MITSUBISHI MAKES BETTER SOLAR CELL

Mitsubishi Electric Develops Practical Use Multi-Crystalline Silicon Solar Cell with World’s Highest Conversion Efficiency Rate of 18.0%
May 31, 2007 (Business Wire via Yahoo Finance)

WHO
Mitsubishi Electric Corporation, President/CEO Setsuhiro Shimomura; National Institute of Advanced Industrial Science And Technology (AIST);
soaring higher
WHAT
Mitsubishi has created a solar cell that converts 18% of sunlight hitting it into electricity.

WHEN
The new cell, its efficiency determined May 31, 2007, will be formally presented in December 2007. It will thereafter be mass produced.

WHERE
- Mitsubishi is based in Tokyo.
- The new cell will be formally presented at the Fukuoka 17th International Photovoltaic Science and Engineering Conference.

WHY
- The prototype cell was a 150 mm square multi-crystalline silicon wafer
- 18% was 1.2% greater than previous conversion.
- Efficiency determined by AIST, a public verification agency
- New conversion efficiency from (1) lower reflectivity surface texture on the multi-crystalline silicon and (2) “a process to print electrodes on the surface of the silicon (metallization) and reducing shade loss of front grid electrodes.”
- Result: Same surface area, 7% greater electric output; Application: smaller installations, narrow roofs.
a closer look (click to enlarge)
- Cell features:
1. Reactive Ion Etching (RIE) method: highly reactive ions from RF plasma etch target material, creating texturized surface on silicon, increasing absorbed light
2. New electrode material sustains crystalline performance
3. Improved surface qualities expands area of electrical output
4. Modified screens and front metal electrodes reduce “shading loss of front grid electrodes” 40%

QUOTES
“Mitsubishi Electric is committed to global environmental preservation and sustainable society through the spread of photovoltaic systems.”