Masato Kuwabara

Organic electroluminescent devices having poly(dialkoxy-p-phenylene vinylenes) as a light emitting material

Abstract We have successfully prepared organic electroluminescent, EL, devices having poly(2,5-dialkoxy-p-phenylene vinylene)s, RO-PPV, as light emitting materials, ITO as a transparent electrode and Mg-Ag alloy as a negative electrode. Intensities of photo-, PL, and electro-luminescence for RO-PPVs depended on the chain length of alkoxy side groups. The PL intensity of the RO-PPV increased with increasing the alkoxy chain length, while the EL intensity of the devices using RO-PPV increased until a decyloxy group and then decreased. The EL intensity of the device increased with decreasing the work function of negative electrodes. This result is in good agreement with that reported by Heeger[5]. The luminance reached about 1000cd/m 2 by using both heptyloxy-PPV and MgAg alloy. It is noteworthy that usage of poly(thienylene vinylene), PTV, thin film as a buffer layer between ITO and RO-PPV results in increasing the breakdown voltage and that the luminance of the EL device reaches 1480 cd/m 2 .