The silicon solar cells that currently dominate the world market suffer from three fundamental limitations. A promising new way of making high-efficiency solar cells, using perovskites instead of silicon, could address all three at once and supercharge the production of electricity from sunlight. The first major limitation of silicon photovoltaic (PV) cells is that they are made from a material that is rarely found in nature in the pure, elemental form needed. While there is no shortage of silicon in the form of silicon dioxide (beach sand), it takes tremendous amounts of energy to get rid of the oxygen attached to it. Typically, manufacturers melt silicon dioxide at 1500 to 2000 degrees Celsius in an electrode arc furnace. The energy needed to run such furnaces sets a fundamental lower limit on the production cost of silicon PV cells and also adds to the emissions of greenhouse gases from their manufacture. Perovskites (a wide-ranging class of materials in which organic molecules, made mostly of carbon and hydrogen, bind with a metal such as lead and a halogen such as chlorine in a three-dimensional crystal lattice) can be made much more cheaply and with fewer emissions. Manufacturers can mix up batches of liquid solutions and then deposit the perovskites as thin films on surfaces of virtually any shape, no furnace needed. The film itself weighs very little.