What Are Solar Cells?

Solar cells can also be named as the photolytic cell. It is a cell which captures solar energy. Actually, solar cells store the sunlight and then transform it to the electrical energy, through photovoltaic effect. Solar cell was invented just a few years back and since from then its concept has been developed a lot.

Working of solar cells
Working of solar cell is extremely easy to understand. Solar cell possesses some kind of semi-conducting material, which absorbs the photons emitted by sunlight. Silicon is the most common semi-conducing material which is used to construct the solar cells, but other cheaper semi-conductors can also be used to decrease the cost of production. These absorbed photons cause the release of electrons from the host atom of the cell material. These free electrons move as electricity, this generated electricity then pass through an array arrangement, where it gets converted into DC (direct current). This DC can be easily converted into AC (alternating current), by using simple electrical equipments.

History of solar cells
This photovoltaic effect was introduced in earlier years of 19th century. Then in 1880, for the first time, this idea was applied practically by creating first solar cell. This cell was generated by using selenium as the semi-conducting material. This cell was just 1% efficient, means it was able to capture only 1 % of the total amount of solar energy which was hitting on the surface of the cell.
Then in 1954, bell labs concluded that silicon can be modified, and they generated a new form of silicon which was extremely photosensitive. This modified silicon bought a revolution in field of solar energy. Then in 1958, a special satellite named as “the vanguard 1” was launched, this satellite was enabled with solar cells, as its main source of energy. With this feature of solar energy, this satellite was able to remain in its geosynchronous orbit for indefinite period of time, because it was having no dependence on the limited fuel.

By 1988, such solar cells were available in markets which were having efficiencies of 17%. Then to increase the efficiency of solar cells, a new strategy was introduced in the field of solar energy production. It was suggested to use a lens in order to focus the sunlight on a particular solar cell. These new “lens enabled solar cells” were showing efficiencies of 37%.

Generations of solar cells
Solar cells can be classified into three categories, which are said to be three generations of the solar cell-
1. First generation of the cells is the most commonly used solar cells. These cells have maximum efficiency around 33%.
2. Second generation solar cells are cheaper then first generation solar cells. Their production procedure is also very simple. They can be simply generated by using simple techniques like vapor deposition and electroplating. These cells consist of a thin layer of cadmium telluride, enclosed in a very thin sheet of the glass or ceramics.
3. Third generation solar cells are based on the technology of second generation cells, but they have slightly improved efficiencies. Efficiencies of third generation solar cells vary between 30-60%.

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