Upconversion nanomaterial with red light emission and preparation method thereof
By adopting a core-shell-shell structure in LiErF4-based upconversion nanomaterials and using the cross relaxation effect of Er3+ and Ce3+, the energy loss problem of LiErF4-based nanomaterials during the upconversion process is solved, and the intensity of red light emission is increased, which is suitable for applications such as biofluorescence imaging.
Patent Information
- Application Number
- CN202311670615.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-12-07
- Publication Date
- 2025-08-12
- Estimated Expiration
- 2043-12-07
AI Technical Summary
The existing LiErF4-based upconversion nanomaterials have energy loss problems during the upconversion process, especially in the presence of Yb3+, which leads to a decrease in luminous intensity, limiting its application in the fields of biofluorescence imaging.
Using the core-shell-shell structure design, the chemical formula of LiErF4:0.5%Tm@LiYF4:50%Yb,x%Er,y%Ce@LiYF4, where Er3+ is an energy collector, uses the cross relaxation effect of Er3+ and Ce3+ to transmit energy back to Yb3+, reduces energy loss, and realizes red light emission.
It effectively improves the intensity and efficiency of red light emission, reduces energy loss, is suitable for large-scale production, is low in cost, and is suitable for biofluorescence imaging and other fields.
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Figure CN117660009B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of luminescent materials, and in particular relates to an up-conversion nanomaterial with red light emission and a preparation method thereof. Background Art
[0002] Upconversion luminescent materials are a class of luminescent materials that follow the Anti-Stokes process. These materials absorb long-wavelength light through multiphoton absorption and transfer energy to shorter-wavelength light, thereby achieving upconversion luminescence. Compared with traditional fluorescent materials, rare earth upconversion luminescent materials have excellent properties such as large anti-Stokes shift, low biotoxicity, narrow emission spectrum, long luminescence lifetime, and high luminescence intensity. Therefore, they have broad application prospects in anti-counterfeiting, solar cells, display devices, solid-state lasers, biomedical fields, and especially bioimaging. Compared with short-wavelength green and blue light, long-wavelength red light has deeper penetration into biological tissues and is therefore known as the "visible light biological window." Therefore, obtaining upconversion luminescent materials with red light emission is of great significance for biological applications.
[0003] In recent years, Er-based upconversion nanomaterials have become one of the research hotspots in the field of luminescent materials due to their high luminescence efficiency, good photostability, and high biocompatibility. Compared with other Er-based upconversion materials, LiErF4-based upconversion luminescent materials have better crystallization properties due to their spinel structure, and the luminescence peak of LiErF4 in the visible light region is narrower and sharper, which makes it have higher luminescence efficiency and longer life. However, due to the problems such as energy loss in the upconversion process, the luminescence intensity decreases, especially when Yb is present in the system. 3+ When the spontaneous radiation energy is lost.
[0004] Therefore, the development of a LiErF4-based upconversion nanomaterial with red light emission is of great significance for the application of bioluminescence imaging. Summary of the Invention
[0005] The purpose of the present invention is to overcome the problems existing in the above-mentioned prior art and to provide an up-conversion nanomaterial with red light emission and a preparation method thereof.
[0006] The present invention is achieved through the following technical solutions:
[0007] In a first aspect, the present invention provides an upconversion nanomaterial with red light emission, which has LiErF4:0.5% Tm as a core layer, and a LiYF4:50% Yb, x% Er, y% Ce shell layer and a LiYF4 passivation layer coated on the outside of the core layer in sequence; the chemical formula of the upconversion nanomaterial with red light emission is LiErF4:0.5% Tm@LiYF4:50% Yb, x% Er, y% Ce@LiYF4; wherein 0≤x≤15, 0≤y≤4.
[0008] The upconversion nanomaterial of the present invention has a core-shell-shell structure, with LiErF4:0.5% Tm as the core layer, LiYF4:50% Yb, x% Er, y% Ce as the first shell layer, and LiYF4 passivation layer as the outermost second shell layer; in this structure, the first shell layer is doped with an appropriate concentration of Er 3+ ,Ce 3+ With Yb 3+ , and Er 3+ As an energy harvester, it absorbs energy from the first shell Yb 3+ The spontaneous radiation energy is then used to 3+ With Ce 3+ The cross-relaxation effect transfers energy back to Yb 3+ , and transmitted back to the nuclear layer, effectively reducing energy loss and thus obtaining red light emission.
[0009] In the present invention, x can be any one of 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15, or an intermediate value between any two thereof; preferably, x is any one of 0, 2, 5, 8, 10, and 15.
[0010] In the present invention, y can be any one of 0, 0.2, 2, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4 or an intermediate value between any two of them; preferably, y is any one of 0, 0.2, 0.5, 1, 1.5, 2, 3, 4.
[0011] The percentages shown in the chemical formulas of the present invention refer to molar percentages.
[0012] More preferably, 0<x≤15, 0<y≤4; further, x=5, y=1.
[0013] When x% is 5% and y% is 1%, Er 3+ Yb 3+ The energy absorption efficiency reaches the maximum, and under the excitation of 980nm near-infrared light, its red light emission intensity is effectively improved compared with that of the undoped state.
[0014] Preferably, the average particle size of the up-conversion nanomaterial with red light emission is 22.96 nm to 37.36 nm.
[0015] In a second aspect, the present invention provides a method for preparing the upconversion nanomaterial having red light emission, comprising the following steps:
[0016] (1) oleic acid, octadecene, an erbium salt solution, and a thulium salt solution are uniformly mixed, heated to remove moisture, and heated to react to form a rare earth-oleic acid chelate. After cooling, a methanol solution of lithium hydroxide and a methanol solution of ammonium fluoride are added and stirred. The methanol is heated to remove methanol, and then reacted at high temperature under an inert atmosphere to obtain core layer LiErF4:0.5%Tm nanoparticles;
[0017] (2) After oleic acid, octadecene, yttrium-oleic acid chelate, ytterbium-oleic acid chelate, erbium-oleic acid chelate and cerium-oleic acid chelate are uniformly mixed, the core layer LiErF4:0.5%Tm nanoparticles obtained in step (1) are added, and then a methanol solution of lithium hydroxide and a methanol solution of ammonium fluoride are added and stirred, the temperature is increased to remove the methanol, and then the mixture is reacted at high temperature under an inert atmosphere to obtain a LiErF4:0.5%Tm@LiYF4:50%Yb,x%Er,y%Ce core-shell structure nanoparticle solution;
[0018] (3) adding yttrium-oleic acid chelate to the solution obtained in step (2), mixing uniformly, then adding a methanol solution of lithium hydroxide and a methanol solution of ammonium fluoride and stirring, heating to remove methanol, and then reacting at a high temperature under an inert atmosphere to obtain the upconversion nanomaterial having red light emission.
[0019] In the preparation method of the present invention, oleic acid, octadecene, rare earth salt, rare earth element-oleic acid chelate, lithium hydroxide and ammonium fluoride are subjected to a coprecipitation reaction to prepare the upconversion nanomaterial. The preparation process is simple and easy to operate, low in cost, short in cycle, and suitable for mass production.
[0020] Preferably, in step (1), the bait salt comprises bait chloride, and the thulium salt comprises thulium chloride.
[0021] The solvent of the bait salt solution and the thulium salt solution is water.
[0022] The core layer LiErF4:0.5%Tm nanoparticles obtained in step (1) of the present invention and the upconversion nanomaterial with red light emission obtained in step (3) are preferably stored in cyclohexane for use.
[0023] Preferably, in step (1), the volume ratio of oleic acid to octadecene is (0.65-0.85):1.
[0024] More preferably, in step (1), the volume ratio of oleic acid to octadecene is 0.75:1.
[0025] Preferably, in step (1), the concentration of the bait salt solution is 0.4 mol·L -1 -0.6 mol·L -1 The concentration of the thulium salt solution is 0.08 mol·L -1 -0.12 mol·L -1 .
[0026] More preferably, in step (1), the concentration of the bait salt solution is 0.5 mol·L -1 The concentration of the thulium salt solution is 0.1 mol·L -1 .
[0027] Preferably, in step (1), the volume ratio of the oleic acid to the bait salt solution is 300:(38.8-40.8).
[0028] More preferably, in step (1), the volume ratio of the oleic acid to the bait salt solution is 300:39.8.
[0029] Preferably, in step (1), the volume ratio of oleic acid to thulium salt solution is 300:(0.5-1.5).
[0030] More preferably, in step (1), the volume ratio of the oleic acid to the thulium salt solution is 300:1.
[0031] Preferably, the temperature for heating to remove moisture in step (1) is 90°C-110°C.
[0032] More preferably, the temperature for removing moisture in step (1) is 105°C.
