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A novel Eu3+doped fluorapatite red phosphor Ca2Y8(BO4)2(SiO4)4F2:Eu3+with pure phase was synthesized in this study. Density functional theory (DFT) calculation and diffuse reflection spectrum analysis reveal its potential as a matrix for phosphors excited by ultraviolet light. Eu3+has a 7F0→5L6transition at 394 nm, and the prepared phosphor exhibits a high emission intensity at 614 nm, which may be attributed to the 5D0-7F2energy transition at the lower symmetry site of Eu3+. The optimal doping concentration of the phosphor is determined to be 11 mol%, with concentration quenching attributed to the exchange interaction mechanism. The overall color purity of the phosphor is up to 99.88%, with an internal quantum efficiency as high as 91.15%. Notably, Ca2Y8(BO4)2(SiO4)4F2:11 mol%Eu3+(CYBSF:11 mol%Eu3+) phosphors exhibit good thermal stability, with a thermal quenching temperature (T1/2) of 552 K and the intensity of emission at 423 K still at 88.89% of that at 298 K. The activation energy of the phosphor is up to 0.30287 eV. Its comprehensive luminescence performance surpasses that of commercial red phosphor, making it suitable for near ultraviolet excited warm white light emitting diode (NUV-WLED) with a high color rendering index (Ra= 82) and a correlation color temperature (CCT) of 4339 K. Moreover, the phosphor achieves latent fingerprint visualization and anti-counterfeiting ink on different material surfaces: glass, aluminum foil, plastic and paper. Overall, the fluorapatite CYBSF:11 mol%Eu3+phosphor holds great potential for multimodal applications due to its high quantum efficiency and good thermal stability.

Y3Fe5O12(YIG) crystals are highly desirable for the fabrication of mid-infrared isolators with the rapid growth of optical communications, although it is rather challenging to grow large size and high-quality single crystals. Dy3+doping is expected to improve the optical and magneto-optical properties. However, high quality Dy:YIG crystals and the adjustment of Dy3+ on the structure and optical behavior of YIG crystal remain unclear, impeding its practical applications. Herein, a series of Y3–xDyxFe5O12(x = 0, 0.5, 1.0, 1.5, 3) solid solution crystals was grown by the flux-Bridgman method and single crystals up to 25 mm were obtained. With the introduction of Dy3+, lattice parameters are gradually enlarged from 1.2379 nm (YIG) to 1.2420 nm (DyIG). Typical Dy3+absorption peaks are observed around 1070, 1265 and 1670 nm. The refractive index decreases from 2.37 (500 nm) to 2.10 (2500 nm) for YIG crystal, and it reduces from 2.47 (500 nm) to 2.16 (2500 nm) for DyIG crystal. The optical bandgaps remain almost unchanged for Dy:YIG crystals. The optical dispersion of the refractive indices was finely fitted by the Wemple and DiDomenico (WDD) and the Sellmeier models, respectively. With the increase of Dy3+content, the saturation magnetization (Ms) decreases significantly from 23.62 emu/g (YIG) to 5.33 emu/g (DyIG). Small coercive field is persisted for this system, endowing small external magnetic field. These results provide valuable references for the manipulation of rare earths on the properties of magneto-optical crystals, which is beneficial to the design of high-performance garnet crystals for the application of optical switching and non-reciprocal related devices.

A series of new oxyapatite red phosphors Ca3Y7(BO4)(SiO4)5O doped with different concentrations of Eu3+were successfully synthesized by high temperature solid state method. The XRD rietveld refinement results show that the structure of the phosphor belongs to space group P63/mand Eu3+ion replaced Y3+ion. The emission spectrum consists of the characteristic emission peaks corresponding to Eu3+under the excitation of 274 nm and the dominant emission peak is at 614 nm (5D0→7F2of Eu3+). The concentration quenching effect occurs and the optimized Eu3+concentration is 4.0 mol%. The energy level diagram for luminous mechanism is also given and the non-radiative energy transfer mechanism between Eu3+is mainly exchange interaction. The CIE coordinate is close to the ideal red light and the color purity is higher than 99.79%. Moreover, the phosphor exhibits moderate thermal stability because the photoluminescence intensity at 423 K is still maintained at higher than 78.97% of that at room temperature. The internal quantum efficiency of Ca3Y7(BO4)(SiO4)5O:4.0 mol%Eu3+phosphor is 58.2%. A red LED device based on it can emit bright red light. The CCT values of the device are basically unchanged when driven by various bias current. The results show that Ca3Y7(BO4)(SiO4)5O:Eu3+is a new type of oxyapatite red fluorescent material with good comprehensive performances.