Reconhecemos Paulo JL Webster para a renderização 3D dos dados ópticos com Amira. Phil Muñoz e Benjamin Franta desde comentários sobre o manuscrito todo o seu desenvolvimento. A pesquisa descrita neste trabalho foi apoiado pela Força Aérea, Escritório de Pesquisa Científica em bolsas FA9550-09-1-0546 e FA9550-10-1-0402.

1. Preparando metal-íon Doped filme de polímero <ol><li> Medir 8 ml de água numa proveta. </li><li> Adicionar 206 mg de PVP com a água. Misturar utilizando um agitador magnético ou misturador de vórtice até que a solução fique límpida. </li><li> Adicionar 210 mg de AgNO3 à solução. Misturar utilizando um agitador magnético ou misturador de vórtice até que a solução é límpida. </li><li> Slides revestimento de vidro com solução através da fundição de queda. </li><li> Colocar a lâmina de vidro em um conjunto de forno a 100 ° C. Asse amostra durante 30 minutos. </li><li> Remover a amostra do forno e deixe esfriar por 30 minutos. </li></ol> 2. Fabricação de Estruturas de prata Disconnected <ol><li> Alinhar a configuração ilustrada na Figura 1 na tabela óptica com isoladores de vibração. </li><li> Ajuste compressor para obter 50-FSEC pulsos após objectiva do microscópio. </li><li> Ajustar filtros de densidade neutra para se obter 3-nj pulsos após o objectivo. </li><li> Assegurar o tamanho do ponto laser é maior do que a volta da abertura da objetiva do microscópio. </li><li>Definir modulador acústico-óptico para a produção de vidros de 10 mseg, durante o qual a exposição a amostra é irradiada. </li><li> Bloco de raio laser antes que ele atinja a amostra de microscópio e em lugar de 3 eixos fase de tradução. O percurso do feixe de impulsos de laser femtosegundo deve passar através da objectiva de microscópio de imagem e para a amostra. </li><li> Ligue fonte de iluminação do microscópio para observar a amostra in-situ utilizando a câmara CCD. </li><li> Traduzir eixo z de fase para encontrar de interface entre o substrato de vidro e película de polímero. Então, reorientar microscópio para a profundidade desejada dentro do polímero para a camada inferior mais patterning. Z-tradução durante padronização devem ser na direcção para longe da interface vidro-polímero para evitar a dispersão com estruturas fabricadas. </li><li> Desbloquear feixe de laser e software conjunto controlador de movimento para traduzir amostra em x -, y - e z - direções com velocidade de 100 mm / seg. Irradiar voxels individuais para 10 ms umaª separados voxels vizinhos por pelo menos vários micrômetros para imagens in-situ claro. Definir óptico-acústico taxa de repetição de 25 Hz para modulador irá produzir quatro mícrons espaçamento. Áreas expostas a laser irá conter estruturas de prata. </li></ol>

