A rare earth-based gallate high-entropy red fluorescent ceramic material and a preparation method thereof

Abstract

This invention relates to the field of fluorescent ceramics technology, specifically to a rare-earth-based gallium salt high-entropy red fluorescent ceramic material and its preparation method. The high-entropy fluorescent ceramic material of this invention has a single-phase garnet structure and can achieve efficient red light emission under blue light excitation. Its general chemical formula is: RE3Ga5O. 12 :xLn 3+ RE is a combination of at least five rare earth elements, namely Y, La, Nd, Sm, Eu, Gd, Ho, Er, Yb, and Lu, in an equimolar or near-equimolar ratio; Ln 3+ For Nd 3+ 、Sm 3+ Eu 3+ 、Tb 3+ Tm 3+ At least one activator ion in the composition; x is the molar percentage of the activator ion, 0.01 ≤ x ≤ 0.15. (Compared with single-component Y3Ga5O) 12 Eu 3+ Compared to other methods, the luminescence quantum yield of the high-entropy fluorescent ceramic material of this invention is increased from 35.3% to 67.8%, the luminescence intensity retention at 423K is improved from 76.6% to 89.1%, and the fluorescence lifetime is extended from 1.35 ms to 1.56 ms. Through high-entropy engineering design, the luminescence efficiency and thermal stability of the high-entropy fluorescent ceramic material of this invention are significantly improved, showing broad application prospects in the field of solid-state lighting.

Description

Technical Field

[0001] This invention relates to the field of fluorescent ceramics technology, specifically to a rare-earth-based gallium salt high-entropy red fluorescent ceramic material and its preparation method. Background Technology

[0002] With the development of solid-state lighting, white LEDs have been widely used due to their advantages such as energy saving, environmental protection, and long lifespan. Currently, the mainstream solution is to use blue InGaN chips to excite YAG:Ce. 3+ Yellow phosphors are used, but the resulting white light has a low color rendering index due to insufficient red light content, making it difficult to meet the requirements of high-quality lighting. Therefore, the development of high-performance red phosphors that match blue light chips has become a research hotspot.

[0003] YAG:Eu 3+ As a classic red fluorescent material, garnet has advantages such as stable structure and mature synthesis process. However, its luminescence quantum yield is low and it suffers from problems such as concentration quenching and poor thermal stability, which limit its practical application. Other red materials such as nitrides and sulfur oxides have improved some properties, but they generally suffer from defects such as harsh synthesis conditions, high cost or insufficient chemical stability.

[0004] To overcome the performance bottlenecks of existing red fluorescent materials, it is urgent to explore new material systems and design strategies. This invention proposes a novel rare-earth-based gallate high-entropy fluorescent ceramic material, aiming to optimize luminous efficiency and thermal stability through high-entropy engineering, thereby meeting the urgent need for high-performance red light materials in the field of solid-state lighting. Summary of the Invention

[0005] The purpose of this invention is to provide a rare-earth-based gallium salt high-entropy red fluorescent ceramic material and its preparation method, in order to solve the problems of traditional YAG:Eu 3+ The problems include low fluorescence quantum yield and poor thermal stability.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a rare-earth-based gallium salt high-entropy fluorescent ceramic material, the chemical formula of which is as follows: (RE1RE2RE3RE4RE5)3Ga5O 12 :xLn 3+ ; Among them, RE1, RE2, RE3, RE4, and RE5 are five different rare earth elements, each independently selected from one of Y, La, Nd, Sm, Eu, Gd, Ho, Er, Yb, and Lu, and the molar ratio of the five rare earth elements is equimolar or nearly equimolar; Ln 3+ Rare earth ions, selected from Nd, are activators. 3+ 、Sm 3+Eu 3+ 、Tb 3+ Tm 3+ One or more of the following, where x is the molar percentage of activator ions relative to the total number of RE sites, and 0.01 ≤ x ≤ 0.15.

[0008] Furthermore, in the ceramic material, the five rare earth elements are uniformly distributed at the same lattice position in the garnet lattice, forming a single-phase solid solution structure with high configurational entropy.

