Photovoltaics use the internal photoelectric effect to generate electricity from sunlight. Incoming light which is absorbed by a semiconductor crystal releases electrons from their bonding state. An electric field is then required to conduct them away from the solid state.
Solar cells have an n type layer which can emit electrons (emitter) and a p-type layer which can absorb electrons (base). At the boundary interface between the two layers (p-n junction) an electric field us formed, which separates the light-generated charge carriers. A voltage corresponding to the electric field is produced at the terminal contacts of the cell, meaning that current is able to flow as the contracts are connected to each other.
Many types of solar cell have been developed in laboratories to increase efficiency and reduce costs. Five of these are used commercially today and play the role in the market. The fundamental difference between them is the semiconductor material used and their crystal structure (crystalline or amorphous).
Silicon is the prevailing semiconductor in photovoltaics. Monocrystalline (mono-Si) and multicrystalline (mic-Si) are mainly used. Crystalline silicon solar cells achieve the highest efficiency, however the manufacture of high-purity silicon requires relatively large amounts of energy and brings with it high costs.
Thin-film technology, which requires significantly less material, is therefore used in an endeavour to avoid both of these drawbacks.
First generation photovoltaics technology is based on crystalline silicon. The second generation is based on thin-film technology and the third generation encompasses new technologies with have not yet reached a commercial stage – mainly organic cells.
Classic process of manufacturing starts from Silicon extraction as a raw material, processing and refining it and manufacturing ingots and wafers before moving on to cell and module.
Our role starts from module selection with other components (inverters, cables, DC isolators, mounting systems, lighting and surge protection).