Phosphor Powders Research Articles

澱粉補強リン酸カルシウム骨ペーストへの異種カチオン種の導入

Bone cement is applied to bone detect caused by injury and disease. Our group has developed a novel bone paste by kneading a gelatinized wheat starch and calcium phosphate (CP) powders in which CaHPO4, Ca4(PO4)2O and β-Ca3(PO4)2 are equimolarly mixed. This bone paste is easily handled and can be set to form hydroxyapatite (HAp) under physiological conditions. On the other hand, previous literature reported that strontium ion can promote and regulate the activity of osteoblastic and osteoclastic cells in the living bone, respectively. In addition, copper ion is reported antibacterial performance. In this work, strontium and copper ions were fed into the bone paste as starting materials to promote cell activity as well as antibacterial properties. Paste samples were prepared by kneading a starch gelatinized with mixed powders of CP, α-SrHPO4 and Cu2+-substituted β-Ca3(PO4)2. Phase change, release behavior of metal cations and antibacterial properties were investigated. A paste sample immersed in Tris-buffered NaCl solution was set through forming HAp, and the amount of strontium ion released from the paste sample was a level expected to enhance the cell activity. However, all the pastes didn’t show antibacterial properties in spite of introducing of copper ion to the samples.

Impact of multi-pass friction stir alloying on the characterization of Mg based bio-ceramic nano composites

Multi-pass friction stir alloying is performed to incorporate bio-ceramic Nano-powders with MB3 magnesium alloy. The reinforcement bio-ceramic particles were hydroxyapatite (HA), tri-calcium phosphate (TCP) and aluminum oxide (Al2O3) Nano powders. The results revealed that the increased number of FSP passes caused a refinement in the grain structure, resulting in increasing average microhardness values in the stirred zone. Furthermore, all processed samples revealed tensile and yield strength values lower than that of the base material, with an enhancement in their ductility. While, the electrochemical impedance spectroscopy (EIS) results showed a higher radius capacitive loop of the 4-pass manufactured composites, and the best corrosion behavior was achieved at the 4-pass Mg-HA composite. Moreover, the potentiodynamic polarization (PDP) results showed lower current density with higher polarization resistance values (Rb) of the manufactured composites compared to the base material which reflects the improvement in the corrosion behavior. Moreover, the immersion test results displayed also lower corrosion rates of all processed samples, where the lowest corrosion rate was achieved at 4 passes Mg-HA composite with a reduction of about 27 % of the BM after 7 days of immersion in simulated body fluid (SBF).

Highly luminescent and thermostable R6G@DUT-52 composite for sensing Fe3+ ion and white light emitting diode

Introduction of the yellow rhodamine 6G (R6G) fluorescent dyes into the nanopores of DUT-52 has been successfully achieved the R6G@DUT-52 composite by the one-pot hydrothermal method. Its structure, stability and morphology are well characterized by the XRD, TGA and SEM, whose fluorescent properties are also studied in detail. The obtained R6G@DUT-52 exhibits the highly thermostability with the blue emission of the DUT-52 at 435 nm, the characteristic emission of R6G dyes at 568 nm and the highly quantum yields (QY) of 77.8%, which shows the potential application prospects as the probes for high selectivity and sensitivity of detecting Fe3+ ion from 12 kinds of metals ions. In addition, R6G@DUT-52 is cooperated with the commercial green phosphor powder (GGA) that is further encapsulated on the 455 nm blue LED chip to achieve the warm white light emitting diode (WLED) device with the CIE coordinates of (0.373, 0.364), correlated color temperature (CCT) of 4107 K and luminous efficiency (LE) of 113.08 lm/w.

