Poly 2-methoxy-5- 1.4-phenylene vinylene

FIGURE 5.4 Chemical structures of photo- and electroluminescent polymers employed for polarized LEDs poly(2-methoxy-5-(2 -ethyl-hexyloxy)-p-phenylene vinylene) (MEH-PPV) poly[2,5-dioctyloxy-l, 4-diethynyl-phenylene-a/t-2,5,-bis(2 -ethylhexyloxy)-l,4-phenylene] (EHO-OPPE) poly(p-phenylene), PPP poly(3-(4-octylphenyl)-2,2 -bithiophene), PTOPT poly(p-phenylene vinylene), PPV poly(3-alkylthio-phene vinylene), P3AT Acetoxy-PPY PPV-polyester, poly(9,9-dialkyl fluorene), PF. 

H NMR study of I2 doped poly[2-buthoxy-5-methoxy phenylene vinylene] (PBMPV) has been carried out by Lee et al.114 They found magnetization recovery to follow a stretched-exponential form M(f) =Mo[l — exp(f/Ti) ] with n = 0.8 0.03, which is characteristic of a system with distribution of the correlation time. 1/Tj versus/ 172 in samples with different conductivity follows/ 172 dependence over 20 40 MPIz range indicating the main SLR is ID spin diffusion. A correlation between 1/T1 and dc conductivity has been made which is found follow a simple power law. 

FIGURE 1.2. Molecular structure of widely used it-conjugated and other polymers (a) poly(para-phenylene vinylene) (PPV) (b) a (solid line along backbone) and it ( clouds above and below the a line) electron probability densities in PPV (c) poly(2-methoxy-5-(2 -ethyl)-hexoxy-l,4-phenylene vinylene) (MEH-PPV) (d) polyaniline (PANI) (d.l) leucoemeraldine base (LEB), (d.2) emeraldine base (EB), (d.3) pernigraniline base (PNB) (e) poly(3,4-ethylene dioxy-2,4-thiophene)-polystyrene sulfonate (PEDOT-PSS) (f) poly(IV-vinyl carbazole) (PVK) (g) poly(methyl methacrylate) (PMMA) (h) methyl-bridged ladder-type poly(jf-phenylene) (m-LPPP) (i) poly(3-alkyl thiophenes) (P3ATs) (j) polyfluorenes (PFOs) (k) diphenyl-substituted frares -polyacetylenes (f-(CH)x) or poly (diphenyl acetylene) (PDPA). 

The XPR has been used to synthesize poIy(2,5 dimethoxy p-phenylene vinylene)(DM-PPV) and the reaction is the same as shown in Figure 2 except that methoxy substituents are present at the 2 and 5 positions of the phenylene ring. The chlorine precursor route (CPR) is used to prepare poly(phenoxy phenylene vinylene) (PO-PPV) and the reaction is shown in Figures. ... 

Other CPs worth mentioning as having been studied for secondary battery applications include poly(3-butyl-thiophene-co-3-methyl-thiophene) and poly(di-methoxy-phenylene vinylene) [730]. Pandey and Prakash [731] investigated a Zn/poly(indole) secondary battery and found a maximum capacity of 90 Ah/kg with an open circuit potential of 1.45 V and good coulombic efficiency. 

TT-Conjugated linear polymers have attracted attention as materials in organic EL devices. The device using poly(p-phenylene vinylene) (PPV) sandwiched between indium oxide and aluminum electrodes emits green-yellow light at 14 V [167]. The quantum efficiency for the device was up to 0.05% photon per electron. EL devices based on poly[2-methoxy-5-(2 -ethyl)-... 

The sulfonium precursor route may also be applied to alkoxy-substituted PPVs, but a dehydrohalogenation-condensation polymerization route, pioneered by Gilch, is favored 37]. The polymerization again proceeds via a quinomethide intermediate, but die syndicsis of the conjugated polymer requires only two steps and proceeds often in improved yields. The synthesis of the much-studied poly 2-methoxy-5-(2-ethylhexyloxy)-l,4-phenylene vinylene], MEH-PPV 15 is outlined in Scheme 1-5 33, 35]. The solubility of MEH-PPV is believed to be enhanced by the branched nature of its side-chain. 

Poly(2-methoxy, 5-(2 -ethylhexyloxy)-1,4-phenylene vinylene) MEH-PPV Emission peak = 605 nm p-type doping by sulfuric acid (H2SO4) -type doping by sodium (electron donor) Iodine (I2) = electron acceptor = > oxidizing agent... 

L Smilowitz, A Hays, AJ Heeger, G Wang, and JE Bowers, Time-resolved photoluminescence from poly[2-methoxy, 5-(2-ethyl-hexyloxy)-p-phenylene-vinylene] solutions, gels, films, and blends, J. Chem. Phys., 98 6504-6509, 1993. 

Preparation of Poly[2-(3,7-dimethyloctyloxy)- 5-methoxy-p-phenylene vinylene] (14) (Chart 2.147). 

