Duo to the unique luminescent property, thermal conductivity and chemical stability, phosphors/glass composite (Phosphor-in-Glass, PiG) has a huge market application prospect as an alternative to silicon-based phosphor converter for conventional white LEDs, as well as a solution to the heat emission, luminous efficiency, quality, glare, lifetime and other technical problems at the same time. Herein, some key scientific topics in terms of PiG materials were analyzed, such as luminescence properties, transparency, mechanical strength, and mass production; the targeted optimization measures were also comprehensively summarized, including preparation methods (tabletting sintering, melt quenching, and film sintering), material composition design, and the structure optimization of phosphor layers. Generally, this review presents the most recent advances of excellent performance PiG materials, and also prospects their research trend.

Gadolinium iodide doped with Cerium (GdI₃:2%Ce) and undoped gadolinium iodide (GdI₃) crystals were grown by vertical Bridgman method with sealed quartz crucible. Crystal ingots with dimension of ϕ15 mm×20 mm were cut and polished to be plates of 12 mm×10 mm×2.5 mm and 11 mm×8 mm×2.5 mm. GdI₃:2%Ce without crack and inclusion were encapsulated for all the measurements. X-ray diffraction analysis shows that the Ce³⁺-doped GdI₃ and undoped GdI₃ crystal have the same structure. X-ray and ultraviolet excited luminescence spectra of GdI₃:2%Ce present broad emission bands peaking at 520 nm and 550 nm, respectively, which correspond to 5d-4f transition luminescence of Ce³⁺. Three peaks located at 262, 335 and 440 nm can be observed in excitation spectra when photoluminescence is monitored at 550 nm. The GdI₃:2%Ce crystal presents an excellent energy resolution of 3.4% and decay time of (58±3) ns under excitation of 662 keV gamma-rays from ¹³⁷Cs source. The results show the GdI₃:2%Ce crystal is a promising scintillator for gamma ray and neutron detection.

SiC nanoparticles were synthesized by direct current (DC) arc-discharge plasma method, using bulk Si as silicon source and in a mixed atmosphere of CH₄, H₂ and Ar. The chemical composition and morphology of the SiC nano product were affected by the pressure of CH₄ obviusly. These products were characterized by Transmission electron microscopy (TEM), Raman spectra, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results indicate that the product contains the main phases of 3C- and 6H-SiC, while prepared at low CH₄ pressure of 0.005 MPa, which exists few Si/SiC core-shell structures in the product. The SiC nanoparticles, prepared at 0.01 MPa CH₄, were used as the catalyst to remove the Cl atoms in persistent 2,4-dichlorophenol through photoelectric catalytic reduction. The results show that the SiC nanoparticles have good photoelectric catalytic reductive dechlorination ability under ultraviolet illumination at a constant optical intensity of 500 mW/cm². The removal efficiency reaches about 92.5% and the adsorption efficiency is 19.6% at an appropriate bias potential of -1.02 V after 180 min of photoelectric catalysis. Hence, SiC nanoparticles are identified as a kind of low-cost photoelectrocatalysis candidates to replace noble metals in wastewater treatments.

A series of mesoporous graphene oxide/TiO₂ composites (GO/TiO₂) with different mass fractions of graphene oxide (GO) were synthesized by an in-situ synthesized Sol-Gel step using GO, tetrabutyl titanate (TBT) as precursors, polyvinylpyrrolidone (PVP) as frame developing agent and citric acid as hydrolysis inhibitor and surfactant. Afterwards, mesoporous reduced graphene oxide/TiO₂ (RGO/TiO₂) composites were obtained by ultraviolet radiation reduction method. The composites were characterized by X-ray diffraction (XRD), Transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), UV-visible diffuse reflectance spectroscope (UV-Vis DRS), and photoluminescence (PL) spectroscopy technology. The morphology and pore size distribution of RGO/TiO₂ and the effects of RGO on the lifetime of photogenerated electron-hole pairs, adsorption capacity and photocatalytic activity of composite photocatalysts were investigated. The photocatalytic activity was evaluated under ultraviolet light and sunlight irradiation. Then the recovery test was studied under ultraviolet light irradiation. Results show that TiO₂ nanoparticles are well dispersed on the surface of the RGO sheets and RGO/TiO₂ composites are mesoporous materials. The introduction of RGO effectively inhibits the recombination of photogenerated electron-hole pairs and improves the adsorption capacity and photocatalytic activity of composites. The 7wt% RGO/TiO₂ shows the best adsorption capacity for methyl orange. And 5wt% RGO/TiO₂ shows the best and stable photocatalytic activity, after four recovery test, its photocatalytic degradation of methyl orange under ultraviolet light irradiation for 50 min exceeded 90% of the first test.

