Step 1.
Cut a piece sheet copper into the size and
shape you wish for your cell. Although .025 inch thick copper
was used for the cells described here, just about any thickness
will do.
Copper is a soft metal and can be cut with tin snips or even
with an old pair of scissors.
Cut your cell with a diameter of 1 1/2 inches, we strart with a
smaller cell because it is much easier to work with. The larger
the heat source the bigger the size copper you can use to create
your solar cell. After you get the hang of it you can then build
larger cells..
As you cut the copper, be sure to leave a "handle" so that you
may grip the cell with pliers without marring the cell's active
surface.
step 2
The surface of the cell
must be made extremely
clean. Prepare
a solution of nitric acid
by carefully mixing 20
parts nitric acid and 80
parts distilled water.
Remember towear protective
goggles or other
suitable eye protection
and to work in a well
ventilated area whenever
you work with
chemicals.
IMPORTANT! ALWAYS ADD ACID TO WATER!
NEVER ADD WATER TO ACID!
Begin by carefully polishing the face of the cell with a fine
grade of steel wool until it shines brightly. Then place the cell
with the shiny side up, in the solution of nitric acid.
Soon, tiny bubbles will form on the copper disk. Stir the
solution occasionally. When the disk seems shiny and well
cleaned, remove and rinse it under cool running water.
WARNING! Never to allow your skin to touch the acid, and
that no acid remains on the cell.
The cell will sometimes work without the acid cleaning if it is
simply well polished by the steel wool. However, we strongly
recommend the acid cleaning.
Nitric acid and the other chemicals mentioned in the text can
be easily ordered from a number of mail-order chemical houses
such as found in the classified section of magazines such as
Popular Science.
Step 3.
Cuprous oxide is now formed on the disk by heating
it over a Bunsen burner, or propane torch. A gas stove can be
used, but results may be unpredictable.
The time me disk must be heated varies greatly depending on
the heat of the torch, and the thickness and size of the copper
piece. Using a standard propane torch from the hardware store
and a disk of the described size, I found 2 minutes and 40 seconds
to be ideal. If you heat it too long, you run the risk of burning off
the oxides. Heating for too short a time may prevent the oxides
from forming fully.
Photo sensitive oxides are formed by heating the disk for several minutes.
The Copper is heated on one side only, until it is glowing and red hot!
copper must be kept at an even red hot,all over it's surface for about
2 minutes and 45 seconds by moving the copper over the tourch in a
round motion. counter clock wise. The side of the cell that is not exposed
to the flame will become coated with the black cupric oxide.
Now just beneath this black oxide is the photo sensitive red cuprouse oxide.
This red cuprouse oxide can be purchsed in powder form and mixed with a
special solvent, which is clear, and is described in the Japan Patent. The
Oxide can then be screen printed onto the copper surface. This oxide
material is different than the chemicals used in the Patent.
After heating your cell for the prescribed time, it must be carefully cooled.
There are two ways to go about this. You can cool the copper quickly by
either placing it face down on a flat metal surface, or by waiting a few moments
and then quenching it in cool water. The advantage to cooling the cell
quickly is that the unwanted black cupric oxide will often flake off the cell
due to the difference in contraction rates of the oxides. Unfortunately, I have
had bad luck with this method despite extensive experimentation with different
temperatures and procedures.
What has worked very well for me is to bring the cell's temperature down
as slowly as possible making sure the black oxide does not crack at all. Once
completely cool, the cell is immersed in the nitric acid bath. You must wait
while the acid begins to dissolve the black oxide. Then you remove and rinse
the cell.
A very weak solution of sodium cyanide can also be used with good results.
However, you should be extremely careful when using it. Cyanide is an extremely
poisonous chemical, and if accidentally mixed with an acid can create
deadly fumes. At this point the black oxide covering the cell can be rubbed
away with steel wool and a little elbow grease. After all of the Black oxide has
been removed, your cell should have a uniform caoting of deep red on one side.
black oxide has been removed, your cell should have a uniform coating of deep red on one side. Don't worry if the very outside
edges of your cell don't have the coating, this is due to uneven cooling and is normal. Keep in mind that the red coating must not
be scratched or scraped away to reveal the bare copper plate beneath. If this happens the cell might short in the final step and not
work at all.
Testing:
There are now several ways that you can test you solar cell even though it is not finished, it can generate power.
If you are building the cell for a science fair or other demonstration, you may want to stop and use the cell at this point while the
cuprous oxide is still visible. If you hold the cell near a source of bright light, a current will be generated between the cuprous oxide
coating and the copper plate. The copper will form the positive terminal and the cuprous oxide the negative.
