Photoelectrochemical, photophysical and morphological studies of electrostatic layer-by-layer thin films based on poly(p-phenylenevinylene) and single-walled carbon nanotubes

Almeida, Luiz Carlos Pimentel; Zucolotto, Valtencir; Domingues, Raquel Aparecida; Atvars, T. D. Z.; Nogueira, Ana F.

doi:10.1039/c1pp05221g

Cited by 6 publications

(3 citation statements)

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“…The difference between the optical E g (2.02 eV) and electrochemical E g (1.95 ± 0.05 eV) values in DCN-PPV/PPV was not important, which shows a good correlation between different methods for the determination of E g . The stabilized photocurrent values of these films are about half the value of the stabilized photocurrent of the device prepared by Almeida, L.C.P, et al [29] into which a layer This factor indicates a great potential for use of this kind of material in photovoltaic devices. The first cycle potential scan gave an onset potential of oxidation (E' ox ) at ca.…”

Section: Resultsmentioning

confidence: 80%

Evaluation of the photocurrent value for poly(2,5-dicyano- p -phenylene-vinylene)-co-(p-phenylene-vinylene) (DCN-PPV/PPV)

Santos

Bertuzzi

Pedroso

et al. 2016

J Solid State Electrochem

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A method to obtain poly(2,5-dicyano-p-phenylenevinylene)-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°C under lowpressure 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 eVand 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°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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Section: Resultsmentioning

confidence: 80%

Evaluation of the photocurrent value for poly(2,5-dicyano- p -phenylene-vinylene)-co-(p-phenylene-vinylene) (DCN-PPV/PPV)

Santos

Bertuzzi

Pedroso

et al. 2016

J Solid State Electrochem

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show abstract

“…CNT have been combined with PEDOT, 237 PAni, 238,239 PPy, [240][241][242][243][244] and PPV 245,246 with promising applications as biosensors. 238,239,242,244 Other polyelectrolytes based on dendrimers have been reported as potentiometric sensors in presence of CNT.…”

Section: Thickness Of the Lbl-mwnt Electrodes As A Function Of The Nu...mentioning

confidence: 99%

Design, synthesis, characterization and development of novel organic conducting polymers with technological applications

Aradilla Zapata

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In this thesis, a series of novel organic conducting polymers have been synthesized using alternative methods based on electrochemical techniques, which have allowed to broaden the knowledge in the field of the characterization by means of topological, spectroscopic, electrochemical and structural techniques. Among the variety of synthesis techniques of conducting polymers, layer-by-layer (LbL) has been one of the most important to build multilayered systems. Thus, in this thesis the LbL has shown to be an excellent procedure to explore new applications in the field of energy storage using conducting polymers. On the other hand, recently, the influence of new sustituents on functionalized conducting polymers has been proved to modify the structural, optical and physical properties of conducting polymers. Within this context, synthesis of novel functionalized conducting polymers bearing strong electron-withdrawing sustituents such as cyano group or halide atoms have been widely studied and characterized throughout this thesis. The presence of these substituents have emerged as promising candidates in the field of chemical sensors and electrochromic devices. Although the functionality of polymers or the development of new techniques are excellent procedures to synthesize and to develop new properties on the field of conducting polymers, it is worth mentioning that the substrate plays a crucial role on the electrochemical field. Accordingly, the substrates can also modify and change the properties of conducting polymers during the electropolymerization process. In this way, different substrates were employed in this work with the aim of achieving new applications in the field of corrosion inhibitors and as supercapacitors. Supercapacitors as energy storage device has been an outstanding application during this thesis. Thus, the field of nanotechnology has taken an important part in this thesis through development and design of promising hybrid nanocomposites based on conducting polymers and clay with technological applications and interesting optoelectronic properties. The contribution of theoretical techniques based on quantum mechanical calculations have allowed to predict some electronic and structural properties of conjugated polymers, which could be corroborated experimentally. The quantum mechanics is a useful tool to check experimental results and to understand mechanisms not fully understood at experimental level. Therefore, theoretical calculations have provided promising information to obtain new insights in the field of conducting polymers. La presente tesis se encuentra focalizada en el estudio de nuevos polímeros conductores orgánicos obtenidos a partir de métodos alternativos basados en principios electroquímicos. Entre los principales métodos de polimerización la técnica conocida como capa-a-capa ha emergido con gran fuerza en los últimos años dada sus numerosas ventajas y propiedades. En este contexto, la síntesis de polímeros conductores mediante este procedimiento permitió comprender y analizar el efecto sinérgico entre capas, consiguientemente la caracterización de estos nuevos materiales a partir de técnicas estructurales, espectroscópicas, morfológicas, electroquímicas y ópticas permitió indagar y desarrollar aplicaciones en diferentes campos tecnológicos tales como la electrónica o la corrosión. Otro de los factores que influyen en las propiedades de los polímeros conductores es el proceso de funcionalización. En esta tesis, la incorporación de grupos funcionales con elevado carácter aceptor de electrones centró una parte importante del trabajo, de este modo, los polímeros conductores funcionalizados con átomos halogenados o mediante el grupo ciano evidenciaron una gran influencia en las propiedades físicas, estructurales, ópticas y morfológicas de las estructuras químicas en tiofeno y pirrol. La modificación de determinadas propiedades en estos polímeros permitió desarrollar componentes basados en sensores químicos o dispositivos electrocrómicos. Acorde a esta temática, la modificación de la superficie juega también un papel importante y crucial en las propiedades de los polímeros conductores durante el proceso de síntesis electroquímica. Análogamente al caso de la funcionalización el estudio de la modificación de la superficie denotó una gran expectativa en el desarrollo de nuevos supercondensadores orgánicos, así como una gran alternativa para aplicación como inhibidores de corrosión. Finalmente, en el ámbito experimental de esta tesis, se han orientado estudios en el campo de la nanotecnología en la síntesis y caracterización de nuevos materiales híbridos nanocompuestos con interesantes propiedades optoelectrónicas y electroquímicas. A nivel teórico, la contribución de cálculos teóricos basados en mecánica quántica permitieron predecir determinadas propiedades electrónicas y estructurales de polímeros conductores, cuyos valores fueron corroborados experimentalmente. Así, la química teórica proporcionó un amplio conocimiento en la exploración y comprensión de los mecanismos estructurales de los polímeros conductores.

