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Tb3+-doped Al2O3–B2O3–SrO glass was prepared by the melt annealing method, and the crystallization kinetics of the glass was studied by the thermal analysis method. The crystallization activation energy of the glass was calculated by the Kissinger method and the Ozawa method, the values of which were 271.83 ± 8.56 kJ mol−1 and 260.72 ± 8.20 kJ mol−1, respectively. Optical band gap and Urbach energy of Tb3+-doped glass and glass ceramic were calculated by absorption spectra. The results indicate that after heat treatment, the optical band gap of the glass ceramic is reduced compared to that of the glass. The emission intensity of Tb3+ in the glass ceramic is enhanced compared with that in the glass. Variable-temperature emission spectra show abnormal thermal quenching of Tb3+-doped glass and glass ceramic. The results show that Al2O3–B2O3–SrO glass ceramics doped with Tb3+ have high luminescence intensity and can be applied to green light emitting devices and display devices. [ABSTRACT FROM AUTHOR]

The Sm3+/Eu3+ doped transparent glass ceramics (GCs) containing Na7.15(Al7.2Si8.8O32) crystallite were successfully prepared by melt crystallization. Combined with differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscope (SEM) and light transmittance curve, so the best heat treat condition of GCs is 560 °C for 2 h. According to the emission spectrum, the appropriate doping concentration of Sm3+ and Eu3+ is determined to be 0.3% and 0.7%, respectively. The decrease of fluorescence lifetime of Sm3+ confirms the energy transfer (ET) from Sm3+ to Eu3+. The critical distance between Sm3+ and Eu3+ is 5.15 nm, and the mechanism of ET is electric multipole interaction. The chromaticity coordinates are calculated according to the emission spectrum, and luminescence color of GCs is in red region. So the Sm3+/Eu3+ co-doped containing Na7.15(Al7.2Si8.8O32) crystallite GCs is a promising red luminescent material. [ABSTRACT FROM AUTHOR]

Tb3+‐doped and Eu3+/Tb3+ co‐doped transparent glass ceramics containing Na3Gd(PO4)2 crystal phase were prepared by melt crystallization. The types of crystals, grain size, and optical transmittance of the samples were investigated by X‐ray diffraction (XRD), scanning electron microscope (SEM), and UV visible absorption spectrometer. The effect of different heat treatment time on grain size, crystal morphology, and light transmittance was also studied. The luminescence performance of transparent glass ceramics was systematically studied by the excitation spectrum, emission spectrum, and the fluorescence lifetime. The optimal doping concentration of Tb3+ doped and Eu3+/Tb3+ co‐doped were determined. When the mole percent concentration of Tb4O7 was 0.4%, the strongest green light was obtained at 546 nm (5D4 → 7F5). Meanwhile, the energy transfer process between Eu3+ and Tb3+ was discussed. Under the excitation of 374 nm, white light can be obtained by adjusting the concentration ratio of Eu3+ and Tb3+. [ABSTRACT FROM AUTHOR]

Transparent glass ceramic with Ba 2 NaNb 5 O 15 as the main crystal phase was prepared, and the appropriate heat treatment condition was selected as 710 °C/150 min through various characterizations. The luminous intensity and thermal stability were enhanced significantly when the glass ceramic was used as the luminous matrix. After introducing Ti4+ ions as charge compensators, the luminescence performance and thermal stability were further improved, and the reasons for this were analyzed. At 458 K, the luminous intensity of 0.5%Eu3+ doped glass ceramic containing 0.5%Ti4+ can maintain about 65% of room temperature with a chromaticity shift of 5.16 × 10−2. The relative and absolute sensitivities of 0.7%Er3+ doped glass ceramic were 4.04 × 10−3 K−1 and 1.31% K−1. Introducing Ti4+ ions would weaken the population redistribution ability of 2H 11/2 and 4S 3/2 levels and reduce the temperature sensitivity. However, the sample containing Ti4+ shows good thermal stability, its green emission at 458 K has a small chromaticity shift of 6.45 × 10−3. The research shows that the glass ceramic can be used as a good luminescent host material, and Eu3+/Er3+ doped glass ceramic can be used in the fields of LEDs or temperature sensing. [ABSTRACT FROM AUTHOR]

