Terbium or dysprosium doped modified tellurite glass and preparation method thereof

Abstract

The present invention provides a terbium- or dysprosium-doped modified tellurite glass with excellent luminescence properties and a preparation method thereof. The glass is prepared from the following raw materials by weight: 60-70 parts TeO2, 10-20 parts Ca2CO3, 5-15 parts Na2CO3, 1-10 parts Nb2O5, 1-10 parts chloride, and 0.5-5 parts dopant; the chloride is MgCl2 or ZnCl2, and the dopant is Tb2O3 or Dy2O3. The preparation method is simple, has low equipment and environmental requirements, and is conducive to industrial production. The glass has good forming ability, overcomes the problem of glass being easily crystallized, and has excellent optical properties, making it well suited for use in the field of fiber optic sensing.

Description

Technical Field

[0001] The invention relates to terbium or dysprosium doped modified tellurite glass and a preparation method thereof, belonging to the technical field of solid luminescent materials. Background Art

[0002] Telluride glasses have been extensively studied in recent years due to their advantages, including good transparency (0.35–5 μm), high refractive index and nonlinear refractive index compared to silicate glasses (0.2–3 μm), and improved stability and corrosion resistance compared to fluoride glasses. Both germanate and tellurite glasses are heavy metal oxide glasses, but their high melting points and high prices limit the practical applications of germanate. Telluride glasses are considered ideal host glasses for rare earth ions due to their low phonon energy (750 nm, lower than that of phosphate and silicate glasses), high rare earth ion solubility, good thermal stability, and low thermal expansion coefficient, which minimize non-radiative losses.

[0003] Reports on tellurite glass have been published in the prior art. For example, Chinese patent document CN103359939A discloses a green-light tellurite glass and its preparation method. The green-light tellurite glass is prepared from 65-90 mol% TeO2, 5-25 mol% ZnO, 3-20 mol% Na2O, an ytterbium ion compound with a mass percentage concentration of 2-8%, and a terbium ion compound with a mass percentage concentration of 1-4%. This invention provides a tellurite glass matrix that can emit strong visible green light and can be doped with a large amount of rare earth ions, as well as a green-light tellurite glass with a simple and feasible preparation process and its preparation method. However, the refractive index, thermal stability, rare earth ion doping concentration, and spectral properties of the tellurite glass are mainly determined by the components of the tellurite glass. The components of the tellurite glass in this invention still have relatively large phonon energies, which is not conducive to further improving optical performance. Considering the importance of the physicochemical stability of the glass matrix and the maximum phonon energy for improving its spectral properties, appropriate glass modifiers can be incorporated. The low phonon energy of fluorides can lead to optimized structure and luminescence properties, but fluoride glasses have poor thermal properties. Therefore, further research is needed to further improve the optical properties of tellurite glasses and further optimize their structure and properties. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention provides a terbium- or dysprosium-doped modified tellurite glass with excellent luminescence properties and a method for preparing the same. The present invention's preparation method is simple, requires minimal equipment and environmental requirements, and is therefore amenable to industrial production. The glass exhibits excellent formability, overcomes the problem of glass crystallization, and exhibits excellent optical properties, making it well-suited for use in fiber optic sensing.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A terbium- or dysprosium-doped modified tellurite glass is prepared from the following raw materials in parts by mass: 60-70 parts of TeO2, 10-20 parts of Ca2CO3, 5-15 parts of Na2CO3, 1-10 parts of Nb2O5, 1-10 parts of chloride, and 0.5-5 parts of dopant; the chloride is MgCl2 or ZnCl2, and the dopant is Tb2O3 or Dy2O3.

[0007] Preferably, according to the present invention, the terbium or dysprosium doped modified tellurite glass is prepared by including the following raw materials in parts by mass: 65-66 parts of TeO2, 14-15 parts of Ca2CO3, 9-10 parts of Na2CO3, 4-5 parts of Nb2O5, 4-6 parts of chloride, and 0.5-2 parts of dopant.

