Cr-Er-Yb tri-doped high-alumina spinel microcrystalline glass, preparation method and application thereof

Abstract

The application discloses a Cr-Er-Yb tri-doped high-alumina spinel microcrystalline glass as well as a preparation method and application thereof. 3+ The Cr-Er-Yb tri-doped high-alumina spinel microcrystalline glass realizes co-doping of Cr 3+ , Er 3+ , Yb three ions in the Cr-Er-Yb tri-doped high-alumina spinel microcrystalline glass, and is a high-alumina spinel microcrystalline glass with up / down conversion and synergistic effect and protection. The application overcomes problems of difficult melting of high-alumina content glass, uncontrollable crystallization and serious mismatch loss of ultraviolet and infrared wave bands due to band gap limitation of monocrystalline silicon cells, and obtains the microcrystalline glass with wide-spectrum photon conversion capacity, super-high hardness and good light transmittance, and the microcrystalline glass is especially suitable for a synergistic protection cover plate of a marine photovoltaic module.

Description

Technical Field

[0001] This invention belongs to the field of microcrystalline glass material technology, specifically relating to a rare earth ion (Cr). 3+ Er 3+ Yb 3+ Co-doped high-alumina spinel microcrystalline glass, its preparation method and application. Background Technology

[0002] Offshore photovoltaics is an important way to expand the use of renewable energy and reduce dependence on fossil fuels. However, offshore photovoltaic modules are exposed to extreme marine environments such as high salt spray, high humidity, and strong winds and waves for extended periods, placing extremely high demands on the corrosion resistance, mechanical strength, and long-term reliability of the materials. At the same time, the band gap of mainstream monocrystalline silicon cells (approximately 1.12 eV) limits their efficient utilization wavelength range to 600-980 nm, and photons in the ultraviolet and infrared regions are lost in large quantities due to spectral mismatch, resulting in limited energy conversion efficiency.

[0003] Rare-earth ion-doped transparent glass-ceramics possess both spectral conversion (upconversion / downconversion) and physical protection functions: downconversion cuts ultraviolet photons into visible light, while upconversion combines infrared photons into visible light, thus broadening the spectral response range of silicon solar cells; simultaneously, the high-hardness glass-ceramics can be directly used as protective covers for photovoltaic modules. However, current research still faces key scientific challenges: one is the presence of Cr in the co-doped system. 3+ Er 3+ Yb 3+ The energy transfer pathways between them are complex, and concentration quenching and reverse energy transfer are difficult to control; secondly, high-aluminum-content glass is difficult to melt and crystallization is uncontrollable, making it difficult to balance nanocrystal size and light transmittance; thirdly, material systems that simultaneously achieve efficient up / down conversion luminescence, ultra-high hardness, and high transparency have not yet been reported.

[0004] In the prior art, Cr 3+ While single-doped ZnAl2O4 spinel can achieve narrow-band red light emission under a strong crystal field, its application is limited to phosphor powder materials; Er 3+ -Yb 3+ While co-doped systems can achieve upconversion luminescence, their low hardness makes them unsuitable for extreme environments such as the deep sea. In existing tri-doped glass-ceramics, Cr... 3+ Yb 3+ and Er 3+ They are enriched in different crystal phases and do not form a synergistic energy effect in the same matrix. Summary of the Invention

[0005] The purpose of this invention is to address the problems in the prior art by rationally designing the composition of high-alumina glass and introducing Cr. 3+ Er 3+ Yb3+ By employing a co-doped system and a two-step controllable heat treatment process, a spinel glass-ceramic with excellent up / down conversion luminescence properties, a Vickers hardness ≥7.98 GPa, and red light transmittance ≥80% was successfully prepared. This invention marks the first time that Cr has been achieved in a single ZnAl2O4 spinel glass-ceramic system. 3+ -Er 3+ -Yb 3+ The co-doping of three ions, along with the ultra-high aluminum content that imparts high hardness to the material, has successfully achieved a combination of high hardness, high transmittance, and up / down conversion synergistic spectral modulation in the triple-doped microcrystalline glass, providing a novel material solution for spectral management in the complex environment faced by shallow-sea photovoltaic cells.

