A solar cell (or a "photovoltaic" cell) is a device that converts photons from the sun (solar light) into electricity.
In general, a solar cell that includes both solar and nonsolar sources of light (such as photons from incandescent bulbs) is termed a photovoltaic cell.
Fundamentally, the device needs to fulfill only two functions: photogeneration of charge carriers (electrons and holes) in a light-absorbing material, and separation of the charge carriers to a conductive contact that will transmit the electricity.
This conversion is called the photovoltaic effect, and the field of research related to solar cells is known as photovoltaics.
Solar cells have many applications.
Historically solar cells have been used in situations where electrical power from the grid is unavailable, such as in remote area power systems, Earth orbiting satellites, consumer systems, e.g. handheld calculators or wrist watches, remote radio-telephones and water pumping applications.
Solar cells are regarded as one of the key technologies towards a sustainable energy supply.
A new twist on an old solar cell design sends light ricocheting through layers of microscopic spheres, increasing its electricity-generating potential by 26 percent.
By engineering alternating layers of nanometer and micrometer particles, a team of engineers from the University of Minnesota has improved the efficiency of a type of solar cell by as much as 26 percent. These cells, known as dye-sensitized solar cells (DSSC), are made of titanium dioxide (TiO2), a photosensitive material that is less expensive than the more traditional silicon solar cells, which are rapidly approaching the theoretical limit of their efficiency. Current DSSC designs, however, are only about 10 percent efficient.
One reason for this low efficiency is that light from the infrared portion of the spectrum is not easily absorbed in the solar cell. The new layered design, as described in the AIP's Journal of Renewable and Sustainable Energy, increases the path of the light through the solar cell and converts more of the electromagnetic spectrum into electricity. The cells consist of micrometer-scale spheres with nanometer pores sandwiched between layers of nanoscale particles. The spheres, which are made of TiO2, act like tightly packed bumpers on a pinball machine, causing photons to bounce around before eventually making their way through the cell.
Each time the photon interacts with one of the spheres, a small charge is produced. The interfaces between the layers also help enhance the efficiency by acting like mirrors and keeping the light inside the solar cell where it can be converted to electricity. This strategy to increase light-harvesting efficiency can be easily integrated into current commercial DSSCs.
credit for:http://www.sciencedaily.com/releases/2011/07/110729175554.htm
In general, a solar cell that includes both solar and nonsolar sources of light (such as photons from incandescent bulbs) is termed a photovoltaic cell.
Fundamentally, the device needs to fulfill only two functions: photogeneration of charge carriers (electrons and holes) in a light-absorbing material, and separation of the charge carriers to a conductive contact that will transmit the electricity.
This conversion is called the photovoltaic effect, and the field of research related to solar cells is known as photovoltaics.
Solar cells have many applications.
Historically solar cells have been used in situations where electrical power from the grid is unavailable, such as in remote area power systems, Earth orbiting satellites, consumer systems, e.g. handheld calculators or wrist watches, remote radio-telephones and water pumping applications.
Solar cells are regarded as one of the key technologies towards a sustainable energy supply.
A new twist on an old solar cell design sends light ricocheting through layers of microscopic spheres, increasing its electricity-generating potential by 26 percent.
By engineering alternating layers of nanometer and micrometer particles, a team of engineers from the University of Minnesota has improved the efficiency of a type of solar cell by as much as 26 percent. These cells, known as dye-sensitized solar cells (DSSC), are made of titanium dioxide (TiO2), a photosensitive material that is less expensive than the more traditional silicon solar cells, which are rapidly approaching the theoretical limit of their efficiency. Current DSSC designs, however, are only about 10 percent efficient.
One reason for this low efficiency is that light from the infrared portion of the spectrum is not easily absorbed in the solar cell. The new layered design, as described in the AIP's Journal of Renewable and Sustainable Energy, increases the path of the light through the solar cell and converts more of the electromagnetic spectrum into electricity. The cells consist of micrometer-scale spheres with nanometer pores sandwiched between layers of nanoscale particles. The spheres, which are made of TiO2, act like tightly packed bumpers on a pinball machine, causing photons to bounce around before eventually making their way through the cell.
Each time the photon interacts with one of the spheres, a small charge is produced. The interfaces between the layers also help enhance the efficiency by acting like mirrors and keeping the light inside the solar cell where it can be converted to electricity. This strategy to increase light-harvesting efficiency can be easily integrated into current commercial DSSCs.
credit for:http://www.sciencedaily.com/releases/2011/07/110729175554.htm
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