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The preparation and luminescence of Sm2O3 doped glass ceramics containing Na3Y(PO4)2
Optik - International Journal for Light and Electron Optics 203 (2020) 163934
Contents lists available at ScienceDirect
Optik journal homepage: www.elsevier.com/locate/ijleo
Short note
The preparation and luminescence of Sm2O3 doped glass ceramics containing Na3Y(PO4)2
T
Zhaohua Guo, Jing Shao*, Hongbo Zhang*, Liying Wang School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun, 130022, China
A R T IC LE I N F O
ABS TRA CT
Keywords: Na3Y(PO4)2 Sm2O3 doped Glass ceramics Luminescence
Sm2O3 doped transparent glass ceramics containing Na3Y(PO4)2 crystal phase were synthesized by melting crystallization method. The structure and morphology of the glass ceramics were characterized with X-ray diffraction (XRD) and scanning electron microscopy (SEM). The heat treatment condition of Sm2O3 doped Na3Y(PO4)2 crystal phase glass was 660°C/2h. The glass ceramics with Sm2O3 doped Na3Y(PO4)2 phase are excited by 403nm, and there are emission peaks at 564nm, 600nm and 648nm, respectively. The emission peak intensity of 600nm is the largest, which produces orange light, corresponding to the 6G5/2→4H7/2 transition of Sm3+. Excitation and emission spectra show that the fluorescence intensity was the highest when the concentration of Sm2O3 was 0.6mol%, and the fluorescence lifetime was 2.9377ms.
1. Introduction Nowadays, white light-emitting diode (w-LED), as a new generation of solid-state light source, has been concerned for its high brightness, high reliability, and low energy consumption [1–4]. Rare earth doped phosphors play a significant role in the manufacture of w-LED. The most common method is combining Y3Al5O12:Ce3+ (YAG:Ce) yellow phosphor with a blue LED chip to obtain a w-LED. However, due to the lack of red light emission, this method has a poor color rendering rate (CRI≈70-80) and a high correlated color temperature (CCT≈7750 K) [5]. Moreover, the fluorescent powder has some shortcomings such as low luminescence efficiency, poor stability and large light decay, so it is necessary to find a new luminescent material. The glass ceramic is a good substitute. Glass ceramic has the advantages of simple preparation process, good thermal stability, chemical stability, and good optical properties [6]. In rare earth ions, Sm3+ can produce orange-red light (597−622 nm). For example, Hong Li et al. [7] synthesized Sm3+ doped SrO-Al2O3-SiO2 glass ceramics. Under blue light (475 nm) excitation, it emits green, orange and red light. S.R Munishwar et al. [8] prepared Sm3+ doped sodium boron silicate glass and glass ceramics The glass samples were excited with 402 nm as the excitation wavelength. Due to the transitions of 4G5/2→6H5/2,4G5/2→6H7/2 and 4G5/2→6H9/2, the luminescence spectra show three bands at 562 nm, 601 nm and 647 nm. Weihuan Zhang et al. [9] synthesized Sm3+ doped BaGdF5 transparent glass ceramics. At 403 nm excitation, Sm3+ has a strong emission in glass ceramics, which may be due to the combination of Sm3+ and BaGdF5 with lower phonons, and its chromaticity coordinates are located in the red-orange region. Aleksandra Matraszek et al. [10] prepared Na3Y(PO4)2 phosphors by hydrothermal synthesis in 2014. The quantitative composition of the sample was determined by inductively coupled plasma optical emission spectroscopy (ICP-OES, Varian Vista-MPX) Na:Y:P = 3:1:2 and the XRD pattern of Na3Y(PO4)2 was obtained. The lattice constant of the Na3Y(PO4)2 unit cell was refined by
⁎
Corresponding authors. E-mail addresses: [email protected] (J. Shao), [email protected] (H. Zhang).
https://doi.org/10.1016/j.ijleo.2019.163934 Received 28 September 2019; Accepted 29 November 2019 0030-4026/ © 2019 Elsevier GmbH. All rights reserved.