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“…O primeiro trabalho do grupo sobre esse assunto consistiu na modificação química de nanotubos de carbono de parede simples (single-wall carbon nanotubes -SWCNT) com grupos tiofenos, e sua utilização como receptores de elétrons em células solares orgânicas com poli-3-octiltiofeno (P3OT) [6]. Em seguida vieram os estudos de modificação de SWCNT com cisteamina e nanopartículas de ouro [7] e a utilização da técnica layer-by-layer para o crescimento de filmes multicamadas envolvendo SWCNT e fulerenos modificados [8].…”

Section: Capítulo I -Introdução Geralunclassified

Preparação e caracterização de filmes compósitos contendo nanopartículas de TiO2 e óxido de grafeno reduzido para estudos da foto-oxidação da água e aplicação em células solares

Morais¹

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me deram a essência e me ensinaram a lutar e valorizar as conquistas. Aos meus irmãos, Abelardo Luis de Morais Filho e André Luis de Morais, e ao meu namorado, Bruno Fontes, pelo amor, apoio e incentivos constantes. Vocês sãos as pessoas mais importantes para mim. Dedico esta Tese de Doutorado. vi AGRADECIMENTOS  Primeiramente a Deus, por estar presente em todos os momentos da minha vida, iluminando e protegendo sempre o meu caminho.  À Profa. Dra. Ana Flávia Nogueira pela orientação e confiança, que com profissionalismo e amizade ensinou-me a enfrentar os desafios e a procurar soluções inteligentes para a realização deste trabalho. Obrigada por tudo!  Ao Prof. Dr. James Durrant pela oportunidade de estágio em seu laboratório no Imperial College em Londres, Reino Unido, e pelas medidas de Espectroscopia de Absorção Transiente (TAS).  À Dra. Monica Lira-Cantu pela grandiosa colaboração e por ter me recebido tão bem em seu laboratório no Institut Català de Nanociència i Nanotecnologia (ICN2) em Barcelona, Espanha, durante o período de estágio.  À Profa. Dra. Cláudia Longo pelos ensinamentos e contribuição com ideias para o aprimoramento deste trabalho.  À Profa. Dra. Maria Isabel Felisberti pelo fornecimento de materiais, equipamentos e a possibilidade em trabalhar no seu laboratório e, pelos ensinamentos durante as aulas de Físico-Química do Programa de Estágio Docente.  Ao Helton Pereira Nogueira pela amizade e ajuda durante as primeiras sínteses do óxido de grafite pelo método de Hummer e Offeman modificado.  Ao João Paulo Carvalho Alves pelas medidas de AFM e KPFM além da valiosa amizade e parceria durante a realização desse trabalho  Ao Dr. João Eduardo Benedetti pelas parcerias e medidas de FEG-SEM.  Ao Dr. Emre Yassitepe e Dra. Joyce R. Araujo (Inmetro-RJ) pelas medidas de XPS.  Aos meus queridos amigos do Laboratório de Nanotecnologia e Energia Solar

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Photoelectrochemical, photophysical and morphological studies of electrostatic layer-by-layer thin films based on poly(p-phenylenevinylene) and single-walled carbon nanotubes

Cited by 6 publications

References 44 publications

Evaluation of the photocurrent value for poly(2,5-dicyano- p -phenylene-vinylene)-co-(p-phenylene-vinylene) (DCN-PPV/PPV)

Evaluation of the photocurrent value for poly(2,5-dicyano- p -phenylene-vinylene)-co-(p-phenylene-vinylene) (DCN-PPV/PPV)

Design, synthesis, characterization and development of novel organic conducting polymers with technological applications

Preparação e caracterização de filmes compósitos contendo nanopartículas de TiO2 e óxido de grafeno reduzido para estudos da foto-oxidação da água e aplicação em células solares

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