Rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable luminescent glass, preparation method and application thereof

Abstract

The invention discloses rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable luminescent glass, and a preparation method and application thereof, the luminescent glass can realize luminescence tuning from a yellow green area to an orange red area under excitation of light with different wavelengths, has good luminescence stability and thermal stability, and can be widely applied to the fields of WLED or solid-state illumination luminescence and the like. The rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable luminescent glass disclosed by the invention is prepared from the following raw materials in percentage by mass: 50.0 to 60.0 percent of P2O5, 15.0 to 25.0 percent of H3BO3, 10.0 to 20.0 percent of Al2O3, 1.0 to 6.0 percent of Li2CO3, 1.0 to 7.5 percent of K2CO3, 0.5 to 3.0 percent of Gd2O3, 0.5 to 1.0 percent of Dy2O3, 0.1 to 0.5 percent of Tb4O7 and 0.3 to 0.9 percent of Eu2O3.

Description

Technical Field

[0001] This invention relates to a light-emitting glass, its preparation method, and its application; more specifically, it relates to a rare earth element Dy / Tb / Eu co-doped aluminum boron phosphate tunable light-emitting glass, its preparation method, and its application, belonging to the field of optical materials technology. Background Technology

[0002] White light-emitting diodes (WLEDs) have been widely used in high-tech fields such as lighting, display devices, and optical communications due to their low power consumption, excellent luminous efficiency, environmental friendliness, and outstanding reliability. Currently, mainstream WLEDs primarily employ a binary light-emitting mechanism of a blue light chip coupled with yellow phosphors. However, this technology suffers from significant spectral defects, such as a lack of effective red light components, resulting in white light with a cool-toned appearance, specifically manifested as a low color rendering index (CRI < 75) and a high correlated color temperature (CCT > 4500K). More seriously, the thermal stability defects of the phosphor and epoxy resin in the packaging system lead to thermal degradation effects, causing a significant shift in the photoluminescence spectrum and resulting in unstable emission color, severely impacting lighting quality and device lifespan. Therefore, researching the use of rare-earth element-doped glass luminescence is one effective option for solving these problems.

[0003] Current research on luminescent glasses mainly focuses on borate, silicate, and phosphate glass systems. Phosphate glasses are commonly used to prepare rare-earth-doped luminescent glasses due to their low cost, high rare-earth solubility, moderate phonon energy, and excellent luminescence performance. However, the double-bonded oxygen atoms in their structure cause uneven electric field distribution, the PO network is prone to breakage, and their poor chemical stability and moisture resistance limit their application range. 3+ 、Tb 3+ and Dy 3+ These three rare earth ions, due to their unique luminescence properties in the visible spectrum, have become one of the main research subjects for improving the optical properties of glass. 3+ The ions exhibit orange emission near 596 nm and red emission near 621 nm. 5 D0→ 7 F J Transition, J = 0-4); Tb 3+ It exhibits green light emission around 544nm. 5 D4→ 7 F5 jump); while Dy 3+ The yellow emission corresponds to 4 F 9 / 2 → 6 H 13 / 2 Leap. Utilizing Dy 3+ The yellow light emitted by Tb 3+ Eu 3+Combining green, red, and orange light can improve and enhance the quality of white light emission, potentially leading to high-intensity warm white light emission. Therefore, developing and selecting these three rare earth elements as luminescent ions for aluminum boron phosphate to prepare tunable luminescent glass can address the shortcomings of existing WLEDs in terms of red component and poor optical quality, thus resolving current technological limitations. Summary of the Invention

[0004] This invention addresses the problems and shortcomings of existing technologies by providing a rare-earth element Dy / Tb / Eu co-doped aluminum boron phosphate tunable light-emitting glass. This glass can achieve luminescence tuning from the yellow-green region to the orange-red region under different wavelengths of light excitation. Under 386nm excitation, its color coordinates are (0.505, 0.425), corresponding to a CCT of 2258K. The emitted color is a warm white hue, with a fluorescence lifetime of 2.366ms. Furthermore, it retains over 85% of its original luminous intensity at 450K, exhibiting excellent luminous and thermal stability. It can be applied in WLED or solid-state lighting fields, demonstrating broad application prospects.

[0005] Meanwhile, the present invention also provides a method for preparing the rare earth element Dy / Tb / Eu co-doped aluminum boron phosphate tunable light-emitting glass. The preparation method and process are simple, the production cost is low, and it is easy to scale up production.

