As a rule, most solar cells need to catch direct sunlight. Even those that work indoors can only do so much to generate power from artificial light sources. However, British researchers have found a clever (and decidedly) unusual way to harvest energy while inside: by imitating moths. They've created a graphene-based material that traps electromagnetic waves much like a moth's eye, making it one of the most energy-absorbent substances to date. With the right antennas, it could produce energy from not just sunlight, but any device that emits microwave or radio waves -- your smartphone could help power your smartwatch.
The challenge is getting all the pieces to fall into place. The necessary antennas (which convert electromagnetism into usable electricity) aren't nearly as well-developed as they should be. Still, it's a start toward a future of widespread green power. Besides, it shows that even seeming pests have a few tricks up their sleeves.