LUMINESCENCE EXCITATION SPECTROSCOPY OF HIGHLY ORIENTED POLY(3-OCTYLTHIOPHENE)-POLYETHYLENE BLENDS

Polarized luminescence spectra of gel-processed blends of poly(3-octyl thiophene) and ultra-high molecular weight polyethylene are reported f or different excitation energies and for several concentrations of the conjugated polymer. The films are oriented by tensile drawing to a dr aw ratio of 62. The strong anisotropy of the emission spectra indicate s that polyoctylthiophene is very well oriented along the stretching a xis. At high concentration stretching induces the orientation of polyt hiophene aggregates. At low concentration the order and orientation of polyethylene are transferred to the conjugated guest. A mobility edge in the absorption tail is observed. The localized lower energy states show the strongest anisotropy and correspond to the longer conjugatio n length segments.