Up-conversion white light emission oxide with porous surface as well as preparation method and application of up-conversion white light emission oxide

Abstract

The invention discloses a surface-porous up-conversion white light emission oxide, a preparation method thereof and application of the surface-porous up-conversion white light emission oxide in a luminescent material. The chemical expression of the surface-porous up-conversion white light emission oxide is Zr < 1-x-y > Yb < x > Re < y > O < 2 >, Re is one or more than two of Er, Ho and Tm, x and y represent atomic ratios and are 0.2 lt, and y represents atomic ratios and is 0.2 lt. 0 < = y < = 0.1. The preparation method adopts a sol-gel method, and comprises the following steps: mixing a Zr precursor, a Yb precursor, absolute ethyl alcohol, acid and a selectively added Re precursor, heating and stirring until xerogel is obtained, further drying the xerogel, and calcining to obtain the surface porous up-conversion white light emission oxide, the acid comprises one or more than two of acetic acid, hydrochloric acid, sulfuric acid and nitric acid and citric acid.

Description

Technical Field

[0001] This invention relates to the field of luminescent materials, specifically to a porous upconversion white light emitting oxide, its preparation method, and its applications. Background Technology

[0002] The information disclosed in this background section is intended only to enhance understanding of the overall background of the invention and is not necessarily to be construed as an admission or in any way implying that such information constitutes prior art known to those skilled in the art.

[0003] White light plays a vital role for humanity and is now widely used in various fields such as biomedicine, 3D displays, liquid crystal displays, and lighting equipment. With technological advancements, significant progress has been made in the manufacture of white light-emitting materials and methods.

[0004] Recently, a novel upconversion white light emission phenomenon has been observed in various materials, including rare-earth ion-activated upconversion phosphors, graphene, and organometallic compounds. Characterized by the fact that as the excitation power density increases, the emission spectrum gradually transitions from a discrete emission mode to continuous white light extending into the infrared band, or, when the excitation power density reaches a certain threshold, it transitions from a non-emitting state to a white light emission state. This emission phenomenon is termed near-infrared laser-driven continuous white light emission. Wu et al. published a paper detailing this phenomenon (Wu J, Zheng G, Liu X, et al. Near-infrared laser driven white light continuum generation: Materials, photophysical behaviours and applications[J]. Chemical Society Reviews, 2020, 49(11): 3461-3483.).

[0005] Studies have shown that the mechanism of this white light emission is thermal radiation luminescence, while other studies have indicated that this white light emission is generated under the combined action of thermal radiation and Raman scattering (Wu J, Xu C, Qiu J, et al. Conversion of constant-wave near-infrared laser to continuum white light by yb-doped oxides[J]. Journal of Materials Chemistry C, 2018, 6(28): 7520-7526.) or mainly through photon avalanche (Li D, Cui H, Qin G, et al. Photoinduced photon avalanche turns white objects into bright blackbodies[J]. Communications Physics, 2023, 6(1):120.). Therefore, this invention increases the thermal conductivity of the phosphor by modifying its morphology and increasing the surface porosity, thereby improving the intensity of white light emission. At the same time, the increase in specific surface area increases the number of luminescent sites, further improving the luminescence intensity.

[0006] Currently, common methods for preparing porous zirconia mainly involve adding pore-forming agents and foaming agents to zirconia slurry and then sintering it at high temperatures to obtain porous zirconia (e.g., the patent specification with publication number CN115160017A). These methods are cumbersome. This invention, however, directly obtains porous zirconia phosphors through an optimized sol-gel method, resulting in a simpler preparation method. The porous zirconia obtained by this method exhibits superior upconversion luminescence properties, and the prepared surface-porous zirconia shows promise for applications in lighting, catalysis, adsorption, and filtration. Summary of the Invention

[0007] This invention provides a surface-porous upconversion white light emitting oxide, its preparation method, and its applications. This surface-porous upconversion white light emitting oxide can emit white light under near-infrared light excitation (e.g., 976 nm, 808 nm, etc.) and has a porous morphology, making it applicable to fields such as lighting, catalysis, adsorption, filtration, solar cells, and anti-counterfeiting inks.