[0009] Furthermore, the ceramic material is exemplary selected from any of the following: (Y 0.2 La 0.2 Gd 0.2 Yb 0.2 Lu 0.2 )3Ga5O 12 :xEu 3+ (Y 0.2 La 0.2 Nd 0.2 Eu 0.2 Gd 0.2 )3Ga5O 12 :xEu 3+ (Y 0.2 La 0.2 Sm 0.2 Eu 0.2 Lu 0.2 )3Ga5O 12 :xEu 3+ Furthermore, the rare-earth-based gallium salt high-entropy fluorescent ceramic material has a garnet structure and a space group of Ia-3d.

[0010] Furthermore, the rare-earth-based gallium salt high-entropy fluorescent ceramic material exhibits strong absorption in the blue light band (440~470nm) and strong characteristic emission in the red light band (590~630nm), corresponding to the activator ions. 5 D0→ 7 F2 characteristic transition.

[0011] Furthermore, the luminescence quantum yield (QY) of the rare-earth-based gallate high-entropy fluorescent ceramic material reaches more than 50%, preferably more than 67.8%.

[0012] Furthermore, the luminescence intensity of the rare earth-based gallate high-entropy fluorescent ceramic material at 423K (150℃) remains at more than 70% of the initial intensity, preferably more than 73%; and even more preferably more than 89%.

[0013] Secondly, the present invention provides a method for preparing a rare-earth-based gallium salt high-entropy fluorescent ceramic material, the method comprising the following steps: (1) Raw material mixing: The RE source, Ga source and activator source are mixed and ball-milled with ethanol as the medium to obtain a uniform slurry; the RE source is an oxide of five different rare earth elements and the activator source is an oxide of activator rare earth ions; (2) First calcination: The slurry obtained in step (1) is dried, sieved, pressed into shape to obtain a green body, and the green body is calcined for the first time to obtain a pre-calcined product; (3) Secondary ball milling: After crushing the pre-calcined product obtained in step (2), it is ball milled again with ethanol as the medium to obtain a secondary slurry; (4) Second calcination: The secondary slurry obtained in step (3) is dried, sieved, pressed into a green body, and then calcined and crushed to obtain rare earth-based gallium salt high-entropy fluorescent ceramic material.

[0014] Further, in step (1), the RE source is selected from five of the following: yttrium oxide (Y2O3), lanthanum oxide (La2O3), neodymium oxide (Nd2O3), samarium oxide (Sm2O3), europium oxide (Eu2O3), gadolinium oxide (Gd2O3), holmium oxide (Ho2O3), erbium oxide (Er2O3), ytterbium oxide (Yb2O3), and lutetium oxide (Lu2O3); the Ga source is gallium oxide (Ga2O3); and the activator source is one or more of the following: neodymium oxide (Nd2O3), samarium oxide (Sm2O3), europium oxide (Eu2O3), terbium oxide (Tb2O3), and thulium oxide (Tm2O3).

[0015] Furthermore, in step (1), the molar ratio of the RE source, Ga source, and activator source satisfies the chemical formula (RE1RE2RE3RE4RE5)3Ga5O 12 :xLn 3+ The measurement ratio.

[0016] Further, in step (1), the ball mill speed is 350~450 rpm and the ball milling time is 4~10 h; preferably, the ball mill adopts an intermittent working mode, working for 5 min and then pausing for 1 min, rotating in both directions.

[0017] Furthermore, in step (1), the amount of ethanol used should be such that it submerges the zirconium oxide balls and raw materials in the milling jar.

[0018] Furthermore, in step (2), the drying temperature is 60~80℃ and the drying time is 10~24h; the sieve mesh size used for sieving is 200~400 mesh.

[0019] Furthermore, in step (2), the pressing pressure is 5~10MPa, the pressing time is 20~50 seconds, and the diameter of the pressed blank is 10~20mm.

[0020] Furthermore, in step (2), the temperature of the first calcination is 1400~1550℃, the holding time is 2~6h, and the heating rate is 5~10℃ / min.

[0021] Furthermore, in step (3), the rotation speed of the secondary ball mill is 350~450 rpm, and the ball milling time is 4~10 h; preferably, the ball mill adopts an intermittent working mode.

[0022] Furthermore, in step (4), the drying temperature is 60~80℃ and the drying time is 10~24h; the sieve mesh size used for sieving is 200~400 mesh.

[0023] Furthermore, in step (4), the pressing pressure is 5~15MPa, the pressing time is 20~50 seconds, and the diameter of the pressed blank is 10~20mm.

[0024] Furthermore, in step (4), the temperature of the second calcination is 1500~1650℃, the holding time is 4~10h, and the heating rate is 5~10℃ / min.

