100 research outputs found

    The cytoskeleton in cell-autonomous immunity: structural determinants of host defence

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    Host cells use antimicrobial proteins, pathogen-restrictive compartmentalization and cell death in their defence against intracellular pathogens. Recent work has revealed that four components of the cytoskeleton — actin, microtubules, intermediate filaments and septins, which are well known for their roles in cell division, shape and movement — have important functions in innate immunity and cellular self-defence. Investigations using cellular and animal models have shown that these cytoskeletal proteins are crucial for sensing bacteria and for mobilizing effector mechanisms to eliminate them. In this Review, we highlight the emerging roles of the cytoskeleton as a structural determinant of cell-autonomous host defence

    P3HT-Based Solar Cells: Structural Properties and Photovoltaic Performance

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    Each year we are bombarded with B.Sc. and Ph.D. applications from students that want to improve the world. They have learned that their future depends on changing the type of fuel we use and that solar energy is our future. The hope and energy of these young people will transform future energy technologies, but it will not happen quickly. Organic photovoltaic devices are easy to sketch, but the materials, processing steps, and ways of measuring the properties of the materials are very complicated. It is not trivial to make a systematic measurement that will change the way other research groups think or practice. In approaching this chapter, we thought about what a new researcher would need to know about organic photovoltaic devices and materials in order to have a good start in the subject. Then, we simplified that to focus on what a new researcher would need to know about poly-3-hexylthiophene:phenyl-C61-butyric acid methyl ester blends (P3HT: PCBM) to make research progress with these materials. This chapter is by no means authoritative or a compendium of all things on P3HT:PCBM. We have selected to explain how the sample fabrication techniques lead to control of morphology and structural features and how these morphological features have specific optical and electronic consequences for organic photovoltaic device applications

    Optically monitored spray coating system for the controlled deposition of the photoactive layer in organic solar cells

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    A spray deposition process equipped with an in situ optical thickness monitoring system has been developed to fabricate the photoactive layer of solar cells. Film thickness is monitored by a photodiode-LED couple after each deposition cycle. Using optimized conditions, the thickness of the spray deposited photoactive films can be tuned to increase linearly with the number of deposition cycles over a wide range of deposition conditions. After instrument calibration, optimization of the active layer thickness can be accomplished by simply setting the desired absorbance of the film. The simple process outlined here may be used for the rapid optimization of thin film photovoltaic devices. As proof of this, we fabricate a poly(3-hexylthiophene-2,5-diyl) (P3HT) and phenyl-C61-butyric acid methyl ester as well as a P3HT and indene-C60 bis-adduct organic solar cells, which achieve a champion power conversion efficiency of 4.2%

    Water-soluble polyfluorenes as an electron injecting layer in PLEDs for extremely high quantum efficiency

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    A cationic water-soluble polyfluorene containing ion-transporting side groups and mobile metal ions is synthesized. The material is used as an electron injection layer in polymer light-emitting diodes with high-work-function Al cathodes. The devices show high quantum efficiencies (see figure), with a maximum external quantum efficiency of 4.8%, approaching the theoretical maximum external quantum efficiency of about 5%.X1167sciescopu

    Manufacturing cost and market potential analysis of demonstrated roll-to-roll perovskite photovoltaic cell processes

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    Perovskite photovoltaic solar cells and modules can be manufactured using roll-to-roll (R2R) techniques, which have the potential for very low cost production. Understanding cost barriers and drivers that will impact its future commercial viability can beneficially guide research directions. Because processes, materials and equipment for manufacturing are still under development, it is difficult to estimate these costs accurately. We use a cost method developed to allow for uncertainty in the input assumptions to analyse three demonstrated R2R compatible manufacturing sequences and two potential optimised sequences. Using these novel methods, we have identified and quantified key cost barriers; high cost materials P3HT and PCBM, the use of evaporation for the rear metal deposition, and the transparent ITO coating. We project that technology developments in these key areas would halve the expected manufacturing cost to US37/m±3037/m±30%. With 68% GFF, 10% PCE and a 3 year lifetime, such R2R perovskite modules would be competitive with existing flexible PV products in the market on a /W and power to weight basis. To compete with Si and CdTe in the flat plate PV market, PCE and lifetimes in excess of 15% and 15 years respectively would be required

    Photonic sintering of copper through the controlled reduction of printed CuO nanocrystals

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    The ability to control chemical reactions using ultrafast light exposure has the potential to dramatically advance materials and their processing toward device integration. In this study, we show how intense pulsed light (IPL) can be used to trigger and modulate the chemical transformations of printed copper oxide features into metallic copper. By varying the energy of the IPL, CuO films deposited from nanocrystal inks can be reduced to metallic Cu via a Cu2O intermediate using single light flashes of 2 ms duration. Moreover, the morphological transformation from isolated Cu nanoparticles to fully sintered Cu films can also be controlled by selecting the appropriate light intensity. The control over such transformations enables for the fabrication of sintered Cu electrodes that show excellent electrical and mechanical properties, good environmental stability, and applications in a variety of flexible devices

    THREE-DIMENSIONAL BULK HETEROJUNCTION MORPHOLOGY FOR ACHIEVING HIGH INTERNAL QUANTUM EFFICIENCY IN POLYMER SOLAR CELLS

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    Here, an investigation of three-dimensional (3D) morphologies for bulk heterojunction (BHJ) films based on regioregular poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C(61)-butyric acid methyl ester (PCBM) is reported Based on the results, it is demonstrated that optimized post-treatment, such as solvent annealing, forces the PCBM molecules to migrate or diffuse toward the top surface of the BHJ composite films, which induces a new vertical component distribution favorable for enhancing the internal quantum efficiency (eta(IQE)) of the devices. To the 3D BHJ morphology, novel time-of-flight secondary-ion mass spectroscopy studies are employed along with conventional methods, such as UV-vis absorption, X-ray diffraction, and high-resolution transmission electron microscopy studies. The eta(IQE) of the devices are also compared after solvent annealing for different times, which performance of BHJ polymer solar cells. In addition, the fabrication of high performance P3HT:PCBM solar cells using the optimized solvent-annealing method is reported, and these cells show a mean power-conversion efficiency of 4.12% under AM 1.5G illumination conditions at an intensity of 100 mW cm(-2).X11174sciescopu

    Toward Large Scale Roll-to-Roll Production of Fully Printed Perovskite Solar Cells

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    Fully printed perovskite solar cells are demonstrated with slot-die coating, a scalable printing method. A sequential slot-die coating process is developed to produce efficient perovskite solar cells and to be used in a large-scale roll-to-roll printing process. All layers excluding the electrodes are printed and devices demonstrate up to 11.96% power conversion efficiency. It is also demonstrated that the new process can be used in roll-to-roll production

    Ultrasonic Velocity and Absorption in RbH 3

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    Back-contacted hybrid organic-inorganic perovskite solar cells

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    © The Royal Society of Chemistry 2016. A novel architecture for quasi-interdigitated electrodes (QIDEs) allows for the fabrication of back-contacted perovskite solar cells. The devices showed a stable power output of 3.2%. The design of the QIDEs avoids the defects that cause short-circuiting in conventional IDEs, while enhancing the collection area of the electrodes. Photoluminescence and photocurrent mapping is used to probe the charge generation and transport properties of the perovskite solar cells
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