[0008] The specific technical solution is as follows: In a first aspect, the present invention provides a surface-porous upconversion white light emitting oxide, with the chemical formula Zr 1-x-y Yb x Re yO2, where: Re is one or more of Er, Ho, and Tm, x and y represent atomic ratios, and 0.2 < x ≤ 0.4. Further, 0.3 ≤ x ≤ 0.4. More specifically, 0.3 < x ≤ 0.4, and 0 ≤ y ≤ 0.1 (when y = 0, it means no Re element is doped), such as 0, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.1, etc.

[0009] The surface porous upconversion white light-emitting oxide described above uses ZrO2 as the matrix material, and the doping element is Yb 3+ or on the basis of Yb 3+ further add Er 3+ , Ho 3+ , Tm 3+ one or more of them.

[0010] Further, the crystal phase of the surface porous upconversion white light-emitting oxide is a cubic phase.

[0011] Further, the particle size distribution of the surface porous upconversion white light-emitting oxide is 0.2 - 100 μm.

[0012] Further, the average pore diameter of the surface porous upconversion white light-emitting oxide is 0.02 - 3 μm, such as 0.1 μm, 0.5 μm, 0.8 μm, etc.

[0013] In the second aspect, the present invention provides a preparation method of the surface porous upconversion white light-emitting oxide described in the first aspect. Using the sol-gel method, it includes: mixing a Zr precursor, a Yb precursor, absolute ethanol, an acid, and an optionally added (i.e., can be added or not added) Re precursor and heating and stirring until a dry gel is obtained. The dry gel is further dried and then calcined to obtain the surface porous upconversion white light-emitting oxide; The acid includes one or more of acetic acid, hydrochloric acid, sulfuric acid, nitric acid, and citric acid.

[0014] Further, in the preparation method described above, the Zr precursor, the Yb precursor, and the optionally added Re precursor are fed according to the proportional relationship reflected by the chemical formula.

[0015] Further, the Zr precursor, the Yb precursor, and the Re precursor independently include one or more of nitrates, halides, carbonates, acetates, and organic salts, such as zirconium n-butoxide, ytterbium chloride, erbium nitrate, holmium nitrate, thulium nitrate, holmium chloride, thulium chloride, etc.

[0016] Furthermore, the ratio of the molar amount of citric acid to the total molar amount of metal ions is 0.5 to 4:1, for example, 1:1, 2:1, 3:1, etc., preferably 1 to 3:1, and more preferably 2:1. The total molar amount of metal ions refers to the total molar amount of Zr ions, Yb ions, and selectively added Re ions.

[0017] Furthermore, in the preparation method, the heating and stirring temperature is 60~200 ℃, preferably 120~200 ℃, such as 180 ℃.

[0018] Furthermore, in the preparation method described above, the heating and stirring time is 1~12 h.

[0019] Furthermore, in the preparation method, the drying temperature is 60~250 ℃, preferably 70~100 ℃, such as 80 ℃.

[0020] Furthermore, in the preparation method, the drying time is 1~24 h, preferably 8~14 h, such as 10 h.

[0021] Furthermore, in the preparation method, the calcination temperature is 600~1600 ℃, preferably 700~1100 ℃, such as 1000 ℃.

[0022] Furthermore, in the preparation method, the calcination heating rate is 1~15 ℃ / min, preferably 5~10 ℃ / min.

[0023] Furthermore, in the preparation method, the calcination time is 3~24 h, preferably 5~10 h.

[0024] In the aforementioned preparation method, the cooling process after calcination affects grain growth. Preferably, the preparation method further includes furnace cooling after calcination.

[0025] Furthermore, the preparation method also includes a grinding operation after furnace cooling.

[0026] Thirdly, the present invention provides the application of the surface porous upconversion white light emitting oxide described in the first aspect in luminescent materials.