[0033] Preferably, in step (1), the heating reaction temperature is 145° C.-155° C., and the time is 1 h-1.5 h.
[0034] More preferably, in step (1), the heating reaction temperature is 150° C. and the time is 1.2 h.
[0035] Preferably, in the steps (1), (2) and (3), the concentration of lithium hydroxide in the methanol solution of lithium hydroxide is 0.2 mol / L-0.8 mol / L.
[0036] More preferably, in the steps (1), (2) and (3), the concentration of lithium hydroxide in the methanol solution of lithium hydroxide is 0.5 mol / L.
[0037] Preferably, in the steps (1), (2) and (3), the concentration of ammonium fluoride in the methanol solution of ammonium fluoride is 0.5 mol / L-1 mol / L.
[0038] More preferably, in the steps (1), (2) and (3), the concentration of ammonium fluoride in the methanol solution of ammonium fluoride is 0.8 mol / L.
[0039] Preferably, in step (1), step (2) and step (3), the volume ratio of the methanol solution of lithium hydroxide to the methanol solution of ammonium fluoride is (0.8-1.2):1.
[0040] More preferably, in step (1), step (2) and step (3), the volume ratio of the methanol solution of lithium hydroxide to the methanol solution of ammonium fluoride is 1:1.
[0041] Preferably, in step (1), the volume ratio of the bait salt solution to the methanol solution of lithium hydroxide is (37.8-41.8):100.
[0042] More preferably, in step (1), the volume ratio of the bait salt solution to the methanol solution of lithium hydroxide is 39.8:100.
[0043] Preferably, in step (1), the volume ratio of the thulium salt solution to the methanol solution of lithium hydroxide is (0.8-1.2):100.
[0044] More preferably, in step (1), the volume ratio of the thulium salt solution to the methanol solution of lithium hydroxide is 1:100.
[0045] Preferably, in step (1), the volume ratio of the bait salt solution to the methanol solution of ammonium fluoride is (37.8-41.8):100.
[0046] More preferably, in step (1), the volume ratio of the bait salt solution to the methanol solution of ammonium fluoride is 39.8:100.
[0047] Preferably, in step (1), the volume ratio of the thulium salt solution to the methanol solution of ammonium fluoride is (0.8-1.2):100.
[0048] More preferably, in step (1), the volume ratio of the thulium salt solution to the methanol solution of ammonium fluoride is 1:100.
[0049] Preferably, in step (2), the preparation method of the yttrium-oleic acid chelate (or ytterbium-oleic acid chelate or erbium-oleic acid chelate or cerium-oleic acid chelate) comprises the following steps: uniformly mixing oleic acid, octadecene, and a yttrium salt solution (or ytterbium salt solution or erbium salt solution or cerium salt solution), heating to remove moisture, and heating the mixture to react to generate the corresponding yttrium-oleic acid chelate (or ytterbium-oleic acid chelate or erbium-oleic acid chelate or cerium-oleic acid chelate).
[0050] The preparation method of the yttrium-oleic acid chelate, ytterbium-oleic acid chelate, erbium-oleic acid chelate, and cerium-oleic acid chelate described in step (2) of the present application is basically the same as the preparation method of the rare earth-oleic acid chelate in step (1).
[0051] Preferably, in step (2), the volume ratio of oleic acid to octadecene is (1.8-2.2):3.
[0052] More preferably, in step (2), the volume ratio of oleic acid to octadecene is 2:3.
[0053] Preferably, in step (2), the concentration of the yttrium-oleic acid chelate is 0.035 mol·L -1 -0.045 mol·L -1 The concentration of the ytterbium-oleic acid chelate is 0.035 mol·L -1 -0.045 mol·L -1 The concentration of the erbium-oleic acid chelate is 0.035 mol·L -1 -0.045 mol·L -1 The concentration of the cerium-oleic acid chelate is 0.002 mol·L -1 -0.006mol·L -1 .
[0054] More preferably, in step (2), the concentration of the yttrium-oleic acid chelate is 0.04 mol·L -1 The concentration of the ytterbium-oleic acid chelate is 0.04 mol·L -1 The concentration of the erbium-oleic acid chelate is 0.04 mol·L -1 The concentration of the cerium-oleic acid chelate is 0.004 mol·L -1 .
[0055] Preferably, in step (2), the volume ratio of oleic acid to yttrium-oleic acid chelate is 100:(10.25-11.25).
[0056] More preferably, in step (2), the volume ratio of oleic acid to yttrium-oleic acid chelate is 100:11.
[0057] Preferably, in step (2), the volume ratio of oleic acid to ytterbium-oleic acid chelate is 10:(1-1.5).
[0058] More preferably, in step (2), the volume ratio of oleic acid to ytterbium-oleic acid chelate is 10:1.25.
[0059] Preferably, in step (2), the volume ratio of oleic acid to erbium-oleic acid chelate is 100:(0-3.75).
[0060] More preferably, in step (2), the volume ratio of oleic acid to erbium-oleic acid chelate is 100:(0.5-3.75); further, in step (2), the volume ratio of oleic acid to erbium-oleic acid chelate is 100:1.25.
[0061] Preferably, in step (2), the volume ratio of oleic acid to cerium-oleic acid chelate is 10:(0-1).
[0062] More preferably, in step (2), the volume ratio of oleic acid to cerium-oleic acid chelate is 10:(0.05-1); further, in step (2), the volume ratio of oleic acid to cerium-oleic acid chelate is 10:0.25.
[0063] Preferably, in step (2), the molar ratio of the core layer LiErF4:0.5%Tm nanoparticles to the yttrium-oleic acid chelate is 1:(0.41-0.45).
[0064] More preferably, in step (2), the molar ratio of the core layer LiErF4:0.5%Tm nanoparticles to the yttrium-oleic acid chelate is 1:0.44.
[0065] Preferably, in step (2), the molar ratio of the core layer LiErF4:0.5%Tm nanoparticles to the ytterbium-oleic acid chelate is 1:(0.4-0.6).
[0066] More preferably, in step (2), the molar ratio of the core layer LiErF4:0.5%Tm nanoparticles to the ytterbium-oleic acid chelate is 1:0.5.
[0067] Preferably, in step (2), the molar ratio of the core layer LiErF4:0.5%Tm nanoparticles to the erbium-oleic acid chelate is 1:(0.03-0.07).
[0068] More preferably, in step (2), the molar ratio of the core layer LiErF4:0.5%Tm nanoparticles to the erbium-oleic acid chelate is 1:0.05.
[0069] Preferably, in step (2), the molar ratio of the core layer LiErF4:0.5%Tm nanoparticles to the cerium-oleic acid chelate is 1:(0.008-0.012).
[0070] More preferably, in step (2), the molar ratio of the core layer LiErF4:0.5%Tm nanoparticles to the cerium-oleic acid chelate is 1:0.01.
[0071] Preferably, in step (2), the volume ratio of the yttrium-oleic acid chelate to the methanol solution of lithium hydroxide is (2.05-2.25):1.
[0072] More preferably, in step (2), the volume ratio of the yttrium-oleic acid chelate to the methanol solution of lithium hydroxide is 2.2:1.
[0073] Preferably, in step (2), the volume ratio of the ytterbium-oleic acid chelate to the methanol solution of lithium hydroxide is (2-3):1.
[0074] More preferably, in step (2), the volume ratio of the ytterbium-oleic acid chelate to the methanol solution of lithium hydroxide is 2.5:1.
[0075] Preferably, in step (2), the volume ratio of the erbium-oleic acid chelate to the methanol solution of lithium hydroxide is (0.05-0.375):1.
[0076] More preferably, in step (2), the volume ratio of the erbium-oleic acid chelate to the methanol solution of lithium hydroxide is 0.25:1.
[0077] Preferably, in step (2), the volume ratio of the cerium-oleic acid chelate to the methanol solution of lithium hydroxide is (0.1-2):1.
[0078] More preferably, in step (2), the volume ratio of the cerium-oleic acid chelate to the methanol solution of lithium hydroxide is 0.5:1.
[0079] Preferably, in step (2), the volume ratio of the yttrium-oleic acid chelate to the methanol solution of ammonium fluoride is (2.05-2.25):1.
[0080] More preferably, in step (2), the volume ratio of the yttrium-oleic acid chelate to the methanol solution of ammonium fluoride is 2.2:1.
[0081] Preferably, in step (2), the volume ratio of the ytterbium-oleic acid chelate to the methanol solution of ammonium fluoride is (2-3):1.
[0082] More preferably, in step (2), the volume ratio of the ytterbium-oleic acid chelate to the methanol solution of ammonium fluoride is 2.5:1.
