CN108531180B - Fluorescence adjustable core-shell nanocrystal and preparation method thereof - Google Patents
Fluorescence adjustable core-shell nanocrystal and preparation method thereof Download PDFInfo
- Publication number
- CN108531180B CN108531180B CN201810479184.2A CN201810479184A CN108531180B CN 108531180 B CN108531180 B CN 108531180B CN 201810479184 A CN201810479184 A CN 201810479184A CN 108531180 B CN108531180 B CN 108531180B
- Authority
- CN
- China
- Prior art keywords
- core
- nanocrystal
- light
- microemulsion
- fluorescence
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
- C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
- C09K11/77—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals
- C09K11/7766—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing rare earth metals containing two or more rare earth metals
- C09K11/7767—Chalcogenides
- C09K11/7769—Oxides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y20/00—Nanooptics, e.g. quantum optics or photonic crystals
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y40/00—Manufacture or treatment of nanostructures
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
- C09K11/02—Use of particular materials as binders, particle coatings or suspension media therefor
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Nanotechnology (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- Organic Chemistry (AREA)
- Composite Materials (AREA)
- Optics & Photonics (AREA)
- Biophysics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Inorganic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Luminescent Compositions (AREA)
- Cosmetics (AREA)
Abstract
The invention discloses a core-shell nanocrystal capable of regulating and controlling fluorescence color by changing the wavelength of excitation light or ambient temperature, wherein the nanocrystal consists of Pr3+:Ln2Ti2O7＠Ln2Ti2O7(Ln = La, Gd, Lu) having a crystal nucleus composition of Pr3+:Ln2Ti2O7(Ln = La, Gd, Lu) coated on the outer surface of the crystal nucleus and is homogeneous Ln2Ti2O7(Ln = La, Gd, Lu) outer shell. The fluorescence adjustable core-shell nanocrystal is prepared by adopting an inverse microemulsion-hydrothermal method, and an inverse microemulsion template formed by an emulsifier OP-10, n-butanol, cyclohexane and water can accurately control the morphology and the particle size of the nanocrystal, so that the preparation of the nanocrystal with regular morphology and uniform size distribution is facilitated.
Description
Technical Field
The invention belongs to the field of solid luminescent materials, and particularly relates to a core-shell nanocrystal material capable of regulating and controlling luminescent color through excitation light wavelength or ambient temperature and a preparation method thereof.
Background
The rare earth ion doped luminescent material with multicolor luminescence property has huge application prospect in the fields of biological imaging, illumination display, information storage and the like. At present, the methods for realizing the adjustability of the fluorescence color of the luminescent material mainly comprise the following three methods: 1. doping different kinds of rare earth elements in the same matrix by changing the rare earth elementsThe output of different colors is realized by the soil element types or concentration ratios. E.g. under UV excitation, Eu3+, Tb3+Molybdate, sodium tungstate, aluminate and other doped fluorescent powder can be obtained by changing Eu3+And Tb3+The conversion of the luminescence from red, yellow-green to green is realized. 2. The material with the allotrope is selected as the fluorescent powder substrate, and the luminous color of the fluorescent powder is regulated and controlled by regulating and controlling the crystal structure of the substrate and changing the local lattice environment of the rare earth ions. For example, under the excitation of near ultraviolet light, Ce is changed by doping crystal form regulator3+:Ca2SiO4The crystal structure of (1) can realize that the luminescence is alpha'HThe blue color of the phase turns to green for the alpha phase. 3. Designing a multilayer core-shell nanocrystalline structure, introducing different types of rare earth ions into different shell layers by a layer-by-layer thermal injection method, and realizing the modulation of the emitted light color of the nanocrystalline by adjusting the wavelength and power of excitation light or changing the proportion of the rare earth ions. E.g. by changing the excitation wavelength (980 nm or 797 nm) and power, NaGdF4: Yb, Er＠NaYF4: Yb＠NaGdF4: Yb, Nd＠NaYF4＠NaGdF4: Yb, Tm＠NaYF4The six-layer core-shell nanocrystalline can realize different color output. However, the methods 1 and 2 cannot realize real-time control of fluorescence color in a luminescent material with fixed components and structures, while the method 3 is very tedious and time-consuming in preparation of multilayer rare earth ion doped core-shell nanocrystals and has poor repeatability. These technical defects greatly hinder the application of fluorescence tunable luminescent materials. It follows that it is of great importance to achieve a controllable adjustment of the fluorescence color in a single luminescent material with a fixed composition.
Disclosure of Invention
The invention aims to provide a fluorescent color adjustable core-shell nanocrystal with a single component and a single structure aiming at the defects of the prior art. The core-shell nanocrystal prepared by the method can regulate and control the fluorescence color simply by changing the wavelength of exciting light or the ambient temperature without changing the crystal structure, chemical components or concentration ratio, and has potential application prospects in the fields of illumination display, biological imaging, high-temperature warning and the like.
