Eu < 3 + >-doped gallium aluminate red light-emitting glass as well as preparation method and application thereof

Abstract

The invention discloses Eu < 3 + >-doped gallium aluminate red light-emitting glass as well as a preparation method and application thereof, and relates to the technical field of light-emitting materials. The luminescent glass is prepared by adopting a melting-cooling method, and the preparation method comprises the following steps: weighing SiO2, B2O3, Na2O and Lu3AlGa3. 93O12. 0.07 Eu < 3 + > raw materials according to a ratio, grinding, mixing, melting at a high temperature to form a uniform glass melt, and cooling and molding to obtain the luminescent glass. The luminescent glass can stably emit light under the excitation of ultraviolet light and blue light with the wave band of 200-480 nm, has the characteristic of wide excitation range, and can be well matched with near ultraviolet or commercial blue light LED chips. Under excitation of 395 nm blue light, the luminescent glass emits red light mainly with the wavelength of 593 nm and 610 nm, and shows good color purity and color rendering performance along with 709 nm near-infrared emission components. Furthermore, the luminescent glass can still keep stable red light emission intensity under a high-temperature condition, presents a luminescent enhancement trend in a heating process, and shows good luminescent thermal stability. The luminescent glass is suitable for high-power solid-state illumination and related high-temperature photoelectric application fields.

Description

Technical Field

[0001] This invention relates to the field of luminescent materials technology, specifically to an Eu... 3+ Activated gallium aluminate red light emitting glass, its preparation method and application, applicable to high temperature, high power solid-state lighting and related optoelectronic devices. Background Technology

[0002] White light-emitting diodes (W-LEDs) are widely used in the lighting industry due to their advantages such as high efficiency, energy saving, environmental friendliness, reliability, long lifespan, and small size. Currently, the most widely used W-LED system in industrial applications typically employs InGaN blue LED chips combined with yellow phosphor Y3Al5O3. 12 :Ce 3+ (YAG:Ce) 3+ This approach aims to achieve white light output. However, this combination suffers from insufficient red light component in its spectral composition, often resulting in a low color rendering index (CRI) and a high correlated color temperature (CCT), making it difficult to meet the light quality requirements of high color rendering lighting applications. To improve the white light spectral structure and enhance luminous performance, introducing high-performance red light-emitting materials to compensate for long-wavelength radiation has become an important research direction. Currently, the red light-emitting materials used in W-LEDs mainly include nitride, sulfide, and fluoride systems. However, these materials generally suffer from insufficient thermal stability, demanding preparation conditions, or high environmental sensitivity under high-temperature packaging and long-term operating conditions, making it difficult to meet the engineering application requirements of high-power W-LEDs for long-term stable operation. In addition, existing packaging systems mostly adopt a composite structure of "phosphor / organic resin (such as epoxy resin, silicone)". Organic packaging materials are prone to thermal degradation or aging under multiple stresses such as heat, light and oxidation, which causes changes in scattering and absorption characteristics, resulting in a shift in the emission spectrum of the device. This manifests as unstable emission color and luminous efficiency decay, which seriously restricts the long-term reliable operation of high-power W-LEDs under high-temperature conditions.

[0003] To address the aforementioned issues, luminescent glass solutions employing inorganic matrices to achieve integrated light emission and encapsulation are gaining increasing attention. Compared to traditional phosphor-resin encapsulation, luminescent glass, by directly introducing phosphors into the glass matrix or using glass as a carrier for uniform dispersion, typically exhibits superior thermochemical stability, aging resistance, and structural designability. It also offers certain engineering advantages in molding, processing, and encapsulation adaptation. However, existing red luminescent glass systems still require further improvement in red light purity and high-temperature luminescence stability. Therefore, to meet the application requirements of high-power W-LEDs, there is an urgent need to develop a red luminescent glass material that can be directly melt-molded, possesses excellent red light performance, and maintains stable luminescence performance under high-temperature conditions. Summary of the Invention

[0004] The purpose of this invention is to provide a Eu 3+ Doped gallium aluminate red-emitting glass, its preparation method, and its applications are disclosed. This emitting glass maintains stable red light emission performance even under elevated temperatures, thus improving the material's luminescence stability at high temperatures. The preparation method is simple and can be fabricated using a melt-forming process, making it suitable for large-scale production. The emitting glass can be applied to high-power white LEDs and other optoelectronic devices, helping to alleviate problems such as red light attenuation and unstable emission color under high-temperature operating conditions.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: The present invention provides an Eu... 3+ The doped gallium aluminate red-emitting glass is characterized by the introduction of Lu3AlGa, which has negative thermal quenching properties for luminescence, into an inorganic transparent glass matrix. 4-x O 12 :xEu 3+ (0.001≤x≤0.30,LAGO:Eu 3+ A red phosphor is used to construct an integrated "light emission-encapsulation" red light-emitting glass system. Under excitation by ultraviolet or blue light in the 200–480 nm wavelength range, this light-emitting glass can produce red light emission in the 593–700 nm range, with a narrow emission spectrum and high color purity. This allows for good spectral matching with commercial blue LED chips, meeting the red light compensation requirements of white light devices. Furthermore, this red light-emitting glass can maintain a red light emission intensity no lower than room temperature even under heated conditions, demonstrating good high-temperature luminescence stability.

