Researches On Fluorescence Materials Based On Arylfumaronitrile And Arylmaleimide With Tunable Solid-State Emission

Organic fluorophores that exhibit an intense and tunable emission in solid states,particularly those with an emission across the whole visible spectrum,have received much attention owing to their extensive application in the fabrication of organic laser,storage,fluorescent sensors and full-color displays.However,most traditional organic luminescent materials show low emission efficiency or even non-emission in the aggregated state,which is attributed to inherent strong intermolecular ?-? stacking interactions consuming the excitation energy.Although the discovery of a novel phenomenon,termed aggregation-induced emission(AIE),offers an effective approach for the development of organic materials with highly efficient solid state luminescence,solid-state luminescent materials based on a simple core backbone with tunable emission color are still extremely limited.This thesis mainly contributes to develop materials with high efficiency and tunable solid-state luminescence,including small molecules and polymers,through modifying the chemical structure or changing the topology structure of conjugated polymers.Its main contents are summarized as follows:(1)Six differently substituted arylfumaronitrile derivatives(compounds 2-7)were designed and synthesized.Compounds 2-7 have weak emission or even non emission in the solution,but very strong in the powders,crystals and nanoparticles,showing obvious aggregation induced emission(AIE)behavior and fluorescent quenching for explosives.By adjusting the electronic effect of substituent group,changing the conformation or packing way of molecules,the full-color emission of arylfumaronitriles in solid state were successfully realized.(2)Phenylfumaronitrile with high fluorescence quantum yield was selected as the backbone,reacted with 9,9-dioctylfluorene,9-(1-octylnonyl)-9H-carbazole,N-octylph-enyl maleimide and N-octylthiophene maleimide to obtain alternating copolymers.By changing the push-pull effect of the comonomer,the emission of polymers in solution was successfully adjusted,and covered whole visible range from deep blue to deep red.In films,they emit from sky blue,yellow to orange red.(3)Arylmaleimide derivatives(TPM and TIM)were employed as the core to synthesize branched polymers,including star-shape and hyperbranched polymers.The band gap of these branched polymers can be adjusted by using the different cores,changing the feed ratio of the core and the composition of the branches.As a result the luminescent color of the branched polymers can be controlled from yellow to red.Due to the three-dimensional configuration of branched polymers,the two type polymers exhibit high fluorescence quantum yield,good film-forming ability and high thermal stability.Therefore,the branched polymers with high fluorescence quantum yield and excellent luminescence performance were chosen as the light emitting layer to fabricate devices by solution method,and the high efficiency and stable white light and orange light emission were obtained.