The fluorescence adjustable core-shell nanocrystal provided by the invention is spherical Pr with the average diameter of 30-60nm3+：Ln2Ti2O7＠Ln2Ti2O7(Ln = La, Gd, Lu) nanocrystals wherein Pr3+The doping concentration is 0.2-4 mol%.
The preparation method of the fluorescence adjustable core-shell nanocrystal comprises the following steps:
(1) adding a certain amount of emulsifier OP-10 (surfactant), n-butanol (cosurfactant) and cyclohexane (oil phase) into a flask, wherein the proportion relationship is 3 ml: 2 ml: (12-16) ml; magnetically stirring at room temperature for 30min to uniformly mix the components to obtain a reverse micelle system for later use;
(2) TiCl with a concentration of 1mol/L4The solution is dropwise added into the reverse micelle system, TiCl4The volume ratio of the solution to the reverse micelle system is 1 ml: (9-10) ml; magnetically stirring in water bath at 50 deg.C for 1-2 hr to obtain TiCl4And (3) micro-emulsion. In the same way, Pr (NO) is prepared separately3)3And Ln (NO)3)3(Ln = La, Gd, Lu) microemulsion;
(3) subjecting the TiCl to4Microemulsion with Ln (NO)3)3(Ln = La, Gd, Lu) microemulsions were mixed in a volume ratio of 1: 1; adding Pr (NO) with a certain molar weight proportion3)3The microemulsion is stirred for 1 hour at room temperature; adjusting the pH value of the microemulsion to 6 by using ammonia water, and stirring for 30min to form a yellow-green microemulsion;
(4) carrying out ultrasonic treatment on the yellow-green microemulsion for 30min, then placing the yellow-green microemulsion into a high-pressure reaction kettle, carrying out hydrothermal treatment at the temperature of 140-170 ℃ for 2-5h, and then cooling to room temperature; washing a product obtained by the hydrothermal reaction with isopropanol and absolute ethyl alcohol, and performing centrifugal separation; drying the obtained precipitate at 60-80 ℃ for 10-15h, and calcining at 550 ℃ for 1h in air atmosphere to obtain the required nanocrystal core;
(5) weighing the Pr3+:Ln2Ti2O7Dispersing the nanocrystal core into distilled water for ultrasonic treatment for 0.5-1h, wherein the proportion of the nanocrystal core to the distilled water is 1 mmol: (20-30) ml; then sequentially dropwise adding 1mol/L TiCl4And Ln(NO3)3(Ln = La, Gd, Lu) solution, stirring continuously for 1 h;
(6) and transferring the mixed solution into a high-pressure reaction kettle, reacting for 30-40h under the hydrothermal condition of 120-160 ℃, cooling to room temperature, washing the obtained precipitate with distilled water and absolute ethyl alcohol, carrying out centrifugal separation, and drying for 24h at 65 ℃. And finally, calcining the powder in an air atmosphere at the temperature of 550-650 ℃ for 2-3h to obtain the final product.
Preferably, Pr in step (5)3+:Ln2Ti2O7Nanocrystal core with TiCl4、Ln(NO3)3The molar ratio of the added amount of the solution is 1: (0.5-3): (0.5-3), and TiCl4And Ln (NO)3)3Is 1: 1.
Compared with the prior art, the invention has the beneficial effects that:
the core-shell nanocrystalline powder provided by the invention has the advantages that at room temperature, in the process of increasing the wavelength of exciting light from 312nm to 397nm, Pr is3+The red light (575-675 nm) emission intensity of the ions is gradually reduced, the blue-green light (465-520 nm) emission intensity is continuously enhanced, and Ln in the blue-violet region2Ti2O7The intensity of the (Ln = La, Gd, Lu) matrix defect emission band (420-455nm) is reduced from weak to strong, so that the fluorescence color is correspondingly changed from red light to pink light and finally to blue light. This is mainly due to Ln of the core-shell nanocrystals2Ti2O7(Ln = La, Gd, Lu) matrix defect luminescence, Pr3+The excitation spectrum of blue-green light and red light is continuously changed in the near ultraviolet to purple light region. Therefore, the fluorescence color of the nanocrystal of the invention can be changed only by changing the wavelength of the excitation light without the need of complicated adjustment of chemical components, crystal structures or combination with other phosphors. On the other hand, under excitation of 341nm exciting light, when the temperature is increased from room temperature to 300 ℃, the fluorescence color of the core-shell nanocrystal is converted into near white light from red light, and the change of chemical components, crystal structures and surface structures does not occur in the whole process. This is mainly due to Ln as the temperature increases2Ti2O7(Ln = La, Gd, Lu) matrix defectTrapped luminescence and Pr3+The blue-green light intensity of (A) is kept substantially constant, but Pr3+The red emission intensity of the ions gradually decreases, causing the fluorescent color to have a temperature dependent characteristic.
Drawings
FIG. 1 is a graph of the room temperature emission spectra of the core-shell nanocrystals of example 1 under excitation at different excitation wavelengths;
FIG. 2 is a graph of the CIE chromaticity values of the core-shell nanocrystals of example 1 as a function of the wavelength of the excitation light;
FIG. 3 temperature swing emission spectrum (341 nm excitation) of core-shell nanocrystals in example 1;
FIG. 4 is a graph of the CIE chromaticity values versus temperature for the core-shell nanocrystals of example 1 (341 nm excitation).
