President and CEO.
While Natcore's "Absolute Black" silicon wafers have near-zero reflectivity, meaning that virtually 100% of the light that reaches them is available for conversion to electricity, these wafers are merely components of a solar cell; they do not generate electricity until fashioned into solar cells.
The next stop for Natcore's new solar cell is NREL, with which Natcore has a Cooperative Research & Development Agreement (CRADA). NREL recently produced solar cells with an efficiency of 18.2% using processes that are less suited to mass production. Under the terms of the CRADA, NREL and Natcore will work together using Natcore's low-cost passivation technology to achieve or exceed that efficiency with Natcore's black silicon solar cells.
This goal would be accomplished by combining Natcore's patented LPD technology with NREL's technologies for creating a black silicon antireflective layer integrated into high-efficiency solar cells. The feasibility of the combined technologies working together has already been demonstrated in a preliminary Natcore/NREL effort that produced a small-area, lab-scale black silicon solar cell with 16.5% efficiency.
Dr. Hao-Chih Yuan, NREL Research Scientist, says "We have a good synergy with Natcore on black silicon technology. A silicon surface, without proper coating, is detrimental to the energy conversion efficiency of the solar cell. It is not unusual to grow silicon dioxide coatings on black silicon surfaces for this purpose, but the growth is typically at very high temperatures. Natcore's coating uses chemistry. They are the ones who can passivate a black silicon surface cheaply."
Eric Payne, NREL's Senior Licensing Executive adds, "Natcore is the nearest-term and best partner for commercialization of the black silicon technology."
Provini says, "NREL holds the efficiency record with black silicon, but they used a passivation technology that requires expensive thermal oxidation. We will replace that cumbersome step with our LPD oxide process. We believe the combination of the two technologies could significantly exceed NREL's record cell efficiency."
In December 2011, Natcore was granted a patent license agreement from NREL to develop and commercialize a line of black silicon products, including equipment, chemicals, and solar cells, based on NREL patents. The license grants Natcore exclusivity in the field of diffused emitters with liquid phase passivation.
Natcore's "Absolute Black" silicon wafers are significant for two reasons. First, they yield a tenfold reduction in reflectance, which mean that up to 3% more usable light would get into the solar cell, effectively increasing the cell efficiency by that amount. Second, a panel made from Absolute Black solar cells should produce significantly more energy on a daily basis than will a panel made from cells using the industry standard antireflective coating. That's because it reflects less light and because it should perform better during the morning and afternoon hours when the sun hits at an angle. (It should also outperform standard cell panels on cloudy days.) "Its higher energy output, combined with a lower cost using Natcore's patented process, could quickly make black silicon the global solar technology of choice," adds Provini.
Natcore's Chairman, Brien Lundin, notes "This is a major milestone for Natcore and the entire solar industry. A low-cost, scalable production process was the missing piece in making black silicon solar cells viable. We now look forward to providing this key capability."
Contact: Chuck Provini
Natcore Technology Inc.