[0006] This invention is achieved through the following technical solution:

[0007] The rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable luminescent glass of the present invention is made from the following raw materials in the following mass ratio: P2O5 50.0-60.0%, H3BO3 15.0-25.0%, Al2O3 10.0-20.0%, Li2CO3 1.0-6.0%, K2CO3 1.0-7.5%, Gd2O3 0.5-3.0%, rare earth oxide Dy2O3 0.5-1.0%, rare earth oxide Tb4O7 0.1-0.5%, and rare earth oxide Eu2O3 0.3-0.9%.

[0008] The rare earth element Dy / Tb / Eu co-doped aluminum boron phosphate tunable light-emitting glass of the present invention further provides that the rare earth element Dy / Tb / Eu co-doped aluminum boron phosphate tunable light-emitting glass produces excellent warm white light emission under 386nm wavelength excitation, with color coordinates of (0.505, 0.425) and corresponding CCT of 2258K, and the emitted color belongs to the warm white light hue.

[0009] The preparation method of the rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable light-emitting glass of the present invention is carried out by high-temperature melting and quenching method, and includes the following steps:

[0010] 1) After accurately weighing the raw materials, grind and mix them until they are evenly mixed to obtain glass premix;

[0011] 2) Transfer the uniformly mixed glass premix to a crucible and place it in a high-temperature furnace; set the high-temperature furnace heating program and heat it to 1150-1250℃ at a heating rate of 5-10℃ / min, and hold it at this temperature for 5.0-7.0 hours so that Eu is entirely present in the glass in the +3 oxidation state. After the raw material is fully melted, a completely molten glass material is obtained.

[0012] 3) The fully molten glass material is cast onto a copper plate at 400-480℃ and held at this temperature for 1.5-5.0 hours to eliminate the thermal stress inside the aluminum borosilicate glass. Then, it is cooled to room temperature with the furnace to obtain rare earth element Dy / Tb / Eu co-doped aluminum borosilicate tunable luminescent glass.

[0013] The rare earth element Dy / Tb / Eu co-doped aluminum boron phosphate tunable light-emitting glass described above can be used in WLED or solid-state lighting.

[0014] Compared with the prior art, the present invention has the following advantages:

[0015] The composition and ratio of the glass matrix play a crucial role in the luminescence properties of rare earth ions. This invention addresses the shortcomings of existing WLEDs in terms of red component and poor optical quality by designing the glass composition to effectively introduce rare earth elements into the glass structure, thereby improving the luminescence performance of existing WLEDs. This invention introduces B2O3 into the phosphate network to form POB cross-linking bonds, thereby improving the mechanical strength and chemical stability of the aluminoborosilicate glass. Simultaneously, the introduction of Al2O3 promotes the formation of [AlO4] tetrahedra in the glass network, improving the thermal stability and mechanical properties of the matrix glass, increasing the critical distance between rare earth ions, reducing non-radiative decay, and increasing photoluminescence intensity. To further improve the glass's density, reflectivity, strength, and stability, while reducing phonon energy and improving its optical properties, Gd2O3 is added to the glass composition. To improve glass melting performance, alkali metal oxides Li2O and K2O are added as glass network modifiers. The addition of alkali metal oxides can also reduce the phonon energy of the aluminoborosilicate glass system, enhancing the glass's luminescence performance. The addition of rare earth oxides and network modifiers provides a favorable material composition for achieving efficient, stable, and tunable white light-emitting diodes (WLEDs).

[0016] This invention uses aluminum borophosphate as the glass matrix and rare earth elements Dy / Tb / Eu as the luminescent agent. A tunable luminescent glass co-doped with rare earth elements Dy / Tb / Eu is prepared using a melt-quenching method. By adjusting the glass raw materials, composition, and ratio, as well as the type and concentration of rare earth oxides, the luminescent properties of the glass are improved. The tunable luminescent glass co-doped with rare earth elements Dy / Tb / Eu of this invention produces excellent warm white light emission under 386nm excitation, with color coordinates (0.505, 0.425) and a corresponding CCT of 2258K. The emitted color is a warm white hue, with a fluorescence lifetime of 2.366ms. Furthermore, it retains more than 85% of its original luminescence intensity at 450K, exhibiting good luminescent and thermal stability.

[0017] The rare earth element Dy / Tb / Eu co-doped aluminum boron phosphate tunable light-emitting glass of the present invention has broad application prospects in WLED and solid-state lighting fields. The preparation method using melt quenching is simple, easy to scale up, and is a highly efficient, energy-saving, safe and effective glass preparation method that can effectively reduce preparation costs while ensuring glass quality. Attached Figure Description

[0018] Figure 1 These are the excitation and emission spectra of aluminum borosilicate luminescent glass doped with different concentrations of Dy / Tb / Eu according to the present invention; wherein, (a) is the excitation spectrum, and (b), (c) and (d) are the emission spectra when excited at 349 nm, 364 nm and 386 nm, respectively.