[0027] The surface-porous upconversion white light emitting oxide of the present invention can emit strong white light when excited by near-infrared lasers such as 976 nm or 808 nm. Compared with the corresponding rare earth-doped oxide without surface pores, its white light emission intensity is stronger.

[0028] Compared with the prior art, the beneficial effects of this invention are as follows: 1) Compared with other methods for preparing porous zirconia, the method for synthesizing surface porous upconversion white light emitting oxide of the present invention is simple, does not require the addition of pore-forming agents and foaming agents, is environmentally friendly, and has low production costs.

[0029] 2) The oxide upconversion luminescent material of the present invention has the advantages of high melting point, good mechanical strength, high chemical stability and high thermal stability.

[0030] 3) The pore size of the surface porous upconversion white light emitting oxide prepared by the present invention can be easily varied within a wide range by adjusting the raw material ratio and preparation process parameters (such as stirring temperature, drying temperature, drying time, calcination temperature, calcination time, etc.) to meet different needs.

[0031] 4) Compared with conventional upconversion white light emitting phosphors (without surface pores), the surface porous oxide prepared by this invention has a higher white light emission intensity. Attached Figure Description

[0032] Figure 1 These are the X-ray diffraction (XRD) patterns of the upconversion oxides obtained in Examples 1-8.

[0033] Figure 2 The X-ray diffraction patterns of the upconversion oxides obtained in Comparative Examples 1 to 8 are shown.

[0034] Figure 3 This is a scanning electron microscope (SEM) image of the upconversion oxide obtained in Example 7.

[0035] Figure 4 This is a scanning electron microscope image of the upconversion oxide obtained in Example 8.

[0036] Figure 5 This is a scanning electron microscope image of the upconversion oxide obtained in Example 10.

[0037] Figure 6 This is a scanning electron microscope image of the upconversion oxide obtained in Comparative Example 8.

[0038] Figure 7 The upconversion oxides obtained in Example 7 and Comparative Example 7 are at 400 W / cm 2 and 500 W / cm 2 The photoluminescence spectrum under 976 nm laser excitation.

[0039] Figure 8 The upconversion oxides obtained in Example 8 and Comparative Example 8 are at 400 W / cm 2 and 500 W / cm 2 The photoluminescence spectrum under 976 nm laser excitation.

[0040] Figure 9 The upconversion oxides obtained in Examples 8, 10, 12, and 14 are at 500 W / cm². 2 The photoluminescence spectrum under 976 nm laser excitation. Detailed Implementation

[0041] The present invention will be further described below with reference to the accompanying drawings and 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.

[0042] Example 1: Zr 0.99 Yb 0.01 The preparation process of O2 oxide upconversion phosphor is as follows: Measure 4.53 mL of zirconium n-butoxide, weigh 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid, mix them and add them to a beaker. Then add 150 mL of anhydrous ethanol, 1 mL of hydrochloric acid and 1 mL of acetic acid and stir for 1-4 h to obtain a liquid mixture. Heat and stir at 180 °C until dry to obtain a dry gel. Transfer the dry gel to an oven and keep it at 80 °C for 10 h for further drying. Place the dried gel in a muffle furnace and calcine it at a heating rate of 10 °C / min to 1000 °C for 10 h. After cooling the sintered body in the furnace, grind it to obtain a porous upconversion white light emitting oxide, namely Zr. 0.99 Yb 0.01 O2 oxide upconversion phosphor (a single-doped Yb zirconium oxide phosphor).

[0043] Example 2: Zr 0.98 Yb 0.02 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, the method is to measure 4.48 mL of zirconium n-butoxide, weighing 0.0775 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker. All other steps are the same.

[0044] Example 3: Zr 0.96 Yb 0.04 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, the method is to measure 4.39 mL of zirconium n-butoxide, weighing 0.1550 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker. All other steps are the same.

[0045] Example 4: Zr 0.94 Yb 0.06 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, the method is to measure 4.30 mL of zirconium n-butoxide, weigh 0.2325 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mix them in a beaker. All other steps are the same.

