Temperature dependence of photoluminescence in MEH-PPV blend films

The temperature dependence of the optical properties in poly [2-methoxy-5-(2′-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) blending with 2-(4-biphenyl)-5-(4-tertbutylphenyl)-1,3,4-oxadiazole (PBD) has been investigated. The blending influence on the chain conformation and exciton energy migration in blend film is described. The PL emission from the pure and blend films are all blue shifted with increasing temperature. An addition of PBD in MEH-PPV films suppresses the relative intensity of 0-1 vibronic peaks at lower temperature. This phenomenon will not be promoted with increasing temperature, attributed to a temperature-dependent migration process of singlet excitons.