A MORE SIMPLIFIED SOLAR CELL

The fabrication of a modem solar cell is very complicated and
a delicate process. In most cases, a large silicon ingot is grown
from a small crystal in an extremely clean and sterile environment.
Any dust or particle contamination even down to the
atomic level during the growing process can completely ruin the
ingot. Impurities must typically be kept to one part per billion.
The growing process itself is slow, and the very pure materials
required are extremely costly. Because of this, a single ingot
which is later sliced into thin cells approximately 0.05 centimeters
thick often costs thousands of dollars to produce.
This fact coupled with the general inefficiency (7-14 typically)
of even these modem cells has kept the price of photoelectric
cells too high to be competitive with other sources of power.
Someday, lower cost production techniques together with
higher efficiency will make widespread use of clean, renewable
solar energy possible. Someday solar cells will be a very common
Source of energy, the idea of deriving electricity directly from
sunlight will continue to excite the inventor and experimenter.
It is well known that if even 1 of the Sahara desert were
covered with the solar cells just described, it would more than
supply our worlds current energy needs. We will briefly outline
some of the processes and materials that are now being researched
for converting the use of solar energy into electricity.

You should have no trouble building the cells that will be
described in the following pages. Be cautious. Use good judgement
and common sense in handling the chemicals and heating
processes described. You'll find that a simple solar cell can be
constructed by a persistent student, Solar cells that can make
outstanding science fair projects.
The electrical output from the homemade copper cells in
this article will be well below that of modern commercial cells,
but the materials cost is also very low. Often a cell can be literally
produced for pennies! The loss in efficiency is probably more
than made up in the reduction of their price.
But again the Screen printed solar cells are far more powerfull
than the copper type solar cells.