Groovy solar: Facets etched into the surface of wires redirect incoming light so that it is absorbed by a solar cell rather than reflected away. The wires serve to collect current generated by a solar cell.
The second innovation involves the silver wires that harvest electrical current generated by the silicon. Sachs has developed a method for making these wires as small as one-fifth the width of the wires that are typically used, while improving their conductivity. The thinner wires use less silver, which cuts down costs. Also, because the wires are thinner, they can be spaced closer together and still block less light than ordinary wires can. The closer spacing makes the wires more efficient at collecting electrical current generated in the silicon.
The final improvement has to do with a set of wide, flat wires used to collect current from the thin silver wires. These bars typically block light entering the cell, reducing efficiency. But Sachs has etched their surfaces so that they act as faceted mirrors. This achieves an effect similar to the texturing of the silicon surface. While the improvements add costs in some ways, the increases are offset by savings elsewhere, such as from using less silver, Sachs says.
While 1366 Technologies plans to manufacture its own cells, Sachs says that it is also open to licensing the technology to other solar-cell makers. Ultimately, Sachs hopes that his technology will speed the adoption of solar power to meet global energy requirements. “We need an exponential growth curve now,” he says. “Not 15 years from now–that’s too late.”
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