[0019] Figure 2 These are CIE chromaticity coordinate diagrams of aluminum borosilicate luminescent glasses doped with different concentrations of Dy / Tb / Eu according to the present invention; wherein (a), (b) and (c) are CIE diagrams excited at 349nm, 364nm and 386nm, respectively.

[0020] Figure 3 This is the fluorescence lifetime decay curve of aluminum borophosphate light-emitting glass doped with different concentrations of Dy / Tb / Eu according to the present invention, when excited at a wavelength of 386nm and emitted at a wavelength of 575nm.

[0021] Figure 4 The following is a temperature-varying emission spectrum of the rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable light-emitting glass of Example 2; wherein, (a) is the temperature-varying emission spectrum and (b) is the combined intensity spectrum at different temperatures. Detailed Implementation

[0022] The preparation methods of the rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable light-emitting glass in Examples 1-3 are as follows:

[0023] 1) After accurately weighing the raw materials, grind and mix them until they are evenly mixed to obtain glass premix;

[0024] 2) Transfer the uniformly mixed glass premix to a crucible and place it in a high-temperature furnace; set the high-temperature furnace heating program and heat it to 1150-1250℃ at a heating rate of 5-10℃ / min, and hold it at this temperature for 5.0-7.0 hours so that Eu is entirely present in the glass in the +3 oxidation state. After the raw material is fully melted, a completely molten glass material is obtained.

[0025] 3) The fully molten glass material is cast onto a copper plate at 400-480℃ and held at this temperature for 1.5-5.0 hours to eliminate the thermal stress inside the aluminum borosilicate glass. Then, it is cooled to room temperature with the furnace to obtain rare earth element Dy / Tb / Eu co-doped aluminum borosilicate tunable luminescent glass.

[0026] The mass percentages of the raw materials and their composition in Examples 1-3 are shown in Table 1.

[0027] Table 1. Raw materials and their mass percentages for the preparation of rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable luminescent glass in Examples 1-3.

[0028]

[0029] Example 1

[0030] The rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable light-emitting glass of this embodiment has raw materials and mass percentages shown in Table 1.

[0031] The preparation steps of the rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable light-emitting glass in this embodiment are as follows:

[0032] Step 1: Raw material weighing: Using P2O5, H3BO3, Al2O3, Li2CO3, K2CO3, Gd2O3, Dy2O3, Tb4O7, and Eu2O3 as raw materials, weigh them according to the mass percentage requirements in Table 1;

[0033] Step 2: Preparation of glass premix: Grind and mix the weighted glass raw materials and rare earth oxides to obtain a uniformly mixed glass premix;

[0034] Step 3: Preparation of fully molten glass: Transfer the uniformly mixed raw materials to a crucible and place it in a high-temperature furnace. Set the high-temperature furnace heating program to heat to 1150°C at a heating rate of 5°C / min, and hold at this temperature for 7.0 hours to ensure that Eu is entirely present in the +3 oxidation state in the glass. After the raw materials are fully melted, a fully molten glass is obtained.

[0035] Step 4: Annealing of the luminescent glass: The above fully molten glass material is cast onto a copper plate at 400°C and held at this temperature for 5.0 hours. Then it is cooled to room temperature in the furnace to obtain rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable luminescent glass, and its sample is marked as DTE1.

[0036] Implement column 2

[0037] The rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable light-emitting glass of this embodiment has raw materials and mass percentages shown in Table 1.

[0038] The preparation steps of the rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable light-emitting glass in this embodiment are as follows:

[0039] Step 1: Raw material weighing: Using P2O5, H3BO3, Al2O3, Li2CO3, K2CO3, Gd2O3, Dy2O3, Tb4O7, and Eu2O3 as raw materials, weigh them according to the mass percentage requirements in Table 1;

[0040] Step 2: Preparation of glass premix: Grind and mix the weighted glass raw materials and rare earth oxides to obtain a uniformly mixed glass premix;

[0041] Step 3: Preparation of fully molten glass: Transfer the uniformly mixed raw materials to a crucible and place it in a high-temperature furnace. Set the high-temperature furnace heating program to heat to 1250°C at a heating rate of 10°C / min, and hold at this temperature for 5.0 hours to ensure that Eu is entirely present in the +3 oxidation state in the glass. After the raw materials are fully melted, a fully molten glass is obtained.

