16626Views8Replies

Author Options:

Which frequency in the visible spectrum does a photovoltaic cell convert into electricity? Answered

plenty on info out there about how a PV cell does its job but so far i've found nothing on which light frequency is responsible for initiating the process.

Discussions

0
None
MolecularMaestro

Best Answer 9 years ago

Sorry in my previously long winded explanation I forgot to give you the info in terms of frequency like you asked.

Wavelength range = 400-1200 nm
Frequency range = 7.5 x 1014 - 2.5 x 1014 Hz or 750 - 250 THz

Here's the sunlight composition diagram image I mentioned in my previous post from the wikipedia as well.

Solar_Spectrum.png
0
None
robertwoodliff

3 years ago

Thank you for putting this up . Great information .

0
None
MolecularMaestro

9 years ago

Technically, sunlight by itself is composed of a range of frequencies & wavelengths spanning from ~250-2500+nm. So, if you can cover that range with highly efficient conversion (50%) and cheaply produce the materials, you will be incredibly rich and famous. However, covering that range turns out to be pretty cost ineffective. In general, highly ordered crystalline inorganic-based approaches, such as the iconic Silicon-based type you see in mainstream media currently hold the highest conversion efficiencies. Most researchers and engineers working on photovoltaic devices are trying to cover the range of 400-1200 nm in the electromagnetic spectrum using a variety of material approaches (i.e. inorganic crystalline systems, organic polymers, etc.) Pretty sweet stuff. This region encompasses the most energetically-dense portion of the sunlight or in more scientific terms, the highest spectral irradiance portion of sunlight. Wikipedia has posted a nicely illustrated graph of what was previously described at http://en.wikipedia.org/wiki/Sunlight under the Composition section.
If anyone's interested in learning more about the science and chemistry involved, feel free to drop me a message, I'd be glad to hook you up with some sweet resources, links, and people you can talk to.

0
None
VIRON

9 years ago

Silicon is very sensitive to infrared and not very sensitive to blue. Old Selenium cells were more consistently sensitive to visible light I think. Selenium might still be used as a standard for photography light meters. Today there are so many different kinds.

0
None
ShutterBugger

9 years ago

I have heard that it's the red light that gets used in silicon solar cells. They are working on cells that use a wider band of frequencies but so far they are very expensive. ~Bob~

0
None
seandogue

9 years ago

Most of the solar energy that is absorbed (for conversion into electricity) in commonly encountered photovoltaic cells comes from the wavelengths in the range of about 500-700nm.

Basically, that means from blue-green to the red area of the visible spectrum.

If you'd like to read a more detailed description of the underlying physics, See: http://www1.eere.energy.gov/solar/photovoltaics.html and choose "How PV works".

0
None
steveastrouk

9 years ago

Depends on the exact cell type. Mostly the shorter wavelengths. Steve