Rare earth doped upconversion single near-infrared luminescent scandium molybdate material and preparation method thereof

Abstract

The invention discloses a rare earth doped upconversion single near-infrared luminescent scandium molybdate material and a preparation method thereof, and belongs to the technical field of luminescent materials. The structural formula of the up-conversion near-infrared luminescent material provided by the invention is (Sc < 1-x-y > Yb < x > Er < y >) < 2 > Mo < 3 > O < 12 >, x is equal to 0.1 to 0.3, and y is equal to 0.005 to 0.04. The preparation method is a high-temperature solid-phase method and comprises the following steps: weighing scandium oxide, ytterbium oxide, erbium oxide and molybdenum oxide as raw materials according to stoichiometry, uniformly mixing with absolute ethyl alcohol, drying, sufficiently grinding, pressing into sheets, presintering at 800 DEG C in a muffle furnace, heating to 1100 DEG C, and carrying out high-temperature solid-phase sintering. The prepared rare earth doped scandium molybdate up-conversion luminescent material has excellent near-infrared luminescence performance, and the regulation and control of the luminescence intensity can be realized by adjusting the rare earth doping proportion. Meanwhile, the preparation method is good in repeatability, high in yield, simple and feasible in preparation process, more energy-saving and environment-friendly in preparation process and suitable for industrial popularization.

Description

Technical Field

[0001] The invention belongs to the technical field of luminescent materials, and in particular relates to a rare earth doped up-conversion single near-infrared luminescent scandium molybdate material and a preparation method thereof. Background Art

[0002] Over the years, many researchers at home and abroad have made unprecedented achievements in the study of alkaline earth metals and rare earth oxides. They have studied the structure and optical properties of these materials in detail in rare earth doped luminescent materials with borates, phosphates, silicates, etc. as matrices, and have achieved rich research results. Among them, molybdate, as an inorganic compound, has a unique phase and variable morphology. Its good chemical stability and high quantum yield make it have good luminescence conditions, making it practically applied in many fields such as display lighting, temperature sensing and optoelectronic devices.

[0003] Common oxidation preparation methods include hydrothermal method, coprecipitation method and high temperature solid phase method. The basic process of hydrothermal method is Sc(NO 3 ) 3 ·H 2 O and Na 2 Mo 4 ·H 2 OWeigh the raw materials according to a certain stoichiometric ratio, dissolve them, stir them and mix them evenly, transfer them to a hydrothermal kettle for reaction, set the experimental parameters. After cooling and washing several times, put them in an oven to dry, and obtain Sc 2 Mo 3 O 12 The precursor is finally calcined at 800℃ for 2h, and the prepared material can be obtained after the furnace is cooled. The high-temperature solid phase method is to weigh the raw materials of scandium oxide, ytterbium oxide, erbium oxide and molybdenum oxide compounds, stir them mechanically to mix the precursor powders evenly, press the powders into sheets, and then calcine them at high temperature to obtain the molybdate product. In comparison, the high-temperature solid phase method has the advantages of simpler process, more controllable preparation process, short preparation cycle and high output.

[0004] Upconversion luminescence is an anti-Stokes radiation process. Upconversion luminescent materials can achieve the goal of emitting high-energy light when the material is excited by low-energy light. In other words, long-wavelength, low-frequency light excites short-wavelength, high-frequency light. At present, most of the preparation methods of upconversion luminescent materials are chemical synthesis, and these preparation methods have problems such as low yield, poor controllability, low repeatability, and high raw material costs. Usually, good rare earth doped upconversion matrix materials have the characteristics of low phonon energy and stable photochemical properties. For example, fluoride (NaYF 4 or NaGdF 4 However, oxides with high phonon energy also have high upconversion efficiency, such as (YVO 4or KLu(WO 4 ) 2 etc.) Good matrix doping Er 3+ As an activator and Yb with large absorption cross section 3+ As a sensitizer, it can generally excite visible light waves such as green and red. In addition, fluorescent materials that can emit up-converted single near-infrared light are very rare. It is worth noting that most materials based on molybdates have the characteristics of simple synthesis process, low cost, and high light conversion efficiency. At the same time, the trivalent scandium ion in scandium molybdate is more suitable as a matrix material because it is a rare earth-like and the outermost layer is closed. With the widespread application of luminescent materials, rare earth-doped scandium molybdate fluorescent materials have great potential research value.

