How Everything Works
How Everything Works How Everything Works

Question 1178

Can a photocell ever absorb too much light? If it can, does it explode or simply stop absorbing light? — MR
Since not all of the light power absorbed by a photocell is converted into electric power, a photocell that's exposed to too much light will overheat. High temperatures are disastrous for all semiconductor devices, including computer chips and photocells. If a semiconductor device overheats slightly, the excessive thermal energy will change the electronic properties of the semiconductor layers so that these layers won't behave as they were chemically prepared to do. In an overheated photocell, charge will be allowed to flow backward so that the photocell will become less energy efficient. But if a semiconductor device overheats seriously, the semiconductor layers will change permanently—atoms, molecules, and entire structures will migrate and rearrange, and the device will never work properly again.

By itself, an overheated photocell won't fail dramatically; it will just stop working. If you've overheated it severely, it will remain broken from then on. But if the photocell is part of a larger collection of power generating elements that continues to produce power, that photocell may suddenly consume all of the power from the other elements. In that case, the photocell may explode as its temperature skyrockets.


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