[0006] To achieve the above objectives, this invention provides a rare-earth-doped high-alumina spinel microcrystalline glass, its preparation method, and its application, in order to solve the problem that microcrystalline glass in the prior art is difficult to achieve broadband photon conversion, ultra-high hardness, and high light transmittance simultaneously.

[0007] This invention provides a Cr-Er-Yb triple-doped high-alumina spinel glass-ceramic, Cr 3+ Er 3+ Yb 3+ The Cr-Er-Yb triple-doped high-alumina spinel glass-ceramics are co-doped with three ions. The composition of the Cr-Er-Yb triple-doped high-alumina spinel glass-ceramics, in terms of the molar percentage of oxides, includes: SiO2: 30-40 mol%, Al2O3: 30-40 mol%, ZnO: 12-18 mol%, Li2O: 2-4 mol%, Na2O: 2-4 mol%, MgO: 1-3 mol%, ZrO2: 2-4 mol%, B2O3: 1-3 mol%, TiO2: 1-3 mol%, Cr2O3: 0.05 mol%, Er2O3: 0.3 mol%, Yb2O3: 0.1-1.0 mol%.

[0008] The Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass of this invention, Cr 3+ Er 3+ Yb 3+ Co-doping is achieved within the same crystal phase framework.

[0009] In a preferred embodiment of the present invention, the composition of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass, in terms of the molar percentage of oxides, is as follows: SiO2: 34.3 mol%, Al2O3: 36 mol%, ZnO: 15 mol%, Li2O: 2.5 mol%, Na2O: 2.75 mol%, MgO: 2 mol%, ZrO2: 2.5 mol%, B2O3: 2 mol%, TiO2: 2.5 mol%, Cr2O3: 0.05 mol%, Er2O3: 0.3 mol%, Yb2O3: 0.1 mol%.

[0010] In a preferred embodiment of the present invention, the composition of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass, in terms of the molar percentage of oxides, is as follows: SiO2: 33.8 mol%, Al2O3: 36 mol%, ZnO: 15 mol%, Li2O: 2.5 mol%, Na2O: 2.75 mol%, MgO: 2 mol%, ZrO2: 2.5 mol%, B2O3: 2 mol%, TiO2: 2.5 mol%, Cr2O3: 0.05 mol%, Er2O3: 0.3 mol%, Yb2O3: 0.6 mol%.

[0011] In a preferred embodiment of the present invention, the composition of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass, in terms of the molar percentage of oxides, is as follows: SiO2: 33.4 mol%, Al2O3: 36 mol%, ZnO: 15 mol%, Li2O: 2.5 mol%, Na2O: 2.75 mol%, MgO: 2 mol%, ZrO2: 2.5 mol%, B2O3: 2 mol%, TiO2: 2.5 mol%, Cr2O3: 0.05 mol%, Er2O3: 0.3 mol%, Yb2O3: 1.0 mol%.

[0012] In any of the above-mentioned preferred embodiments, the main crystalline phase of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass is ZnAl2O4 spinel, the secondary crystalline phase is ZrTiO4, and it contains a small amount of ZnSiO3.

[0013] Preferably, the ZnAl2O4 lattice contains Cr. 3+ Substitution of Al in ZnAl2O4 lattice 3+ The site, Er 3+ and Yb 3+ It is enriched within and at the grain boundaries of ZnAl2O4 grains. The Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass of this invention, Cr... 3+ Er3+ Yb 3+ Co-doping was achieved within the same ZnAl2O4 crystal framework to construct Cr 3+ -Yb 3+ -Er 3+ The series energy transfer channels enable the excitation light energy to be effectively transferred step by step during the up / down conversion process.

[0014] The Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass of this invention mainly consists of a high-alumina glass matrix and uniformly dispersed nano-sized ZnAl2O4 spinel crystals, ZrTiO4 crystals, and a small amount of ZnSiO3 crystals; Cr 3+ It mainly enters the ZnAl2O4 lattice to replace Al. 3+ site, Er 3+ and Yb 3+ It is concentrated inside the grains and near the grain boundaries.

[0015] Preferably, the grain size of the main crystalline phase ZnAl2O4 is 10-50 nm, and more preferably 10, 20, 30, 40, 50 nm and the range thereof.