Optik - International Journal for Light and Electron Optics 203 (2020) 163934
Z. Guo, et al.
Checkcell software [11], and it was found that a = 13.94 Å, b = 5.292 Å, and c = 18.33 Å. Phosphate has the advantages of low synthesis temperature, high stability and low cost. In this work, Sm2O3 doped with transparent glass ceramic containing Na3Y(PO4)2 crystal phase was synthesized. The effect of heat treatment conditions on the crystal phase was analyzed and its luminescence properties were studied. 2. Experimental The composition of the glass sample is 27Na2CO3-2Y2O3-3P2O5-39SiO2-28H2BO3-1Sb2O3-xSm2O3(x = 0, 0.2, 0.4, 0.6, 0.8, 1.0 mol%), weighing about 20 g of raw materials, and evenly mixing it into a crucible. The crucible was placed in the KSX2 energy-saving rapid heating furnace and kept at 1100 ℃ for 1 h, and then heated to 1400℃ for 90 min. The glass melt is poured into a preheated copper plate, pressed and formed, and rapidly transferred to 450 °C muffle furnace for annealing for 2 h, and naturally cooled to room temperature to obtain precursor glass marked as PG. The glass ceramic was obtained after heat treatment of the precursor glass designated as GC. Among them, Na2CO3, Y2O3 and P2O5 are the main components of the crystal phase. P2O5 also acts as a nucleating agent for forming the crystal phase, which can reduce the activation energy of nucleation, SiO2 is used to form the glass network structure, H2BO3 is a flux to make the sample fully mixed. Sb2O3 is a clarifying agent that reduces bubbles formed in the glass, the doping ratio of Sm2O3 is external. The powder was tested by X-ray diffractometer (Rigaku 2500 PC, Japan) to determine the crystal phase contained in the glass matrix, the source of excitation is Cu Kα,and the range of transformation of 2θ is 10-60°. Optical transmittance of glass ceramics was measured by UV-VIS spectrophotometer (SHIMADZU, uvmini-1240). The morphology and particle size of the samples were measured using a SPI3800 N scanning electron microscope manufactured by SII Corporation of Japan. Photoluminescence (PL) excitation and emission spectra were measured on a Sunlite EX OPO manufactured by American Continuum, with a measurement range of 200−800 nm. 3. Results and discussion 3.1. Determination of heat treatment conditions Fig. 1(a) is the DSC curve of the PG. It can be seen that the crystallization starting temperature Tx is about 645 °C and the crystallization peak temperature Tp is 670 °C. The crystallization temperature can be initially determined to be between 640 °C and
Fig. 1. (a) DSC curve of PG, (b) XRD patterns of Sm2O3 doped GC, (c) SEM photo of GC, (d) Transmission curves of PG and GCs. 2
Optik - International Journal for Light and Electron Optics 203 (2020) 163934
Z. Guo, et al.
Fig. 2. a)Excitation spectra, (b)Emission spectra, (c)The decay curves, (d) Chromaticity coordinates.
680 °C. Fig. 1(b) is the XRD patterns of Sm2O3 doped PG heat treated at 640 °C, 650 °C, 660 °C, 670 °C, 680 °C for 1 h. As the heat treatment time increases, the intensity of the diffraction peaks increase. Comparing with the XRD pattern of Na3Y(PO4)2 synthesized by Aleksandra Matraszek et al. [10], it was confirmed that Na3Y(PO4)2 crystal was precipitated. The SEM image of the doped Sm2O3 containing Na3Y(PO4)2 crystal phase glass ceramics at 660 °C/2 h, as shown in Fig. 1(c). The SEM photo shows that the particle size is uniform and evenly distributed. Fig. 1(d) is the light transmittance curves of PG and GC. There is an absorption peak at 403 nm, which corresponds to the transition of 6H5/2→4P3/2 of Sm3+. The light transmittance of PG reaches 85 %. When heat treatment is 660 °C for 2 h, the light