[0083] Preferably, in step (2), the volume ratio of the erbium-oleic acid chelate to the methanol solution of ammonium fluoride is (0.05-0.375):1.
[0084] More preferably, in step (2), the volume ratio of the erbium-oleic acid chelate to the methanol solution of ammonium fluoride is 0.25:1.
[0085] Preferably, in step (2), the volume ratio of the cerium-oleic acid chelate to the methanol solution of ammonium fluoride is (0.1-2):1.
[0086] More preferably, in step (2), the volume ratio of the cerium-oleic acid chelate to the methanol solution of ammonium fluoride is 0.5:1.
[0087] Preferably, in step (3), the concentration of the yttrium-oleic acid chelate is 0.035 mol·L -1 -0.045 mol·L -1 .
[0088] More preferably, in step (3), the concentration of the yttrium-oleic acid chelate is 0.04 mol·L -1 .
[0089] Preferably, in step (3), the molar ratio of the yttrium-oleic acid chelate to the core layer LiErF4:0.5%Tm nanoparticles in step (2) is (0.8-1.2):1.
[0090] More preferably, in step (3), the molar ratio of the yttrium-oleic acid chelate to the core layer LiErF4:0.5%Tm nanoparticles in step (2) is 1:1.
[0091] Preferably, in step (3), the volume ratio of the yttrium-oleic acid chelate to the methanol solution of lithium hydroxide is (4.5-5.5):1.
[0092] More preferably, in step (3), the volume ratio of the yttrium-oleic acid chelate to the methanol solution of lithium hydroxide is 5:1.
[0093] Preferably, in step (3), the volume ratio of the yttrium-oleic acid chelate to the methanol solution of ammonium fluoride is (4.5-5.5):1.
[0094] More preferably, in step (3), the volume ratio of the yttrium-oleic acid chelate to the methanol solution of ammonium fluoride is 5:1.
[0095] Preferably, in step (1), step (2) and step (3), the temperature for removing methanol by heating is 80°C-100°C.
[0096] More preferably, in the steps (1), (2) and (3), the temperature for removing methanol by heating is 90°C.
[0097] Preferably, in step (1), step (2) and step (3), the temperature of the high-temperature reaction is 280° C.-290° C., and the time is 0.9 h-1.1 h.
[0098] More preferably, in step (1), step (2) and step (3), the temperature of the high temperature reaction is 280° C. and the time is 1 hour.
[0099] Preferably, in step (1), step (2) and step (3), the inert atmosphere comprises nitrogen.
[0100] Preferably, in the steps (1) and (3), washing and centrifugation are further performed after the high temperature reaction.
[0101] Preferably, the washing method is washing with anhydrous ethanol; the centrifugation condition is centrifugation at 9000 rpm-11000 rpm for 8 min to 12 min, and a total of 2-4 centrifugations.
[0102] More preferably, the centrifugation condition is centrifugation at 10,000 rpm for 10 min, for a total of 3 times.
[0103] The present invention has the following beneficial effects:
[0104] (1) The upconversion nanomaterial prepared by the present invention has LiErF4:0.5%Tm as the core layer, and is coated with LiYF4:50%Yb,x%Er,y%Ce shell layer and LiYF4 passivation layer in sequence; the structure is designed with Er 3+ As an energy harvester, it absorbs energy from the first shell Yb 3+ The spontaneous radiation energy is then used to 3+ With Ce 3+ The cross-relaxation effect transfers energy back to Yb 3+ , and is transmitted back to the core, ultimately obtaining red light emission.
[0105] (2) In the preparation method of the present invention, oleic acid, octadecene, a rare earth salt (preferably a rare earth chloride), a rare earth element-oleic acid chelate, lithium hydroxide, and ammonium fluoride are subjected to a coprecipitation reaction to prepare the upconversion nanomaterial. This preparation process is simple and easy to operate, low in cost, and short in cycle, making it suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS
[0106] Figure 1 This is a transmission electron micrograph of the LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,1%Ce@LiYF4 upconversion nanomaterial prepared in Example 9;
[0107] Figure 2 Fluorescence spectra of upconversion nanomaterials of LiErF4:0.5%Tm@LiYF4:50%Yb,x%Er@LiYF4 (wherein x=0, 2, 5, 8, 10, 15) prepared in Examples 1-6;
[0108] Figure 3 Fluorescence spectra of upconversion nanomaterials LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,y%Ce@LiYF4 (wherein y=0, 0.2, 0.5, 1, 1.5, 2, 3, 4) prepared in Examples 3 and 7-13;
[0109] Figure 4 This is the upconversion energy level transition diagram of the LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,1%Ce@LiYF4 upconversion nanomaterial prepared in Example 9 under 980nm excitation. DETAILED DESCRIPTION
[0110] To better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments. Those skilled in the art should understand that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.
[0111] Unless otherwise specified, the experimental methods used in the examples are conventional methods; the materials, reagents, etc. used are all available from commercial sources unless otherwise specified.
[0112] The preparation methods of the yttrium-oleic acid chelate, ytterbium-oleic acid chelate, erbium-oleic acid chelate, and cerium-oleic acid chelate described in Examples 1-13 of the present application are as follows:
[0113] 1. A method for preparing a yttrium-oleic acid chelate, comprising the following steps:
[0114] (1) Prepare 50 mL of 0.04 mol YCl3 aqueous solution: First, calculate the mass of YCl3 weighed as 0.60672 g according to the formula: relative molecular mass of YCl3 (303.36) / 1000*50*0.04. Place the above mass of YCl3 in a 50 mL beaker, add deionized water to cover the YCl3, and stir until it is completely dissolved; use a rubber-tipped dropper to transfer the YCl3 aqueous solution in the beaker to a 50 mL volumetric flask and titrate to the 50 mL mark; place a rotor in the volumetric flask, stir thoroughly, and then transfer to a sample bottle for later use.
[0115] (2) Preparation of Y-OA chelate: 2 mL of the above-prepared YCl3 solution was placed in a three-necked flask containing 20 mL of oleic acid and 30 mL of octadecene. Nitrogen was introduced as a protective gas and the mixture was reacted at 105°C for 1.5 h to remove water vapor from the solution. The mixture was then heated to 150°C and reacted for 1.5 h. The resulting solution was the yttrium-oleic acid chelate.
[0116] 2. A method for preparing an ytterbium-oleic acid chelate, comprising the following steps:
[0117] (1) Prepare 50 mL of 0.04 mol YbCl3 aqueous solution: First, calculate the mass of YbCl3 weighed, which is 0.7748 g, according to the formula: relative molecular mass of YbCl3 (387.4) / 1000*50*0.04. Place the above mass of YbCl3 in a 50 mL beaker, add deionized water to cover the YbCl3, and stir until it is completely dissolved. Use a rubber-tipped dropper to transfer the YbCl3 aqueous solution in the beaker to a 50 mL volumetric flask and titrate to the 50 mL mark. Place a rotor in the volumetric flask, stir thoroughly, and then transfer to a sample bottle for later use.
[0118] (2) Preparation of Yb-OA chelate: 4 mL of the above-prepared YbCl3 solution was placed in a three-necked flask containing 20 mL of oleic acid and 30 mL of octadecene. Nitrogen was introduced as a protective gas and the mixture was reacted at 105°C for 1.5 h to remove water vapor from the solution. The mixture was then heated to 150°C and reacted for 1.5 h. The resulting solution was the ytterbium-oleic acid chelate.
[0119] 3. A method for preparing an erbium-oleic acid chelate, comprising the following steps:
[0120] (1) Prepare 50 mL of 0.5 mol ErCl3 aqueous solution: First, calculate the mass of ErCl3 weighed according to the formula: relative molecular mass of ErCl3 (273.62) / 1000*50*0.5 to obtain 6.8405 g. Place the above mass of ErCl3 in a 50 mL beaker, add deionized water to cover the ErCl3 and stir until it is completely dissolved; use a rubber-tipped dropper to transfer the ErCl3 aqueous solution in the beaker to a 50 mL volumetric flask and titrate to the 50 mL mark; place a rotor in the volumetric flask, stir thoroughly, and then transfer to a sample bottle for later use.
[0121] (2) Preparation of Er-OA chelate: 4 mL of the above-prepared ErCl3 solution was placed in a three-necked flask containing 20 mL of oleic acid and 30 mL of octadecene. Nitrogen was introduced as a protective gas and the mixture was reacted at 105°C for 1.5 h to remove water vapor from the solution. The mixture was then heated to 150°C and reacted for 1.5 h. The resulting solution was the erbium-oleic acid chelate.
