Carbon nanotubes based nanocomposites for photocurrent improvement

Canestraro, Carla Daniele; Schnitzler, Mariane C.; Zarbin, Aldo J. G.; Luz, M. G. E. da; Roman, Lucimara S.

doi:10.1016/j.apsusc.2005.12.139

Cited by 42 publications

(30 citation statements)

References 16 publications

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“…For example, we demonstrated individually addressable photo-switches by integrating PPy nanoarches within a pattern of Au electrodes. Figure 4 a shows three nanoarches ( r ∼ 260 nm; length: ∼ 20 μ m) with different concentrations of multi-wall carbon nanotubes (MWNT, an electron acceptor), [ 23 ] bridging Au electrodes separated by a 5 μ m gap.…”

Section: Three-dimensional Writing Of Conducting Polymer Nanowire Arrmentioning

confidence: 99%

Three‐Dimensional Writing of Conducting Polymer Nanowire Arrays by Meniscus‐Guided Polymerization

et al. 2011

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Organic electronics increasingly impacts our everyday life with a variety of devices such as displays for TV or mobile appliances, smart cards and radio-frequency identifi cation (RFID) tags. [ 1 , 2 ] This blossoming domain could greatly profi t from effective ways to fabricate conducting or semiconducting organic nanowires. [ 3 ] Specifi cally, the three-dimensional (3D) and individual integration of each nanowire is essential [ 4 ] for many new device concepts, but so far this was not possible. Here we show the demonstration of accurate and versatile 3D direct writing of conducting polymer nanowires based on guiding a monomer meniscus by pulling a micropipette during oxidative polymerization. This is an important step for organic electronic integration with high density and enhanced freedom in circuit design.Conducting polymers such as polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) are very interesting materials because they combine tunable electrical transport characteristics and excellent mechanical properties. [ 5 ] In particular, conducting polymer nanowires are quite important for a broad range of nanodevices such as fi eld effect transistors, [ 3 ] bio-and chemical sensors, [ 6 , 7 ] and non-volatile memories. [ 8 ] Such nanowires are fabricated by soft lithography, [ 9 , 10 ] dip-pen lithography [ 11 ] and electrospinning. [ 12 ] However, these methods are still limited to in-plane patterning of low-aspect-ratio nanowires, whereas for advanced applications 3D patterning is essential.Direct ink writing and probe-based drawing are used for 3D wire patterning. The fi rst method, based on the extrusion of concentrated ink through a nozzle, was applied for 3D microfabrication with metals, oxides, and polymers. [13][14][15][16] However, bringing the wire diameter below micrometer-level is not easy due to the size and concentration of the ink particles. Probe-based drawing can fabricate polymer nanowires. [ 17 ] However, high-density integration is limited by the large pre-deposited polymer droplet (a few tens to hundreds of micrometers).An alternate technique for 3D electrodeposition was recently developed: writing nanowires with a nanoscale electrolyte meniscus. [ 18 , 19 ] This method was so far demonstrated for 3D metallic nanowires but not for conducting polymers.Here we show that this type of technique can in fact be used for conducting polymers offering high accuracy, excellent versatility and marked advantages with respect to alternate solutions. In essence, we obtained a stretched monomer meniscus by pulling a micropipette fi lled with a Py solution, exploiting oxidative polymerization in air. The wire radius so produced was accurately controlled down to ∼ 50 nm by tuning the pulling speed.The technique was successfully tested with specifi c focus on essential features for advanced organic nanodevice integration. Specifi cally, we produced dense arrays of different types of freestanding nanocomponents: straight wires, complex-shape wires, branche...

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Section: Three-dimensional Writing Of Conducting Polymer Nanowire Arrmentioning

confidence: 99%

Three‐Dimensional Writing of Conducting Polymer Nanowire Arrays by Meniscus‐Guided Polymerization

et al. 2011

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“…For instance, photovoltaic cells based on a poly(3-hexylthiophene)/CNT composite as the active layer have a 340% higher efficiency for the conversion of photons to electrons than a similar device made of pristine polymers [18]. Polyaniline (PANI) has been used in the synthesis of polymer/CNT/metal nanocomposites, which have applications in electronic devices [19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Coating of multiwalled carbon nanotubes with polymer nanospheres through microemulsion polymerization

