Can a solar cell be "overwhelmed" with light?

[Themohawkninja]

Aside from the inevitable temperature issue, is it possible for there to be so much optical light hitting a solar cell that it just overwhelms the photosensitive material, and "burns out" the cell?

I ask this, because in the article that was recently posted about a black hole powered starship, it mentions the use of gammavoltaic cells to makes use of any residual radiation from the black hole. Since such technology is being researched, I was wondering just how great (or terrible) of an idea it would be to place large gammavoltaic cells in the path of a quasar's jet (assuming it's also somehow possible to shield it from the heat) to feed off of the insane amount of gamma radiation being outputted as a source of energy for some far distant future human civilization.

[Ravenchant]

Keeping the electronics the panels would produce electricity for from frying would be a far bigger problem than any damage to semiconductive materials within.

Edited December 25, 2013 by Ravenchant
spelling -.-

[lajoswinkler]

Yes, it can.

[K^2]

It shouldn't. It can, but it shouldn't. Almost any cell you can draw too much current from, causing it to fail the way any other semiconductor device would from overheating. However, if you regulate the output current or disconnect the cell all together, this won't happen. So we can talk about failure modes of a disconnected cell.

Even if the cell isn't connected, as long as there is light flux, there will be internal currents. If you look at an equivalent diagram, you'll see that it contains a resistor and a diode connecting the two sides of a photovoltaic cell. In principle, if current through these "elements" gets too high, the cell can also burn out without being connected to anything. However, a typical cell will saturate before this happens. So if this is a concern, you can design a cell not to fail in such a way.

Of course, that's a conventional PN junction photovoltaic cell. I don't know what they have in mind for a gamma cell. If it's just a scintillator with a conventional cell, all the same logic applies. If it's something more sophisticated, I don't know.

[WestAir]

It shouldn't. It can, but it shouldn't. Almost any cell you can draw too much current from, causing it to fail the way any other semiconductor device would from overheating. However, if you regulate the output current or disconnect the cell all together, this won't happen. So we can talk about failure modes of a disconnected cell.

Even if the cell isn't connected, as long as there is light flux, there will be internal currents. If you look at an equivalent diagram, you'll see that it contains a resistor and a diode connecting the two sides of a photovoltaic cell. In principle, if current through these "elements" gets too high, the cell can also burn out without being connected to anything. However, a typical cell will saturate before this happens. So if this is a concern, you can design a cell not to fail in such a way.

Of course, that's a conventional PN junction photovoltaic cell. I don't know what they have in mind for a gamma cell. If it's just a scintillator with a conventional cell, all the same logic applies. If it's something more sophisticated, I don't know.

I'm of the honest opinion that the educational system in America is so bad because K^2 used it all.

Every last bit of it.

[VirtualCLD]

Even though this topic is closer to my area of expertise, all I can do is ditto what K^2 said. Even disconnected or debiased photovoltaic devices can be overwhelmed by photon flux, but if the structure (be it PN Junction, Barrier Junction, etc...) is designed to saturate at a point, you can prevent internal currents from burning out the device. I have seen cheap CMOS camera sensors get damaged when the sun entered their field of view, but I have seen more expensive sensors that weren't affected by it at all. I have not, personally, heard if photovoltaic devices get burned out, but that doesn't mean it has never happened.

[TheSandDuna]

Since photons are a form of energy, when that energy is more than what is required for electrons to jump into the conduction band and start flowing (as is the case in PN juntion solar cells), the energy is wasted for current generation purposes. Having too much energy applied all at once will cause that photon to be lost as heat mainly. So even though you have shielded the PV panel from the heat, applying too much high frequency (and thus high energy) light will overheat your cell by itself. At least that is what my knowledge of solar cells would lead me to believe.

But like K^2 and VirtualCLD said, an ideal cell is basically a diode capable of passing a constant current, so if you were able to cool your solar cell you would reach a maximum current of Isc by connecting the terminals or a maximum voltage Voc by simply applying light.

A good site for studying PV cells is this one.

Edited January 31, 2014 by TheSandDuna

[Nuke]

im pretty sure you can use them in such intense light that they would fail to ablation of material from the surface. but so long as you limit the current (and you can just use a resistor for that) they shouldnt burn out due to pushing too much current through them. a panel is really an array of smaller units, use a row of cells in series till you get a voltage that you want, then connect a bunch of rows in parallel till you get the current you want. then just keep the sun on it. put the output through a switch mode supply and onto the mains.

Edited January 31, 2014 by Nuke

[Idobox]

If you shine ionizing radiation to solar cell, you could also cause damage.

High energy photons like X-Ray and gamma can ionize several atoms in a row, or even knock some atoms out of the lattice. It can be an issue on sensitive electronics, but I'm not sure something like a PV cell could suffer significantly from it.

[Nuke]

i dont think pv cells are as sensitive. i can understand where you have dopped traces a couple atoms wide that could really be damaged by a lattice shift. but the structure of a photovoltaic cell is very simple in comparison. you might get some localized degradation manifested as a slight drop in power output. you probibly get more damage from space dust and solar wind than you do from radiation.