transmittance of GC also reaches 75 % in the visible light range. Combined with DSC, XRD, SEM and light transmittance curves, the heat treatment condition of Sm3+ doped glass ceramics containing Na3Y(PO4)2 crystal phase is 660 °C/2 h. 3.2. Luminescence properties Fig. 2(a) shows the excitation spectra of glass ceramics containing Na3Y(PO4)2 crystal phase doped with Sm2O3. When the monitoring wavelength is 600 nm, it can be observed that characteristic peaks exist at 317 nm, 345 nm, 362 nm, 374 nm, 403 nm,417 nm, and 473 nm, due to Sm3+ from 6H5/2 to 4G2/9, 4K17/2, 4D3/2, 6D1/2, 4P3/2, 4M19/2,4M15/2 and 4M17/2 transitions, respectively. Among them, the Sm3+ transition of 6H5/2→4P3/2 at 403 nm is dominant, and the fluorescence intensity is the largest. Fig. 2(b) is the emission spectra at 403 nm. There are emission peaks at 564 nm, 600 nm and 648 nm, corresponding to the Sm3+ transitions of 4G5/2→6H5/2, 4G5/2→6H7/2, 4G5/2→6H9/2 [12]. In the emission spectra, when the doping concentration of Sm2O3 is 0.6 mol%, the fluorescence intensity reaches its maximum. Fluorescence intensity increases with the increase of Sm2O3 concentration, while the doping concentration of Sm2O3 is more than 0.6 mol%, the fluorescence intensity is attenuated as the concentration increases, and concentration quenching occurs. Because of the concentration of Sm3+ increases, the distance between adjacent Sm3+ also decreases. Thus, the interaction between the Sm3+-Sm3+ is enhanced, and the transfer of this enhanced non-radiative energy between Sm3+ can occur through electrical multipole interactions or exchange interactions. In order to determine the energy transfer mechanism of different concentrations of Sm2O3 doped glass ceramics, it is necessary to calculate the critical distance (Rc) between Sm3+. The critical distance Rc is calculated by the following formula [13]: 1/3
3V ⎞ Rc = 2 ⎛ 4 πX cN ⎠ ⎝ ⎜
⎟
(1) 3
Optik - International Journal for Light and Electron Optics 203 (2020) 163934
Z. Guo, et al.
Table 1 Fluorescence lifetime of Sm2O3 doped GC with different concentrations. Sm2O3 (mol%)
τ(ms)
R2
0.2 0.4 0.6 0.8 1.0
2.2948 2.8871 2.9377 2.5940 2.4294
0.9959 0.9978 0.9984 0.9984 0.9979
In the formula, V corresponds to the volume of the unit cell, Xc represents the critical concentration of the ion dopant, and N is the number of host cations in the unit cell. For Na3Y(PO4)2 crystal, the critical distance (Rc) of Sm3+ is 37.75 Å. Rc is greater than 5 Å, indicating that multipole interaction dominates, which is the main cause of concentration quenching. Fig. 2(c) shows that fluorescence decay curves at excitation wavelength λex=403nm and monitoring wavelength λem=600nm.The decay curve is fitted by a single exponential formula:
t I(t) = I0 exp ⎛− ⎞ ⎝ τ⎠
(2)
Where I(t) and I0 are the emission intensities of the Sm2O3 at time t and 0, respectively, and τ is the fluorescence lifetime. Table 1 lists the fluorescence lifetime of glass ceramics doped with different concentrations of Sm2O3. When the Sm2O3 doping concentration 0.6 mol%, the fluorescence lifetime reaches the maximum, t = 2.9377 ms, and the linear fit also reaches the maximum R2 = 0.9984. When the doping concentration of Sm2O3 is greater than 0.6 mol%, the fluorescence lifetime decreased from 2.9377 ms to 2.4294 ms, indicating that the quenching phenomenon of concentration is serious. Fig. 2(d) shows the chromaticity coordinates of different concentrations of Sm2O3 doped GC at 403 nm. As can be seen from the inset of Fig. 2(d), the position of the chromaticity coordinates changes from (0.5075, 0.4779) to (0.5318, 0.4602). The chromaticity coordinates indicate that Sm2O3 doped GC containing Na3Y(PO4)2 crystal phase can produce orange light, which has potential applications in white light-emitting diodes (w-LED). 