Making contact with the copper portion of the disk is very easy. Simply sand a small bare spot on the back of the solar cell and attach
a wire. Attaching the wire and making a good contact with the cuprous oxide is more difficult, it is hard to solder and attach anything.
but it can be done by pressure gluing or other.
method of making a good contact with this large of a surface area, is by attaching a wire grid to it. A better way is to apply a very thin
layer of silver or gold called a transparent An easily fabricated but temporary transparent electrode can be made from salt water. Or as seen
in our Chlorine cells and a container glued to the cell and the liquid applied. A soloution of salt or acid will conduct electricity and also pass
light to the cell. Drip a small amount of salt water or your spit, on to the center of the cell. Make sure that the water rests only on the
cuprous oxide and does not touch any of the solar cell's copper surface or it will short out and will not produce any free electrical energy at
all.
Now, attach one wire from a galvanometer, digital voltmeter using the milliamp or low voltage setting to some exposed portion of the
cell's copper surface. Usually the back or the edges have some exposed copper. Touch the other meter lead to the surface of the water. The
meter will spring to life. Next, bring a bright source of light such as a 100 watt bulb near the cell. The meter should show a slightly smaller
voltage as the light approaches. Your cell will produce best in sunlight! The cell is changing some of the light into electricity but is having to
counteract the current generated by the saltwater, hence the drop in voltage. The salt water actually acts as an electrolyte and with the oxide
generates its own current just as a small battery would. Another way that you can test your cell is by making a wire electrode for the surface.
This is done simply by coiling some 30 gauge silver-plated wire or aluminum wire and by holding it against the ( cells ) cuprous oxide
surface with a sheet of glass. A good way is to coil the wire around is to use a cone shaped dowel or other
object first in order to make good even spirals. Make sure that the wire touches the cuprous oxide only, and none of the bare
copper. You will always have some bare copper around the edges of the cell, so it is best to paint with enamel paint, let dry and then work
with the cell.
By simply attaching one wire of your meter to the silver wire, and one to the cell's exposed copper, you will be able to register a small
current when a light is brought near. In this form, the cell can be operated indefinitely and makes an excellent Science Fair Display.
Final Step:
Making The Silvering Solution: The final step in making your own solar cell will be to make a permanent transparent electrode. When
properly applied, this will give your cell a beautiful semi-mirrored finish and allow you to make electrical contact with the whole cuprous
oxide face of the cell. This step is probably the trickiest in the production of the cell.
But, just as with the last steps, it becomes somewhat easier with practice. Using distilled water, make ten percent solutions each of ammonia
water, potassium hydroxide and potassium sodium tartrate in seperate test tubes. A ten percent solution can be created by mixing 10 parts by
weight of solute in 90 parts of water. Please remember that the test tubes can become warm or even hot when the water is first added, so be sure to use Pyrex
glass test tubes. Also, make certain you have ample ventilation when mixing the ammonia solution. Dissolve in 1 oz. water a single crystal of silver nitrate. The
crystal should be somewhat larger than the head of a match. Begin adding drops of the ammonia solution to the dissolved silver nitrate until the water first
becomes brown, and then just begins to clear. Add a drop of potassium hydroxide to this solution. Then again begin adding drops of ammonia water until the
solution just begins to clear. The solution will remain somewhat cloudy. Too much ammonia in the solution can dissolve the cuprous oxide coating and can
damage or ruin the cell. Stir the mixture while adding a single drop of the potassium sodium tartrate solution. The mixture is now ready and should be used
immediately.
Applying The Solution :
Temperature and variations in the chemical mixture can
dramatically change the time required to complete the silvering
process. The best way to complete this step is by simple visual
examination of the process as it proceeds.
With the cell on a flat surface, begin by carefully pouring the
silvering mixture on to the center of the cell. Remember to avoid
letting this mixture contact any exposed copper. A good trick is to cover with paint or lacquer any exposed copper surfaces on the face of the cell. Continue pouring until the liquid has covered as much of the
surface as you can . If all the exposed copper on the surface has
been properly protected with the lacquer, you can actually pour the solution until it comes right to the edge. Since water has an affinity for itself
called "cohesion", it won't spill over the edge. Very soon, a thin film of silver will begin to form over the cell's surface. The liquid should be
poured off when the red oxide is still slightly visible beneath the silver. allow the silvering process to go a little too long rather than not
long enough since some of the silver coating can be polished away.You should now have a smooth silver coating through which
the red oxide is barely visible.
