Solar power cells have raced past the key milestone of 30% energy efficiency, after innovations by multiple research groups around the world. The feat makes this a “revolutionary” year, according to one expert, and could accelerate the rollout of solar power. Today’s solar panels use silicon-based cells but are rapidly approaching their maximum conversion of sunlight to electricity of 29%. At the same time, the installation rate of solar power needs to increase tenfold in order to tackle the climate crisis, according to scientists. The breakthrough is adding a layer of perovskite, another semiconductor, on top of the silicon layer....