[0006] A Eu 3+ The preparation method of doped gallium aluminate red light emitting glass includes the following steps: (1) weighing compound raw materials containing Lu, Al, Ga and Eu in molar ratio, mixing and grinding the raw materials to obtain a uniform precursor mixture; (2) Place the precursor mixture obtained in step (1) in an air atmosphere and carry out a high-temperature reaction at 1300–1550 °C for 3–12 hours to obtain the calcined product. Grind the product into powder to obtain the precursor luminescent material. (3) The compounds of Si, B and Na are used as glass matrix raw materials and mixed with the precursor luminescent material obtained in step (2) at a mass fraction of 0.01%–5% and stirred for 0.5–24 hours to obtain luminescent glass precursor raw materials; (4) The light-emitting glass precursor material obtained in step (3) is melted in air at 600–1600 °C and kept at that temperature for 1–60 minutes to fully melt the glass matrix and disperse it evenly with the phosphor to form a uniform glass melt. (5) The glass melt obtained in step (4) is poured or pressed onto a copper plate at 400 °C and kept at that temperature for 5 hours to eliminate internal stress. After cooling, red light luminescent glass is obtained.

[0007] In a further embodiment of the present invention: The lutetium-containing compound is at least one of lutetium carbonate, lutetium oxide, or lutetium hydroxide; The aluminum-containing compound is at least one of aluminum oxide, aluminum hydroxide, aluminum nitrate, or aluminum carbonate; The gallium-containing compound is at least one of gallium oxide, gallium hydroxide, gallium nitrate, or gallium carbonate; The europium-containing compound is at least one of europium nitrate or europium oxide; The silicon-containing compound is at least one of silicon dioxide, sodium silicate, or potassium silicate; The boron-containing compound is at least one of boron trioxide, boric acid, or borax; The sodium-containing compound is at least one of sodium oxide, sodium carbonate, or sodium nitrate.

[0008] The above-mentioned raw materials can also be prepared using other equivalent compounds or existing technical means.

[0009] The beneficial effects of this invention are as follows: The luminescent glass exhibits negative thermal quenching luminescence behavior under high temperature conditions. The luminescence intensity at 480 K and 500 K reaches 119.58% and 116.38% of that at room temperature (300 K), respectively. This indicates that the material can still maintain a high red light emission intensity in a high temperature environment, which is beneficial to improving its high temperature luminescence stability. The preparation method provided by this invention has a simple process flow, readily available raw materials, low synthesis cost, and is suitable for large-scale industrial production.

[0010] The light-emitting device constructed based on this light-emitting glass can maintain stable red light output under high power and high temperature operating environments, and has good thermal stability and reliability. It can be applied to high-power white LEDs, high-temperature solid-state lighting and related light source fields. Attached Figure Description

[0011] Figure 1 The glass prepared in Example 1 of this invention and its doping with 4 wt% Lu3AlGa 3.93 O 12 0.07Eu 3+ Photographs of the back-illuminated glass under white light and 395 nm blue light; Figure 2 This is the excitation spectrum at 593 nm monitored by the luminescent glass in Embodiment 1 of the present invention; Figure 3 This is the emission spectrum of the luminescent glass in Embodiment 1 of the present invention under 395 nm excitation; Figure 4 This is a stereoscopic view of the emission spectrum of the luminescent glass in Embodiment 1 of the present invention in the range of 300-500 K; Figure 5 This is a planar image of the emission spectrum of the luminescent glass in Embodiment 1 of the present invention in the range of 300-500 K; Detailed Implementation The technical solution of the present invention will be further described below with reference to embodiments thereof. It should be understood that the embodiments described below are merely one specific embodiment of the present invention, used to illustrate the technical concept of the present invention, and not to limit the scope of protection of the present invention. All equivalent changes or substitutions made based on the technical solution of the present invention without creative effort should fall within the scope of protection of the present invention.

[0012] All reagents used in the following Example 1 were commercially available, and the commercially available reagents were of analytical grade or higher purity.

[0013] According to the chemical formula Lu3AlGa 3.93 O 12 0.07Eu 3+ The stoichiometric ratio was such that the amount of the target product was 0.004 mol. 2.3876 g of lutetium oxide, 0.2039 g of aluminum oxide, 1.4732 g of gallium oxide, and 0.0493 g of europium oxide were accurately weighed, ground and mixed, and then placed in an alumina crucible. The mixture was sintered at 1500 °C for 12 hours in an air atmosphere in a muffle furnace, cooled to room temperature with the furnace, and then ground into powder to obtain Lu3AlGa. 3.93 O 12 0.07Eu 3+ Precursor luminescent powder. The sintering temperature and time can be adjusted within a reasonable range according to equipment conditions to ensure that the precursor powder reacts completely and forms a stable phase structure.