[0016] Preferably, the 1 mm thick Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass has an average transmittance of ≥80% in the 600-800 nm red light band and a microhardness of ≥7.98 GPa.

[0017] Preferably, the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass emits Cr emission centered at 687 nm under 395 nm ultraviolet light excitation. 3+ Narrow-band sharp-line red light with color purity ≥68%; emits Er centered at 677 nm under 980 nm near-infrared light excitation. 3+ Strong red light, color purity ≥99.7%.

[0018] In this invention, SiO2 serves as the glass network forging body, forming the framework; the high content of Al2O3 (30-40 mol%) not only provides the aluminum source required for the spinel crystal phase, but also, with Al existing in the forms of [AlO4] and [AlO5], it reduces the diffusion barrier for spinel nucleation, endowing the glass with ultra-high Vickers hardness, providing a protective strategy for shallow-sea photovoltaics to cope with complex marine environments; ZnO and Al2O3 form the ZnAl2O4 spinel main crystal phase after heat treatment; Li2O and Na2O act as fluxes, lowering the melting temperature and serving as active components for ion exchange; ZrO2 and TiO2 synergistically act as nucleating agents, promoting heterogeneous nucleation and refining grains; B2O3 adjusts the glass melt viscosity, improving crystallization selectivity; Cr2O3 serves as a downconversion luminescence center, while Cr... 6+ / Cr 3+ The polymerization degree of the glass network can be adjusted; Er2O3 acts as the upconversion luminescence center, and Yb2O3 acts as the upconversion sensitizer, through Yb 3+ →Er 3+ Energy transfer is significantly enhanced, resulting in increased red light emission.

[0019] In the Cr-Er-Yb triple-doped high-alumina spinel glass-ceramic of this invention, the main crystalline phase is nanoscale (10-50 nm) ZnAl2O4 spinel, and the secondary crystalline phases are ZrTiO4 and a small amount of ZnSiO3. EDS observation shows that the elemental signals of Yb and Er exhibit common localization characteristics with Zn and Al, indicating that Yb in the ZnAl2O4 glass-ceramic of this invention... 3+ and Er 3+ It tends to accumulate at grains or grain boundaries. Rare earth ions (Cr) 3+ Mainly occupying Al in ZnAl2O4 3+ The octahedral sites form a strong crystal field (Dq / B≥2.6), thereby generating 2 E to 4 Narrow-band sharp-line red emission (687 nm) from the A2 transition. Meanwhile, Yb 3+ and Er 3+ Enriched in grains and grain boundaries, Yb under 980nm excitation 3+ After absorbing near-infrared photons, energy is transferred to Er. 3+ Then, through reverse energy transfer and cross-relaxation, Er... 3+ of 4 F 9 / 2 With a large population of energy levels, it ultimately emits high-purity red light at 677 nm (color purity ≥ 99.7%). To achieve a synergy between high Vickers hardness and transmittance, this invention overcomes the technical difficulties in melting, forming, and devitrification of the high Al2O3 system, successfully leveraging the hardness advantage of high-alumina microcrystalline glass, and further achieving a synergy of excellent optical performance (transmittance of approximately 80%, dual-mode red light emission).

[0020] The Cr-Er-Yb triple-doped high-alumina spinel glass-ceramic of this invention has a high Al content. Existing low-Al glasses have low Vickers hardness, while increasing the Al content leads to increased glass viscosity, hindering crystallization and causing devitrification, making them unsuitable for applications requiring high hardness and high transmittance, such as photovoltaics. Shallow-sea photovoltaic systems face severe environmental challenges such as high salt spray, high humidity, and strong swells, posing stringent challenges to the mechanical properties of photovoltaic cell cover glass. This invention successfully achieved the preparation of high-alumina content microcrystalline glass by controlling the glass composition. The increased Al content enhances the stability of the glass network, successfully achieving a Vickers hardness of 7.98 GPa. Simultaneously, the high aluminum content promotes the preferential precipitation of the ZnAl2O4 spinel phase during heat treatment, effectively suppressing the non-radiative transitions of rare earth ions. Ultimately, this allows the three dopant ions to each occupy a stable local crystal field in a high-Al environment, thereby simultaneously achieving efficient down-conversion and up-conversion red light emission.