By using titanyl sulfate and ammonia metatungstate (AMT) as precursors and citric acid as a complexing agent, mesoporous hollow spheres of TiO₂/WO₃ composites were prepared via a two-step approach, which included a spray-drying process followed by a high-temperature calcination course. The morphologies, microstructures, surface area, crystal phase, and optical properties of the composites were characterized by SEM, TEM, BET, XRD and UV-Vis DRS. The results showed that the TiO₂/WO₃ composites were well-dispersed mesoporous hollow spheres with diameters around 1 μm, of which the wall consisted of nanoparticles and mesopores. What’s more, nanoparticles and mesopores increased with the calcination temperature. UV-Vis DRS analysis showed that the absorption spectra of TiO₂/WO₃ composites could extend from ultraviolet region to visible region, which was helpful to improve the utilization efficiency of sunlight. In addition, photocatalytic activities of the prepared samples were investigated by photo-degradation of methylene blue (MB). It’s found that the composite containing 3% molar ratio of WO₃ with calcination temperature of 500^oC showed the best photocatalytic activity. The degradation efficiency of MB with this composite could reach 99.1%, much higher than that of P25, which was only 29.5% under the same conditions.

Zn-Ni hydroxide nano-sheets were successfully deposited on nickel foams through a mild, cost-effective chemical bath method. SEM observation shows that these interconnected nano-sheets form a uniform marray layer and completely cover the surface of nickel foam. At the same time, additional homogeneously-precipitated hydroxide nano-sheets locate in the skeleton voids of nickel foams as aggregated porous clumps, resulting in a relatively high mass-loading of 4.27 mg/cm². Afterwards, the electrochemical capacitive behaviors of this binder-free electrode were investigated by cyclic voltammetry, galvanostatic charge/discharge tests and electrochemical impedance spectroscopy. It is found that the Zn-Ni hydroxide electrode exhibits a specific capacitance of 746.2 F/g (areal capacitance of 3.18 F/cm²) at a current density of 1 A/g in 2 mol/L KOH electrolyte. Meanwhile, the Zn-Ni hydroxide electrode also shows a decent long-life cycling stability, retaining 70.9% of the initial capacitance after 3000 charge-discharge cycles.

The solid oxide fuel cell nanometer composite cathodes were prepared by infiltration of La_0.6Sr_0.4Co_0.8Fe_0.2O_3-δ(LSCF) precursor solution into porous Ce_0.8Sm_0.2O_1.9(SDC) scaffolds followed by being calcined at 800℃for 4 h. The composition and the microstructure of the cathodes were analysed by X-ray diffraction (XRD) and scanning electron microscope (SEM). Average particle size of the LSCF phase is about 50 nm after being calcined at 800℃ for 4 h. The reduction reaction mechanism of O₂ in the LSCF/SDC cathodes and the influence of LSCF loadings on the cathode properties were studied in terms of frequency response, electrode resistance and reaction order at different oxygen partial pressures p(O₂). Three elementary steps are considered to be involved in the cathodes reaction: (1) absorption and dissociation of molecular O₂; (2) oxygen ion conduction in the bulk cathode; (3) oxygen ion transfer at the cathode-electrolyte interface. The oxygen ion conduction in the bulk cathode is found to be the rate-determining steps in the nano-sized LSCF-SDC composite cathode. The reduction reaction mechanism of O₂ in the cathodes is similar to the samples with different LSCF loadings. The polar resistance of the cathode firstly decreases and then increases with increasing the LSCF loadings. The cathode polar resistance reaches the lowest when the volume fraction of LSCF loadings is 16.5vol%.

