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This study explores a novel reactive cold sintering method for improving the density of gadolinia‐doped ceria (GDC) ceramics while reducing the annealing temperature. Instead of using deionized water as an aid in conventional cold sintering, stoichiometrically mixed Ce(NO3)3·6H2O and Gd(NO3)3·6H2O precursors were added as additives during the CSP in this study. The effects of processing parameters such as sintering temperature and additive content on the relative density of the compacts were investigated using synthesized GDC and commercial GDC powders as raw materials. The results showed that with the aid of precursors, GDC ceramics were sintered up to 90% of their theoretical densities at 850°C and up to 94% at 950°C when the synthesized nanopowder GDC was used. Additionally, the sintering mechanism was investigated, and it was found that the GDC generated by the precursor reaction effectively filled the gaps between the original particles, promoting densification of the sample after cold‐pressing. [ABSTRACT FROM AUTHOR]

Quantum dots–embedded glasses (QDEGs) can combine the unique optical properties of QDs with high physicochemical stability and good mechanical properties of glasses, which have been widely investigated and applied in lighting and display. However, precise controlling the concentration and size distribution of QDs, and precipitating QDs with desired compositions or multicomponents in glass are still challenges for the traditional melt‐quenching method. Herein, a series of alloyed Cd–Zn–S QDEGs from green to red emission is successfully prepared via a novel fabrication strategy for the first time. Specifically, the solid‐solution precursors crack during the sintering process to form the well‐dispersed QDs with a narrow distribution, attributing to the gradient sulfur composition and the shearing force induced by the thermal migration of sulfur vacancies. Significantly, the quantum yield of Cd0.5Zn0.5S QDEG could reach 30%, among the top results of efficient red‐emissive QDEG materials. Finally, using QDEGs as light converters, a UV‐pumped warm white light–emitting diode with a correlated color temperature of 4238 K was achieved, which demonstrate the potential applications of the alloyed Cd–Zn–S QDEGs. These results will inspire more explorations on this fabrication strategy to develop novel QDEGs with a high optical performance for practical applications. [ABSTRACT FROM AUTHOR]

Mn2+ activated glass‐ceramic (GC) has received tremendous attention in the exploration of luminescent materials for solid‐state lighting due to the high stability, broad red emission, and low toxicity. However, the doped Mn2+ ions still suffer from the oxidation and uncontrollable ions migration during the melting process of conventional preparation techniques, which is detrimental to the luminescence performance. Herein, transparent Mn2+‐doped mullite GCs have been prepared at low temperature (∼850°C) via the spark plasma sintering of EMT‐type zeolite. The GC samples show typical red emission peaking at 620 nm that can be assigned to spin‐forbidden 4T1(G)→6A1(S) transition of Mn2+ located in the octahedral coordination site of the host. Owing to the charge compensation mechanism and produced oxygen vacancies, the self‐reduction of Mn3+ to Mn2+ ions is realized and the oxidization is inhibited. The mullite nanocrystals acted as additional scattering centers introduce Rayleigh scattering to enhance the emission intensity. Moreover, benefitted from the established mullite nanocrystals network, the Mn2+‐doped GCs exhibit improved thermal conductivity up to 1.79 W K−1 m−1 and more excellent mechanical properties than conventional GCs, simultaneously. [ABSTRACT FROM AUTHOR]

Phosphors‐in‐glass (PiG), which serves as a potential bi‐replacement of both phosphors and organic encapsulants in high‐power white light‐emitting diodes (WLEDs), has captured much attention due to its high thermal stability and excellent luminescent properties. However, due to the high‐temperature sensitivity and the chemical reactions between phosphors with glass matrix, a variety of phosphors, especially red phosphors could be hardly dispersed into the glass without thermal quenching and decomposition, which greatly limits the improvement of color rendering index and chromaticity tunability of the WLEDs. In this study, adopting the mesoporous silica (FDU‐12) and commercial phosphors as raw materials, the phosphors‐in‐silica‐glasses (PiSGs) embedded with red phosphor CaAlSiN3:Eu2+ and yellow phosphor YAG:Ce3+ have been successfully prepared at low sintering temperature (950°C) and short preparation time (10 minutes) using spark plasma sintering. Owing to the well preservation of the originally emissive properties of the embedded phosphors, the warm WLEDs with tunable chromaticity and exhibited a superior performance with LE of 133 lm/W, CCT of 3970 K and CRI of 81 were fabricated by encapsulating the as‐prepared PiSGs on the blue chips. Moreover, the PiSG composite exhibits a high thermal conductivity up to 1.6 W/m·K. [ABSTRACT FROM AUTHOR]