4. Conclusions GCs with different concentrations of Sm2O3 doped with Na3Y(PO4)2 phase were successfully prepared by melting-crystallization method. By means of XRD, SEM and transmittance curves, the heat treatment condition of glass ceramics was determined to be 660℃/2 h.At the excitation wavelength of 403 nm, it can be observed that Sm2O3 doped with the Na3Y(PO4)2 crystal phase have a maximum fluorescence intensity at 600 nm, corresponding to the 6G5/2→4H7/2 transition of Sm3+. When the doping concentration of Sm2O3 is 0.6 mol%, the fluorescence intensity reaches the maximum, and the fluorescence lifetime is 2.9377 ms. The above results confirm that Sm2O3 doped GC containing Na3Y(PO4)2 crystal phase is a promising orange light-emitting material, which have potential applications in white light-emitting diodes (w-LEDs). Acknowledgment This work was supported by the Project of Jilin Province Science and Technology Department (20190802014ZG). References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]
M. Xin, D. Tu, H.M. Zhu, W.Q. Luo, Z.G. Liu, P. Huang, R.F. Li, Y.G. Caob, X.Y. Chen, Chem. C3 (2015) 7286–7293. W.J. Ding, J. Wang, Z.M. Liu, M. Zhang, Q. Su, J.K. Tang, J. Electrochem. Soc. 155 (2008) J122–J127. J. Lin, Y.H. Hu, L. Chen, Z.H. Wang, S.A. Zhang, J. Mater. Chem. 22 (2012) 19094–19104. K. Munirathnam, P.C. Nagajyothi, D. Prakashbabu, B.D.P. Raju, J. Shim, Ceram. Int. 45 (2019) 686–694. X.J. Zhang, J. Wang, L. Huang, F.J. Pan, Y. Chen, B.F. Lei, M.Y. Peng, M.M. Wu, ACS Appl. Mater. Interfaces 7 (2015) 10044–10054. Y.H. Xia, X.Y. Zou, H.B. Zhang, M.J. Zhao, S. Meng, C.H. Su, J. Shao, J. Non. Solids 774 (2018) 540–546. H. Li, L.W. Liu, X.Z. Tang, Q. Wang, P. Wang, J. Wuhan, Univ. Technol. 43 (2017) 548–555. S.R. Munishwar, K. Roy, R.S. Gedam, Mater. Res. Express 4 (2017) 1–18. W.H. Zhang, Y.P. Zhang, S. Ouyang, Z.X. Zhang, H.P. Xia, Mater. Lett. 160 (2015) 459–462. A. Matraszek, I. Szczygieł, B. Szczygieł, J. Alloys. Compd. 612 (2014) 411–417. P. Godlewska, A. Matraszek, L. Macalik, K. Hermanowicz, J. Alloys. Compd. 628 (2015) 199–207. T. Suhasini, J.S. Kumar, T. Sasikala, K.W. Jang, H.S. Lee, M. Jayasimhadri, et al., Opt. Mater. (Amst) 31 (2009) 1167–1172. C. Chen, M.J. Zhao, H.B. Zhang, X. Chen, Q.L. Wei, X.Y. Zou, Mater. Res. Bull. 104 (2018) 72–76.
4
Contents lists available at ScienceDirect
Optik journal homepage: www.elsevier.com/locate/ijleo
Short note
The preparation and luminescence of Sm2O3 doped glass ceramics containing Na3Y(PO4)2
T
Zhaohua Guo, Jing Shao*, Hongbo Zhang*, Liying Wang School of Chemistry and Environmental Engineering, Changchun University of Science and Technology, Changchun, 130022, China
A R T IC LE I N F O
ABS TRA CT
Keywords: Na3Y(PO4)2 Sm2O3 doped Glass ceramics Luminescence
Sm2O3 doped transparent glass ceramics containing Na3Y(PO4)2 crystal phase were synthesized by melting crystallization method. The structure and morphology of the glass ceramics were characterized with X-ray diffraction (XRD) and scanning electron microscopy (SEM). The heat treatment condition of Sm2O3 doped Na3Y(PO4)2 crystal phase glass was 660°C/2h. The glass ceramics with Sm2O3 doped Na3Y(PO4)2 phase are excited by 403nm, and there are emission peaks at 564nm, 600nm and 648nm, respectively. The emission peak intensity of 600nm is the largest, which produces orange light, corresponding to the 6G5/2→4H7/2 transition of Sm3+. Excitation and emission spectra show that the fluorescence intensity was the highest when the concentration of Sm2O3 was 0.6mol%, and the fluorescence lifetime was 2.9377ms.
