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How Solar-powered Sunglasses Work


Advances in Solar Cells

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Sun exposure becomes less of an issue when you think about applying thin-film photovoltaic devices to places such as windows, skylights and even a building façade to make its exterior photovoltaicly active.

­While conventional solar panels, made from silicon cells, continue to have an advantage over this new solar technology, they remain inflexible, expensive and compared to the newest innovations, no longer the most efficient option. Dye-sensitized solar cells (DSCs) have a few other tricks up their sleeve. They are able to work as efficiently at 149 degrees F (65 degrees C) as at 77 degrees F (25 degrees C), whereas silicon cells lose 20 percent of their energy efficiency at extreme temperatures.

And because of the wafer-thin and flexible properties, DSC technology can be applied in ways never considered for conventional cells. Militaries, for instance, have become interested in Grätzel cells. New tents and fabrics are able to provide up to 1 kilowatt of energy (enough to power a few lights and a laptop) [source: Tent Manufacturers Marketplace]. And on a larger scale, flexible solar panels used to cover tents power sophisticated equipment. Additionally, Grätzel cells could be engineered into wearable photovoltaic cells. Lightweight wearable solar panels could power and recharge all electrical devices soldiers or Marines carry, eliminating the need for extra battery packs or bagfuls of batteries in the field.

­While DSC technology has new groundbreaking applications, research into other areas of solar energy shows promise in plastic solar cells -- an idea where layers of titanium oxide are chemically modified -- that could have energy efficiency levels greater than those seen in Grätzel cells. Maybe one day not only will the lenses be photovoltaic, but the entire pair of sunglasses will be an energy source.