Enhanced photoluminescence property of co-doped ZnB2O4: Eu3+, Tb3+ phosphor prepared by a thermal conversion method

Yu-Yan Liang; Li-Jun Qiao; Zhi-Hong Liu

doi:10.1557/jmr.2015.402

Enhanced photoluminescence property of co-doped ZnB2O4: Eu3+, Tb3+ phosphor prepared by a thermal conversion method

Published online by Cambridge University Press: 13 January 2016

Yu-Yan Liang ,

Li-Jun Qiao and

Zhi-Hong Liu

Show author details

Yu-Yan Liang: Affiliation:
Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, Shaanxi, People's Republic of China
Li-Jun Qiao: Affiliation:
Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, Shaanxi, People's Republic of China
Zhi-Hong Liu*: Affiliation:
Key Laboratory for Macromolecular Science of Shaanxi Province, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710062, Shaanxi, People's Republic of China
*: a) Address all correspondence to this author. e-mail: liuzh@snnu.edu.cn

Article contents

Abstract
INTRODUCTION
EXPERIMENTAL
RESULTS AND DISCUSSION
CONCLUSIONS
References

Abstract

The co-doped ZnB2O4:Eu3+, Tb3+ phosphor was prepared by a thermal conversion method using Zn[B3O3(OH)5]·H2O:Eu3+, Tb3+ as the precursor, which was characterized by energy dispersive x-ray spectrometer, x-ray powder diffraction, infrared, scanning electron microscopy, and photoluminescence. The effects of doped concentration, calcining temperature, and calcining time of precursor on the luminescence property of ZnB2O4: Eu3+, Tb3+ phosphor were investigated. The results showed that the ZnB2O4: Eu3+, Tb3+ phosphor with maximum luminescent intensity was obtained by calcining the precursor at 900 °C for 6 h. It is found that the ZnB2O4: Eu3+, Tb3+ phosphor prepared by this method exhibits much stronger emission intensity than that synthesized by conventional high temperature solid-state method. Meanwhile, ZnB2O4: Eu3+, Tb3+ also has stronger emission intensity and higher red to orange ratio than those of ZnB2O4: Eu3+.

Keywords

ZnB2O4 phosphor Eu3+/Tb3+ co-doping precursor a thermal conversion method luminescence property

Information

Type: Articles
Information: Journal of Materials Research , Volume 31 , Issue 2 , 28 January 2016 , pp. 195 - 201

DOI: https://doi.org/10.1557/jmr.2015.402 [Opens in a new window]
Copyright: Copyright © Materials Research Society 2016

I. INTRODUCTION

There are many kinds of zinc borates found in nature as well as synthesized in the laboratory. Some of these borates have useful properties. During the past years, many borates were chosen as host lattices for phosphors because of their large band gap, high thermal stability, high luminescence efficiency, and low cost.^{Reference Liu, Wang, Wu and Kuang1,Reference Liu, Liang, Kuang, Zhong, Sun and Tao2}

In recent years, zinc borates began to obtain some attentions being a host for photoluminescence (PL) applications, which were activated by trivalent rare-earth ions. For the preparation of lanthanide doped zinc borates luminescent materials, several methods have been designed, for example, Li et al. prepared Zn(BO₂)₂:Tb³⁺ or Dy³⁺ powder samples by the method of solid phase reaction at high temperature.^{Reference Li, Zhang, Tang, Zhang, Hao, Su and Wang3,Reference Li, Zhang, Tang, Hao, Zhang, Su and Wang4} Zheng et al. prepared Eu³⁺ doped ZnB₂O₄ with co-precipitation method.^{Reference Zheng, Qu, Tian, Rong, Wang, Li, Chen and Ma5} Liu et al. prepared Eu³⁺, Bi³⁺ co-activated ZnB₂O₄ with solid state reactions and found Eu³⁺ in ZnB₂O₄ exhibits a dominant emission peak at 610 nm under the excitation at 393 nm.^{Reference Liu, Lin, Chiu, Yeh, Jang and Liu6} Mu et al. prepared Bi³⁺, Gd³⁺ co-doped ZnB₂O₄ with solid state method.^{Reference Mu, Hu, Chen, Wang, Chen, Wang, Fu and Xu7}

