Researchers at Michigan State University have created a
fully transparent solar concentrator, which could turn any window or sheet of
glass (like your smartphone’s screen) into a photovoltaic solar cell. Unlike
other “transparent” solar cells that we’ve 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 they cast a colorful shadow too.
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. [Research paper: DOI: 10.1002/adom.201400103-
"Near-Infrared Harvesting Transparent Luminescent Solar
Concentrators"]
If you look closely, you can see a couple of black strips
along the edges of plastic block. Otherwise, though, the active organic
material — and thus the bulk of the solar panel — is highly transparent. (Read: Solar singlet fission bends the laws of physics to boost solar power efficiency by 30%.)
Michigan’s 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 aren’t huge figures, but on a larger scale — every window in a house or
office block — the numbers quickly add up. Likewise, while we’re probably not
talking about a technology that can keep your smartphone or tablet running
indefinitely, replacing your device’s 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.
Source:extremetech.com Via:bloomingpost.com