Monolithic luminescent glass‐ceramic (GC) embedded with fluoride‐based nanocrystals (NCs) has drawn much attention as it is stable and possesses long fluorescent lifetime, while only small partial of optically active ions could enter the fluoride NCs prepared by conventional crystallization process. In this work, YF3:Eu3+ embedded GCs have been controllably synthesized by Spark Plasma Sintering at a relatively low sintering temperature (960°C) within 10 minutes. The GC samples show typical sharp reddish‐orange emissions peaking at λ = 590 nm and 620 nm, which can be ascribed to the 5D0 → 7Fj transitions of Eu3+ located in the tetrahedral coordination sites of the YF3 NCs. Significantly, a small R/O ratio (photoluminescence intensity ratio of 5D0 → 7F2/5D0 → 7F1) suggests that majority of Eu3+ ions are well preserved in YF3 NCs, which is confirmed by the EDS and TEM results that highly crystallized YF3:Eu3+ NCs are homogeneously dispersed into the silica glass matrix without interfacial reaction. Hence, the lifetime of GC sample is prolonged to 6.8 ms These results demonstrate that Eu3+ could be well protected and resided in YF3 low phonon crystal by this method to fabricate GC composites with high optical performance. [ABSTRACT FROM AUTHOR]

In this paper, the Nd3+-doped mesoporous molecular sieves (FDU-12) nanocomposites were synthesized by hydrothermal method with the triblock copolymer (F127) as the template and the ethylorthosilicate (TEOS) (AlCl3) as modifier. Nd3 was rapidly doped into FDU-12 mesoporous molecular sieves during the synthesis. The synthesized samples were characterized by X-ray powder diffraction (XRD), isothermal adsorption-desorption, transmission electron microscopy (TEM) and fluorescence spectroscopy. The results show that the element Nd is present in the FDU-12 mesoporous molecular sieve in the +3 valence state. The synthesized FDU-12/Nd molecular sieve has a regular face-centered cubic pore structure. When the sample is subjected to fluorescence test with the LED laser 808 nm, the characteristic emission peaks of neodymium ions at 912, 1 065 and 1 350 nm indicate that FDU-12/Nd mesoporous molecular sieves exhibit good fluorescence performance and are favorable for achieving high efficiency laser output. FDU-12/Nd mesoporous molecular sieves can be a new type of Nd-doped laser or amplifier materials and have broad application prospects. [ABSTRACT FROM AUTHOR]

Prussian blue (PB) and its analogues (PBAs) have been acknowledged as promising materials for the catalysis, energy storage, and bioapplications because of different constructions and tunable composition. The approach for surface modification with metal oxides for boosting the performance, however, is rarely reported. Herein, a facile surface anchoring strategy has been proposed to realize CeO 2 nanocrystals uniformly depositing on the surface of PB. Besides, the size, thickness, and depositing density of CeO 2 nanocrystals can be regulated by adjusting the amount of the precursor and the proportion of ethanol and deionized water. Furthermore, after a step of confined pyrolysis treatment under an air atmosphere, CeO 2 nanocrystals with an encapsulated iron oxide structure have been obtained. This shows a remarkable cycling and rate performance when evaluated as an anode of the lithium-ion battery. The surface anchoring approach of the CeO 2 nanocrystals may not only promote the various applications of PB-based materials but also provide an opportunity for developing the architecture of other CeO 2 -based core-shell nanostructures.

Semiconducting metal oxides with abundant active sites are regarded as promising candidates for environmental monitoring and breath analysis because of their excellent gas sensing performance and stability. Herein, mesoporous WO 3 nanofibers with a crystalline framework and uniform pore size is successfully synthesized in an aqueous phase using an electrospinning method, with ammonium metatungstate as the tungsten sources, and SiO 2 nanoparticles and polyvinylpyrrolidone as the sacrificial templates. The obtained mesoporous WO 3 nanofibers exhibit a controllable pore size of 26.3-42.2 nm, specific surface area of 24.1-34.4 m 2 g -1 , and a pore volume of 0.15-0.24 cm 3 g -1 . This unique hierarchical structure, with uniform mesopores and interconnected channels, could facilitate the diffusion and transportation of gas molecules in the framework. Gas sensors, based on mesoporous WO 3 nanofibers, exhibit an excellent performance in acetone sensing with a low limit of detection (<1 ppm), short response-recovery time (24 s/27 s), a linear relationship in a broad range, and good selectivity.