The sun is and will always be there! This may be too bold a statement, but it really is. At least from the point of view of humanity. Even if it explodes in a few million years, but by then we will have left this planet either by ourselves or as a pile of ash, which will be scattered in space by another huge rock that hit our blue ball. It is because of this stability of the Sun that it can and should be used to generate energy. People learned how to do this long ago and are continuing to improve solar energy technology. But how do solar panels, batteries, and in general, how do you turn light into electricity inside a socket work?
When did solar panels first appear?
Solar panels were invented quite a long time ago. The effect of converting light into electricity was first discovered by Alexandre Edmond Becquerel in 1842. It took almost a hundred years to create the first prototypes.
In 1948, on March 25, Italian photochemist Giacomo Luigi Cemichan was able to make what we now use and develop. Ten years later, in 1958, the technology was first tested in space as a power cell for an American satellite called the Vanguard 1. The satellite was launched on March 17 and the same achievement was repeated in the USSR on May 15 of the same year (Sputnik-3). That is, the technology began to be used en masse in different countries almost simultaneously.
Such structures are still used in space, as an important source of energy. And they are also used on Earth to power homes and even entire cities. And they are also being built into civilian electric cars to provide greater autonomy.
In general, the importance of such elements cannot be overestimated. This is the only way to get energy anywhere on the planet. Hydropower, nuclear power plants, wind turbines, and the like can be placed only in certain places, are very expensive, or require the appropriate infrastructure. And only solar panels allow you to build a house in the desert and electrify it. For relatively little money. It is definitely not enough for a “windmill”.
How do solar panels work?
It is worth a little clarification that the concept of “solar panel” is not very correct. More precisely, it is correct, but it has nothing to do with the power systems we are talking about. The battery there is a regular battery, but it gets its energy from solar panels, which convert sunlight into electricity.
A solar panel is based on photovoltaic cells that are placed inside a common frame. Silicon is most commonly used to create these cells, but other semiconductors are also possible.
Energy is generated when sunlight hits the semiconductor and heats it up. As a result, electrons are released inside the semiconductor. Under the influence of the electric field, the electrons begin to move in a more orderly fashion, which results in an electric current.
In order to get electricity, you have to connect the contacts to both sides of the photocell. As a result, it will begin to supply electricity to a connected consumer or simply charge the battery, which will then feed electricity back into the grid when needed.
The main emphasis on silicon is because of its crystalline features. However, pure silicon itself is a poor conductor and very few impurities are made to it to change its properties, which improve its conductivity. Most of the impurities include phosphorus.
How do semiconductors generate electricity?
A semiconductor is a material whose atoms either have extra electrons (n-type) or lack them (p-type). That is, a semiconductor consists of two layers with different conductivities.
The n-layer is used as the cathode in this circuit. The anode is the p-layer. That is, electrons from the first layer can transfer to the second layer. The transition occurs by knocking out electrons by photons of light. One photon knocks out one electron. After that, they pass through the accumulator and get back to the n-layer, and everything goes in a circle.
Modern solar panels use silicon as a semiconductor, but it all started with selenium. Selenium had an extremely low efficiency of no more than one percent, and people began looking for a replacement. Now silicon generally meets the industry’s requirements, but it has one significant disadvantage.
Treating and purifying silicon to bring it to a form in which it can be used is quite costly. To reduce production costs, they are experimenting with alternatives such as copper, indium, gallium and cadmium.
Efficiency of solar panels
There is another disadvantage of silicon, which is not as significant as the cost, but which must also be dealt with. The fact is that silicon reflects light very strongly, and because of this, the element produces less electricity.
In order to reduce such losses, photovoltaic cells are coated with a special anti-reflective coating. In addition to such a layer, it is necessary to use a protective layer, which will allow the element to be more durable and resist not only rain and dust, but even falling branches of small size. When installed on the roof of the house, this is very relevant.
Despite the general satisfaction with the technology and the constant struggle to improve performance, modern solar panels still have a lot to strive for. Right now, there are mass-produced panels that recycle up to 20 percent of the light that hits them. But there are more advanced panels that are still being “fine-tuned” – they can recycle up to 40 percent of light.