Building the basic components of solar photovoltaic panels is not a simple process; in fact, making actual solar cells from scratch is virtually impossible without the use of high-tech, specialized tools. You can put photovoltaic panels together easily enough once you have the cells, but the manufacture of solar cells themselves is a highly complex process. (By the way, the word “photovoltaic” is a fancy word for the process by which sunlight is converted directly into electricity.)
A Cell Is Born
It’s the photovoltaic cell itself that converts sunlight into actual electric current. It has several other uses as well; they can be used in surveillance equipment that allow law enforcement to “see” through walls by detecting infrared radiation as well as other types of electromagnetic radiation. It can also be used to measure light intensity, and therefore assist photographers in calibrating their cameras, and to measure certain chemical reactions under lab conditions.
The first step in crafting a photovoltaic panel is to obtain a semiconductor. Usually, this is pure silicon, which is produced from quartz. The silicon is melted down and combined with trace amounts of boron or phosphorus, then allowed to cool into a block shape. This block is then cut into thin wafers and the surfaces are carefully etched and cleaned.
The next step is to place these wafers into what is known as a diffusion furnace. This exposes the wafer to extremely high temperatures, which cause the formation of an N-Type semiconductor. The “N” in this case stands for “Negative;” this heat treatment creates an abundance of negative electron charges, which is what helps to produce direct current when direct sunlight hits the surface.
But wait – we’re not done, yet! The surface of the wafer must then be painted with an anti-reflective coating. After all, we want our photovoltaic cell to absorb sunlight, not bounce it back into space! Once this is accomplished, the electrical contacts are imprinted on the top.
What’s missing? Ah, yes…the P-Type, or positively-charged surface. This is created on the bottom, or back side of the photovoltaic cell, using a form of aluminum.
Putting It Together
Once the cell has been tested, it is connected to other cells to form solar photovoltaic panels. You can now appreciate why these little devils are so expensive to manufacture. The good news is that new technologies – particularly nanotech, or the use of microscopic machines built at the molecular level – is dramatically lowering the cost of this process.