Demand for low-cost, environmentally friendly alternative renewable energy sources makes the dye-sensitized solar cell (DSSC) a viable alternative. DSSCs have a high but competitively challenged power conversion efficiency (PCE) of 11.9%. Plasmonic DSSCs is one approach with extreme enhancement of light absorption to increasing the PCE. The highest PCE of plasmonic DSSCs is still <11% however, due to secondary effects which are not yet well understood. In this study, we used a complex composite of plasmonic nanoparticles (PNPs) with extended characterization and wide ranging PNP loadings, combined with a systematic approach to obtain synergistic effects and a deeper understanding of the effects of plasmonic nanostructures on DSSC performance. The results showed two optimal loading amounts of PNPs with enhanced PCEs of 4.26 and 4.36% (from 3.54%), with enhancement effects obtained mainly from efficient charge injection and a balance of the negative and positive effects of the PNPs, respectively. An increase in the photoanode thickness from 5.5 to 9 µm resulted in PCE enhancement from 4.39 to 4.58%, mainly via efficient charge injection. The PNPs had both positive and negative effects on key DSSC performance parameters: decreased photoanode surface area but with panchromatic enhancement of light absorbance; increased short circuit current up to a point followed by a decrease due to poor charge injection; increased open circuit voltage and fill factor; enhanced charge transfer resistance against charge recombination; improved electron lifetime and charge collection efficiency; lowered enhancement of cell performance in the near infra-red region; and induced abundantly generated electrons augmented charge recombination. These results contribute significantly to understanding of the effects of plasmonic nanostructures and can serve as a useful guide to the study of plasmonic DSSCs and related fields.

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This report presents a new route to fabricating a ferrite-based magnetic nanocomposite consisting of a ferromagnetic metal (α-Fe) and a ferrimagnetic spinel ferrite (Fe₃O₄). The process is based on the eutectoid decomposition of FeO, leading to the formation of a lamellar nanostructure of α-Fe and Fe₃O₄. A sandwiched nanostructure of this type is preferable for exchange coupling between adjacent lamellae, because each lamella is subjected to exchange coupling via either side of the interface. It was found that decomposition of FeO takes place preferentially in the temperature range of 723–773 K, in which the decomposition is almost fully completed within 10 h. The room-temperature magnetization measurements gave rise to a high saturation magnetization above 100 emu/g, which is larger than that of single-phase Fe₃O₄. Since a smooth magnetization curve with single-phase-like behavior was observed despite the coexistence of two magnetic phases, the two phases could be magnetically exchange-coupled. Due to the ease of tuning the magnetic properties of the spinel ferrites with the substitution of constituent metal ions, the fabrication process described here could represent a potential route to making a variety of iron-based metal/ferrite magnetic nanocomposites.

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In this study, the densification, microstructures and elastic and mechanical properties of hot-pressed ZrB₂–20 vol % SiC composites with 3–10 wt % Cr₃C₂ additives were examined. The effects of the Cr₃C₂ content on the densification, microstructures and elastic and mechanical properties are discussed. The elastic moduli of the composites were calculated using measured longitudinal and transverse soundwave velocities, and the hardness and fracture toughness of the composites were determined using indentation measurements. The results show that the elastic moduli and fracture toughness are constant and independent of the Cr₃C₂ content, with a shear modulus of ∼200 GPa, Young’s modulus of ∼450 GPa and toughness of ∼4.7 MPa m^1/2. The hardness was measured as 18.2–20.9 GPa and was dependent on the Cr₃C₂ content. The flexural strengths of the composites were affected by the Cr₃C₂ content, with resulting strength values of 426–523 MPa.

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High crystallization, low-dielectric-loss Li₂O–xMgO–ZnO–B₂O₃–SiO₂ (x = 30, 35, 40, 45 and 50 wt.%) (LMZBS) glass–ceramics were prepared with different MgO contents using the solid-state method in this study. The effects of the MgO content on the microstructures, flexural strength and microwave dielectric properties of LMZBS were investigated. X-ray diffractometer results, for samples sintered at 920°C, for 30 wt.% ≤ x ≤ 35 wt.%, showed that the main phase was Mg₂B₂O₅ and the secondary phase was Li₂ZnSiO₄. But a new Mg₃B₂O₆ phase appeared when the MgO content exceeded 35 wt.%, becoming the main phase at x = 50 wt.%. Scanning electron microscopy showed that the average grain size decreased with increases in MgO and that a compact, homogeneous microstructure could be obtained at x = 40 wt.%. The Q×f value (product of qualify factor and resonant frequency) increased at first due to increases in the theoretical Q (quality factor) value and relative density, and then decreased due to a decrease in the average grain size and the appearance of large amounts of the liquid phase. Finally, the Li₂O–xMgO–ZnO–B₂O₃–SiO₂ glass-ceramics with 40 wt.% MgO exhibited excellent microwave properties and mechanical properties in terms of dielectric constants (ε_r = 6.66), Q×f = 54600 GHz, temperature coefficient of resonant frequency (τ_f = −35 ppm/°C) and flexural strength (σ = 160 MPa) after the samples were sintered at 920°C for 2 h in air, indicating their suitability as low-temperature co-fired ceramics.

