Position‐Sensitive Array Photodetector Based on Comb‐Like CdS Nanostructure with Cone‐Shape Branches

2D microscale position‐sensitive detectors (PSDs) are highly desirable with the degree of integration increase and the size reduction of nanodevices, which are still unavailable. Multichannel devices with outstanding photoelectric properties attract considerable interest as powerful building blocks to be applied in on‐chip systems. Here, based on a highly ordered comb‐like CdS nanowire array with cone‐shape branches through a one‐step synthesis strategy, a high‐resolution 2D position‐sensitive photodetector is realized through variable resistance in different transportation routes and variable optical responses at different parts of the cone‐shape branches, which enable accurate position identification of incident light in various zones of nanowire arrays according to photocurrent changes. In a broadband from 310 to 560 nm, the PSD exhibits high sensitivity with 85 and 58 KΩ µm^?1 in the trunk and branch part, respectively, and an ultrafast optical response shorter than tens of millisecond. Moreover, a lower conductivity change rate per unit temperature of the PSD (1.625 × 10^?9 A V^?1 K^?1) than that of commercial Si‐based PSDs (≈6.67 × 10^?7 A V^?1 K^?1) reveals outstanding low‐temperature performance. Finally, the multichannel nanostructure based PSD with nanoscale resolution is applied to high‐accuracy quadrant photodetectors.     

The Role of Bulk and Interface Recombination in High‐Efficiency Low‐Dimensional Perovskite Solar Cells

2D Ruddlesden–Popper perovskite (RPP) solar cells have excellent environmental stability. However, the power conversion efficiency (PCE) of RPP cells remains inferior to 3D perovskite‐based cells. Herein, 2D (CH₃(CH₂)₃NH₃)₂(CH₃NH₃)_n?1Pb_nI_3n+1 perovskite cells with different numbers of [PbI₆]^4? sheets (n = 2–4) are analyzed. Photoluminescence quantum yield (PLQY) measurements show that nonradiative open‐circuit voltage (V_OC) losses outweigh radiative losses in materials with n > 2. The n = 3 and n = 4 films exhibit a higher PLQY than the standard 3D methylammonium lead iodide perovskite although this is accompanied by increased interfacial recombination at the top perovskite/C₆₀ interface. This tradeoff results in a similar PLQY in all devices, including the n = 2 system where the perovskite bulk dominates the recombination properties of the cell. In most cases the quasi‐Fermi level splitting matches the device V_OC within 20 meV, which indicates minimal recombination losses at the metal contacts. The results show that poor charge transport rather than exciton dissociation is the primary reason for the reduction in fill factor of the RPP devices. Optimized n = 4 RPP solar cells had PCEs of 13% with significant potential for further improvements.     

Investigations on the formation of composites by injection molding of PA6 and different grafted polypropylenes and their blends

Blends of different types of polypropylenes (PP) with polyamide 6 (PA6) were produced by extrusion. The PPs used were a PP homopolymer, a maleic anhydride‐grafted homopolymer, and an acrylic acid‐grafted homopolymer. The blends were characterized by DSC measurements, selective extraction, infrared spectroscopy, REM microscopy, melt rheology, and their mechanical properties. Three types of interactions in the blends as well as in two‐component composites mold by the core‐back process could be identified. Blends of PP with PA6 were not compatible, and two‐component bars could not be produced. Blends of PPgAA and PA6 were made compatible during reactive extrusion. Two‐component bars could be produced only with a blend containing 50 wt % PA6. The composite formation was based on the interdiffusion of PA6 in both components and the reactive compatibilization in the blends. Blends of PPgMAn were also compatibilized during reactive extrusion. The composite formation on two‐component injection molding was based on two mechanisms: the interdiffusion at sites, where PA6 chains of both the components came into contact, and an interfacial reaction, where PPgMAn and PA6 came into contact. The interfacial reaction was supported by the high mobility of the first component at the temperature of the melt of the second component. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 2992–2999, 2006     

Local repair procedure for carbon‐fiber‐reinforced plastics by refilling with a thermoset matrix

Textile‐reinforced composites have given rise to an increasingly important key technology for lightweight construction in aerospace, automotive, civil engineering, and many other industries. Because there exists no suitable repair procedure for carbon‐fiber‐reinforced plastics (CFRPs), damaged parts have to be replaced completely; this is extremely disadvantageous both ecologically and economically. With fiber‐reinforced composites used being more and more often, fast and efficient methods for the local repair of damaged CFRPs are essential. In this article, a novel repair procedure for CFRP is presented. The thermal activation by IR radiation of oxide semiconductors was used to locally degrade the thermoset matrix of the damaged CFRP through the maintenance of its structural stability and properties. The matrix‐free textile structure was then refilled with a thermoset epoxy matrix. Carbon fibers from the treated area were characterized with scanning electron microscopy, IR spectroscopy, thermogravimetric analysis, and subsequently, tensile strength for single fibers to verify the effectiveness of the procedure. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42964.     

Mannose‐Decorated Multicomponent Supramolecular Polymers Trigger Effective Uptake into Antigen‐Presenting Cells

A modular route to prepare functional self‐assembling dendritic peptide amphiphiles decorated with mannosides, to effectively target antigen‐presenting cells, such as macrophages, is reported. The monomeric building blocks were equipped with tetra(ethylene glycol)s (TEGs) or labeled with a Cy3 fluorescent probe. Experiments on the uptake of the multifunctional supramolecular particles into murine macrophages (Mφs) were monitored by confocal microscopy and fluorescence‐activated cell sorting. Mannose‐decorated supramolecular polymers trigger a significantly higher cellular uptake and distribution, relative to TEG carrying bare polymers. No cytotoxicity or negative impact on cytokine production of the treated Mφs was observed, which emphasized their biocompatibility. The modular nature of the multicomponent supramolecular polymer coassembly protocol is a promising platform to develop fully synthetic multifunctional vaccines, for example, in cancer immunotherapy.     

Dephosphorization equilibria between pure molten iron and CaO-saturated FeOn–CaO–CaF2 slags

Metal-slag refining reactions have been investigated to determine dephosphorization equilibria in steelmaking using CaO-saturated FeO_n–CaO–CaF₂ slags low in P₂O₅ content. Slag compositions have been optimized to achieve maximum partition ratios wt.%(P₂O₅)/wt.%[P] and minimum phosphorus contents in pure molten iron at 1 550 and 1 600°C. FeO_n–CaO–CaF₂ slags prove to be most effective dephosphorizers. Optimal slag compositions are between 10 and 20 wt.% FeO_n. Attempts were also made to present phosphate capacities fractions of free oxygen ions and theoretical optical basicities Λ as a function of the FeO_n content of slags. Dephosphorization capacity of FeO_n–CaO–CaF₂ slags is compared with that of FeO_n–CaO–SiO₂ and FeO_n–CaO–Al₂O₃ slags.