<ol>
	<li>von Freymann, G., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Three-Dimensional+Nanostructures+for+Photonics.">Three-Dimensional Nanostructures for Photonics.</a> Advanced Functional Materials. 20, 1038-1052 (2010).</li><li>LaFratta, C. N., Fourkas, J. T., Baldacchini, T., Farrer, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Multiphoton+Fabrication.">Multiphoton Fabrication.</a> Angewandte Chemie International Edition. 46, 6238-6258 (2007).</li><li>Gattass, R. R., Mazur, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Femtosecond+laser+micromachining+in+transparent+materials.">Femtosecond laser micromachining in transparent materials.</a> Nat. Photon. 2, 219-225 (2008).</li><li>Li, L., Gattass, R. R., Gershgoren, E., Hwang, H., Fourkas, J. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Achieving+&#955;/20+Resolution+by+One-Color+Initiation+and+Deactivation+of+Polymerization.">Achieving &#955;/20 Resolution by One-Color Initiation and Deactivation of Polymerization.</a> Science. 324, 910-913 (2009).</li><li>Haske, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=65+nm+feature+sizes+using+visible+wavelength+3-D+multiphoton+lithography.">65 nm feature sizes using visible wavelength 3-D multiphoton lithography.</a> Opt. Express. 15, 3426-3436 (2007).</li><li>Xing, J. F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improving+spatial+resolution+of+two-photon+microfabrication+by+using+photoinitiator+with+high+initiating+efficiency.">Improving spatial resolution of two-photon microfabrication by using photoinitiator with high initiating efficiency.</a> Appl. Phys. Lett. 90, 131106 (2007).</li><li>Tan, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reduction+in+feature+size+of+two-photon+polymerization+using+SCR500.">Reduction in feature size of two-photon polymerization using SCR500.</a> Appl. Phys. Lett. 90, 071106 (2007).</li><li>Vora, K., Kang, S., Shukla, S., Mazur, E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Fabrication+of+disconnected+three-dimensional+silver+nanostructures+in+a+polymer+matrix.">Fabrication of disconnected three-dimensional silver nanostructures in a polymer matrix.</a> Appl. Phys. Lett. 100, 063120 (2012).</li><li>G&#252;ney, D. &. #. 2. 1. 4. ;., Koschny, T., Soukoulis, C. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intra-connected+three-dimensionally+isotropic+bulk+negative+index+photonic+metamaterial.">Intra-connected three-dimensionally isotropic bulk negative index photonic metamaterial.</a> Opt. Express. 18, 12348-12353 (2010).</li><li>Grigorenko, A. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nanofabricated+media+with+negative+permeability+at+visible+frequencies.">Nanofabricated media with negative permeability at visible frequencies.</a> Nat. Photon. 438, 335-338 (2005).</li><li>Grigorenko, A. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Negative+refractive+index+in+artificial+metamaterials.">Negative refractive index in artificial metamaterials.</a> Opt. Lett. 31, 2483-2485 (2006).</li><li>Shalaev, V. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Negative+index+of+refraction+in+optical+metamaterials.">Negative index of refraction in optical metamaterials.</a> Opt. Lett. 30, 3356-3358 (2005).</li><li>Ishikawa, A., Tanaka, T., Kawata, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Magnetic+excitation+of+magnetic+resonance+in+metamaterials+at+far-infrared+frequencies.">Magnetic excitation of magnetic resonance in metamaterials at far-infrared frequencies.</a> Appl. Phys. Lett. 91, 113118 (2007).</li><li>Tanaka, T., Ishikawa, A., Kawata, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Two-photon-induced+reduction+of+metal+ions+for+fabricating+three-dimensional+electrically+conductive+metallic+microstructure.">Two-photon-induced reduction of metal ions for fabricating three-dimensional electrically conductive metallic microstructure.</a> Appl. Phys. Lett. 88, 081107 (2006).</li><li>Ishikawa, A., Tanaka, T., Kawata, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improvement+in+the+reduction+of+silver+ions+in+aqueous+solution+using+two-photon+sensitive+dye.">Improvement in the reduction of silver ions in aqueous solution using two-photon sensitive dye.</a> Appl. Phys. Lett. 89, 113102 (2006).</li><li>Cao, Y. -. Y., Takeyasu, N., Tanaka, T., Duan, X. -. M., Kawata, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=3D+Metallic+Nanostructure+Fabrication+by+Surfactant-Assisted+Multiphoton-Induced+Reduction.">3D Metallic Nanostructure Fabrication by Surfactant-Assisted Multiphoton-Induced Reduction.</a> Small. 5, 1144-1148 (2009).</li></ol>

Não há conflitos de interesse declarados.