[0122] 4. A method for preparing a cerium-oleic acid chelate, comprising the following steps:
[0123] (1) Prepare 50 mL of 0.1 mol CeCl3 aqueous solution: First, calculate the mass of CeCl3 weighed, which is 1.8629 g, according to the formula: relative molecular mass of CeCl3 (372.58) / 1000*50*0.1. Place the above mass of CeCl3 in a 50 mL beaker, add deionized water to cover the CeCl3, and stir until it is completely dissolved; use a rubber-tipped dropper to transfer the CeCl3 aqueous solution in the beaker to a 50 mL volumetric flask and titrate to the 50 mL mark; place a rotor in the volumetric flask, stir thoroughly, and then transfer to a sample bottle for later use.
[0124] (2) Preparation of Ce-OA chelate: 2 mL of the above-prepared CeCl3 solution was placed in a three-necked flask containing 20 mL of oleic acid and 30 mL of octadecene. Nitrogen was introduced as a protective gas and the mixture was reacted at 105°C for 1.5 h to remove water vapor from the solution. The mixture was then heated to 150°C and reacted for 1.5 h. The resulting solution was the cerium-oleic acid chelate.
[0125] Example 1
[0126] This embodiment provides a method for preparing a LiErF4:0.5%Tm@LiYF4:50%Yb@LiYF4 upconversion nanomaterial with red light emission, comprising the following steps:
[0127] (1) LiErF4:0.5% Tm core layer preparation: 15 mL of oleic acid and 20 mL of octadecene were added to a three-necked flask and stirred thoroughly to mix well. Then, 1.99 mL of 0.5 mol·L -1of erbium chloride solution and 0.05 mL of 0.1 mol·L -1 The thulium chloride solution was stirred thoroughly to mix evenly, then heated to 105°C to remove water from the solution, and then heated at 150°C for 1.5 hours to form a rare earth-oleic acid chelate;
[0128] Then naturally cooled to room temperature, 5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was added to the rare earth-oleic acid chelate prepared above and stirred uniformly. The temperature was raised to 90°C for 1 hour, and excess methanol was removed. The reaction was then carried out at 280°C under nitrogen for 1 hour. The reaction mixture was cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, twice to obtain a pink precipitate, i.e., the core layer LiErF4:0.5% Tm nanoparticles, which were stored in cyclohexane.
[0129] (2) LiYF4: 50% Yb shell coating: 10 mL of oleic acid and 15 mL of octadecene were stirred thoroughly in a three-necked flask and mixed evenly. Then, 1.25 mL of 0.04 mol·L -1 Yttrium-oleic acid chelate and 1.25mL of 0.04mol·L -1 Ytterbium-oleic acid chelate was mixed and stirred evenly, and the core layer LiErF4:0.5% Tm nanoparticles prepared in step (1) were added, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 The methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. Then, the reaction was carried out at 280°C for 1 hour under nitrogen protection and finally cooled naturally to obtain a reaction solution of LiErF4:0.5%Tm@LiYF4:50%Yb core-shell structured nanoparticles;
[0130] (3) LiYF4 passivation layer coating: take 2.5mL of 0.04mol·L -1 The yttrium-oleic acid chelate was added to the reaction solution after natural cooling in step (3), stirred evenly, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1A methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. The mixture was then reacted at 280°C for 1 hour under nitrogen protection. The reaction mixture was naturally cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, for a total of 2 centrifugations to obtain a precipitate, namely LiErF4:0.5% Tm@LiYF4:50% Yb@LiYF4 core-shell-shell structured nanoparticles, which were stored in cyclohexane to obtain the upconversion nanomaterial with red light emission of this embodiment.
[0131] Example 2
[0132] This embodiment provides a method for preparing a red-light-emitting upconversion nanomaterial LiErF4:0.5%Tm@LiYF4:50%Yb,2%Er@LiYF4, including the following steps:
[0133] (1) LiErF4:0.5% Tm core layer preparation: 15 mL of oleic acid and 20 mL of octadecene were added to a three-necked flask and stirred thoroughly to mix well. Then, 1.99 mL of 0.5 mol·L -1 of erbium chloride solution and 0.05 mL of 0.1 mol·L -1 The thulium chloride solution was stirred thoroughly and mixed evenly, then heated to 105°C to remove water from the solution, and then subjected to high temperature reaction at 150°C for 1.5 hours to generate rare earth-oleic acid chelate;
[0134] Then naturally cooled to room temperature, 5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was added to the rare earth-oleic acid chelate prepared above and stirred uniformly. The temperature was raised to 90°C for 1 hour, and excess methanol was removed. The reaction was then carried out at 280°C under nitrogen for 1 hour. The reaction mixture was cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, twice to obtain a pink precipitate, i.e., the core layer LiErF4:0.5% Tm nanoparticles, which were stored in cyclohexane.
[0135] (2) LiYF4: 50% Yb, 2% Er shell coating: 10 mL of oleic acid and 15 mL of octadecene were stirred thoroughly in a three-necked flask and mixed evenly. Then, 1.2 mL of 0.04 mol·L -1 Yttrium-oleic acid chelate, 1.25mL concentration is 0.04mol·L -1 Ytterbium-oleic acid chelate and 0.05mL of 0.04mol·L -1The erbium-oleic acid chelate was mixed and stirred evenly, and the core layer LiErF4:0.5% Tm nanoparticles prepared in step (1) were added, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 The methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. The reaction was then carried out at 280°C for 1 hour under nitrogen protection and then naturally cooled to obtain a reaction solution of LiErF4:0.5%Tm@LiYF4:50%Yb,2%Er core-shell nanoparticles.
[0136] (3) LiYF4 passivation layer coating: take 2.5mL of 0.04mol·L -1 The yttrium-oleic acid chelate was added to the reaction solution after natural cooling in step (3), stirred evenly, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes, after which excess methanol was removed. The mixture was then reacted at 280°C for 1 hour under nitrogen protection. The resulting mixture was cooled naturally to room temperature, washed with anhydrous ethanol, and centrifuged twice at 10,000 rpm for 10 minutes to obtain a precipitate, namely, LiErF4:0.5% Tm@LiYF4:50% Yb, 2% Er@LiYF4 core-shell-shell nanoparticles. The precipitate was then stored in cyclohexane, yielding the red-emitting upconversion nanomaterial of this embodiment.
[0137] Example 3
[0138] This embodiment provides a method for preparing a red-light-emitting upconversion nanomaterial LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er@LiYF4, including the following steps:
[0139] (1) LiErF4:0.5% Tm core layer preparation: 15 mL of oleic acid and 20 mL of octadecene were added to a three-necked flask and stirred thoroughly to mix well. Then, 1.99 mL of 0.5 mol·L -1 of erbium chloride solution and 0.05 mL of 0.1 mol·L -1 The thulium chloride solution was stirred thoroughly and mixed evenly, then heated to 105°C to remove water from the solution, and then subjected to high temperature reaction at 150°C for 1.5 hours to generate rare earth-oleic acid chelate;
[0140] Then naturally cooled to room temperature, 5 mL of 0.5 mol·L -1Lithium hydroxide methanol solution and 5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was added to the rare earth-oleic acid chelate prepared above and stirred uniformly. The temperature was raised to 90°C for 1 hour, and excess methanol was removed. The reaction was then carried out at 280°C under nitrogen for 1 hour. The reaction mixture was cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, twice to obtain a pink precipitate, namely, LiErF4:0.5% Tm core layer nanoparticles, which were stored in cyclohexane.
[0141] (2) LiYF4: 50% Yb, 5% Er shell coating: 10 mL of oleic acid and 15 mL of octadecene were stirred thoroughly in a three-necked flask and mixed evenly. Then, 1.125 mL of 0.04 mol·L -1 Yttrium-oleic acid chelate, 1.25mL concentration is 0.04mol·L -1 Ytterbium-oleic acid chelate and 0.125mL of 0.04mol·L -1 The erbium-oleic acid chelate was mixed and stirred evenly, and the core layer LiErF4:0.5% Tm nanoparticles prepared in step (1) were added, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. The mixture was then reacted at 280°C for 1 hour under nitrogen protection and then naturally cooled to obtain a reaction solution of LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er core-shell structured nanoparticles.
[0142] (3) LiYF4 passivation layer coating: take 2.5mL of 0.04mol·L -1 The yttrium-oleic acid chelate was added to the reaction solution after natural cooling in step (3), stirred evenly, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes, after which excess methanol was removed. The mixture was then reacted at 280°C for 1 hour under nitrogen protection. The resulting mixture was naturally cooled to room temperature, washed with anhydrous ethanol, and centrifuged twice at 10,000 rpm for 10 minutes to obtain a precipitate, namely, LiErF4:0.5% Tm@LiYF4:50% Yb, 5% Er@LiYF4 core-shell-shell nanoparticles. The precipitate was then stored in cyclohexane, yielding the red-emitting upconversion nanomaterial of this embodiment.
