Homoleptic iridium complexes with dibenzothiophene sulfone and triphenylamine groups for orange polymer light-emitting diodes

We have designed and synthesized two new orange light-emitting homoleptic iridium complexes (( p -FSOPyTPA) 3 Ir and ( m -FSOPyTPA) 3 Ir) containing dibenzothiophene sulfone and triphenylamine frameworks. Solution-processed polymer light-emitting devices (PLEDs) are also prepared using these as-synthesized iridium complexes with a single-emission-layer (SEL) structure of ITO/PEDOT:PSS/poly-TPD/EML/TPBI/Ba/Al. Both the iridium complexes exhibited good thermal stability with a T d > 430 °C. Compared to ( p -FSOPyTPA) 3 Ir, ( m -FSOPyTPA) 3 Ir displayed much better thermal, photophyscial and electroluminescent properties owing to the different coordinate positions of dibenzothiophene sulfone. More importantly, the orange-emitting PLEDs based on ( m -FSOPyTPA) 3 Ir exhibited a maximum luminous efficiency (LE) of 4.65 cd/A, a maximum external quantum efficiency (EQE) of 2.03%, and the Commission Internationale de L'Eclairage (CIE) coordinates of (0.54, 0.42), when the iridium complex doped into a matrix of PVK/OXD- 7 with a concentration of 4 wt %. Our preliminary work could provide a promising orange emitters candidate for the development of solution-processable highly efficient white PLEDs. Two novel orange-emitting iridium complexes containing dibenzothiophene sulfone and triphenylamine frameworks exhibited good thermal, photophyscial and electroluminescent properties. • Homoleptic iridium complexes with orange emission are synthesized. • Both iridium complexes contain dibenzothiophene sulfone and triphenylamine units. • The device using ( m -FSOPyTPA) 3 Ir as dopant exhibits a highest LE of 4.65 cd A −1 .