Why are solar panels black at the back and why do they have a clear plastic cover?

Please help


thankyou very much!Why are solar panels black at the back and why do they have a clear plastic cover?
The clear plastic cover allows light rays to go through. The black on the back absorbs all the light and turns it into heat. Here water or air or oil takes the heat and circulates it to where it is to be used. Light rays can be reflected, transmitted or absorbed. Clear transmits them. Black does not reflect any of them, so they are absorbed. You may have noticed that black clothing is warmer in the sun.Why are solar panels black at the back and why do they have a clear plastic cover?
Clear plastic covers permit almost all light photons to enter the panel but resists the loss of infrared (heat) photons like a greenhouse used to grow flowers and vegetables (or a car parked in the sun!). Black is the absence of all color because the black pigment has absorbed almost all of the light photons of solar rays regardless of wavelength, allowing very little light energy to reflect back through the clear plastic cover. The black material heats up from the incident photons and emits infrared photons that can not easily escape through the clear plastic cover. Using a clear plastic cover and a black photon absorber increases efficiency of the unit.
I'm not sure I completely agree with the others here, but I don't know the specifics of photovoltaic cell (PV) manufacturing, but I'll explain my reasoning:





Your PV cell works by a semiconductor film that turns light energy into electrical energy. The window on the front, either plastic or glass, is to protect the delicate semiconductor, while allowing light to pass through. The crystal or material you see under the glass or plastic is the semiconductor surface, and it is dark because it is absorbing photons and turning them into electricity. It is very delicate and needs to be protected. The back side of the semiconductor needs to be protected as well, but it doesn't need to be anything that passes light through.





I think they just use some sort of material that can be cheaply painted on the back to protect the back, and it happens to be black. You could paint the back of your PV cells pink and they'd still function perfectly. In other words, I think the color on the back is irrelevant and has nothing to do with the absorption of photos in the semiconductor.; rather it has to do with the available protective coating. I know that what you are seeing on the back is not the bare silicon PV material. Look at the back of a mirror--they usually have a black or gray protective coating as well--it's just to protect the reflective surface--has nothing to do with the mirror coating--without it, the back of a mirror would be silver as well. Black does radiate heat a little better than white, so it may be black to keep the PV cells cool, but that plays a minor role in its function. I just don't think it has anything to do with collecting heat or photons. Collecting photons is the job of the PV material, which is only visible through the window on the top.





The PV cell does not use infrared heat to make electricity! It's not a heat engine! If anything, heat might be bad for it.
bcoz black is a good conductor of heat %26amp; plastic cover doesnot allow to get back heat stored in it . due to this process solar panels get charged
so light/heat can get in and cannot get out the back side