[0042] Step 4: Preparation of luminescent glass: The above fully molten glass material is cast onto a copper plate at 480°C and held at this temperature for 1.5 hours. Then, it is cooled to room temperature with the furnace to obtain rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable luminescent glass, and its sample is marked as DTE2.

[0043] Example 3

[0044] The rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable light-emitting glass of this embodiment has raw materials and mass percentages shown in Table 1.

[0045] The preparation steps of the rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable light-emitting glass in this embodiment are as follows:

[0046] Step 1: Raw material weighing: Using P2O5, H3BO3, Al2O3, Li2CO3, K2CO3, Gd2O3, Dy2O3, Tb4O7, and Eu2O3 as raw materials, weigh them according to the mass percentage requirements in Table 1;

[0047] Step 2: Preparation of glass premix: Grind and mix the weighted glass raw materials and rare earth oxides to obtain a uniformly mixed glass premix;

[0048] Step 3: Preparation of fully molten glass: Transfer the uniformly mixed raw materials to a crucible and place it in a high-temperature furnace. Set the high-temperature furnace heating program to heat to 1200℃ at a heating rate of 8℃ / min, and hold at this temperature for 6.0 hours to ensure that Eu is entirely present in the +3 oxidation state in the glass. After the raw materials are fully melted, a fully molten glass is obtained.

[0049] Step 4: Annealing of the luminescent glass: The above fully molten glass material is cast onto a copper plate at 450°C and held at this temperature for 3.0 hours. Then it is cooled to room temperature in the furnace to obtain rare earth element Dy / Tb / Eu co-doped aluminum boron phosphate tunable luminescent glass, and its sample is marked as DTE3.

[0050] Example 4

[0051] This embodiment relates to the luminescence performance analysis of rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable luminescent glass, and the evaluation is carried out using luminescence spectrum.

[0052] The testing method is as follows:

[0053] Absorption spectra were detected using a UV-Vis-NIR spectrophotometer (PerkinElmer Lambda 950, USA) in the wavelength range of 300–750 nm. The results are as follows: Figure 1 As shown.

[0054] like Figure 1 As shown, the spectrum exhibits characteristics of Dy at different excitation wavelengths. 3+ Ions, Tb 3+ Ions and Eu 3+ The system exhibits strong green, yellow, and red light emission, and tuning these three colors effectively improves the emission color coordinates and color temperature. Furthermore, despite different excitation wavelengths, the overall luminescence intensity of the system increases significantly with the increase in the amount of rare-earth ions introduced. This indicates that the matrix glass has a strong rare-earth ion holding capacity, and no concentration quenching phenomenon occurs that leads to a decrease in luminescence intensity. Notably, under 386 nm excitation, Eu... 3+ The emission peak at 611nm is significantly stronger than that under excitation at 349nm and 364nm. Its high intensity is beneficial to improving the color temperature index of the emission and realizing warm white light emission.

[0055] Example 5

[0056] This embodiment involves CIE chromaticity coordinate analysis of rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable light-emitting glass, and the evaluation is performed using chromaticity coordinate diagrams.

[0057] The testing method is as follows:

[0058] The excitation, emission, and decay spectra of the samples were analyzed and tested using a fluorescence spectrometer (FLS 980, Edinburgh Instruments, UK), and the corresponding chromaticity coordinates were obtained using CIE1931 software based on the spectral data.

[0059] After calculation, the CIE chromaticity coordinates and color temperature of the DTE1-3 samples in Examples are as follows: Figure 2 As shown, under excitation at 350 and 364 nm, the chromatic coordinates of the glass sample systems in Examples DTE1-3 were all located in the yellow-green light region. The chromatic coordinates and color temperature did not change significantly with the excitation wavelength, with the CCT varying within a small range of 3583-3870 K. However, under excitation at 386 nm, the overall emission chromatic coordinates shifted towards the orange-yellow region, with a CCT of 2258-2512 K, indicating warm orange-yellow light. This corresponds to the emission spectrum under 386 nm excitation, which exhibits strong emission intensity in the red-orange band. Therefore, by adjusting the appropriate excitation wavelength, the chromatic coordinates of the glass can be adjusted from the yellow-green light region to the orange-red light region, expanding the luminescence range of the glass material, improving its luminescent performance, and enhancing its application in lighting under different conditions.

[0060] Example 6

[0061] This embodiment involves the analysis of fluorescence lifetime decay behavior of rare earth element Dy / Tb / Eu co-doped aluminum boron phosphate tunable light-emitting glass, and the fluorescence decay curve is used for evaluation.

