Solar cells consist of photovoltaic cells and is a device of semiconductors that works just like diodes. The sun’s rays consist of photons and for the system to work, the photons need to be converted to electrons. Photovoltaics is the name of that specific technology that does just that and it makes use of the photoelectric effect. The photoelectric effect is a phenomenon where electrons emit from a substance where it is illuminated with Electromagnetic radiation of sufficiently high frequency.
When each cell is illuminated by the sun, an electric current occurs. Although it is a very small current and therefore the circuits are connected in series in solar panels. If there is a demand for a stronger current, the cells can be connected parallelly instead of series. There are generally two different types of solar cells, and that is crystalline solar cells and thin film solar cells. In today’s society crystalline solar cells are most frequent mostly because they have a high efficiency. The crystalline solar cells can also be divided into two types, polycrystalline or multicrystalline and monocrystalline.
Monocrystalline cells have the highest efficiency. This means of course that they have the longest life, they are the most expensive and also the most difficult to manufacture. the color of monocrystalline cells are dark blue and sometimes almost black.
Polycrystalline cells are a little less efficient and have a little lower life expectancy but on the other hand, they are cheaper. They are easy to recognize because of the speckled blue color.
At last we have thin film solar cells. They have the absolute lowest efficiency and life expectancy but they are still used by many companies due to its ability to get bent. That feature can be of great advantage in some products.
Each cell is a construction of two layers that consists of semiconductors, where one layer is positively charged and the second layer is negatively charged. When sunlight (photons) hits a cell, some of these photons get absorbed in the negative layer of the cell. When enough photons have been absorbed by the layer, electrons will be released. After that a difference in voltage occurs between the positive and the negative layer, that has the form of one volt. The two layers can then be connected to an external load. After the connection a electric current have occurred that can flor through the circuit.
By: Elon TE2b