[0008] Preferably, the terbium or dysprosium doped modified tellurite glass is prepared by including the following raw materials in parts by mass: 65.8 parts of TeO2, 14.1 parts of Ca2CO3, 9.4 parts of Na2CO3, 54.7 parts of Nb2O5, 5 parts of chloride, and 1 part of dopant.

[0009] Most preferably, the terbium or dysprosium doped modified tellurite glass is prepared by including the following raw materials in parts by mass: 65.8 parts of TeO2, 14.1 parts of Ca2CO3, 9.4 parts of Na2CO3, 54.7 parts of Nb2O, 25 parts of ZnCl, and 31 parts of Dy2O.

[0010] Most preferably, the terbium or dysprosium doped modified tellurite glass is prepared by including the following raw materials in parts by mass: 65.8 parts of TeO2, 14.1 parts of Ca2CO3, 9.4 parts of Na2CO3, 54.7 parts of Nb2O, 25 parts of MgCl, and 1 part of Tb2O3.

[0011] The method for preparing the terbium- or dysprosium-doped modified tellurite glass comprises the following steps:

[0012] TeO2, Ca2CO3, Na2CO3, Nb2O5, chloride and dopant are fully ground and mixed to obtain a mixture; then terbium or dysprosium doped modified tellurite glass is obtained through sintering, annealing, cooling and polishing.

[0013] According to the present invention, preferably, the grinding and mixing temperature is room temperature, the grinding and mixing time is 5-40 minutes, and the grinding is carried out in the same direction.

[0014] According to the preferred embodiment of the present invention, the sintering temperature is 900-1000° C., the sintering time is 30-40 min, and the sintering atmosphere is air.

[0015] According to the present invention, preferably, the annealing temperature is 250-300° C., the annealing time is 1-3 hours, and the annealing atmosphere is air.

[0016] According to the present invention, preferably, cooling is natural cooling to room temperature.

[0017] Preferably, according to the present invention, if the glass needs to be shaped, the sintered glass liquid needs to be placed on a preheated copper prefabricated plate before annealing, and after shaping, annealing treatment is quickly performed; wherein the temperature of the preheated copper prefabricated plate is lower than the glass transition temperature.

[0018] The technical features and beneficial effects of the present invention are as follows:

[0019] 1. The preparation method of the present invention is simple, has low requirements on equipment and environment, and is conducive to industrial production.

[0020] 2. The low phonon energy of fluoride can optimize the glass structure and luminescence properties, but the thermal properties of fluoride glass are poor. The addition of chlorides of halogen elements with similar properties to fluoride to the matrix of the terbium or dysprosium-doped tellurite glass of the present invention can not only further improve the optical properties, but also overcome the disadvantages of introducing fluoride.

[0021] 3. This invention innovatively introduces chloride into tellurite glass, promoting improvements in various properties. For example, the glass becomes denser and more thermally stable, accompanied by structural changes. Stable thermal conditions and a dense structure are generally beneficial for the luminescence of rare earth ions. Furthermore, this invention compares the degree of improvement in the optical properties of terbium- or dysprosium-doped tellurite glasses by MgCl₂ and ZnCl₂.

[0022] 4. The excellent effects of the present invention can only be achieved when all the raw material components work together as a whole. The chloride content must be appropriate; excessive chloride content can cause glass penetration, while too little chloride content will not achieve its desired effect. The glass with the structure and effects of the present invention can only be produced by combining the specific types and ratios of the glass matrix components of the present invention with the specific types and ratios of dopants and chlorides. Replacing any one component or using an inappropriate ratio will not achieve the excellent effects of the present invention.