Er 3+ /Yb 3+ co-doped transparent glass ceramics containing Na 3.6 Y 1.8 (PO 4 ) 3 crystals were prepared by high-temperature melting and subsequent heat treatment the precursor glass, and their up-conversion luminescent properties were investigated. The optimum heat treatment condition of glass at 630 °C for 2 h were determined by a series of experimental results, and confirmed the existence of Na 3.6 Y 1.8 (PO 4 ) 3 crystals in glass ceramics. The up-conversion luminescence spectra of the glass ceramic samples under pulsed excitation at 980 nm revealed luminescence bands corresponding to Er 3+ ion transitions in the green ( 4 F 7/2 - 4 I 15/2 , 2 H 12/2 - 4 I 15/2 , 4 S 3/2 - 4 I 15/2 ) and red ( 4 F 9/2 - 4 I 15/2 ) spectral regions. The fluorescence spectra reaches a maximum when the molar ratio of Er 2 O 3 to Yb 2 O 3 is 1:7. Luminescence quantum yield of the samples was measured by using an integrating sphere. The transmission spectra proved that the glass ceramics sample still maintained a high transparency up to 83% in the visible region. [ABSTRACT FROM AUTHOR]

By melt annealing technique, Er3+-Yb3+ co-doped precursor glass (PG) was prepared. Glass ceramics (GCs) containing KZnPO 4 crystal phase with tridymite structure were obtained by heat treatment of PG. The optimum heat treatment conditions of GCs are 670 °C for 60 min. Under these conditions, the average grain size of GC is about 205 nm, and the light transmittance in the visible region is about 80%. Through the analysis of the Rietveld refinement results of XRD, the lattice constants a and b of KZnPO 4 crystal decreased from 18.155 Å to 18.109 Å, and c decreased from 8.504 Å to 8.451 Å. Therefore, it is inferred that Er3+ and Yb3+ replace the Zn2+ in the lattice. The green up-conversion luminescence of GC is about 10 times that of PG excited by 980 nm laser. The optimal doping concentrations of Er3+ and Yb3+ in GCs are 0.5% and 1.0%, respectively. The calculation results of chromaticity coordinates show that Er3+-Yb3+ co-doped GCs with KZnPO 4 crystal phase is a promising green up-conversion luminescent material. • Er3+-Yb3+ doped transparent glass-ceramics containing KZnPO 4 crystal phase were prepared. • The light transmittance of glass-ceramic in the visible range can reach 80%. • The green up-conversion emission of glass-ceramics was about 10 times higher than that of precursor glass. • The color purity of 0.5%Er3+-1.0%Yb3+ co-doped glass-ceramic can reach 88.51%. [ABSTRACT FROM AUTHOR]

Tb3+-Yb3+ co-doped transparent glass ceramics (GCs) containing Y 2 Ti 2 O 7 crystal phases were synthesized by the melt crystallization. The light transmittance of GCs in the visible region reached 78%, and the average grain size was 278 nm under the optimal heat treatment conditions (720 °C/2 h). The GCs exhibited greater up-conversion luminescence intensity than precursor glass, and the reason for this result was explained in accordance with the Judd-Ofelt theory. Moreover, the introduction of Li+ did not change the crystalline phase of GCs. The emission intensity of the green light of the 8% Li + doped GCs was significantly enhanced by nearly 4.48 times under 980 nm excitation. The XRD refinement results suggest that the enhanced luminescence intensity is correlated with the change of the Y 2 Ti 2 O 7 crystal lattice caused by Li+ doping. The relevant luminescence mechanism was elucidated. The results suggest that Li+ doped transparent GCs open novel avenues for green UC applications. [ABSTRACT FROM AUTHOR]

