How To Make a Solar Cell with Donuts and Tea
By Aaron Rowe EmailMarch 18, 2009 | 12:48:15 PMCategories: Chemistry,
Materials Science, Nanotechnology
DonutholesDonuts and tea are the main ingredients in a MacGyver-style
do-it-yourself solar cell, explained step-by-step in this video.
"It turns out these delicious little things contain everything we need
to make a simple solar cell," said Blake Farrow, a Canadian scientist
who filmed the video while visiting Prashant Kamat's lab at the
University of Notre Dame.
Powdered sugar contains titanium dioxide nanoparticles, a substance that
is also used in paint. When that powder is coated with an organic dye,
like the colorful chemicals in pasionfruit tea, it can be used as the
light-absorbing layer of a photovoltaic device.
"In dye-sensitized solar cells, colored materials like tea absorb some
visible light and transfer the energy to good electron transporting
materials, like white TiO2, that cannot absorb on their own," said Farrow.
Once those electrons have been excited, they need somewhere to go. So
Farrow sandwiched the TiO2 between a clear electrode, and a graphite
electrode that he fashioned by rubbing a pencil onto some glass. As a
finishing touch, he added some electrolyte solution, improvised from
everclear and iodine water purification tablets.
Dye-sensitized solar cells are cheaper and more durable than traditional
photovoltaics, but they are less efficient. And by extracting the
titanium dioxide from donuts, Farrow gives them a whole new layer of
inefficiency.
Go there... See Video
http://blog.wired.com/wiredscience/2009/03/donutsolar.html
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