Photovoltaic cells which are famously known as PV cells are an important part of solar panels. PV is actually a method through which electric power is generated by using solar energy. These PV cells directly convert solar radiations into DC current with help of some semiconductors installed with these cells. Material that is used to compose these PV cells includes monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium gallium selenide/sulfide. Increasing demand for use of renewable energies has also increased use of PV cell around the world. After hydro power and wind power these cells are counted as third important source for renewable energy. In almost all industries PV solar panels are working for purpose of generating electricity at cheaper rates.
How Photovoltaic solar cells work:
Sun light is composed of photons and different elements that contain radiant with it. This is solar energy which contains different other energies with different wavelengths of solar spectrum. When these radiant from sun moves towards earth and strike to the solar panel and PV cells, it get absorbed here. These cells absorb just protons and reflect all other rays back. Once proton reach to their targeted area then electrons from PV cells started dislodged from their atoms of this cell. These electrons start moving slowly from end towards surface of solar cells which is designed especially for purpose of moving electrons freely.
As we all know that electrons carry negative charge and protons carry positive charge, so while moving these electrons come near to the front surface where protons are absorbed. These two opposite powers attract each other which results in imbalance of two charges from front towards end of PV cells. This continuous movement of these charges in the cell cerates voltage potential and the moment when these two surfaces are connected with each other with help of external load, electricity starts flowing from its positive terminal to negative terminal. This is how photovoltaic solar cell works and generates electricity for us.
PV cells are attached in different combinations with each other to make a module or array. Collection of cell is known as module and collection of modules is known as array of these cells. Modules are designed to supply electricity at a defined voltage, commonly its range is 12 volts. Current that is produced through these modules completely depends on sunlight or protons that strike to its surface. Same like module array is formed; it increases the capacity of voltage that can be carried easily. These arrays produce direct current and can be connected in parallel as well as series electrical arrangement so that required level of voltage can be achieved easily.
If we talk about currently used PV cells in solar systems, then we will found that they use a single junction or interface to create stronger electric field. If single junction PV cell is used then those protons can free or attract the electron towards surface whose energy is either equal to or more than band gap of two surfaces. Many researches has shown that multi-junction cells emphasis more on gallium arsenide which is an important part of PV cell used in solar systems.
To remove these limitations now two or more PVcells are used, more power of electrons can easily cross the gap and move from one junction to another as sunlight hits the surface. This multi-junction arrangement of cells creates higher total conversion efficiency with their ability to convert more solar energy into electricity.
Use of this material makes cells 35% more efficient when they come in direct contact with sunlight. Other materials also play important role in formation and functioning of cell but none of them can compete it.