A series of NaGd(MoO 4) 2 glass ceramics containing Eu3+-Tb3+ were fabricated using the melt-curing crystallization method. These glass ceramics were subjected to various analyses, such as differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM), and light transmittance curve analysis, to determine the optimal heat treatment conditions, which were determined to be 680 ℃/1.5 h. The XRD Rietveld analysis results confirmed the successful incorporation of Eu3+ and Tb3+ ions into the NaGd(MoO 4) 2 lattice structure. Moreover, the glass ceramics exhibited a smaller optical bandgap than the precursor glass, as observed by absorption spectroscopy. The energy transfer from Tb3+ to Eu3+ was demonstrated through the excitation spectra, emission spectra, and fluorescence decay curves. The primary mechanism responsible for this energy transfer was identified as a dipole dipole interaction. The ability to produce multicolor tunable emission was achieved by varying the Eu3+ doping concentration at a fixed Tb3+ concentration. The fluorescence intensity ratio and temperature dependence of Tb3+ and Eu3+ were used to calculate the relative sensitivity (S r), which reached a maximum of 3.34 % K−1 at 458 K. In conclusion, Eu3+-Tb3+ co-doped glass ceramics have promising potential for application in the fields of light-emitting diodes and temperature sensing. • Eu3+-Tb3+ co-doped NaGd(MoO 4) 2 glass ceramics were prepared. • The transmittance of glass ceramic can reach 80 % in the visible region. • The maximum relative sensitivity of the glass ceramics were obtained to be 3.34 % K−1 at 458 K. [ABSTRACT FROM AUTHOR]

Ho3+-Yb3+ co-doped transparent glass ceramics containing Sr 3 Gd(PO 4) 3 were successfully prepared by the melt crystallization method. The best condition of the thermal treatment was determined to be 780 °C/3 h by differential scanning calorimetry (DSC), X-ray diffraction (XRD) and scanning electron microscope (SEM). The transmittance of glass ceramic was approximately 81% in the visible region. From to the up-conversion emission spectra, the strong green emission (543 nm), weak red (654 nm) and blue emission (483 nm) due to the 5F 4 /5S 2 , 5F 5 , 5F 3 → 5I 8 transitions of Ho3+ can be observed. In addition, the optimum doping concentration of Ho 2 O 3 and Yb 2 O 3 was 0.3% and 0.8%, respectively. By comparing 0.3%Ho 2 O 3 -0.8%Yb 2 O 3 co-doped with 0.3%Ho 2 O 3 doped glass ceramic, the green and red up-conversion luminescence intensity were improved by about 33 times and 21 times, respectively. These results indicated that Ho3+-Yb3+ co-doped transparent glass ceramic containing Sr 3 Gd(PO 4) 3 have potential applications in the field of green up-conversion luminescence. The Ho3+/Yb3+ co-doped containing Sr 3 Gd(PO 4) 3 was successfully prepared. The introduction of Yb3+ can significantly enhance luminescence intensity and the Ho3+/Yb3+ co-doped glass ceramics containing Sr 3 Gd(PO 4) 3 has potential application value in up-conversion green light materials. [Display omitted] • The Ho3+/Yb3+ co-doped glass ceramic containing Sr 3 Gd(PO 4) 3 is synthesized. • The transmittance of glass ceramic can reach 81% in the visible region. • The critical distance of Ho3+-Yb3+ is 2.82 nm. • The introduction of Yb3+ can significantly enhance luminescence intensity. [ABSTRACT FROM AUTHOR]

• Er3+-Yb3+ doped glass ceramic containing NaBi(MoO4) 2 is synthesized. • The effect of Er3+ incorporation on the deviation angle of diffraction peak is discussed. • The up-conversion luminescence properties of Er3+-Yb3+ glass ceramics is studied. The molybdate precursor glass was prepared by the melting-annealing method. After heat treatment of the precursor glass, the glass ceramics containing NaBi(MoO 4) 2 crystal phase were successfully synthesized. The transmittance of the precursor glass and glass ceramics and up-conversion emission spectra at 980 nm were measured and analyzed. The effect of Er3+-Yb3+ doped concentration on the up-conversion luminescence intensity of glass ceramic samples was studied, and finally the best doped concentrations of Er3+ and Yb3+ were 0.6% and 1.0%, and the doped concentration ratio is 3:5. The Er3+-Yb3+ co-doped transparent glass ceramics containing NaBi(MoO 4) 2 have potential applications in green up-conversion luminescence. [ABSTRACT FROM AUTHOR]

