I know this is kinda dumb question, im just really curious why
In: Technology
There are two types of solar panels. One is black (monocrystalline) and the other is blue (polycrystalline). The blue ones are less efficient as you suspected, but are easier and cheaper to make.
It doesn’t really matter. Light is characterised by its wavelength, for example visible light has wavelengths in the range of a few hundreds nanometers. Red light is at one edge of the visible range (longest wavelength) while violet is at the other (shortest wavelength), with all other colours in between. The Sun emits light over an even wider range of wavelengths, but with varying intensity (it peaks in the visible range, which is why our eyes evolved to work in that range).
For reasons which are too complicated to explain in an ELI5 post, solar panels can only efficiently use light within a rather narrow wavelength interval which depends on the material the panel is made out of. For silicon solar panels, the most common type, this interval is close to the one where solar emission is at its peak, which is good, however a large part of the solar spectrum goes essentially to waste. So it doesn’t really matter if the panel isn’t black, it still wouldn’t be able to use those extra wavelengths it would pick up.
The thing is that polycrystalline silicon solar panels (the blue ones you’re referring to) are what’s called “1st generation solar panels”. Research-wise, we’re up to the 3rd or even 4th generation according to some. Despite their lower performance, 1st generation panels are still the only ones with some degree of commercial success. Why? Because silicon is dirt cheap, extremely common, non-toxic, an inert and very stable compound and silicon manufacturing is extremely mature because our entire electronic technology is based off it. So basically any marginal improvements cannot compete with the fact that you could just use more cheap p-Si panels to do the same job.
I don’t think this question was answered sufficiently (or correctly) so I will add to it. It certainly is not a dumb question and is actually a huge field of solar panel development.
Firstly, both commenters are quite wrong by saying the blue panels are multicrystalline (MC). It is an understandable mistake though as you see the blue color more often with MC panels these days.
The blue color is from an antireflective coating that is applied to the panels. Thats a little ironic since silicon is naturally black. It looks like this: https://www.letsgosolar.com/wp-content/themes/solar/images/consumer-education-guide/how-are-solar-panels-made/raw_naterial.png
Though it is black, it is also very shiny like a mirror and will reflect away all the light you want to absorb. This is why they add the blue anti-reflective coating to it. Only a little bit of blue is able to bounce off this coating so much more light enters the panel.
More recent panels have better coatings that do *not* reflect blue light leaving the panels black. This black coating is put on all new panels because less reflections mean more power. We do not use MC panels much now because even though they are cheap we have learned how to make Monocrystalline (MONO) panels much cheaper than before and they are more efficient too. So both MC and MONO panels were blue in the past but we don’t make MC any more and we also use a better black coating.
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