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PPV Derivatives (ppv + derivative)

Distribution by Scientific Domains

Polymers and Materials Science	75%

Selected Abstracts

Field-effect transistors based on PPV derivatives as a semiconducting layer

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2009
Woo-Hyung Lee
Abstract A series of modified thiophene groups containing PPV-based semiconducting materials, poly[(2,5-bis(octyloxy)-1,4-phenylenevinylene)-alt-(2,2,bithienylenevinylene)] (PPBT), poly[(2,5-bis(octyloxy)-1,4-phenylenevinylene)-alt-(5,5-thiostilylenevinylene)] (PPTVT), have been synthesized through a Horner coupling reaction. From the FTIR and 1H NMR spectroscopy, the configuration of the vinylene groups in the polymers was all trans (E) geometry. The weight-average molecular weights (Mw) of PPBT and PPTVT were found to be 11,700 and 11,800, with polydispersity indices of 2.51 and 2.53, respectively. PPBT and PPTVT thin films exhibit UV,visible absorption maxima at 538 and 558 nm, respectively, and the strong absorption shoulder peaks at 578 and 602 nm, respectively. Solution processed field-effect transistors (FET) fabricated using all the polymers showed p -type OTFT characteristics. The field-effect mobility of the PPTVT was obtained up to 2.3 × 10,3 cm2 V,1 s,1, an on/off ratio of 1.0 × 105 with ambient air stability. Studies of the atomic force microscopy (AFM) and X-ray diffraction (XRD) analysis of the polymer thin films revealed that all the polymers were amorphous structure. The greater planarity and rigidity of PPTVT compared to PPBT results in elongation of conjugation length and better ,,, stacking of polymer chains in amorphous region, which leads to improved FET performance. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 111,120, 2009 [source]

Luminescence properties of poly- (phenylene vinylene) derivatives

POLYMER INTERNATIONAL, Issue 3 2008
Cuong Ton-That
Abstract BACKGROUND: Conjugated polymers, especially those of the poly(phenylene vinylene) (PPV) family, are promising candidates as emission material in light-emitting devices. The aim of this work was to investigate the dependence of the luminescence properties of PPV-based derivatives on their polymer structure, especially side groups. RESULTS: Three PPV derivatives, BEHPPV, MEHPPV and MEHSPPV, were synthesised and characterised by photoluminescence (PL) and cathodoluminescence (CL) spectroscopies in the temperature range 10,300 K. PL and CL spectra of the polymers exhibit similar luminescence peaks, which undergo a blue shift with increasing temperature. The shift in wavelength is accompanied by variations in the relative intensities of emission peaks. Both BEHPPV and MEHPPV display emission characteristics of the PPV backbone, but the peak of MEHPPV shifts to a longer wavelength in comparison with the corresponding peak of BEHPPV at the same temperature. The luminescence spectra of MEHSPPV, which has a sulfanyl incorporated in the side chain, are considerably different from those of the two other derivatives. CONCLUSIONS: The results demonstrate that the luminescence properties depend strongly on the chain conformations of the conjugated backbone, which are affected by polymer side chains. Copyright © 2007 Society of Chemical Industry [source]

Synthesis, characterization, and electroluminescence of new conjugated PPV derivatives bearing triphenylamine side-chain through a vinylene bridge

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 12 2007
Zhan'ao Tan
Abstract Three new conjugated poly(p -phenylene vinylene) (PPV) derivatives bearing triphenylamine side-chain through a vinylene bridge, poly(2-(4,-(diphenylamino)phenylenevinyl)-1,4-phenylene-vinylene) (DP-PPV), poly(2-(3,-(3,,7,-dimethyloctyloxy)phenyl)-1,4-phenylenevinylene- alt -2-(4,- (diphenylamino)phenylenevinyl)-1,4-phenylenevinylene) (DODP-PPV), and poly(2-(4,-(diphenylamino)phenylenevinyl)-1,4-phenylenevinylene-co-2-(3,,5,-bis(3,,7,-dimethyloctyloxy)-1,4-phenylenevinylene) (DP-co-BD-PPV), were synthesized according to the Gilch or Wittig method. Among the three polymers, the copolymer DP-co-BD-PPV is soluble in common solvents with good thermal stability with 5% weight loss at temperatures higher than 386°C. The weight-average molecular weight (Mw) and polydispersity index (PDI) of DP-co-BD-PPV were 1.83,×,105 and 2.33, respectively. The single-layer polymer light-emitting diodes (PLEDs) with the configuration of Indium tin oxide (ITO)/poly (3,4-ethylenedioxythiophene): poly(4-styrene sulfonate)(PEDOT:PSS)/DP-co-BD-PPV/Ca/Al were fabricated. The PLED emitted yellow-green light with the turn-on voltage of ca. 4.9,V, the maximum luminance of ca. 990,cd/m2 at 15.8,V, and the maximum electroluminescence (EL) efficiency of 0.22,cd/A. Copyright © 2007 John Wiley & Sons, Ltd. [source]

Computer Simulation of Long Side-Chain Substituted Poly(phenylene vinylene) Polymers

CHEMPHYSCHEM, Issue 3 2004
Hsiao-Ching Yang
Abstract A molecular dynamics (MD) simulation was employed to investigate structure features and segment orientation of four poly(phenylene vinylene) (PPV) derivatives with long, flexible side chains at room temperature. In the simulations, the main chains of the polymers were found to be semirigid and exhibit a tendency to coil into ellipsoidal helices or form zigzag conformations of limited regularity. The simulations show that continuous quasi-coplanar segments along the backbone are in a range of ,2,4 repeat units. The ordered orientation and coupling distance of interchain aromatic rings can be correlated with optical properties of materials. A simplified quantum-mechanical method was developed to investigate optical properties based on MD trajectories. The method was tested to simulate the absorption spectra of four PPV derivatives. The absorption maxima of the calculated spectra are in reasonable agreement with experimental data. This work implies that long-range electron transfer along the backbones of these polymers may not occur, but may be mediated by interchain interactions. [source]