A chave para o processo é a obtenção de uma matriz dieléctrica dopado que permite a fabricação de alta resolução, mas não se degrada mais rapidamente após a preparação. Uma mistura simples de PVP, AgNO 3 e H 2 O permite a criação de nanoestruturas de alta resolução de prata que estão incorporados no interior de uma matriz de suporte. Variando a proporção de PVP de AgNO 3 irá alterar a energia de laser necessária para a fabricação, e outras propriedades, tais como p...

a method to fabricate disconnected silver nanostructures in 3d

O kit de ferramentas inclui técnicas de nanofabricação padrão principalmente destinadas a criar padrões 2D em meios dielétricos. Criando padrões de metal em uma escala submicron requer uma combinação de ferramentas nanofabricação e vários passos de processamento do material. Por exemplo, os passos para criar estruturas metálicas planas usando fotolitografia ultravioleta e litografia por feixe de elétrons podem incluir a exposição da amostra, desenvolvimento da amostra, a deposição de metal e decolagem metal. Para criar estruturas metálicas em 3D, a sequência é repetida várias vezes. A complexidade e dificuldade de empilhamento e alinhamento de camadas múltiplas limita implementações práticas de estruturação de metal 3D usando ferramentas de nanofabricação padrão. Laser femtosegundo escrita direta surgiu como uma técnica de pré-eminente de nanofabricação 3D. 1,2 lasers de femtossegundos são freqüentemente usados ​​para criar padrões 3D em polímeros e vidros. 3-7 No entanto, metal 3D direto escrever permanece um desafio. Aqui, nósdescrevem um método para o fabrico de nanoestruturas de prata embutido no interior de uma matriz de polímero usando um laser de femtosegundos centrado em 800 nm. O método permite a fabricação de padrões não viáveis ​​utilizando outras técnicas, tais como matrizes 3D de voxels prata desconectadas. 8 desconectados padrões de metal 3D são úteis para células unitárias metamateriais onde não estão em contacto uns com os outros, tais como o metal 9 acoplado ponto 10, 11 ou acoplado haste de metal 12,13 ressoadores. As aplicações potenciais incluem metamateriais índice negativo, capas de invisibilidade, e lentes perfeitas. Em femtosegundo laser de escrita directa, o comprimento de onda do laser é escolhido de tal modo que não são linearmente fotões absorvidos no meio-alvo. Quando a duração do pulso de laser é comprimida para a escala de tempo de femtossegundos e a radiação é fortemente centrado no interior do alvo, a intensidade extremamente elevado induz a absorção não-linear. Fotões são absorvidos vários simultânealy para causar transições electrónicas que levam a alterações significativas na região focada. Utilizando esta abordagem, pode-se formar estruturas na massa de um material, em vez de na sua superfície. A maioria dos trabalhos sobre a escrita de metal 3D direto tem focado na criação de estruturas de auto-suporte de metal. 14-16 O método descrito aqui produz estruturas sub-micrométricas de prata que não precisam de ser auto-suportadas porque estão embutidos dentro de uma matriz. Um polímero dopado matriz é preparado utilizando uma mistura de nitrato de prata (AgNO3), polivinilpirrolidona (PVP) e de água (H2O). As amostras são então modelado por irradiação com um laser de femtosegundos 11-MHz produzir 50-fs pulsos. Durante a irradiação, fotoredução de iões de prata é induzida através da absorção não-linear, a criação de um agregado de nanopartículas de prata, na região focal. Usando essa abordagem, criar padrões de prata incorporados em um PVP dopado matriz. Adicionando tradução em 3D do samplo estende o padrão para três dimensões.

O modulador acústico-óptico e filtros de densidade neutra (Figura 1) permitem controlar a quantidade de energia depositada na amostra. Usando uma exposição de 110 impulsos por voxel e nJ 3 por impulsos, com a etapa de conversão em 100 um / segundo, as estruturas de prata resultantes são facilmente visíveis por microscopia óptica in-situ. Níveis mais baixos de laser de exposição (reduzindo a energia de pulso e / ou o número de impulsos) de chumbo para características menores prata,....

