Solar technology has been in the works for a long time. And we have finally reached a point where we can say that this technology is ready for use. Through research and improvements, this technology’s efficiency has gone up and its cost of production has gone down. A solar panel has the ability to produce electricity from sunlight. How they do this can be understood by studying the materials that are used to make these panels. Let’s take a look at the construction of a solar panel.
Understanding The Solar Panel
A solar panel is made up of solar cells. A solar cell is basically a thin layer of silicone that is layered in semi-conductive materials. One side has positive type semi-conductors and the other has negative materials.
When a solar cell is exposed to sunlight, the electrons in the semi-conductors get excited. And since one side of the cell has more electrons in the other, this excitement results in electrons being exchanged between the two sides. This back and forth movement of electrons creates electricity. The positive side of a solar cell can be connected to a wire in order to transfer this electricity.
This is what goes on inside of a solar panel. There are a number of solar cells constantly producing electricity. The efficiency and longevity of this energy production is determined by the type of materials used in making the solar cells.
Evolution of The Solar Cell
Silicone has been a common material in solar cell manufacturing since 1954. The photovoltaic effect (that takes place within a solar cell whenever it gets exposed to sunlight) was discovered way before this. It was discovered by a French physicist in 1839.
The huge gap between the discovery and actual implementation of this effect was because of material availability. In 1873, it was discovered that selenium was a good material for photoconductivity. This led to progress in the creation of the solar cell. Photoconductive materials made it possible to develop a solar cell that would work without requiring heat or moving components.
The first working solar cell was developed in 1883. It used selenium as its photoconductive material. However, this cell was far from efficient since selenium itself is not an efficient material.
In 1905, Albert Einstein wrote a paper that elaborated on the workings of the photovoltaic effect. All this research and experimentation paved the way for improvement over the years. In 1954, we managed to find materials that made usable solar cells.
Silicone is a major improvement over selenium. However, it is not perfect either. The material is bulky, brittle, and its manufacturing process is difficult.
Types of Solar Cell Materials
Nowadays, we make solar cells from a number of different materials. Some of the first high-production solar panels were made using monocrystalline solar cells. A monocrystalline cell is made from a large piece of silicone that has been cut into thinner slices. In order to make this type of silicon, it needs to be processed until it reaches a purity of 1 part per billion. Reaching this level of purity requires a lot of heating and gradual cooling.
This super purified silicone is coated onto a seed rod in order to create a silicon wafer. After it cools down, doping material is applied to either side of the wafer. One side of the wafer has a negative coating and the other has a positive coating. Finally, an additional transparent layer is set to cover one side of the wafer. This side is from where the cells will be exposed to sunlight.
Monocrystalline panels are quite common nowadays. They offer great efficiency but they are also quite expensive thanks to the lengthy and complicated manufacturing method.
Polycrystalline Solar Panels
Polycrystalline solar panels use silicon as well. However, their production method is less expensive. They have a uniform crystal formation in them, but the size of individual crystals is significantly smaller. Polycrystalline Solar Panels have a blue color to them as compared to monocrystalline ones that are black in color.
Amorphous Silicon Solar Panels
This kind of solar panel is quite cost-effective. This is because Amorphous solar panels can be mass-produced quite easily. Instead of manufacturing silicon and then applying doping materials to it, amorphous panels are made layer by layer. A 1000 feet long plastic sheet is prepared for material application.
All of the solar cell materials get layered onto this sheet, producing one massive solar cell. This cell is then cut into smaller pieces in order to fit it into solar panels. The manufacturing process is quite flexible, allowing for a wider application of the cells being produced. The only downside is that efficiency gets compromised.
Cadmium Telluride (CdTe)
CdTe Solar panels make use of different materials. Their manufacturing process and operation is more or less the same. They are also really cost-effective and efficient. But Cadmium is a really toxic material, making the manufacturing process harmful.
Also, these solar panels tend to have a shorter lifespan. The toxic nature of Cadmium makes these solar panels an environmental hazard. Fortunately, they can be recycled safely if proper care is taken.
Copper Indium Gallium Selenide (CIGS)
CIGS solar panels are incredibly efficient and also incredibly expensive. They use a bunch of materials to achieve the photovoltaic effect.
A CIGS solar cell consists of a transparent conductive layer of CdS (Cadmium Sulfide), ZnO (Zinc Oxide), and an anti-reflective layer of MgF2 (Magnesium Fluoride).
The extra materials used make production more complicated. This results in solar panels that can be pretty expensive.
Organic Photovoltaic Cells
Organic Photovoltaic Cells (OPVs) are made using organic polymers. OPVs are cost-effective since organic polymers are quite plentiful. They can also be produced in different kinds of colors. But they have shorter lifespans and considerably lower efficiency levels. OPVs are primarily used in building-integrated photovoltaic applications.
Perovskite Solar Cell
This kind of solar cell gets printed rather than manufactured. All of its materials are applied in ink form and they are capable of absorbing the entire light spectrum. Perovskite Solar panels are quite cost-effective and have high efficiencies.
Compared to 1954, we have a lot more types of solar cells now. Each type has its own pros and cons. A great thing about solar technology is that we are continuously seeing a lot of innovation happening in this field. In the near future, we can expect this technology to only get better. And as this happens, we will be able to apply solar technology in a variety of new ways.