[0046] Example 5: Zr 0.90 Yb 0.10 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, the method is to measure 4.15 mL of zirconium n-butoxide, weighing 0.3875 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker. All other steps are the same.

[0047] Example 6: Zr 0.80 Yb 0.20 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, we measure 3.70 mL of zirconium n-butoxide, weighing 0.7750 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker. All other steps are the same.

[0048] Example 7: Zr 0.70 Yb 0.30 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, we measure 3.20 mL of zirconium n-butoxide, weighing 1.1625 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker. All other steps are the same.

[0049] Example 8: Zr 0.60 Yb 0.40 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, the method is to measure 2.75 mL of zirconium n-butoxide, weigh 1.5500 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mix them in a beaker. All other steps are the same.

[0050] Example 9: Zr 0.68 Yb 0.30 Er 0.02 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, we measure 3.10 mL of zirconium n-butoxide, weighing 1.1625 g of ytterbium chloride, 0.0887 g of erbium nitrate and 3.8424 g of anhydrous citric acid and mixing them in a beaker. All other steps are the same.

[0051] Example 10: Zr 0.58 Yb 0.40 Er 0.02 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, 2.65 mL of zirconium n-butoxide, weighing 1.5500 g of ytterbium chloride, 0.0887 g of erbium nitrate and 3.8424 g of anhydrous citric acid and mixing them in a beaker are measured and added to the beaker. All other steps are the same.

[0052] Example 11: Zr 0.58 Yb 0.40 Ho 0.02 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, the method is to measure 2.65 mL of zirconium n-butoxide, weighing 1.5500 g of ytterbium chloride, 0.0758 g of holmium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker. All other steps are the same.

[0053] Example 12: Zr 0.58 Yb 0.40 Ho 0.02 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, we measure 2.65 mL of zirconium n-butoxide, weighing 1.5500 g of ytterbium chloride, 0.0882 g of holmium nitrate and 3.8424 g of anhydrous citric acid and mixing them in a beaker. All other steps are the same.

[0054] Example 13: Zr 0.58 Yb 0.40 Tm 0.02 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, we measure 2.65 mL of zirconium n-butoxide, weighing 1.5500 g of ytterbium chloride, 0.0767 g of thulium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker. All other steps are the same.

[0055] Example 14: Zr 0.58 Yb 0.40 Tm 0.02 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, the method is to measure 2.65 mL of zirconium n-butoxide, weighing 1.5500 g of ytterbium chloride, 0.0890 g of thulium nitrate and 3.8424 g of anhydrous citric acid and mixing them in a beaker. All other steps are the same.

[0056] Comparative Example 1: Zr 0.99 Yb 0.01 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, the method is to measure 4.53 mL of zirconium n-butoxide and weigh 0.0387 g of ytterbium chloride and mix them in a beaker. All other aspects are the same.

[0057] Comparative Example 2: Zr 0.98 Yb 0.02 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in the beaker, the method is to measure 4.48 mL of zirconium n-butoxide and weigh 0.0775 g of ytterbium chloride and mix them in the beaker. All other steps are the same.

[0058] Comparative Example 3: Zr 0.96 Yb 0.04 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in the beaker, 4.39 mL of zirconium n-butoxide and weighing 0.1550 g of ytterbium chloride are measured and mixed in the beaker. All other parts are the same.

[0059] Comparative Example 4: Zr 0.94 Yb 0.06 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in the beaker, 4.30 mL of zirconium n-butoxide and weighing 0.2325 g of ytterbium chloride are measured and mixed in the beaker. All other parts are the same.

[0060] Comparative Example 5: Zr 0.90 Yb 0.10 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in the beaker, 4.15 mL of zirconium n-butoxide and weighing 0.3875 g of ytterbium chloride are measured and mixed in the beaker. All other parts are the same.

[0061] Comparative Example 6: Zr 0.80Yb 0.20 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, the method is to measure 3.70 mL of zirconium n-butoxide and weigh 0.7750 g of ytterbium chloride and mix them in a beaker. All other steps are the same.

