Rubbing-Induced Molecular Orientation and Polarized Electroluminescence in Conjugated Polymer

Abstract

A preferred molecular orientation in a conjugated polymer, poly(2,5-dinonyloxy-1,4-phenylenevinylene) (NO-PPV), can be obtained by a unidirectional rubbing treatment of its thin solid film. Polarized electroluminescence with dichroic ratio of 1.6 as well as anisotropic optical absorption and photoluminescence have been observed for the rubbed NO-PPV film. An analysis of orientation distribution in the rubbed NO-PPV film suggested that radiative decay occurs in both oriented and unoriented layers. Surface geometry measurements suggested that plastic deformation of the polymer along the rubbing direction was the cause of the preferred orientation even in the conjugated polymer with rigid main chain structure.