Part One of Three:
Coating the Glass Plates
Edit
1
Obtain 2 equal-sized
glass plates. Plates of
the size used as covers
for microscope slides
would be ideal.
2
Clean both surfaces of
the plates with
alcohol. Once the plates
are cleaned, handle them
only by the edges.
3
Test the plate faces
for conductivity. Do
this by touching the
surfaces with the leads
from a multimeter. Once
you have established
which side of each plate is
the conductive side, place
them side by side, one
plate conductive side up
and the other conductive
side down.
4
Apply transparent
tape to the plates. This
will hold the plates in place
for the next step.
Place the tape along
either of the long side
of the plates to overlap
1 millimeter (1/25 inch)
of the edges.
Place tape over the
outer 4 to 5 millimeters
(1/5 inch) of the
conductive side up
plate.
5
Apply a solution of
titanium dioxide to
the plates. Put 2 drops
on the conductive side up
plate, then spread it
evenly over the plate
surface. Allow the titanium
dioxide to cover the
conductive-side-down
plate.
Before applying the
titanium dioxide
solution, you may first
want to coat the plates
with tin oxide.
6
Remove the tape and
separate the plates.
Now you'll treat the 2
plates differently.
Place the conductive-
side-up plate on an
electric hot plate
overnight to bake the
titanium dioxide onto
the plate.
Clean the titanium
dioxide off the
conductive-side-down
plate and place it where
it won't collect dirt.
7
Prepare a shallow
dish filled with dye.
The dye can be made from
raspberry, blackberry or
pomegranate juice or by
brewing a tea from red
hibiscus petals.
8
Soak the titanium-
dioxide-coated plate,
coated side down, in
the dye for 10
minutes.
9
Clean the other plate
with alcohol. Do this
while the titanium dioxide-
coated plate is soaking.
10
Retest the cleaned
plate to find its
conductive side. Mark
the side that doesn't
conduct with a plus sign
(+).
11
Apply a thin carbon
coating to the
conductive side of the
cleaned plate. You can
do this by going over the
conductive side with a
pencil or by applying a
graphite lubricant. Cover
the entire surface.
12
Take the titanium-
dioxide-coated plate
out of the dye. Rinse it
twice, first with de-ionized
water and then with
alcohol. Blot dry after
rinsing with a clean tissue.
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Part Two of Three:
Assembling the Solar
Cell
Edit
1
Place the carbon-
coated plate onto the
titanium-dioxide plate
so the coatings touch.
The plates should be
slightly offset, about 5
millimeters (1/5 inch). Use
binder clips on the long
edges to hold them in
place.
2
Apply 2 drops of an
iodide solution to the
exposed coating. Let
the solution soak through
the plate coatings so
they're covered
completely. You may want
to open the binder clips
and gently lift 1 of the
plates up to allow the
solution to spread over
the entire surface.
The iodide solution will
enable electrons to flow
from the titanium-
dioxide-coated plate to
the carbon-coated
plate when the cell is
exposed to a light
source. Such a solution
is called an electrolyte.
3
Wipe excess solution
off the exposed
portions of the plates.
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Part Three of Three:
Activating and Testing
the Solar Cell
Edit
1
Attach an alligator
clip to the exposed
coated sections on
either side of the
solar cell.
2
Connect the black
wire of the
multimeter to the clip
connected to the
exposed titanium
dioxide coating. This
plate is the solar cell's
negative electrode, or
cathode.
3
Connect the red wire
of the multimeter to
the clip connected to
the exposed carbon
coating. This plate is the
solar cell's positive
electrode, or anode. (In a
previous step, you
marked it with a plus sign
on its non-conductive
side.)
4
Place the solar cell
next to a light source,
with the negative
electrode facing the
source. In a school
classroom, this can be
done by laying the cell on
top of the lens of an
overhead projector. In a
home setting, another light
source, such as a
spotlight or the sun itself,
can be substituted.
5
Measure the current
and voltage
generated by the
solar cell with the
multimeter. Do this both
before and after the cell is
exposed to light.b