Tb3+‐doped and Eu3+/Tb3+ co‐doped transparent glass ceramics containing Na3Gd(PO4)2 crystal phase were prepared by melt crystallization. The types of crystals, grain size, and optical transmittance of the samples were investigated by X‐ray diffraction (XRD), scanning electron microscope (SEM), and UV visible absorption spectrometer. The effect of different heat treatment time on grain size, crystal morphology, and light transmittance was also studied. The luminescence performance of transparent glass ceramics was systematically studied by the excitation spectrum, emission spectrum, and the fluorescence lifetime. The optimal doping concentration of Tb3+ doped and Eu3+/Tb3+ co‐doped were determined. When the mole percent concentration of Tb4O7 was 0.4%, the strongest green light was obtained at 546 nm (5D4 → 7F5). Meanwhile, the energy transfer process between Eu3+ and Tb3+ was discussed. Under the excitation of 374 nm, white light can be obtained by adjusting the concentration ratio of Eu3+ and Tb3+. [ABSTRACT FROM AUTHOR]

• Sm3+, Eu3+ doped NaNbO 3 glass ceramics were prepared and red light emission was realized. • The energy transfer efficiency was 49.44 % for 0.8 % Sm3+, 1.0 % Eu3+ doped NaNbO 3 glass ceramics. • The color purity was 95.7 % for 0.8 % Sm3+, 1.0 % Eu3+ doped NaNbO 3 glass ceramics. • The thermal quenching activation energy of glass ceramics was 0.236 eV and color offset value was 1.83 × 10−3, indicating good thermal and color stability. The lack of red light in commercial white LEDs limits the application in solid-state lighting. So preparing high-performance red luminescent materials is currently the main challenge. In this study, a series of Sm3+, Eu3+ co-doped glass ceramics containing NaNbO 3 crystalline phase were successfully prepared using the melt-curing-crystallization method. By differential scanning calorimetry analysis, X-ray diffraction analysis, scanning electron microscopy analysis and light transmittance analysis, the optimal heat treatment conditions for glass ceramics were determined to be 570 °C for 90 min. With the increase of Eu3+ concentration, the emission peaks of Sm3+ at 565 nm, 602 nm and 649 nm gradually decreased, indicating that there was energy transferred between Sm3+ and Eu3+. The emission intensity of the 0.8 mol% Sm3+, 1.0 mol% Eu3+ co-doped NaNbO 3 glass ceramics at 438 K still reaches 87 % of room temperature. Sm3+, Eu3+ co-doped NaNbO 3 glass ceramics have potential application value in the field of white LEDs. [ABSTRACT FROM AUTHOR]

Eu 2 O 3 doped transparent glass-ceramics containing NaY(MoO 4) 2 crystalline phase were prepared via melting-crystallization. The optimum heat treatment condition (660℃/3h) was determined by DSC, XRD, SEM and transmittance curves. The transmittance of glass-ceramic can reach 80 % in the visible region. The emission spectra of Eu 2 O 3 doped glass-ceramics consist of Eu3+ ions characteristic emission peaks at 591nm (5D 0 →7F 1) and 614nm (5D 0 →7F 2). The optimal doping concentration of Eu 2 O 3 in the glass-ceramics is 0.9 mol%, and fluorescence lifetime is 1.37042ms. The change of the ratio of red emission intensity to orange emission intensity leads to the shift of chromaticity coordinates from orange to red region, and the chromaticity coordinate (0.6337, 0.3635) of 0.9 mol% Eu 2 O 3 doped glass-ceramic is closest to the standard red light coordinate. The results show that this kind of glass-ceramic is expected to be good red emission material. [ABSTRACT FROM AUTHOR]