L. Lutsen, P. Adriaensens, H. Becker, A.J. Van Breemen, D. Vanderzande, and J. Gelan, New synthesis of a soluble high molecular weight poly(arylene vinylene) poly[2-methoxy-5-(3,7-dimethyloctyloxy)-p-phenylene vinylene]. Polymerization and device properties, Macromolecules, 32 6517-6525, 1999. 

F. Wudl and G. Srdanov, Conducting Polymer Formed of Poly(2-Methoxy-5- (2 -Ethylhexyloxy)-p-Phenylene Vinylene), U.S. Patent 5,189,136, February 23, 1993. 

P.L. Burn, A.W. Grice, A. Tajbakhsh, D.D.C. Bradley, and A.C. Thomas, Insoluble poly [2-(2 -ethylhexyloxy)-5-methoxy-l,4-phenylene vinylene] for use in multiplayer light-emitting diodes, Adv. Mater., 9 1171-1176, 1997. 

B. Sohn, K. Kim, D.S. Choi, Y.K. Kim, S.C. Jeoung, and J. Jin, Synthesis and luminescence properties of poly[2-(9,9-dihexylfluorene-2-yl)-l,4-phenylene vinylene] and its copolymers containing 2-(2-ethylhexyloxy)- 5-methoxy-l,4-phenylene vinylene units, Macromolecules, 35 2876-2881, 2002. 

Y.H. Niu, Q. Hou, and Y. Cao, High efficiency polymer light-emitting diodes with stable saturated red emission based on blends of dioctylfluorene-benzothiadiazole-dithienylbenzothiadiazole terpolymers and poly[2-methoxy,5-(2-ethylhexoxy)-l,4-phenylene vinylene], Appl. Phys. Lett., 82 2163-2165, 2003. 

MEH-PPV Poly[2-(2 ethylhexyloxy)-5-methoxy-1,4-phenylene vinylene Red-orange 610... 

Poly[2-methoxy-5-(3, 7 -dimethyloctyloxy)]-l,4-phenylene vinylene Polycyclic aromatic hydrocarbon Poly(3,4-ethylenedioxythiophene)... 

In order to learn about the true quantum efficiency of photogeneration one therefore has to study the photoinduced charge generation mechanism at faster time scales. Pump probe spectroscopy utilising a few optical-cycle laser pulses (5-6 fs) in the visible spectral range with broadband frequency conversion techniques [89] now makes it possible to study extremely fast optically-initiated events with unprecedented time resolution. Such a setup was used to time-resolve the kinetics of the charge transfer process from a polymer chain to a fullerene moiety in thin films of poly[2-methoxy, 5-(3, 7 -dimethyl-octyloxy)]-p-phenylene vinylene (MDMO-PPV) and [6,6]-phenyl C6i butyric acid methyl ester (PCBM). Solutions prepared from 1 wt% solutions of toluene on thin quartz substrates were studied. 

Fig. 3.29(b) shows the published J-V curves of an Al/OCiCio/ITO diode by Jain et al. [40], [OCiCio is poly(2-methoxy-5-(3,7-dimethyloctyloxy)-p-phenylene vinylene).] In this paper [40] Jain et al. attributed the extremely fast rise of the hole current at low voltages to Shockley like current due to the forward biased Al Schottky contact. In their later paper [56] Jain et al. showed that by including the PFE they can fit the theory of bulk limited trap controlled space charge currents with the same experimental results (see Fig. 3.29(b)). Jain et al. [40] suggested that PFE induces the high injection effect earlier, which presumably makes the Schottky barrier at the Al contact small. 

Mihailetchi [134] investigated the open circuit voltage of the bulk heterojunction organic solar cells based on methanol-fullerene [6,6]-phenyl C61-butyric acid methyl ester (PCBM) as electron acceptor and poly[2-methoxy-5(3 ,7 -dimethyloctyloxy)-p-phenylene vinylene] (OC1C10-PPV) as an electron donor. It is known that a single layer device follows the MIM model [166] and the open circuit voltage V0c is equal to the difference in the work functions of the metal electrodes [134], If charges accumulate in the... 

P. Kumar, A. Misra, M.N. Kamalasanan, S.C. Jain, R. Srivastava, V. Kumar, Charge transport through conducting organic poly(2-methoxy-5-(2-ethylhexyloxy)-l,4-phenylene vinylene),./. Phys. D Appl. Phys. 40 (2007) 561. 

Figure 108 Current-voltage data (points) from single layers of poly[2-methoxy,5-(2-ethylhexoxy)-l,4-phenylene vinylene] (MEH-PPV) provided with Au anodes and different cathodes (Ca, Al, and Au as indicated in the figure). The data normalized to the sample thickness, d, and the electric field accounted for the built-in potential (f/bi) AU=U — f/bi, where U is the applied voltage. Solid lines plotted according to predictions of Eq. (270). After Ref. 474 (see also Ref. 475). Copyright 1998 American Physical Society.

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