Quantum dot LEDs go cadmium-free

Coming soon to a television near you: next generation, quantum dot light-emitting diodes (QD-LEDs) that will illuminate displays without using cadmium, a toxic metal. Researchers led by Eunjoo Jang of Samsung Electronics report QD-LEDs made with quantum dots that feature an indium phosphide core surrounded by a thick inner shell of zinc selenide and a thin outer shell of zinc sulfide. The core’s size determines what color light it emits. This InP/ZnSe/ZnS structure has been reported for quantum dots before, but defects in those materials resulted in decreased performance.