Silyl-substituted PPV

Generally, silyl substituents seem to retard the hole-transporting ability of PPV. As a result, devices fabricated from silyl-substituted PPVs suffer from a high turn-on voltage. To improve the EL efficiency of PLEDs fabricated from Si-PPVs, the introduction of additional hole injection layer or copolymerization with electron-rich comonomers is required. 

A modification of the Thom-Csanyi ROMP route to PPV makes use of a silyl-substituted paracyclophane derivative, which, under ROMP conditions, reacted to give a soluble precursor polymer. fransformation of the PPV could be achieved by treating the precursor polymer with acid or by hydrolysis of the silyl group followed by thermal treatment (Fig. 73). Because the pofymerization is living, polymers and block copolymers of well-defined molecular weight can be prepared [916]. 

Table 2 Optical properties of PPV and its silyl-substituted derivatives... 

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