[0025] As a preferred embodiment of the present invention, the preparation method of the rare-earth-based gallium salt high-entropy fluorescent ceramic material specifically includes the following steps: (1) Weigh out five rare earth oxides, gallium oxide and activator oxide according to stoichiometric ratio, place them in a ball mill jar, use ethanol as medium, and ball mill at 350~450 rpm for 4~10 h to obtain a uniform slurry; (2) Dry the slurry obtained in step (1) at 60~80℃ for 10~24h, pass it through a 200~400 mesh sieve to obtain mixed powder; press the mixed powder into a blank with a diameter of 10~20mm under a pressure of 5~10MPa for 20~50s. (3) Place the billet obtained in step (2) in a muffle furnace, heat it to 1400-1550℃ at 5-10℃ / min, keep it at the temperature for 2-6 hours, and cool it with the furnace to obtain the pre-fired product; (4) After crushing the pre-calcined product obtained in step (3), place it in a ball mill jar and ball mill it for 4 to 10 hours at a speed of 350 to 450 rpm using ethanol as the medium to obtain a secondary slurry. (5) Dry the secondary slurry obtained in step (4) at 60~80℃ for 10~24h, pass it through a 200~400 mesh sieve to obtain composite powder; press the composite powder into a blank with a diameter of 10~20mm under a pressure of 5~15MPa for 20~50s. (6) Place the blank obtained in step (5) in a muffle furnace, heat it to 1500~1650℃ at 5~10℃ / min, keep it at 4~10h, cool it with the furnace, crush it, and obtain rare earth-based gallium salt high-entropy fluorescent ceramic material.

[0026] Thirdly, the present invention also provides applications of the rare earth-based gallium salt high-entropy fluorescent ceramic material in solid-state lighting, display devices, anti-counterfeiting labels, optical temperature measurement and other fields.

[0027] The beneficial effects of this invention are: This invention is the first to introduce the concept of high-entropy engineering into the design and preparation of gallate fluorescent materials. By dissolving various rare earth elements such as La, Gd, Y, Yb, and Lu in equimolar proportions into the same lattice position, a high-entropy ceramic phosphor with a single-phase garnet structure was successfully synthesized.

[0028] 1. The high-entropy design of this invention significantly improves the luminescence quantum yield of the material, using Eu... 3+ When used as an activator, the high-entropy ceramic phosphor exhibits extremely strong red light emission at 590 nm under 456 nm blue light excitation, corresponding to Eu... 3+ of 5 D0→ 7 The F2 characteristic transition, with quantum yield (QY) significantly increasing with increasing cation number, from a single component (Y3Ga5O) 12 Eu 3+ The percentage of Y increased to 35.3% in the high-entropy component [(Y 0.2 La 0.2 Gd 0.2 Yb 0.2 Lu 0.2 )3Ga5O 12 Eu 3+ The quantum yield was 49.7%, and through subsequent heat treatment optimization, the quantum yield was further improved to 67.8%. Through band structure calculation, the high entropy effect formed a localized acceptor energy state near the top of the valence band (about 2.2 eV) in the band gap, and constructed a dual-channel mechanism of "electron capture-directed injection", which effectively promoted the radiative recombination of charge carriers.

[0029] 2. Tanabe-Sugano plot analysis confirmed that the high-entropy design placed the activator ions in a weak lattice field environment (Dq / B≈2.28). By adjusting the octahedral field strength (the field strength parameter decreased from 3.21 to 2.94), the optimization of the lattice field environment significantly suppressed phonon-assisted nonradiative transitions. Synchrotron radiation XPS tests showed that the occupancy rate of the O 1s orbital in the high-entropy material increased by 8.3%, indicating that the oxygen coordination environment of the lattice was optimized and the lattice integrity was improved. This optimization of the lattice field environment effectively reduced the dissipation of excitation energy in lattice vibrations, allowing more energy to be released in the form of radiation, thereby significantly improving the luminescence efficiency.

[0030] 3. Temperature dependence tests show that the high-entropy gallium salt system of this invention still retains 89.1% of its initial luminescence intensity at 423K (150℃), while the single-component Y3Ga5O 12 The system retains only 76.6% of its original properties; the excellent thermal and chemical stability of high-entropy materials can meet the long-term service performance requirements of solid-state lighting devices.

