Transparent Coloured Solar Cells
Transparent Coloured Solar Cells
Imagine a stained glass window in
your home that could power your lighting or charge your phone and other
devices. That’s the vision of researchers at University of Michigan, who
have developed the first semi transparent coloured solar cells. They
hope that their invention can go on to be incorporated into the windows of a
building, or even billboards and adverts. The cells can be made to any colour
and are produced on an ultra thin film.
Solar cells are generally black, as
this allows maximum absorption of energy from the suns rays. Whilst these semi
transparent tinted photovoltaics only produce a third of the normal black solar
panels, they do have a much wider range of possible uses and locations for
mounting. The semi transparent colours can open up a load of new possibilities
for designers. The sacrifice in efficiency is made up by the increased range of
uses.
“Today, solar panels are black
and the only place you can put them on a building is the rooftop. And the
rooftop of a typical high-rise is so tiny,” said Jay Guo, a professor
of electrical engineering and computer science at the university. ”We
think we can make solar panels more beautiful—any color a designer wants.”
The team have demonstrated the idea
with a palm sized American flag. ”All the red stripes, the blue background
and so on—they are all working solar cells,” Guo said. The flag operates at
2% overall efficiency which results in an identical meter-square flag
having the ability to power small devices and fluorescent light bulbs. The team
are currently working to improve this figure and home in on the 10%
efficiency found in state of the art cells (that are not coloured).
To make the cells, an ultrathin
sheet of amorphous silicon is sandwiched between two semi-transparent
electrodes, which allow the light to hit the semiconductor, as well as carrying
the electrical current generated by the cell. ”This hybrid structure, a
combination of both organic and inorganic components, lets the researchers make
cells that are 10 times thinner than traditional amorphous silicon solar cells,”
said the university.
To get an idea of the thinness of
the cells, the thickness is adjusted to produce different colours - 6
nanometers thick for blue, 31 nanometers thick for red, and so on.
The varying thickness of the cells reflect different wavelengths of light, and
thus, the colour is not produced by dyes or a coloured film that would lower
efficiency further.
Another feature worth mentioning is
that results have shown that these cells would not operate better or worse
based on the suns location as the colour hues do not change with viewing angle.
Traditional solar cells however work better when in direct sunlight and thus
have to pivot with the location of the sun.
No comments:
Post a Comment