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The crystallographic features of the ferroelectric tetragonal (FT) state in (1 − x)Pb(Sc_1/2Nb_1/2)O₃–xPbTiO₃ (PSN–xPT) were investigated between 300 and 700 K, primarily using transmission electron microscopy (TEM) with the help of the failure of Friedel’s law in electron diffraction. The ferroelectric state for 0.60 ≤ x < 1.0, which has been recognized as the normal FT state thus far, was found to have M_C-type monoclinic symmetry with ⟨201⟩_C polarization vectors in the {100}_C planes. Notably, the ferroelectric M_C state (FM_C) was characterized by pseudo 90 and 180° domain structures, in which the polarization rotates slightly from the ⟨001⟩_C direction of the FT state. In addition, in situ TEM observation during heating and permittivity measurement revealed that the (FM_C → FT) transition occurred at below T_C for 0.60 ≤ x < 1.0. The FT/FM_C phase boundary, which is nearly perpendicular to the temperature axis, was therefore present at approximately 560 K.

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Up-converting of GdTiNbO₆-based complex oxide co-doped with 5 mol % Er³⁺ and 10 mol % Yb³⁺ (GdTiNbO₆:Er³⁺/Yb³⁺) was conducted through a mild hydrothermal route. A single phase of aeschynite-type GdTiNbO₆:Er³⁺/Yb³⁺ was crystallized under weak basic hydrothermal conditions at 240°C for 5 h. The aeschynite-type structure was maintained after heating up to 1050°C for 1 h in air. A single phase of euxenite-type GdTiNbO₆:Er³⁺/Yb³⁺ was formed by heating at 1300°C for 1 h through phase transformation. The GdTiNbO₆:Er³⁺/Yb³⁺ emitted luminescence in the green spectral region from 515 to 560 nm (²H_11/2 and ⁴S_3/2 levels) under direct and indirect excitation of Er³⁺ at wavelengths of 377 and 277 nm, respectively, in addition to up-converted luminescence under excitation at 980 nm. The luminescence intensity was enhanced by high-temperature heating.

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We synthesized bulk CsBr samples in a transparent ceramic form by spark plasma sintering (SPS) and in a single crystal form by the vertical Bridgman-Stockbarger method, and investigated their optical, scintillation and dosimeter properties. In photoluminescence, scintillation, thermally-stimulated luminescence (TSL) and optically-stimulated luminescence (OSL), the CsBr in both the material forms showed broad emission peaks at around 450 nm, the origin of which was considered to be due to oxygen impurities. The TSL and OSL properties were notably enhanced in the transparent ceramic, in particular. The dosimetric sensitivities were confirmed to be as low as 0.01 mGy using TSL but were 1 mGy using OSL for both the transparent ceramic and single crystal forms.

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In order to estimate the upper limit of fly ash as an additive to fly ash cement, the dependence of the hydration reaction of fly ash cement on two parameters, i.e., the fly ash particle size and C₃S quantity, were evaluated based on theoretical simulation. In the early stage of the hydration reaction, the reaction ratio was largely independent of the fly ash particle size; however, the reaction ratio became remarkably dependent on the fly ash particle size during the stage from three weeks to one year. Because controlling the fly ash particle size is inexpedient in industry, only the quantity of fly ash required for fly ash cement to achieve properties similar to those of ordinary Portland cement was simulated by regulating the quantity of C₃S. It was found based on the simulations that fly ash cement containing 20% fly ash in high alite cement containing 67% C₃S was adequate, and this result was confirmed by empirical evaluation.

