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Department of Physics

Staff profile

Publication details for Professor Andy Monkman

Lyons, BP & Monkman, AP (2004). A comparison of the optical constants of aligned and unaligned thin polyfluorene films. Journal Of Applied Physics 96(9): 4735-4741.
  • Publication type: Journal papers: academic
  • ISSN/ISBN: 0021-8979
  • Keywords: LIGHT-EMITTING-DIODES; ELECTROLUMINESCENT POLYMER-FILMS; ENERGY-TRANSFER; BLUE; ORIENTATION; POLY(9,9-DIOCTYLFLUORENE); PHOTOPHYSICS; ANISOTROPY; BLENDS; LAYERS

Author(s) from Durham

Abstract

The optical constants of aligned and unaligned thin polyfluorene films
have been investigated using variable angle spectroscopic ellipsometry
over the spectral range 250-1000 nm. Films were prepared by spin
coating, with alignment achieved by deposition on a rubbed polyimide
substrate followed by annealing. The films could be well modeled by
layers with uniaxial anisotropy. The unaligned film had its optical
axis oriented normal to the film surface and was optically negative.
There was large absorption and dispersion of the refractive index
perpendicular to the optical axis and small absorption and dispersion
of the refractive index parallel to it. The aligned film had its
optical axis oriented in plane, normal to the rubbing direction, and
was optically positive. There was large absorption and dispersion of
the refractive index parallel to the optical axis and small absorption
and dispersion of the refractive index perpendicular to it. These
results will be useful in the design of polarized light-emitting
devices using polyfluorene as an active layer. (C) 2004 American
Institute of Physics.