Watch this Scientific Journal Video about A Method to Fabricate Disconnected Silver Nanostructures in 3D at JoVE.com

A Method to Fabricate Disconnected Silver Nanostructures in 3D

Laser femtosegundo escrita direta é freqüentemente usado para criar tridimensionais (3D) em polímeros padrões e óculos. No entanto, os metais de padronização em 3D continua a ser um desafio. Descreve-se um método para a fabricação de nanoestruturas de prata embutido no interior de uma matriz de polímero usando um laser de femtosegundos centrado em 800 nm.

Um método para fabricar nanoestruturas de prata desconectados em 3D

The standard nanofabrication toolkit includes  techniques primarily aimed at creating 2D patterns in dielectric media. Creating  metal patterns on a ...

a-method-to-fabricate-disconnected-silver-nanostructures-in-3d

Research

JoVE Journal

Engineering

13.7K visualizações.  Harvard University. Laser femtosegundo escrita direta é freqüentemente usado para criar tridimensionais (3D) em polímeros padrões e óculos. No entanto, os metais de padronização em 3D continua a ser um desafio. Descreve-se um método para a fabricação de nanoestruturas de prata embutido no interior de uma matriz de polímero usando um laser de femtosegundos centrado em 800 nm.

Vídeo: A Method to Fabricate Disconnected Silver Nanostructures in 3D

Evaluating Plasmonic Transport in Current-carrying Silver Nanowires

Plasmonics is an emerging technology capable of simultaneously transporting a plasmonic signal and an electronic signal on the same information support1,2,3. In this context, metal nanowires are especially desirable for realizing dense routing networks4. A prerequisite to operate such shared nanowire-based platform relies on our ability to electrically contact individual metal nanowires and efficiently excite surface plasmon polaritons5 in this information support. In this article, we describe a protocol to bring electrical terminals to chemically-synthesized silver nanowires6 randomly distributed on a glass substrate7. The positions of the nanowire ends with respect to predefined landmarks are precisely located using standard optical transmission microscopy before encapsulation in an electron-sensitive resist. Trenches representing the electrode layout are subsequently designed by electron-beam lithography. Metal electrodes are then fabricated by thermally evaporating a Cr/Au layer followed by a chemical lift-off. The contacted silver nanowires are finally transferred to a leakage radiation microscope for surface plasmon excitation and characterization8,9. Surface plasmons are launched in the nanowires by focusing a near infrared laser beam on a diffraction-limited spot overlapping one nanowire extremity5,9. For sufficiently large nanowires, the surface plasmon mode leaks into the glass substrate9,10. This leakage radiation is readily detected, imaged, and analyzed in the different conjugate planes in leakage radiation microscopy9,11. The electrical terminals do not affect the plasmon propagation. However, a current-induced morphological deterioration of the nanowire drastically degrades the flow of surface plasmons. The combination of surface plasmon leakage radiation microscopy with a simultaneous analysis of the nanowire electrical transport characteristics reveals the intrinsic limitations of such plasmonic circuitry.

Silver nanowires can simultaneously transport electrons and optical information in the form of surface plasmons. A procedure is described here to realize such a shared circuitry and the limitations at propagating both information carriers are evaluated.

Avaliando plasmônicos Transporte em Prata atual de transporte de nanofios

Plasmonics is an emerging technology capable of simultaneously transporting a plasmonic signal and an electronic signal on the same information ...

Engenharia

Writing and Low-Temperature Characterization of Oxide Nanostructures

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions. Oxide interfaces exhibit a wide range of properties that can be controlled include conduction, piezoelectric behavior, ferromagnetism, superconductivity and nonlinear optical properties. Recently, methods for controlling these properties at extreme nanoscale dimensions have been discovered and developed. Here are described explicit step-by-step procedures for creating LaAlO3/SrTiO3 nanostructures using a reversible conductive atomic force microscopy technique. The processing steps for creating electrical contacts to the LaAlO3/SrTiO3 interface are first described. Conductive nanostructures are created by applying voltages to a conductive atomic force microscope tip and locally switching the LaAlO3/SrTiO3 interface to a conductive state. A versatile nanolithography toolkit has been developed expressly for the purpose of controlling the atomic force microscope (AFM) tip path and voltage. Then, these nanostructures are placed in a cryostat and transport measurements are performed. The procedures described here should be useful to others wishing to conduct research in oxide nanoelectronics.

