Good News: Solar Cell Diversity Continues to Increase
Dye sensitized solar cells have been around for a while, not that many would have noticed. Dyesol, and Konarka are both blazing paths into new solar territory, but have had limited exposure. The typical solar cells we see on rooftops today are of the first generation silicon variety. In the news we hear about the second generation of solar cells that use exotic metals like copper indium gallium diselenide (CIGS), and achieve impressive results. We cheered when Nanosolar's first shipment went out last month, and we keep our ear to the ground for new technology on the horizon. So why are we excited about the new developments in dye sensitized solar cells?With the market for solar energy rapidly accelerating, production of solar cells has exploded. Before, it might have been O.K. if solar technology used expensive and energy intensive single crystal silicon as the substrate. It was probably O.K. to use toxic, or rare metals to prove the point that solar energy is possible. However, with the rapid rise in production these energy intensive, and toxic elements increasingly become a problem.
Shaik Zakeeruddin and Michael Grätzel (the dye sensitized solar cell is also known as a Grätzel cell), along with their colleagues have just solved one of the challenges facing the dye sensitized solar cell, opening the door for less-toxic production models, more form factors, and increased diversity of solar cell types.
The limitation with previous dye sensitized solar cells is they required a volatile organic solvent as the electrolyte. Zakeeruddin and Grätzel have found that a combination of two ionic liquids along with a novel highly conjugated ruthenium-based dye gave them a solvent free solar cell.
This new solar cell currently runs at about 7.6% efficiency, and is highly stable for thousands of hours even in high heat conditions. The new technology allows inexpensive manufacturing using common materials. The solar cell is less toxic with the ionic liquids, and the materials are now even more flexible (literally and figuratively) for product development. The dye sensitized solar cell is likely to become one of the most diverse types of solar cells, and hopefully we will see more of them soon.