Nd3+‐Doped Silicate Glasses as an Efficient Color Filter to Improve the Color Gamut of a White LED

Nd³⁺‐doped silicate glass (Nd‐glass) was employed as a color filter for a white LED based on red and green phosphor (RG‐LED), to manipulate the photoluminescence spectral shape and thus to provide a wider color gamut. The hypersensitive transition of Nd³⁺:⁴I_9/2→⁴G_5/2,²G_7/2 was adjusted via glass composition and Nd concentration, and improved absorbance as well as reduced the absorption bandwidth. The effective absorption of the Nd‐glass at ~580 nm reduced the spectral linewidth of the green and red emissions, improving the color reproduction range. The color gamut of the RG‐LED was improved from 75.3% to 81.6% NTSC by the introduction of Nd‐glass as a color filter. Reliability under high operating current and high temperature were also examined and discussed.     

A 3‐Fluoro‐4‐hexylthiophene‐Based Wide Bandgap Donor Polymer for 10.9% Efficiency Eco‐Friendly Nonfullerene Organic Solar Cells

Nonfullerene organic solar cells (NFOSCs) are attracting increasing academic and industrial interest due to their potential uses for flexible and lightweight products using low‐cost roll‐to‐roll technology. In this work, two wide bandgap (WBG) polymers, namely P(fTh‐BDT)‐C6 and P(fTh‐2DBDT)‐C6, are designed and synthesized using benzodithiophene (BDT) derivatives. Good oxidation stability and high solubility are achieved by simultaneously introducing fluorine and alkyl chains to a single thiophene (Th) unit. Solid P(fTh‐2DBDT)‐C6 films present WBG optical absorption, suitable frontier orbital levels, and strong π–π stacking effects. In addition, P(fTh‐2DBDT)‐C6 exhibits good solubility in both halogenated and nonhalogenated solvents, suggesting its suitability as donor polymer for NFOSCs. The P(fTh‐2DBDT)‐C6:3,9‐bis(2‐methylene‐(3‐(1,1‐dicyanomethylene)‐indanone))‐5,5,11,11‐tetrakis(5‐hexylthienyl)‐dithieno[2,3‐d:2′,3′‐d′]‐s‐indaceno[1,2‐b:5,6‐b′]dithiophene (ITIC‐Th) based device processed using chlorobenzene/1,8‐diiodooctane (CB/DIO) exhibits a remarkably high power conversion efficiency (PCE) of 11.1%. Moreover, P(fTh‐2DBDT)‐C6:ITIC‐Th reaches a high PCE of 10.9% when processed using eco‐friendly solvents, such as o‐xylene/diphenyl ether (DPE). The cell processed using CB/DIO maintains 100% efficiency after 1272 h, while that processed using o‐xylene/DPE presents a 101% increase in efficiency after 768 h and excellent long‐term stability. The results of this study demonstrate that simultaneous fluorination and alkylation are effective methods for designing donor polymers appropriate for high‐performance NFOSCs.     

Enhanced mechanical response of magnesium alloy ZK60A containing Si3N4 nanoparticles

ZK60A Nanocomposite containing Si₃N₄ nanoparticles was fabricated using solidification processing followed by hot extrusion. The ZK60A nanocomposite exhibited smaller grain size than monolithic ZK60A, significantly reduced presence of intermetallic phase, reasonable Si₃N₄ nanoparticle distribution, non-dominant (0 0 0 2) texture in the longitudinal direction, and 12% lower hardness than monolithic ZK60A. Compared to monolithic ZK60A (in tension), the ZK60A nanocomposite simultaneously exhibited higher 0.2% TYS, UTS, failure strain and work of fracture (WOF) (+21%, +17%, +85% and +119%, respectively). Also, compared to monolithic ZK60A (in compression), the ZK60A nanocomposite exhibited lower 0.2% CYS (−33%) and higher UCS, failure strain and WOF (+16%, +53% and +48%, respectively). The effect of adding Si₃N₄ nanoparticles on the enhanced tensile and compressive response of ZK60A is investigated in this paper.     

