June 5, 2012


Cheap Dye-Sensitized Solar Cell Moves toward Commercialization (PETER FAIRLEY, 5/30/12, Technology Review)

Unlike thin-film and silicon panels, dye-based panels can be produced in cheap roll-to-roll processes akin to printing. So even if they are less efficient than silicon solar cells, they could prove cost-effective.

The Northwestern development is just the latest in a string of advances in what Michael McGehee, director of Stanford University's Center for Advanced Molecular Photovoltaics, recently dubbed a "renaissance" in dye-sensitized cells. Recent advances in the field could finally transform these elegant scientific curiosities into practical energy-generation devices. 

In a dye-sensitized solar cell, incoming light excites a porous layer of titania coated with a dye, generating negative and positive charges. The negative charges--excited electrons--flow out of the cell through the titania, while positive charges flow into a liquid electrolyte. As with electrolyte-filled alkaline batteries, leakage is an ever-present danger, especially in solar panels subject to extreme weathering. Electrolytes heated to 80° C (on a rooftop, for instance) can expand and rupture the panel's seal. The dye cells' iodine-based electrolyte is also corrosive enough to eat through even rust-resistant metals such as aluminum and stainless steel.

Northwestern University chemist Mercouri Kanatzidis, materials scientist Robert Chang, and two graduate students replaced the dye cells' liquid electrolyte with a solid iodine-based semiconductor. While prior solid-state designs have reduced the power output of dye cells, the Northwestern design actually boosts performance, the researchers say, because the cesium-tin-iodine semiconductor that replaces the liquid electrolyte also absorbs light. "Our material actually absorbs more light than the dye itself," says Kanatzidis.

Just another breakthrough....

Posted by at June 5, 2012 5:59 AM

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