Completing the Cell contact can now be made to the cuprous oxide face of the ell by means of a ring of lead or silver-coated wire which is
slightly smaller in diameter than the disk itself. With the ring held firmly against the disk, a protective coating of thin lacquer
can be applied. Make certain the lacquer does not come between the wire and the disk. With wires attached to the disk's copper back and the
lead or silver ring, the cell is complete. The disk can now be housed behind glass, mounted to a sheet of plastic, cast in a clear resin or
housed in any other enclosure you desire!
must be made extremely
clean. Prepare
a solution of nitric acid
by carefully mixing 20
parts nitric acid and 80
parts distilled water.
Remember towear protective
goggles or other
suitable eye protection
and to work in a well
ventilated area whenever
you work with
chemicals.
IMPORTANT! ALWAYS ADD ACID TO WATER!
NEVER ADD WATER TO ACID!
Begin by carefully polishing the face of the cell with a fine
grade of steel wool until it shines brightly. Then place the cell
with the shiny side up, in the solution of nitric acid.
Soon, tiny bubbles will form on the copper disk. Stir the
solution occasionally. When the disk seems shiny and well
cleaned, remove and rinse it under cool running water.
WARNING! Never to allow your skin to touch the acid, and
that no acid remains on the cell.
The cell will sometimes work without the acid cleaning if it is
simply well polished by the steel wool. However, we strongly
recommend the acid cleaning.
Nitric acid and the other chemicals mentioned in the text can
be easily ordered from a number of mail-order chemical houses
such as found in the classified section of magazines such as
Popular Science.
Step 3.
Cuprous oxide is now formed on the disk by heating
it over a Bunsen burner, or propane torch. A gas stove can be
used, but results may be unpredictable.
The time me disk must be heated varies greatly depending on
the heat of the torch, and the thickness and size of the copper
piece. Using a standard propane torch from the hardware store
and a disk of the described size, I found 2 minutes and 40 seconds
to be ideal. If you heat it too long, you run the risk of burning off
the oxides. Heating for too short a time may prevent the oxides
from forming fully.
Photo sensitive oxides are formed by heating the disk for several minutes.
The Copper is heated on one side only, until it is glowing and red hot!
copper must be kept at an even red hot,all over it's surface for about
2 minutes and 45 seconds by moving the copper over the tourch in a
round motion. counter clock wise. The side of the cell that is not exposed
to the flame will become coated with the black cupric oxide.
Now just beneath this black oxide is the photo sensitive red cuprouse oxide.
This red cuprouse oxide can be purchsed in powder form and mixed with a
special solvent, which is clear, and is described in the Japan Patent. The
Oxide can then be screen printed onto the copper surface. This oxide
material is different than the chemicals used in the Patent.
After heating your cell for the prescribed time, it must be carefully cooled.
There are two ways to go about this. You can cool the copper quickly by
either placing it face down on a flat metal surface, or by waiting a few moments
and then quenching it in cool water. The advantage to cooling the cell
quickly is that the unwanted black cupric oxide will often flake off the cell
due to the difference in contraction rates of the oxides. Unfortunately, I have
had bad luck with this method despite extensive experimentation with different
temperatures and procedures.
What has worked very well for me is to bring the cell's temperature down
as slowly as possible making sure the black oxide does not crack at all. Once
completely cool, the cell is immersed in the nitric acid bath. You must wait
while the acid begins to dissolve the black oxide. Then you remove and rinse
the cell.
A very weak solution of sodium cyanide can also be used with good results.
However, you should be extremely careful when using it. Cyanide is an extremely
poisonous chemical, and if accidentally mixed with an acid can create
deadly fumes. At this point the black oxide covering the cell can be rubbed
away with steel wool and a little elbow grease. After all of the Black oxide has
been removed, your cell should have a uniform caoting of deep red on one side.
black oxide has been removed, your cell should have a uniform coating of deep red on one side. Don't worry if the very outside
edges of your cell don't have the coating, this is due to uneven cooling and is normal. Keep in mind that the red coating must not
be scratched or scraped away to reveal the bare copper plate beneath. If this happens the cell might short in the final step and not
work at all.
Testing:
There are now several ways that you can test you solar cell even though it is not finished, it can generate power.
If you are building the cell for a science fair or other demonstration, you may want to stop and use the cell at this point while the
cuprous oxide is still visible. If you hold the cell near a source of bright light, a current will be generated between the cuprous oxide
coating and the copper plate. The copper will form the positive terminal and the cuprous oxide the negative.
