From http://www.solarpowernotes.com
How Do Solar Cells Work ?
Photovoltaic is the other name for Solar cells, photovoltaic cells are responsible for producing energy out of sun light it receives. Photovoltaic or solar cells are made of special materials which are semi-conductors. These semi-conductors produces electricity when sun light falls onto its surface. Solar electric cells are simple cells to use, they do not require any thing but sun light to operate, they are long lasting , reliable and easy to maintain. Normally solar panels life time is twenty five years. This is how solar cells work to produce energy.
how does a solar panel work – and what are there solar cell types.
There are many types of solar cell technologies which are under development, but four of them are most commonly used, these technologies are crystalline silicon, thin films concentrators and thermophotovoltaic solar cell. These cells are integrated to other solar power plant components to make electricity available. Let’s study these technologies in detail.
Crystalline Silicon:
Crystalline silicon cells are quite widely used in most solar power panels. These types of cells contain two layers, positive layer and negative layer just like in most semiconductors. Positive layer exist on the top side whereas negative layer exists on button. Electric field is created with in these layers. Photons from sun light strikes on semiconductors in result electrons are released, electrons are electric charge. This electricity is transferred as direct current (DC) in panel.
There are some cells available which are made from polycrystalline silicon, these type of cells are made of multiple but small in size silicon crystals, these kind of cells are relatively cheaper to be produced but there efficiency is compromised, where as single silicon crystal cells have better performance.
Applications of silicon solar cell
Ordinary silicon cells are smaller in size hence produce small amount of electricity. One silicon cell can be used for powering up calculator or wrist watch. To produce enough energy from these types of cell for lightening up entire home modules of silicon cells are require to be made in which these cells are connected together. These modules are building blocks for solar panel. More and more modules are connected together for increasing solar electric power capacity. Arrays of modules are made for power generation in satellites.
Thin Film
Thin film solar cells are simple, durable lighter and easier to assemble when we compare it with silicon module solar cells. Amorphous is used to build best quality thin film cells.
In these form of solar cells atoms arrangement is not in particular order. It is very efficient type of cell; it can convert over 90% of usable solar energy to electricity when it is exposed to light only by using amorphous silicon thin film cell which is only one micron thick. Thin film cells have advantage of being cost effective, they are required lesser amount semiconductor materials.
Application of Thin Films
These types of cells are not produced individually, but they are developed in modules and then joint together to frames and rest of the solar panel. Thin layers of semiconductors are used to manufacture thin films by using backing materials like plastic or glass. These backing materials are directly coated with anti-reflected materials and protective layers. Thin films are designed to match the shape of backing materials; this enabled these types of cells to be extremely flexible in using in innovative and different shapes.
One can easily understand the working of concentrator cells, they works just as optical lens do. Concept is very much same as in magnifying glass. In concentrator cells light is concentrated using lens to fall on solar cells to produce maximum energy as possible. By using concentrator cells light’s intensity is increase by targeting on certain area, which in result increases electricity production.
Most of concentrator cells produced these days are made up of crystalline silicon material. But there are materials like gallium arsenide and gallium indium phosphide have proven to be much more effective in performance when compare with silicon in solar cells, there are chances for these cells will increase in use in future.
Application of Concentrator cells
Concentrator cells are widely used in high tech industries like space and satellites etc, concentrator cells are reliable cells that’s why these cells used in such sensitive and expensive space operations. These cells produce way more energy even by using low quality and less expensive semiconductors materials comparing other solar electric cells.
A normal concentrator cell is consist of lens which help focusing sun on perfect spot of cell, assembly of solar cell, device to waste of extra heat, wires for connectivity etc. These units are capable of combining with other units of different shapes and sizes to form bigger modules. Concentrator cells best works in direct sunlight, dry climates. Tracking devices must be used with these types of cells so that they can manage to keep their direction towards sun.
Thermophotovoltaics
Thermophotovoltaics cell uses different technology to produce electricity. Thermo- means heat, these cells converts heat into electricity; rest of it works as same as photovoltaic cells which converts light into electricity. The only difference between thermo-photovoltaic and photovoltaic is that thermo photovoltaic cells uses semiconductor which are designed for long wavelength, invisible light like infrared rays released by hot objects. This way of generating electricity is very neat and clean and also simpler to what we experience in power generation using generators, steam turbines etc.
Applications for Thermophotovoltaic Cells
These kinds of cells are very useful as they do not require much of maintenance works. They cannot only convent heat energy from sun into electricity but can also convert heat from any source into electric energy. Heat sources like fuel combustions, combustions of gasses etc. thermophotovoltaic cells like all other types of solar cells do not release any by product which can harm environment, that’s why they are clean sources of energy. Thermophotovoltaic cells can be used in furnaces in future to produce their own electricity, can also be useful in battery charging and power generators.
