Photoluminescent and electroluminescent properties of DCM-1 dispersed poly(p-phenylene vinylene) derivatives

The single layer devices utilizing poly[2-(carbazol-9-yl)-5-(2-ethylhcxyloxy)-1,4-phenylene vinylene] (CzEh-PPV) and poly[2-{4-[5-(4-tert-butylphenyl)-l,3,4-oxadiazolyl]-phenyl}-5-(2-ethythexyloxy)-l,4-phenylene vinylene] (OxdEh-PPV) doped with varying weight percent of 4-(dicyanomethylene)-2-methyl-6-[p-(dimethylamino)styryl]-4H-pyran (DCM-1) were fabricated and their photo luminescence (PL) and electroluminescence (EL) properties were discussed in this investigation. The PL spectra of DCM-1 doped polymers show that the emission is mostly from DCM-1 and Förster energy transfer may occur between DCM-1 and the two polymers. On the other hand, field-dependence of the emission spectra of EL devices was observed in detail. For the CzEh-PPV/DCM-1, the emission at the wavelength of 534 nm remains unchanged as the level of DCM-1 increases, whereas the peak at 572 nm is intensified with increasing both the additive level and applied electric field. For the OxdEh-PPV/DCM-1, the main peak is red-shift as the level of DCM-1 increases and blue-shift as the applied electric field does.