Highly Luminescent Cu^I Complexes for Light‐Emitting Electrochemical Cells

Highly luminescent CuI complexes with one phenanthroline and one (bis[2-(diphenylphosphino)phenyl]ether) ligand show an emission quantum yield of up to 28 % upon deactivation of the metal-to-ligand charge-transfer excited states; their X-ray crystal structure shows a distorted tetrahedral geometry (see figure and inside cover). One of these compounds is used as an active material in a light-emitting electrochemical cell; it exhibits an efficiency similar to that of RuII-type complexes.