[0021] The synergistic effect brought about by this invention is first reflected in the upstream and downstream synergistic conversion. Because the optimal response range of current monocrystalline silicon solar cells is near red light, the energy in the ultraviolet and infrared bands of sunlight is almost impossible to convert and utilize, resulting in energy waste. However, the upstream and downstream synergistic conversion designed in this invention utilizes Cr... 3+ Provides downconversion and Er excitation at 395 nm. 3+ -Yb 3+ This invention provides upconversion with 980 nm excitation while simultaneously achieving red light emission, enabling coverage of the ultraviolet-visible-near-infrared spectrum—something that cannot be achieved in existing single-doped or double-doped systems. Secondly, regarding the synergy between mechanical and optical properties, the mechanical properties of glass-ceramics are affected by the matrix material and the type and size of the precipitated crystals. Too few precipitated crystals are not conducive to hindering crack propagation, resulting in insufficient Vickers hardness, while too many crystals or their excessive size lead to increased light scattering and decreased transmittance. This invention achieves a Vickers hardness of 7.98 GPa and a transmittance of approximately 80% in a Cr-Er-Yb triple-doped system by controlling the crystallization process, thus possessing both high Vickers hardness and high transmittance.

[0022] The present invention also provides a method for preparing Cr-Er-Yb triple-doped high-alumina spinel glass according to any one of the above claims, comprising the following steps:

[0023] Step 1: Weigh the raw materials according to the composition, mix them evenly, and obtain the mixture;

[0024] Step 2: Melt the mixture to obtain molten glass;

[0025] Step 3: Shape the molten glass and anneal it to obtain the base glass;

[0026] Step 4: Heat treat the base glass to obtain the microcrystalline glass.

[0027] In any of the above-mentioned preferred embodiments, the melting in step 2 includes: heating from room temperature to 300°C at a heating rate of 2-5°C / min, then heating to 1600°C at a rate of 5°C / min, then heating to 1650°C at a rate of 2°C / min, and holding at 1650°C for 2-4 hours.

[0028] In any of the above-mentioned preferred embodiments, in step 2, the heating rate from room temperature to 300°C is preferably 2, 3, 4, or 5°C / min or a range thereof.

[0029] In any of the above-mentioned preferred embodiments, in step 2, the temperature is maintained at 1650℃ for 2, 3, or 4 hours, or within the range thereof.

[0030] In any of the above-mentioned preferred embodiments, the annealing temperature in step 3 is 500-650℃, and the holding time is 2-6 h.

[0031] Preferably, the annealing temperature in step 3 is 500, 550, 600, 650°C or a range thereof.

[0032] Preferably, the annealing holding time in step 3 is 2, 3, 4, 5, 6 hours or a range thereof.

[0033] Preferably, in any of the above, the heat treatment in step 4 is a two-step heat treatment: first at the glass transition temperature T g Nucleation at 20-40℃ for 2-4 hours, followed by crystallization at the peak temperature T. c Crystallization occurred in the vicinity for 0.5-2 hours; the heating rate was 2-5℃ / min.

[0034] In any of the above-mentioned preferred embodiments, step 4 involves first cutting and polishing the base glass, followed by two heat treatment steps.

[0035] In any of the above-mentioned preferred embodiments, in the two-step heat treatment of step 4, the first step is performed at the glass transition temperature T. g The above-mentioned nucleation temperatures are 20-40℃ for 2, 3, and 4 hours, and the time range between them.

[0036] Preferably, in step 4, during the two-step heat treatment, the crystallization peak temperature T is... c Crystallization in the vicinity occurs at 0.5, 1, 1.5, and 2 hours, and in between.

[0037] In any of the above-mentioned preferred embodiments, the heating rate in the two heat treatment steps of step 4 is 2, 3, 4, or 5 °C / min or a range thereof.

[0038] Preferably, the glass transition temperature T is [missing information]. gThe temperature of 20-40℃ is 720-760℃, and more preferably 720, 730, 740, 750, 760℃ and the range therebetween.

[0039] Preferably, the crystallization peak temperature T is [missing information]. c The surrounding temperature is 900-940℃, more preferably 900, 910, 920, 924, 930, 940℃ and the range therebetween. The crystallization peak temperature described in this invention... T c The temperature is the crystallization peak temperature. T c The temperature in the vicinity is 900-940℃.

