Dye-sensitized solar cells have long been held up as a promising alternative to silicon.
Dye-sensitized solar cells, or DSSCs, use a number of cost-effective, readily abundant materials for their base — from plastic to ceramics to metal or glass. They generate electricity due to an interaction between light and a cheap pigment painted on titanium dioxide. They have the potential to generate electricity at low levels of light, for example in partial shade or on cloudy days. And they have been shown to reach efficiencies not too far off from their mainstream silicon counterparts.
Until now, however, these cells have been held up by concerns about chemical stability in adverse weather conditions. Here's how the Wikipedia entry on dye-sensitized solar cells describes the problem:
The major disadvantage to the DSSC design is the use of the liquid electrolyte, which has temperature stability problems. At low temperatures the electrolyte can freeze, ending power production and potentially leading to physical damage. Higher temperatures cause the liquid to expand, making sealing the panels a serious problem.
“Organic material in DSSCs tends to degrade, so we looked to nature to solve the problem,” Velev said. “We considered how the branched network in a leaf maintains water and nutrient levels throughout the leaf. Our microchannel solar cell design works in a similar way. Photovoltaic cells rendered ineffective by high intensities of ultraviolet rays were regenerated by pumping fresh dye into the channels while cycling the exhausted dye out of the cell. This process restores the device’s effectiveness in producing electricity over multiple cycles.”
As Michael Grätzel, inventor of the DSSC, explains in this video, the whole concept of a DSSC is based on mimicking the natural, molecular process of photosynthesis in a leaf.
Making sure that these cells can maintain their capacity over a longer period of time may well be a huge leap forward for this promising technology.
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