1,5-Disila-s-indacene-based emitters: a molecular design towards efficient blue OLEDs†

We designed three 1,5-dihydro-1,5-disila-s-indacene-based emitters with blue/deep-blue fluorescence emissions by introducing trifluoromethyl phenyl units into the π-extended bisilole fluorophores. When these silole derivatives were applied in electroluminescent devices, the 2, 3, 6, and 7 tetra-substituted 1,5-disila-s-indacene-based device gave the hitherto highest maximum external quantum efficiency (5.43%) for a silole-based blue OLED.