Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: scientizscht on 28/01/2020 00:21:01

Title: Where do the electrons come from in solar panels?
Post by: scientizscht on 28/01/2020 00:21:01

Hello

In solar panels, light detaches electrons in silica.

Under what voltage do these electrons move and what happens when all electrons have left?

Title: Re: Where do the electrons come from in solar panels?
Post by: evan_au on 28/01/2020 10:43:17

Quote from: scientizscht

Under what voltage do these electrons move

The electron initially moves because of the energy of the photon striking it
- The light kicks the electron into the conduction band, leaving behind a "hole" (the absence of an electron)
- The electron and the hole move towards opposite ends of the solar cell under the influence of the (approximately) 0.7 volts of electricity across the P-N junction of a silicon solar cell (other solar cell materials do exist, with different voltages)
- The electron flows into a copper wire, at the negative terminal
- The hole accepts an electron from the copper wire, at the positive terminal
- The electrons move around the copper circuit to do useful work (like charge a battery)
See: https://en.wikipedia.org/wiki/Theory_of_solar_cells

Title: Re: Where do the electrons come from in solar panels?
Post by: alancalverd on 28/01/2020 11:22:28

….and then return to the P side of the cell!