Electroluminescence based on a β-diketonate ternary samarium complex

The triplet energy state of the HTH [HTH: 4,4,5,5,6,6,6-heptafluoro-1-(2-thienyl)hexane-1,3-dione] ligand was measured to be 20 400 cm−1, which indicated that Sm(HTH)3phen (phen: 1,10-phenanthroline) is a good complex to produce strong PL intensity and high fluorescence yield. Electroluminescent (EL) devices using the Sm(HTH)3phen complex as the emissive center were fabricated by vapor deposition and spin-coating methods. The relative intensity of the EL spectra changed compared to the photoluminescence (PL) spectrum, which suggested that the luminescence mechanisms of PL and EL have differences. A luminance of 9 cd m−2 and a higher brightness of 21 cd m−2 were obtained from the devices ITO/TPD (40 nm)/Sm(HTH)3phen (50 nm)/PBD (30 nm)/Al (200 nm) and ITO/PVK (40 nm)/PVK∶Sm(HTH)3phen (2.5 wt%, 50 nm)/PBD (30 nm)/Al (200 nm), respectively.