Increasing the Stability of Electroluminescent Phenylenevinylene Polymers by Encapsulation in Nanoporous Inorganic Materials

Abstract

Conjugated polyphenylenevinylene oligomer (PPV) encapsulated inside basic zeolites X and Y has been prepared starting from the p-phenylenedimethylene-1,1′-bis(tetrahydrothiophen-1-ium) monomer introduced through ion exchange followed by heating the intermediate poly[1-(S-tetrahydrothiophenium)-p-phenylenethylene] oligomer at 220 °C under vacuum for 24 h. PPV loading ranged between 1.8 and 5 wt %, the sulfur content of the solid being lower than 0.03 wt %, corresponding to 1 S atom every 400 carbons. The organic oligomer has been characterized by diffuse reflectance UV-vis, IR, and MAS 13 C NMR, all the data being in agreement with that reported in the literature for pure PPV and different from those of the tetrahydrothiophenium containing intermediate polymer encapsulated inside zeolites. The solids exhibit the green emission characteristic of PPV. Although the length of the oligomer could not be determined by solid-liquid extraction or by treatment of the zeolite with HF, samples with lower precursor loading showed a 20-nm red-shifted emission with respect to that reported for well-prepared PPV. Thus, it is assumed that the length of the encapsulated oligomer has to be enough to make its properties indistinguishable from those of the nonencapsulated PPV polymer. The zeolite-encapsulated PPV was fairly stable to laser flash photolysis (laser power ∼ 10 mJ pulse -1 ). The transient spectrum has been mainly attributed to PPV polarons. A cell of a thin film of encapsulated PPV prepared by deep coating shows a current intensity vs voltage response characteristic of a diode and a weak electroluminescence operating at a dc voltage of 2.5 V.

Synthesis, structure and properties of crystalline and nanocrystalline MnPS 3 -poly(phenylene vinylene) intercalates

“…The geometrical restrictions imposed by the inorganic host could result in better-organized polymer chains that would facilitate charge injection and transfer between the conducting units. Several research groups have reported the formation of composites of PPV and inorganic two-dimensional insulators [4][5][6][7]; however, intercalates of PPV between the layers of transparent semiconducting divalent metal thiohypophosphates (M II PS 3 or M II 2 P 2 S 6 ) and their luminescent properties have not been explored. In this paper, we report the synthesis and characterization of luminescent organic-inorganic composites containing PPV-intercalated MnPS 3 .…”

Supramolecular photochemistry in zeolites: From catalysts to sunscreens

“…Typically, the gradual oxidation of C=C bonds in the polymer results in its degradation, reducing its utility in polymer light-emitting diodes. This oxidation process was markedly retarded within the zeolite [139].…”

Isolierte molekulare Drähte

“…[86,94] Konjugierte Polymere in Zeolithen sind oft überaus beständig: [22] So kann Polyacetylen in Faujasit unbegrenzt an der Luft gelagert werden, [23] und PPV bleibt im gleichen Zeolith bei der Laserphotolyse unter einer Sauerstoffatmosphäre unverändert. [24] Die TGA-Daten einiger dendronisierter konjugierter Polymere sprechen dafür, dass eine Dendronisierung die thermische Beständigkeit erhöht. So zersetzt sich PPV4(G-1) (Abschnitt 4.4, Schema 14) bei 362 8C, also 34 K oberhalb des vergleichbaren Polymers PPV(G-0), [162] und das Polyfluoren PF5 (Abschnitt 4.3) ist thermisch außerordentlich stabil (Zersetzung bei 570 8C).…”

“…lvaro et al beobachteten dennoch eine schwache Elektrolumineszenz für eine LED mit einem 50 mm dünnen Film aus zeolithumschlossenem PPV in Polyacrylamid zwischen einer Indiumzinnoxid-und einer Aluminiumelektrode. [24] Eine effiziente Elektrolumineszenz wurde für Polymer-Ton-und Polymer-MetallchalkogenidNanokomposite ermittelt. [191,192] Diese Nanokomposite ähneln zeolithumhüllten Polymeren, bis auf die Tatsache, dass die Polymerketten in zweidimensionale Zwischenräume eingeschlossen sind und nicht in eindimensionale Kanäle.…”