Sky‐Blue Triplet Emitters with Cyclometalated Imidazopyrazine‐Based NHC‐Ligands and Aromatic Bulky Acetylacetonates

Platinum(II) complexes with an N ‐heterocyclic carbene and a cyclometalating phenyl ligand (C^C*) are excellent candidates as efficient blue triplet emitters for OLED applications. The electronic and photophysical properties of these complexes can be fine‐tuned with the objective to increase the quantum yields and lower the phosphorescence decay times. We found that platinum complexes with an imidazopyrazine C^C* ligand and bulky acetylacetonates are sky‐blue triplet emitters, characterised by an almost unitary quantum yield and short phosphorescence decay times.