While impressive, the last few decades of human achievement in photovoltaics pale in comparison to nature’s equivalent technology: photosynthesis. Just look at the numbers—every year photosynthesis produces about 3,000 exajoules (EJ) of chemical energy, or 7 x 1017 kilocalories, which equates to about half the total energy stored in the world’s petroleum reserves (and approximately the average daily caloric intake of eating champ Joey Chestnut). Compare this to the 0.1 EJ of electrical energy produced annually by man-made photovoltaics. Closing this gap is the key to a sustainable energy future, and unlike nature we don’t have the luxury of waiting billions of years to get there.