Proton-irradiation effect on the luminescence of the MEH-PPV conjugated polymer

We report proton-irradiation effect on luminescence in the MEH-PPV conjugated polymer. While the luminescence was severely weakened by the low-energy irradiation with a high dosage, it was affected only weakly by the high-energy irradiation with a low dosage. The electroluminescence was affected by the irradiation more severely than the photoluminescence was, preserving the external quantum efficiency. While the luminescence spectrum of the severely damaged polymer was broadened with a blue-shift, a weak damage resulted only in a decrease in the luminescence intensity apparently preserving the spectral shape. The change in the luminescence spectra may be explained by chain conformational disorders as well as chain scission induced by the irradiation.