Bennett McIntosh for the Office of the Dean for Research at Princeton University analyzes the future of light technologies in this feature article. One hundred years ago, Italian chemist Giacomo Ciamician predicted a future society that would run on sunlight.

Kim Kisslinger, seen here with a focused-ion beam instrument, reduced the InGaN samples to a thickness of just 20 nanometers to prepare them for electron microscopy. From the high-resolution glow of flat screen televisions to light bulbs that last for years, light-emitting diodes (LEDs) continue to transform technology. The celebrated efficiency and versatility of LEDs -- and other solid-state technologies including laser diodes and solar photovoltaics -- make them increasingly popular. Their full potential, however, remains untapped, in part because the semiconductor allo...