To the best of our knowledge, the luminescence properties of Eu³⁺ and Tb³⁺ co-activated ZnB₂O₄ have not been reported yet. In this paper, we report a novel thermal conversion method for preparation of ZnB₂O₄: Eu³⁺, Tb³⁺ phosphor using Zn[B₃O₃(OH)₅]·H₂O: Eu³⁺, Tb³⁺ as the precursor for the first time. The results show that ZnB₂O₄: Eu³⁺, Tb³⁺ has stronger emission intensity than that prepared by conventional high temperature solid state reaction method. Meanwhile, ZnB₂O₄: Eu³⁺, Tb³⁺ has stronger emission intensity and higher red to orange ratio than ZnB₂O₄: Eu³⁺.

II. EXPERIMENTAL

A. Preparation of Zn[B₃O₃(OH)₅]·H₂O: Eu³⁺, Tb³⁺ precursor

All of the reagents were of analytical grade and used directly without further purification. In a typical synthesis, stoichiometric ZnSO₄·7H₂O, Eu₂O₃, and Tb₄O₇ were dissolved in 80 mL of H₂O, in which Tb³⁺ ion doped concentration was variable from 1 mol% to 15 mol% of total mole numbers for Zn²⁺, Eu³⁺, and Tb³⁺ while the Eu³⁺ doped concentration was fixed 6 mol% of Zn²⁺, Eu³⁺, and Tb³⁺. And then, 80 mL of solution containing 0.01 mol of Na₂B₄O₇·10H₂O and 1 mmol cetyltrimethyl ammonium bromide (CTAB) used as the surfactant was added. After being vigorously stirred for 48 h at room temperature, the obtained precipitate was washed with distilled water and absolute alcohol several times and dried at 50 °C for several hours for further characterization. The possible formation reactions are expressed as follows:

(1)

$${\left[ {{{\rm{B}}_4}{{\rm{O}}_5}{{\left( {{\rm{OH}}} \right)}_4}} \right]^{2 - }} + 2{{\rm{H}}_2}{\rm{O\ }} = = {\rm{\ }}{\left[ {{{\rm{B}}_3}{{\rm{O}}_3}{{\left( {{\rm{OH}}} \right)}_5}} \right]^{2 - }} + {{\rm{H}}_3}{\rm{B}}{{\rm{O}}_3}\quad ,$$

(2)

$${\left[ {{{\rm{B}}_3}{{\rm{O}}_3}{{\left( {{\rm{OH}}} \right)}_5}} \right]^{2 - }} + {\rm{Z}}{{\rm{n}}^{2 + }} + \left( {{\rm{{\rm E}}}{{\rm{u}}^{3 + }},{\rm{T}}{{\rm{b}}^{3 + }}} \right) + {{\rm{{\rm H}}}_2}{\rm{O}} = = {\rm{Zn}}\left[ {{{\rm{B}}_3}{{\rm{O}}_3}{{\left( {{\rm{OH}}} \right)}_5}} \right]\cdot{{\rm{H}}_2}{\rm{O}}:{\rm{{\rm E}}}{{\rm{u}}^{3 + }},{\rm{T}}{{\rm{b}}^{3 + }}\quad .$$

B. Preparation of ZnB₂O₄: Eu³⁺, Tb³⁺ phosphors

The samples named A-700, A-800, and A-900 were prepared by calcining the Zn[B₃O₃(OH)₅]·H₂O: Eu³⁺, Tb³⁺ precursor at 700, 800, and 900 °C for 6 h in air, respectively. The possible thermal conversion reaction is expressed as follows:

(3)

$${\rm{Zn}}\left[ {{{\rm{B}}_3}{{\rm{O}}_3}{{\left( {{\rm{OH}}} \right)}_5}} \right]\cdot{{\rm{H}}_2}{\rm{O}}:{\rm{E}}{{\rm{u}}^{3 + }},{\rm{T}}{{\rm{b}}^{3 + }}\buildrel {700-900\,{\rm{^\circ C}}} \over \longrightarrow {\rm{Zn}}{{\rm{B}}_2}{{\rm{O}}_4}:{\rm{E}}{{\rm{u}}^{3 + }},{\rm{T}}{{\rm{b}}^{3 + }} + 3.5{{\rm{H}}_2}{\rm{O}} + 0.5{{\rm{B}}_2}{{\rm{O}}_3}\quad .$$