[0014] Subsequently, a sodium borosilicate glass matrix was prepared according to the following mass percentages: SiO2 75%, B2O3 20%, and Na2O 5%, with a total glass raw material weight of 3 g. The prepared Lu3AlGa... 3.93 O 12 0.07Eu 3+ The precursor powder was added at 4 wt% of the glass matrix. The mixed powder was placed in a 100 mL beaker, and an appropriate amount of pure water was added. The mixture was stirred at approximately 400 r·min⁻¹ for 12 h to ensure uniform dispersion of the luminescent powder in the glass matrix. The mixture was then allowed to stand for 12 h, the supernatant was discarded, and the mixture was dried in a 60 ℃ oven for 12 h to ensure complete evaporation of moisture from the mixed powder.

[0015] The mixed powder was placed in an alumina crucible and sintered at 900 °C for 5 minutes in air. Immediately after sintering, the crucible was removed, and the molten glass was poured onto a preheated brass mold (400 °C). The molded sample was then pressed into shape using a copper plate. The formed sample was held at 400 °C for 5 hours to relieve internal stress, and then allowed to cool naturally to room temperature, thus obtaining Eu. 3+ Doped gallium aluminate red light-emitting glass.

[0016] Test method: Under white light and 395 nm blue light excitation conditions, a digital camera (e.g., SONY ILCE-A7R4) was used to observe the glass sample and its 4 wt% Lu3AlGa doped glass. 3.93 O 12 0.07Eu 3+ The light-emitting glass was photographed, as shown in Figure 1.

[0017] The luminescent glass prepared in Example 1 was characterized using a fluorescence spectrometer (FLS 1000, Edinburgh Instruments, UK). Its excitation spectrum was obtained under emission monitoring conditions of 593 nm. Figure 2 The results showed that the sample exhibited a broad and strong excitation band in the 200–480 nm range, indicating that it could be effectively excited by ultraviolet and blue light chips and had good matching capability with commercial excitation sources. Its emission spectrum was obtained under the optimal excitation wavelength of 395 nm. Figure 3 The results show that the material produces strong red light emission under blue light excitation, with the emission range mainly concentrated between 590 and 710 nm, and the main emission peak located at 593 nm, which is attributed to Eu. 3+ of 5 D0→ 7 F1 and 5 D0→ 7 The F2 transition exhibits excellent red light emission performance and high color purity.

[0018] The luminescence of the luminescent glass was tested using an FLS 1000 fluorescence spectrometer (Edinburgh Instruments) combined with a variable-temperature testing system (Oxford Optistat DN2) with a 450 W xenon lamp as the excitation source in the wavelength range of 500–800 nm. The thermal stability of the luminescence was evaluated within the temperature range of 300–500 K, with luminescence spectra recorded every 20 K. The results show that the luminescence intensity of the luminescent glass did not significantly decrease with increasing temperature; instead, it remained stable and even showed an increasing trend in the mid-to-high temperature range, demonstrating good thermal stability and resistance to thermal quenching.

[0019] In summary, this luminescent glass not only possesses high color purity and a wide excitation band, but also exhibits stable and increasingly enhanced red light emission performance under high-temperature conditions, making it a potential application in high-power white LEDs, high-temperature solid-state lighting, and related light sources.

[0020] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A Eu 3+ Doped gallium aluminate red light-emitting glass, characterized in that, The luminescent glass comprises an inorganic transparent glass matrix and a red phosphor dispersed in the glass matrix, wherein the red phosphor is Lu3AlGa 4-x O 12 :xEu 3+ (0.001≤x≤0.30); Under ultraviolet or blue light excitation in the 200–480 nm band, the luminescent glass can produce red light emission in the range of 593–700 nm.

2. The luminescent glass according to claim 1, characterized in that, The luminescent glass can maintain a red light emission intensity no lower than room temperature even when heated to 480 K–500 K.

3. The luminescent glass according to claim 1, characterized in that, The inorganic transparent glass matrix is ​​a sodium borosilicate glass matrix, and the sodium borosilicate glass matrix includes SiO2, B2O3 and Na2O.

4. The luminescent glass according to claim 1, characterized in that, The red phosphor has a mass fraction of 0.01 wt%–5 wt% in the luminescent glass.

5. A Eu 3+ A method for preparing doped gallium aluminate red-emitting glass, characterized in that, Includes the following steps: (1) Mix the compound raw materials containing lutetium, aluminum, gallium and europium according to the stoichiometric ratio, grind them and then carry out a high-temperature reaction in air at 1000–1600 °C to obtain the calcined product, and grind the calcined product into powder to obtain the precursor light-emitting material; (2) The precursor luminescent material is mixed with the glass matrix raw material and uniformly dispersed to obtain the luminescent glass precursor material; (3) The luminescent glass precursor material is melted into a glass melt in an air atmosphere, and then formed and annealed to obtain red luminescent glass.

6. The Eu as described in any one of claims 1–4 3+ Gallium-doped aluminate red light-emitting glass is used in white LEDs, high-power solid-state lighting, or related light source devices.

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