Solar cells of copper without NaCl?

[jadaro2600]

from : http://www.zetatalk.com/energy/tengy17f.htm...

    Solar cells can be made out of cuprous oxide. Here is the process briefly:

    Use a sheet of copper (.025" thick), It should be in the shape of a circle cut out of a square, with one corner of the square left.

       1. Clean the copper sheet very thoroughly, it may be necessary to use nitric acid.
       2. Heat the copper red hot. Use a propane torch, and make sure it is heated red all over. Keep the torch on one side of the cell, do not let the flame touch the other side. Keep it red for a 2 min 40 sec. This will cause two types of copper oxide to form on the side away from the flame. Cupric oxide is the black flaky stuff that forms. Under this is pinkish cuprous oxide. Lightly rub the cell with coarse steel wool to remove the cupric oxide. Be sure not to damage the cuprous oxide. If the whole side of the cell is not covered, repeat the process. If it is not covered with cuprous oxide on the edges, just cut off the edges.
       3. Cover the side with the cuprous oxide with a silvering solution. (so there is a transparent film covering the oxide). Solder a wire to the back (copper side) and another wire to the front (silvered side). The cell is now done, and will produce electricity when exposed to light.

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Can anyone clarify what this meant by ..silver the side to create a transparent layer?  it seems contrived.  perhaps I misunderstand the silvering solution?

[mscoffman]

Can anyone clarify what this meant by ..silver the side to create a transparent layer?  it seems contrived.  perhaps I misunderstand the silvering solution?

This sounds legitmate to me.  You know, about "silvering a piece of glass" to form a
mirror. There is a form of a mirror called a "half silvered mirror", or a one way glass,
that lets some light photons pass through it. The surface will also be electrically
conductive.

Telescope makers have to silver a mirror for Newtonian telescope optics.
So knowledge of how to do this probably reside with astronomy hobbiest.
Original Lasers also use a "half silvered mirror" at both ends. So knowledge
of how to do probably resides with Amateur laser builders.


abstracted from Wikipedia;
-----------------------------------------

Aluminizing or "silvering" the mirror

Once the mirror surface has the correct shape a very thin coating of a highly reflective
material is added to the front surface.

Historically this coating was silver. Silvering was put on the mirror chemically, typically
by the mirror maker or user. Silver coatings have higher reflectivity than aluminum but
corrode quickly and need replacing after a few months.

Since the 1950s most mirror makers have the coating applied by a thin-film deposition
processes (work that has to be done by a firm specializing in the process). Originally the
coatings were aluminum. Modern coatings usually contain aluminum and other
compounds.

The mirror is aluminized by placing it in a vacuum chamber with electrically heated
tungsten or nichrome coils that can evaporate aluminum.[5] In a vacuum, the hot
aluminum atoms travel in straight lines. When they hit the surface of the mirror, they
cool and stick. Some mirror coating shops then evaporate a layer of quartz onto the
mirror, whereas others expose it to pure oxygen or air in an oven so that the mirror will
form a tough, clear layer of aluminum oxide.

-----------------------------------------

A similar process is used to make the original small non-emitting LCD liquid crystal
displays because the front conducting layer needs to be both conductive and yet
relatively invisible. But with a different metals from the ones discussed above.

:S:MarkSCoffman

[jadaro2600]

so this is more like a solar diode then.  It's like a thermojunction..?


I found a link to the full set of instructions here in pdf format.

[onthecuttingedge2005]

so far there is no solar tech that can surpass Germanium, it has problems with expense. slicing it super thin is another. it is the most efficient semiconductor at converting solar radiation to electricity.

Germanium Oxide might provide some good results but probably not as efficient as pure Germanium. Germanium Oxide is cost efficient in some countries if bought there.

[triffid]

I made copper oxide solar cells in the early 1990's.I got the red oxide layer on the sheet of copper.Heated the copper sheet on top of the kitchen stove,watched it turn black.Plunged the sheet into tapwater to knock off the black oxide to expose the red oxide underneath.Put rusted window screen on one side(as my collecter) press it firmly against the red copper oxide.Placed elmers glue on top.It dries clear.The other side I scraped down to the bare copper in one small spot only.Touched voltmeter leads to the window screen lead and to the bare copper spot on the other side and got a reading.I never used salt or salt solution.They don't produce a lot of power.Only about 1% efficient which is why I stopped working with them.Triffid