Light emitting materials and devices of PPV type compounds containing quinolines

Five derivatives of 1,4-bis(2'-quinolinylethenyl)benzene were prepared through Wittig reaction of a di-ylide of p-xylene and two molar equivalents of quinolinyl carbaldehyde. Dyes 1a,b and 2a-c thus obtained exhibit fluorescence in quantum yields of 0.44-0.78. They are fabricated to light-emitting diodes in the form of ITO/NPB/CBP/TPBI:dye(5% wt)/Mg:Ag. The devices can be turned on at 6 V, and they displayed blue and green light at intensities up to 5000 cd/m(2) at 15 V. The compounds containing methoxy substituents, i.e. 1b and 2b,c, performed more effectively than those without, i.e..1a and 2a. The former derivatives also showed a red-shift in their emission spectra with respect to the latter.