Palm-sized solar tiles that recycle artificial light can be used in curtains, window shades, and wallpaper

When you think about solar panels on a house, you picture
them on the roof. Considering the sun is outside in the sky, this makes sense. But
solar panels can also be placed in windows or on walls, and can even be put to
use while hiding indoors.  A team of
researchers at Virginia Tech is developing low-cost, flexible solar tiles that
can be incorporated into curtains and wallpaper to capture both natural and
artificial sunlight. 


Researcher Congcong Wu holds up one of the flexible artificial light-recycling tiles. Image source: Virginia Tech. 

Less than a millimeter thick, the new solar panels are
palm-sized and can generate about 75 mW of power. Made using a screen-printing
process that adheres a layer of titanium oxide paste into a thin, flexible
base, they’re scaled up in rolls to be used in curtains, window shades, and

One major benefit is that the technology is fairly cheap to
produce, and it’s manufactured at low temperatures, making the equipment to
fabricate the panels easy to operate. Better yet, the scalability of being able
to create the panels in sheet rolls means you could wallpaper your home in the
panels to run everything from your alarm system to recharging your devices —
you could even
use it to power your LED lights.

The most useful feature is likely the panels’ ability to
absorb diffused light. This means the range of light they can harvest extends
beyond sunlight, and into that thrown off by LED, incandescent, and fluorescent
lighting. Basically, the system could recycle the light from a building’s
internal fixtures to help power those same lights.

Currently the panels operate at about 10% efficiency, which
isn’t far off from the peak efficiency of 13 to 15% of amorphous silicon
panels. The team believes the efficiency can be increased to the point where
flexible panels outpace them, eventually making them viable to be woven into
clothing, such as military uniforms and backpacks.

Right now the researchers are on the edge, actively working
to integrate the product with the market while seeing a wide variety of uses
for the technology from clothing to windows, to smart buildings to UAVs, to
mobile charging stations.

research was originally published in the journals Solar Energy Materials and Solar Cells and ACS Energy Letters.