Making contact with the copper portion of the disk is very easy. Simply sand a small bare spot on the back of the solar cell and attach
a wire. Attaching the wire and making a good contact with the cuprous oxide is more difficult, it is hard to solder and attach anything.
but it can be done by pressure gluing or other.
method of making a good contact with this large of a surface area, is by attaching a wire grid to it. A better way is to apply a very thin
layer of silver or gold called a transparent An easily fabricated but temporary transparent electrode can be made from salt water. Or as seen
in our Chlorine cells and a container glued to the cell and the liquid applied. A soloution of salt or acid will conduct electricity and also pass
light to the cell. Drip a small amount of salt water or your spit, on to the center of the cell. Make sure that the water rests only on the
cuprous oxide and does not touch any of the solar cell's copper surface or it will short out and will not produce any free electrical energy at
all.
Now, attach one wire from a galvanometer, digital voltmeter using the milliamp or low voltage setting to some exposed portion of the
cell's copper surface. Usually the back or the edges have some exposed copper. Touch the other meter lead to the surface of the water. The
meter will spring to life. Next, bring a bright source of light such as a 100 watt bulb near the cell. The meter should show a slightly smaller
voltage as the light approaches. Your cell will produce best in sunlight! The cell is changing some of the light into electricity but is having to
counteract the current generated by the saltwater, hence the drop in voltage. The salt water actually acts as an electrolyte and with the oxide
generates its own current just as a small battery would. Another way that you can test your cell is by making a wire electrode for the surface.
This is done simply by coiling some 30 gauge silver-plated wire or aluminum wire and by holding it against the ( cells ) cuprous oxide
surface with a sheet of glass. A good way is to coil the wire around is to use a cone shaped dowel or other
object first in order to make good even spirals. Make sure that the wire touches the cuprous oxide only, and none of the bare
copper. You will always have some bare copper around the edges of the cell, so it is best to paint with enamel paint, let dry and then work
with the cell.
By simply attaching one wire of your meter to the silver wire, and one to the cell's exposed copper, you will be able to register a small
current when a light is brought near. In this form, the cell can be operated indefinitely and makes an excellent Science Fair Display.
Final Step:
Making The Silvering Solution: The final step in making your own solar cell will be to make a permanent transparent electrode. When
properly applied, this will give your cell a beautiful semi-mirrored finish and allow you to make electrical contact with the whole cuprous
oxide face of the cell. This step is probably the trickiest in the production of the cell.
But, just as with the last steps, it becomes somewhat easier with practice. Using distilled water, make ten percent solutions each of ammonia
water, potassium hydroxide and potassium sodium tartrate in seperate test tubes. A ten percent solution can be created by mixing 10 parts by
weight of solute in 90 parts of water. Please remember that the test tubes can become warm or even hot when the water is first added, so be sure to use Pyrex
glass test tubes. Also, make certain you have ample ventilation when mixing the ammonia solution. Dissolve in 1 oz. water a single crystal of silver nitrate. The
crystal should be somewhat larger than the head of a match. Begin adding drops of the ammonia solution to the dissolved silver nitrate until the water first
becomes brown, and then just begins to clear. Add a drop of potassium hydroxide to this solution. Then again begin adding drops of ammonia water until the
solution just begins to clear. The solution will remain somewhat cloudy. Too much ammonia in the solution can dissolve the cuprous oxide coating and can
damage or ruin the cell. Stir the mixture while adding a single drop of the potassium sodium tartrate solution. The mixture is now ready and should be used
immediately.
Applying The Solution :
Temperature and variations in the chemical mixture can
dramatically change the time required to complete the silvering
process. The best way to complete this step is by simple visual
examination of the process as it proceeds.
With the cell on a flat surface, begin by carefully pouring the
silvering mixture on to the center of the cell. Remember to avoid
letting this mixture contact any exposed copper. A good trick is to cover with paint or lacquer any exposed copper surfaces on the face of the cell. Continue pouring until the liquid has covered as much of the
surface as you can . If all the exposed copper on the surface has
been properly protected with the lacquer, you can actually pour the solution until it comes right to the edge. Since water has an affinity for itself
called "cohesion", it won't spill over the edge. Very soon, a thin film of silver will begin to form over the cell's surface. The liquid should be
poured off when the red oxide is still slightly visible beneath the silver. allow the silvering process to go a little too long rather than not
long enough since some of the silver coating can be polished away.You should now have a smooth silver coating through which
the red oxide is barely visible.
Completing the Cell contact can now be made to the cuprous oxide face of the ell by means of a ring of lead or silver-coated wire which is
slightly smaller in diameter than the disk itself. With the ring held firmly against the disk, a protective coating of thin lacquer
can be applied. Make certain the lacquer does not come between the wire and the disk. With wires attached to the disk's copper back and the
lead or silver ring, the cell is complete. The disk can now be housed behind glass, mounted to a sheet of plastic, cast in a clear resin or
housed in any other enclosure you desire!
No comments:
Post a Comment