| Abstract
| - Propeller-shaped molecules diphenyldibenzofulvene (1) and (4-methoxyphenyl)phenyldibenzofulvene (2) werenonemissive when dissolved in good solvents but became luminescent when aggregated in poor solvents orin the solid state, showing a novel phenomenon of aggregation-induced emission (AIE). 8-Phenylbenzo[e]acephenanthrylene (3), a ring-closed form of 1 with one of its phenyl blades locked, was emissive in thesolutions, suggesting that the AIE effects of 1 and 2 are caused by the restrictions of intramolecular rotationsof their aromatic blades in the aggregation state. The crystals of 1 and 2 emitted stronger, bluer lights thantheir amorphous powders, possibly due to the structural rigidification and conformational twisting of the dyemolecules in the crystalline phase. The light-emitting diodes with a device configuration of ITO/NPB/dye/BCP/Alq3/LiF/Al were fabricated, which emitted bluish-green and yellow lights with maximum luminanceand current efficiency up to 5000 Cd/m2 and 1.90 Cd/A, respectively.
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