For comparison, polycrystalline samples of ZnB₂O₄:Eu³⁺ phosphor and ZnB₂O₄:Eu³⁺, Tb³⁺ (B-900) powder were also synthesized by conventional high temperature solid state reaction. The mixture of all materials for ZnO, H₃BO₃, Eu₂O₃, and Tb₄O₇ in stoichiometric proportion was ground in an agate mortar and then transferred to platinum crucibles, which was heated at 900 °C for 6 h in a furnace under ambient atmosphere, followed by cooling to room temperature. The cooled sample was ground again and washed with distilled water and absolute alcohol several times, and then dried at 50 °C for several hours for further characterization.

The doping amount of Tb³⁺ in ZnB₂O₄:Eu³⁺, Tb³⁺ (A) and ZnB₂O₄: Eu³⁺, Tb³⁺ (B-900) was 3 mol% of Zn²⁺, Eu³⁺, and Tb³⁺, while the Eu³⁺ doped concentration was fixed 6 mol% of Zn²⁺, Eu³⁺, and Tb³⁺. The doping amount of Eu³⁺ in ZnB₂O₄: Eu³⁺ is 6 mol% of Zn²⁺ and Eu³⁺.

C. Characterization

The phase composition, purity, and crystallinity of the samples were characterized by Fourier transform infrared (FT-IR) spectroscopy (recorded over the 400–4000 cm⁻¹ region on a Nicolet NEXUS 670 spectrometer [Nicolet Corporation, Madison, Wisconsin] with KBr pellets at room temperature), X-ray powder diffraction (XRD, Rigaku D/MAX-C, Cu K_α radiation at 40 kV and 40 mA [Rigaku Corporation, Tokyo, Japan]), and energy dispersive x-ray spectrometer (EDS, JEOL-6700F, Hitachi Limited, Tokyo, Japan). The morphologies and sizes of the products were investigated by scanning electron microscopy (SEM, Philips-FEI, Quanta 200, FEI Corporation, Hillsboro, Oregon). The PL spectra were recorded on a molecular fluorescence spectrometer (FL-4600, Hitachi Limited) equipped with a 150 W xenon lamp as the excitation source at room temperature.

III. RESULTS AND DISCUSSION

A. Phase identification and morphology

The EDS patterns of Zn[B₃O₃(OH)₅]·H₂O: Eu³⁺, Tb³⁺, ZnB₂O₄: Eu³⁺, Tb³⁺ (A-900), and ZnB₂O₄: Eu³⁺, Tb³⁺ (B-900) are shown in Fig. 1. The elements of Zn, B, O, Eu, and Tb existed in these samples, and no other elements were found except Au which was from the process of pretreatment. From these results, we can conclude that the Eu³⁺ ions and Tb³⁺ ions doped phosphors were prepared successfully.

FIG. 1.

EDS of samples: (a) Zn[B₃O₃(OH)₅]·H₂O: Eu³⁺, Tb³⁺; (b) ZnB₂O₄: Eu³⁺, Tb³⁺ (A-900); (c) ZnB₂O₄: Eu³⁺, Tb³⁺ (B-900).

Figure 2 shows the XRD patterns of all the synthesized samples. It can be seen that all the diffraction peaks and data in Fig. 2 are in good agreement with those in JCPDS file No.72-1789 for Zn[B₃O₃(OH)₅]·H₂O and JCPDS file No.39-1126 for ZnB₂O₄, respectively. There are no peaks of impurities being observed. From these results, we can conclude that the Eu³⁺ and Tb³⁺ co-doped phosphors were prepared successfully by calcining the precursors, and the doping of Eu³⁺ and Tb³⁺ did not change the structures of the products.

FIG. 2.

