A Simple Explanation of How Solar Cells Work
A solar cell converts light into electricity. Solar cells are made of special semiconductor materials such as silicon.
When sunlight shines on the cell, electrons are released from their atoms.
The electrons flow through the cell, creating electricity as they move. The more light that falls on the solar cell, the more power it generates.
What is used to make a solar cell?
A solar cell comprises of two types of semiconductor materials, N-type (negative) and P-type (positive). These are placed on top of each other to form a junction.
N-type semiconductors have extra electrons, while P-type semiconductors have “holes” which are missing electrons.
An n-type semiconductor is a phosphorus (P), arsenic (As), or antimony (Sb) impurities doped intrinsic semiconductor. The valence electrons of silicon in Group IV have four, whereas the valence electrons of phosphorus in Group V have five.
A p-type semiconductor is an extrinsic type of semiconductor. When a trivalent impurity (like Boron, Aluminum, or Gallium) is added to a pure or intrinsic semiconductor (silicon or germanium), it becomes a p-type semiconductor. Trivalent contaminants like boron (B), aluminum (Al), and gallium (Ga) donate valence electrons to the intrinsic semiconductor.
How do solar cells work to generate electricity?
The solar cell generates electricity by transporting electrons via the junction between the different varieties of silicon:
The upper surface is bombarded with photons (light particles) when sunlight shines on the cell. The energetic photons (yellow blobs) transport their energy down through the cell to the junction, knocking electrons loose from their atoms.
The electrons jump across the junction (the blue line) into the n-type silicon. They flow through wires on the front of the cell to an external circuit and ultimately to an appliance or the utility grid.
At the same time, holes are swept up by the electric field to the back of the cell, where they recombine with electrons.
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How Efficient Are Solar Cells?
Solar cell efficiencies range from 6% for amorphous silicon-based solar cells to 44.0 percent with multiple-junction manufacturing cells and 44.4 percent with multiple dies combined into a hybrid package.
Solar cell energy conversion rates for commercially available multicrystalline Si solar cells are generally 14–19%.
Types Of Photovoltaic Solar Cells
The first-generation solar cells utilize a single, basic junction between n-type and p-type silicon layers obtained from distinct ingots.
The dopant used in an n-type ingot is phosphorus, antimony, or arsenic, whereas the dopant in a p-type ingot is boron. Slices of n-type and p-type silicon are then placed on top of each other to form a junction.
A few more components (such as an antireflective coating, which increases light absorption and gives photovoltaic cells their distinctive blue color, protective glass on the front and a flexible backing, and metal connections so that the cell may be linked to a circuit), but the basic structure of most solar cells is a p-n junction.
Solar cells are composed of thin wafers—often about 200 micrometers (200μm) or less in depth.
Solar cells, however, are far thicker than second-generation cells known as thin-film solar cells (TPSC) or thin-film photovoltaics (TFPV), which are around 100 times thinner.
Although most are still produced from silicon (a distinct form known as amorphous silicon, a-Si, in which atoms are unevenly positioned rather than precisely organized in a regular crystalline structure).
Some are now manufactured from diverse materials, notably cadmium-telluride (Cd-Te) and copper indium gallium diselenide (CIGS).
Second-generation solar cells may be applied to windows, skylights, roof tiles, and other “substrates” such as metals, glass, and polymers because they are extremely thin, light, and flexible.
The newest technologies combine the best characteristics of both first and second-generation cells. They advertise relatively high efficiencies (about 30% or more).
They’re also more likely to be constructed from materials other than “simple” silicon, such as amorphous silicon, organic polymers (making organic photovoltaics, OPVs), perovskite crystals, and feature numerous junctions (made up of multiple layers of various semiconducting materials).
With that in mind, they should be cheaper than both first and second-generation solar cells, as well as more readily available in large sizes.
Power Can Produced With Solar Cells
How much power does a single solar cell produce?
A typical silicon solar cell generates around 0.5 volts. The output current is determined by the cell’s size. A standard commercially available silicon cell produces a current ranging from 28 to 35 milliamperes per square centimeter of surface area. Dividing the wattage of a solar cell by its voltage gives you the current output in amperes.
Related: What’s the Difference Between a Solar Cell and a Solar Panel?
How much power can a solar panel generate per day?
The amount of energy a solar panel can create is determined by a variety of factors, however, you may anticipate a typical single solar panel in the United States to produce about 2 kWh per day, saving approximately $0.36 in power costs each day.
The Difference Between Solar Cells and Solar Panels
Solar panels are made up of photovoltaic cells, which are the main component in a solar panel, and solar systems include solar panels.
A single photovoltaic cell can convert sunlight into energy on its own, but the panel is required to combine and direct the output of many cells to your inverter and home.
Now you know how solar cells work and what the difference is between solar cells and solar panels.
Solar panels are made up of many solar cells, which are required to generate enough power for your home.
If you have any questions about solar panels or solar energy in general, please don’t hesitate to reach out to us!
We would be happy to help you learn more about this renewable resource.