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field. Compared with the traditional light source, it has the advantages of high brightness, environmental friendliness, long duration, and energy saving. [2] Nowadays, the universal method for obtaining white light is to combine a Y 3 Al 5 O 12 :Ce 3+ (YAG:Ce 3+ ) yellow phosphor with an InGaN blue LED chip. [3] Meanwhile, this approach suffers from poor colorrendering (R a < 75) and high correlated color temperatures (CCT > 4500 K) due to the lack of a red spectral component. [4] Another effective solution to realize the high-quality white light is the convergence of the n-UV chip with RGB (red, green, and blue) phosphors. [5] However, the strong re-absorption of blue light by the red and green phosphors actually causes obvious energy loss. [6] The single-phase white emitting phosphors are accepted as an appropriate material to avert the reabsorption problem. [7] In previous reports, energy transfer was considered as an easy way to obtain single-phase white emitting phosphors. However, in many cases, due to the deficiency of some light components, the CCT and R a parameters of the WLEDs devices were not ideal, and even get cold white light. [8] The cold white light is bad for the human eye, impeding the widespread application of WLEDs in some areas, such as offices, hospitals, and the home. [9] Generally, in addition to energy transfer, promising approaches for the optimization of luminescence properties mainly include doping level control, [10] cationic-anionic substitution, [3a,11] crystal-site engineering approach, [12] and mixing of the nanophase. [13] Effective structure regulation can improve the luminescent properties of phosphors, such as enhancing quantum efficiency (QE), [14] improving thermal stability, [3a] and color tuning. [15] Therefore, to optimize and design novel single-composition white-emitting phosphors materials, structural engineering is a feasible method.Due to the sensitivity of 5d orbitals to a crystal field environment, Eu 2+ -doped phosphors possess broad absorption and emission spectra, which is more suitable for application in WLEDs. [16] Among various rare-earth-activated luminescent materials, phosphates are extensively explored as hosts because of its low synthesis temperature and exceptional optical properties. [17] Up to now, all sorts of whitlockite-type β-Ca 3 (PO 4 ) 2 -based A series of Eu 2+ single doped Ca 9 Na 1-x Li x Sc 0.667 (PO 4 ) 7 phosphors with fullspectrum emission have been synthesized. Under the 385 nm excitation, the Eu 2+ single doped Ca 9 NaSc 0.667 (PO 4 ) 7 without Li + doping displays a broad cold white light emission with the peaks at about 480 and 610 nm. With the introduction of Li + ions, the Eu 2+ ions selectively occupy the Ca1, Ca2/Ca3, and Na sites. The variation of local environment of Eu 2+ ions caused by Li + ions enhances the luminous intensity, solves the problem of the lack of a red light component, and realizes the emission color tuning from cold white via warm white to orange. A special charge compensation method caused by Li + ...

Oxidative damage is an important contributor to the morphological and the functional changes in the development of osteoporosis. In this reported work, the use of cerium oxide (CeO 2 ) nanoparticles as a potential therapeutic agent for osteoporosis is explored. By using the primary osteoblasts (OBs) exposed to hydrogen peroxide (H 2 O 2 ), it is shown that the CeO 2 nanoparticles relieve the H 2 O 2 -induced oxidative damage. The protective effects of the CeO 2 nanoparticles were because of a reduction in the reactive oxygen species (ROS). The level of the antioxidant enzymes was increased after treatment with the CeO 2 nanoparticles in the OBs exposed to H 2 O 2 . Moreover, the cell apoptosis rate was decreased after treatment with the CeO 2 nanoparticles. The CeO 2 nanoparticles protect the OBs against the H 2 O 2 -induced oxidative damage, suppression of the antioxidant enzymes depletion and cell apoptosis via its ROS scavenging mechanism. The findings suggest that the CeO 2 nanoparticles may have a potentially therapeutic value for the diseases related to the ROS.

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Excellent luminous performance and high color rendering are the keys to white light-emitting diodes (WLEDs) illumination. This work reports a single-phase full-visible-spectra Y2Mg2Al2Si2O12(YMAS):Eu2+,Mn2+ phosphor for WLEDs with ultra-high color rendering....

Color-tunable phosphors can be obtained through codoping strategies and energy transfer regulation. Ce 3+ and Eu 2+ are the most common and effective activator ions used in phosphor materials. However, the energy transfer from Eu 2+ to Ce 3+ is rarely reported. In this work, Y 2 Mg 2 Al 2 Si 2 O 12 (YMAS):Eu 2+ ,Ce 3+ phosphors were successfully synthesized, which was confirmed by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Rietveld refinement, scanning electron microscopy (SEM) and element mapping images, and spectral information. The luminescent color of YMAS:Eu 2+ ,Ce 3+ phosphors could be tuned from blue to cyan to light green to yellow-green and finally to green-yellow, which was achieved by adjusting the energy transfer between different dopants. The energy transfer from Eu 2+ to Ce 3+ was confirmed by photoluminescence spectra and fluorescence decay curves. Within the experimental gradient, the energy transfer efficiency could reach up to 48%. At 373 K, the Y 1.99 Mg 1.99 Al 2 Si 2 O 12 :0.01Eu 2+ ,0.01Ce 3+ (YMAS:0.01Eu 2+ ,0.01Ce 3+ ) phosphor exhibited a total integral emission loss of only 8%, and the emission peak intensity decreased to 95%, indicating the excellent thermal stability. The white light-emitting diode (WLED) fabricated by the YMAS:0.01Eu 2+ ,0.01Ce 3+ phosphor has the same level correlated color temperature (CCT = 5841 K), greatly improved color rendering index (R a = 87.8), and higher quality white light color (CIE = (0.3258, 0.3214)) than the WLED made by the YMAS:0.01Eu 2+ phosphor, indicating that the performance of the phosphor was significantly improved by introducing Ce 3+ . This work provides an effective guide for the design and development of highly efficient color-tunable phosphors involving energy transfer from Eu 2+ to Ce 3+ in some specific materials, such as garnet structures.

A novel green-light-emitting silicon-based oxynitride phosphor Ca 4 Y 3 Si 7 O 15 N 5 :Eu 2+ with low thermal quenching and ideal pressure sensitivity is reported. The Ca 3.99 Y 3 Si 7 O 15 N 5 :0.01Eu 2+ phosphor can be efficiently excited by 345 nm ultraviolet light and shows very low thermal quenching (integrated and peak emission intensities at 373 and 423 K were 96.17, 95.86, and 92.73, 90.66% of those at 298 K, respectively). The correlation between high thermal stability and structural rigidity is investigated in detail. The white-light-emitting diode (W-LED) is assembled by depositing the obtained green-light-emitting phosphor Ca 3.99 Y 3 Si 7 O 15 N 5 :0.01Eu 2+ and commercial phosphors on a ultraviolet (UV)emitting chip (λ = 365 nm). The CIE color coordinates, color rendering index (Ra), and corrected color temperature (CCT) of the obtained W-LED are (0.3724, 0.4156), 92.9, and 4806 K, respectively. In addition, when subjected to in situ highpressure fluorescence spectroscopy, the phosphor exhibits an evident red shift of 40 nm with an increase in pressure from 0.2 to 32.1 GPa. The phosphor has the advantage of high-pressure sensitivity (dλ/dP = 1.13 nm GPa −1 ) and visualization with pressure changes. The possible reasons and mechanisms are deeply discussed in detail. Based on the above advantages, Ca 3.99 Y 3 Si 7 O 15 N 5 :0.01Eu 2+ phosphor is expected to have potential applications in W-LEDs and optical pressure sensing.