Wide bandgap iridium complexes varying by their ancillary ligands: Influence on their electroluminescence properties

• Three neutral iridium complexes have been tested as emitters.
• TD-DFT calculations and electrochemical measurements were carried out to support the experimental results.
• UV–vis absorption and photoluminescence spectroscopy of complexes were investigated.
• These emitters belong to a family of complex only scarcely studied.

Three heteroleptic iridium(III) complexes comprising 1-methyl-3-propyl-5-(2,4,5-trifluorophenyl)-1H-1,2,4-triazole (tfpt) as the cyclometalated ligand and varying by their ancillary ligands were examined as triplet emitters for Phosphorescent OLEDs. Interestingly, major differences in device performances were obtained with these three isostructural complexes comprising dibenzoylmethane (dbm), acetylacetone (acac) or pyridine-2-carboxylic acid (pic) as the ancillary ligands. Best OLEDs were fabricated with the dibenzoylmethane-based iridium(III) complex. On the opposite, the picolinate and the acetylacetonate-based complexes gave moderate performances. To complement this work, theoretical calculations were carried out on the three complexes. The newly synthesized complex i.e., Ir(tfpt)(pic) was also characterized by UV–vis absorption and luminescence spectroscopy as well as cyclic voltammetry.

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