While no one is exactly sure what the lifespan of a solar cell is, we do know that they degrade over time due to the harmful effects of ultraviolet rays. As a result, you lose efficiency in the panels. Generally, manufacturers will cover a panel against defects for 20-25 years — but after that, it’s a guessing game into how much juice will continue to flow.
Those estimates, however, may soon get a bump higher. Scientists have found a way to increase the lifespan of solar cells by coating them with a material that converts ultraviolet photons into ones of visible light. Essentially, this takes UV rays and stretches them into longer wavelengths, resulting in greater efficiency for the panel and reducing damage to the cells. From the article,
“The researchers have demonstrated through some experiments that the PCM could be made of a liquid, a gel, nanoparticles or a solid. In experiments, the research team added the polymer blue polyfluorene to solar cells and found that it did indeed reduce the damage caused by UV light.”
This is good news — especially for applications like planetary exploration where the use of solar energy to power spacecraft can be exclusive. Of course, back home, it also means your investment will last that much longer.