How Are Solar Panels Made? Crystalline and Amorphous Solar Panels
It is fascinating that the energy freely available from the sun can
be harnessed for our energy needs. Solar panels installed on rooftops
and in residential yards are being used to power our homes.
How are solar panels made?
Solar cells are the semiconductor
building blocks that convert light directly into electricity. If
you string these small electric generators end to end, you can
create a large solar panel that will be able to produce enough
electricity to power lights, appliances and even entire households.
The key ingredient to this photovoltaic magic is silicon.
Silicon is an element found in great abundance on the surface of the
earth. It’s mainly in the form of silicon dioxide and is also known
as sand. It is the key ingredient used to make the two main types of
solar panels: crystalline and amorphous.
Crystalline Solar Panels:
- Produces more power than amorphous solar panels so fewer panels
are required to produce the same amount of electricity.
- Use more purified silicon and therefore are more expensive.
- Are more reliable and can last for 30-40 years.
- The structure is rigid and cannot be bent. Careful handling is required.
Making crystalline solar panels requires plenty of time, energy &
material. A cylindrical column of pure silicon (99.99999% pure) is grown
in a high-temperature furnace and then cut into very thin wafers. Each
disk is 1” to 12” in diameter and is then reheated at high temperatures
where phosphorous and boron is doped into the rigid disk.
Once cooled, the thin disks of N-Type and P-Type semiconductors are
cleaned with mild acids and textured to create a rough surface. A rough
surface has more surface area which increases the solar cell efficiency.
The disk is then cut to fit the final product.
Wires are attached to either end of the solar cell to create a chain.
As the chain increases in size, the more current it can generate. The
chain is then laid in a rigid panel and a layer of glass is placed on
top for protection. The transparent glass allows light to pass through
yet provides enough structural integrity to withstand outdoor temperatures
and rough weather.
Amorphous Solar Panels:
- Use less semiconductor material and are therefore cheaper to
manufacture and to purchase.
- Are much thinner, so panels can be flexible and more convenient to handle.
- Require more panels to produce the same amount of power as crystalline solar panels.
- Reliability is reduced since the layer of semiconductor material is so thin.
Unlike crystalline solar panels, these panels are not made up
of a chain of solar cells. At very high temperatures, a thin layer of
silicon, phosphorous and boron is sprayed onto a backing material.
The layer is thinner than a human hair. The backing material can
be glass, metal and even plastic to make solar-powered products such
as solar glass, solar roof tiles and even flexible solar panel rolls.
And entire surface can be coated with this ‘spray-on’ solar panel.
Costly wires are not used nor are expensive silicon wafers needed.
What’s in the Future for Solar Panels?
Solar energy from the sun is made of electromagnetic radiation of
various wavelengths. Some of these wavelengths can be seen with our
human eyes and show up as colors. Others we can not see yet still
hit the surface of the earth.
Multi-junction photovoltaic cells are new amorphous solar cells
made up of layers of semiconductor material where each thin layer
can generate electricity from different wavelengths. Each layer
captures a certain wavelength of the sunlight as it passes through
the panel. By stacking multiple layers on top of one another, more
electricity is generated in the same amount of surface area as one