PV Gap

Louis Said:

What is the environmental impact of photovoltaic semiconductor fabrication?

We Answered:

Not only the cost in terms of money but also the cost in terms of energy

Wendy Said:

Will a photovoltaic cell convert electricity from alpha, beta or gama radiation?

We Answered:

The short answer is no. The key is what the material in the cell is responsive to, and most of these materials will be easily penetrated by high energy photons, or simply attenuate the photon completely, not "convert" it into electrical energy.

While there are thermovoltaic cells, these utilize EM from the non-ionizing side of the visible light portion of the EM spectrum, specifically infrared. A source of this infrared can be the the heat of decay of radioisotope, but this is not exactly what you are talking about.

Javier Said:

Can anyone tell me the best three elements to produce photovoltaic effect?

We Answered:

The best objects would be ones where the energy to release an electron from the atom is smallest thats the work function of the material

Most metals have a low workfunction so they would be suitable

I will look up more details on actual work functions of actual metals and other substances to see if i can give you element names

http://en.wikipedia.org/wiki/Work_functi…

you pick a metal you can find then you look up the element on the table the elements with the smallest workfunction are radio active so not suitable use non radioctive substances please..

the one they use commercially is http://www.ladyada.net/learn/sensors/cds… its Cadmium sulfide it is used for a photo resister the photons release the electrons and they begin to conduct lowering the resistance.

you have to calculate the energy required too because different eV work functions require different energy levels so would require different frequency of photons


thats it good luck

Barry Said:

What is usually connected to photovoltaic cells?

We Answered:

a) to whatever is connected to dra some current from it.
b) possibly, but at the cost of current.
c) anything from nought upwards. depends on the area exposed to the sunlight.
d) very close, but not a great idea. the wavelength spectrum of ordinary globes is much narrower and more selective than sunlight, so you're likely to make use of only a fraction of the efficiency of your PV cell.

Darren Said:

What is the service life for photovoltaic cells?

We Answered:

Depends upon what you'd consider "service life" for your particular application -- would a 25% loss in power output cause you to call the cell toast? While warranties exist, as noted in post #1, it's like a NiMH cell ... great at the beginning, but after 300~500 cycles, most warranties only guarantee 60~65% of the original cell capacity.

Power loss over time is all over the map depending upon the materials used. As an example, this link

http://www.osti.gov/bridge/servlets/purl…

demonstrates that the use of different top film materials in the cell construction made a HUGE difference in power output. Looks like Tefzel, while good in other respects, creates far too much opacity (kinda critical for a solar cell) over time due to exposure, and really killed the power output in this particular accelerated test.
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