Rui Wang

Perovskites have been a major focus of photovoltaic research in recent years because of their intriguing optoelectronic performance, but the poor stability of these synthetic materials has thwarted their commercialization. They quickly fall apart when out in the world. Rui Wang, 29, found that adding caffeine and its derivatives—an idea that occurred to him while drinking coffee—could improve the stability of perovskites “from several hours to almost five years.” His next challenge? Making a perovskite solar cell that will last for decades.