| Abstract
| - A series of cyano-containing distyrylbenzenes were synthesized as the model compoundsto systematically study the effect of cyano substituents on the redox behaviors of conjugated molecules.By introducing the electron-withdrawing functional groups (cyano and dicyanovinyl) onto the phenylenering, both electron affinity and electrochemical stability of the resulting distyrylbenzenes are greatlyenhanced. The results enabled us to design and synthesize a new class of highly electron affinitive,fluorene-based copolymers with these cyano-containing chromophores as comonomers. The effects ofacceptor strength and side chain on electron-transporting properties of these polymers were alsoinvestigated. By properly adjusting copolymer compositions, a combined high electron affinity andtransport was achieved in a statistic copolymer, poly(fluorenebenzothiadiazole−cyanophenylenevinylene)(PFB−CNPV). An external quantum efficiency up to 0.88% and brightness as high as 4730 cd/m2 wereachieved in a double-layer light-emitting diode (LED) using PFB−CNPV as the emitting layer.
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