Archive for April 1st, 2011

1 April

What Is Solar Cell (1)?


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Due to popular demands/requests, I am going to present a series of discussions on solar cell .  A solar cell is also known as photovoltaic cell or photoelectric cell that converts the sunlight/light energy directly into electricity by the photovoltaic effect (the creation of a voltage or a corresponding electric current in a material upon exposure to light).   click below:


In the photovoltaic effect, the generated electrons are transferred between different bands (i.e. from the valence to conduction bands) within the material, resulting in the buildup of a voltage between two electrodes;this  effect was first observed by Alexandre-Edmond Becquerel in 1839.

Photovoltaic cells are simply cells whose light source is not necessarily of sunlight whereas solar cells are cells whose light source is that of sunlight. When  solar cells are electrically connected and encapsulated as a module to make solar modules or solar panels, solar power/energy is generated from these solar modules/panels.  Solar or photovoltaic modules usually have a sheet of glass on the front (sun up) side, allowing light to pass while protecting the semiconductor wafers from abrasion and impact due to rain, hail, debris, etc. Most of the solar cells of the solar panels on the market now a days are made of either monocrystalline silicon or polycrystalline silicon.  Monocrystalline solar cell (darker/black) is more expensive and have higher efficiency than that of polycrystalline silicon.

A solar cell made from a monocrystalline silicon wafer (Source:Wikimedia Commons)

Polycrystalline photovoltaic cells laminated to backing material in a module (Source: Wikimedia Commons)

Modules are then interconnected, in series or parallel or both, to create an array with the desired peak DC voltage and current.  Then the solar generated energy/electricity is often fed into the electricity grid using inverter (a device that converts direct current to alternating current);in stand-alone systems, batteries are used to store the energy for future use.  Solar panels may be used to power or                                                                                  charge portable devices.  For those of you who are thinking of projects or demonstrations for your students or children, please stay tuned in for my next blog.

~Be well and have a sunny day~

Posted by sunisthefuture-Susan Sun Nunamaker,
Any comments and suggestions are welcomed at

Please also get into the habit of checking at these sites below for more on solar energy topics:

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