[0040] In any of the above-mentioned preferred embodiments, the heat treatment in step 4 is a two-step heat treatment: first nucleation at 720-760℃ for 2-4 hours, and then crystallization at 900-940℃ for 0.5-2 hours; the heating rate is 2-5℃ / min.

[0041] Preferably, the crystallinity of the microcrystalline glass obtained after heat treatment in step 4 is 65-72%, and the grain size of the main crystalline phase ZnAl2O4 is 10-50 nm.

[0042] The preferred embodiment of the present invention is the preparation method of Cr-Er-Yb triple-doped high-alumina spinel glass, which includes the following steps:

[0043] Step 1: Weigh the raw materials according to the composition and grind and mix them thoroughly in an agate mortar for 1 hour;

[0044] Step 2: Place the mixture in a quartz crucible and raise the temperature from room temperature to 300°C at 3°C / min, then to 1600°C at 5°C / min, and then to 1650°C at 2°C / min, and hold for 3 hours.

[0045] Step 3: Pour the molten glass into a preheated graphite mold to form it, then transfer it to a muffle furnace at 500-650℃ for annealing for 2-6 hours, and cool it with the furnace to obtain the base glass;

[0046] Step 4: After cutting and polishing the base glass, perform a two-step heat treatment: first, raise the temperature to 720-760℃ (i.e., T) at a rate of 2-5℃ / min. g Nucleation at +20~40℃ for 3 h, followed by heating at 2-5℃ / min to 900-940℃ (i.e., T). c Crystallize in the vicinity for 1 hour, then cool in the furnace to obtain microcrystalline glass.

[0047] In step 4, the cutting and polishing of the base glass are conventional methods in the prior art.

[0048] In the above preparation method, the temperature and time of nucleation and crystallization can be finely adjusted according to the composition; the crystallinity of the microcrystalline glass can reach 65-72%.

[0049] The present invention also provides the application of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass described in any of the above claims in the preparation of photovoltaic module enhancement protective cover plates.

[0050] The preferred embodiment of any of the above is the application of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass as a cover material in marine photovoltaic modules.

[0051] In any of the above-mentioned preferred embodiments, the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass, as an enhancement and protective cover for the photovoltaic module, has the functions of spectral up-conversion, down-conversion, and high-hardness physical protection.

[0052] Unlike existing single / double-doped systems that only achieve spectral conversion in a single direction, this invention innovatively achieves "up / down" dual-mode synergistic spectral modulation within the same microcrystalline glass matrix, under 395 nm excitation by Cr... 3+ Dominated downconversion red light emission, excited by Er at 980 nm 3+ It dominates upconversion red light emission, achieving two spectral conversions simultaneously in the same material.

[0053] This invention provides the application of the rare earth-doped high-alumina spinel microcrystalline glass described in any of the above claims in the preparation of protective covers for photovoltaic modules, especially as a cover material in marine photovoltaic modules that combines spectral up-conversion, down-conversion, and high-hardness physical protection functions.

[0054] The beneficial effects of this invention are as follows:

[0055] (1) This invention overcomes the problem of difficult melting of high-alumina glass by designing with high aluminum content (30-40 mol%) and combining fluxes such as B2O3 and TiO2, and obtains spinel microcrystalline glass with high aluminum content and ultra-high hardness.

[0056] (2) This invention is the first to achieve Cr in high-alumina spinel glass. 3+ Er 3+ Yb 3+ Tri-ion co-doping, utilizing the low phonon energy environment (approximately 700-800 cm⁻¹) provided by the crystal phase. -1 The strong crystal field and the strong crystal field significantly suppressed non-radiative relaxation, making Cr 3+ downconversion luminescence and Yb 3+ To Er 3+ The upconversion energy transfer efficiency is greatly improved.

[0057] (3) The microcrystalline glass obtained by the present invention emits deep red light with high color purity (68%) under 395 nm excitation and emits pure red light with color purity of up to 99.7% under 980 nm excitation. The transmittance of the red light band is ≥80%, and the Vickers hardness is ≥7.98GPa. It has both excellent optical conversion performance and mechanical protection performance.