[0005] In order to fully explore the potential of scandium molybdate in the field of luminescent materials, the present invention combines the advantages of scandium molybdate having certain optical properties and being prepared by a high-temperature solid-phase method, and proposes a scandium molybdate (Sc molybdate) doped with a certain proportion of ytterbium oxide and erbium oxide. 2 Mo 3 O 12 ) compound, which can be excited when irradiated with an infrared laser to achieve up-conversion of single near-infrared luminescence. Summary of the invention

[0006] In view of the technical problems in the above-mentioned prior art such as low yield, low controllability, low repeatability and high raw material cost of up-conversion luminescent materials, the present invention proposes a rare earth-doped scandium molybdate up-conversion material with good repeatability, high yield and simple preparation process and a preparation method thereof, providing new materials for the application of scandium molybdate in lighting, display and even biomedicine.

[0007] The technical solution adopted by the present invention is as follows:

[0008] A rare earth doped up-conversion single near-infrared luminescent scandium molybdate material, characterized in that the structural formula of the up-conversion luminescent material is: (Sc 1-x-y Yb x Er y ) 2 Mo 3 O 12 , where x=0.1~0.3, y=0.005~0.04.

[0009] A method for preparing a rare earth doped up-conversion single near-infrared luminescent scandium molybdate material, characterized in that it comprises the following steps:

[0010] Step 1: weigh scandium oxide, ytterbium oxide, erbium oxide and molybdenum oxide as raw materials according to the molar ratio of Sc, Yb, Er and Mo of 2(1-xy):2x:2y:3; wherein x=0.1-0.3, y=0.005-0.04;

[0011] Step 2: Put all the raw materials weighed in the first step into a beaker, add anhydrous ethanol, and stir the raw materials with a glass rod to mix them evenly to obtain a suspension;

[0012] Step 3: The suspension obtained in the second step is placed in a drying oven for 40 minutes to completely evaporate the anhydrous ethanol in the raw material;

[0013] Step 4: After drying, the raw materials are fully ground and pressed into round pieces;

[0014] Step 5: Place the pressed disc-shaped sample into a muffle furnace for sintering. First, sinter it at 800°C for 30 minutes, then raise the sintering temperature to 1100°C and sinter it for 240 minutes. After naturally cooling to room temperature, take out the sample and grind it into powder to obtain a rare earth-doped up-conversion single near-infrared luminescent scandium molybdate material.

[0015] Furthermore, the concentration of the suspension obtained in the second step is 0.13-0.15 g of raw material per ml of anhydrous ethanol;

[0016] Furthermore, in the third step, the drying temperature should be set between 40 and 75° C. to prevent the anhydrous ethanol from boiling and causing the suspension to splash out, and the drying time is set to 1 to 2 hours to ensure that the anhydrous ethanol in the raw material is completely evaporated.

[0017] The beneficial effects of the present invention are:

[0018] The rare earth doped up-conversion single near-infrared luminescent scandium molybdate material obtained by the present invention has excellent luminescent properties, and the regulation of luminescent intensity can be achieved by adjusting the ratio of rare earth doping. More importantly, the preparation method of the up-conversion luminescent material has good repeatability, high yield, simple preparation process, and the preparation process is more energy-saving and environmentally friendly, which is suitable for industrial promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 for (Sc 0.99-x Yb x Er 0.01 ) 2 Mo 3 O 12 Powder X-ray diffraction spectra of the (x=0.1, 0.2, 0.3) series.

[0020] Figure 2 for (Sc 0.8-y Yb 0.2 Er y ) 2 Mo 3 O 12Powder X-ray diffraction spectra of the (y=0.005, 0.01, 0.02, 0.04) series.