[0062] Comparative Example 7: Zr 0.70 Yb 0.30 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in the beaker, 3.20 mL of zirconium n-butoxide and weighing 1.1625 g of ytterbium chloride are measured and mixed in the beaker. All other parts are the same.

[0063] Comparative Example 8: Zr 0.60 Yb 0.40 The preparation process of O2 oxide upconversion phosphor is as follows: The only difference from Example 1 is that instead of measuring 4.53 mL of zirconium n-butoxide, weighing 0.0387 g of ytterbium chloride and 3.8424 g of anhydrous citric acid and mixing them in a beaker, the method is to measure 2.75 mL of zirconium n-butoxide and weigh 1.5500 g of ytterbium chloride and mix them in a beaker. All other steps are the same.

[0064] The structure, morphology, and properties of the materials prepared in Examples 1-14 and Comparative Examples 1-8 are shown in the appendix. Figures 1-9 and Table 1: from Figure 1 It can be seen that, compared with the monoclinic phase PDF card 83-0396, the tetragonal phase PDF standard card 79-1767, and the cubic phase PDF standard card 81-1551 of ZrO2, with the increase of Yb 3+ With increasing doping concentration, the sample gradually transforms from a coexistence of monoclinic and tetragonal phases to a tetragonal phase, and then from a tetragonal phase to a cubic phase. Specifically: when the Yb doping concentration (referring to the Yb / (Zr+Yb) molar ratio) is 1%~2%, the monoclinic and tetragonal phases coexist; when the Yb doping concentration is greater than 2% but not exceeding 6%, it is a tetragonal phase; and when the Yb doping concentration is greater than 6% but not exceeding 40%, it is a cubic phase. The diffraction peaks of ZrO2 and ytterbium oxide are absent from the spectra, indicating that Yb... 3+ Successfully doped into the ZrO2 lattice, with no other impurity phases generated.

[0065] like Figure 2As shown, compared with the monoclinic phase PDF card 83-0396, tetragonal phase PDF standard card 79-1767, and cubic phase PDF standard card 81-1551 of ZrO2, with Yb 3+ With increasing doping concentration, the sample gradually transforms from a coexistence of monoclinic and tetragonal phases to a cubic phase. During this transformation, the proportion of the monoclinic phase continuously decreases. Specifically, when the Yb doping concentration is 1%–6%, the monoclinic and tetragonal phases coexist; when the Yb doping concentration is greater than 6% but does not exceed 40%, the phase is cubic. The diffraction patterns show no ytterbium oxide diffraction peaks except for those of ZrO2, indicating that Yb… 3+ Successfully doped into the ZrO2 lattice, with no other impurity phases generated.

[0066] Depend on Figure 1 and Figure 2 The results show that the addition of citric acid is beneficial to stabilizing the tetragonal and cubic phases.

[0067] like Figure 3 As shown, the sample particles of Example 7 are covered with tiny pores with a diameter of approximately 120 nm.

[0068] like Figure 4 As shown, the sample particles in Example 8 are covered with large pores, with a pore size of approximately 776 nm, which is similar to... Figure 3 The comparison shows that the Yb doping concentration can control the pore size.

[0069] like Figure 5 As shown, the sample particles of Example 10 are covered with large pores, with a pore size of approximately 539 nm.

[0070] like Figure 6 As shown, it can be seen that the sample particles of Comparative Example 8 have smooth surfaces and no pores.

[0071] like Figure 7 As shown, at a power density of 400 W / cm² 2 and 500 W / cm 2 Under laser excitation, the photoluminescence intensity of Example 7 is greater than that of Comparative Example 7.

[0072] like Figure 8 As shown, at a power density of 400 W / cm² 2 and 500 W / cm 2 Under laser excitation, the photoluminescence intensity of Example 8 is greater than that of Comparative Example 8.

