I’m writing to you from Belgium-based IMEC, an independent research center that bridges the gap between fundamental university research and technology development in industry. I came to learn more about solar cells and how PCB manufacturing and assembly knowledge might transfer to other areas, expanding our market in interesting ways.
The recently reported 40% annual growth rate in photovoltaics (PV) is enough to draw attention to that market. I talked to Paul Heremans, department director of nano-engineered component science and technology at IMEC. At IMOMEC, an associated lab located on the Hasselt University campus, IMEC is working on a reproducible process for high-efficiency organic solar cells using Plextronics’ Plexicore materials and inks. According to Heremans, the method to stabilize the nanomorphology of organic solar cells results in a lifetime improvement of at least a factor of 10. By creating stabilized solar cells, this breakthrough paves the way to commercial organic solar cells with an operational lifetime of more than five years and efficiencies of more than 10%, IMEC’s present goal.
However, the efficiency and operation of organic solar cells depends on the nanomorphology of the active layer. A stable mix of organic compounds in the active layer that can trap the light’s energy and transport it to an electric contact is a large boost towards a robust organic-based cell that can be mass manufactured. IMEC/IMOMEC’s latest method and new conjugated polymers for stabilizing the active layer have shown no degradation of efficiency after more than 100 hours. The cells achieved efficiencies near 4%, state-of-the-art for this type of cell. IMEC is driving for organic multi-junction solar cells with an efficiency of 10% by 2012.
“Right now, it’s all about finding better materials and combinations of materials, not to mention industry partners for making the most robust solar product,” adds Heremans.
IMEC started working on solar cells in 1984 with crystalline silicon (Si) as the backbone of its photovoltaic activities. Crystalline Si solar cells still command 90% of the solar market. And although other options also are important, R&D on crystalline Si solar cells forms a fundamental part of IMEC’s photovoltaic research. This type of cell uses techniques that are closer to front-end electronics manufacturing: doping, metallization, wafer thinning, and thin-film processing. Fabs, not EMS manufacturers, have a firm grip on these processes. But the organic materials side of things, using and printing inks, would seem a natural technology transfer for our PCB board-assembly process, once the process stabilizes.
Now, as I ponder this information during the long trip home from Belgium, I can’t help but think of the creative things that EMS providers already do that are just amazing. Many have taken on test and programming previously done by the OEM customer. Others now can go into the stacking of package-on-package (PoP) devices. Many handle final box builds on-site. And the medical side of board build goes way beyond flexible circuits and cleanroom manufacturing. What’s one more challenge to our industry? Just one more mountain to climb.
Gail Flower, editor-in-chief