1366 Technologies

Via Jim Fraser1, we learn from Kevin Bullis2 that an MIT researcher has developed a new, multi-crystalline, solar cell that is 27 percent more efficient without being more expensive to make.

Emanuel Sachs, a professor of mechanical engineering, is one of the founders of 1366 Technologies, which announced its first round of funding of $12.4 million from Venture capitalists co-led by North Bridge Venture Partners and Polaris Venture Partners. The company plans to build a pilot-scale manufacturing plant in about a year.

Professor Sachs previously invented the String ribbon™ wafer technology being commercialized at Evergreen Solar, a leading developer of solar energy products. Sachs is joined by 1366 Technologies co-founder and investor, Frank van Mierlo, who serves as the company’s president. Harvard Business School professor Joseph Lassiter rounds out the board of directors, all of whom hold degrees from MIT.

Light_capturing_ribbon


Flat wires on the surface of a solar cell collect electrical current. Ordinarily, such design reduces efficiency since some light is prevented from reaching an active area where the photons are converted to electrical energy, 1366 Technologies has a new design, which traps much of the light that would have been reflected. The new approach improves performance without increasing cost.

As previously noted, a principle advantage of the concentrating optics is that a much smaller solar cell can be used. There is a cost savings since the prices have risen with the growing demand for solar and a shortage of pure silicon. The use of a low cost, non-imaging optics also can make more practical the application of more expensive, advanced, high-efficiency solar cells

Sachs says that current solar cells cost about $2.10 per watt generated. When manufactured at a commercial scale, the first cells incorporating his new technology will cost $1.65 per watt while planned improvements will reduce the cost to about $1.30 a watt.

The company’s solar cells include three key innovations to improve efficiency:

  1. A method for adding texture to the surface of the cells that allows the silicon to absorb more light.
  2. A method for making the current collecting wires as small as one-fifth the width of the wires that are typically used, while improving their conductivity.
  3. A new Light-Capturing Ribbon that increases the efficiency of a solar module by reflecting light back onto the surface of the cell. This grooved ribbon replaces the traditional wires used to interconnect solar cells.

Energy Blog commentator Paul Dietz observes that “textured silicon is an old idea for PV cells.”

It works because the refractive index of Si is very high (3.5, iirc, although it depends on wavelength) and so unless the outgoing light hits the surface at near normal incidence, it will be reflected back into the cell. This enables one to greatly reduce the cell thickness, improving its efficiency.

It’s even more important for PV cells made from direct bandgap semiconductors (GaAs, say), where carrier recombination can cause reemission of light. You want that light to be trapped and reabsorbed.

Continue reading here: Alternative Fuel Analysis

Was this article helpful?

0 0