04-10-2017, 11:21 AM
A photovoltaic cell is a specialized semiconductor diode that converts visible light into direct current (DC). Some photovoltaic cells can also convert infrared (IR) or ultraviolet (UV) radiation into direct current. Photovoltaic cells are an integral part of solar-electric energy systems, which are increasingly important as alternative sources of electrical energy.
The first photovoltaic cells were made of combined silicon, or doped, with other elements to affect the behavior of electrons or holes (absences of electrons inside the atoms). Other materials, such as indium copper diselenide (CIS), cadmium telluride (CdTe) and gallium arsenide (GaAs), have been developed for use in PV cells. There are two basic types of semiconductor material, called positive (or type P) and negative (or type N). In a photovoltaic cell, flat pieces of these materials are placed together, and the physical boundary between them is called the P-N junction. The device is constructed in such a way that the bond may be exposed to visible, IR or UV light. When such radiation hits the P-N junction, a voltage difference occurs between the P and N type materials. The electrodes connected to the semiconductor layers allow the current to be drawn from the device.
Large sets of photovoltaic cells can be connected together to form solar modules, matrices or panels. The use of photovoltaic cells and batteries for the generation of usable electric energy is known as photovoltaic. One of the main advantages of photovoltaics is the fact that it is not polluting, requiring only real estate (and a reasonably sunny climate) to work. Another advantage is the fact that solar energy is unlimited. Once a photovoltaic system has been installed, it can provide essentially no cost energy for years, and with minimal maintenance.
The first photovoltaic cells were made of combined silicon, or doped, with other elements to affect the behavior of electrons or holes (absences of electrons inside the atoms). Other materials, such as indium copper diselenide (CIS), cadmium telluride (CdTe) and gallium arsenide (GaAs), have been developed for use in PV cells. There are two basic types of semiconductor material, called positive (or type P) and negative (or type N). In a photovoltaic cell, flat pieces of these materials are placed together, and the physical boundary between them is called the P-N junction. The device is constructed in such a way that the bond may be exposed to visible, IR or UV light. When such radiation hits the P-N junction, a voltage difference occurs between the P and N type materials. The electrodes connected to the semiconductor layers allow the current to be drawn from the device.
Large sets of photovoltaic cells can be connected together to form solar modules, matrices or panels. The use of photovoltaic cells and batteries for the generation of usable electric energy is known as photovoltaic. One of the main advantages of photovoltaics is the fact that it is not polluting, requiring only real estate (and a reasonably sunny climate) to work. Another advantage is the fact that solar energy is unlimited. Once a photovoltaic system has been installed, it can provide essentially no cost energy for years, and with minimal maintenance.