Deep-Blue Electroluminescence from Phosphine-Stabilized Au 3 Triangles and Au 3 Ag Pyramids.

The optoelectronic applications of clusters emerged rapidly. Cluster light-emitting diodes (CLED) as representative hold promise as a new generation of displays and lightings. However, as one of the main challenges in electroluminescence (EL) field, until present, no deep-blue CLEDs were reported, due to the strict requirements on excited-state characteristics of clusters. Herein, two phosphine-stabilized Au 3 triangle and Au 3 Ag pyramid named [O(Audppy) 3 ]BF 4 and [O(Audppy) 3 Ag](BF 4 ) 2 were chosen to demonstrate efficient deep-blue CLEDs. The ligand-incorporated charge transfer transitions of the clusters contribute to both singlet and triplet excited states of the clusters, giving rise to phosphorescence at 460 nm and EL emissions at 436 nm. Based on device engineering, the maximum luminescence beyond 8000 nits and the chromatic coordinates with y <0.1 in deep-blue region verify the competence of CLEDs for high-resolution displays.