"Cycles of energy and materials have existed on the Earth
for billions of years. In a few hundred years, we have come
to dominate and control many of these cycles. Our search for
artificial photosynthesis is, therefore, not merely to present
ourselves with alternatives for powering our society, but
it is a search for our place in the Earth's biosphere."
-Dr. Greg Smestad (Inventor of the kit)
Step 1 - Stain the Titanium Dioxide with the Natural Dye:
Stain the white side of a glass plate which has been coated
with titanium dioxide (TiO).
This glass has been previously coated with a transparent conductive
layer (SnO),
as well as a porous TiO
film. Crush fresh (or frozen) blackberries, raspberries, pomegranate
seeds, or red Hibiscus tea in a tablespoon of water. Soak
the film for 5 minutes in this liquid to stain the film to
a deep red-purple color. If both sides of the film are not
uniformly stained, then put it back in the juice for 5 more
minutes. Wash the film in ethanol and gently blot it dry with
a tissue.
Step 2 - Coat the Counter Electrode: The solar cell
needs both a positive and a negative plate to function. The
positive electrode is called the counter electrode and is
created from a "conductive" SnO
coated glass plate. A Volt - Ohm meter can be used to check
which side of the glass is conductive. When scratched with
a finger nail, it is the rough side. The "non-conductive"
side is marked with a "+." Use a pencil lead to
apply a thin graphite (catalytic carbon) layer to the conductive
side of plate's surface.
Steps 3 & 4 - Add the Electrolyte and Assemble the
Finished Solar Cell: The Iodide solution serves as the
electrolyte in the solar cell to complete the circuit and
regenerate the dye. Place the stained plate on the table so
that the film side is up and place one or two drops of the
iodide/iodine electrolyte solution on the stained portion
of the film. Then place the counter electrode on top of the
stained film so that the conductive side of the counter electrode
is on top of the film. Offset the glass plates so that the
edges of each plate are exposed. These will serve as the contact
points for the negative and positive electrodes so that you
can extract electricity and test your cell.
|
Use the two clips to hold the two
electrodes together at the corner of the plates.
The output is approximately 0.43 V and 1 mA/cm2
when the cell is illuminated in full sun through the
TiO
side.
|
|
|