[0023] 5. The terbium-doped tellurite glass of the present invention, under excitation at 377 nm, emits bright light with peaks at 485 nm, 545 nm, 572 nm, and 621 nm. Both MgCl2 and ZnCl2 can enhance the luminescence intensity of terbium ions, with MgCl2 significantly improving luminescence intensity more than ZnCl2. The dysprosium-doped tellurite glass, under excitation at 425 nm, emits bright light with peaks at 485 nm, 575 nm, and 670 nm. Both MgCl2 and ZnCl2 can enhance the luminescence intensity of dysprosium ions, with ZnCl2 significantly improving luminescence intensity more than MgCl2. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The fluorescence spectra of the terbium-doped tellurite glasses prepared in Examples 1-2 and Comparative Example 1 under 377 nm excitation are shown;

[0025] Figure 2 The fluorescence spectra of the dysprosium-doped tellurite glasses prepared in Examples 3-4 and Comparative Example 2 under 425 nm excitation are shown. DETAILED DESCRIPTION

[0026] The present invention will be further described below with reference to specific embodiments and drawings, but is not limited thereto.

[0027] Unless otherwise specified, the raw materials and equipment used in the examples are all conventional products; unless otherwise specified, the methods used are all from the prior art.

[0028] Example 1:

[0029] A terbium-doped MgCl2 tellurite glass is prepared from the following raw materials in percentage by weight: TeO2 65.8%, Ca2CO3 14.1%, Na2CO3 9.4%, Nb2O 54.7%, MgCl2 5%, and Tb2O 31%. The purity of each raw material is required to be 99.99%, and the total weight of the raw materials is 10g.

[0030] The method for preparing the terbium-doped MgCl2 tellurite glass comprises the following steps:

[0031] TeO2, Ca2CO3, Na2CO3, Nb2O5, MgCl2, and Tb2O3 were ground in a mortar in a clockwise direction at room temperature for 10 minutes. After thorough grinding, the mixture was transferred to a corundum crucible. The crucible was then sintered in air at 950°C for 30 minutes in a pit furnace. The sample powder was removed after full sintering. The resulting glass liquid was placed on a copper preform preheated to 350°C to form a disc. This disc was then quickly transferred to an annealing furnace at 280°C for 2 hours in an air atmosphere. After annealing, the disc was allowed to cool naturally to room temperature. The resulting tellurite glass disc was then thinned to a 1.5 cm × 1.5 cm × 1.5 mm cube and polished until transparent, resulting in a double-sided polished tellurite glass disc.

[0032] Example 2:

[0033] A terbium-doped ZnCl2 tellurite glass is prepared from the following raw materials in percentage by weight: TeO2 65.8%, Ca2CO3 14.1%, Na2CO3 9.4%, Nb2O 54.7%, ZnCl25%, and Tb2O 31%. The purity of each raw material is required to be 99.99%, and the total weight of the raw materials is 10g.

[0034] The method for preparing the terbium-doped ZnCl2 tellurite glass comprises the following steps:

[0035] TeO2, Ca2CO3, Na2CO3, Nb2O5, ZnCl2, and Tb2O3 were ground in a mortar in a clockwise direction at room temperature for 10 minutes. After thorough grinding, the mixture was transferred to a corundum crucible. The crucible was then sintered in air at 950°C for 30 minutes in a pit furnace. The sample powder was removed after full sintering. The resulting glass liquid was placed on a copper preform preheated to 350°C to form a disc. This disc was then quickly transferred to an annealing furnace at 280°C for 2 hours in an air atmosphere. After annealing, the disc was allowed to cool naturally to room temperature. The resulting tellurite glass disc was then thinned to a 1.5 cm × 1.5 cm × 1.5 mm cube and polished until transparent, resulting in a double-sided polished tellurite glass disc.

[0036] Example 3:

[0037] A dysprosium-doped MgCl2 tellurite glass is prepared from the following raw materials in percentage by weight: TeO2 65.8%, Ca2CO3 14.1%, Na2CO3 9.4%, Nb2O 54.7%, MgCl2 5%, and Dy2O 31%. The purity of each raw material is required to be 99.99%, and the total weight of the raw materials is 10g.

