Study of 4,4′-bis(4-dimethylaminostyryl) benzene based diodes

The electrical and optical characteristics of 4,4′-bis(4-dimethyl amino styryl) benzene (DMASB), a new derivative of poly(p-phenylene vinylene) (PPV) have been investigated for use as an active layer in light emitting diodes (LEDs). Analysis of photoluminescence and Raman spectra shows that the oligomer has properties close to those of PPV and the incorporated amino groups do not change significantly the optical absorption of PPV. The current–voltage characteristics of the DMASB based diodes show rectifying behavior, which is dependent on the nature of metals used for the electrodes. Analysis of the polymer–metal interfaces reveals that chemical interactions between the polymer and the metals have occurred and these results are related to the electrical behaviour of the diodes.