40 research outputs found

    Unsettling disciplinary frontiers

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    Recent advances in genetic research provide anthropologists with an opportunity to reconsider the meaning and importance of interdisciplinary research. This piece suggests that interdisciplinary thinking can help to redevelop health policies aimed at improving access to new genetic technology and addressing many health care inequities. Drawing from research on access to genetic testing among women with a breast cancer diagnosis in the United States, I explore how patient perspectives can be used to redefine how policy makers interpret the utility of genetic medicine. Individuals undergoing genetic testing describe how genetic knowledge is translated into salient change in their lives, a view rarely recognized in conventional evaluations of genetic medicine. This work also recognizes how the ‘potentialities’ of genetic medicine both fuel the engine of ongoing genetic research and motivate individuals to imagine possible future actions to improve health. This reflection is meant to provoke debate and contribute to discussion about how health policies can be designed to improve inequities in access to genetic medicine

    MODs vs. NPs: Vying for the Future of Printed Electronics

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    This Minireview compares two distinct ink types, namely metal‐organic decomposition (MOD) and nanoparticle (NP) formulations, for use in the printing of some of the most conductive elements: silver, copper and aluminium. Printing of highly conductive features has found purpose across a broad array of electronics and as processing times and temperatures reduce, the avenues of application expand to low‐cost flexible substrates, materials for wearable devices and beyond. Printing techniques such as screen, aerosol jet and inkjet printing are scalable, solution‐based processes that historically have employed NP formulations to achieve low resistivity coatings printed at high resolution. Since the turn of the century, the rise in MOD inks has vastly extended the range of potentially applicable compounds that can be printed, whilst simultaneously addressing shelf life and sintering issues. A brief introduction to the field and requirements of an ink will be presented followed by a detailed discussion of a wide array of synthetic routes to both MOD and NP inks. Unindustrialized materials will be discussed, with the challenges and outlook considered for the market leaders: silver and copper, in comparison with the emerging field of aluminium inks

    Photovoltaic module energy rating methodology development

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    A consensus-based methodology to calculate the energy output of a PV module will be described in this paper. The methodology develops a simple measure of PV module performance that provides for a realistic estimate of how a module will perform in specific applications. The approach makes use of the weather data profiles that describe conditions throughout the US and emphasizes performance differences between various module types. An industry-representative Technical Review Committee has been assembled to provide feedback and guidance on the strawman and final approach used in developing the methodology

    Deposition of metallic silver from versatile amidinate precursors for use in functional materials

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    Silver (Ag) amidinate metal organic decomposition precursors of the type: [Ag2((ArN)2C(H))2] (Ar = 2,6-dimethylphenyl (1), 2,6-diethylphenyl (2) and 2,6-diisopropylphenyl (3)) have been used for the first time in the deposition of Ag films on glass with multiple functionalities with potential application in optical/biological sensors or for use in electronic circuitry. Precursors 1–3 were isolated from the reaction of silver acetate with the appropriate ligand in a 1:2 stoichiometry and were characterized by 1H and 13C{1H} NMR, thermal gravimetric analysis and single crystal X-ray diffraction for 2. Single-layer depositions at 200 °C on glass substrates via spin coating produced transparent (>90% transmittance) coatings, with well-defined Ag nanoparticles. Multi-layer depositions at 200 °C on glass had a metallic lustre and were found to be conductive ( ρ = 0.916–1.83 × 10−6 Ωm). All films were strongly adhered and displayed excellent coverage of the substrate. Ag films deposited from 1 to 3 were analysed by grazing incidence X-ray diffraction, X-ray photoelectron spectroscopy, energy-dispersive X-ray analysis and scanning electron microscopy, with optical properties determined by UV-Vis spectroscopy

    Tris(β‐ketoiminate) Aluminium(III) Compounds as Aluminium Oxide Precursors

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    Precursor design is the crucial step in tailoring the deposition profile towards a multitude of functional materials. Most commercially available aluminium oxide precursors require high processing temperatures (>500 °C). Herein, we report the tuning of the decomposition profile (200–350 °C) of a range of octahedrally coordinated tris(β-ketoiminate) aluminium complexes of the type [Al(MeCN(R)CHC=OMe)3], by varying the R substituents in the ligands. The complexes are derived from the reaction of trimethylamine alane (TMAA) and a series of N-substituted β-ketoiminate ligands (R-acnacH, R=Me, Et, iPr, Ph) with varying R-substituents sizes. When the more sterically encumbered ligand (R=Mes) was used, the Al atom became five-coordinate, therefore representing the threshold to octahedral coordination around the metal in these type of compounds, which, consequently, lead to a change of decomposition profile. The resulting compounds have been characterised by NMR spectroscopy, mass spectrometry, elemental analysis and single crystal X-ray diffraction. [Al(MeCN(Me)CHC=OMe)3] has been used as a single source precursor for the deposition of Al2O3. Thin films were deposited via aerosol assisted chemical vapour deposition (AACVD), with toluene as the solvent, and were analysed using SEM, EDX and XPS

    Unraveling the Steric Link to Copper Precursor Decomposition: A Multi-Faceted Study for the Printing of Flexible Electronics

