Sm3+-doped strontium barium borate phosphor for white light emission: Spectroscopic properties and Judd–Ofelt analysis

et al. 2021

Molecules

Rare-earth labeling in biological apatite could provide critical information for the pathologic transition (osteoclastic) and physiologic regeneration (osteogenesis) of bone and teeth because of their characteristic site-sensitive fluorescence in different coordinative conditions of various tissues in many biological processes. However, the rare-earth labeling method for biological apatites, i.e., carbonated-hydroxyapatite, has been rarely found in the literature. In this paper, we report a Pourbaix-diagram guided mineralizing strategy to controllable carbonation and doping of rare-earth ions in the hydroxyapatite (HA) lattice. The carbonation process of hydroxyapatite was achieved by controllable mineralization in hydrothermal condition with K2CO3 as the carbonate source, which results into the pure B-type carbonated hydroxyapatite (CHA) with tunable carbonate substitution degree. All of the as-synthesized materials crystalized into P63/m (No. 176) space group with the lattice parameter of a decreases and c increases with the increasing of carbonate content in the reactants. Structural refinement results revealed that the substitution of planar CO32− is superimposed on one of the faces of PO43− tetrahedral sub-units with a rotation angle of 30° in reference to c-axis. All of the hydrothermally synthesized CHA nanocrystals show hexagonal rod-like morphology with the length of 70–110 nm and diameter of 21–35 nm, and the decreasing length/diameter ratio from 3.61 to 2.96 from low to high carbonated level of the samples. Five rare-earth cations, of Pr3+, Sm3+, Eu3+, Tb3+, and Ho3+, were used as possible probe ions that can be doped into either HA or CHA lattice. The site-preference of Tb3+ doping is the same in the crystallographic site of HA and CHA according to characteristic emission peaks of 5D4–7Fj (j = 3–6) transitions in their photoluminescent spectroscopy. Our work provides a controllable carbonation method for rare-earth labeling hydroxyapatite nanomaterials with potential biologically active implant powders for bone repair and tissue regeneration.

Section: %mentioning

confidence: 56%

Section: %mentioning

confidence: 77%

Pourbaix-Guided Mineralization and Site-Selective Photoluminescence Properties of Rare Earth Substituted B-Type Carbonated Hydroxyapatite Nanocrystals

Liu

et al. 2021

Molecules

“…Figure 9 is the emission spectra of the samples after heat treatment at different times (12,24,36,48, and 60 h, respectively), they are all excited by near-ultraviolet light at 345 nm. There is a slight redshift of the emission peak, which is attributed to the energy transfer process caused…”

Section: Effects Of Heat Treatment On Optical Properties Of Ce-doped ...mentioning

confidence: 99%

“…Borophosphate-based glass has good optical properties, low refractive index, low dispersion, and good transparency from ultraviolet to near-infrared. [24][25][26] However, the poor thermal stability and chemical durability are the shortcomings. 27,28 Fluoride glass has ultralow melting point characteristics, but poor chemical stability, low mechanical strength, and so on.…”

Section: Introductionmentioning

confidence: 99%

Microstructures and luminescent regulation of Ce‐doped silicate glasses with high transmittance and thermal stability

Huang

Int J Applied Ceramic Tech

et al. 2021

The traditional model for wLEDs usually encapsulates the phosphor and resin mixture on the InGaN blue-emitting chip. However, the poor thermal stability of silicone resin will lead to the reduction of the luminescent intensity of the wLED devices. Glass has excellent thermal stability and transparency, which is a promising alternative to resins. In this work, Ce-doped silicate luminescent glasses have been developed by a high-temperature melting quenching method in air atmosphere. The luminescent intensity can be enhanced by increasing the heat treatment temperature and extending the heat treatment time in 10%H 2 /Ar atmosphere because Ce 4+ ions can be reduced to Ce 3+ ions. However, when the heat treatment temperature reaches 850 • C, the generation of precipitates in the glass can reduce the luminescent intensity. The transmittance of glass can reach 87%, and the highest luminous intensity obtained when heat treated at 800 • C.The glass transition temperature is 740 • C and the thermal conductivity of the glass is .95 W m −1 K −1 , which is about five times higher than that of resin. The results show that the emerging Ce-doped silicate luminescent glass could be the potential material for wLED applications.

“…1,11,12 However, YAG:Ce 3+ phosphors generally need to be mixed with an organic resin before being glued to the chip, 13 resulting in many fatal problems such as chemical unstability, 14 low thermal conductivity, 15 and easy to age 16 caused by the organic resin. Besides, despite YAG:Ce 3+ phosphors having been widely commercialized, the lack of red emission made this type of wLEDs have a low color rendering index (CRI), [17][18][19] high correlated color temperature (CCT), 20 and easy color shift, 21 which makes a terrible user experience.…”

Section: Introductionmentioning

confidence: 99%

Improving white light emission and quantum yield of Ce@Eu co‐doped silicate glass by reducing Eu³⁺ to Eu²⁺ with Si₃N₄

Huang

et al. 2022

J Am Ceram Soc.

Rare-earth-doped transparent glass shows great potential in white light-emitting diodes (wLEDs) application due to its excellent optical and luminous properties. Currently reported commercial wLEDs have a drawback in red emission missing, which leads to a relatively low color rendering index (CRI) and a relatively high correlated color temperature (CCT). In this work, Ce@Eu Sr-Si-O glass is fabricated using a high-temperature quenching method. The white light is available when the ratio of Ce 3+ /Eu 3+ equals 1, and the emitting color can be adjusted from blue to red by controlling the ratio of Ce 3+ /Eu 3+ . To further optimize the white light, Eu 3+ ions can be reduced to Eu 2+ according to the reaction of 6Eu 3+ + 2N 3− → 6Eu 2+ + N 2 ↑ by introducing Si 3 N 4 . As a result, the standard white light emission can be achieved in the Ce@Eu silicate glass contributed by the blue light from Ce 3+ , red light from Eu 3+ , and yellow-green light from Eu 2+ (two elements, three emission). This glass shows excellent luminous properties, such as a color coordinate is (0.3651, 0.3269) in CIE 1931 color coordinate diagram, a CRI is over 70, a high quantum yield of 36.02%, and a CCT of 4117 K.