1. Introduction Nowadays, white light-emitting diode (w-LED), as a new generation of solid-state light source, has been concerned for its high brightness, high reliability, and low energy consumption [1–4]. Rare earth doped phosphors play a significant role in the manufacture of w-LED. The most common method is combining Y3Al5O12:Ce3+ (YAG:Ce) yellow phosphor with a blue LED chip to obtain a w-LED. However, due to the lack of red light emission, this method has a poor color rendering rate (CRI≈70-80) and a high correlated color temperature (CCT≈7750 K) [5]. Moreover, the fluorescent powder has some shortcomings such as low luminescence efficiency, poor stability and large light decay, so it is necessary to find a new luminescent material. The glass ceramic is a good substitute. Glass ceramic has the advantages of simple preparation process, good thermal stability, chemical stability, and good optical properties [6]. In rare earth ions, Sm3+ can produce orange-red light (597−622 nm). For example, Hong Li et al. [7] synthesized Sm3+ doped SrO-Al2O3-SiO2 glass ceramics. Under blue light (475 nm) excitation, it emits green, orange and red light. S.R Munishwar et al. [8] prepared Sm3+ doped sodium boron silicate glass and glass ceramics The glass samples were excited with 402 nm as the excitation wavelength. Due to the transitions of 4G5/2→6H5/2,4G5/2→6H7/2 and 4G5/2→6H9/2, the luminescence spectra show three bands at 562 nm, 601 nm and 647 nm. Weihuan Zhang et al. [9] synthesized Sm3+ doped BaGdF5 transparent glass ceramics. At 403 nm excitation, Sm3+ has a strong emission in glass ceramics, which may be due to the combination of Sm3+ and BaGdF5 with lower phonons, and its chromaticity coordinates are located in the red-orange region. Aleksandra Matraszek et al. [10] prepared Na3Y(PO4)2 phosphors by hydrothermal synthesis in 2014. The quantitative composition of the sample was determined by inductively coupled plasma optical emission spectroscopy (ICP-OES, Varian Vista-MPX) Na:Y:P = 3:1:2 and the XRD pattern of Na3Y(PO4)2 was obtained. The lattice constant of the Na3Y(PO4)2 unit cell was refined by
⁎
Corresponding authors. E-mail addresses: [email protected] (J. Shao), [email protected] (H. Zhang).
https://doi.org/10.1016/j.ijleo.2019.163934 Received 28 September 2019; Accepted 29 November 2019 0030-4026/ © 2019 Elsevier GmbH. All rights reserved.
Optik - International Journal for Light and Electron Optics 203 (2020) 163934
Z. Guo, et al.
Checkcell software [11], and it was found that a = 13.94 Å, b = 5.292 Å, and c = 18.33 Å. Phosphate has the advantages of low synthesis temperature, high stability and low cost. In this work, Sm2O3 doped with transparent glass ceramic containing Na3Y(PO4)2 crystal phase was synthesized. The effect of heat treatment conditions on the crystal phase was analyzed and its luminescence properties were studied. 2. Experimental The composition of the glass sample is 27Na2CO3-2Y2O3-3P2O5-39SiO2-28H2BO3-1Sb2O3-xSm2O3(x = 0, 0.2, 0.4, 0.6, 0.8, 1.0 mol%), weighing about 20 g of raw materials, and evenly mixing it into a crucible. The crucible was placed in the KSX2 energy-saving rapid heating furnace and kept at 1100 ℃ for 1 h, and then heated to 1400℃ for 90 min. The glass melt is poured into a preheated copper plate, pressed and formed, and rapidly transferred to 450 °C muffle furnace for annealing for 2 h, and naturally cooled to room temperature to obtain precursor glass marked as PG. The glass ceramic was obtained after heat treatment of the precursor glass designated as GC. Among them, Na2CO3, Y2O3 and P2O5 are the main components of the crystal phase. P2O5 also acts as a nucleating agent for forming the crystal phase, which can reduce the activation energy of nucleation, SiO2 is used to form the glass network structure, H2BO3 is a flux to make the sample fully mixed. Sb2O3 is a clarifying agent that reduces bubbles formed in the glass, the doping ratio of Sm2O3 is external. The powder was tested by X-ray diffractometer (Rigaku 2500 PC, Japan) to determine the crystal phase contained in the glass matrix, the source of excitation is Cu Kα,and the range of transformation of 2θ is 10-60°. Optical transmittance of glass ceramics was measured by UV-VIS spectrophotometer (SHIMADZU, uvmini-1240). The morphology and particle size of the samples were measured using a SPI3800 N scanning electron microscope manufactured by SII Corporation of Japan. Photoluminescence (PL) excitation and emission spectra were measured on a Sunlite EX OPO manufactured by American Continuum, with a measurement range of 200−800 nm. 3. Results and discussion 3.1. Determination of heat treatment conditions Fig. 1(a) is the DSC curve of the PG. It can be seen that the crystallization starting temperature Tx is about 645 °C and the crystallization peak temperature Tp is 670 °C. The crystallization temperature can be initially determined to be between 640 °C and
Fig. 1. (a) DSC curve of PG, (b) XRD patterns of Sm2O3 doped GC, (c) SEM photo of GC, (d) Transmission curves of PG and GCs. 2
Optik - International Journal for Light and Electron Optics 203 (2020) 163934
Z. Guo, et al.
Fig. 2. a)Excitation spectra, (b)Emission spectra, (c)The decay curves, (d) Chromaticity coordinates.
