Used in the manufacturing of solar cells, silicon wafers are an integral component that also create a sizable financial loss for the solar industry. About 5-10 percent of wafers get damaged during the production process, increasing the final cost of installed solar systems by billions of dollars each year. In an attempt to improve the efficiency of solar manufacturing, researchers at the National Renewable Energy Laboratory (NREL) have developed a device that detects weak or defective wafers before they reach the solar cell production stage.
Silicon wafers are used to produce solar cells, also known as photoelectric cells. Silicon acts as a semiconductor by absorbing the photons in sunlight that shine against the solar panel. The Silicon Photovoltaic Wafer Screening System, developed at the National Renewable Energy Laboratory (NREL) in Golden, Colorado, is a small furnace that can be integrated into the wafer assembly line. It detects defective wafers by exposing them to high temperatures. The temperatures are precisely calibrated according to the thickness of the wafer. Each wafer goes through a narrow, high-density illumination zone, with heat affecting its different strips and making the stress travel through the whole piece. The defective wafers are separated, then melted and recycled back into material for making new ones.
The new device could cut production losses and contribute to making solar cells more competitive within the energy market. A manual version of the device costs $60,000 and can test 1,200 wafers per hour. Apart from providing cheap wafer testing, the NREL instrument is also very energy-efficient.
Via Clean Technica
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