3-D: The New Word in Solar Cells

The new competitive battleground in solar cells is 3-D.

Rather than produce flat solar cells, a slew of relatively new – and until now relatively silent – companies will try to improve the efficiency and economics of solar by making solar panels and/or cells that are curved or that sport curved components.

The advantage of adding more shape to the cell comes in operating time. Planar solar cells can only capture sunlight for a few limited hours. The sun is too low in the sky during the morning and afternoon hours for a planar solar panel to work at optimal efficiencies. You can put these panels on a tracker that moves with the sun, but that adds cost.

Because of their shape, curved solar cells can better harvest early morning or late afternoon light. (Think of it for a second – at least part of the active surface will directly face the sun as long as it is in the sky.) Solyndra, which came out of stealth mode today, has a cylindrical solar cell activated with copper indium gallium selenide.

But Solyndra isn’t alone. Bloo Solar has come up with a planar solar cell that contains cylindrical solar brushes that harvest light. Under an electron microscope, the brushes look like bristles from a toothbrush. Although the cells are flat, the brushes allow it to exploit the 3-D effect. The Sacramento, Calif.-area company hopes to be in mass production in 2011. (Bloo will also present at End-to-End Electricity sponsored by Greentech Media in November.)

Meanwhile, over in Denmark, Sunflake is working on a III-V solar cell that it says achieves 30-plus percent efficiencies. Inside the solar cell tree-like structures harvest light. The material was discovered by accident during an experiment at the Niels Bohr Institute. It is currently seeking a Series A round of funding.

Solexel is also doing something in 3D, my colleague Eric Wesoff tells me. Clearly, something is going on.