[0058] (4) The preparation process of this invention is controllable, and the two-step heat treatment can achieve a balance between crystallinity and light transmittance, which is suitable for industrial production. Attached Figure Description

[0059] Figure 1 This is the DSC spectrum of the base glass in preferred embodiment 2 of the present invention.

[0060] Figure 2 In the preferred embodiment 2 of the present invention, the XRD pattern of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass was obtained by heat treatment at 924 °C for 1 h and then naturally cooling to room temperature.

[0061] Figure 3 In the preferred embodiment 2 of the present invention, the FTIR spectrum of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass was prepared by heat treatment at 924 °C for 1 h and then naturally cooled to room temperature.

[0062] Figure 4 In the preferred embodiment 2 of the present invention, the TEM image of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass was obtained by heat treatment at 924 °C for 1 h and then naturally cooling to room temperature.

[0063] Figure 5 In the preferred embodiment 2 of the present invention, the EDS image of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass was obtained by heat treatment at 924 °C for 1 h and then naturally cooling to room temperature.

[0064] Figure 6 In the preferred embodiment 2 of the present invention, the downconversion fluorescence spectrum of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass was obtained by heat treatment at 924 °C for 1 h and then naturally cooling to room temperature.

[0065] Figure 7 In the preferred embodiment 2 of the present invention, the upconversion fluorescence spectrum of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass is obtained by heat treatment at 924 °C for 1 h and then naturally cooling to room temperature.

[0066] Figure 8In the preferred embodiment 2 of the present invention, the transmittance curve of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass is obtained by heat treatment at 924 °C for 1 h and then naturally cooling to room temperature.

[0067] Figure 9 In the preferred embodiment 2 of the present invention, the microhardness image of the Cr-Er-Yb triple-doped high-alumina spinel glass is obtained by heat treatment at 924 °C for 1 h and then naturally cooling to room temperature. Detailed Implementation

[0068] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0069] The Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glasses provided in the preferred embodiments 1 to 3 of this invention have similar properties. Their beneficial technical effects are described in embodiments 1 to 3, and... Figures 1 to 9 Example 2 provides the detection image results.

[0070] Figure 1 This is the DSC spectrum of the base glass in preferred embodiment 2 of the present invention.

[0071] Figure 2 In the preferred embodiment 2 of the present invention, the XRD pattern of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass was obtained by heat treatment at 924 °C for 1 h and then naturally cooling to room temperature.

[0072] Figure 3 In the preferred embodiment 2 of the present invention, the FTIR spectrum of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass was prepared by heat treatment at 924 °C for 1 h and then naturally cooled to room temperature.

[0073] Figure 4 In the preferred embodiment 2 of the present invention, the TEM image of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass was obtained by heat treatment at 924 °C for 1 h and then naturally cooling to room temperature.

[0074] Figure 5 In the preferred embodiment 2 of the present invention, the EDS image of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass was obtained by heat treatment at 924 °C for 1 h and then naturally cooling to room temperature.

[0075] Figure 6In the preferred embodiment 2 of the present invention, the downconversion fluorescence spectrum of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass was obtained by heat treatment at 924 °C for 1 h and then naturally cooling to room temperature.

[0076] Figure 7 In the preferred embodiment 2 of the present invention, the upconversion fluorescence spectrum of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass is obtained by heat treatment at 924 °C for 1 h and then naturally cooling to room temperature.

[0077] Figure 8 In the preferred embodiment 2 of the present invention, the transmittance curve of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass is obtained by heat treatment at 924 °C for 1 h and then naturally cooling to room temperature.

[0078] Figure 9 In the preferred embodiment 2 of the present invention, the microhardness image of the Cr-Er-Yb triple-doped high-alumina spinel glass is obtained by heat treatment at 924 °C for 1 h and then naturally cooling to room temperature.

[0079] Example 1

[0080] The ingredients are prepared according to the following molar percentages: SiO2: 34.3 mol%, Al2O3: 36 mol%, ZnO: 15 mol%, Li2O: 2.5 mol%, Na2O: 2.75 mol%, MgO: 2 mol%, ZrO2: 2.5 mol%, B2O3: 2 mol%, TiO2: 2.5 mol%, Cr2O3: 0.05 mol%, Er2O3: 0.3 mol%, Yb2O3: 0.1 mol% (sample number CrE3Yb1).