Reddy

Sin²,

Yoo

et al. 2009

Journal of Colloid and Interface Science

146

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“…24 This is a very interesting and specific CNT sample because it presents magnetic properties due to the ironbased fillers. 25 The specific synergistic combination of the electrical and mechanical CNT-based properties and the optical and magnetic iron and iron oxide properties result in an unusual multifunctional material, which has been widely used in our research group as a gas sensor and in electrical memory devices, 26 as a filler in organic photovoltaic devices, 27 in conducting-polymers and metal nanoparticlebased nanocomposites, 28,29 and in electrochemical electrodes. 30 For many of these applications, specific chemical treatments must be performed first in order to remove impurities, add functionalities and/or stabilize the CNT dispersion.…”

Section: Introductionmentioning

confidence: 99%

The effect of different chemical treatments on the structure and stability of aqueous dispersion of iron- and iron oxide-filled multi-walled carbon nanotubes

Moraes¹,

Matos²,

Castro³

et al. 2011

J. Braz. Chem. Soc.

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O efeito de cinco diferentes tratamentos químicos (HNO 3 , H 2 SO 4 , H 2 O 2 , HNO 3 + H 2 SO 4 e HNO 3 + HCl) na homogeneidade, superfície, estrutura e dispersabilidade em água de nanotubos de carbono do tipo multi-paredes preenchidos com ferro ou óxido de ferro foi estudado através de difratometria de raios X (XRD), espectroscopias Raman, UV-Visível e fotoeletrônica de raios X (XPS), análise termogravimétrica (TG) e microscopia eletrônica de varredura (MEV). Os resultados indicaram que os tratamentos são efetivos na remoção de espécies carbonáceas diferentes de nanotubos, presentes na amostra. Com exceção do tratamento com H 2 O 2 , uma boa remoção das espécies contendo metal também foi observada. Além de aumentar a homogeneidade das amostras, os tratamentos também criam grupos carboxílicos e hidroxílicos superficiais, que afetam diretamente a dispersabilidade destas espécies em água. Dispersões estáveis de 2,24 × 10 -1 g L -1 de nanotubos em água foram obtidas após o tratamento com mistura de ácido sulfúrico e ácido nítrico.The effect of five different chemical treatments (HNO 3 , H 2 SO 4 , H 2 O 2 , HNO 3 + H 2 SO 4 and HNO 3 + HCl) on the homogeneity, surface chemistry, structure and dispersibility in water of ironand iron oxide-filled multi-walled carbon nanotube samples was evaluated by X-ray diffractometry (XRD), Raman, UV-Visible and X-ray photoelectron (XPS) spectroscopies, thermogravimetric analysis (TG) and scanning electron microscopy (SEM). The results indicate that the chemical treatments are generally effective in removing non-nanotube carbonaceous species present in the sample. With the exception of the H 2 O 2 treatment, the chemical treatments also offer good removal of free iron-species. Besides the increase in the sample homogeneity, the chemical treatments promoted an increase in the carboxyl and hydroxyl groups at the carbon nanotube surface, what directly affects the dispersibility of these carbon nanotubes in water. Dispersions of 2.24 × 10 -1 g L -1were obtained for the treated samples with a mixture of nitric and sulfuric acid. Keywords: carbon nanotubes, chemical treatment, CVD, nanostructures, nanomaterials IntroductionCarbon nanotubes (CNTs) have received much attention in the last years due to their extraordinary chemical and physical properties, arising from the combination of their typical morphology, structure and size.1 Many different processes have been described for the synthesis of CNTs. Among them, one of the most versatile is the catalytic chemical vapor deposition (CVD), which is based on the decomposition of a carbon source (usually a hydrocarbon) over metal nanocatalysts.2 Usually, the resulting samples are a mixture of CNTs and some impurities, such as other carbonaceous materials (graphite, amorphous carbon, fullerenes, carbon nano-structures, etc.) and the catalyst metal particles.3 These impurities are undesirable for a variety of applications, and different physical and/or chemical treatments are usually performed to remove them. 4 However, it should be noted th...

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Carbon nanotubes based nanocomposites for photocurrent improvement

Cited by 42 publications

References 16 publications

Three‐Dimensional Writing of Conducting Polymer Nanowire Arrays by Meniscus‐Guided Polymerization

Three‐Dimensional Writing of Conducting Polymer Nanowire Arrays by Meniscus‐Guided Polymerization

Coating of multiwalled carbon nanotubes with polymer nanospheres through microemulsion polymerization

The effect of different chemical treatments on the structure and stability of aqueous dispersion of iron- and iron oxide-filled multi-walled carbon nanotubes

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