Latest Advances in Narrow‐Band Phosphors and Their Role in Color Management

Latest Advances in Narrow‐Band Phosphors and Their Role in Color Management

Fabrication of nanocrystalline magnesium phosphate-based composite bioceramics using magnesium-containing phosphate glass as sintering additives

Magnesium-rich microenvironment is beneficial to both osteogenic and proangiogenic activities. To construct magnesium-rich microenvironment, the magnesium phosphate bioceramics could not be sintered at high temperatures, leading to low mechanical strength. In this study, magnesium phosphate-based composite (AMP/MPG) bioceramics were fabricated at low sintering temperatures (650 and 800 °C) using amorphous magnesium phosphate (AMP) and magnesium-containing phosphate glass (MPG) powders as starting materials. In the sintering of AMP/MPG, the MPG crystallized and reacted with AMP to form new phases. The AMP/MPG showed nanocrystals and pronouncedly higher compressive strength, in contrast with the bioceramics prepared from crystalline magnesium phosphate powders. The AMP/MPG continuously released high concentrations of magnesium ions, which accounted for the remarkably enhanced cell proliferation, osteogenic and angiogenic activities. The AMP/MPG bioceramics with high mechanical strength, osteostimulative and proangiogenic capacity were considered promising biomaterials to effectively regenerate the critical-size bone defects.

Combined recovery of valuable metals from LiFePO4–LiCoO2 system without adding oxidant and reductant

AbstractBased on the oxidation of ferrous ions in lithium iron phosphate and reduction of trivalent cobalt ions in lithium cobaltate, an innovative combined recovery process of lithium iron phosphate and lithium cobaltate powders is proposed. The effects of leaching conditions on leaching performance are studied and the optimal leaching conditions are obtained. Under these conditions, the leaching efficiencies of lithium and cobalt ions reach up to 99.92% and 81.11%, respectively. After removing ferric ions from leachate, the cobalt and lithium ions are separately recovered from the leaching solution. The final precipitation rate of cobalt ions is up to 97.71% with the purity of cobalt oxalate as 99.94%. In addition, the precipitation rate of lithium ions is 78.54% and the purity of lithium carbonate reaches up to 99.94%. Finally, the reaction path and mechanism for the combined recovery of lithium iron phosphate–lithium cobaltate system are preliminary investigated.

Performance improvement of the dry chemical-based fire extinguishers using nanocalcium silicate synthesised from biowaste

Herein, we investigated nanocalcium silicate (nCa2SiO4) prepared from clam shells and rice husks for its utilisation as a chemical agent in a fire-extinguishing mixture comprising ABC dry powder. The fire-extinguishing performance was evaluated with Class A and B fires. The prepared mixture was compared with commercial mono-ammonium phosphate powder based on different parameters, namely extinguishing time, amount of extinguishing agent used, fire temperature reduction rate, powder coating on the fuel and a reburn incident. It was found that the mixture of nCa2SiO4 and ABC dry powder could extinguish Class A and B fires within 10.67 and 9 s, respectively, while commercial mono-ammonium phosphate powder required 11 and 11.33 s to extinguish Class A and B fires, respectively. Thus, the mixture of nCa2SiO4 and ABC dry powder was more effective and less consumed as compared to commercial mono-ammonium phosphate powder (Class B only). This study demonstrates the efficacy of nCa2SiO4 to improve the performance of dry chemical-based fire extinguishers.

Identification of mercury species in spent fluorescent lamps and mercury recovery by distillation

The discarding of spent fluorescent lamps, one of the most significant sources of mercury usage in industry, might cause mercury release into the environment when suffering from breakage. The reclamation disposal of fluorescent lamps for mercury recycling is essential, while how to achieve highly efficient conversion of various mercury species into elemental mercury vapor is a key challenge. Herein, the distillation method was adopted for mercury recycling from phosphor powder. The results show that the contents of elemental mercury and oxidized mercury vapor filled in the lamps were 150–3500μg and 5–20μg, respectively. The mercury release sustained for 13(±2) h, with a maximum mercury concentration of 4500μg/m3. The mercury in phosphor can be desorbed to an undetected level when distilling at 600 °C under vacuum for 30 min, while that would be achieved at 700 °C when distilling under atmospheric pressure. This suggests that the vacuum distillation was favorable for the conversion of oxidized mercury into elemental mercury. The variation of mineral phase, particle size distribution and morphology of phosphor after distillation was insignificant, which guaranteed the recycling of phosphor simultaneously accompanying with mercury recycling. This work clarified the mercury release behavior during lamps crushing and provided a feasible way for mercury recycling.

