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What are the differences between polycrystalline, monocrystalline and thin film?

Many brands of solar panels, many sizes, capacity ect, that is to say the solar panel market is flooded with them, this forces you to know the Differences between monocrystalline, polycrystalline and thin film solar panels if you are interested in solar energy to your home .

¿What are the differences between polycrystalline, monocrystalline and thin film?

The majority of solar panels are composed of silicon, so the purity of this chemical element in the cell and the processes used to obtain it for the efficiency of solar panels is of paramount importance since it determines the capacity of the cell to transform energy

Some terms to better understand the article:

Crystal structure:

It is the dimensional network that extends to the entire solid, orders and packages the molecules, ions or atoms. In other words, it’s like atomic architecture.

Crystal structure FCC (face center cubic)

Grain:

It is what makes up the border of grains, they are small portions within the material in which the atomic arrangement is the same, but the orientation of each of the grains is different. The shape and size of the grains influence the behavior of the metal.

  1. Coarse grain:  The larger the grain has a lower electrical conductivity because the grain limit prevents the movement of electrons.
  2. Fine grain:  As long as the grain is smaller, there will be greater mechanical resistance because dislocations are prevented from moving. Dislocations are anchored thanks to the grain border preventing their movement. A single crystal resists traction better than polycrystalline.

It can be analyzed as in the monocrystalline it is noted that they are uniform compared to the others.

Grain Limit:

This name is called the area where the grains are separated, it is a narrow region between grains. They are generated during solidification when the crystals have been formed by different nuclei. They grow by joining with each other. You can alter the properties of a metal by controlling the size of the grains.

                                                                   Border or grain limit

Monocrystalline silicon cells:

They are manufactured with a high purity of silicon so the crystalline structure is uniform, electrons generate a greater interaction so they generate greater efficiency. They are considered in comparison to others as cells with greater performance due to their good ability to convert solar energy to electricity. They are very easy to recognize these cells for their color and uniform appearance, this indicates that they are made of high purity silicon.

They are made of cylindrical silicon ingots. When manufacturing the cells the ingots are cut on four sides, they are in the form of wafers which is a characteristic aspect of these cells. This process is used in order to optimize performance and reduce costs.

Advantage:

  1. The efficiency rate is generally 15-20%, they are the panels with the highest efficiency rate.
  2. They are better in terms of electricity generation and their size is not as large as that of polycrystallines, a smaller cell produces more than a larger size of polycrystalline and also produces up to four times the amount of electricity than those of thin film
  3. The fact of being monocrystalline causes it to have a better performance in low light conditions.
  4. Because they are made of high purity silicon and their grains are thin they have a greater resistance. Most manufacturers give a 25-year warranty on this type of panels.

Disadvantages:

  1. It is advisable for these panels to buy microinverters because it is very common for circuits to break down with brush, earth, snow or even with a little shade. The microinverters are recommended to compensate for the potential risks generated by dirt or shadow, they are responsible for reducing the effects to only one solar panel so that the whole structure does not run out of energy.
  2. Due to their manufacturing process they are the most expensive panels and in addition they are of high purity of silicon.
  3. Due to its manufacturing process, forming ingots of cylinders and cutting them causes a lot of waste.
Differences between monocrystalline, polycrystalline and thin-film solar panels
Monocrystalline cell. 

Polycrystalline silicon cells:

These solar panels have been incorporated into the market since 1981. In comparison with monocrystalline products, these are not manufactured by the Czocharalski process because this process generates many wastes. These cells are manufactured differently, the silicon is melted and placed in a square mold in which it is cooled and cut into square shapes.

The grain structure has different orientations, it can be analyzed in the grain limit as the fact that the grains are not uniform cause that a lower efficiency is obtained, also generates that the grains impede the movement of the electrons and there is a greater resistance mechanics. The lower the movement of the electrons, the lower the efficiency in the cell.

Advantage:

  1. As another process is used that is not cutting cylindrical ingots the amount that is wasted is less and the process used is cheaper and simpler.
  2. They have lower cost compared to monocrystalline panels
  3. They tolerate heat quite a bit except in extreme circumstances.

Disadvantages:

  1. They are not as aesthetically pleasing as monocrystalline and thin film cells. Its color is of different shades of blue.
  2. They do not have the best efficiency because their grains are not uniform and there is no great movement of electrons as in monocrystals. Its efficiency is generally 13-16%.
  3. These panels are quite large compared to monocrystalline and thin film, in addition to not producing more efficiency because they are larger, they only take up more space.
Differences between monocrystalline, polycrystalline and thin-film solar panels
Polycrystalline cell

Thin film solar cells (TFSC)

E hese cells are made of different materials, photovoltaic material meets to separate paper in thin layers. Depending on the substrate that is placed is the type of thin film that is generated, there are different types such as:

  1. Cadmium Tellurium (CdTe)
  2. Amorphous Silicon (a-Si)
  3. Gallium and Indian selenide (CIS / CIGS)
  4. Organic photovoltaic cells (OPC)

The most common found are amorphous silicon cells, these cells are also based on silicon, but it does not have a crystalline structure so you can group the particles randomly.

Advantage:

  1. Because the grains can be structured randomly, they are manufactured homogeneously so their design is visually attractive.
  2. They are used for different applications, they are quite flexible.
  3. They have a good size so they do not require much space.
  4. Its efficiency of approximately 7-13%, the manufacturers of these cells expect that in the next models they will have efficiency of 16%
  5. They are easy and cheap to make so their prices are more accessible.

Disadvantages:

  1. Your warranty is short because they are not estimated with a long use life
  2. They do not always come complete with the entire system of photovoltaic equipment necessary to perform the installation, so you have to be aware that it is what you buy.
  3. They do not generate so much power compared to monocrystals.
Differences between monocrystalline, polycrystalline and thin-film solar panels
Amorphous silicon cell

As a recommendation:

Existen diferente tipos de paneles solares con características diferentes para que seleccione el que más se le acomode, si quiere un panel solar con la mayor eficiencia elija un sistema compuesto por celdas monocristalina ademas son atractivamente visuales pero tenga en cuenta que el costo sera más alto.

Si prefiere tener un menor gasto y no le interesa como se ve (muchas veces como van en el techo no se ven) elija un sistema con celdas policristalinas, su eficiencia sera menor pero aceptable. Si le interesa como se ve visualmente y no quiere tener un gran gasto compre de película delgada pero tenga en cuenta que la eficiencia es menor en comparación con los anteriores. N

We recommend monocrystalline solar panels, they are the ones that have the greatest efficiency and are visually appealing. The purpose of using panels is to generate as much energy as possible to reduce the expenses of the electricity bill and generate renewable energy.