[0031] 4. The material after high entropy enhancement exhibits an ultra-long luminescence lifetime of 1.56 ms under visible light excitation (440 nm), while the single-component system has a lifetime of only 1.35 ms. The extended luminescence lifetime indicates that the high entropy structure effectively suppresses non-radiative recombination channels, providing a longer relaxation time for radiative transitions of the excitation energy, which is beneficial to improving luminescence efficiency.

[0032] 5. This invention uses a high-temperature solid-state synthesis method, which is simple to prepare and highly compatible with traditional phosphor production processes. It requires no complex equipment, is easy to operate, and has low cost, making it suitable for large-scale industrial production. Through the optimization of the secondary ball milling and secondary calcination processes, the purity and crystallinity of the material are effectively improved, ensuring the stability and repeatability of the product performance.

[0033] In summary, the rare-earth-based gallate high-entropy fluorescent ceramic material provided by this invention achieves a synergistic improvement in luminescence quantum yield, thermal stability, and luminescence lifetime through the innovative application of the high-entropy engineering concept, and has broad application prospects in fields such as solid-state lighting and display devices. Attached Figure Description

[0034] Figure 1 The (Y) prepared in Example 1 of this invention 0.2 La 0.2 Gd 0.2 Yb 0.2 Lu 0.2 )3Ga5O 12 Eu 3+ The X-ray diffraction (XRD) pattern of the high-entropy fluorescent ceramic material reveals its phase structure and crystallinity.

[0035] Figure 2 The (Y) prepared in Example 1 of this invention 0.2 La 0.2 Gd 0.2 Yb 0.2 Lu 0.2 )3Ga5O 12 Eu 3+ Excitation spectra of high-entropy fluorescent ceramic materials.

[0036] Figure 3 The (Y) prepared in Example 1 of this invention 0.2 La 0.2 Gd 0.2 Yb 0.2 Lu 0.2 )3Ga5O 12 Eu 3+ Luminescence decay curve of high-entropy fluorescent ceramic material.

[0037] Figure 4 The (Y) prepared in Example 1 of this invention 0.2 La 0.2 Gd 0.2 Yb 0.2 Lu 0.2 )3Ga5O 12 Eu 3+ Temperature-dependent emission spectra of high-entropy fluorescent ceramic materials.

[0038] Figure 5 The (Y) prepared in Example 1 of this invention 0.2 La 0.2 Gd 0.2 Yb 0.2 Lu 0.2 )3Ga5O 12 Eu 3+ Luminescent quantum yield of high-entropy fluorescent ceramic materials and single-component Y3Ga5O 12 Eu 3+ The comparison chart. Detailed Implementation

[0039] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention.

[0040] This invention introduces multiple rare earth elements such as La, Gd, Y, Yb, and Lu into the same lattice position of the gallate garnet structure in an equimolar ratio, forming a high-entropy stable single-phase solid solution, and uses Eu... 3+ 、Sm 3+ 、Tb 3+Using rare earth ions as activators, the study found that the high-entropy design not only maintained the integrity of the garnet structure, but also optimized the lattice field environment through multi-element synergistic effects, significantly suppressed non-radiative transitions, and unexpectedly greatly improved the material's luminescence quantum yield and thermal stability, achieving efficient matching with the chip.

[0041] Example 1 This embodiment provides a rare-earth-based gallium salt high-entropy fluorescent ceramic material with the chemical formula (Y). 0.2 La 0.2 Gd 0.2 Yb 0.2 Lu 0.2 )3Ga5O 12 Eu 3+ (Eu) 3+ (Doping molar percentage is 9%), the preparation method includes the following steps: (1) Weighing and mixing raw materials Five rare earth oxides, namely yttrium oxide (Y₂O₃, purity 99.99%), lanthanum oxide (La₂O₃, purity 99.99%), gadolinium oxide (Gd₂O₃, purity 99.99%), ytterbium oxide (Yb₂O₃, purity 99.99%), lutetium oxide (Lu₂O₃, purity 99.99%), gallium oxide (Ga₂O₃, purity 99.99%), and europium oxide (Eu₂O₃, purity 99.99%), were weighed according to stoichiometric ratios.