Orange-red emitting MoO3:Sm3+ transparent nano-composite films for anti-counterfeiting and data secure applications

Poly(vinyl alcohol) (PVA) and chitosan (CS) based nanocomposites (NCs) filled by various weight percent of modified MoO3:Sm3+ (MS) nanoparticles (NPs). For the preparation, folic acid (FA) up to 150 mg were used via ultrasonication method then was cast to thin films. The changes in the structural properties of the prepared samples were examined by X-ray diffraction. FT-IR spectroscopy indicated the possible interactions of the MS NPs with the PVA/CS backbones through the absorption bands. MS NPs were homogeneously dispersed in the polymer matrix at nanoscale. The photoluminescence (PL) emission spectra of PVA/CS-MS NCs excited by 404 nm wavelength, with the key emission peaks centred at ∼ 563, ∼600 and ∼ 647 nm are mainly attributed to transitions from 4G5/2→6H5/2, 4G5/2→6H7/2, 4G5/2→6H9/2 respectively. The powder dusting method was used to visualize the latent fingerprints (LFPs) on various surfaces under 404 nm excitation. Additionally, PVA/CS matrix was masked on the developed fingerprints (FPs) for long term storage. The results clearly indicated that, the level 1–3 ridge features were stable up to 180 days with superior contrast and sensitivity. The optimized phosphor powder is used to fabricate unclonable security ink and brush mode technique was used to mark on various surfaces and exposed to UV 404 nm light. The results revealed that the present phosphor can garner significant interest for the use in personal identification and security encoding.

Synthesis by solid route and physicochemical characterizations of blends of calcium orthophosphate powders and mesoporous silicon particles.

The purpose of the study was to investigate the synthesis of economic calcium phosphate powders from recycled oyster shells, using a ball milling method. The oyster shell powder and a calcium pyrophosphate powder were used as starting materials and ball milled, then heat treated at 1,050°C for 5h to produce calcium phosphate powders through a solid-state reaction. Electrochemically synthesized mesoporous silicon microparticles were then added to the prepared phosphate powders by mechanical mixer. The final powders were characterized using X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy to analyze their chemical composition and determine the most suitable process conditions. The biocompatibility of the produced powders was also tested in vitro using murine cells and the results showed good biocompatibility.

Microwave-assisted synthesis of GdOF: Eu3+/Tb3+ ultrafine phosphor powders suitable for advanced forensic and security ink applications

The rare-earth-doped inorganic ultrafine oxyfluoride host matrices in forensic science, especially in latent fingerprint detection and anti‐counterfeiting applications, were still unexplored and may replace the existing technology owing to its high sensitivity. Herein, GdOF: Eu3+/Tb3+ ultrafine red and green phosphors were synthesized via a rapid, green microwave-assisted hydrothermal method at 150 °C. The phosphors synthesized by this novel method possess good luminescent intensity for the hypersensitive 5D0→7F2 transition of Eu3+ and 5D4→7F5 transition of Tb3+ ions as compared to the phosphors prepared via other conventional methods such as co-precipitation synthesis, sol–gel synthesis, and microwave-assisted co-precipitation synthesis. Further, an enhancement in the luminescent intensity of the ultrafine phosphor was noticed when the microwave parameters and pH values were tuned. The optimized red and green phosphors having high luminescence intensity, good color purity, and high quantum yields of 89.3%, and 71.2%, respectively, were used for the visualization of latent fingerprints on various substrates. These promising phosphors exhibited excellent visualization regardless of the background interference and limit the risk of duplication and are highly reliable. The security inks developed using these phosphors are highly efficient for anti-counterfeiting applications. These multifunctional properties of investigated phosphors can be explored for security applications.