[0143] Example 4
[0144] This embodiment provides a method for preparing a red-light-emitting upconversion nanomaterial LiErF4:0.5%Tm@LiYF4:50%Yb,8%Er@LiYF4, including the following steps:
[0145] (1) LiErF4:0.5% Tm core layer preparation: 15 mL of oleic acid and 20 mL of octadecene were added to a three-necked flask and stirred thoroughly to mix well. Then, 1.99 mL of 0.5 mol·L -1 of erbium chloride solution and 0.05 mL of 0.1 mol·L -1 The thulium chloride solution was stirred thoroughly and mixed evenly, then heated to 105°C to remove water from the solution, and then subjected to high temperature reaction at 150°C for 1.5 hours to generate rare earth-oleic acid chelate;
[0146] Then naturally cooled to room temperature, 5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was added to the rare earth-oleic acid chelate prepared above and stirred uniformly. The temperature was raised to 90°C for 1 hour, and excess methanol was removed. The reaction was then carried out at 280°C under nitrogen for 1 hour. The reaction mixture was cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, twice to obtain a pink precipitate, namely, LiErF4:0.5% Tm core layer nanoparticles, which were stored in cyclohexane.
[0147] (2) LiYF4: 50% Yb, 8% Er shell coating: 10 mL of oleic acid and 15 mL of octadecene were stirred thoroughly in a three-necked flask and mixed evenly. Then, 1.05 mL of 0.04 mol·L -1 Yttrium-oleic acid chelate, 1.25mL concentration is 0.04mol·L -1 Ytterbium-oleic acid chelate and 0.2mL of 0.04mol·L -1 The erbium-oleic acid chelate was mixed and stirred evenly, and the core layer LiErF4:0.5% Tm nanoparticles prepared in step (1) were added, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1A methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. The mixture was then reacted at 280°C for 1 hour under nitrogen protection and then naturally cooled to obtain a reaction solution of LiErF4:0.5%Tm@LiYF4:50%Yb,8%Er core-shell structured nanoparticles.
[0148] (3) LiYF4 passivation layer coating: take 2.5mL of 0.04mol·L -1 The yttrium-oleic acid chelate was added to the reaction solution after natural cooling in step (3), stirred evenly, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was stirred, heated to 90°C, maintained for 45 minutes, and excess methanol was removed. Then, under nitrogen protection, the mixture was reacted at 280°C for 1 hour. Finally, the reaction mixture was naturally cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, for a total of 2 centrifugations to obtain a precipitate, namely LiErF4:0.5%Tm@LiYF4:50%Yb,8%Er@LiYF4 core-shell-shell structured nanoparticles, which were stored in cyclohexane; and the upconversion nanomaterial with red light emission of this embodiment was obtained.
[0149] Example 5
[0150] This embodiment provides a method for preparing a red-light-emitting upconversion nanomaterial LiErF4:0.5%Tm@LiYF4:50%Yb,10%Er@LiYF4, comprising the following steps:
[0151] (1) LiErF4:0.5% Tm core layer preparation: 15 mL of oleic acid and 20 mL of octadecene were added to a three-necked flask and stirred thoroughly to mix well. Then, 1.99 mL of 0.5 mol·L -1 of erbium chloride solution and 0.05 mL of 0.1 mol·L -1 The thulium chloride solution was stirred thoroughly and mixed evenly, then heated to 105°C to remove water from the solution, and then subjected to high temperature reaction at 150°C for 1.5 hours to generate rare earth-oleic acid chelate;
[0152] Then naturally cooled to room temperature, 5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 5mL of 0.8mol·L -1A methanol solution of ammonium fluoride was added to the rare earth-oleic acid chelate prepared above and stirred uniformly. The temperature was raised to 90°C for 1 hour, and excess methanol was removed. The reaction was then carried out at 280°C under nitrogen for 1 hour. The reaction mixture was cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, twice to obtain a pink precipitate, namely, LiErF4:0.5% Tm core layer nanoparticles, which were stored in cyclohexane.
[0153] (2) LiYF4: 50% Yb, 10% Er shell coating: 10 mL of oleic acid and 15 mL of octadecene were stirred thoroughly in a three-necked flask and mixed evenly. Then, 1 mL of 0.04 mol·L -1 Yttrium-oleic acid chelate, 1.25mL concentration is 0.04mol·L -1 Ytterbium-oleic acid chelate and 0.25mL of 0.04mol·L -1 The erbium-oleic acid chelate was mixed and stirred evenly, and the core layer LiErF4:0.5% Tm nanoparticles prepared in step (1) were added, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 The methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. Then, the mixture was reacted at 280°C for 1 hour under nitrogen protection and cooled naturally to obtain a reaction solution of LiErF4:0.5%Tm@LiYF4:50%Yb,10%Er core-shell structured nanoparticles.
[0154] (3) LiYF4 passivation layer coating: take 2.5mL of 0.04mol·L -1 The yttrium-oleic acid chelate was added to the reaction solution after natural cooling in step (3), stirred evenly, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. The mixture was then reacted at 280°C for 1 hour under nitrogen protection. The reaction mixture was naturally cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, for a total of two centrifugations, to obtain a precipitate, namely LiErF4:0.5% Tm@LiYF4:50% Yb, 10% Er@LiYF4 core-shell-shell structured nanoparticles, which were stored in cyclohexane to obtain the upconversion nanomaterial with red light emission of this embodiment.
[0155] Example 6
[0156] This embodiment provides a method for preparing a red-light-emitting upconversion nanomaterial LiErF4:0.5%Tm@LiYF4:50%Yb,15%Er@LiYF4, comprising the following steps:
[0157] (1) LiErF4:0.5% Tm core layer preparation: 15 mL of oleic acid and 20 mL of octadecene were added to a three-necked flask and stirred thoroughly to mix well. Then, 1.99 mL of 0.5 mol·L -1 of erbium chloride solution and 0.05 mL of 0.1 mol·L -1 The thulium chloride solution was stirred thoroughly and mixed evenly, then heated to 105°C to remove water from the solution, and then subjected to high temperature reaction at 150°C for 1.5 hours to generate rare earth-oleic acid chelate;
[0158] Then naturally cooled to room temperature, 5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was added to the rare earth-oleic acid chelate prepared above and stirred uniformly. The temperature was raised to 90°C for 1 hour, and excess methanol was removed. The reaction was then carried out at 280°C under nitrogen for 1 hour. The reaction mixture was cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, twice to obtain a pink precipitate, namely, LiErF4:0.5% Tm core layer nanoparticles, which were stored in cyclohexane.
[0159] (2) LiYF4: 50% Yb, 15% Er shell coating: 10 mL of oleic acid and 15 mL of octadecene were stirred thoroughly in a three-necked flask and mixed evenly. Then, 0.875 mL of 0.04 mol·L -1 Yttrium-oleic acid chelate, 1.25mL concentration is 0.04mol·L -1 Ytterbium-oleic acid chelate and 0.375mL of 0.04mol·L -1 The erbium-oleic acid chelate was mixed and stirred evenly, and the core layer LiErF4:0.5% Tm nanoparticles prepared in step (1) were added, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 The methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. Then, the reaction was carried out at 280°C for 1 hour under nitrogen protection and finally cooled naturally to obtain a reaction solution of LiErF4:0.5%Tm@LiYF4:50%Yb,15%Er core-shell structured nanoparticles.
[0160] (3) LiYF4 passivation layer coating: take 2.5mL of 0.04mol·L -1 The yttrium-oleic acid chelate was added to the reaction solution after natural cooling in step (3), stirred evenly, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was stirred and heated to 90°C and maintained for 45 minutes to remove excess methanol. The mixture was then reacted at 280°C for 1 hour under nitrogen protection. The reaction mixture was naturally cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, for a total of 2 centrifugations, to obtain a precipitate, namely LiErF4:0.5% Tm@LiYF4:50% Yb, 15% Er@LiYF4 core-shell-shell structured nanoparticles, which were stored in cyclohexane to obtain the upconversion nanomaterial with red light emission of this embodiment.