• The Ho3+-Yb3+ doped glass ceramic containing LaTiO 3 was synthesized. • The transmittance of glass ceramic can reach 79% in the visible region. • The color purity of 0.20 %Ho3+-0.30 %Yb3+ co-doped glass ceramics reaches up to 98.03 %. By using melt solidification crystallization method, Ho3+-Yb3+ co-doped transparent glass ceramics (GCs) containing LaTiO 3 microcrystal were successfully prepared. The structure of the GCs was characterized by X-ray diffraction (XRD), which proved that LaTiO 3 microcrystal was precipitated in the precursor glass (PG). The structures of PG and GCs were studied by infrared spectrum, which showed that a new absorption peak appeared in the GCs, which was attributed to the stretching vibration of the Ti-O bond in the [TiO 6 ] octahedral group, and it further demonstrated the precipitation of the LaTiO 3 microcrystal. By studying the up-conversion luminescence (UCL) properties, it is found that there were three emission peaks at 546, 652 and 484 nm, which are attributed to the 5F 4 /5S 2 → 5I 8 , 5F 5 → 5I 8 and 5F 3 → 5I 8 transitions of Ho3+, respectively, and the optimal doping concentrations of Ho3+ and Yb3+ were determined. The chrominance coordinate of Ho3+-Yb3+ co-doped glass ceramic (GC) is situated in the green light area and the color purity is as high as 98.03 %. The researches above show that Ho3+-Yb3+ co-doped GCs with LaTiO 3 microcrystal have a wide application prospect in green luminescence. [ABSTRACT FROM AUTHOR]

The Tb 3+ /Yb 3+ co-doped BaO-WO 3 -SiO 2 glass ceramic is prepared by melt crystallization method. The optimum heat treatment schedule is determined on basis of differential scanning calorimetry. The crystal phase is BaWO 4 by X-ray diffraction analysis. The crystal grain sizes are examined by scanning electron microscope and crystal grain sizes increase with the increasing of heat treatment time. In the visible region, the transmittance of glass ceramic is 79%. The up-conversion fluorescence intensity increase with the increasing of heat treatment time up to 90 min and with the increasing of Yb 3+ concentration up to 0.3 mol%. The possible mechanism of up-conversion in Tb 3+ /Yb 3+ co-doped BaWO 4 glass ceramic is discussed. [ABSTRACT FROM AUTHOR]

Er 3+ doped and Er 3+ –Yb 3+ co-doped ZnO–WO 3 –B 2 O 3 –SiO 2 glass-ceramics have been prepared by melt-crystallization method and their properties are examined by differential scanning calorimetry (DSC), scanning electron microscopy (SEM), X-ray diffractometry (XRD) and fluorescence spectroscopy. The results reveal that Er 3+ ions or Er 3+ –Yb 3+ ions have already entered into the crystalline field. The up-conversion mechanism of Er 3+ –Yb 3+ co-doped ZnO–WO 3 –B 2 O 3 –SiO 2 glass ceramics is analyzed, and the effect of Yb 3+ concentration on the intensity of up-conversion is investigated. With the increase of pump power, the intensity of green emission at 530 nm increases faster than that at 552 nm. The fluorescence spectrum reaches a maximum when the molar ratio of Er 2 O 3 to Yb 2 O 3 is 1:7. [ABSTRACT FROM AUTHOR]

