High Luminescence Gold(I) and Copper(I) Complexes with a Triplet Excited State for Use in Light-Emitting Diodes



Electroluminescence (EL) from the triplet excited statewould extend the range of EL materials able to be used as the emitting layer of organic EL devices from traditional singlet materials to triplet materials such as transition metal complexes. In the EL spectra reported here for highly luminescent gold(I) and copper(I) complexes, the triplet emission intensity is enhanced, while the singlet emission becomes a weak shoulder. This suggests that EL from the triplet state has a larger quantum efficiency than that from the singlet excited state. The bimolecular reaction between triplet excitons is discussed.