Detailed Description
The invention is further illustrated by the following examples
Example 1
15ml of emulsifier OP-10, 10ml of n-butanol and 60ml of cyclohexane were added to the flask, and the mixture was magnetically stirred at room temperature for 30min to obtain a reverse micelle system for use. 10ml of 1mol/L TiCl are added4The solution is dripped into a prepared reverse micelle system drop by drop, and magnetic stirring is carried out in a water bath at 50 ℃ for 1h to obtain TiCl4And (3) micro-emulsion. Preparing 10ml Pr (NO) by the same method3)3And 95ml Gd (NO)3)3And (3) micro-emulsion. 94.81ml of TiCl are added4Microemulsion with 94.81ml Gd (NO)3)3Mixing the micro-emulsions; then 0.095ml Pr (NO) is added dropwise3)3The microemulsion is stirred for 1 hour at room temperature; adjusting the pH value of the microemulsion to 6 by using ammonia water, and stirring for 30min to form light yellow green microemulsion; carrying out ultrasonic treatment on the microemulsion for 30min, then placing the microemulsion into a high-pressure reaction kettle, carrying out hydrothermal treatment for 5h at the temperature of 140 ℃, and then cooling to room temperature; washing the hydrothermal reaction product with isopropanol and anhydrous ethanol, centrifuging, drying the obtained precipitate at 60 deg.C for 15h, calcining at 550 deg.C for 1h to obtain 0.2mol% Pr3+:Gd2Ti2O7A nanocrystal core. Dispersing the nanocrystal core into 150ml of distilled water for 1h of ultrasonic treatment, and then adding 5ml of TiCl dropwise in sequence4(1mol/L) and 5ml Gd(NO3)3(1mol/L) solution, stirring for 1 h. Transferring the mixed solution into a high-pressure reaction kettle, reacting for 40h under the hydrothermal condition of 120 ℃, cooling to room temperature, washing the obtained precipitate with distilled water and absolute ethyl alcohol, centrifugally separating, and drying for 24h at 65 ℃. And calcining the dried powder at 550 ℃ for 3h in an air atmosphere to obtain the final product.
The observation of a transmission electron microscope shows that the synthesized core-shell nanocrystal is spherical particles with the average diameter of 30 nm. The fluorescent material is subjected to room temperature fluorescence spectrum detection, as can be seen from figure 1, and Pr is excited under the excitation of light at 312nm3+The emission wavelengths of (1) are at 597, 617, 630, 642, 645nm, wherein the peak intensity at 617nm is highest. Under 338nm light excitation, except Pr3+In the blue-violet region, Gd is present2Ti2O7Matrix Defect luminescence (peak 429nm) and Pr3+Blue green light emission (peak 486 nm). When excited by 350nm light, the matrix defect emits light and Pr3+The blue-green light emission intensity of (1) is continuously enhanced, therefore(blue-violet + blue-green)/IRed lightThe strength ratio increases. Pr under 397nm light excitation3+The blue-green light emission of the compound is remarkably enhanced, and meanwhile, Pr3+Red light and Gd of2Ti2O7The luminescence of the matrix defects is relatively weakened. As can be seen from fig. 2, the sample CIE chromaticity values changed from red light (0.6213, 0.3157) to pink light and finally blue light (0.2425, 0.2572) as the wavelength of the excitation light increased. On the other hand, under excitation of 341nm excitation light, the red fluorescence intensity gradually weakens in the process that the temperature of the sample gradually rises from room temperature to 300 ℃, and the blue-violet fluorescence intensity and the blue-green fluorescence intensity are basically kept unchanged, so that the CIE chromaticity value is converted from red light (0.5666, 0.3122) to near-white light (0.3258, 0.2709).
Example 2
15ml of emulsifier OP-10, 10ml of n-butanol and 80ml of cyclohexane are added into the flask, and the mixture is magnetically stirred for 30min at room temperature to obtain a reverse micelle system for later use. 10.5 ml of 1mol/L TiCl are added4The solution is dripped into a reverse micelle system drop by drop, and magnetic stirring is carried out in a water bath at 50 ℃ for 2 hours to obtain TiCl4And (3) micro-emulsion. In the same way, respectivelyThe preparation of 10ml Pr (NO)3)3And 115.5ml Gd (NO)3)3And (3) micro-emulsion. 105.6ml of TiCl are added4Microemulsion with 105.6ml Gd (NO)3)3Mixing the micro-emulsions; then, 2.2ml of Pr (NO) was added dropwise3)3Stirring the microemulsion for 1 hour at room temperature, adjusting the pH value of the microemulsion to 6 by using ammonia water, and stirring for 30min to form a yellow-green microemulsion; carrying out ultrasonic treatment on the microemulsion for 30min, then placing the microemulsion into a high-pressure reaction kettle, carrying out hydro-thermal treatment at 170 ℃ for 2h, and then cooling to room temperature; washing the hydrothermal reaction product with isopropanol and anhydrous ethanol, centrifuging, drying the obtained precipitate at 80 deg.C for 10 hr, calcining at 550 deg.C for 1 hr to obtain 4mol% Pr3+:Gd2Ti2O7A nanocrystal core. Dispersing the nanocrystal core into 100ml of distilled water for 1h of ultrasonic treatment, and then sequentially dropwise adding 30ml of TiCl4(1mol/L) and 30ml Gd (NO)3)3(1mol/L) solution, stirring for 1 h. Transferring the mixed solution into a high-pressure reaction kettle, reacting for 30h under the hydrothermal condition of 160 ℃, cooling to room temperature, washing the obtained precipitate with distilled water and absolute ethyl alcohol, centrifugally separating, and drying for 24h at 65 ℃. And calcining the dried powder at 650 ℃ for 2h in an air atmosphere to obtain the final product.
