Light-emitting diodes (LEDs) are so ubiquitous that it's easy to forget just how much society relies on these underappreciated technological wonders. Yet, the history of the LED goes back further than ...

We developed a hybrid copper–iodide compound called CuI(Hda). It emits deep-blue light at about 449 nanometres and has an almost-perfect photoluminescence quantum yield — a measure of emission ...