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The effect of adding cellulose nanofibers (CNFs), which are among the new materials attracting attention recently, to aqueous alumina (Al₂O₃) slurry was evaluated in order to investigate the possibility of using CNFs as a new forming aid. Al₂O₃ slurries with a small amount of CNFs (>0.1%) showed significant thixotropy. The slurry with 0.1% CNFs was cast in a gypsum mold, and Al₂O₃ green bodies with no cracks could be prepared after demolding and drying in air. Then Al₂O₃ sintered bodies with no cracks could be obtained after heating at 1600°C for 2 h. The densities of the green bodies and sintered bodies prepared from the slurry with CNFs were lower, however, than those prepared from the slurry without CNFs. In addition, the bending strength of sintered bodies prepared from the slurry with CNFs was also lower than that of those prepared from the slurry without CNFs. In order to prepare dense Al₂O₃ sintered bodies, it will be necessary to improve the density of the green bodies prepared from slurry with CNFs added.

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Dicalcium phosphate dihydrate (DCPD, CaHPO₄·2H₂O) has attracted attention as an environmental material recently because it reacts selectively with fluoride ions and transforms them into the highly stable, non-toxic material fluoroapatite [FAp, Ca₁₀(PO₄)₆F₂]. During this chemical reaction, the FAp particles retain their approximate shapes; in other words, DCPD particles act as templates for FAp particles. Our previous studies showed that the morphology of DCPD particles with tabular and petaloid shapes is controllable by use of a crystallization parameter under conditions of solution synthesis. DCPD has various applications, such as treatment of wastewater and polluted soil. Materials used for environmental purposes require not only appropriate chemical reactivity but also various powder properties to make them usable under various conditions. Thus, in this study, we compared the typical powder properties (bulk and tap densities, compressibility, Carr’s flowability index, sedimentation rate, and permeability) of the different morphologies of DCPD in terms of their suitability for environmental applications. The obtained results show that petaloid-shaped particles offer superior usability as compared to tabular-shaped particles.

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We have evaluated double-layer hydrogen electrodes with catalyst layers (CLs) and current-collecting layers (CCLs) in order to apply them in proton-conducting solid oxide cells. The scaffolds of the CLs were fabricated from a composite of mixed protonically-electronically conductive (MPEC) perovskite oxide BaCe_0.50Zr_0.27Y_0.20Ni_0.03O_3−δ (BCZYN) and Ni on a BaCe_0.10Zr_0.70Y_0.20O_3−δ electrolyte. Both powders were synthesized via a flame oxide-synthesis method and both had a unique microstructure, i.e., a fused-aggregate network structure [BCZYN(fans), Ni(fans)]. This unique structure was constructed from both a network of particles fused with their nearest neighbors and pores surrounded by the fused particles. This structure was found to be favorable for constructing both electronically conductive pathways and gas diffusion pathways in the CLs. Highly dispersed Ni nanoparticles [Ni(np)] were also loaded on the MPEC of BCZYN(fans) in the CLs. Composite CCLs of micrometer-sized BaCe_0.50Zr_0.30Y_0.20O_3−δ and Ni were also fabricated on the CLs. The catalytic activity of a hydrogen electrode using a CL comprising a composite of BCZYN(fans) and Ni(fans) was higher than that of a CL comprising BCZYN(fans) at a Ni(np) loading amount of 30 vol.% due to the improvement of the electronic conductivity in CLs by Ni(fans). The catalytic activity of the hydrogen electrode using the CLs increased with increases in the Ni(np) loading amount, moreover, and reached saturation at around 30 vol.% due to relief from the effect of the depletion layer on the outer surface of BCZYN(fans).

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Highly crystalline BaTiO₃ particles were hydrothermally synthesized at 250–400°C from the reactants of TiO₂ sol and Ba(OH)₂ solution. X-ray diffraction measurement patterns revealed that the crystal phase of the obtained particles was tetragonal, whereas tetragonality (c/a) was difficult to estimate due to the peak broadening of BaTiO₃ nanoparticles. The particle sizes determined based on the BET surface area and crystallite sizes were almost constant at 80 and 40 nm, irrespective of the hydrothermal temperature. Based on TG–DTA analyses, the lattice OH content decreased with increases in the hydrothermal temperature. In-situ Raman spectra were conducted in the temperature range from 25 to 200°C to follow the tetragonal-to-cubic transformation. The tetragonal-to-cubic phase transition was clearly observed at 120–130°C for the BaTiO₃ hydrothermally synthesized at 400°C, whereas the BaTiO₃ hydrothermally synthesized at 250–350°C exhibited a delayed transition at above 150°C due to peudo-cubic behavior. The tetragonality of BaTiO₃ synthesized at 400°C can be assumed to be prominent owing to the lower number of lattice OH groups.

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