The observation of a transmission electron microscope shows that the synthesized core-shell nanocrystal is spherical particles with the average diameter of 60 nm. Detecting with room temperature fluorescence spectrum, and exciting with 312nm excitation wavelength light to obtain Pr3+The emission peak of (A) is mainly located in the red region, and the strongest peak is 617 nm. Under 338nm light excitation, Gd in the blue-violet region appears in addition to red light2Ti2O7Matrix Defect luminescence (peak 429nm) and Pr3+Blue-green light emission (peak 487 nm). Pr as the wavelength of the excitation light increases3+Blue-green light enhancement of Gd2Ti2O7Matrix defect luminescence and Pr3+The red light of (2) is continuously attenuated. Thus, as the excitation light wavelength increases from 312nm to 397nm, the sample CIE chromaticity values change from red (0.6316, 0.3191) to pink and finally blue (0.2456, 0.2619). On the other hand, under the excitation of 341nm exciting light, the red fluorescence of the sample gradually rises from room temperature to 300 DEG CThe light intensity gradually decreases, the blue-violet light and the blue-green light intensity basically keep unchanged, and the CIE chromaticity value is converted from red light (0.5568, 0.2933) to near-white light (0.3184, 0.2828).
Example 3
15ml of emulsifier OP-10, 10ml of n-butanol and 75ml of cyclohexane were added to the flask, and the mixture was magnetically stirred at room temperature for 30min to obtain a reverse micelle system for use. 10ml of 1mol/L TiCl are added4The solution is dripped into a reverse micelle system drop by drop, and magnetic stirring is carried out in a water bath at 50 ℃ for 2 hours to obtain TiCl4And (3) micro-emulsion. Preparing 10ml Pr (NO) by the same method3)3And 100ml La (NO)3)3And (3) micro-emulsion. 99ml of TiCl are added4Microemulsion with 99ml La (NO)3)3Mixing the micro-emulsions; then 0.5ml of Pr (NO) is added dropwise3)3The microemulsion is stirred for 1 hour at room temperature; adjusting the pH value of the microemulsion to 6 by using ammonia water, and stirring for 30min to form light yellow green microemulsion; the microemulsion is placed into a high-pressure reaction kettle after being subjected to ultrasonic treatment for 30min, and is cooled to room temperature after being subjected to hydrothermal treatment for 3.5h at 150 ℃; washing the hydrothermal reaction product with isopropanol and anhydrous ethanol, centrifuging, drying the precipitate at 70 deg.C for 12 hr, calcining at 550 deg.C for 1 hr to obtain 1mol% Pr3+:La2Ti2O7A nanocrystal core. Dispersing the nanocrystal core into 120ml of distilled water for 1h of ultrasonic treatment, and then adding 10ml of TiCl dropwise in sequence4(1mol/L) and 10ml of La (NO)3)3(1mol/L) solution, stirring for 1 h. Transferring the mixed solution into a high-pressure reaction kettle, reacting for 35h under the hydrothermal condition of 140 ℃, cooling to room temperature, washing the obtained precipitate with distilled water and absolute ethyl alcohol, centrifugally separating, and drying for 24h at 65 ℃. And calcining the dried powder at 600 ℃ for 2.5h in an air atmosphere to obtain the final product.
The observation of a transmission electron microscope shows that the synthesized core-shell nanocrystal is spherical particles with the average diameter of 54 nm. Detecting with room temperature fluorescence spectrum, and exciting with 312nm excitation wavelength light to obtain Pr3+The emission peak of (2) is mainly located in the red light region, and the strongest peak is 620 nm. Under the excitation of 338nm light, La in the blue-violet region appears in addition to red light2Ti2O7Matrix Defect luminescence (Peak 433 nm) and Pr3+Blue-green emission (peak 490 nm). Pr as the wavelength of the excitation light increases3+Blue-green light enhancement of La2Ti2O7Matrix defect luminescence and Pr3+The red light of (2) is continuously attenuated. Thus, as the excitation light wavelength increases from 312nm to 397nm, the sample CIE chromaticity values are converted from red (0.6275, 0.3088) to pink and finally blue (0.247, 0.2419). On the other hand, under excitation of 341nm exciting light, the red fluorescence intensity gradually weakens in the process that the temperature of the sample gradually rises from room temperature to 300 ℃, the blue-violet light intensity and the blue-green light intensity are basically kept unchanged, and the CIE chromatic value is converted from red light (0.5738, 0.2916) to near-white light (0.2673, 0.2662).