[0161] Example 7
[0162] This embodiment provides a method for preparing a red-light-emitting upconversion nanomaterial LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,0.2%Ce@LiYF4, comprising the following steps:
[0163] (1) LiErF4:0.5% Tm core layer preparation: 15 mL of oleic acid and 20 mL of octadecene were added to a three-necked flask and stirred thoroughly to mix well. Then, 1.99 mL of 0.5 mol·L -1 of erbium chloride solution and 0.05 mL of 0.1 mol·L -1 The thulium chloride solution was stirred thoroughly and mixed evenly, then heated to 105°C to remove water from the solution, and then subjected to high temperature reaction at 150°C for 1.5 hours to generate rare earth-oleic acid chelate;
[0164] Then naturally cooled to room temperature, 5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was added to the rare earth-oleic acid chelate prepared above and stirred uniformly. The temperature was raised to 90°C for 1 hour, and excess methanol was removed. The reaction was then carried out at 280°C under nitrogen for 1 hour. The reaction mixture was cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, twice to obtain a pink precipitate, namely, LiErF4:0.5% Tm core layer nanoparticles, which were stored in cyclohexane.
[0165] (2) LiYF4: 50% Yb, 5% Er, 0.2% Ce shell coating: 10 mL of oleic acid and 15 mL of octadecene were stirred thoroughly in a three-necked flask and mixed evenly. Then, 1.12 mL of 0.04 mol·L -1 Yttrium-oleic acid chelate, 1.25mL concentration is 0.04mol·L -1 Ytterbium-oleic acid chelate, 0.125mL concentration is 0.04mol·L -1 Erbium-oleic acid chelate and 0.05mL of 0.004mol·L -1 The cerium-oleic acid chelate was mixed and stirred evenly, and the core layer LiErF4:0.5% Tm nanoparticles prepared in step (1) were added, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 The methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. Then, the reaction was carried out at 280°C for 1 hour under nitrogen protection and finally cooled naturally to obtain a reaction solution of LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,0.2%Ce core-shell structured nanoparticles;
[0166] (3) LiYF4 passivation layer coating: take 2.5mL of 0.04mol·L -1 The yttrium-oleic acid chelate was added to the reaction solution after natural cooling in step (3), stirred evenly, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was stirred, heated to 90°C, maintained for 45 minutes, and excess methanol was removed. Then, under nitrogen protection, the mixture was reacted at 280°C for 1 hour. Finally, the reaction mixture was naturally cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, for a total of 2 centrifugations to obtain a precipitate, namely LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,0.2%Ce@LiYF4 core-shell-shell structured nanoparticles, which were stored in cyclohexane; the upconversion nanomaterial with red light emission of this embodiment was obtained.
[0167] Example 8
[0168] This embodiment provides a method for preparing a red-light-emitting upconversion nanomaterial LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,0.5%Ce@LiYF4, comprising the following steps:
[0169] (1) LiErF4:0.5% Tm core layer preparation: 15 mL of oleic acid and 20 mL of octadecene were added to a three-necked flask and stirred thoroughly to mix well. Then, 1.99 mL of 0.5 mol·L -1 of erbium chloride solution and 0.05 mL of 0.1 mol·L -1 The thulium chloride solution was stirred thoroughly and mixed evenly, then heated to 105°C to remove water from the solution, and then subjected to high temperature reaction at 150°C for 1.5 hours to generate rare earth-oleic acid chelate;
[0170] Then naturally cooled to room temperature, 5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was added to the rare earth-oleic acid chelate prepared above and stirred uniformly. The temperature was raised to 90°C for 1 hour, and excess methanol was removed. The reaction was then carried out at 280°C under nitrogen for 1 hour. The reaction mixture was cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, twice to obtain a pink precipitate, namely, LiErF4:0.5% Tm core layer nanoparticles, which were stored in cyclohexane.
[0171] (2) LiYF4: 50% Yb, 5% Er, 0.5% Ce shell coating: 10 mL of oleic acid and 15 mL of octadecene were stirred thoroughly in a three-necked flask and mixed evenly. Then, 1.1125 mL of 0.04 mol·L -1 Yttrium-oleic acid chelate, 1.25mL concentration is 0.04mol·L -1 Ytterbium-oleic acid chelate, 0.125mL concentration is 0.04mol·L -1 Erbium-oleic acid chelate and 0.125mL of 0.004mol·L -1 The cerium-oleic acid chelate was mixed and stirred evenly, and the core layer LiErF4:0.5% Tm nanoparticles prepared in step (1) were added, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 The methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. Then, the reaction was carried out at 280°C for 1 hour under nitrogen protection and finally cooled naturally to obtain a reaction solution of LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,0.5%Ce core-shell structured nanoparticles;
[0172] (3) LiYF4 passivation layer coating: take 2.5mL of 0.04mol·L -1The yttrium-oleic acid chelate was added to the reaction solution after natural cooling in step (3), stirred evenly, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was stirred, heated to 90°C, maintained for 45 minutes, and excess methanol was removed. Then, under nitrogen protection, the mixture was reacted at 280°C for 1 hour. Finally, the reaction mixture was naturally cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, for a total of 2 centrifugations to obtain a precipitate, namely LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,0.5%Ce@LiYF4 core-shell-shell structured nanoparticles, which were stored in cyclohexane; the upconversion nanomaterial with red light emission of this embodiment was obtained.
[0173] Example 9
[0174] This embodiment provides a method for preparing a red-light-emitting upconversion nanomaterial LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,1%Ce@LiYF4, including the following steps:
[0175] (1) LiErF4:0.5% Tm core layer preparation: 15 mL of oleic acid and 20 mL of octadecene were added to a three-necked flask and stirred thoroughly to mix well. Then, 1.99 mL of 0.5 mol·L -1 of erbium chloride solution and 0.05 mL of 0.1 mol·L -1 The thulium chloride solution was stirred thoroughly and mixed evenly, then heated to 105°C to remove water from the solution, and then subjected to high temperature reaction at 150°C for 1.5 hours to generate rare earth-oleic acid chelate;
[0176] Then naturally cooled to room temperature, 5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was added to the rare earth-oleic acid chelate prepared above and stirred uniformly. The temperature was raised to 90°C for 1 hour, and excess methanol was removed. The reaction was then carried out at 280°C under nitrogen for 1 hour. The reaction mixture was cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, twice to obtain a pink precipitate, namely, LiErF4:0.5% Tm core layer nanoparticles, which were stored in cyclohexane.
[0177] (2) LiYF4: 50% Yb, 5% Er, 1% Ce shell coating: 10 mL of oleic acid and 15 mL of octadecene were stirred thoroughly in a three-necked flask and mixed evenly. Then, 1.1 mL of 0.04 mol·L -1 Yttrium-oleic acid chelate, 1.25mL concentration is 0.04mol·L -1 Ytterbium-oleic acid chelate, 0.125mL concentration is 0.04mol·L -1 Erbium-oleic acid chelate and 0.25mL of 0.004mol·L -1 The cerium-oleic acid chelate was mixed and stirred evenly, and the core layer LiErF4:0.5% Tm nanoparticles prepared in step (1) were added, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 The methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. Then, the reaction was carried out at 280°C for 1 hour under nitrogen protection and finally cooled naturally to obtain a reaction solution of LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,1%Ce core-shell structured nanoparticles;
[0178] (3) LiYF4 passivation layer coating: take 2.5mL of 0.04mol·L -1 The yttrium-oleic acid chelate was added to the reaction solution after natural cooling in step (3), stirred evenly, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was stirred, heated to 90°C, maintained for 45 minutes, and excess methanol was removed. Then, under nitrogen protection, the mixture was reacted at 280°C for 1 hour. Finally, the reaction mixture was naturally cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, for a total of 2 centrifugations to obtain a precipitate, namely LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,1%Ce@LiYF4 core-shell-shell structured nanoparticles, which were stored in cyclohexane; the upconversion nanomaterial with red light emission of this embodiment was obtained.
[0179] Example 10
[0180] This embodiment provides a method for preparing a red-light-emitting upconversion nanomaterial LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,1.5%Ce@LiYF4, comprising the following steps:
[0181] (1) LiErF4:0.5% Tm core layer preparation: 15 mL of oleic acid and 20 mL of octadecene were added to a three-necked flask and stirred thoroughly to mix well. Then, 1.99 mL of 0.5 mol·L -1 of erbium chloride solution and 0.05 mL of 0.1 mol·L -1 The thulium chloride solution was stirred thoroughly and mixed evenly, then heated to 105°C to remove water from the solution, and then subjected to high temperature reaction at 150°C for 1.5 hours to generate rare earth-oleic acid chelate;
[0182] Then naturally cooled to room temperature, 5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was added to the rare earth-oleic acid chelate prepared above and stirred uniformly. The temperature was raised to 90°C for 1 hour, and excess methanol was removed. The reaction was then carried out at 280°C under nitrogen for 1 hour. The reaction mixture was cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, twice to obtain a pink precipitate, namely, LiErF4:0.5% Tm core layer nanoparticles, which were stored in cyclohexane.