Wrapping Graphene Sheets Around Organic Wires for Making Memory Devices

Hybrids of organic semiconductors and graphene can generate a whole new class of materials with enhanced properties. A simple solution‐phase route to synthesize a hybrid material made of organic nanowires and graphene oxide (GO) sheets is demonstrated by sonicating tetracene molecules and GO together in diluted fuming nitric acid. The self‐assembled tetracene‐derived organic wires become encapsulated by GO sheets during the reaction to produce an interconnected, one‐dimensional/two‐dimensional lamellar film. Memory devices fabricated using the hybrid film as the sandwiched layer between aluminum electrodes exhibit excellent electrical bistability. The charge retention properties are attributed to charge transfer and a charge‐trapping/detrapping mechanism operational at the interfaces and isolated matrices of the GO–tetracene hybrid.     

Three-dimensional photonic crystal fluorinated tin oxide (FTO) electrodes: synthesis and optical and electrical properties

Photovoltaic (PV) schemes often encounter a pair of fundamentally opposing requirements on the thickness of semiconductor layer: a thicker PV semiconductor layer provides enhanced optical density, but inevitably increases the charge transport path length. An effective approach to solve this dilemma is to enhance the interface area between the terminal electrode, i.e., transparent conducting oxide (TCO) and the semiconductor layer. As such, we report a facile, template-assisted, and solution chemistry-based synthesis of 3-dimensional inverse opal fluorinated tin oxide (IO-FTO) electrodes. Synergistically, the photonic crystal structure possessed in the IO-FTO exhibits strong light trapping capability. Furthermore, the electrical properties of the IO-FTO electrodes are studied by Hall effect and sheet resistance measurement. Using atomic layer deposition method, an ultrathin TiO(2) layer is coated on all surfaces of the IO-FTO electrodes. Cyclic voltammetry study indicates that the resulting TiO(2)-coated IO-FTO shows excellent potentials as electrodes for electrolyte-based photoelectrochemical solar cells.     

Characterisation of duplex stainless steel subjected to long-term annealing in the sigma phase formation temperature range by the DLEPR test

The effects of long-term thermal annealing (15,000 h) between 630 and 800 °C on the duplex stainless steel (DSS) 7MoPLUS are investigated by using the double loop electrochemical potentiodynamic reactivation (DLEPR) test. The morphology of the sigma phase exerts a bigger influence on the corrosion resistance than does its composition. No healing has been observed in present DSS, although it has been found in the lean DSS 2101 by other researchers. The healing mechanism in the sigma-phase formation range has been discussed and the reason for the absence of healing in the present steel has been suggested.     

Rational design of fluorescent biosensor for cyclic di-GMP

Messenger bagged: The design of a fluorophore-labeled protein biosensor for the bacterial messenger cyclic di-GMP is described. The biosensor responds to c-di-GMP with sub-micromolar sensitivity in a real-time fashion. The biosensor can be used for enzyme assays for diguanylate cyclases and c-di-GMP phosphodiesterases as well as the high-throughput screening of inhibitors.     

Characteristics of the Skin Layers of Microcellular Injection Molded Parts

The cross-section of products made with the microcellular injection molding process shows the skin layer and the core region where the formation of pores takes place. The cell size, cell density, and cell morphology were found to depend on pressure drop rate, viscosity, cell growth period, and cell coalescence. However, research on the actual mechanisms of the skin layer is rare.

Cell morphology and skin layer are of importance as a factor influencing the density and strength of microcellular injection molded parts. Especially, as size of the injection molded parts becomes large, the skin layer size changes, resulting in variation of the foaming rate. Therefore, there is the need to study factors that influence the formation of the skin layer and its thickness.

This research proposes a hypothesis on the mechanism of the skin layer formation in microcellular injection molding process and addresses factors influencing skin layer thickness. In addition, the experimental design method was utilized to identify the factors, and the variation in physical properties with skin layer thickness was reported.