FRET-Assisted Deep-Blue Electroluminescence in Intercalated Polymer Hybrids

Polymer/layered silicate nanocomposites (PSNs), obtained through a bottom-up strategy with both free and intercalated poly(styrene) carrying fluorescent terfluorene side-chains, allow for the fabrication of optically transparent films with controlled morphology and fine-tuning of the organic/inorganic interface properties. The successful assessment of the hybrid material as an efficient emitter in a light-emitting device is reported, and the complex mechanism responsible for its emission is elucidated. The approach allows planarization and chemical and photostabilization of short intercalated oligo(fluorene)s whose emissive properties are enhanced thanks to exciton localization. Both photoluminescence and electroluminescence are assisted by a sensitization mechanism exploiting resonant energy transfer from nonplanar, nonintercalated polymer pendant conformers wrapping the silicates. A single-layer, solution-processable, hybrid light emitting diode (LED) displays deep-blue electroluminescence with a record external quantum efficiency, for this class of materials, of 1.2%, maximum luminance of 860 cd/m 2, Commission Internationale de l’Eclairage (CIE) 1931 ( x, y ) chromaticity coordinates of (0.158, 0.114), and low efficiency roll-off thanks to the separation of the emissive region from the charge transport one.