Dy 2 O 3 -doped transparent glass-ceramics containing Ca 2 Ti 2 O 6 crystal phase were synthesized by melting crystallization method. The optimum heat treatment condition was determined to be 710 °C/1.5 h by differential scanning calorimetry (DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmittance curves. The optimal doped concentration of Dy 2 O 3 is 0.4 mol%. The effects of doping with different concentrations of Mg2+ and Sr2+ on the fluorescence intensity of glass-ceramics were discussed. In comparison to Sr2+, the addition of Mg2+ effectively increased the luminescence intensity of 0.4 mol% Dy 2 O 3 -doped glass-ceramics. Since Mg2+ has a smaller ionic radius, it has a larger Coulomb potential and is more attractive to O2−, which makes the three-dimensional skeleton of BO 6 tilt, and the symmetry of the structure deteriorates, resulting in enhanced luminescence. Comparison of 0.4 mol%Dy 2 O 3 -doped glass-ceramic and 8 mol%MgF 2 -0.4 mol%Dy 2 O 3 co-doped glass-ceramic, the fluorescence intensity increased by 56.8% at 484 nm and 83.5% at 577 nm, the optical band gap value was reduced from 2.7824 eV to 2.4341 eV. The findings suggest that Dy3+-doped glass-ceramics containing Ca 2 Ti 2 O 6 crystal phase will be used in white light-emitting diodes (W-LEDs). • The Dy3+ doped glass ceramic containing Ca 2 Ti 2 O 6 was synthesized. • The transmittance of glass ceramic can reach 76% in the visible region. • The optimal doped concentration of Dy 2 O 3 is 0.4 mol%. • The addition of Mg2+ results in enhanced luminescence intensity and reduced optical band gap. [ABSTRACT FROM AUTHOR]

• Transparent glass-ceramic containing Ca 2 Ti 2 O 6 crystal phase was prepared. • The luminous intensity of Sm3+was increased by about 49% after introducing 4% Li+. • The color purity of 4%Li+−0.5%Sm3+ co-doped glass-ceramic can reach 95.4%. The Sm3+ doped transparent glass-ceramics were prepared by the melt crystallization method. Using the device of X-ray diffraction (XRD) can confirm Ca 2 Ti 2 O 6 nanocrystals were formed among the precursor glass matrix. Under the optimum heat treatment condition (680 °C/90 min), the average grain size in the glass-ceramic is about 103 nm, and the light transmittance in the visible region can reach 78%. Under 402 nm excitation, the emission spectra show strong emission peaks at 564 nm, 600 nm and 647 nm, corresponding to the 4G 5/2 →6H J (J = 5/2, 7/2, 9/2) characteristic transitions of Sm3+. The optimal doping concentration of Sm3+ is 0.5%, and the concentration quenching caused by exchange interaction will occur if it exceeds this value. The introduction of Li+ into glass-ceramics will not change the crystal phase and can enhance the luminescent intensity. The chromaticity coordinates of 4%Li+-0.5%Sm3+ co-doped glass-ceramic are located in orange region (0.5506, 0.4456), and the color purity can reach 95.4%. The results show that the glass-ceramics have potential applications in solid-state color rendering. [ABSTRACT FROM AUTHOR]

• Dy3+-Eu3+ co-doped glass-ceramics containing ZnMoO 4 was prepared. • The existence of the energy transfer from Dy3+ to Eu3+ was certified. • Warm white light were achieved by adjusting the doped concentration. Dy3+-Eu3+ co-doped glass-ceramics (GCs) containing ZnMoO 4 were successfully prepared. The temperature range of heat treatment was preliminarily determined by differential scanning calorimeter (DSC) and thermogravimetry (TG). The crystalline phase was determined by X-ray diffraction (XRD), the structural feature was analyzed on the basis of Rietveld refinement, the morphology was observed by scanning electron microscopy (SEM), the absorption coefficients were calculated by light transmission curves. Combined with the above analysis, the optimal heat treatment condition was discussed. Through the fluorescence spectra and decay curve, there existed an energy transfer between Dy3+ and Eu3+, and the energy transfer efficiency from Dy3+ to Eu3+ increased with the increase of Eu3+ concentration. By calculating the critical distance and linearly fitting the data, it could be concluded that the mechanism of energy transfer was dipole-dipole interaction. With the changed of Dy3+-Eu3+ doped concentration, the color coordinates of these samples can be tuned in the white light region, and the 0.4% Dy3+-0.7% Eu3+ co-doped glass-ceramics obtained warm white light emission with low correlated color temperature (CCT). These results clearly showed that Dy3+-Eu3+ co-doped GCs containing ZnMoO 4 could be used as a potential candidate material in the field of white light-emitting diodes (w-LEDs). [ABSTRACT FROM AUTHOR]