[0038] The preparation method of the above-mentioned dysprosium-doped MgCl2 tellurite glass is the same as that of Example 1.

[0039] Example 4:

[0040] A dysprosium-doped ZnCl2 tellurite glass is prepared from the following raw materials in percentage by weight: TeO2 65.8%, Ca2CO3 14.1%, Na2CO3 9.4%, Nb2O 54.7%, ZnCl25%, and Dy2O 31%. The purity of each raw material is required to be 99.99%, and the total weight of the raw materials is 10g.

[0041] The preparation method of the above-mentioned dysprosium-doped ZnCl2 tellurite glass is the same as that of Example 1.

[0042] Comparative Example 1:

[0043] A terbium-doped tellurite glass, as described in Example 1, except that no halide is added, is prepared from the following raw materials: 6.58 g TeO2, 1.41 g Ca2CO3, 0.94 g Na2CO3, 0.47 g Nb2O5, and 0.1 g Tb2O3. The purity of each raw material is required to be 99.99%.

[0044] The preparation method of the terbium-doped tellurite glass is the same as that of Example 1.

[0045] Comparative Example 2:

[0046] A dysprosium-doped tellurite glass, as described in Example 3, except that no halide is added, is prepared from the following raw materials: 6.58 g TeO2, 1.41 g Ca2CO3, 0.94 g Na2CO3, 0.47 g Nb2O5, and 0.1 g Dy2O3. The purity of each raw material is required to be 99.99%.

[0047] The preparation method of the dysprosium-doped tellurite glass is the same as that of Example 3.

[0048] Test Example 1

[0049] Fluorescence spectrum test

[0050] Figure 1The fluorescence spectra of the terbium-doped tellurite glasses prepared in Examples 1-2 and Comparative Example 1 under 377nm excitation are shown. The fluorescence spectrum of the terbium-doped tellurite glass prepared in Comparative Example 1 under λ = 377nm excitation shows a gain spectrum range of approximately 450-650nm. The spectrum exhibits distinct emission peaks near 485nm, 545nm, 572nm, and 621nm. Furthermore, the emission peak intensities are enhanced when halides are added compared to those without halides. Furthermore, the emission peak intensity of the terbium-doped tellurite glass with MgCl2 is significantly stronger than that of the terbium-doped tellurite glass with ZnCl2. This indicates that both MgCl2 and ZnCl2 in terbium-doped tellurite glass can enhance the luminescence intensity of Tb ions, with MgCl2 having a greater effect than that of Tb ions.

[0051] Figure 2 The fluorescence spectra of the dysprosium-doped tellurite glasses prepared in Examples 3-4 and Comparative Example 2 under 425nm excitation are shown. The fluorescence spectrum of the dysprosium-doped tellurite glass prepared in Comparative Example 2 under λ = 425nm excitation shows a gain spectrum range of approximately 450-700nm. The spectrum exhibits distinct emission peaks near 485nm, 575nm, and 670nm. Furthermore, the emission peak intensities are enhanced when halides are added compared to those without halides. Furthermore, the emission peak intensity of the dysprosium-doped tellurite glass with ZnCl2 is significantly stronger than that of the dysprosium-doped tellurite glass with MgCl2. This indicates that both MgCl2 and ZnCl2 in dysprosium-doped tellurite glass can enhance the luminescence intensity of Dy ions, with ZnCl2 having a greater effect than that of Dy ions.