680 °C. Fig. 1(b) is the XRD patterns of Sm2O3 doped PG heat treated at 640 °C, 650 °C, 660 °C, 670 °C, 680 °C for 1 h. As the heat treatment time increases, the intensity of the diffraction peaks increase. Comparing with the XRD pattern of Na3Y(PO4)2 synthesized by Aleksandra Matraszek et al. [10], it was confirmed that Na3Y(PO4)2 crystal was precipitated. The SEM image of the doped Sm2O3 containing Na3Y(PO4)2 crystal phase glass ceramics at 660 °C/2 h, as shown in Fig. 1(c). The SEM photo shows that the particle size is uniform and evenly distributed. Fig. 1(d) is the light transmittance curves of PG and GC. There is an absorption peak at 403 nm, which corresponds to the transition of 6H5/2→4P3/2 of Sm3+. The light transmittance of PG reaches 85 %. When heat treatment is 660 °C for 2 h, the light transmittance of GC also reaches 75 % in the visible light range. Combined with DSC, XRD, SEM and light transmittance curves, the heat treatment condition of Sm3+ doped glass ceramics containing Na3Y(PO4)2 crystal phase is 660 °C/2 h. 3.2. Luminescence properties Fig. 2(a) shows the excitation spectra of glass ceramics containing Na3Y(PO4)2 crystal phase doped with Sm2O3. When the monitoring wavelength is 600 nm, it can be observed that characteristic peaks exist at 317 nm, 345 nm, 362 nm, 374 nm, 403 nm,417 nm, and 473 nm, due to Sm3+ from 6H5/2 to 4G2/9, 4K17/2, 4D3/2, 6D1/2, 4P3/2, 4M19/2,4M15/2 and 4M17/2 transitions, respectively. Among them, the Sm3+ transition of 6H5/2→4P3/2 at 403 nm is dominant, and the fluorescence intensity is the largest. Fig. 2(b) is the emission spectra at 403 nm. There are emission peaks at 564 nm, 600 nm and 648 nm, corresponding to the Sm3+ transitions of 4G5/2→6H5/2, 4G5/2→6H7/2, 4G5/2→6H9/2 [12]. In the emission spectra, when the doping concentration of Sm2O3 is 0.6 mol%, the fluorescence intensity reaches its maximum. Fluorescence intensity increases with the increase of Sm2O3 concentration, while the doping concentration of Sm2O3 is more than 0.6 mol%, the fluorescence intensity is attenuated as the concentration increases, and concentration quenching occurs. Because of the concentration of Sm3+ increases, the distance between adjacent Sm3+ also decreases. Thus, the interaction between the Sm3+-Sm3+ is enhanced, and the transfer of this enhanced non-radiative energy between Sm3+ can occur through electrical multipole interactions or exchange interactions. In order to determine the energy transfer mechanism of different concentrations of Sm2O3 doped glass ceramics, it is necessary to calculate the critical distance (Rc) between Sm3+. The critical distance Rc is calculated by the following formula [13]: 1/3
