Researchers at Michigan State University have created a fully transparent solar concentrator, which could turn any window or sheet of glass (like your smartphones screen) into a photovoltaic solar cell.
Unlike other transparent solar cells that weve reported on in the past, this one really is transparent, as you can see in the photos throughout this story. According to Richard Lunt, who led the research, the team are confident that the transparent solar panels can be efficiently deployed in a wide range of settings, from tall buildings with lots of windows or any kind of mobile device that demands high aesthetic quality like a phone or e-reader.
Scientifically, a transparent solar panel is something of an oxymoron. Solar cells, specifically the photovoltaic kind, make energy by absorbing photons (sunlight) and converting them into electrons (electricity). If a material is transparent, however, by definition it means that all of the light passes through the medium to strike the back of your eye. This is why previous transparent solar cells have actually only been partially transparent and, to add insult to injury, they usually cast a colorful shadow too.
The organic salts absorb UV and infrared, and emit infrared processes that occur outside of the visible spectrum, so that it appears transparent.
To get around this limitation, the Michigan State researchers use a slightly different technique for gathering sunlight. Instead of trying to create a transparent photovoltaic cell (which is nigh impossible), they use a transparent luminescent solar concentrator (TLSC). The TLSC consists of organic salts that absorb specific non-visible wavelengths of ultraviolet and infrared light, which they then luminesce (glow) as another wavelength of infrared light (also non-visible). This emitted infrared light is guided to the edge of plastic, where thin strips of conventional photovoltaic solar cell convert it into electricity.
Michigans TLSC currently has an efficiency of around 1%, but they think 5% should be possible. Non-transparent luminescent concentrators (which bathe the room in colorful light) max out at around 7%. On their own these arent huge figures, but on a larger scale every window in a house or office block the numbers quickly add up. Likewise, while were probably not talking about a technology that can keep your smartphone or tablet running indefinitely, replacing your devices display with a TLSC could net you a few more minutes or hours of usage on a single battery charge.
The researchers are confident that the technology can be scaled all the way from large industrial and commercial applications, down to consumer devices, while remaining affordable. So far, one of the larger barriers to large-scale adoption of solar power is the intrusive and ugly nature of solar panels obviously, if we can produce large amounts of solar power from sheets of glass and plastic that look like normal sheets of glass and plastic, then that would be big.
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