[0021] Figure 3 for (Sc 0.99-x Yb x Er 0.01 ) 2 Mo 3 O 12 Up-conversion luminescence graph of the (x=0.1, 0.2, 0.3) series.

[0022] Figure 4 for (Sc 0.8-y Yb 0.2 Er y ) 2 Mo 3 O 12 (y=0.005, 0.01, 0.02, 0.04) series of up-conversion luminescence images.

[0023] Figure 5 (Sc) synthesized in Example 1 0.79 Yb 0.2 Er 0.01 ) 2 Mo 3 O 12 Powder X-ray diffraction spectrum.

[0024] Figure 6 (Sc) synthesized in Example 1 0.79 Yb 0.2 Er 0.01 ) 2 Mo 3 O 12 The powder is excited by a 980nm laser to produce a graph showing the relationship between wavelength and luminescence intensity.

[0025] Figure 7 (Sc) synthesized in Example 2 0.69 Yb 0.3 Er 0.01 ) 2 Mo 3 O 12 Powder X-ray diffraction spectrum.

[0026] Figure 8 (Sc) synthesized in Example 2 0.69 Yb 0.3 Er 0.01 ) 2 Mo 3 O 12 The powder is excited by a 980nm laser to produce a graph showing the relationship between wavelength and luminescence intensity.

[0027] Fig. 9 (Sc) synthesized in Example 3 0.76 Yb 0.2 Er 0.04 ) 2 Mo 3 O 12 Powder X-ray diffraction spectrum.

[0028] Fig.10 (Sc) synthesized in Example 3 0.76 Yb 0.2 Er 0.04 ) 2 Mo 3 O 12 The powder is excited by a 980nm laser to produce a graph showing the relationship between wavelength and luminescence intensity. DETAILED DESCRIPTION

[0029] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in conjunction with the following specific embodiments and with reference to the accompanying drawings.

[0030] Embodiment 1:

[0031] The prepared product in this embodiment is (Sc 0.79 Yb 0.2 Er 0.01 ) 2 Mo 3 O 12 Powder, prepared as follows:

[0032] According to the molar ratio of Sc, Yb, Er, and Mo of 1.58:0.4:0.3:0.02:3, calculate the mass of 0.00183 mol of scandium oxide, 0.00046 mol of ytterbium oxide, 0.00002 mol of erbium oxide, and 0.00695 mol of molybdenum oxide, and weigh them accurately. Put all the raw materials into a beaker, add 25 ml of anhydrous ethanol as a dispersion medium, stir with a glass rod to make the suspension fully uniform, put the beaker into a drying oven after standing for 40 minutes, set the drying temperature to 65°C, record the starting drying time, and dry for 2 hours to completely evaporate the water vapor and anhydrous ethanol in the sample. Take out the beaker, divide the precursor powder into 4 parts, press the divided sample powder into discs with a tablet press, and keep the pressure gauge at 12Mpa for about ten minutes to ensure that the internal and external forces of the sample are consistent. The pressed sample was placed in a muffle furnace, and the heating curve of the muffle furnace was set to maintain at 800 °C for 30 minutes, and then raised to 1100 °C for 240 minutes to allow the precursor to fully react to generate (Sc 0.79 Yb 0.2 Er 0.01 ) 2 Mo 3 O 12After the muffle furnace runs through the set sintering program and naturally cools to room temperature, the sample is taken out and fully ground into powder to obtain a rare earth doped up-conversion single near-infrared luminescent scandium molybdate material.

[0033] Figure 5 The X-ray diffraction results show that the X-ray diffraction pattern is consistent with the Sc 2 Mo 3 O 12 (PDF card number is 073-0010) diffraction spectrum is consistent, indicating that the sintered product is orthorhombic phase Sc 2 Mo 3 O 12 .

[0034] Depend on Figure 6 The wavelength-luminescence intensity relationship diagram shows that the Sc doped with ytterbium oxide and erbium oxide prepared by the present invention 2 Mo 3 O 12 When excited, the powder can emit light with a wavelength in the near-infrared range, and the luminescence intensity is maximum at the near-infrared wavelength of 829nm.