Example 4
15ml of emulsifier OP-10, 10ml of n-butanol and 70ml of cyclohexane were added to the flask, and the mixture was magnetically stirred at room temperature for 30min to obtain a reverse micelle system for use. 10ml of 1mol/L TiCl are added4The solution is dripped into a reverse micelle system drop by drop, and magnetic stirring is carried out in a water bath at 50 ℃ for 2 hours to obtain TiCl4And (3) micro-emulsion. Preparing 10ml Pr (NO) by the same method3)3And 105ml La (NO)3)3And (3) micro-emulsion. 103.73ml TiCl are added4Microemulsion with 103.73ml La (NO)3)3Mixing the micro-emulsions; then, 1.575ml of Pr (NO) is added dropwise3)3The microemulsion is stirred for 1 hour at room temperature; adjusting the pH value of the microemulsion to 6 by using ammonia water, and stirring for 30min to form a yellow-green microemulsion; carrying out ultrasonic treatment on the microemulsion for 30min, then placing the microemulsion into a high-pressure reaction kettle, carrying out hydrothermal treatment at 160 ℃ for 4h, and then cooling to room temperature; washing the hydrothermal reaction product with isopropanol and anhydrous ethanol, centrifuging, drying the precipitate at 70 deg.C for 12 hr, calcining at 550 deg.C for 1 hr to obtain 3mol% Pr3+:La2Ti2O7A nanocrystal core. Dispersing the nanocrystal core into 125ml of distilled water for 1h of ultrasonic treatment, and then adding 20ml of TiCl dropwise in sequence4(1mol/L) and 20ml of La (NO)3)3(1mol/L) solution, stirring for 1 h. Transferring the mixed solution into a high-pressure reaction kettle, reacting for 35h under the hydrothermal condition of 130 ℃, cooling to room temperature, adding distilled water andthe obtained precipitate was washed with absolute ethanol, centrifuged, and dried at 65 ℃ for 24 hours. And calcining the dried powder at 620 ℃ for 2.5h in an air atmosphere to obtain the final product.
The observation of a transmission electron microscope shows that the synthesized core-shell nanocrystal is spherical particles with the average diameter of 45 nm. Detecting with room temperature fluorescence spectrum, and exciting with 312nm excitation wavelength light to obtain Pr3+The emission peak of (2) is mainly located in the red light region, and the strongest peak is 620 nm. Under the excitation of 338nm light, La in the blue-violet region appears in addition to red light2Ti2O7Matrix Defect luminescence (Peak 433 nm) and Pr3+Blue-green emission (peak 490 nm). Pr as the wavelength of the excitation light increases3+The blue-green light is enhanced, and the blue-violet light and the red light are continuously weakened. Thus, as the excitation light wavelength increases from 312nm to 397nm, the sample changes the CIE chromaticity values from red (0.6312, 0.3172) to pink and finally blue (0.2422, 0.1969). On the other hand, under excitation of 341nm exciting light, the red fluorescence intensity gradually weakens in the process that the temperature of the sample gradually rises from room temperature to 300 ℃, the blue-violet light intensity and the blue-green light intensity are basically kept unchanged, and the CIE chromatic value is converted from red light (0.5867, 0.3182) to near-white light (0.3264, 0.2886).
Example 5
15ml of emulsifier OP-10, 10ml of n-butanol and 70ml of cyclohexane were added to the flask, and the mixture was magnetically stirred at room temperature for 30min to obtain a reverse micelle system for use. 10ml of 1mol/L TiCl are added4The solution is dripped into a reverse micelle system drop by drop, and magnetic stirring is carried out in a water bath at 50 ℃ for 2 hours to obtain TiCl4And (3) micro-emulsion. Preparing 10ml Pr (NO) by the same method3)3And 105ml Lu (NO)3)3And (3) micro-emulsion. 104.475ml TiCl are added4Microemulsion with 104.475ml Lu (NO)3)3Mixing the micro-emulsions; then 0.263ml of Pr (NO) is added dropwise3)3The microemulsion is stirred for 1 hour at room temperature; adjusting the pH value of the microemulsion to 6 by using ammonia water, and stirring for 30min to form light yellow green microemulsion; carrying out ultrasonic treatment on the microemulsion for 30min, then placing the microemulsion into a high-pressure reaction kettle, carrying out hydrothermal treatment at 160 ℃ for 4h, and then cooling to room temperature; the hydrothermal reaction product is treated with isopropanolWashing with water and ethanol, centrifuging, drying the precipitate at 70 deg.C for 12 hr, calcining at 550 deg.C for 1 hr to obtain 0.5mol% Pr3+:Lu2Ti2O7A nanocrystal core. Dispersing the nanocrystal core into 125ml of distilled water for 1h of ultrasonic treatment, and then sequentially dropwise adding 25ml of TiCl4(1mol/L) and 25ml Lu (NO)3)3(1mol/L) solution, stirring for 1 h. Transferring the mixed solution into a high-pressure reaction kettle, reacting for 32 hours at 140 ℃ under a hydrothermal condition, cooling to room temperature, washing the obtained precipitate with distilled water and absolute ethyl alcohol, centrifugally separating, and drying for 24 hours at 65 ℃. And calcining the dried powder at 610 ℃ for 2.5h in an air atmosphere to obtain the final product.