XRD patterns of samples: (a) Zn[B₃O₃(OH)₅]·H₂O: Eu³⁺, Tb³⁺; (b) ZnB₂O₄: Eu³⁺, Tb³⁺ (A-900); (c) ZnB₂O₄: Eu³⁺, Tb³⁺ (B-900); (d) ZnB₂O₄: Eu³⁺.

Figure 3 shows the FT-IR spectra of all the synthesized samples. Their absorption bands are assigned referring to literature.^{Reference Li, Xia and Gao8} In Fig. 3(a) for Zn[B₃O₃(OH)₅]·H₂O: Eu³⁺, Tb³⁺, the band at 3200 cm⁻¹ is the stretching of O–H. The band at 2496 cm⁻¹ is attributed to the O–H stretching because of hydrogen bonding. The band at 1625 cm⁻¹ is the H–O–H bending of lattice water. The peaks at 1391, 1263, and 880 cm⁻¹ might be asymmetric and symmetric stretching of B(3)–O, respectively. The peaks at 1175, 1030, and 768 cm⁻¹ are the asymmetric and symmetric stretching of B (4)–O, respectively. The peak at 768 cm⁻¹ is the out-of-plane bending of B (3)–O. The peak at 582 cm⁻¹ is the bending of B (3)–O and B(4)–O. In Figs. 3(b) and 3(c) for samples ZnB₂O₄: Eu³⁺, Tb³⁺ (A-900), and ZnB₂O₄: Eu³⁺, Tb³⁺ (B-900), their FT-IR spectra are almost the same. The very strong bands at 1384 and 930 cm⁻¹ might be asymmetric and symmetric stretching of B (3)–O, respectively. The band at 1092 cm⁻¹ is related to B–O chain stretching. The band at 696 cm⁻¹ is the out-of-plane bending of B (3)–O. The band at 470 cm⁻¹ is attributed to the stretching mode of Zn–O.

FIG. 3.

The FT-IR spectra of samples: (a) Zn[B₃O₃(OH)₅]·H₂O: Eu³⁺, Tb³⁺; (b) ZnB₂O₄: Eu³⁺, Tb³⁺(A-900); (c) ZnB₂O₄: Eu³⁺, Tb³⁺ (B-900).

B. The excitation and emission spectra of ZnB₂O₄: Eu³⁺, Tb³⁺

Figure 4 shows the excitation (insert) and emission spectra of ZnB₂O₄: Eu³⁺, Tb³⁺ phosphor. The broad and strongest excitation band at 243 nm can be attributed to the O²⁻ → Eu³⁺ charge transfer transition, which corresponds to the electronic transitions from the 2p orbital of O²⁻ to the 4f orbital of Eu³⁺. The sharp excitation peaks between 300 and 500 nm are due to the typical f–f transition of Eu³⁺.^{Reference Parchur and Ningthoujam9} Upon excitation samples at 243 nm, the emission spectrum involves the characteristic emission lines originating from ⁵D₀ low energy transfer of Eu³⁺, corresponding to ⁵D₀ → ⁷F₁ (590, 601 nm), ⁵D₀ → ⁷F₂ (611 nm i.e., the strongest emission peak) and ⁵D₀ → ⁷F₄ (691 nm), respectively.^{Reference Parchur and Ningthoujam9} Meanwhile, the emission spectrum also involves the characteristic emission lines of Tb³⁺, corresponding to the ⁵D₄ → ⁷F₄ (585 nm) and ⁵D₄ → ⁷F₃ (621 nm) transitions, respectively.^{Reference Som and Sharma10}

FIG. 4.

The excitation (insert) and emission spectra of ZnB₂O₄: Eu³⁺, Tb³⁺.