[0081] The weighed raw materials (lithium carbonate, sodium carbonate, magnesium oxide, zinc oxide, aluminum oxide, silicon dioxide, zirconium oxide, boron oxide, titanium oxide, chromium oxide, erbium oxide, and ytterbium oxide, all analytical grade) were thoroughly ground and mixed in an agate mortar for 1 hour. The mixture was placed in a quartz crucible and placed in a high-temperature resistance furnace. The temperature was increased from room temperature to 300°C at 3°C / min, then to 1600°C at 5°C / min, and finally to 1650°C at 2°C / min, and held for 3 hours. The molten glass was poured into a graphite mold preheated to 600°C and shaped. It was then quickly transferred to a muffle furnace at 600°C for annealing for 2 hours and cooled in the furnace to obtain the base glass (PG-CrE3Yb1). The base glass was cut into 1 cm × 1 cm × 1 mm thin slices, polished, and cleaned. According to the DSC results (T... g =706℃, T c= 907℃), the thin film was nucleated at 746℃ for 3 h by heating at 5℃ / min, and then crystallized at 907℃ for 1 h by heating at 5℃ / min. It was then cooled in the furnace to obtain microcrystalline glass (GC-CrE3Yb1).

[0082] Testing revealed that the main crystalline phase of this glass-ceramic is ZnAl₂O₄, with secondary phases of ZrTiO₄ and a small amount of ZnSiO₃, and a crystallinity of 66.2%. Under 395 nm excitation, it emits a narrow band of red light with a main emission peak at 687 nm, chromaticity coordinates (0.40, 0.2393), and a color purity of 50%. Under 980 nm excitation, it emits red light with a main emission peak at 677 nm, chromaticity coordinates (0.6286, 0.3667), and a color purity of 98.6%. The 1 mm thick sample exhibits an average transmittance of approximately 82% in the 600-800 nm wavelength range and a Vickers hardness of 7.96 GPa.

[0083] Example 2

[0084] The molar percentage of ingredients in Example 2 is basically the same as in Example 1, except that the molar ratio of Yb₂O₃ is 0.6 mol%, corresponding to an adjustment of SiO₂ to 33.8 mol% (sample CrE₃Yb₆). Basic glass T g =742℃, T c =924℃. The nucleation temperature is set at 772℃, and the crystallization temperature is 924℃.

[0085] The resulting glass-ceramic exhibits a crystallinity of 71.5% and uniform grain size (approximately 20-30 nm). Under 395 nm excitation, the emission intensity at 687 nm is significantly enhanced, with chromatic coordinates (0.5611, 0.2693) and a color purity of 67%. Under 980 nm excitation, the intensity of the upconversion red light at 677 nm is approximately 80 times higher than in Example 1, with chromatic coordinates (0.7067, 0.2913) and a color purity of 99.7%. The red light transmittance is approximately 80%, and the Vickers hardness reaches 7.98 GPa, demonstrating optimal overall performance.

[0086] Example 3

[0087] The molar percentage of ingredients in Example 3 is basically the same as in Example 1, except that the molar ratio of Yb₂O₃ is 1.0 mol%, corresponding to an adjustment of SiO₂ to 33.4 mol% (sample CrE₃Yb₁₀). Basic glass T g =745℃, T c =935℃. Nucleation temperature 775℃, crystallization temperature 935℃.

[0088] The resulting glass-ceramic had a crystallinity of 65.6%, with localized coarsening and agglomeration of the grains. Under 395 nm excitation, the downconversion luminescence intensity was slightly lower than that of Example 2; under 980 nm excitation, the upconversion luminescence intensity decreased, but the color purity remained as high as 99.8%. The red light transmittance was approximately 78%, and the Vickers hardness was 7.85 GPa.

[0089] Comparative Example

[0090] The comparative example's molar percentage of ingredients and preparation method are basically the same as in Example 1. The difference lies in the fact that the comparative example uses the same matrix glass without rare earth ions (no Cr2O3, Er2O3, Yb2O3). After the same heat treatment, it has no up / down conversion luminescence capability, a hardness of approximately 7.5 GPa, and a transmittance of approximately 90%. This indicates that rare earth doping has a limited effect on transmittance while achieving spectral conversion and improving the Vickers hardness of the sample.