The observation of a transmission electron microscope shows that the synthesized core-shell nanocrystal is spherical particles with the average diameter of 56 nm. Detecting with room temperature fluorescence spectrum, and exciting with 312nm excitation wavelength light to obtain Pr3+The emission peak of (A) is mainly located in the red light region, and the strongest peak is 612 nm. Under the excitation of 338nm light, besides red light, Lu in the blue-violet region appears2Ti2O7Matrix defect luminescence (peak 425 nm) and Pr3+Blue-green light emission (peak 484 nm). Pr as the wavelength of the excitation light increases3+The blue-green light is enhanced, and the blue-violet light and the red light are continuously weakened. Thus, as the excitation light wavelength increased from 312nm to 397nm, the sample CIE chromaticity values were converted from red (0.6248, 0.3175) to blue (0.2052, 0.2396). On the other hand, under excitation of 341nm excitation light, the red fluorescence intensity gradually weakens in the process that the temperature of the sample gradually rises from room temperature to 300 ℃, the blue-violet light intensity and the blue-green light intensity are basically kept unchanged, and the CIE chromaticity value is converted from red light (0.5618, 0.2962) to near-white light (0.2948, 0.257).
Example 6
15ml of emulsifier OP-10, 10ml of n-butanol and 80ml of cyclohexane were added to the flask, and the mixture was magnetically stirred at room temperature for 30min to obtain a reverse micelle system for use. 10.5 ml of 1mol/L TiCl are added4The solution is dripped into a reverse micelle system drop by drop, and magnetic stirring is carried out in a water bath at 50 ℃ for 2 hours to obtain TiCl4And (3) micro-emulsion. Preparing 10ml Pr (NO) by the same method3)3And 115.5ml Lu (NO)3)3And (3) micro-emulsion. 107.8ml of TiCl are added4Microemulsion with 107.8ml Lu (NO)3)3Mixing the micro-emulsions; then, 1.1 ml of Pr (NO) was added dropwise3)3The microemulsion is stirred for 1 hour at room temperature; adjusting the pH value of the microemulsion to 6 by using ammonia water, and stirring for 30min to form a yellow-green microemulsion; carrying out ultrasonic treatment on the microemulsion for 30min, then placing the microemulsion into a high-pressure reaction kettle, carrying out hydrothermal treatment at 150 ℃ for 3h, and then cooling to room temperature; washing the hydrothermal reaction product with isopropanol and anhydrous ethanol, centrifuging, drying the precipitate at 75 deg.C for 9 hr, calcining at 550 deg.C for 1 hr to obtain 2mol% Pr3+:Lu2Ti2O7A nanocrystal core. Dispersing the nanocrystal core into 100ml of distilled water for 1h of ultrasonic treatment, and then sequentially dropwise adding 15ml of TiCl4(1mol/L) and 15ml Lu (NO)3)3(1mol/L) solution, stirring for 1 h. Transferring the mixed solution into a high-pressure reaction kettle, reacting for 33h under the hydrothermal condition of 145 ℃, cooling to room temperature, washing the obtained precipitate with distilled water and absolute ethyl alcohol, centrifugally separating, and drying for 24h at 65 ℃. And calcining the dried powder at 580 ℃ for 2.5 hours in an air atmosphere to obtain the final product.
The observation of a transmission electron microscope shows that the synthesized core-shell nanocrystal is spherical particles with the average diameter of 47 nm. Detecting with room temperature fluorescence spectrum, and exciting with 312nm excitation wavelength light to obtain Pr3+The emission peak of (A) is mainly located in the red light region, and the strongest peak is 612 nm. Under the excitation of 338nm light, besides red light, Lu in the blue-violet region appears2Ti2O7Matrix defect luminescence (peak 425 nm) and Pr3+Blue green light emission (peak 485 nm). Pr as the wavelength of the excitation light increases3+The blue-green light is enhanced, and the blue-violet light and the red light are continuously weakened. Thus, as the excitation light wavelength was increased from 312nm to 397nm, the sample CIE chromaticity values were converted from red (0.6265, 0.3183) to blue (0.226, 0.2558). On the other hand, under excitation of 341nm exciting light, in the process that the temperature of the sample is gradually increased from room temperature to 300 ℃, the fluorescence intensity of red light is gradually weakened, the intensity of blue-violet light and blue-green light is basically kept unchanged, and the CIE chromatic value is changed from red light (0.5668,0.3122) into near white light (0.2586, 0.2537).