The intensity of red emission, centering around 611 nm, is enhanced remarkably, which may be ascribed to the increase of defect concentration. In addition, it also shows that the PL intensity of Eu³⁺(⁵D₀ → ⁷F₂, 611 nm) is higher than that of Tb³⁺(⁵D₄ → ⁷F₅, 585 nm), which may be explained to Tb³⁺ → Eu³⁺ energy transfer, namely Tb³⁺ ions transfer the absorption of energy to Eu³⁺ ions effectively, making the intensity of Eu³⁺ ions enhanced.^{Reference Som and Sharma10}

C. The effect of doped concentration on the PL intensity of ZnB₂O₄: Eu³⁺, Tb³⁺

To understand the effect of doped concentration on the PL intensity of ZnB₂O₄:Eu³⁺, Tb³⁺ phosphor, the emission spectra of the Tb³⁺ and Eu³⁺ co-doped Zn[B₃O₃(OH)₅]·H₂O samples with various Eu³⁺/Tb³⁺ molar ratios were recorded on excitation at 260 nm, as shown in Fig. 5(a). It can be found that the emission intensities increase up to 3 mol% and then decreases. The decrease in the emission intensity occurs as a result of the nonradiative energy transfer between the Tb³⁺ ions due to the electric multiple–multiple interactions, which is distance-dependent according to Dexter's theory,^{Reference Liu, Lin and Lin11} thus the quenching concentration of Tb³⁺ was found to be 3 mol%. So, the PL spectra of ZnB₂O₄: Eu³⁺, Tb³⁺ phosphors with Eu³⁺/Tb³⁺ molar ratios for 6:1, 6:1.5, 6:2, 6:2.5, and 6:3 on excitation at 243 nm were investigated, as shown in Fig. 5(b).

FIG. 5.

(A) The PL spectra of Zn[B₃O₃(OH)₅]·H₂O: 0.06Eu³⁺, yTb³⁺ samples: (a) 2%, (b) 3%, (c) 5%, (d) 10%, (e) 15%; (B) The PL spectra of ZnB₂O₄: 6%Eu³⁺, yTb³⁺ samples: (a) 1%, (b) 1.5%, (c) 2%, (d) 2.5%, (e) 3%.

It can be found from Fig. 5(b) that the emission peak positions of all these samples are almost the same, but the emission intensities are varied. The intensity of red emission centering around 611 nm is enhanced remarkably, and the emission intensities and the red to orange intensity ratio of ⁵D₀ → ⁷F₂ (611 nm)/⁵D₀ → ⁷F₁(590, 601 nm) are enhanced with the increase of Tb³⁺ doped concentrations, which may be explained by energy transfer between Tb³⁺ and Eu³⁺.^{Reference Som and Sharma10} Here, Tb³⁺ acts as a sensitizer and Eu³⁺ as an activator.

So we chose the optimum doping amount of Tb³⁺ was 3 mol%, while the Eu³⁺ doped concentration was fixed 6 mol%.

D. Effect of the calcination temperature on the PL properties of ZnB₂O₄: Eu³⁺, Tb³⁺

Figure 6 shows the XRD patterns of samples prepared by calcining precursor Zn[B₃O₃(OH)₅]·H₂O: Eu³⁺, Tb³⁺ at 700, 800, and 900 °C, respectively. From Fig. 6, it can be seen that the ZnB₂O₄: Eu³⁺, Tb³⁺ phosphors were obtained at 800 °C and 900 °C, and another phosphor ZnB₄O₇: Eu³⁺, Tb³⁺ was obtained at 700 °C. It needs to indicate that the glassy state sample was obtained at 1000 °C.

FIG. 6.

XRD patterns of samples prepared by calcining the precursor at various temperatures:(a) A-700, (b) A-800, (c) A-900.

Figure 7 shows the emission spectra of phosphors named A-700, A-800, and A-900. It can be seen that the ZnB₄O₇: Eu³⁺, Tb³⁺ only has weak emission, but the ZnB₂O₄: Eu³⁺, Tb³⁺ phosphors have strong emission, and the maximum emission intensity is observed at 900 °C, which is in good agreement with the results of the XRD analysis (Fig. 6), as optimum crystallinity is presented at 900 °C.

FIG. 7.

Emission spectra of samples prepared by calcining the precursor at various temperatures:(a) A-700, (b) A-800, (c) A-900.

