Stable hole-transporting molecular glasses based on complicated 9,9-diarylfluorenes (CDAFs)

A series of complicated 9,9-diarylfluorenes (CDAFs) with highly thermal and morphological stability, end-capped oligothiophenes (T)n(PF)m (n = 1–3, m = 2) and triphenylamines TPA(PF)m (m = 1–3), were synthesized via BF3·Et2O-mediated Friedel–Crafts reaction. TPA(PF)2 with bulky 9-phenylfluorene moieties (PFMs) as a morphological stabilizer possesses excellently amorphous solid state with a glass transition temperature (Tg) up to 140 °C and no Tg was observed for TPA(PF)3 with high decomposition temperature up to 499 °C. Preliminary characterizations of typical double-layer devices with the configuration of ITO/TPA(PF)3/AlQ3/Mg:Ag show luminance efficiency of ca. 2.25 cd/A at 100 cd/m2 with a maximum brightness of ca. 8300 cd/m2.