[0042] Place the above raw materials in a ball mill jar, add anhydrous ethanol as the ball milling medium, and the amount of ethanol should be enough to submerge the zirconia balls and raw materials; ball mill in a planetary ball mill at 400 rpm for 6 hours, using an intermittent working mode (5 minutes of operation, 1 minute of rest, alternating forward and reverse rotation) to obtain a uniform slurry.

[0043] (2) First drying and tableting The slurry obtained in step (1) was placed in an oven and dried at 70°C for 12 hours. It was then passed through a 300-mesh sieve to obtain a mixed powder. An appropriate amount of the mixed powder was placed in a stainless steel mold and pressed under 8MPa pressure for 20 seconds to obtain a cylindrical blank with a diameter of 15mm.

[0044] (3) First calcination The blank obtained in step (2) was placed in a corundum crucible and placed in a muffle furnace. It was heated to 1450°C at a heating rate of 8°C / min and held for 4 hours. It was then cooled to room temperature with the furnace to obtain the pre-fired product.

[0045] (4) Secondary ball milling After crushing the pre-calcined product obtained in step (3), place it in a ball mill jar, add anhydrous ethanol as the ball milling medium, and ball mill it in a planetary ball mill at 400 rpm for 6 hours (5 minutes of operation, 1 minute of rest, alternating forward and reverse rotation) to obtain a secondary slurry.

[0046] (5) Second drying and tableting The secondary slurry obtained in step (4) is placed in an oven and dried at 70°C for 12 hours. It is then passed through a 300-mesh sieve to obtain composite powder. An appropriate amount of composite powder is placed in a stainless steel mold and pressed under 10MPa pressure for 30 seconds to obtain a cylindrical blank with a diameter of 15mm.

[0047] (6) Second calcination The blank obtained in step (5) was placed in a corundum crucible, placed in a muffle furnace, heated to 1580℃ at a heating rate of 8℃ / min, held for 6 hours, cooled to room temperature with the furnace, and crushed to obtain (Y 0.2 La 0.2 Gd 0.2 Yb 0.2 Lu 0.2 )3Ga5O 12 Eu 3+ High-entropy fluorescent ceramic materials.

[0048] Performance characterization: (1) Phase analysis: The X-ray diffraction (XRD) pattern of the high-entropy fluorescent ceramic material prepared in this embodiment is as follows: Figure 1 As shown in the figure. The results indicate that the composite oxide retains the single-phase garnet structure with the Ia-3d space group configuration after high-temperature solid-state reaction, and no impurity phase peaks appear, indicating that a high-entropy solid solution has been successfully synthesized.

[0049] (2) Spectral performance: The excitation spectrum (monitoring wavelength 590 nm) of the high-entropy fluorescent ceramic material prepared in this embodiment is as follows: Figure 2 As shown in the figure, the material exhibits strong absorption in the blue light region (450~470nm), which perfectly matches the emission wavelength of commercial InGaN blue light chips.

[0050] (3) Luminescence lifetime: The luminescence decay curve of the high-entropy fluorescent ceramic material prepared in this embodiment is as follows: Figure 3 As shown. Through single-exponential fitting, the fluorescence lifetime of the material was found to be 1.56 ms, which is significantly higher than that of the single-component Y3Ga5O. 12 Eu 3+ The luminescence lifetime of 1.35 ms indicates that the high-entropy structure effectively suppresses the non-radiative recombination channel, which is beneficial to improving luminescence efficiency.

[0051] (4) Thermal stability: The temperature-dependent emission spectrum (temperature range 298~523K) of the high-entropy fluorescent ceramic material prepared in this embodiment is as follows: Figure 4 As shown in the figure. The results indicate that the luminescence intensity gradually decreases with increasing temperature, but the decrease is significantly smaller than that of the single-component system; at 423 K (150 °C), the material still retains 89.1% of its initial luminescence intensity, while the single-component Y3Ga5O... 12 Eu 3+ The system retains only 76.6% of its original properties at the same temperature.

[0052] (5) Quantum yield: The luminescence quantum yield of the high-entropy fluorescent ceramic material prepared in this embodiment is similar to that of the single-component Y3Ga5O 12 Eu 3+ For example Figure 5 As shown in the figure. It can be seen from the figure that the single component Y3Ga5O 12 Eu 3+ The quantum yield of the original material was only 35.3%, while the quantum yield of the high-entropy material (single calcination) in this embodiment reached 49.7%; after subsequent heat treatment process optimization (secondary calcination), the quantum yield was further increased to 67.8%.