Claims (7)
1. A fluorescence adjustable core-shell nanocrystal is characterized in that the core-shell nanocrystal consists of Pr3+:Ln2Ti2O7＠Ln2Ti2O7Ln = La, Gd, Lu, the crystal nucleus composition of which is Pr3+:Ln2Ti2O7Ln = La, Gd, Lu, the shell coating the outer surface of the crystal nucleus is the same Ln2Ti2O7，Ln=La, Gd, Lu。
2. The fluorescence tunable core-shell nanocrystal of claim 1, wherein the Pr is3+The ion doping concentration is 0.2-4 mol%.
3. The fluorescence-tunable core-shell nanocrystal of claim 1, wherein: the core-shell nanocrystal is spherical, and the average diameter of the core-shell nanocrystal is 30-60 nm.
4. The fluorescence adjustable core-shell nanocrystal as claimed in claim 1, wherein at room temperature, when the wavelength of the excitation light is increased from 312nm to 397nm, the color adjustable emission from red light → pink light → blue light can be realized, and the fluorescence adjustable core-shell nanocrystal has application prospects in the fields of LED semiconductor illumination, display devices and biological imaging.
5. The fluorescence adjustable core-shell nanocrystal as claimed in claim 1, wherein under excitation of 341nm excitation light, when the temperature is increased from room temperature to 300 ℃, the color adjustable emission from red light → pink light → near white light can be realized, and the fluorescence adjustable core-shell nanocrystal has application potential in the aspect of high temperature early warning display devices.
6. The method for preparing fluorescence-tunable nanocrystal according to any of claims 1 to 3, characterized by the following steps:
(1) adding a certain amount of emulsifier OP-10, n-butanol and cyclohexane into the flask, wherein the proportion relationship is 3 ml: 2 ml: 12-16 ml; magnetically stirring at room temperature for 30min to uniformly mix the components to obtain a reverse micelle system for later use;
(2) TiCl with a concentration of 1mol/L4Dropwise adding the solution into the reverse micelle system prepared in the step (1) by drops, wherein TiCl4The volume ratio of the solution to the reverse micelle system is 1 ml: 9-10 ml; magnetically stirring in water bath at 50 deg.C for 1-2 hr to obtain TiCl4Micro-emulsion; in the same way, Pr (NO) is prepared separately3)3And Ln (NO)3)3Ln = La, Gd, Lu microemulsion;
(3) TiCl in the step (2)4Microemulsion with Ln (NO)3)3Ln = La, Gd, Lu microemulsions are mixed in a volume ratio of 1: 1; adding Pr (NO) with a certain molar weight proportion3)3The microemulsion is stirred for 1 hour at room temperature; adjusting the pH value of the microemulsion to 6 by using ammonia water, and stirring for 30min to form a yellow-green microemulsion;
(4) carrying out ultrasonic treatment on the microemulsion in the step (3) for 30min, then placing the microemulsion into a high-pressure reaction kettle, carrying out hydro-thermal treatment at the temperature of 140-; washing a product obtained by the hydrothermal reaction with isopropanol and absolute ethyl alcohol, and performing centrifugal separation; drying the obtained precipitate at 60-80 ℃ for 10-15h, and calcining at 550 ℃ for 1h in air atmosphere to obtain the required nanocrystal core;
(5) weighing the Pr in the step (4)3+:Ln2Ti2O7Dispersing the nanocrystal core into distilled water for ultrasonic treatment for 0.5-1h, wherein the proportion of the nanocrystal core to the distilled water is 1 mmol: 20-30 ml; then sequentially dropwise adding 1mol/L TiCl4And Ln (NO)3)3Ln = La, Gd, Lu solution, stirring continuously for 1 h;
(6) transferring the mixed solution obtained in the step (5) into a high-pressure reaction kettle, reacting for 30-40h under the hydrothermal condition of 120-160 ℃, cooling to room temperature, washing the obtained precipitate with distilled water and absolute ethyl alcohol, performing centrifugal separation, and drying for 24h at 65 ℃; and finally, calcining the powder in an air atmosphere at the temperature of 550-650 ℃ for 2-3h to obtain the final product.
