Navegando por Palavras-chave "Cyano group"

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    Evaluation of the photocurrent value for poly(2,5-dicyano-p-phenylene-vinylene)-co-(p-phenylene-vinylene) (DCN-PPV/PPV)
    (Springer, 2016) dos Santos, Fabio Santana; Bertuzzi, Diego L.; Pedroso, Alex V.; Voinarovicz, Marco A.; Klider, Karine C. C. W. dos S.; Peres, Laura O. [UNIFESP]; Garcia, Jarem R.
    A method to obtain poly(2,5-dicyano-p-phenylene-vinylene)-co-(p-phenylene-vinylene) (DCN-PPV/PPV) block copolymer was developed. The structural characteristics of the copolymer and its capability to generate a photocurrent were evaluated. IR spectra indicate the complete conversion of precursor copolymer into DCN-PPV/PPV at 250 A degrees C under low-pressure conditions. The DCN-PPV/PPV polymer optical band gap was determined based on the observed UV-Vis spectral data by using Tauc's equation. The two linear regions in the Tauc curve (E-g = 2.63 eV and 2.02) revealed the formation of a block copolymer. Thermal analysis showed that DCN-PPV/PPV has a higher stability than PPV and starts to degrade at 317 A degrees C in air. The electronic parameters of DCN-PPV/PPV (IP = 5.25 eV, EA = 3.30 eV, and E-g = 1.95 eV) indicate that the cyano groups reduce the LUMO energy level without affecting the HOMO energy by much. DCN-PPV/PPV photoactivity measurements show higher photocurrent values compared to those for PPV.
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    Ultrathin films of poly(2,5-dicyano-p-phenylene-vinylene)-co-(p-phenylene-vinylene) DCN-PPV/PPV: A Langmuir and Langmuir-Blodgett films study
    (Elsevier B.V., 2015-02-20) Soares, Cecilia Goncalves [UNIFESP]; Caseli, Luciano [UNIFESP]; Bertuzzi, Diego Luan; Santos, Fabio Santana; Garcia, Jarem Raul; Peres, Laura Oliveira [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade Estadual de Ponta Grossa (UEPG)
    Manipulation of polymeric films at the molecular level can be appropriate to improve the properties of optoelectronic devices. in this paper, the copolymer poly(2,5-dicyano-p-phenylene-vinylene)-co-(p-phenylene- vinylene) (DCN-PPV/PPV) was spread on the air-water interface forming Langmuir films. the monolayers were investigated with surface pressure-area isotherms, and polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS). the monomolecular films were then transferred to solid supports through the Langmuir-Blodgett (LB) technique, and characterized by PM-IRRAS and atomic force microscopy, with the viability of the film as an optical device investigated with fluorescence spectroscopy. the immobilization of this copolymer on solid supports as LB films provided a molecular architecture with control of their molecular properties, which may have applications for the production of optoelectronic devices. (C) 2014 Elsevier B.V. All rights reserved.