JA Solar has recently launched two new high-efficiency PV modules at the recent PV Expo in Japan: the 285W PERCIUM module and the 270W RIECIUM module. The announcement marks the first time a top-tier solar company has adopted black silicon technology into a commercial product (RIECIUM).
To maximise the absorption of light in a silicon solar cell, PV manufacturers aim to reduce the reflection of light from the cell surface. This is typically done by a combination of 2 approaches: (a) surface texturing, which reduces reflection to about 15%, and (b) adding an anti-reflection coating, which further reduces reflection down to about 6% (and gives solar cells their deep blue colour).
However, by creating spiked patterns on the surface of the silicon (see image below), it is possible to reduce this reflection down to the 1.5-2% level. Since very little light is reflected off the surface of the silicon, it appears black – hence the name, “black silicon”.
Image Credit: Feng Liu et al / Optical Devices in Communication and Computation
JA Solar’s black-silicon enabled RIECIUM module has a cell efficiency of 18.3% and module rating of 270W, which represent a 4% cell efficiency improvement and a 5W module power improvement compared to standard mono-crystalline silicon modules. The modules are also expected to have superior reliability compared to standard modules due to more rigorous testing beyond required standards.
While JA Solar is the first major company to adopt the technology, it may not be the only one. Natcore Technology, which developed a chemical process for black silicon fabrication in conjunction with the National Renewable Energy Laboratory (NREL) in 2012, announced a few months ago that is working to develop low-cost solar cells using the technology. Natcore’s simplified process reduces reflection levels down to 2% while completely eliminating the anti-reflection coating, which has the potential to reduce solar cell production costs by up to 23.5%.
The cost-cutting potential of black silicon is enormous according to Natcore CEO, Chuck Provini, who says, “A recent article by Shyam Mehta, senior solar analyst of GTM Research (‘Technology not materials to drive down Chinese solar costs,’ August 2013), predicts that Chinese manufacturers will be able to cut prices by only one cent in the next year or so. We could quadruple those savings in one fell swoop”.
Optimistic about the technology, Provini says, “Black silicon seems poised to become the industry’s standard approach”. If JA Solar’s announcement is anything to go by, perhaps there’s some truth to that after all.
Top Image Credit: Natcore Technology
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