Nanoscale Optical Microscopy of Conjugated Polymer Films

Near-field scanning optical microscopy (NSOM) has been used to probe the photoluminescence, linear dichroism and photoconductivity of free-standing poly(p-phenylene vinylene) (PPV) films with spatial resolution better than 100 nm. We observe a strong correlation between each of these properties and film morphology in both non-oriented and stretch-oriented films. The non-oriented PPV thin films exhibit mesoscale non-uniform photoluminescence correlated to polymer clusters. Upon stretch-orientation, PPV thin films show average polymer chain orientation parallel to the stretch axis as well as distinct areas of perpendicular molecular orientation correlated to film topography.