Poly 2-methoxy

The absorption spectrum of poly(2-methoxy-5-(2 -ethyI-hexyIoxy)-/mra-phenyIene vinylene) (MEH-PPV) is shown in Figure 7-8a. Phcnylene-based conducting polymers such as MEH-PPV exhibit multiple absorption features extending well into... 

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... 

F Wudl and G Srdanov, Conducting Polymer Formed of Poly(2-Methoxy,5-(2 -Ethyl-Hexyloxy)-p-Phenylenevinylene), U.S. Patent 5,189,136, 1993. 

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. 

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. 

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. 

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. 

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. ... 

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

EDOT) coated CdSe nanorods as a function of the quantity of poly [2-methoxy-5-(3, 7 -dimethy locty loxy)-1,4-phenylenevinylene] (MDMO-PPV) added (solvent CHC13).151 (Reprinted with permission from D. Aldakov et al., Eur. Phys. J. Appl. Phys. 2006, 36, 261-265. Copyright the European Physical Journal.)... 

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.

These problems were eliminated by the use of modified PPV derivatives ", such as poly[2-methoxy-5-(2-ethylhexyloxy)-4-phenylene vinylene] (MEH-PPV) compound 2, see Table 6.1, which are soluble in organic solvents. The presence of lateral substituents in the polymers 3-6 shown in Table 6.1 induces a lower... 

---