[0091] In summary, this invention introduces Cr 3+ -Er 3+ -Yb 3+ By combining the strong crystal field effect and low phonon energy environment of high-alumina spinel glass-ceramics with a co-doped system, a glass-ceramic material with efficient up / down conversion red light emission, ultra-high hardness (≥7.98 GPa), and good light transmittance (red light transmittance ≥80%) has been successfully prepared. This material is particularly suitable for enhancing protective covers for marine photovoltaic modules, converting unused ultraviolet and infrared photons into highly responsive red light for silicon cells, while resisting the mechanical impact of the marine environment.

[0092] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A Cr-Er-Yb triple-doped high-alumina spinel glass-ceramic, characterized in that, Cr 3+ Er 3+ Yb 3+ The Cr-Er-Yb triple-doped high-alumina spinel glass-ceramics are co-doped with three ions. The composition of the Cr-Er-Yb triple-doped high-alumina spinel glass-ceramics, in terms of the molar percentage of oxides, includes: SiO2: 30-40 mol%, Al2O3: 30-40 mol%, ZnO: 12-18 mol%, Li2O: 2-4 mol%, Na2O: 2-4 mol%, MgO: 1-3 mol%, ZrO2: 2-4 mol%, B2O3: 1-3 mol%, TiO2: 1-3 mol%, Cr2O3: 0.05 mol%, Er2O3: 0.3 mol%, Yb2O3: 0.1-1.0 mol%.

2. The Cr-Er-Yb triple-doped high-alumina spinel glass-ceramic according to claim 1, characterized in that, The main crystalline phase of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass is ZnAl2O4 spinel, and the secondary crystalline phase is ZrTiO4. The ZnAl2O4 lattice contains Cr. 3+ Substitution of Al in ZnAl2O4 lattice 3+ site, Er 3+ and Yb 3+ It is enriched in the interior of ZnAl2O4 grains and at grain boundaries.

3. The Cr-Er-Yb triple-doped high-alumina spinel glass-ceramic according to claim 2, characterized in that, The grain size of the main crystalline phase ZnAl2O4 is 10-50 nm.

4. The Cr-Er-Yb triple-doped high-alumina spinel glass-ceramic according to any one of claims 1 to 3, characterized in that, The 1 mm thick Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass has an average transmittance of ≥80% in the 600-800 nm red light band and a microhardness of ≥7.98 GPa.

5. The Cr-Er-Yb triple-doped high-alumina spinel glass-ceramic according to claim 1, characterized in that, The Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass emits Cr emission centered at 687 nm under 395 nm ultraviolet light excitation. 3+ Narrow-band sharp-line red light with color purity ≥68%; emits Er centered at 677 nm under 980 nm near-infrared light excitation. 3+ Strong red light, color purity ≥99.7%.

6. The method for preparing Cr-Er-Yb triple-doped high-alumina spinel glass-ceramics according to any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Weigh the raw materials according to the composition, mix them evenly, and obtain the mixture; Step 2: Melt the mixture to obtain molten glass; Step 3: Shape the molten glass and anneal it to obtain the base glass; Step 4: Heat treat the base glass to obtain the microcrystalline glass.

7. The preparation method according to claim 6, characterized in that, The melting process described in step 2 includes: heating from room temperature to 300°C at a heating rate of 2-5°C / min, then heating to 1600°C at 5°C / min, then heating to 1650°C at 2°C / min, and holding at 1650°C for 2-4 hours.

8. The preparation method according to claim 7, characterized in that, The annealing temperature in step 3 is 500-650℃, and the holding time is 2-6 h.

9. The preparation method according to claim 6, characterized in that, The heat treatment described in step 4 is a two-step heat treatment: first at the glass transition temperature T g Nucleation at 20-40℃ for 2-4 hours, followed by crystallization at the peak temperature T. c Crystallization was carried out at temperatures ranging from 0.5 to 2 h; the heating rate was 2-5 °C / min.

10. The application of the Cr-Er-Yb triple-doped high-alumina spinel microcrystalline glass according to any one of claims 1-5 in the preparation of photovoltaic module enhancement protective cover plates.

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