Oxide nanostructures provide new opportunities for science and technology. The interfacial conductivity between LaAlO3 and SrTiO3 can be controlled with near-atomic precision using a conductive atomic force microscopy technique. The protocol for creating and measuring conductive nanostructures at LaAlO3/SrTiO3 interfaces is demonstrated.

Escrita e Caracterização baixa temperatura de óxido de Nanoestruturas

Oxide nanoelectronics is a rapidly growing field which seeks to develop novel materials with multifunctional behavior at nanoscale dimensions.  Oxide ...

Ohmic Contact Fabrication Using a Focused-ion Beam Technique and Electrical Characterization for Layer Semiconductor Nanostructures

Layer semiconductors with easily processed two-dimensional (2D) structures exhibit indirect-to-direct bandgap transitions and superior transistor performance, which suggest a new direction for the development of next-generation ultrathin and flexible photonic and electronic devices. Enhanced luminescence quantum efficiency has been widely observed in these atomically thin 2D crystals. However, dimension effects beyond quantum confinement thicknesses or even at the micrometer scale are not expected and have rarely been observed. In this study, molybdenum diselenide (MoSe2) layer crystals with a thickness range of 6-2,700 nm were fabricated as two- or four-terminal devices. Ohmic contact formation was successfully achieved by the focused-ion beam (FIB) deposition method using platinum (Pt) as a contact metal. Layer crystals with various thicknesses were prepared through simple mechanical exfoliation by using dicing tape. Current-voltage curve measurements were performed to determine the conductivity value of the layer nanocrystals. In addition, high-resolution transmission electron microscopy, selected-area electron diffractometry, and energy-dispersive X-ray spectroscopy were used to characterize the interface of the metal&#8211;semiconductor contact of the FIB-fabricated MoSe2 devices. After applying the approaches, the substantial thickness-dependent electrical conductivity in a wide thickness range for the MoSe2-layer semiconductor was observed. The conductivity increased by over two orders of magnitude from 4.6 to 1,500 &#937;&#8722;1 cm&#8722;1, with a decrease in the thickness from 2,700 to 6 nm. In addition, the temperature-dependent conductivity indicated that the thin MoSe2 multilayers exhibited considerably weak semiconducting behavior with activation energies of 3.5-8.5 meV, which are considerably smaller than those (36-38 meV) of the bulk. Probable surface-dominant transport properties and the presence of a high surface electron concentration in MoSe2 are proposed. Similar results can be obtained for other layer semiconductor materials such as MoS2 and WS2.

We describe the approaches for the device fabrication and electrical characterization of molybdenum diselenide (MoSe2) layer semiconductor nanostructures with different thicknesses. In addition, the fabrication of ohmic contacts for MoSe2-layer nanocrystals by the focused-ion beam deposition method using platinum (Pt) as a contact metal is described.

Ohmic Contato Fabrication usando uma técnica Focused-ion Beam e caracterização elétrica para camada semicondutora Nanoestruturas

Layer semiconductors with easily processed two-dimensional (2D) structures exhibit indirect-to-direct bandgap transitions and superior transistor ...

Integration of Light Trapping Silver Nanostructures in Hydrogenated Microcrystalline Silicon Solar Cells by Transfer Printing

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly known as plasmonic effects, play an important role. Research in this field has, however, been impeded owing to the difficulty of fabricating devices containing the desired functional metal nanostructures. In order to provide a viable strategy to this issue, we herein show a transfer printing-based approach that allows the quick and low-cost integration of designed metal nanostructures with a variety of device architectures, including solar cells. Nanopillar poly(dimethylsiloxane) (PDMS) stamps were fabricated from a commercially available nanohole plastic film as a master mold. On this nanopatterned PDMS stamps, Ag films were deposited, which were then transfer-printed onto block copolymer (binding layer)-coated hydrogenated microcrystalline Si (&#181;c-Si:H) surface to afford ordered Ag nanodisk structures. It was confirmed that the resulting Ag nanodisk-incorporated &#181;c-Si:H solar cells show higher performances compared to a cell without the transfer-printed Ag nanodisks, thanks to plasmonic light trapping effect derived from the Ag nanodisks. Because of the simplicity and versatility, further device application would also be feasible thorough this approach.

