Simultaneous Thermally Stimulated Delayed Phosphorescence (TSDP) and Thermally Activated Delayed Fluorescence (TADF) in a Two-Coordinated Au(I) Bimetallic Complex Featuring a Tandem Carbene Structure.

A bimetallic, two-coordinated carbene-metal-amine (cMa) Au(I) complex featuring a twisted tandem carbene structure (NHC-Au-NHC-Au-carbazolyl) was synthesized. The molecular structure in single crystals revealed a large dihedral angle between the two carbene ligands, while the bridged carbene NHC and carbazolyl (Cz) ligands were coplanar. A bluish green thermally stimulated delayed phosphorescence (TSDP) was observed in crystals with an emission lifetime over 70 μs, which can be attributed to the spin allowed diabatic population of a high-lying emissive triplet state from the LE characterized low-lying ones.