Solar panels can produce “free” energy for a very long time. However, there’s one problem: The panels collect dust, and that reduces their efficiency. Scientists have now developed a “shaky plastic” that oscillates when exposed to sunlight. This plastic film can be used as a coating on photovoltaic panels in dusty locations. The scientists used light-sensitive molecules that bend and stretch under the influence of light. So the new material needs nothing more than natural daylight to get it moving.