Scientists at New York-based Natcore Technologies have developed the ‘blackest’ solar cell ever that reflects just 0.3 percent of sunlight.
Reducing the amount of reflected sunlight is one way to make PV modules more efficient – that’s why, for now, an antireflective coating is an essential component of solar cells.
Natcore scientists have perfected this technology through two methods: chemical etching, and a proprietary liquid phase deposition (LPD) process, resulting in a black silicon PV panel with near-zero reflectivity. The two methods are cost-effective and nontoxic.
According to Natcore, a ten-fold reduction of reflectivity in solar cells can yield up to 3 percent more usable light, with an identical boost in PV cell efficiency.
“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,” said Chairman Brien Lundin.
The silicon wafers absorb virtually 100 percent of the sunlight striking the cell, making it available for conversion to electricity. However, wafers are only part of the finished product, and need to be constructed into solar cells to be able to convert sunlight to electricity.
The next stage for the black solar wafers is solar cell assembly at the National Renewable Energy Laboratory (NREL). Natcore and NREL have already produced a solar cell with 18.2 percent efficiency, but this black solar cell was made using a thermal deposition process that is too expensive for commercial production.
But using Natcore’s low-cost technology, NREL and Natcore hope to exceed that efficiency with the black silicon solar cells. The black PV cell has already demonstrated its practical use through a test-run: a small, laboratory-scale black silicon solar cell with 16.5 percent efficiency.