How Do Solar Cells Generate Electricity?
The technical term for a solar cell is a photovoltaic cell, where "photo" means light in Greek , and "voltaic" means electrical. The presence of light energy was first recognized in 1839; however, it wasn't until 1883 that the first solar cell was invented by Charles Fritts.
Research carried out by Bell Laboratories in 1954 brought on the formal advent of modern solar technology. Researchers at Bell Laboratories came upon a substance that responded particularly well to light energy. This substance was silicon.- The chemical properties of silicon in crystal form were found to be a good starting point in terms of making a substance that conducts light, or solar energy. Silicon by itself turned out to be a poor conductor due to its electron configurations. However, researchers found that silicon combined with phosphorous and boron provided an effective semiconductor environment for light energy to be harnessed.
The term "doping" is used to describe this mixing of silicon with phosphorous and boron. While silicon electrons and phosphorous electrons meshed quite comfortably, the boron atom serves as a type of electron magnet due to its shortage of electrons on its outer rim.
As a result, this led to phosphorous "tainted" silicon making up one half of a solar cell while boron "tainted" silicon makes up the other half. - Once light hits the cell's surface, the electron configurations of all three elements combined creates a current of free electrons that can be directed and used by an external source, such as a calculator.
The light hitting the cell jars electrons loose. The electrical field created inside the silicon-doped cell then becomes a diode force, capable of moving the freed electrons in a specific direction. By creating an external path that leads out of the cell, and then back into the cell, the current can be used by an external source as it runs this route.
Because silicon is the primary component of the solar cell's make-up, cost issues have come into play. The three types of solar cells made from silicon material are single crystal silicon, polycrystalline and thin film technology. Single crystal silican is the most widely used form and the most expensive. However, in this form, silicon is most efficient at harnessing light energy. Polycrystalline is a cheaper form, but less efficient. Thin film technology is less expensive to produce on a mass scale, though researchers question its strength and durability.
Further research has been done on organic-type solar cells, and also nano-material solar cells. Researchers look not only to reduce the costs of solar energy conversion but also to invent a more efficient cell model as well.
