During daylight hours, streams of solar energy enter the planet's surface. Scientists and engineers have long figured out how to use it. Solar panels can convert the energy of the daylight. Their effectiveness is still far from ideal, but over time it will increase thanks to the work of specialists.
The work of a solar cell is based on the physical properties of semiconductor cells. The photons of light knock out electrons from the outer radius of the atoms. In this case, a significant number of free electrons are formed. If you now close the circuit, an electric current will flow through it. However, it is too small to be limited to the use of one or two photocells.
Typically, individual components are combined into a system to form a battery. Several such batteries are used to form modules. The more solar cells are connected together, the higher the efficiency of the technical system. The position of the solar battery relative to the luminous flux is also important. The amount of energy directly depends on the angle at which the sun's rays fall on the photocells.
One of the main performance characteristics of a solar cell is the coefficient of performance (COP). It is defined as the result of dividing the power of the received energy by the power of the luminous flux that falls on the working surface of the battery. To date, the efficiency of solar cells used in practice ranges from 10 to 25 percent.
In the fall of 2013, there were reports in the press that German engineers managed to create an experimental photocell, the efficiency of which is approaching 45%. To achieve such incredible performance for a standard solar array, the designers had to use a four-story photocell layout. This increased the total number of useful semiconductor junctions.
Experts have calculated that in the future it will be possible to achieve higher efficiency rates, up to 85%. What is the reason for the current battery lag behind the design characteristics? The difference between real figures and theoretically possible indicators is explained by the properties of the materials used to make batteries. Panels are usually made of silicon, which can only absorb infrared radiation. But the energy of ultraviolet rays is almost never used.
One of the ways to improve the efficiency of solar cells is the use of multilayer structures. Such a module includes several thin layers made of dissimilar materials. In this case, the substances are selected so that the layers are matched from the point of view of energy absorption. In theory, such multi-layer "cakes" can provide efficiency up to almost 90%.
Another promising direction of development is the use of panels made of silicon monocrystals. Unfortunately, this material is still much more expensive than polycrystalline analogs. Thus, in order to improve the efficiency of solar cells, it is necessary to make the design more expensive, which increases the payback period.