[0053] Example 2 This embodiment provides a rare-earth-based gallium salt high-entropy fluorescent ceramic material with the chemical formula (Y). 0.2 La 0.2 Nd 0.2 Eu 0.2 Gd 0.2 )3Ga5O 12 Eu 3+ (Eu) 3+ The doping molar percentage is 9%). The preparation method is the same as in Example 1, except that the rare earth oxides in step (1) are adjusted to five types: yttrium oxide, lanthanum oxide, neodymium oxide, europium oxide, and gadolinium oxide.

[0054] Performance characterization: The high-entropy fluorescent ceramic material prepared in this embodiment also has a single-phase garnet structure with space group Ia-3d. Under 456 nm blue light excitation, the material exhibits strong red light emission at 590 nm, with a luminescence quantum yield of 48.2%, and the luminescence intensity at 423 K remains at 87.5% of the initial intensity.

[0055] Example 3 This embodiment provides a rare-earth-based gallium salt high-entropy fluorescent ceramic material with the chemical formula (Y). 0.2 La 0.2 Sm 0.2 Eu 0.2 Lu 0.2 )3Ga5O12 Eu 3+ (Eu) 3+ The doping molar percentage is 9%). The preparation method is the same as in Example 1, except that the rare earth oxides in step (1) are adjusted to five types: yttrium oxide, lanthanum oxide, samarium oxide, europium oxide, and lutetium oxide.

[0056] Performance characterization: The high-entropy fluorescent ceramic material prepared in this embodiment has a single-phase garnet structure. Under 456 nm blue light excitation, the material exhibits strong red light emission at 590 nm. The luminescence quantum yield reaches 47.5%, and the luminescence intensity at 423 K remains at 86.9% of the initial intensity.

[0057] Example 4 This embodiment examines Eu 3+ The effect of doping concentration on luminescence performance, with (Y) 0.2 La 0.2 Gd 0.2 Yb 0.2 Lu 0.2 )3Ga5O 12 Eu was prepared using the matrix. 3+ A series of samples with doping molar percentages of 1%, 3%, 5%, 7%, 9%, 11%, and 13% were prepared using the same method as in Example 1.

[0058] Performance characterization: Luminescence intensity tests show that, with Eu 3+ With increasing doping concentration, the luminescence intensity initially increases and then decreases, with the optimal doping concentration being 9%. When the doping concentration exceeds 15%, concentration quenching occurs, which is due to Eu... 3+ This is caused by energy transfer and cross-relaxation between ions.

[0059] Example 5 This embodiment provides a rare-earth-based gallium salt high-entropy fluorescent ceramic material with the chemical formula (Y). 0.2 La 0.2 Gd 0.2 Yb 0.2 Lu 0.2 )3Ga5O 12 :Sm 3+ (Sm) 3+ (The doping molar percentage is 9%), and the preparation method is the same as in Example 1.

[0060] Performance characterization: The high-entropy fluorescent ceramic material prepared in this embodiment has a single-phase garnet structure. Under 456 nm blue light excitation, the material exhibits strong red light emission at 605 nm. The luminescence quantum yield reaches 35.6%, and the luminescence intensity at 423 K remains at 78% of the initial intensity. Compared to Eu... 3+ Sm 3+ The dominant luminescence has shifted.

[0061] Comparative Example 1 This comparative example provides a single-component fluorescent ceramic material with the chemical formula Y3Ga5O. 12 Eu 3+ (Eu) 3+ The doping molar percentage is 9%), and the preparation method is the same as in Example 1, except that only yttrium oxide is used as the rare earth oxide in step (1).

[0062] Performance characterization: Y3Ga5O prepared in this comparative example 12 Eu 3+ The material also has a garnet structure. Under 456 nm blue light excitation, the material exhibits red light emission at 590 nm, but the luminescence intensity is significantly weaker than that of Example 1; the luminescence quantum yield is only 35.3%, the luminescence intensity at 423 K remains at 76.6% of the initial intensity, and the fluorescence lifetime is 1.35 ms; all performance indicators are significantly lower than those of the high-entropy material of Example 1, and the performance comparison is shown in the table below.

[0063] Table 1 Summary of key performance parameters of Examples 1-3 and Comparative Example 1

[0064] As can be seen from the data in Table 1, the high-entropy gallate fluorescent ceramic material of the present invention is significantly superior to traditional single-component materials in terms of quantum yield, thermal stability and fluorescence lifetime, which confirms the unique advantages of high-entropy engineering in optimizing the performance of fluorescent materials.

