THIN FILM EFFICIENCY EDGES UP

Increasing efficiency of a solar cell from 21.9% to 23.2% may not seem significant but it is not a 1.3% improvement, it is converting almost 6% more of the sunlight hitting the thin film into electricity.

The materials added to the thin film to achieve this improvement are not expensive. The result: More electricity for little more cost, lowering the overall cost of installing solar energy.

Most scientists believe the solar materials currently in use are near the limits of their efficiency capacity so small incremental improvements are all that are expected until somebody figures out how to do with common, inexpensive materials what can already be done with rare, costly materials like platinum.

Footnote: The article mentions research support from the Fraunhofer Institute. Seems rare that anything happens in solar research these days that doesn’t involve the Fraunhofer Institute. That could have something to do with why Germany is the world leader in solar energy. The good news: Fruanhofer just hooked up with MIT to do something in the U.S. (See MIT AND FRAUNHOFER ANNOUNCE CENTER)

Research is driving the march toward price parity. (click to enlarge)

New efficiency record for solar cells
May 14, 2008 (PhysOrg)

WHO
Bram Hoex, PhD in Physics, Eindhoven University of Technology; Professor Richard van de Sanden and Associate Professor Erwin Kessels, the Plasma & Materials Processing (PMP) research group, Eindhoven University of Technology; Fraunhofer Institute

Adding a tiny layer of aluminum oxide makes a significant difference. (click to enlarge)

WHAT
Hoex announced the improvement of crystalline silicon solar thin film efficiency from 21.9% to 23.2%.

WHEN
- The research project won Hoex his PhD in Applied Physics last week.
- The Eindhoven University announcement of Hoex’s achievement reports that solar cell generated electricity is expected to reach cost parity with other forms of electricity generation in 10 to 15 years.

Being common and cheap gives silicon a market advantage. (click to enlarge)

WHERE
The layer of aluminum oxide deposits a density of negative charges near the solar cell’s surface, preventing losses of charged electrons in that direction and channeling them into the flow of electricity.

WHY
- The improved efficiency was the result of using an ultra-thin (30 nanometer) aluminum oxide layer in the solar cell.
- The Van de Sanden and Kessels group, specializing in plasma deposition of extremely thin layers, supported Hoex in the research.
- Solar cell manufacturers OTB Solar license the thin layer deposition process by which the increased efficiency was achieved.

The twenty teens look to be the "solar decade." (click to enlarge)

QUOTES
- Eicke Weber, director, Fraunhofer Institute for Solar Energy Systems: "The Fraunhofer Institute for Solar Energy Systems has been highly successful over 25 years in developing technologies in the areas of renewable energy and energy efficiency, and transferring these innovations to industry…"
- PhysOrg: “Solar cells have for years looked like a highly promising way to partly solve the energy problem. The sun rises day after day, and solar cells can conveniently be installed on surfaces with no other useful purpose. Solar energy also offers opportunities for use in developing countries, many of which have high levels of sunshine.”