E. Effect of the calcination time on the PL properties of ZnB₂O₄: Eu³⁺, Tb³⁺

It can be seen from Fig. 8 that the PL intensity of ZnB₂O₄: Eu³⁺, Tb³⁺ enhances with the increase in the calcination time and reaches a maximum at 6 h because of the better crystallization, however the intensity decreases dramatically when the calcination time prolong to 9 h. It may be the agglomeration and larger particle size of ZnB₂O₄: Eu³⁺, Tb³⁺ phosphors that lead to the increasing of surface defects and decreasing of exciting surface area.^{Reference Huang and Liu12}

FIG. 8.

Emission spectra of the ZnB₂O₄: Eu³⁺, Tb³⁺ (A-900) prepared by calcining the precursor at 900 °C for various times: (a)3 h, (b)6 h, (c)9 h.

F. Comparing study of ZnB₂O₄: Eu³⁺, Tb³⁺ prepared by precursor method and solid-state reaction method

Figures 2 and 9 show the XRD patterns and the SEM images of ZnB₂O₄: Eu³⁺, Tb³⁺, and ZnB₂O₄: Eu³⁺ phosphors prepared by present precursor method and conventional solid-state reaction method at 900 °C, respectively.

FIG. 9.

SEM image of samples: (A) ZnB₂O₄: Eu³⁺, Tb³⁺ (A-900), (B) ZnB₂O₄: Eu³⁺, Tb³⁺(B-900), (C) ZnB₂O₄: Eu³⁺.

As shown in Fig. 10, the emission peak positions of the ZnB₂O₄: Eu³⁺, Tb³⁺ samples are almost the same, but the emission intensities are varied with different synthesis method. For the same reaction temperature and time, the emission intensity of ZnB₂O₄: Eu³⁺, Tb³⁺ phosphor prepared by the present precursor method is much higher than that of ZnB₂O₄: Eu³⁺, Tb³⁺ prepared by solid-state reaction method. The improvement of emission intensity is ascribed to the relatively larger particle size and smoother particle surface when using the precursor method as shown in Fig. 9(a).^{Reference Huang and Liu12}

FIG. 10.

Emission spectra of ZnB₂O₄: Eu³⁺, Tb³⁺ (A-900) and ZnB₂O₄: Eu³⁺, Tb³⁺ (B-900) prepared through two different approaches: (a) precursor method, (b) solid-state reaction method.

As shown in Fig. 11, ZnB₂O₄: Eu³⁺, Tb³⁺ phosphor prepared by the present precursor method not only has stronger emission intensity but also exhibits higher red to orange intensity ratio (R/O) than those of ZnB₂O₄: Eu³⁺ phosphor, which may be explained by energy transfer between Tb³⁺ and Eu³⁺.^{Reference Som and Sharma10}

FIG. 11.

Emission spectra of (a) ZnB₂O₄: Eu³⁺, Tb³⁺(A-900) and (b)ZnB₂O₄: Eu³⁺.

All these results indicate that the PL intensity and color purity of ZnB₂O₄: Eu³⁺, Tb³⁺ could be enhanced largely by the present precursor method.

IV. CONCLUSIONS

ZnB₂O₄: Eu³⁺, Tb³⁺ phosphors were successfully obtained by calcining of Zn[B₃O₃(OH)₅]·H₂O: Eu³⁺, Tb³⁺ precursor for the first time. The ZnB₂O₄: Eu³⁺, Tb³⁺ phosphor with maximum luminescent intensity was obtained by calcining Zn[B₃O₃(OH)₅]·H₂O: Eu³⁺, Tb³⁺ precursor at 900 °C for 6 h. The ZnB₂O₄: Eu³⁺, Tb³⁺ phosphor prepared by this method exhibits much stronger emission intensity than that synthesized by conventional high temperature solid-state method. Moreover, the introduction of Tb³⁺ ions successfully enhanced largely not only the emission intensity but also the color purity.

ACKNOWLEDGMENT

Project supported by National Natural Science Foundation of China (Nos. 21173143 and 21573142).

References

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FIG. 1. EDS of samples: (a) Zn[B3O3(OH)5]·H2O: Eu3+, Tb3+; (b) ZnB2O4: Eu3+, Tb3+ (A-900); (c) ZnB2O4: Eu3+, Tb3+ (B-900).