A 3D composite electrode was prepared by ultrasonic dispersion of a suspension mixed proportionally with 4A molecular sieve (4A) and graphene oxide gel (GO). The structure, morphology and electrochemical property of the 4A/reduced graphene oxide (RGO) composite were investigated by X-ray diffraction, Raman spectra, pore analysis, scanning electron microscope (SEM) and electrochemical measurements. The result shows that 4A is firmly adhered on the surface of RGO sheets, which can effectively avoid the stacking of RGO sheets. The RGO sheets link with each other to form a 3D electric conductive network in which can increase the electrical conductivity of the composite. The specific capacitance of 4A/RGO composite can reach 450 F/g at current density of 4 A/g when the mass ratio of graphene oxide and 4A is 1:6. Furthermore, the specific capacitance of 4A/RGO remains at 85.7% after 800 cycles under the same current density. Therefore these results indicate that this new composite possesses good rate capability and cycle stability and its supercapacitive performance is better than that of pure RGO or 4A. The excellent performance of the 4A/RGO composite can be attributed to the synergy between RGO and 4A.

Cathode catalyst is a dominant parameter hindering the development of proton exchange membrane fuel cells (PEMFCs), exploiting non-precious metal based catalysts with low cost and high activity has become an urgent task in recent decades. In this work, a non-precious metal based catalyst of heat-treated nitrogen doped carbon supported transition metal based catalyst (M-N/C catalyst) was chosen as the subject, and a series of Fe-PPy-TsOH/C catalysts were synthesized with iron salt as the metal precursor, BP 2000 carbon black as the carbon source, polypyrrole (PPy) as the nitrogen source, and methyl benzene sulfonic acid (TsOH) as the dopant. The effects of heat-treatment temperature and cobalt-doping on the phase structure, morphologyand catalytic performance towards oxygen reduction reaction (ORR) were comparatively investigated. It shows that 800℃ is the optimal heat-treatment temperature to prepare high performance Fe-PPy-TsOH/C catalyst. If the iron in the Fe-PPy-TsOH/C catalyst is replaced by appropriate amount of cobalt, its catalytic performance towards ORR could be further improved, and the best ORR performance could be achieved at a cobalt cotent of 33.33% (Fe:Co=2:1 in ratio) in the range of 0-50at%.

In order to reduce the thermal stress of solid oxide fuel cell in the process of preparation and working, and improve the electrochemical performance of the cell, the functionally graded layer is introduced into the cell. Due to the property of the functionally gradient material changes continuously or stepwise in a certain direction, the layer can reduce the difference of material parameters and relieve the thermal mismatch stress between layers effectively. On the basis of the previous research and the idea of hierarchical method, the anode functional layer is introduced into the solid oxide fuel cell, and the material parameters of the sub-layers are controlled through the anode functional layer number and the nonlinear gradient component exponent n. Thermal stress of the solid oxide fuel cell is studied at 800℃ within the operating temperature. The results show that the maximum tensile stress of the anode layer and the maximum compressive stress of the electrolyte layer decreases by introducing the anode functional layer. With the same anode functional layer number, the maximum tensile stress increases with the exponent n, and the maximum compressive stress of the electrolyte layer decreases with the exponent n increase. The thermal stress may lead to cracks and destroy the solid oxide fuel cell structure. This research provides theoretical basis for design and optimization of the solid oxide fuel cell.