[0065] To further elucidate the optimization mechanism of the high-entropy effect on luminescence performance, in-depth theoretical and experimental analysis was conducted on the material of Example 1: (1) Band structure analysis: Density functional theory (DFT) calculations show that the high entropy effect in the band gap forms localized acceptor states near the top of the valence band, constructing a dual-channel mechanism of "electron capture-directed injection". This unique band structure is conducive to the effective separation and directional transport of photogenerated carriers, reduces nonradiative recombination losses, and thus significantly improves quantum yield.

[0066] (2) Lattice field analysis: Tanabe-Sugano analysis confirmed that high entropy caused the activator Eu to... 3+In a weak lattice field environment, phonon-assisted nonradiative transitions were significantly suppressed by adjusting the octahedral field strength.

[0067] (3) Electron-phonon coupling analysis: The Huang-Rhys factor was obtained by fitting the variable temperature spectrum. The high-entropy system was lower than that of the single-component system, which confirmed that the high-entropy structure reduced the electron-phonon coupling strength and reduced the energy dissipation in the form of lattice vibration, thereby improving the luminescence efficiency and thermal stability.

[0068] In summary, this invention, through the innovative application of the high-entropy engineering concept, has successfully prepared rare-earth-based gallium salt high-entropy fluorescent ceramic materials with excellent luminescent properties, which have broad application prospects in the field of solid-state lighting.

[0069] This invention is not limited to the preferred embodiments described above. Anyone can derive other forms of products under the guidance of this invention. However, regardless of any changes made in their shape or structure, any technical solution that is the same as or similar to this application falls within the protection scope of this invention.

Claims

1. A rare-earth-based gallium salt high-entropy red fluorescent ceramic material, characterized in that: The ceramic material described has a single-phase garnet structure and its general chemical formula is: RE3Ga5O 12 :xLn 3+ RE represents a combination of at least five different rare earth elements; Ln 3+ is the activator ion; x is the molar percentage of the activator ion relative to the total amount of RE sites; the ceramic material achieves red light emission under blue light excitation.

2. The rare-earth-based gallium salt high-entropy red fluorescent ceramic material according to claim 1, characterized in that: The rare earth elements mentioned include Y, La, Nd, Sm, Eu, Gd, Ho, Er, Yb and / or Lu.

3. The rare-earth-based gallium salt high-entropy red fluorescent ceramic material according to claim 1, characterized in that: The different rare earth elements are combined in equimolar ratios or near equimolar ratios.

4. The rare-earth-based gallium salt high-entropy red fluorescent ceramic material according to claim 1, characterized in that: The Ln 3+ Including Nd 3+ 、Sm 3+ Eu 3+ 、Tb 3+ and / or Tm 3+ .

5. The rare-earth-based gallium salt high-entropy red fluorescent ceramic material according to claim 1, characterized in that: The value range of x is [0.01, 0.15].

6. The method for preparing the ceramic material according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Mix and ball-mill the RE source, Ga source and activator source to obtain a primary slurry; after drying and sieving, the primary slurry is pressed into a primary green body; the primary green body is calcined once to obtain a pre-calcined product. The pre-calcined products of S2 and S1 are crushed and ball-milled to obtain a secondary slurry. The secondary slurry is dried, sieved, and then pressed into a secondary green body. The secondary green body is then calcined and crushed a second time to obtain a rare earth-based gallium salt high-entropy red fluorescent ceramic material.

7. The method for preparing ceramic materials according to claim 6, characterized in that: In S1, the RE source includes oxides of rare earth elements; the Ga source includes gallium oxide; and the activator source includes oxides of activator ions.

8. The method for preparing ceramic materials according to claim 6, characterized in that: In S1, the temperature of the first calcination is 1400~1550℃, the holding time is 2~6h, and the heating rate is 5~10℃ / min.

9. The method for preparing ceramic materials according to claim 6, characterized in that: In S2, the secondary calcination temperature is 1500~1650℃, the holding time is 4~10h, and the heating rate is 5~10℃ / min.

10. The application of the ceramic material described or prepared according to any one of claims 1-9 in applications including solid-state lighting, display devices, anti-counterfeiting labels, and / or optical thermometry.

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