Poly luminescent conjugated polymers

Examples of the optical pumping of solutions of luminescent conjugated polymers include laser action at 596 nm of poly[2-methoxy-5-(2-ethylhexyloxy)-p-phenylenevinylene] (MEH-PPV) using excitation with 6 ns Nd YAG third harmonic pulses (354.7 nm). ° Tuning of hexane solutions of the co-polymer poly(2,2, 5,5 -tetraoctyl-p-terphenyl-4,4 -xylene-vinylene-p-phenylenevinylene) (TOP-PPV) was possible between 414 and 456 mn, similar to the classical coumarin laser dyes. ... 

Although the exact mechanism of the fluorenone formation is not known, it is believed that the monoalkylated fluorene moieties, present as impurities in poly(dialkylfluorenes), are the sites most sensitive to oxidation. The deprotonation of rather acidic C(9)—H protons by residue on Ni(0) catalyst, routinely used in polymerization or by metal (e.g., calcium) cathode in LED devices form a very reactive anion, which can easily react with oxygen to form peroxides (Scheme 2.26) [293], The latter are unstable species and can decompose to give the fluorenone moiety. It should also be noted that the interaction of low work-function metals with films of conjugated polymers in PLED is a more complex phenomenon and the mechanisms of the quenching of PF luminescence by a calcium cathode was studied by Stoessel et al. [300],... 

In another approach, a fluorescent conjugated polymer was used as the material for the preparation of a chemosensor to detect 2,4,6-trinitrotoluene (TNT) and its related nitroaromatic compounds. To this end, microparticles, made of three-dimensionally cross-linked poly(l,4-phenylene vinylene) (PPV) via emulsion polymerization, were synthesized [61]. This material was chosen due to its high fluorescence intensity and sensitivity to changes in its microenvironment. The chemosensor was exposed to vapour containing different amounts of TNT and quenching of the polymer luminescence at 560 nm was observed after excitation at 430 nm. The dependence of the fluorescence signal in response to the analyte was described by a modified Stem-Volmer equation that assumes the existence of two different cavity types. The authors proposed the modified Stem-Volmer equation as follows ... 

Long-lived photoluminescence, at 826 nm, is reported (t 15 (is) for thin films of the processable, -conjugated polymer, poly(3-hexylthio-phene) (93JA8447). Excitation of the n—n transition with 518 nm light (So >S ) yields only very weak luminescence of 826-nm light, even at 18 K. The emission is enhanced, to point where it can be observed at room temperature, when the excitation wavelength is 250 nm, but it is completely quenched by oxygen. Prompt fluorescence decays within... 

Phenylene-based polymers are one of the most important classes of conjugated polymers, and have been the subject of extensive research, in particular as the active materials in light-emitting diodes (LEDs) [1,2] and polymer lasers [3]. These materials have been of particular interest as potential blue emitters in such devices [4], The discovery of stable blue-light emitting materials is a major goal of research into luminescent polymers [5]. Poly(para-phenylene) (PPP, Scheme 1, 1) is a blue emitter [6], but it is insoluble and so films of PPP have to be prepared via precursor routes [7]. Substitution with long alkyl... 

Rothe C, Guentner R, Scherf U, Monkman AP (2001) Trap influenced properties of the delayed luminescence in thin solid films of the conjugated polymer poly(9,9-di(ethylhexyl)fluorene). J Chem Phys 115(20) 9557—9562... 

K-Conjugated polymers and oligomers are organic materials with many interesting and useful properties [1, 2], Examples of this class of materials include polyacetylene, polythiophene, polypyrrole, poly(phenylenevinylene) and their derivatives. Electronic conductivity, luminescence and nonlinear optical behavior are all observed in these materials and these properties have been exploited in applications such as electroluminescent devices (polymer light-emitting devices or PLEDs), electrostatic coatings, electrochromic windows, chemical sensors and memory devices [3-9]. 

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