This article was taken from the March issue of Wired UK
magazine. Be the first to read Wired's articles in print before
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Solar power could be the future, but it'll be a while until
panels are on every roof. Fear not: while working at the University
of Notre Dame, Indiana, engineer Blake Farrow showed you don't need
the far corners of the periodic table to put together a solar cell.
Just grab some tea-time staples.
1. Treat yourself to some powdered
doughnuts and herbal tea. The powdered sugar on US-style doughnuts
contains titanium dioxide (TiO2 or E171). This is a semiconductor
that can be used to make solar cells. To extract the TiO2 in a
useful form, first scrape off all the powder and put it in a cup of
warm water. Stirring this will dissolve all the sugar (there is a
lot of it).
2. Running the whitish water through a
coffee filter will leave behind a white blob -- this is the
precious TiO2, along with some unwanted fat.
3. Because the fat is useless for solar
cells, you'll need to put the residue in a hot oven for a few hours
to vaporise it. The TiO2 remains as nanoparticles, each around
4. Throw these particles into high-proof
ethanol (vodka will do: use 1ml per doughnut) and shake.
5. Now conductive glass is needed (tough
to find, but indium-doped tin oxide is best). With an eye dropper
or syringe, drop ten layers of the nanoparticle spirit on the
glass, allowing it to dry with each layer. Then put it back in the
6. This is now a solar cell, but it will
work only with UV light (the bad kind). Here is where the tea comes
in. Leave the nanoparticle solar cell sitting in a cup of hibiscus
tea for a couple hours, and soon it will have absorbed the colour,
shifting its useful range from UV (useless) to visible light.
7. To collect energy from this solar
cell, you'll need a counter-electrode. Take another piece of
conducting glass and use a dark pencil to cover the surface with
8. To get your electricity to your
counter-electrode, a generous amount of iodine in high-proof
alcohol works well as an electrolyte. Use one part alcohol to three
parts Lugol's solution -- available from health stores and aquarium
9. Cut a hole in some thin plastic or tape to
use as a spacer, and place it on the nanoparticle cell. Drop some
electrolyte on top, and quickly sandwich the two electrodes
together with some bulldog clips.
10. You're done! A multimeter connected to both
of the conducting electrodes should show about half a volt when in
the sun. See a tutorial at YouTube.