Enhancement on Tb3+ luminescence in CaScBO4-based ceramic phosphors by Ce3+-induced resonance energy transfer and the generation of white light emission collaborated with Mn2+

A series of Tb3+-doped, Ce3+,Tb3+-co-doped and Ce3+,Tb3+,Mn2+-tri-doped CaScBO4 (CSB) ceramic phosphors were prepared by solid-state reaction. X-ray diffraction (XRD) was taken to confirm the phase purity of all as-prepared phosphors powder. Steady-state and transient-state fluorescence spectra were applied to evaluate the luminescence properties of the phosphors. The results indicated that significant enhancement on Tb3+ luminescence was successfully realized by the Ce3+-induced resonance energy transfer and confirmed that the energy transfer from Ce3+ to Tb3+ was governed by an electronic dipole-dipole interaction. Compared to the CSB:Tb3+ phosphors whose optimal excitation located at 378 nm, the occurrence of Ce3+-Tb3+ energy transfer not only allowed the optimal excitation to peak at around 390 nm but also gifted the CSB:Ce3+,Tb3+ phosphors color tunability from blue, cyan to green. Then, two different designs of white light by the introduction of Mn2+ luminescence were performed. One was the combination of CSB:Ce3+,Tb3+ and CSB:Ce3+,Mn2+ phosphors, based on the co-excitation of the above two phosphors at the same wavelength. Another was the direct use of the tri-doped CSB:Ce3+,Tb3+,Mn2+ phosphors. Both designs succeeded in the generation of white light emission. The performance of these two designs in real devices were also studied. The direct use of the tri-doped CSB:Ce3+,Tb3+,Mn2+ phosphor in white light-emitting diode (WLED) device can produce white light with a color rendering index (CRI) up to 85.3 while the use of the CSB:Ce3+,Tb3+ and CSB:Ce3+,Mn2+ phosphors combination can just produce a value of 76.6 in CRI.

Highly selective and green recovery of lithium ions from lithium iron phosphate powders with ozone

Highly selective and green recovery of lithium ions from lithium iron phosphate powders with ozone

Chemical Synthesis and Characterization of Hydroxyapatite Prepared from Cypraea Annulus

In the last decade, the processes involved in biomineralization has greatly developed, leading to the production of a new generation of biomaterials. Calcium phosphate ceramic materials attract special interest due to their bioactive and biocompatible properties in biomaterials. Most of marine structures contains calcium carbonate (calcite or aragonite) and they can be easily converted to bioceramic material. The application of calcium phosphate ceramics as useful biocompatible materials largely depends on the purity and morphology of the powder. In this study calcium phosphate bioceramics (as raw materials for bone-scaffolds) were obtained via hot-plate, ultrasound-assisted, and microwave assisted method using the sea shell Cyprae Annulus as a calcium source. The characterization of the produced materials was carried out via FT-IR, SEM, XRD analysis. It was found that the calcium phosphate powders (hydroxyapatite) produced by three different methods were predominantly monetite and hydroxyapatite as the secondary phase. According to the SEM results, the overall morphology for CaP powder bioceramics shows the regular distribution of spherical and rice-shaped and CP powders produced by microwave assisted method have better morphology. The used methods are safe and inexpensive. Moreover, the raw materials (Cypraea Annulus) feature the advantages of the unlimited source as well as the biological origin. These methods were compared takes attention due to it is economical and easy method to obtain hydroxyapatite.