[0035] Embodiment 2:

[0036] The prepared product in this embodiment is (Sc 0.69 Yb 0.3 Er 0.01 ) 2 Mo 3 O 12 The difference between this embodiment and embodiment 1 is that the content of scandium oxide is adjusted from 0.00182 mol to 0.00159 mol, and the content of ytterbium oxide is adjusted from 0.00046 mol to 0.00069 mol, and the other steps remain unchanged. The purpose is to verify the stability of the present invention in adjusting the raw material composition and the production process after adjusting the proportion of rare earth oxides.

[0037] Figure 7 The X-ray diffraction results show that the crystal structure of the sample conforms to Sc 2 Mo 3 O 12 Crystal structure (PDF card number 073-0010).

[0038] Depend on Figure 8 From the wavelength-luminous intensity relationship diagram, we can see that (Sc 0.69 Yb 0.3 Er 0.01 ) 2 Mo 3 O 12The powder is also excited by a 980nm infrared laser, and the luminescence intensity at the near-infrared wavelength of 829nm is slightly weaker than that of Example 1.

[0039] Embodiment 3:

[0040] The prepared product in this embodiment is (Sc 0.76 Yb 0.2 Er 0.04 ) 2 Mo 3 O 12 Materials, the difference between this embodiment and embodiment 1 is that the content of scandium oxide is adjusted from 0.00182 mol to 0.00175 mol, the content of erbium oxide is adjusted from 0.00002 mol to 0.00009 mol, and the other steps remain unchanged. The purpose is also to verify the stability of this synthesis process after adjusting the proportion of rare earth oxides.

[0041] Fig. 9 The X-ray diffraction results show that the crystal structure of the sample conforms to Sc 2 Mo 3 O 12 Crystal structure (PDF card number 073-0010).

[0042] Depend on Fig.10 From the wavelength-luminous intensity relationship diagram, we can see that (Sc 0.76 Yb 0.2 Er 0.04 ) 2 Mo 3 O 12 When the material is excited by a 980nm infrared laser, the near-infrared light wavelength of 829nm has a luminescence intensity. Compared with Examples 1 and 2, the near-infrared luminescence is the lowest.

Claims

1. A rare earth doped up-conversion single near-infrared luminescent scandium molybdate material, characterized in that: The structural formula of the up-conversion luminescent material is: 1-x-y Yb x Er y )2Mo3O 12 , where x=0.1~0.3, y=0.005~0.

04.

2. A method for preparing a rare earth doped up-conversion single near-infrared luminescent scandium molybdate material, characterized in that: The following steps are involved: Step 1: weigh scandium oxide, ytterbium oxide, erbium oxide and molybdenum oxide as raw materials according to the molar ratio of Sc, Yb, Er and Mo of 2(1-xy):2x:2y:3; wherein x=0.1-0.3, y=0.005-0.04; Step 2: adding anhydrous ethanol to the raw materials weighed in the first step, and mixing evenly to obtain a suspension; Step 3: Let the suspension stand for 40 minutes and then dry it to completely evaporate the anhydrous ethanol in the raw material; Step 4: Grind the raw materials dried in step 3 and press them into round pieces; Step 5: Place the disc-shaped sample into a muffle furnace, sinter it at 800°C for 30 minutes, then raise the temperature to 1100°C and sinter it for 240 minutes. After naturally cooling to room temperature, take out the sample and grind it into powder to obtain a rare earth-doped scandium molybdate upconversion luminescent material.

3. The method for preparing the rare earth doped scandium molybdate upconversion luminescent material according to claim 2, characterized in that: The concentration of the suspension in the second step is 0.13-0.15 g of raw material per ml of anhydrous ethanol.

4. The method for preparing the rare earth doped scandium molybdate upconversion luminescent material according to claim 2, characterized in that: The drying temperature in the third step is 40-75° C., and the drying time is 1-2 hours.

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