Synthesis and functional properties of oligofluorenyl-dibenzothiophene S,S′-dioxides end-capped by diphenylamine moieties

2,7- and 3,6-Bis [7-diphenylamino-9,9-di(n-butyl) fluorene-2-yl]dibenzo-thiophene S,S′-dioxides, 2,7-OF(2)BTO-NPh and 3,6-OF(2)BTO-NPh have been synthesized by a convergent approach using palladium-catalyzed Suzuki cross-coupling or copper-catalyzed Buchwald's amination as the key reactions. The functional properties including thermal stabilities, optical properties, electrochemical properties of these two oligomers, as well as the performance of 2,7-OF(2)BTO-NPh-based OLEDs have been investigated and discussed. With a simple three-layer structure of ITO/3,6-OF(2)BTO-NPh (40 nm)/F-TBB (15 nm)/Alq3 (20 nm)/LiF (1 nm)/Al (75 nm), the luminance efficiency of 3,6-OF(2)BTO-NPh-based OLEDs can also reach up to 0.42 cd/A with a maximum brightness of 1620 cd/m².