FIG. 2. XRD patterns of samples: (a) Zn[B3O3(OH)5]·H2O: Eu3+, Tb3+; (b) ZnB2O4: Eu3+, Tb3+ (A-900); (c) ZnB2O4: Eu3+, Tb3+ (B-900); (d) ZnB2O4: Eu3+.

FIG. 3. The FT-IR spectra of samples: (a) Zn[B3O3(OH)5]·H2O: Eu3+, Tb3+; (b) ZnB2O4: Eu3+, Tb3+(A-900); (c) ZnB2O4: Eu3+, Tb3+ (B-900).

FIG. 4. The excitation (insert) and emission spectra of ZnB2O4: Eu3+, Tb3+.

FIG. 5. (A) The PL spectra of Zn[B3O3(OH)5]·H2O: 0.06Eu3+, yTb3+ samples: (a) 2%, (b) 3%, (c) 5%, (d) 10%, (e) 15%; (B) The PL spectra of ZnB2O4: 6%Eu3+, yTb3+ samples: (a) 1%, (b) 1.5%, (c) 2%, (d) 2.5%, (e) 3%.

FIG. 6. XRD patterns of samples prepared by calcining the precursor at various temperatures:(a) A-700, (b) A-800, (c) A-900.

FIG. 7. Emission spectra of samples prepared by calcining the precursor at various temperatures:(a) A-700, (b) A-800, (c) A-900.

FIG. 8. Emission spectra of the ZnB2O4: Eu3+, Tb3+ (A-900) prepared by calcining the precursor at 900 °C for various times: (a)3 h, (b)6 h, (c)9 h.

FIG. 9. SEM image of samples: (A) ZnB2O4: Eu3+, Tb3+ (A-900), (B) ZnB2O4: Eu3+, Tb3+(B-900), (C) ZnB2O4: Eu3+.

FIG. 10. Emission spectra of ZnB2O4: Eu3+, Tb3+ (A-900) and ZnB2O4: Eu3+, Tb3+ (B-900) prepared through two different approaches: (a) precursor method, (b) solid-state reaction method.

FIG. 11. Emission spectra of (a) ZnB2O4: Eu3+, Tb3+(A-900) and (b)ZnB2O4: Eu3+.

Article contents

Enhanced photoluminescence property of co-doped ZnB2O4: Eu3+, Tb3+ phosphor prepared by a thermal conversion method

Abstract

Keywords

Information

I. INTRODUCTION

II. EXPERIMENTAL

A. Preparation of Zn[B3O3(OH)5]·H2O: Eu3+, Tb3+ precursor

B. Preparation of ZnB2O4: Eu3+, Tb3+ phosphors

C. Characterization

III. RESULTS AND DISCUSSION

A. Phase identification and morphology

B. The excitation and emission spectra of ZnB2O4: Eu3+, Tb3+

C. The effect of doped concentration on the PL intensity of ZnB2O4: Eu3+, Tb3+

D. Effect of the calcination temperature on the PL properties of ZnB2O4: Eu3+, Tb3+

E. Effect of the calcination time on the PL properties of ZnB2O4: Eu3+, Tb3+

F. Comparing study of ZnB2O4: Eu3+, Tb3+ prepared by precursor method and solid-state reaction method

IV. CONCLUSIONS

ACKNOWLEDGMENT

References

REFERENCES

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Conflicting interests

A. Preparation of Zn[B₃O₃(OH)₅]·H₂O: Eu³⁺, Tb³⁺ precursor

B. Preparation of ZnB₂O₄: Eu³⁺, Tb³⁺ phosphors

B. The excitation and emission spectra of ZnB₂O₄: Eu³⁺, Tb³⁺

C. The effect of doped concentration on the PL intensity of ZnB₂O₄: Eu³⁺, Tb³⁺

D. Effect of the calcination temperature on the PL properties of ZnB₂O₄: Eu³⁺, Tb³⁺

E. Effect of the calcination time on the PL properties of ZnB₂O₄: Eu³⁺, Tb³⁺

F. Comparing study of ZnB₂O₄: Eu³⁺, Tb³⁺ prepared by precursor method and solid-state reaction method