Solar panels that are 35% efficient may be just a few years away


The average panels used on rooftops and in solar farms have an efficiency of around 22%. This is because silicon only responds to certain wavelengths of light, those that are in the red and yellow part of the electromagnetic spectrum. The longer light waves in the infrared part of the spectrum are too weak to create an electrical current and the shorter light waves in the blue and green part of the spectrum don’t create any electrical current but generate heat, which degrades the efficiency of panels. The maximum theoretical efficiency of a silicon-based solar panel is 30%. A group at the University of Cambridge have come up with a system as described in Nature, of converting the blue and green wavelengths to red with is part of the spectrum that the silicon can pick up. This can increase the maximum efficiency to 35% which is 50% more power than solar panels can currently do. “a photon multiplier film made up of a layer of an organic polymer called pentacene studded with lead selenide quantum dots — small, light emitting clumps of inorganic material. The polymer absorbs blue and green photons and converts them into pairs of excitons. These excitons flow to the quantum dots, which absorb them and emit lower energy red or infrared photons.” Now this technology exists we wait until it can be cheaply manufactured.


 

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