Dy3+ doped ZnMoO 4 glass-ceramics was prepared by traditional melt crystallization method. The crystalline phase, microscopic morphology, transmittance, the optimal heat treatment condition and luminescence properties of the samples were discussed. The emission peaks are located at 482 nm, 574 nm and 663 nm due to 4F 9/2 →6H 15/2 , 4F 9/2 →6H 13/2 and 4F 9/2 →6H 11/2 transitions of Dy3+ under 387 nm. When the doped concentration of Dy3+ exceeded 0.4%, it was proved that the multi-stage interaction between adjacent ions causes concentration quenching by calculating the critical distance between Dy3+. The chromaticity coordinate (CIE) showed the luminescence color of the samples in the white light region, indicating that Dy3+ doped glass-ceramics containing ZnMoO 4 were expected to be applied in white-light emitting diode (w-LED). [ABSTRACT FROM AUTHOR]

Nd:YAG transparent ceramics were prepared by solid-state reaction and vacuum sintering. The structure of ceramic samples at various sintering temperatures was characterized and analyzed by X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT-IR) and Raman spectroscopy (Raman). The samples were sintered from 1500 °C to 1750 °C for 4 h to study their sintering behavior by scanning electron microscope (SEM). At the same time, the luminescence properties of ceramic samples sintered at 1750 °C for various times were analyzed by the photoluminescence spectra (PL). The results indicated that the relative density and the grain size increased with the increase of sintering temperature and time. The fluorescence intensity increased with the decrease of defect of ceramic samples. [ABSTRACT FROM AUTHOR]

Sm3+ doped precursor glass (PG) was obtained successfully via melt-quenching method and glass ceramic (GC) was precipitated via subsequent heat treatment. Combining the X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses, the optimum heat treatment condition is determined is 635 °C/3 h. The FTIR spectra of the precursor glass and glass ceramic indicate that the enhancement of the luminescent intensity of glass ceramics is related to the MoO 4 2− group appearance. From the transmittance curve of the glass ceramic presents its transmittance can reach 78% in the visible region. The emission spectra indicate the optimum doped concentration of Sm 2 O 3 is 0.3 mol%. Concentration quenching caused by dipole-dipole interaction will occur when Sm 2 O 3 is greater than 0.3 mol%. The calculation results of chromaticity coordinates (CIE) indicates that Sm3+ doped glass ceramic containing SrMoO 4 crystallite may be promising as reddish orange emitting materials. • Sm3+ doped glass ceramic containing SrMoO 4 is synthesized. • The critical distance between Sm3+ is 3.031 nm. • The luminescence properties of Sm3+ doped GC is stronger than PG. [ABSTRACT FROM AUTHOR]

A series of Tm3+ mono-doped and Tm3+-Eu3+ co-doped transparent glass-ceramics (GCs) containing NaY(MoO 4) 2 crystal phase was synthesized by melt quenching and glass crystallization. The optimal heat treatment condition, crystal structure, microscopic morphology, transmittance, luminescent properties and energy transfer of samples were studied using DSC, XRD, SEM, spectrophotometer and fluorescence spectrometer, respectively. When the Tm3+ mono-doped concentration is 0.4%, the emission intensity is the strongest at 456 ​nm due to 1D 2 →3F 4 transition of Tm3+. Energy transfer from Tm3+ to Eu3+ is observed by fluorescence spectra of Tm3+-Eu3+ co-doped GCs, and the optimal doping concentrations of Tm3+ and Eu3+ are 0.4% and 1.3%, respectively. In addition, the Tm3+-Eu3+ co-doped GCs can achieve tunable emission from blue to purple by adjusting the doping concentration of Eu3+. These results indicate that Tm3+ mono-doped and Tm3+-Eu3+ co-doped GCs have potential applications in the field of color display. A series of Tm3+ mono-doped and Tm3+-Eu3+ co-doped transparent glass-ceramics was synthesized. The energy transfer mechanism from Tm3+ to Eu3+ is dipole-quadrupole interaction. With the increase of Eu3+ concentration, the chromaticity coordinates are tuned from the blue region to the purple region. The results show that this glass-ceramics have potential application in color display. Image 1 • The Tm3+ mono-doped and Tm3+-Eu3+ co-doped glass-ceramics are prepared. • The optimum concentrations of Tm3+ and Eu3+ are 0.4% and 1.3%, respectively. • The energy transfer mechanism from Tm3+ to Eu3+ is the dipole-quadrupole interaction. [ABSTRACT FROM AUTHOR]

