Synthesis of PPV and Derivatives

Copolymerization of various substituted PPV monomer units has been used to tune the electronic properties. In particular, the introduction of nonconjugated units into the polymer chain has been found to produce enhanced photoluminescence efficiencies by preventing diffusion of excitons along the chains to defect sites.33,34 

Substitution at the vinylic carbons can also be used to alter the electronic properties. For example, the substitution of electronegative -CN groups has been found to increase the electron affinity and ionization potential of PPV derivatives, thus improving the electron-injection characteristics.35,36 The synthesis is performed by the Knovenagel condensation polymerization of a terephthaldehyde and a benzene-1,4-diacetonitrile derivative, as shown in Fig. 5.10. 

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