4 interesting facts about Photovoltaic cells

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#1.History of photovoltaic cells

Talk about photovoltaic cells and their use began in the last decade, and Sharp was the first company to produce solar panels in a commercial form in the world in 1963, and after that, NASA used solar cells on astronomical observatories, and that was in 1968 when a panel was installed A solar capacity of 1 kilowatt on the surface of an astronomical observatory.

The official launch of solar energy, in general, was in the year 1973 when the global oil crisis occurred when the Arab countries cut off oil from America and the West, and the world began to think about alternative solutions and options for oil, which are renewable energies.
After that, research and studies on solar cells continued and were greatly developed

#2. What is a Photovoltaic cell?

Photovoltaic cells are used to generate solar energy, Its purpose is to capture the sun’s radiation, it’s light, to convert it into electricity.

A solar cell, or photovoltaic cells, can work on its own, when needs are lower, for example, a solar calculator or a pocket inhibitor, But to meet the greatest needs they are assembled into solar panels and linked together on a sequence or branch to produce electricity

#3. How photovoltaic cells are made?

Solar cells are made mostly of silicon extracted from pure silica rocks or sands where we melt these rocks in special furnaces to produce raw silicon with a purity exceeding 95% and then chemically treated to reach 99,9999999% so that it is used to produce high-purity silicon crystals that are used In microprocessors and microelectronics, or with relatively less purity, it is used in the manufacture of solar cells.

After the production of silicon wafers, their surfaces are chemically treated and a layer of phosphorus or boron is added to reflect the thin polarity of the silicon, thereby creating a double joint capable of separating the current mounts that are produced when exposed to sunlight.

Silicon nitrate material is used to paint the surface of the cell and give it a blue color so that the reflection of the light falling on the cell will be foiled and given a greater chance to enter the cell. After that, the process of printing the silver conductor network on the front surface and the aluminum mesh on the back surface is heat-treated and thus the solar cell is ready to produce electricity.

After that, the process of printing the silver conductor network on the front surface and the aluminum network on the back surface is heat-treated and thus the solar cell is ready to produce electricity. These cells are grouped into rows in a row to increase the voltage difference or in parallel to increase the current in a process that is relatively similar to the way ordinary batteries are used. Therefore, some people like to call them solar batteries.

The cells combined together are called the solar panels and collect these panels in a similar way to get a matrix of solar panels, which we connect to the regular electricity network after we convert the direct current into alternating current using special transformers for this process.

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#3. Three Generations of photovoltaic cells

First-generation

Photovoltaic cells are made from semiconductor materials, which are silicon Most common and used due to the availability of its sources all over the world. The cells were large It is flexible and has a high manufacturing cost. As a result, silicon wafers are less absorbent

And absorbing solar rays, this led to an increase in its thickness from 125 to 252 mm, They represent a very large thickness compared to wafers made from other semiconductors such as gallium arsenic which is about one micrometer thick.

So the cost of producing electricity from the first-generation cell products was very high, which arrived at 5 USD per watt.

In general, silicon solar cells are still the dominant commercial ones (around 35%) when they are characterized Its high efficiency

Second-generation

Solar cells from thin films, which depend in their production on several advanced methods, including the chemical vapor deposition method, which is summarized in the manufacture of thin films of semiconductor materials deposited on glass or plastic bases) These bases are deposited.

Thin films of semiconductors to form a photovoltaic unit.

These cells have the advantage of having a thin thickness of not more than one micrometer, meaning that their thickness is less About the thickness of the silicon chips used in the first generation of cells by about 100 to 1000 Once.

As a result, the cells became lightweight and flexible, which distinguished them for use as an energy source With mobile devices such as phones and laptops, but their efficiency is still low and reliable

Within 12%, the reason for the low efficiency is that the thickness of the second generation cells is very thin.

Consequently, it does not absorb the same amount of solar radiation spectrum that the slides absorb

Silicone thicker (produced in the first generation).

Examples of second-generation cells include; amorphous silicon, Nanocrystalline Si, Cadmium telluride

Third-generation

This is known as the “nanotechnology” generation.

Products of this generation are still in the stage of research, evaluation, and development at the experimental level

The laboratory is expected to have a wide range of creativity.

Pigment solar cells are one of the most important types of the third generation of photovoltaic cells, as it has several technical and economic advantages. Other cells include polymeric solar cells and nanocrystalline cells.

Crystalline silicon cells are the most common on the market, accounting for 72 percent

One of the benefits of using silicon in solar cells is that the amount used in solar cells can be reduced Its production is as follows:

In the year 2004 it was 13 gr / w:
In the year 2008 became 6.3 gr / w:
Access scheme to 5 gr/w

3 generations of photovoltaic cells [1]

#4.Photovoltaic Cells – How it’s work?

The solar cell works in several steps: Photons in sunlight hit the solar panel and are absorbed by semiconducting materials, such as silicon. Electrons are excited from their current molecular/atomic orbital. Once excited an electron can either dissipate the energy as heat and return to its orbital or travel through the cell until it reaches an electrode. Current flows through the material to cancel the potential and this electricity is captured.

The chemical bonds of the material are vital for this process to work, and usually, silicon is used in two layers, one layer being doped with boron, the other phosphorus. These layers have different chemical electric charges and subsequently both drive and direct the current of electrons An array of solar cells converts solar energy into a usable amount of direct current (DC) electricity. [2]

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