[0073] from Figure 7 and Figure 8The test results show that the upconversion white light emission intensity of porous zirconia is higher than that of the corresponding non-porous zirconia. The possible reasons are: 1) The porous morphology reduces the thermal conductivity of zirconia, which is conducive to the upconversion of thermal radiation to white light emission; 2) The increased surface porosity increases the number of emitting sites, thereby further increasing the white light emission intensity.

[0074] like Figure 9 As shown, at a power density of 500 W / cm² 2 Under laser excitation, the photoluminescence intensity of Example 14 is greater, indicating that the addition of rare earth elements Er and Tm can significantly enhance upconversion white light emission.

[0075] Table 1 shows the doping and morphology of Examples 1-14 and Comparative Examples 1-8.

[0076] Table 1 As shown in Table 1, by comparing the morphology of Examples 7, 8 and Comparative Examples 7 and 8, it can be seen that citric acid is a necessary condition for the formation of surface pores. Furthermore, by comparing the morphology of Examples 5, 6 and 7 and 8, it can be seen that a high Yb doping concentration is a necessary condition for the formation of surface pores.

[0077] This invention obtains surface porous oxide phosphors by adding citric acid and increasing the rare earth ion doping concentration in a sol-gel method. To the inventor's knowledge, this method and the surface porous oxides prepared are the first publicly reported method.

[0078] Furthermore, it should be understood that after reading the above description of the present invention, those skilled in the art can make various alterations or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A porous upconversion white light emitting oxide, characterized in that, The chemical formula is Zr 1-x-y Yb x Re y O2, where: Re is one or more of Er, Ho, Tm, x and y represent atomic ratios, and 0.2 < x ≤ 0.

4. Further, 0.3 ≤ x ≤ 0.

4. Still further, 0.3 < x ≤ 0.4, and 0 ≤ y ≤ 0.

1.

2. The porous upconversion white light emitting oxide according to claim 1, characterized in that, The porous upconversion white light emitting oxide has a cubic phase.

3. The porous upconversion white light emitting oxide according to claim 1, characterized in that, The particle size distribution of the porous upconversion white light emitting oxide has a range of 0.2 to 100 μm.

4. The porous upconversion white light emitting oxide according to claim 1, characterized in that, The average pore size of the porous upconversion white light emitting oxide has a surface diameter of 0.02~3 μm.

5. The method for preparing a surface-porous upconversion white light-emitting oxide according to any one of claims 1 to 4, characterized in that, The sol-gel method includes: mixing Zr precursor, Yb precursor, anhydrous ethanol and acid, and optionally adding Re precursor, and heating and stirring until a dry gel is obtained. The dry gel is further dried and then calcined to obtain the surface porous upconversion white light emitting oxide. The acids include one or more of acetic acid, hydrochloric acid, sulfuric acid, nitric acid, and citric acid.

6. The preparation method according to claim 5, characterized in that, Zr precursor, Yb precursor, and Re precursor each independently include one or more of the following: nitrate, halide, carbonate, acetate, and organic salt.

7. The preparation method according to claim 5, characterized in that, The ratio of the molar amount of citric acid to the total molar amount of metal ions is 0.5 to 4:1, preferably 1 to 3:1, and more preferably 2:

1. The total molar amount of metal ions refers to the total molar amount of Zr ions, Yb ions, and selectively added Re ions.

8. The preparation method according to claim 5, characterized in that, The heating and stirring temperature is 60~200 ℃, preferably 120~200 ℃; The heating and stirring time is 1 to 12 hours, preferably 4 to 8 hours; The drying temperature is 60~250 ℃, preferably 70~100 ℃; The drying time is 1 to 24 hours, preferably 8 to 14 hours; The calcination temperature is 600~1600 ℃, preferably 700~1100 ℃; The heating rate of the calcination is 1~15 ℃ / min, preferably 5~10 ℃ / min; The calcination time is 3 to 24 hours, preferably 5 to 10 hours.

9. The preparation method according to claim 5, characterized in that, The preparation method also includes cooling in the furnace after calcination.

10. The application of the surface porous upconversion white light emitting oxide according to any one of claims 1 to 4 in luminescent materials.

Images