A viable transfer printing-based methodology to introduce plasmonic metal nanostructures in solar cells is described. Using nanopillar poly(dimethylsiloxane) stamps, an Ag-based ordered nanodisk array was integrated with standard hydrogenated microcrystalline Si solar cells, which led to improved device performances due to plasmonic light trapping.

Integração da luz Interceptação de prata Nanoestruturas em células solares de silício hidrogenado microcristalina por Transferência de impressão

One of the potential applications of metal nanostructures is light trapping in solar cells, where unique optical properties of nanosized metals, commonly ...

A Fabrication Method for Highly Stretchable Conductors with Silver Nanowires

Stretchable electronics are identified as a key technology for electronic applications in the next generation. One of the challenges in fabrication of stretchable electronic devices is the preparation of stretchable conductors with great mechanical stability. In this study, we developed a simple fabrication method to chemically solder the contact points between silver nanowire (AgNW) networks. AgNW nanomesh was first deposited on a glass slide via spray coating method. A reactive ink composed of silver nanoparticle (AgNPs) precursors was applied over the spray coated AgNW thin films. After heating for 40 min, AgNPs were preferentially generated over the nanowire junctions to solder the AgNW nanomesh, and reinforced the conducting network. The chemically modified AgNW thin film was then transferred to polyurethane (PU) substrates by casting method. The soldered AgNW thin films on PU exhibited no obvious change in electrical conductivity under stretching or rolling process with elongation strains up to 120%.

A simple synthesis method is used to chemically solder silver nanowire thin film to fabricate highly stretchable and conductive metal conductors.

Um método de fabricação para Condutores altamente extensível com prata Nanowires

Stretchable electronics are identified as a key technology for electronic applications in the next generation. One of the challenges in fabrication of ...

Challenges in Rheological Characterization of Highly Concentrated Suspensions &#8212; A Case Study for Screen-printing Silver Pastes

A comprehensive rheological characterization of highly concentrated suspensions or pastes is mandatory for a targeted product development meeting the manifold requirements during processing and application of such complex fluids. In this investigation, measuring protocols for a conclusive assessment of different process relevant rheological parameters have been evaluated. This includes the determination of yield stress, viscosity, wall slip velocity, structural recovery after large deformation and elongation at break as well as tensile force during filament stretching.
The importance of concomitant video recordings during parallel-plate rotational rheometry for a significant determination of rheological quantities is demonstrated. The deformation profile and flow field at the sample edge can be determined using appropriate markers. Thus, measurement parameter settings and plate roughness values can be identified for which yield stress and viscosity measurements are possible. Slip velocity can be measured directly and measuring conditions at which plug flow, shear banding or sample spillover occur can be identified clearly. 
Video recordings further confirm that the change in shear moduli observed during three stage oscillatory shear tests with small deformation amplitude in stage I and III but large oscillation amplitude in stage II can be directly attributed to structural break down and recovery. For the pastes investigated here, the degree of irreversible, shear-induced structural change increases with increasing deformation amplitude in stage II until a saturation is reached at deformations corresponding to the crossover of G' and G'', but the irreversible damage is independent of the duration of large amplitude shear. 
A capillary breakup elongational rheometer and a tensile tester have been used to characterize deformation and breakup behavior of highly filled pastes in uniaxial elongation. Significant differences were observed in all experiments described above for two commercial screen-printing silver pastes used for front side metallization of Si-solar cells.

Challenges in Rheological Characterization of Highly Concentrated Suspensions &amp;#8212; A Case Study for Screen-printing Silver Pastes

A protocol for a robust and application relevant rheological characterization of highly concentrated suspensions is presented. Silver pastes used for screen-printing application in solar cell production are employed as model systems.