[0052] Test Example 2

[0053] Fluorescence lifetime test

[0054] The fluorescence lifetimes of the terbium-doped tellurite glasses prepared in Examples 1-2 and Comparative Example 1 under 350nm excitation were tested. The fluorescence lifetimes of the terbium-doped tellurite glasses without chloride addition were 0.882ms, the fluorescence lifetimes of the terbium-doped tellurite glasses with MgCl2 added were 0.916ms, and the fluorescence lifetimes of the terbium-doped tellurite glasses with ZnCl2 added were 0.901ms. The fluorescence lifetimes of the glasses with chloride addition were significantly longer than those without chloride addition, and the fluorescence lifetimes of the terbium-doped tellurite glasses with MgCl2 added were significantly longer than those with ZnCl2 added. This indicates that both MgCl2 and ZnCl2 in terbium-doped tellurite glasses can increase the fluorescence lifetime of Tb ions, with MgCl2 having a greater effect on Tb ions.

[0055] The fluorescence lifetimes of the dysprosium-doped tellurite glasses prepared in Examples 3-4 and Comparative Example 2 under 425nm excitation were tested. Without the addition of chloride, the fluorescence lifetime of dysprosium was 0.242ms, while that of the dysprosium-doped tellurite glass with the addition of ZnCl2 was 0.259ms, and that of the dysprosium-doped tellurite glass with the addition of MgCl2 was 0.257ms. The fluorescence lifetimes of the glasses with the addition of chloride increased compared to those without the addition of chloride, and the fluorescence lifetime of the dysprosium-doped tellurite glass with the addition of ZnCl2 was longer than that of the glass with the addition of MgCl2. This indicates that both MgCl2 and ZnCl2 in dysprosium-doped tellurite glasses can increase the fluorescence lifetime of Dy ions, with ZnCl2 having a greater effect on Dy ions.

Claims

1. A terbium or dysprosium doped modified tellurite glass, characterized in that: The terbium or dysprosium doped modified tellurite glass is prepared from the following raw materials in parts by weight: 65.8 parts of TeO2, 14.1 parts of Ca2CO3, 9.4 parts of Na2CO3, 4.7 parts of Nb2O5, 5 parts of ZnCl2, and 1 part of Dy2O3; Alternatively, the terbium- or dysprosium-doped modified tellurite glass is prepared from the following raw materials in parts by mass: 65.8 parts of TeO2, 14.1 parts of Ca2CO3, 9.4 parts of Na2CO3, 4.7 parts of Nb2O5, 5 parts of MgCl2, and 1 part of Tb2O3.

2. The method for preparing the terbium- or dysprosium-doped modified tellurite glass according to claim 1, comprising the steps of: Thoroughly grind and mix TeO2, Ca2CO3, Na2CO3, Nb2O5, ZnCl2, and Dy2O3 to obtain a mixture; or, thoroughly grind and mix TeO2, Ca2CO3, Na2CO3, Nb2O5, MgCl2, and Tb2O3 to obtain a mixture; Then the mixture is sintered, annealed, cooled and polished to obtain terbium or dysprosium doped modified tellurite glass.

3. The method for preparing terbium- or dysprosium-doped modified tellurite glass according to claim 2, characterized in that: The grinding and mixing temperature is room temperature, and the grinding and mixing time is 5-40 minutes; Grinding is done in the same direction.

4. The method for preparing terbium- or dysprosium-doped modified tellurite glass according to claim 2, wherein: The sintering temperature is 900-1000°C, the sintering time is 30-40 minutes, and the sintering atmosphere is air.

5. The method for preparing terbium- or dysprosium-doped modified tellurite glass according to claim 2, wherein: The annealing temperature is 250-300°C, the annealing time is 1-3h, and the annealing atmosphere is air.

6. The method for preparing terbium- or dysprosium-doped modified tellurite glass according to claim 2, wherein: Cooling is natural cooling to room temperature.

7. The method for preparing terbium- or dysprosium-doped modified tellurite glass according to claim 2, wherein: If the glass needs to be shaped, before annealing, the sintered glass liquid needs to be placed on a preheated copper prefabricated plate. After shaping, annealing treatment is quickly performed; wherein, the temperature of the preheated copper prefabricated plate is lower than the glass transition temperature.

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