7. The method for preparing fluorescence-tunable core-shell nanocrystals according to claim 6, wherein Pr in step (5) is3+:Ln2Ti2O7Nanocrystal core with TiCl4、Ln(NO3)3The molar ratio of the added amount of the solution is 1: 0.5-3:0.5-3, and TiCl4And Ln (NO)3)3Is 1: 1.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810479184.2A CN108531180B (en) | 2018-05-18 | 2018-05-18 | Fluorescence adjustable core-shell nanocrystal and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810479184.2A CN108531180B (en) | 2018-05-18 | 2018-05-18 | Fluorescence adjustable core-shell nanocrystal and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN108531180A CN108531180A (en) | 2018-09-14 |
| CN108531180B true CN108531180B (en) | 2020-12-08 |
Family
ID=63472311
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810479184.2A Active CN108531180B (en) | 2018-05-18 | 2018-05-18 | Fluorescence adjustable core-shell nanocrystal and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN108531180B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110452701B (en) * | 2019-08-21 | 2022-07-26 | 哈尔滨学院 | Method for finely adjusting chromaticity by mixing based on rare earth doped up-conversion nanocrystalline |
| CN113797765B (en) * | 2020-06-12 | 2022-11-08 | 三达膜科技（厦门）有限公司 | Preparation method of zirconia ceramic ultrafiltration membrane |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101974329B (en) * | 2010-10-08 | 2013-12-11 | 东华大学 | La2Ti2O7:Sm3+ red phosphor and preparation method thereof |
| CN102559172A (en) * | 2011-11-29 | 2012-07-11 | 天津理工大学 | Semiconductor luminescent material with adjustable luminescent colours and preparation method |
| CN104059653B (en) * | 2013-03-20 | 2017-01-25 | 海洋王照明科技股份有限公司 | yttrium titanate luminescent material and preparation method thereof |
| CN107603594A (en) * | 2017-09-08 | 2018-01-19 | 东华理工大学 | Prepare Y2Ti2O7@SiO2The method of core-shell structure up-conversion |
-
2018
- 2018-05-18 CN CN201810479184.2A patent/CN108531180B/en active Active
Also Published As
| Publication number | Publication date |
|---|---|
| CN108531180A (en) | 2018-09-14 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Gai et al. | Monodisperse Gd2O3: Ln (Ln= Eu3+, Tb3+, Dy3+, Sm3+, Yb3+/Er3+, Yb3+/Tm3+, and Yb3+/Ho3+) nanocrystals with tunable size and multicolor luminescent properties | |
| Luwang et al. | Preparation of white light emitting YVO 4: Ln 3+ and silica-coated YVO 4: Ln 3+(Ln 3+= Eu 3+, Dy 3+, Tm 3+) nanoparticles by CTAB/n-butanol/hexane/water microemulsion route: energy transfer and site symmetry studies | |
| CN106544025B (en) | A kind of preparation method of rear-earth-doped gadolinium oxysulfide fluorescent powder | |
| Xu et al. | Controlled synthesis of single-crystal SrAl2O4: Eu2+, Dy3+ nanosheets with long-lasting phosphorescence | |
| Guo et al. | Luminescent properties of R2 (MoO4) 3: Eu3+ (R= La, Y, Gd) phosphors prepared by sol–gel process | |
| Lu et al. | Nanosized strontium aluminate phosphors prepared via a reverse microemulsion route | |
| Yuan et al. | Highly efficient carbon dots and their nanohybrids for trichromatic white LEDs | |
| CN112680213B (en) | Preparation method of perovskite nanocrystal coated by tetraethoxysilane | |
| Li et al. | Carbon nanodots enhance and optimize the photoluminescence of micro-spherical YBO3: Eu3+ phosphors | |
| CN108531180B (en) | Fluorescence adjustable core-shell nanocrystal and preparation method thereof | |
| Ramteke et al. | Eu3+ and Dy3+-activated LaAlO3 phosphor for solid-state lighting | |
| Liu et al. | Multifunctional β-NaGdF4: Ln3+ (Ln= Yb/Er/Eu) phosphors synthesized by L-arginine assisted hydrothermal method and their multicolor tunable luminescence | |
| Bohus et al. | Structural and luminescence properties of Y2O3: Eu3+ core–shell nanoparticles | |
| Liu et al. | Spherical red-emitting X1-Y2SiO5: Eu and α-Y2Si2O7: Eu phosphors with high color purity: The evolution of morphology, phase and photoluminescence upon annealing | |
| Liu et al. | Multi-site occupancies and luminescence properties of cyan-emitting Ca9–xNaGd2/3 (PO4) 7: Eu2+ phosphors for white light-emitting diodes | |
| CN103275715B (en) | Preparation method of rare earth molybdate matrix red nanophosphor | |
| Duan et al. | Synthesis process dependent white LPL in Zn2GeO4 ceramic and the long afterglow mechanism | |
| CN113913184B (en) | Rare earth co-doped gallium oxide fluorescent material and preparation method and application thereof | |
| Sun et al. | Improved moisture resistance of SrSO4: Sm3+ phosphors coated with SiO2 | |
| El Ghoul et al. | Effect of annealing temperature on the luminescence properties of Zn2SiO4: V nanocomposite | |
| CN101914379B (en) | Method for preparing nitrogen oxide phosphor powder | |
| Zhai et al. | PEG-assisted hydrothermal synthesis and luminescent properties of ZnWO 4: Sm 3+ white light-emitting phosphors | |
| Liu et al. | Highly efficient and stable red perovskite quantum dots through encapsulation and sensitization of porous CaF 2: Ce, Tb nanoarchitectures | |
| Han et al. | CTAB-assisted precipitation synthesis and photoluminescence properties of olive-like YVO4: Eu nanocrystallites | |
| Alcaraz et al. | Influence of the synthesis conditions of Y 0.9 Dy 0.1 VO 4 and silica-coated Y 0.9 Dy 0.1 VO 4 nanophosphors on the powder morphology and luminescence emission intensity |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |