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Future LEDs could be based on lead halide perovskites. A breakthrough in preparing device-compatible solids composed of nanoscale perovskite crystals overcomes a long-standing hurdle in making blue perovskite LEDs.
Light-emitting diodes (LEDs) now serve as energy-efficient replacements for incandescent light bulbs, and provide high colour saturation and brightness in display technologies. Nevertheless, the search for even more efficient devices continues, and LEDs based on a class of semiconductor called lead halide perovskites show particular promise1. The development of stable blue-emitting perovskite LEDs has long been hampered by challenges in the materials chemistry of these semiconductors. Writing in Nature, Jiang et al.2 report a remarkably simple process that provides stable light-emitting layers of nanosize perovskite crystals. The authors used these films to make blue-emitting LEDs that convert charge carriers into photons with record-breaking efficiency, a key advance in the development of perovskite-based lighting and displays.