When Sam Goldman was a Peace Corps volunteer in the West African nation of Benin in 2004, he saw a boy get seriously injured in a kerosene-lamp fire. So later, while attending Stanford’s design school, Goldman—working with fellow student Ned Tozun—decided to create something that could better serve the more than 1 billion people around the world who lack electricity. That school project grew into San Francisco–based company D.light, which, after coming up with several less-affordable iterations, in 2015 introduced a solar-powered lantern that’s safe, reliable, and, most important, inexpensive. The A1 is more than twice as bright as kerosene lamps and can withstand years of daily use. It costs just $5—the amount a family would typically spend on kerosene in a three-week period. "Our goal," says Goldman, "was a light that was essentially no-risk in a world that is full of risks for our customers."