3V ⎞ Rc = 2 ⎛ 4 πX cN ⎠ ⎝ ⎜
⎟
(1) 3
Optik - International Journal for Light and Electron Optics 203 (2020) 163934
Z. Guo, et al.
Table 1 Fluorescence lifetime of Sm2O3 doped GC with different concentrations. Sm2O3 (mol%)
τ(ms)
R2
0.2 0.4 0.6 0.8 1.0
2.2948 2.8871 2.9377 2.5940 2.4294
0.9959 0.9978 0.9984 0.9984 0.9979
In the formula, V corresponds to the volume of the unit cell, Xc represents the critical concentration of the ion dopant, and N is the number of host cations in the unit cell. For Na3Y(PO4)2 crystal, the critical distance (Rc) of Sm3+ is 37.75 Å. Rc is greater than 5 Å, indicating that multipole interaction dominates, which is the main cause of concentration quenching. Fig. 2(c) shows that fluorescence decay curves at excitation wavelength λex=403nm and monitoring wavelength λem=600nm.The decay curve is fitted by a single exponential formula:
t I(t) = I0 exp ⎛− ⎞ ⎝ τ⎠
(2)
Where I(t) and I0 are the emission intensities of the Sm2O3 at time t and 0, respectively, and τ is the fluorescence lifetime. Table 1 lists the fluorescence lifetime of glass ceramics doped with different concentrations of Sm2O3. When the Sm2O3 doping concentration 0.6 mol%, the fluorescence lifetime reaches the maximum, t = 2.9377 ms, and the linear fit also reaches the maximum R2 = 0.9984. When the doping concentration of Sm2O3 is greater than 0.6 mol%, the fluorescence lifetime decreased from 2.9377 ms to 2.4294 ms, indicating that the quenching phenomenon of concentration is serious. Fig. 2(d) shows the chromaticity coordinates of different concentrations of Sm2O3 doped GC at 403 nm. As can be seen from the inset of Fig. 2(d), the position of the chromaticity coordinates changes from (0.5075, 0.4779) to (0.5318, 0.4602). The chromaticity coordinates indicate that Sm2O3 doped GC containing Na3Y(PO4)2 crystal phase can produce orange light, which has potential applications in white light-emitting diodes (w-LED). 4. Conclusions GCs with different concentrations of Sm2O3 doped with Na3Y(PO4)2 phase were successfully prepared by melting-crystallization method. By means of XRD, SEM and transmittance curves, the heat treatment condition of glass ceramics was determined to be 660℃/2 h.At the excitation wavelength of 403 nm, it can be observed that Sm2O3 doped with the Na3Y(PO4)2 crystal phase have a maximum fluorescence intensity at 600 nm, corresponding to the 6G5/2→4H7/2 transition of Sm3+. When the doping concentration of Sm2O3 is 0.6 mol%, the fluorescence intensity reaches the maximum, and the fluorescence lifetime is 2.9377 ms. The above results confirm that Sm2O3 doped GC containing Na3Y(PO4)2 crystal phase is a promising orange light-emitting material, which have potential applications in white light-emitting diodes (w-LEDs). Acknowledgment This work was supported by the Project of Jilin Province Science and Technology Department (20190802014ZG). References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13]
M. Xin, D. Tu, H.M. Zhu, W.Q. Luo, Z.G. Liu, P. Huang, R.F. Li, Y.G. Caob, X.Y. Chen, Chem. C3 (2015) 7286–7293. W.J. Ding, J. Wang, Z.M. Liu, M. Zhang, Q. Su, J.K. Tang, J. Electrochem. Soc. 155 (2008) J122–J127. J. Lin, Y.H. Hu, L. Chen, Z.H. Wang, S.A. Zhang, J. Mater. Chem. 22 (2012) 19094–19104. K. Munirathnam, P.C. Nagajyothi, D. Prakashbabu, B.D.P. Raju, J. Shim, Ceram. Int. 45 (2019) 686–694. X.J. Zhang, J. Wang, L. Huang, F.J. Pan, Y. Chen, B.F. Lei, M.Y. Peng, M.M. Wu, ACS Appl. Mater. Interfaces 7 (2015) 10044–10054. Y.H. Xia, X.Y. Zou, H.B. Zhang, M.J. Zhao, S. Meng, C.H. Su, J. Shao, J. Non. Solids 774 (2018) 540–546. H. Li, L.W. Liu, X.Z. Tang, Q. Wang, P. Wang, J. Wuhan, Univ. Technol. 43 (2017) 548–555. S.R. Munishwar, K. Roy, R.S. Gedam, Mater. Res. Express 4 (2017) 1–18. W.H. Zhang, Y.P. Zhang, S. Ouyang, Z.X. Zhang, H.P. Xia, Mater. Lett. 160 (2015) 459–462. A. Matraszek, I. Szczygieł, B. Szczygieł, J. Alloys. Compd. 612 (2014) 411–417. P. Godlewska, A. Matraszek, L. Macalik, K. Hermanowicz, J. Alloys. Compd. 628 (2015) 199–207. T. Suhasini, J.S. Kumar, T. Sasikala, K.W. Jang, H.S. Lee, M. Jayasimhadri, et al., Opt. Mater. (Amst) 31 (2009) 1167–1172. C. Chen, M.J. Zhao, H.B. Zhang, X. Chen, Q.L. Wei, X.Y. Zou, Mater. Res. Bull. 104 (2018) 72–76.
4