Highly purified silicon represents up to 40 percent of the overall costs of conventional solar-cell arrays — so researchers have long sought to maximize power output while minimizing silicon usage. Now, a team at MIT has found a new approach that could reduce the thickness of the silicon used by more than 90 percent while still maintaining high efficiency. The secret lies in a pattern of tiny inverted pyramids etched into the surface of the silicon. These tiny indentations, each less than a millionth of a meter across, can trap rays of light as effectively as conventional solid silicon surfaces that are 30 times thicker.
The new findings are being reported in the journal Nano Letters in a paper by MIT postdoc Anastassios Mavrokefalos, professor Gang Chen, and three other postdocs and graduate students, all of MIT’s Department of Mechanical Engineering.
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