Ciprofloxacin-Loaded Composite Granules Enriched in Silver and Gallium Ions—Physicochemical Properties and Antimicrobial Activity

Various calcium phosphates (hydroxyapatite, α- and β-tricalcium phosphate, and brushite) containing silver or gallium ions were synthesized via standard methods and subjected to physicochemical analysis by Fourier transform infrared spectroscopy (FT-IR), powder X-ray diffractometry (PXRD), and atomic absorption spectrometry (AAS). In the next step, the obtained calcium phosphate powders, sodium alginate, and chondroitin were used to produce composite granules. Ciprofloxacin, a broad-spectrum antibiotic that can be used in local delivery systems targeting bone tissue, was loaded into the granules. The release of silver and gallium ions as well as ciprofloxacin was then examined by inductively coupled plasma mass spectrometry (ICP-MS) and high-performance liquid chromatography (HPLC), respectively. The cytotoxicity of the granules was studied using a neutral red uptake (NRU) test and mouse embryonic fibroblasts. Moreover, preliminary antibacterial activity against Staphylococcus aureus and Escherichia coli was measured. The study showed that the type of calcium phosphates enriched in silver or gallium significantly affects the release profile of these ions. Biphasic calcium phosphates also have an impact on the morphology of the granules. Most of the granules turned out to be non-toxic to mammalian cells. Microbiological tests showed high antibacterial activity against both strains of bacteria.

Rational Design and General Synthesis of High-Entropy Metallic Ammonium Phosphate Superstructures Assembled by Nanosheets.

Three-dimensional (3D) superstructure nanomaterials with special morphologies and novel properties have attracted considerable attention in the fields of optics, catalysis, and energy storage. The introduction of high entropy into ammonium phosphate (NPO·nH2O) has not yet attracted much attention in the field of energy storage materials. Herein, we systematically synthesize a series of 3D superstructures of NPOs·nH2O ranging from unitary, binary, ternary, and quaternary to high-entropy by a simple chemical precipitation method. These materials have similar morphology, crystallinity, and synthesis routes, which eliminates the performance difference caused by the interference of physical properties. Subsequently, cobalt-nickel ammonium phosphate (CoxNiy-NPO·nH2O) powders with different cobalt-nickel molar ratios were synthesized to predict the promoting effect of mixed transition metals in supercapacitors. It is found that the CoxNiy-NPO·nH2O 3D superstructures with a Co/Ni ratio of 1:1 show the best electrochemical performance for energy storage. The aqueous device shows a high energy density of 36.18 W h kg-1 at a power density of 0.71 kW kg-1, and when the power density is 0.65 kW kg-1, the energy density of the solid-state device is 13.83 W h kg-1. The work displays a facile method for the fabrication of 3D superstructures assembled by 2D nanosheets that can be applied in energy storage.

Aqueous degradation and atomic layer deposition (ALD) stabilization of BaAl2O4: Eu2+, Dy3+ long afterglow phosphors

This paper presents the aqueous degradation mechanisms of BaAl2O4:Eu2+, Dy3+ phosphors and demonstrates an ability to prevent degradation via Al2O3 nano encapsulation of powders by atomic layer deposition (ALD) technique. Phosphor powder is synthesized from the solid-state reaction method. The aqueous degradation of this phosphor is systematically studied. This phosphor is found to hydrolyze and degrade within just 30 min of exposure in water. The degradation of BaAl2O4 host lattice directly affects the blue-green light emission at 497 nm, producing blue- and red-emissions that are peaked at 429 nm and 687 nm, respectively. Hydrated and structural decomposed BaAl2O4 reveals a continuous change in the phase assemblage over 30 days of immersion. To prevent this rapid degradation, use of a protective nanocoating was investigated. 10 nm Al2O3 coatings were applied to the surface of the phosphor powder via ALD. ALD coated BaAl2O4:Eu2+,Dy3+ phosphor retains its phosphorescence for at least 7 days of water exposure. Successful encapsulation of such phosphor particles will make them possible to use in aqueous applications or store in long-term humid environments.