[0183] (2) LiYF4: 50% Yb, 5% Er, 1.5% Ce shell coating: 10 mL of oleic acid and 15 mL of octadecene were stirred thoroughly in a three-necked flask and mixed evenly. Then, 1.0875 mL of 0.04 mol·L -1 Yttrium-oleic acid chelate, 1.25mL concentration is 0.04mol·L -1 Ytterbium-oleic acid chelate, 0.125mL concentration is 0.04mol·L -1 Erbium-oleic acid chelate and 0.375 mL of 0.004 mol·L -1 Add the core layer LiErF4:0.5% Tm nanoparticles prepared in step (1), and then add 0.5mL of 0.5mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 The methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. Then, the reaction was carried out at 280°C for 1 hour under nitrogen protection and finally cooled naturally to obtain a reaction solution of LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,1.5%Ce core-shell structured nanoparticles;
[0184] (3) LiYF4 passivation layer coating: take 2.5mL of 0.04mol·L -1The yttrium-oleic acid chelate was added to the reaction solution after natural cooling in step (3), stirred evenly, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was stirred, heated to 90°C, maintained for 45 minutes, and excess methanol was removed. Then, under nitrogen protection, the mixture was reacted at 280°C for 1 hour. Finally, the reaction mixture was naturally cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, for a total of 2 centrifugations to obtain a precipitate, namely LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,1.5%Ce@LiYF4 core-shell-shell structured nanoparticles, which were stored in cyclohexane; the upconversion nanomaterial with red light emission of this embodiment was obtained.
[0185] Example 11
[0186] This embodiment provides a method for preparing a red-light-emitting upconversion nanomaterial LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,2%Ce@LiYF4, including the following steps:
[0187] (1) LiErF4:0.5% Tm core layer preparation: 15 mL of oleic acid and 20 mL of octadecene were added to a three-necked flask and stirred thoroughly to mix well. Then, 1.99 mL of 0.5 mol·L -1 of erbium chloride solution and 0.05 mL of 0.1 mol·L -1 The thulium chloride solution was stirred thoroughly and mixed evenly, then heated to 105°C to remove water from the solution, and then subjected to high temperature reaction at 150°C for 1.5 hours to generate rare earth-oleic acid chelate;
[0188] Then naturally cooled to room temperature, 5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was added to the rare earth-oleic acid chelate prepared above and stirred uniformly. The temperature was raised to 90°C for 1 hour, and excess methanol was removed. The reaction was then carried out at 280°C under nitrogen for 1 hour. The reaction mixture was cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, twice to obtain a pink precipitate, namely, LiErF4:0.5% Tm core layer nanoparticles, which were stored in cyclohexane.
[0189] (2) LiYF4: 50% Yb, 5% Er, 2% Ce shell coating: 10 mL of oleic acid and 15 mL of octadecene were stirred thoroughly in a three-necked flask and mixed evenly. Then, 1.075 mL of 0.04 mol·L -1 Yttrium-oleic acid chelate, 1.25mL concentration is 0.04mol·L -1 Ytterbium-oleic acid chelate, 0.125mL concentration is 0.04mol·L -1 Erbium-oleic acid chelate and 0.5mL of 0.004mol·L -1 The cerium-oleic acid chelate was mixed and stirred evenly, and the core layer LiErF4:0.5% Tm nanoparticles prepared in step (1) were added, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 The methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. Then, the reaction was carried out at 280°C for 1 hour under nitrogen protection and finally cooled naturally to obtain a reaction solution of LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,2%Ce core-shell structured nanoparticles;
[0190] (3) LiYF4 passivation layer coating: take 2.5mL of 0.04mol·L -1 The yttrium-oleic acid chelate was added to the reaction solution after natural cooling in step (3), stirred evenly, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was stirred, heated to 90°C, maintained for 45 minutes, and excess methanol was removed. Then, under nitrogen protection, the mixture was reacted at 280°C for 1 hour. Finally, the reaction mixture was naturally cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, for a total of 2 centrifugations to obtain a precipitate, namely LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,2%Ce@LiYF4 core-shell-shell structure nanoparticles, which were stored in cyclohexane; the upconversion nanomaterial with red light emission of this embodiment was obtained.
[0191] Example 12
[0192] This embodiment provides a method for preparing a red-light-emitting upconversion nanomaterial LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,3%Ce@LiYF4, including the following steps:
[0193] (1) LiErF4:0.5% Tm core layer preparation: 15 mL of oleic acid and 20 mL of octadecene were added to a three-necked flask and stirred thoroughly to mix well. Then, 1.99 mL of 0.5 mol·L -1 of erbium chloride solution and 0.05 mL of 0.1 mol·L -1 The thulium chloride solution was stirred thoroughly and mixed evenly, then heated to 105°C to remove water from the solution, and then subjected to high temperature reaction at 150°C for 1.5 hours to generate rare earth-oleic acid chelate;
[0194] Then naturally cooled to room temperature, 5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was added to the rare earth-oleic acid chelate prepared above and stirred uniformly. The temperature was raised to 90°C for 1 hour, and excess methanol was removed. The reaction was then carried out at 280°C under nitrogen for 1 hour. The reaction mixture was cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, twice to obtain a pink precipitate, namely, LiErF4:0.5% Tm core layer nanoparticles, which were stored in cyclohexane.
[0195] (2) LiYF4: 50% Yb, 5% Er, 3% Ce shell coating: 10 mL of oleic acid and 15 mL of octadecene were stirred thoroughly in a three-necked flask and mixed evenly. Then, 1.05 mL of 0.04 mol·L -1 Yttrium-oleic acid chelate, 1.25mL concentration is 0.04mol·L -1 Ytterbium-oleic acid chelate, 0.125mL concentration is 0.04mol·L -1 Erbium-oleic acid chelate and 0.75 mL of 0.004 mol·L -1 The cerium-oleic acid chelate was mixed and stirred evenly, and the core layer LiErF4:0.5% Tm nanoparticles prepared in step (1) were added, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 The methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. Then, the reaction was carried out at 280°C for 1 hour under nitrogen protection and finally cooled naturally to obtain a reaction solution of LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,3%Ce core-shell structured nanoparticles;
[0196] (3) LiYF4 passivation layer coating: take 2.5mL of 0.04mol·L -1The yttrium-oleic acid chelate was added to the reaction solution after natural cooling in step (3), stirred evenly, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was stirred, heated to 90°C, maintained for 45 minutes, and excess methanol was removed. Then, under nitrogen protection, the mixture was reacted at 280°C for 1 hour. Finally, the reaction mixture was naturally cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, for a total of 2 centrifugations to obtain a precipitate, namely LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,3%Ce@LiYF4 core-shell-shell structured nanoparticles, which were stored in cyclohexane; the upconversion nanomaterial with red light emission of this embodiment was obtained.
[0197] Example 13
[0198] This embodiment provides a method for preparing a red-light-emitting upconversion nanomaterial LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,4%Ce@LiYF4, comprising the following steps:
[0199] (1) LiErF4:0.5% Tm core layer preparation: 15 mL of oleic acid and 20 mL of octadecene were added to a three-necked flask and stirred thoroughly to mix well. Then, 1.99 mL of 0.5 mol·L -1 of erbium chloride solution and 0.05 mL of 0.1 mol·L -1 The thulium chloride solution was stirred thoroughly and mixed evenly, then heated to 105°C to remove water from the solution, and then subjected to high temperature reaction at 150°C for 1.5 hours to generate rare earth-oleic acid chelate;
[0200] Then naturally cooled to room temperature, 5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was added to the rare earth-oleic acid chelate prepared above and stirred uniformly. The temperature was raised to 90°C for 1 hour, and excess methanol was removed. The reaction was then carried out at 280°C under nitrogen for 1 hour. The reaction mixture was cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, twice to obtain a pink precipitate, namely, LiErF4:0.5% Tm core layer nanoparticles, which were stored in cyclohexane.