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    The field of printed electronics strives for lower processing temperatures to move toward flexible substrates that have vast potential: from wearable medical devices to animal tagging. Typically, ink formulations are optimized using mass screening and elimination of failures; as such, there are no comprehensive studies on the fundamental chemistry at play. Herein, findings which describe the steric link to decomposition profile: combining density functional theory, crystallography, thermal decomposition, mass spectrometry, and inkjet printing, are reported. Through the reaction of copper(II) formate with excess alkanolamines of varying steric bulk, tris-co-ordinated copper precursor ions: "[CuL3 ]," each with a formate counter-ion (1-3) are isolated and their thermal decomposition mass spectrometry profiles are collected to assess their suitability for use in inks (I1-3 ). Spin coating and inkjet printing of I1,2 provides an easily up-scalable method toward the deposition of highly conductive copper device interconnects (ρ = 4.7-5.3 × 10-7 Ω m; ≈30% bulk) onto paper and polyimide substrates and forms functioning circuits that can power light-emitting diodes. The connection among ligand bulk, coordination number, and improved decomposition profile supports fundamental understanding which will direct future design

    Precursors for Atmospheric Plasma-Enhanced Sintering: Low-Temperature Inkjet Printing of Conductive Copper

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    Bidentate diamine and amino-alcohol ligands have been used to form solid, water-soluble, and air-stable monomeric copper complexes of the type [Cu(NH2CH2CH(R)Y)2(NO3)2] (1, R=H, Y=NH2; 2, R=H, Y=OH; 3, R=Me, Y=OH). The complexes were characterized by elemental analysis, mass spectrometry, infrared spectroscopy, thermal gravimetric analysis, and single-crystal X-ray diffraction. Irrespective of their decomposition temperature, precursors 1–3 yield highly conductive copper features [1.5×10−6Ω m (±5×10−7Ω m)] upon atmospheric-pressure plasma-enhanced sintering

    Analysis of initial stabilization of cell efficiency in amorphous silicon photovoltaic modules under real outdoor conditions

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    [EN] This contribution presents a field study in which the initial stabilization of thin-film amorphous silicon (a-Si:H) is investigated. Two grid-connected a-Si:H photovoltaic plants have been monitored and analyzed under real outdoor conditions. A per-unit approach is proposed to compare PV plants with differences in their electrical characteristic and the start-up date. The representation of a normalized per unit PV power versus the accumulated incoming irradiation reveals an evolution that can be characterized through an exposure-response function. By this function, two populations of defects in the cells are detected. It is found that the stabilization process in the first year of operation produces a decrease of 10% in the peak power, equivalent to a decrease of 0.5% in cell efficiency. The use of the accumulated PSH for conducting the analysis of the initial stabilization produces similarities that cannot be obtained if a time scale is used. These results provide a powerful tool for PV plant designers because they enable a prediction to be made of the time-scale stabilization response in terms of unitary power, correlated with the peak sun hours received. (C) 2017 Elsevier Ltd. All rights reserved.This work was supported by Generalitat Valenciana (PROM-ETEOII/2014/059) and Spanish MINECO (Ministry of Economy and Competitiveness TEC2014-53727-C2-1-R).Mateo-Guerrero, C.; Hernåndez Fenollosa, MDLÁ.; Montero Reguera, ÁE.; Segui-Chilet, S. (2018). Analysis of initial stabilization of cell efficiency in amorphous silicon photovoltaic modules under real outdoor conditions. Renewable Energy. 120:114-125. https://doi.org/10.1016/j.renene.2017.12.054S11412512

    Stability, Performance and Trend Modeling of Amorphous Silicon Photovoltaic Modules

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    Design, Synthesis and Solution Studies of Aluminium Precursors for Deposition of Conductive Patterns

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    This work has been carried out in two parts. The first part focuses on the design, synthesis, and isolation of novel aluminium metal-organic decomposition precursors to assess their suitability towards low temperature decomposition to zerovalent aluminium. Emphasis has been placed on elucidating the relationship between the molecular structure of the precursor and its decomposition temperature. The second part is concerned with the spray coating of dimethylethylamine alane to test the propriety of this deposition technique towards obtaining conductive aluminium films. The work is put into context with a broad introduction in Chapter 1, followed by experimental details in Chapter 2. Chapter 3 explores the design and synthesis of novel tris(thioureide) aluminium(III) compounds that exist in octahedral geometry while Chapter 4 describes penta-coordinate bis(thioureide) alkyl aluminium(III) compounds. Thiourea ligands have been utilised with the steric bulk on these varied systematically to evaluate the effect the ligand steric bulk has on the decomposition temperatures of these compounds. The thermal decomposition profiles of these compounds have been assessed via thermal gravimetric analysis and tandem mass spectrometry has been used to look at how these molecules fragment upon collision with nitrogen molecules when heated up to 200 °C. The correlation between the structure of these compounds and their consequent decomposition temperatures has been assessed. The impact of moving from metal-organic compounds to organometallic compounds on the decomposition temperatures has also been evaluated. Chapter 5 is focused on obtaining conductive films of aluminium using dimethylethylamine alane as the precursor and employing the spray-coating deposition technique. Initial studies focused on the deposition of aluminium films onto a variety of substrates. Subsequently, these results were optimised to obtain conductive circuit patterns of aluminium via spray coating for use in solar cells
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