That’s right! Your solar energy panel is primarily made from silicon, an element which is found in sand. Well how does it happen?
The key steps in the process are as follows:
– Silicon refinement
This is where the sand gets taken from the picture above refined and melted into pure silicon blocks. (Depending on the exact process these can be blocks of Mono/Multi/Amorphous-crystalline silicon)
– Saw Damage Etching
The blocks are cut into thin wafers and in doing so there is some damage that takes place on the surface and in order to get rid of the damage the manufacturer will chose to etch away at the surface.
This is usually done after the wafers have been sliced and its purpose is to create a surface where the absorption of light is maximized.
– Emitter Diffusion
This is a step that optimizes the solar cells ability to generate electrons, throughout the cell, that will in turn create current flow.
– Edge Isolation
This is done to make sure that the electrons, generated by sunlight, will be directed towards the fingers on the top and not the edge of the cells.
– Anti-reflection Coating
As suggested by the word this is a coating applied to the cell towards the end that helps to reduce the amount of front surface reflection and to maximize total-internal-reflection.
– Rear and Front Contact Printing
These are the metal strips that you see on the front of the solar panel. You can’t see the contacts on the back but this is done before the cells are connected to each other to form a module. This process is crucial because it will determine the ability of the cells to transmit the electricity from the cell to the module and to your appliances.
Co-firing will drive the paste that was printed on the cell in the previous step into the cell so that it makes a good ‘ohmic’ contact with the area where the electrons are being generated! It also turns the paste into the solid metal fingers you see on the top of the solar cell.
(Video to describe this process to come soon!)
Written by Prateek Chourdia
MEngSc – Photovoltaics and Solar Energy, UNSW
Solar Energy Analyst
© 2010 Solar Choice Pty Ltd