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Wu, Y.-C., Ren, X.-K., Chen, E.-Q., Lee, H.-M., Duvail, J.-L., Wang, C.-L. & Hsu, C.-S. (2012) Preservation of Photoluminescence Efficiency in the Ordered phases of Poly(2,3-diphenyl-1,4-phenylenevinylene) via Disturbing the Intermolecular pi-pi Interactions with Dendritic Aliphatic Side Chains. Macromolecules, 45 4540–4549.
Added by: Laurent Cournède (2016-03-10 21:28:39) |
| Type de référence: Article DOI: 10.1021/ma300640n Numéro d'identification (ISBN etc.): 0024-9297 Clé BibTeX: Wu2012 Voir tous les détails bibliographiques  |
Catégories: PMN Mots-clés: conjugated polymers, copolymers, derivatives, electroluminescent polymers, energy-transfer, light-emitting-diodes, molecular aggregation, poly(p-phenylene vinylene)s, polyfluorenes, precursor route Créateurs: Chen, Duvail, Hsu, Lee, Ren, Wang, Wu Collection: Macromolecules |
Consultations : 1/520
Indice de consultation : 3% Indice de popularité : 0.75% |
| Résumé |
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To understand the relation between the solid-state phase structures and the photophysical properties of poly(2,3-diphenyl-1,4-phenylenevinylene) (DP-PPV) derivatives, three DP-PPV derivatives, P1-P3, were designed, synthesized via Gilch polymerization and characterized. Among the polymers, PI is a reported highly emissive poly(2,3-diphenyl-5-hexyl-p-phenylenevinylene), and P2 and P3 are novel DP-PPV derivatives, which are purposely designed to bear hydrophobic and hydrophilic Percec-type dendrons as side chains. The bulkiness and hydrophobic hydrophilic natures of the side chains show strong effects on photophysical properties of the polymers. The solutions and as-casted films of P1-F3 all show remarkably high photoluminescence (PL) efficiency (Phi(PL)) ({>}80\% in chloroform solution, and {>}63\% for the as-casted films). However, Phi(PL) of P1 and P3 decrease significantly to 30\% after cooled their polymer melts to room temperature. Through the phase behavior analysis by differential scanning calorimetry (DSC), and phase structure analysis by wide-angle X-ray diffraction (WAXD), the decrease of Phi(PL) can be elucidated and attributed to the ordering of the solid-state structures of PI and P3. To our surprise, Phi(PL) of P2 is preserved even in an ordered solid-state phase, and it is insensitive to the structural ordering. Structural analysis of P2 revealed that the aliphatic dendritic side chains of P2 effectively disturbing the intermolecular pi-pi interactions among the conjugated backbones, which allows the preservation of Phi(PL) in the environment with ordered packing of DP-PPV molecules. The results of time-resolved PL decay experiments also confirmed that P2 possesses long-lived decay time because of excitons confined more effectively for emissive relaxation.
Added by: Laurent Cournède |