Vanadium boride compound powders with different compositions were prepared by reactive synthesis at 1500℃ from elemental powders. Then, with the obtained powders as active materials, Ni powder as conductive agent and NH₄HCO₃ as space-holder, the porous anodes of V-xB/Ni (x=2/3~2) were fabricated by powder metallurgy (PM), respectively. The effects of V-xB compounds with different phases on the discharge performance of the assembled air batteries were studied. The results show that the single-phased VB₂ powder can be obtained from the raw powder with the atomic ratio of V:B=1:2, and so does the VB powder. As for atomic ratio of V:B=3:2, the synthesized powder consists of V₃B₂ and a small amount of VB, while the ratio of V:B=2:3 yields the phase composition of V₂B₃, V₃B₄ and minor VB₂. The prepared V-xB/Ni anodes with porosity of 60.25%-61.75% exhibit good discharge performance, and their capacity can reach the range of 6129-7901 mAh while specific capacity is 2724-3511 mAh/g. With the increase of B content, the discharge performance of V-xB/Ni anodes shows a significant improvement. In comparison, the porous V-2B/Ni anode possesses the superior discharge properties with discharge capacity of 3512 mAh/g, coulombic efficiency of 86.5% and specific energy of 2504 Wh/kg.

CdS:Al thin films with different doping concentrations were deposited by controlling deposition rate of CdS and Al targets in co-sputtering process. The morphological, structural, optical, and electrical properties of as-prepared CdS:Al films were investigated by X-ray diffraction (XRD), atomic force microscope (AFM), UV-visible absorption spectrum, and room temperature Hall-system. XRD patterns indicates that all the CdS:Al films are polycrystalline films with hexagonal wurtzite structure and have a preferential orientation in (002) direction. The uniform and compact films can effectively be formed on insulating substrates. It is worth noting that the average grain size increases with Al doping concentration. On the other hand, the surface root-mean-square (RMS) roughness also shows slightly increase. UV-visible transmittance spectra show that the band gap of CdS:Al film decreases slightly in the range of 2.42-2.46 eV with increasing Al doping concentration. The Hall measurements indicate that the effect of Al doping concentration on electrical property of CdS films is apparent. In comparison with the un-doped CdS thin films, the carrier concentration of CdS:Al films increases by three orders of magnitude when the Al concentration is higher than 3.8%, while the resistivity of which decreases by three orders of magnitude. The doping level of CdS films is improved by doping with Al atoms to enhance the built-in electric field, which may realize high open voltage (V_oc) for CdTe thin film solar cells. The properties of CdS:Al film prepared by co-sputtering are suitable as a window layer of CdTe thin film solar cells.

The ceramic coatings were prepared by micro-arc oxidation (MAO) on the TiC_P/Ti6Al4V composites. The effects of NaOH, C₁₀H₁₂CaNa₂N₂O₈·4H₂O and Na₂SiO₃ additives in NaAlO₂ and NaH₂PO₂ solutions on the microstructure, corrosion resistance and wear resistance of the ceramic coatings were investigated, respectively. The results showed that coatings prepared in NaH₂PO₂ solution were composed of rutile and anatase TiO₂, while coatings prepared in NaAlO₂ solution consisted of Al₂TiO₅, γ-Al₂O₃, rutile and anatase TiO₂. The NaOH addition could increase reaction rate of the micro-arc oxidtion, and the hardness of the MAO coatings could be enhanced by the addition of NaAlO₂ and Na₂SiO₃. The thickness of the coatings formed in NaH₂PO₂ solution is 2-3 times thicker than that of the coating formed in NaAlO₂ solution. The corrosion resistance of the coatings formed both in NaAlO₂ and NaH₂PO₂ solutions, ranked from additives: Na₂SiO₃>C₁₀H₁₂CaNa₂N₂O₈·4H₂O>NaOH. Wear resistance of the coatings formed in the NaAlO₂ solution ranked from the additives: Na₂SiO₃>NaOH>C₁₀H₁₂CaNa₂N₂O₈·4H₂O, while the wear resistance formed by NaH₂PO₂ solution ranked from additives: Na₂SiO₃>C₁₀H₁₂CaNa₂N₂O₈·4H₂O>NaOH. After micro-arc oxidation, all of the corrosion resistant and wear resistance of the MAO coatings were higher than those of the untreated TiC_P /Ti6Al4Vcomposites. The mciro-arc oxidation coatings formed in NaH₂PO₂+Na₂SiO₃ solution showed the best corrosion resistance (about two orders of magnitude higher than that of the substrate) and better wear resistance.

