Degradation of polymer-based light-emitting diodes during operation

Segmented block copolymers consisting of conjugated-nonconjugated sequences are useful chromophores in polymer LEDs and can lead to efficient devices of high luminance. The lifetime of such diodes depends on numerous chemical and physical interactions. Some of these pertaining to the chromophore/electrode interface can be usefully studied by optical and various electron microscopies. In typical diodes studied here, failure is associated inter alia with irregularities in the spin-coated polymer films. Atomic force microscopy provides a more detailed examination of the morphology of the polymer films.