The photovoltaic effect is and will always be one of the great discoveries of history. This was discovered by Frenchman Alexandre Edmond Bequerel in 1938 while he was experimenting with an electrolytic cell with platinum electrodes and when he was only 19 years old, he verified that the current rose in one of the electrodes when it was exposed to the sun.
How does solar energy become electrical?
From that rudimentary experiment to date, photovoltaic technology has evolved a lot, and today we can find powerful solar panels that are capable of producing up to 500W.In this article we want to explain to you exactly what the young Frenchman discovered in the 1930s, but applied to the current situation. Next, we look at how solar energy can be converted into electricity. Read on to stay up to date!
When was the first photovoltaic cell created?
As we said, the discoverer of photovoltaic energy was Alexandre Edmon Bequerel in 1938, however, the creator of the first photovoltaic cell was Charles Fritts in 1883 . These first solar panels were made with selenium covered by a thin layer of gold and their cells had an energy conversion rate of 1 to 2% each.
How is photovoltaic solar energy transformed into electrical energy?
To answer this question, you must first understand what a solar panel is made of and how its structure allows the conversion of solar energy to electricity. The solar panel is one of the most important parts of the photovoltaic installation. This is made up of a large number of cells that vary depending on the power they offer. For example, a 250 W panel (the most common) is made up of 60 photoelectric cells that are connected in 6 rows of 10 cells each. Each of the cells is responsible for generating electricitydue to the materials with which they are made (generally, about 10 volts are obtained for each of them). These are made of crystalline silicon (although we can also find some models made with gallium arsenide cells), two semiconductor materials that carry out this conversion of solar energy to electricity.
Now, exactly how does solar energy go into electrical? The first thing to know is that silicon by itself does not generate energy, only when exposed to the sun. The reason why it is possible to capture solar energy and convert it into electricity is because these cells are connected to each other forming a kind of circle – which is what we know as the solar panel. The silicon in the cells creates the positive and negative charge in the solar panels because they are made up of millions of atoms that give off both charges depending on their exposure to the sun and their location, thus creating an electric field. The radiation absorbed by each cell causes a jump of electrons from one layer to another, at which time the electric current is generated.
What is the photovoltaic effect?
Now that you know how solar energy can be converted into electricity through solar panels, we are going to see in more detail how sunlight is transformed into electrical energy through the photovoltaic effect and delving into details. As we said above, when the electron jumps from one side to the other through the semiconductor materials, the current is created —by the way, for this to be possible, the strength of the radiation must always be greater than 1.2 eV—. This is so because the atoms without electrons are left with a hole that must be occupied, it is what is known as the electric charge.. Electrical charges, as long as they are generated continuously, can be extracted and used for their own benefit. Now, for this it is necessary that there is an electric field. This takes place within traditional solar cells due to a junction in which the area with a negative electrical charge (due to an excess of electrons) and a positive one (due to a lack of protons) differ.
The electric field distributes the electrons in the opposite direction to that of the holes that appear. When the electron is released, it is pushed from one side to the other until it reaches the silver conduits, thus finally being used.
Types of solar cells and which ones produce the most energy
As we said above, the main material with which solar panels are made is silicon. Now, there are several ways to manufacture them and not all of them offer the same performance. Silicon can be polycrystalline, monocrystalline and amorphous.; Of these three options, the one that produces the most energy is the monocrystalline one, but it is also the most expensive. Keep in mind that to design solar panels with monocrystalline cells, the material is sectioned into cylinder-shaped pieces, that is, whole pieces are obtained and no material is wasted. Polycrystalline cells, on the other hand, are made by melting various silicon glasses. Now, although it is less profitable, it is easier to produce and the difference is not so high —in fact, this is one of the most used materials in the process—. And it is that polycrystalline cells or polysilicon meet high performance and greater efficiency linked to the price of the material and manufacturing.
What other elements influence the conversion of solar energy to electricity?
There is another essential element in the photovoltaic solar installation that plays an essential role when it comes to answering the initial question of how solar energy can be converted into electricity, this is the inverter . The solar inverter is a device that allows us to take advantage of the electricity generated in the solar panels in a way that does not affect the electrical installation of our home, business or any other point where the installation is located. This is responsible for transforming the direct current that is created in the solar panels into alternating current, allowing it to reach the electrical components or appliances in the home without damaging them —since the current used by most appliances is alternating current—. The solar inverter, on occasions, can fulfill other functions, such as that of a battery-charger inverter.