Episode 3: Copper-iodide hybrid material enables deep blue LEDs

In this podcast episode, MRS Bulletin’s Sophia Chen interviews Jing Li at Rutgers University and Kun Zhu at the Max Planck Institute of Microstructure Physics about the material and a solution-based manufacturing process they introduced to produce deep blue light-emitting diodes (LEDs). The LEDs emit light at 460 nm. The LED consists of several layers, beginning with an indium tin oxide (ITO) substrate that serves as an electrode. Above the ITO is a single molecular layer of the polymer, polymethyl methacrylate. An 85-nm layer of the emissive hybrid copper iodide material goes on top of the polymer, which forms hydrogen bonds with the emissive material. These hydrogen bonds serve two purposes. They make the hybrid material less reactive, which improves the LED’s stability. The hydrogen bonds also help introduce electrons and holes in balanced numbers into the emissive material, allowing it to emit light more efficiently. This dual hydrogen bonding approach is unique to the researchers’ process. This work was published in Nature.