Desafios na reológico Caracterização de suspensões altamente concentrado - um estudo de caso para-impressão da tela de prata Cola

A comprehensive rheological characterization of highly concentrated suspensions or pastes is mandatory for a targeted product development meeting the ...

A Standard and Reliable Method to Fabricate Two-Dimensional Nanoelectronics

Two-dimensional (2D) materials have attracted huge attention due to their unique properties and potential applications. Since wafer scale synthesis of 2D materials is still in nascent stages, scientists cannot fully rely on traditional semiconductor techniques for related research. Delicate processes from locating the materials to electrode definition need to be well controlled. In this article, a universal fabrication protocol required in manufacturing nanoscale electronics, such as 2D quasi-heterojunction bipolar transistors (Q-HBT), and 2D back-gated transistors are demonstrated. This protocol includes the determination of material position, electron beam lithography (EBL), metal electrode definition, et al. A step by step narrative of the fabrication procedures for these devices are also presented. Furthermore, results show that each of the fabricated devices has achieved high performance with high repeatability. This work reveals a comprehensive description of process flow for preparing 2D nano-electronics, enables the research groups to access this information, and pave the way toward future electronics.

The article aims to introduce a standard and reliable fabrication procedure for the development of future low dimensional nanoelectronics.

Um método padrão e confiável para fabricar nanoelectrónica bidimensional

Two-dimensional (2D) materials have attracted huge attention due to their unique properties and potential applications. Since wafer scale synthesis of 2D ...

Fabrication of Robust Nanoscale Contact between a Silver Nanowire Electrode and CdS Buffer Layer in Cu(In,Ga)Se2 Thin-film Solar Cells

Silver nanowire transparent electrodes have been employed as window layers for Cu(In,Ga)Se2 thin-film solar cells. Bare silver nanowire electrodes normally result in very poor cell performance. Embedding or sandwiching silver nanowires using moderately conductive transparent materials, such as indium tin oxide or zinc oxide, can improve cell performance. However, the solution-processed matrix layers can cause a significant number of interfacial defects between transparent electrodes and the CdS buffer, which can eventually result in low cell performance. This manuscript describes how to fabricate robust electrical contact between a silver nanowire electrode and the underlying CdS buffer layer in a Cu(In,Ga)Se2 solar cell, enabling high cell performance using matrix-free silver nanowire transparent electrodes. The matrix-free silver nanowire electrode fabricated by our method proves that the charge-carrier collection capability of silver nanowire electrode-based cells is as good as that of standard cells with sputtered ZnO:Al/i-ZnO as long as the silver nanowires and CdS have high-quality electrical contact. The high-quality electrical contact was achieved by depositing an additional CdS layer as thin as 10 nm onto the silver nanowire surface.

Fabrication of Robust Nanoscale Contact between a Silver Nanowire Electrode and CdS Buffer Layer in CuIn,GaSe2 Thin-film Solar Cells

In this protocol, we describe the detailed experimental procedure for the fabrication of a robust nanoscale contact between a silver nanowire network and CdS buffer layer in a CIGS thin-film solar cell.

Fabricação do contato de nanoscale robusto entre um elétrodo de nanowire de prata e a camada do amortecedor dos CdS em células solares do fino-filme do se2 de UC (em, GA)

Silver nanowire transparent electrodes have been employed as window layers for Cu(In,Ga)Se2 thin-film solar cells. Bare silver nanowire electrodes ...