A cost-effective intense blue colour cobalt doped gahnite pigment for latent finger print, cheiloscopy and anti-counterfeiting applications

Alanine is used as a novel fuel in the solution combustion method (SCS) to produce nanocrystalline Co2+ (0.25–5 mol%) doped gahnite (ZnAl2O4: ZAO) nano pigments (NPs). A thorough investigation was conducted to comprehend the interaction of dopant (Co2+) and ZAO host matrix, as well as the influence of doping on their structural, optical, and luminescence properties. The powder samples were thoroughly characterized using XRD, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Photoluminescence (PL) spectroscopic techniques. SEM micrographs of clearly exhibit the formation of dense particles, voids, and pores in the sample. In addition, tiny aggregates were detected on the surface of more prominent clusters. The nominal composition of Zn, Al, Co and O was assessed using Energy Dispersive X-Ray Analysis (EDS). The optimized ZAO:5Co2+ phosphor powder demonstrated levels 1–3 fingerprint (FP) features and groove patterns (types 1–5) of lip print that can be clearly recognised, with excellent resolution and contrast, under 320 nm UV light. The appropriate thickening agent and defoamer were added to blue pigment during fabrication to generate anti-counterfeiting (AC) inks that mark on multiple surfaces with high resolution without spreading or tracing. The preceding results suggest that the ZAO:Co2+ NPs can serve as a significant candidate for the detection and individualization of latent fingerprints (LFP), lip prints (LP) and anti-counterfeiting applications.

Study on selective recovery of lithium ions from lithium iron phosphate powder by electrochemical method

In recent years, electric vehicle is greatly flourishing, while lithium iron phosphate batteries are vigorously developed due to their low cost and high stability. Since it is expected that the first batch of lithium iron phosphate (LFP) batteries will be retired at the peak in 2025, it is crucial to develop an environmentally and efficient recycling method. In this study, an acid-assisted electrochemical extraction method of lithium ions from LFP powder was proposed. Part of the LFP powder was leached directly by acid, and the leached ferrous ions were separated by oxidation precipitation and electroplating. The remaining LFP powder was directly oxidized by the anode to release lithium ions. The leaching efficiency of lithium ion reached up to 99.89 % and the leaching efficiency of iron ion was kept at a very low value of less than 0.2 %. The selective separation of lithium ion can be efficiently achieved during the leaching process. After evaporation and concentration, the lithium ions were recovered as product of high-purity lithium phosphate. Compared with other recycling methods, the proposed recovery method used less reagents and generated little waste. This process presents a novel green recycling pathway for the potentially selective leaching and recovery of spent LFP batteries.

Anti-thermal quenching in phytochrome-active AC-Driven electroluminescence from β-Ga2O3:Cr3+ powder phosphor

β-Ga2O3, a wide bandgap oxide material, has attracted recently scientific attention in optoelectronics, especially electroluminescent (EL) devices. It is good as a host material for transition metals and rare-earth elements. Herein, a NIR emitting alternating current (AC)-driven powder-based electroluminescent (PEL) device is introduced with superior thermal stability from a β-Ga2O3:Cr3+ phosphor. It consists of β-Ga2O3:Cr3+ and BaTiO3 layers that serve as active and insulating layers, respectively, which are fabricated by a facile and cost-effective screen-printing method on the ITO glass substrate. Under the AC source, it emits the NIR spectrum, which is optically attributed from the spin-allowed and spin-forbidden transitions of Cr3+ ions and well overlapped with the phytochrome absorption spectrum. The strategies to obtain the optimum condition of the phosphor for EL purposes are presented with parameters of annealing temperatures as well as Cr3+ concentrations. Further analysis shows a promising application in harsh environments with thermal stability, so-called, anti-thermal quenching phenomenon up to 200 °C (473 K). This work can provide a worthwhile realization and method of large-area NIR emitting devices based on the β-Ga2O3 phosphor.