The photovoltaic effect is the phenomenon discovered by Edmond Bequerel in 1839, which consists of the physical characteristics of some semi-conductive materials that, under the right conditions, allows them to produce electrical energy provided by exposure to solar radiation.
The photovoltaic cell is the element that allows for the conversion of solar energy into electricity. This occurs when electromagnetic energy hits the semi-conductive material of the cell, causing the photons to transfer their energy to the material’s electrons, thereby resulting in the generation of electrical charges that flow towards a conductor opportunely connected to the cell’s positive and negative poles. This process provides an influx of energy in the form of a continuous electrical current.
The first photovoltaic cells made from silica were created by the Bell Corporation in 1954. Unfortunately, high production costs limited their use. It was only in the 1970s that a reevaluation of photovoltaic technologies occurred, due to the development of new industrial methods of manufacturing photovoltaic cells that rendered them more economical and therefore more utilizable in the production of electrical energy in the civilian sector.
Silica is one of the most widespread and commonly found elements on earth. It is also useful in the manufacturing of photovoltaic cells. Silica does not exist in a pure form, but is contained in sand. Silica can be extracted and purified by means of chemical processes, as the photovoltaic industry requires it to have an extremely high level of purity.
There are two primary types of crystalline silica utilized in the production of photovoltaic cells: poly- and mono-. The manufacturing process transforms the ingots of silica (obtained by the fusion of fragments) into wafer-like structures through a cutting phase elemental to the formation of the cell. The photovoltaic cell transforms sunlight into electrical energy, as its constitution is made up of semi-conductive material (silica) in the form of “wafers” of approximately 250µm, with each containing appropriately placed positive and negative poles, similar to those of a diode.
The polycrystalline silica cells have a square-like form with standardized dimensions of 156mm X 156mm. Their principal visual characteristic is their reflexive iridescent surface caused by the casual arrangement of the crystals.