Spectral and Angle-Resolved Magneto-Optical Characterization of Photonic Nanostructures

Photonic crystals are periodic nanostructures that can support a variety of confined electromagnetic modes. Such confined modes are usually accompanied by local enhancement of electric field intensity that strengthens light-matter interactions, enabling applications such as surface-enhanced Raman scattering (SERS) and surface plasmon enhanced sensing. In the presence of magneto-optically active materials, the local field enhancement gives rise to anomalous magneto-optical activity. Typically, the confined modes of a given photonic crystal depend strongly on the wavelength and incidence angle of the incident electromagnetic radiation. Thus, spectral and angular-resolved measurements are needed to fully identify them as well as to establish their relationship with the magneto-optical activity of the crystal. In this article, we describe how to use a Fourier-plane (back focal plane) microscope to characterize magneto-optically active samples. As a model system, here we use a plasmonic grating built out of magneto-optically active Au/Co/Au multilayer. In the experiments, we apply a magnetic field on the grating in situ and measure its reciprocal space response, obtaining the magneto-optical response of the grating over a range of wavelengths and incident angles. This information enables us to build a complete map of the plasmonic band structure of the grating and the angle and wavelength dependent magneto-optical activity. These two images allow us to pinpoint the effect that the plasmon resonances have on the magneto-optical response of the grating. The relatively small magnitude of magneto-optical effects requires a careful treatment of the acquired optical signals. To this end, an image processing protocol for obtaining magneto-optical response from the acquired raw data is laid out.

Photonic band structure enables understanding how confined electromagnetic modes propagate within a photonic crystal. In photonic crystals that incorporate magnetic elements, such confined and resonant optical modes are accompanied by enhanced and modified magneto-optical activity. We describe a measurement procedure to extract the magneto-optical band structure by Fourier space microscopy.

Caracterização magneto-óptica espectral e de ângulo-resolvido de nanoestruturas fotônicas

Photonic crystals are periodic nanostructures that can support a variety of confined electromagnetic modes. Such confined modes are usually accompanied by ...

Macro-Rheology Characterization of Gill Raker Mucus in the Silver Carp, Hypophthalmichthys molitrix

The silver carp, Hypophthalmichthys molitrix, is an invasive planktivorous filter feeder fish that infested the natural waterways of the upper Mississippi River basin due to its highly efficient filter feeding mechanism. The characteristic organs called gill rakers (GRs), found in many such filter feeders, facilitate the efficient filtration of food particles such as phytoplankton that are of a few microns in size.
The motivation to investigate the rheology of the GR mucus stems from our desire to understand its role in aiding the filter feeding process in the silver carp. The mucus-rich fluid, in a &#8216;thick and sticky&#8217; state may facilitate the adhesion of food particulates. The permeation and transport through the GR membrane are&#160;facilitated by the action of external shear forces that induce varying shear strain rates. Therefore, mucus rheology can provide a vital clue to the tremendous outcompeting nature of the silver carp within the pool of filter feeding fish. Based on this it was posited that GR mucus may provide an adhesive function to food particles and act as a transport vehicle to assist in the filter feeding process.
The main objective of the protocol is to determine the yield stress of the mucus, attributed to the minimum shear stress required to initiate flow at which irreversible plastic deformation is first observed across a structured viscoelastic material. Accordingly, rheological properties of the GR mucus, i.e., viscosity, storage, and loss moduli, were investigated for its non-Newtonian, shear-thinning nature using a rotational rheometer. &#160;
A protocol presented here is employed to analyze the rheological properties of mucus extracted from the gill rakers of a silver carp, fished at Hart Creek location of the Missouri River. The protocol aims to develop an effective strategy for rheological testing and material characterization of mucus assumed to be a structured viscoelastic material.

Macro-Rheology Characterization of Gill Raker Mucus in the Silver Carp, Hypophthalmichthys molitrix

This protocol presents a method to perform rheology characterization of mucus that resides on gill rakers (GRs) of the silver carp. Viscoelastic characteristics of GR-mucus, obtained by measuring viscosity, storage and loss moduli, are evaluated for the apparent yield stress to understand the filter feeding mechanism in GRs.

Caracterização macro-reologia de Gill Raker Mucus na Carpa de Prata, Hipophthalmichthys molitrix

The silver carp, Hypophthalmichthys molitrix, is an invasive planktivorous filter feeder fish that infested the natural waterways of the upper Mississippi ...