[0062] The testing method is as follows:

[0063] The attenuation spectra of the samples were analyzed and tested using a fluorescence spectrometer (FLS 980, Edinburgh Instruments, UK).

[0064] The fluorescence lifetime curves of samples DTE1-3 in Examples were measured, and the results are shown in the appendix to the instruction manual. Figure 3 As shown. The calculated and fitted decay times for Examples DTE1-3 were 2.366, 2.266, and 2.171 ms, respectively. This decay time is related to the amount of rare earth ions introduced, indicating the presence of Dy. 3+ →Tb 3+ and Eu 3+ Energy transfer.

[0065] Example 7

[0066] Variations in ambient temperature have a significant impact on the luminescent properties of glass. Testing luminescent properties at different temperatures is crucial for determining whether the glass is suitable for practical applications. This embodiment involves the temperature-dependent luminescent performance analysis of a rare-earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable luminescent glass under 386 nm excitation, using temperature-dependent spectroscopy for evaluation.

[0067] The testing method is as follows:

[0068] Temperature-dependent spectroscopy of glass samples was performed using a full-function steady-state / transient fluorescence spectrometer (FLs 980). A 450W xenon lamp was used as the light source. The wavelength range was 300-700 nm with a step size of 1 nm. The temperature range was 300-500 K, and data was recorded every 50 K.

[0069] To evaluate the thermal stability of the material, the luminescence properties of the DTE3 sample in Example D at different temperatures were tested, and the results are as follows: Figure 4 As shown in the figure. Under 386 nm excitation, although the luminescence intensity of the glass decreases with increasing temperature, it still maintains more than 85% of its luminescence intensity even at 450 K, indicating that the luminescent glass has high thermal stability. Meanwhile, the fitting curve of the thermal quenching activation energy (Ea) is shown in the figure. Figure 4 As shown in the inset in (b), the slope of the fitted line, Ea, was measured to be 0.20361 eV, higher than existing research results. A higher activation energy corresponds to a lower non-radiative transition rate and better thermal stability, as can be seen from the fitted calculations. This further demonstrates that rare-earth element Dy / Tb / Eu co-doped aluminum borosilicate luminescent glass possesses excellent thermal stability.

[0070] In summary, the rare earth element Dy / Tb / Eu co-doped aluminum boron phosphate tunable light-emitting glass of the present invention can be applied to fields such as WLEDs, solid-state lasers, biological diagnostic detection, and temperature sensors, and has significant performance advantages over photoluminescent crystal materials in the prior art.

Claims

1. A rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable luminescent glass, characterized in that, It is made from the following raw materials in the indicated mass ratios: P2O5 50.0-60.0%, H3BO3 15.0-25.0%, Al2O3 10.0-20.0%, Li2CO3 1.0-6.0%, K2CO3 1.0-7.5%, Gd2O3 0.5-3.0%, rare earth oxide Dy2O3 0.5-1.0%, rare earth oxide Tb4O7 0.1-0.5%, and rare earth oxide Eu2O3 0.3-0.9%.

2. The rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable luminescent glass according to claim 1, characterized in that, The rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable light-emitting glass produces excellent warm white light emission under 386nm wavelength excitation, with color coordinates of (0.505, 0.425) and corresponding CCT of 2258K. The emitted color belongs to the warm white light hue.

3. A method for preparing a rare earth element Dy / Tb / Eu co-doped aluminum borophosphate tunable luminescent glass as described in claim 1 or 2, characterized in that, Includes the following steps: 1) After accurately weighing the raw materials, grind and mix them until they are evenly mixed to obtain glass premix; 2) Transfer the uniformly mixed glass premix to a crucible and place it in a high-temperature furnace; set the high-temperature furnace heating program and heat it to 1150-1250℃ at a heating rate of 5-10℃ / min, and hold it at this temperature for 5.0-7.0 hours so that Eu is entirely present in the glass in the +3 oxidation state. After the raw material is fully melted, a completely molten glass material is obtained. 3) The fully molten glass material is cast onto a copper plate at 400-480℃ and held at this temperature for 1.5-5.0 hours to eliminate the thermal stress inside the aluminum borosilicate glass. Then, it is cooled to room temperature with the furnace to obtain rare earth element Dy / Tb / Eu co-doped aluminum borosilicate tunable luminescent glass.

4. The application of a rare earth element Dy / Tb / Eu co-doped aluminum boron phosphate tunable light-emitting glass as described in claim 1 or 2 in WLED or solid-state lighting.

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