Fluorene-Carbazole Dendrimers: Synthesis, Thermal, Photophysical and Electroluminescent Device Properties



Novel hole-transporting dendrimeric molecules containing dioctylfluorene, spirobi(fluorene) and spiro(cylododecane-fluorene) as the core unit and different numbers of carbazole and thiophene moieties as the peripheral groups are synthesized. All the dendrimers are characterized by 1H NMR, 13C NMR, FTIR, UV–vis, PL spectroscopy, and MALDI-TOF. They are thermally stable with high glass transition and decomposition temperatures and exhibit chemically reversible redox processes. They are used as the hole-transporting layer (HTL) material for multilayer organic light emitting diodes (OLEDs) with a low turn-on voltage of around 2.5 V and a bright green emission with a maximum luminance of around 25400 cd m−2.