[0201] (2) LiYF4: 50% Yb, 5% Er, 4% Ce shell coating: 10 mL of oleic acid and 15 mL of octadecene were stirred thoroughly in a three-necked flask and mixed evenly. Then, 1.025 mL of 0.04 mol·L -1 Yttrium-oleic acid chelate, 1.25mL concentration is 0.04mol·L -1 Ytterbium-oleic acid chelate, 0.125mL concentration is 0.04mol·L -1 Erbium-oleic acid chelate and 1mL concentration of 0.004mol·L -1 The cerium-oleic acid chelate was mixed and stirred evenly, and the core layer LiErF4:0.5% Tm nanoparticles prepared in step (1) were added, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 The methanol solution of ammonium fluoride was stirred and heated to 90°C for 45 minutes to remove excess methanol. Then, the reaction was carried out at 280°C for 1 hour under nitrogen protection and finally cooled naturally to obtain a reaction solution of LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,4%Ce core-shell structured nanoparticles;
[0202] (3) LiYF4 passivation layer coating: take 2.5mL of 0.04mol·L -1 The yttrium-oleic acid chelate was added to the reaction solution after natural cooling in step (3), stirred evenly, and then 0.5 mL of 0.5 mol·L -1 Lithium hydroxide methanol solution and 0.5mL of 0.8mol·L -1 A methanol solution of ammonium fluoride was stirred, heated to 90°C, maintained for 45 minutes, and excess methanol was removed. Then, under nitrogen protection, the mixture was reacted at 280°C for 1 hour. Finally, the reaction mixture was naturally cooled to room temperature, washed with anhydrous ethanol, and centrifuged at 10,000 rpm for 10 minutes, for a total of 2 centrifugations to obtain a precipitate, namely LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,4%Ce@LiYF4 core-shell-shell structured nanoparticles, which were stored in cyclohexane; the upconversion nanomaterial with red light emission of this embodiment was obtained.
[0203] Test Case
[0204] The morphology of the LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,1%Ce@LiYF4 upconversion nanomaterial prepared in Example 9 was analyzed by transmission electron microscopy. Figure 1As shown, it is proved that the obtained nanomaterial morphology is highly uniform and dispersed, and the average size is 37.36nm; in addition, the nanomaterial has a pure tetragonal phase lattice structure.
[0205] The fluorescence spectra of the LiErF4:0.5%Tm@LiYF4:50%Yb,x%Er,y%Ce@LiYF4 upconversion nanomaterials prepared in Example 1-13 were analyzed under 980nm excitation using a fluorescence spectrometer. Figure 2 and Figure 3 As shown in the figure, by comparing the two figures, it can be seen that by doping with an appropriate concentration of Er 3+ With Ce 3+ , the red light emission of the nanomaterial is effectively enhanced.
[0206] Figure 4 This is the upconversion energy level transition diagram of the LiErF4:0.5%Tm@LiYF4:50%Yb,5%Er,1%Ce@LiYF4 upconversion nanomaterial prepared in Example 9 under 980nm excitation. Figure 4 It can be seen that by using LiErF4:0.5%Tm as the core layer and coating it with LiYF4:Yb, Er, Ce shell layer and LiYF4 passivation layer, 3+ As an energy harvester, and using Er 3+ With Ce 3+ The cross-relaxation effect between Er 3+ Yb 3+ The maximum absorption of spontaneous radiation energy results in obvious red light emission.
[0207] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.
Claims
1. An upconversion nanomaterial with red light emission, characterized in that: The upconversion nanomaterial with red light emission has LiErF4:0.5%Tm as a core layer, and a LiYF4:50%Yb,x%Er,y%Ce shell layer and a LiYF4 passivation layer are sequentially coated on the outside of the core layer; the chemical formula of the upconversion nanomaterial with red light emission is LiErF4:0.5%Tm@LiYF4:50%Yb,x%Er,y%Ce@LiYF4; wherein 0<x≤15, 0<y≤4.
2. A method for preparing the upconversion nanomaterial with red light emission according to claim 1, characterized in that: The following steps are involved: (1) Oleic acid, octadecene, erbium salt solution and thulium salt solution are mixed uniformly, heated to remove water, heated to react to form rare earth-oleic acid chelate, cooled to remove methanol solution of lithium hydroxide and methanol solution of ammonium fluoride, stirred, heated to remove methanol, and then reacted at high temperature under an inert atmosphere to obtain core layer LiErF4:0.5%Tm nanoparticles; (2) After oleic acid, octadecene, yttrium-oleic acid chelate, ytterbium-oleic acid chelate, erbium-oleic acid chelate and cerium-oleic acid chelate are uniformly mixed, the core layer LiErF4:0.5%Tm nanoparticles obtained in step (1) are added, and then a methanol solution of lithium hydroxide and a methanol solution of ammonium fluoride are added and stirred, the temperature is increased to remove the methanol, and then the reaction is carried out at high temperature under an inert atmosphere to obtain a LiErF4:0.5%Tm@LiYF4:50%Yb,x%Er,y%Ce core-shell structure nanoparticle solution; (3) adding yttrium-oleic acid chelate to the solution obtained in step (2), mixing uniformly, then adding a methanol solution of lithium hydroxide and a methanol solution of ammonium fluoride and stirring, heating to remove methanol, and then reacting at high temperature under an inert atmosphere to obtain the upconversion nanomaterial having red light emission; In the steps (1), (2) and (3), the temperature of the high-temperature reaction is 280° C.-290° C.
3. The method for preparing an upconversion nanomaterial having red light emission according to claim 2, characterized in that: In the step (1), the volume ratio of the oleic acid to octadecene is (0.65-0.85):1; the volume ratio of the oleic acid to the bait salt solution is 300:(38.8-40.8); the volume ratio of the oleic acid to the thulium salt solution is 300:(0.5-1.5); the volume ratio of the lithium hydroxide methanol solution to the ammonium fluoride methanol solution is (0.8-1.2):1; and the volume ratio of the bait salt solution to the lithium hydroxide methanol solution is (37.8-41.8):
100.
4. The method for preparing an upconversion nanomaterial having red light emission according to claim 2, characterized in that: In step (1), the concentration of the bait salt solution is 0.4 mol·L -1 -0.6 mol·L -1 The concentration of the thulium salt solution is 0.08 mol·L -1 -0.12 mol·L -1 The heating reaction temperature is 145°C-155°C and the time is 1h-1.5h.
5. The method for preparing an upconversion nanomaterial having red light emission according to claim 2, characterized in that: In the step (1), the bait salt includes bait chloride, and the thulium salt includes thulium chloride; and the temperature for heating to remove moisture in the step (1) is 90° C.-110° C.
6. The method for preparing an upconversion nanomaterial having red light emission according to claim 2, characterized in that: In the step (2), the volume ratio of oleic acid to octadecene is (1.8-2.2):3; the volume ratio of oleic acid to yttrium-oleic acid chelate is 100:(10.25-11.25); the volume ratio of oleic acid to ytterbium-oleic acid chelate is 10:(1-1.5); the volume ratio of oleic acid to erbium-oleic acid chelate is 100:(0-3.75); the volume ratio of oleic acid to cerium-oleic acid chelate is 100:(0-3.75); The volume ratio of the material is 10:(0-1); the molar ratio of the core layer LiErF4:0.5%Tm nanoparticles to the yttrium-oleic acid chelate is 1:(0.41-0.45); the volume ratio of the yttrium-oleic acid chelate and the methanol solution of lithium hydroxide is (2.05-2.25):1; the volume ratio of the yttrium-oleic acid chelate and the methanol solution of ammonium fluoride is (2.05-2.25):
1.
7. The method for preparing an upconversion nanomaterial having red light emission according to claim 2, characterized in that: In step (2), the concentration of the yttrium-oleic acid chelate is 0.035 mol·L -1 -0.045 mol·L -1 The concentration of the ytterbium-oleic acid chelate is 0.035 mol·L -1 -0.045 mol·L -1 The concentration of the erbium-oleic acid chelate is 0.035 mol·L -1 -0.045 mol·L -1 The concentration of the cerium-oleic acid chelate is 0.002 mol·L -1 -0.006 mol·L -1 .
8. The method for preparing an upconversion nanomaterial having red light emission according to claim 2, characterized in that: In step (3), the concentration of the yttrium-oleic acid chelate is 0.035 mol·L -1 -0.045 mol·L -1 ; The molar ratio of the yttrium-oleic acid chelate to the core layer LiErF4: 0.5%Tm nanoparticles in step (2) is (0.8-1.2):1; the volume ratio of the yttrium-oleic acid chelate to the methanol solution of lithium hydroxide is (4.5-5.5):1; the volume ratio of the yttrium-oleic acid chelate to the methanol solution of ammonium fluoride is (4.5-5.5):
1.
9. The method for preparing an upconversion nanomaterial having red light emission according to claim 2, characterized in that: In the steps (1), (2) and (3), the high temperature reaction time is 0.9 h to 1.1 h.
10. The method for preparing an upconversion nanomaterial with red light emission according to claim 2, characterized in that: In the steps (1), (2) and (3), the temperature for removing methanol by heating is 80° C. to 100° C.; the inert atmosphere comprises nitrogen; the concentration of lithium hydroxide in the methanol solution is 0.2 mol / L to 0.8 mol / L; the concentration of ammonium fluoride in the methanol solution is 0.5 mol / L to 1 mol / L; And / or, in the step (1) and the step (3), washing and centrifugation are further performed after the high temperature reaction.