In this paper, Dy3+ doped SrCO 3 –WO 3 –SiO 2 glass ceramics are successfully prepared by melt-quenching method. The microscopic morphology, structure and luminescence properties of Dy3+ doped glass ceramics are investigated through XRD, DSC, SEM, photoluminescence spectra and decay curves etc. It can be determined that the crystalline phase is SrWO 4 after comparing with PDF normal card by XRD. Also, combining with the transmission curves, the optimum heat treatment temperature and time are 740 °C/1.5 h. In the emission spectrum, there are three obvious emission peaks at 484 nm, 575 nm and 665 nm, respectively. The optimum concentration of Dy3+ is found to be 1.6 mol, and electric multipole interaction is the main reason for the concentration quenching. The maximum fluorescence lifetime is 796.5 μs. • Dy 2 O 3 doped SrCO 3 –WO 3 –SiO 2 glass ceramics are synthesized. • The optimum concentration of Dy3+ is found to be 1.6 mol. • The reason of concentration quenching is dipole-dipole interaction. • The maximum fluorescence lifetime is 796.5 μs. [ABSTRACT FROM AUTHOR]

Tb3+ doped glass ceramics containing SrWO 4 crystals are prepared by melting crystallization method and their luminescence properties are studied. It is determined by DSC that the heat treatment temperature is 730℃ and the time is 2h. Through the XRD of the glass ceramics, it can determine the crystalize phase is SrWO 4 after comparing with PDF normal card. In the emission spectrum of the Tb3+ doped SrWO 4 glass ceramics samples, there are two obvious emission peaks at 490nm and 544nm corresponding to the transitions of 5D 4 →7F 6 and 5D 4 →7F 5 of Tb3+. Based on the fluorescence spectrum, it can be determined that the optimum concentration of Tb 4 O 7 is 1.0 mol, and the fluorescence lifetime is 2.16 ms. [ABSTRACT FROM AUTHOR]

The Na 2 O-Y 2 O 3 -SiO 2 glass with Tb3+ doped and Sm3+/Tb3+ co-doped was prepared by the melt-quenching, the glass ceramics containing Na 9 YSi 6 O 18 crystal phase were prepared by two-step heat treatment. The structure, morphology, luminescence properties and fluorescence lifetimes were investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), transmittance, photoluminescence spectra (PL), respectively. The research indicates that the nuclear temperature of glass ceramics is 550 °C and the time for 1 h, the optimum crystalline temperature is 620 °C, and the optimum crystalline time is 40 min. Moreover, the effect of Tb 2 O 3 concentration on the luminescence properties of the glass ceramics were discussed. When the concentration of Tb 2 O 3 was 0.5 mol%, the brightest green light was obtained at 547 nm (5D 4 →7F 5). Meanwhile, the energy transfer process between Tb3+ and Sm3+was discussed in detail. Under the excitation of 376 nm, the white light can be obtained by adjusting the concentration ratio of Tb3+ and Sm3+. These results indicate that Sm3+/Tb3+ co-doped glass ceramics play an important role in the field of white light-emitting diodes (w-LEDs). • Sm3+/Tb3+ co-doped glass ceramics containing Na 9 YSi 6 O 18 was prepared. • The white light can be obtained by adjusting the concentration ratio of Tb3+/Sm3+. • The energy transfer from Tb3+ to Sm3+ was confirmed. [ABSTRACT FROM AUTHOR]