First invented in the Bronze Age, 5,000 years or so ago, glass is such an integral part of modern life that we rarely give much thought as to how it performs or is produced. Today, though, the development of novel forms of glass promises to bring high-tech, low-cost advances to a range of applications, including solar power.
Glass has many advantageous qualities and one major disadvantage: it’s brittle. It shatters on impact. We long ago mastered the art of molding glass into many different curves and fantastical shapes, but once it’s set, it’s set until you take a hammer to it.
That is changing, as researchers at McGill University in Montreal have adapted structural characteristics from the shells of mollusks to give glass new resilience and flexibility. The scientists found that the extremely tough and bendable nacre, or mother-of-pearl, that coats the inner shells of the creatures is made up not of an unbroken surface, but of millions of microscopic components or “tablets.” When the shell is bent or deformed, the cracks between the tablets allow it to bend, yet remain intact. Think of blocks of sea ice floating on a moving water surface; they rise and fall and compress and spread, but the overall surface of the ice remains the same.
Fractured Yet Flexible
In the same way, the McGill researchers found that they can pre-crack glass with lasers to create a puzzle-piece design. The resultant microfractures are filled with polyurethane, creating a material that is weak at the boundaries of the tiny fragments, but resilient as a whole. Flexible glass.
The immediate applications envisioned include less breakable smartphones, for instance. But advances in making glass more flexible, resilient, and versatile will likely have implications for solar power, as well.
When a technology is as commoditized as solar panels, with prices halving in just the last few years, the tendency is to think that innovation in the materials has reached an apex; the only further development needed is to squeeze more cost out of the manufacturing process. Solar panels with next-generation glass, however, could help drive the Murphy’s Law process of price reductions in solar technology while also producing panels with a wider range of possible applications. Crystalline silicon solar modules, which require the rigid protection provided by glass, are more efficient than amorphous silicon modules. Amorphous silicon (often used in thin-film solar coatings) has the benefit, however, of being flexible, making it applicable in a host of environments where conventional glass is less robust.
Spray On, Not Tan
Developed at the University of South Florida in alliance with the National Renewable Energy Laboratory and being commercialized under the mark SolarWindow by New Energy Technologies, a new glass with tiny transparent solar cells integrated is due to reach the market this year. New Energy produces both flat glass for windows and structural glass walls and curtains for tall structures that have all the usual qualities of glass and also act as solar panels. Made of organic polymers (thus grown, not manufactured), the transparent solar cells are the world’s smallest, the company says, measuring less than one-fourth the size of a grain of rice. They are sprayed onto the glass in a novel process that does not require the high temperatures and vacuum chambers of other spray-on solar technologies.
Meanwhile, building off of NASA’s R&D on solar panels for deep space satellites, Entech Solar has developed a concentrating solar system called SolarVolt that uses tiny versions of Fresnel lenses – originally developed in the 19th century to focus the beams of lighthouses for many miles out to sea. The miniature photovoltaic array has achieved a 20X concentration of the sun’s rays, enabling much smaller-sized systems per unit of energy captured.
These advances in the structure of glass, a 5-millenium-old invention, could help accelerate the solar revolution and bring closer the day when renewable energy is less expensive, by any measure, than fossil fuels.
Tags: Renewable Energy, Research & Development, Science & Technology, Smart Energy Program, Solar Power
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