Since the macro anti-penetration performance of interpenetrating SiC/Al composite is controlled mainly by the complex three-dimensional microstructure features. Muti-scale simulation of SiC/Al composite under impact loading was performed by using a macro-micro method. The simulation for macro SiC/Al composite armor plate under impact loading was employed first, then the dynamic boundary conditions from the typical local regions in SiC/Al composite were obtained and applied on its microstructural finite element model as a loading condition to analyze the dynamic damage and failure process in the typical local regions. The results revealed that, in the local region right below the impact point, the cracks initiated mainly near the SiC/Al interface, just on the side of the SiC ceramic phase, then continuously propagated parallel to the direction of the bullet axis and eventually converged together to form axial main cracks. Meanwhile, in the region at a 45º angle to the direction of bullet axis, the cracks initiated not only near the SiC/Al interface but also inside the ceramic phase. Subsequently, these cracks propagated, bridged and finally formed cone main cracks. This simulation method provides a feasible technical approach for microstructure topology optimization of the material.

Aluminum phosphate coatings containing different levels of Cu²⁺ ions (Cu/Al molar ratio: 0.025, 0.05, 0.1) were prepared on 316-stainless steel based on the curing reaction of monoaluminium phosphate (MAP). The curing behaviors of the starting materials and phase compositions of the cured products were studied by differential scanning calorimetry and X-ray diffraction, respectively. Results indicate that the copper-free MAP cures at ≤250℃ to form 3 major phases: AlH₂P₃O₁₀·2H₂O, AlPO₄, and Al₈H₁₂(P₂O₇)₉. When Cu²⁺ ions are introduced into the MAP, an additional phase of Cu₂P₂O₇ appears in the cured product. E. coli was inoculated on the surfaces of coatings to evaluate their antibacterial properties. After co-culture with E. Coli for 12 h, all Cu²⁺-containing coatings exhibit antibacterial effect and show a positive association between Cu²⁺ content and antibacterial activity. After co-culture for 24 h, no viable bacteria remain on any Cu²⁺-containing coating. The addition of ethylenediaminetetraacetic acid to the culture medium substantially inhibits the antibacterial activities of all coatings, confirming that the antibacterial effect is attributed to the release of Cu²⁺ ions from coatings. Pull-out tests show that the bonding strengths of the coatings range between 14.5-18.1 MPa. Potentiodyanmic polarization indicates that the coatings reduce the corrosion current density of the stainless steel substrate by approximately two orders of magnitude.

High quality stoichiometric VO₂ films were grown on single crystal sapphire substrates by molecular beam epitaxy (MBE), the film thicknesses were precisely controlled on the nanoscale ranging from 15 nm to 60 nm. For the optimized sample, a distinct reversible metal-insulator transition (MIT) with abrupt resistance change more than four orders of magnitude was observed, which was comparable to the ever reported result for high quality single crystal VO₂. Especially, the optical properties in the terahertz (THz) frequency range were characterized with THz time-domain spectroscopy (THz-TDs) measurements for samples with various thicknesses, and the results indicate that the THz properties of VO₂ film was significantly affected by the thickness. Therefore, the thickness should to be precisely controlled to obtain reproducible and reliable performance. The THz devices based on VO₂ film may benefit significantly from these achievements.

The electronic structure and absorption spectrum of Ca₂SiO₄: Eu²⁺ was studied by using density functional theory. It is found that N atoms substituted provide many states around the Femi level, which leads to narrow optical band gap and interband transition originating from N2p to the Eu4f. In the N-doped Ca₂SiO₄: Eu²⁺ phosphor, Eu²⁺ ions experience a strong nephelauxetic effect and crystal field due to the coordinating nitrogen ions around the activated centers, which results in Eu4f and 5d states splitting. Thus, the red-shift of the absorption spectrum and high absorption band in the wavelength of 220-470 nm takes place for the N-doped Ca₂SiO₄: Eu²⁺ phosphor.