A rare earth-doped indium phosphide blue light quantum dot and a preparation method thereof

Abstract

The present application discloses a rare earth-doped indium phosphide blue light quantum dot and a preparation method thereof. On the one hand, the present application provides a rare earth-doped indium phosphide blue light quantum dot. The indium phosphide blue light quantum dot adopts a core-shell structure formed on the basis of quantum dots, and includes an indium phosphide crystal nucleus doped with neodymium element and an external zinc sulfide shell layer. On the other hand, the present application also provides a preparation method of the above rare earth-doped indium phosphide blue light quantum dot. The rare earth-doped indium phosphide blue light quantum dot of the present application has excellent optical properties, and the emission wavelength is tunable in the range of 470-520 nm. The preparation process is simple, the conditions are mild, and it does not contain heavy metal toxic elements.

Description

Technical Field

[0001] This application relates to the technical field of luminescent materials, and particularly to a rare earth-doped indium phosphide blue light quantum dot and a preparation method thereof. Background Art

[0002] Quantum dots (QDs) are a new type of inorganic fluorescent material with nanoscale dimensions and a series of unique properties. Since the size of quantum dots is less than or equivalent to the exciton Bohr radius of the material, electrons and holes are quantum-confined. And due to the limited number of atoms that make up quantum dots, the energy levels of the constructed material become discrete compared to bulk materials (similar to molecular energy levels and can produce photoluminescence), and the bandwidth becomes larger compared to bulk materials (the absorption spectrum and emission spectrum undergo a blue shift). Therefore, by reasonably designing and regulating parameters such as the size and morphology of semiconductors, new semiconductor nanomaterials with excellent optoelectronic properties can be obtained. The emergence of quantum dot materials provides a new idea for the design and preparation of high-performance semiconductor materials, that is, the size effect of materials can be used to regulate the optical and electrical properties of materials. However, existing high-performance quantum dot materials usually contain highly toxic elements such as cadmium or lead. The large-scale preparation and use of such materials are not only harmful to the human body but also cause environmental pollution. Therefore, it is very urgent to develop quantum dot materials with low toxicity, low pollution, and high performance.

[0003] Indium phosphide quantum dot materials have low toxicity (without heavy metal toxic elements such as lead and cadmium), and have excellent luminescent properties. The fluorescence emission peak is adjustable in the visible to near-infrared emission range, with a high fluorescence quantum yield and good stability, and has broad application prospects in new luminescent devices, display devices, optical detection devices, and biological fluorescence imaging. Currently, breakthroughs have been made in red and green indium phosphide quantum dot materials, with their fluorescence quantum yield (PLQY) approaching 100% and the full width at half maximum (FWHM) of the emission being nearly 30 nm. However, the current performance of blue indium phosphide quantum dot materials is poor, especially in the deep blue light field, which severely restricts the development of indium phosphide quantum dot materials in the full-color display field.

[0004] Introducing impurity ions during the preparation process of quantum dots is an effective means to improve their performance. By introducing doping ions such as Cu 2+ , Mn 2+ , Ag + and Ga 3+ ions during the InP synthesis process, the luminescence characteristics of indium phosphide quantum dots can be effectively improved. However, the currently widely used ion types and doping methods cannot obtain blue indium phosphide quantum dots with excellent performance.

[0005] Therefore, developing a blue indium phosphide quantum dot material with excellent performance has become a technical problem that urgently needs to be solved. Summary of the Invention

[0006] To solve at least one of the above technical problems, a blue light indium phosphide quantum dot material with a tunable emission wavelength in the range of 470 - 520 nm, simple preparation process, mild conditions, and no heavy metal toxic elements is developed. This application provides a rare earth doped indium phosphide blue light quantum dot and its preparation method.

[0007] On the one hand, this application provides a rare earth doped indium phosphide blue light quantum dot. The indium phosphide blue light quantum dot adopts a core - shell structure formed on the basis of quantum dots, including an indium phosphide crystal nucleus doped with neodymium element and an external zinc sulfide shell layer.

[0008] By adopting the above technical solution, the quantum dot with a core - shell structure is used in this application, which can effectively improve the optical performance and stability of the indium phosphide blue light quantum dot; meanwhile, this application adopts a zinc sulfide shell layer with strong chemical stability and a relatively wide bandgap, which can effectively improve the quantum confinement effect; this application is doped with neodymium element, effectively solving the problems of low fluorescence quantum yield and emission wavelength only located in the range of light blue light existing in the blue light indium phosphide blue light quantum dot prepared by the prior art. The emission wavelength can cover the range of deep blue light, and can also effectively improve the optical performance of the indium phosphide quantum dot; this application introduces neodymium element and simultaneously adopts a zinc sulfide shell layer. By adjusting the addition amount of neodymium element and zinc element, the emission wavelength can be tuned in the range of 470 - 520 nm.

[0009] Optionally, in the indium phosphide blue light quantum dot, the molar ratio of indium element to neodymium element is 1:0.1 - 4.

[0010] Optionally, in the indium phosphide blue light quantum dot, the molar ratio of indium element to zinc element is 1:n, where 0 < n ≤ 7.

[0011] By adopting the above technical solution, more precise control of the addition amount of neodymium element and zinc element can further improve the optical performance of the prepared indium phosphide blue light quantum dot, and at the same time, the emission wavelength can be controlled in the range of 470 - 520 nm.

[0012] On the other hand, this application also provides a preparation method of the above rare earth doped indium phosphide blue light quantum dot, including the following steps:

[0013] S1. At the first temperature, add an indium precursor, rare earth neodymium, and a zinc precursor to a non - coordinating solvent, remove oxygen from the solution, mix evenly to obtain an indium precursor mixed solution, and keep it at the first temperature for standby;

[0014] S2. At the second temperature, inject a phosphorus source into the indium precursor mixed solution prepared in step S1, and keep it for more than 5 minutes to obtain an indium phosphide mixed solution;

[0015] S3. Inject a sulfur precursor into the indium phosphide mixed solution obtained in step S2, heat it up to a third temperature, and react to form indium phosphide quantum dots with a core-shell structure. After separation and purification, rare-earth doped indium phosphide blue-light quantum dots are obtained.

[0016] By adopting the above technical solution, the preparation process of the present application is relatively simple. Only by using the methods of mixing and heating reaction, rare-earth doped indium phosphide blue-light quantum dots can be prepared. The process conditions are mild and easy to control. The process of the present application is highly repeatable, and can stably prepare rare-earth doped indium phosphide blue-light quantum dots with excellent optical properties, which is easy to prepare in batches and easy to promote. The preparation method of the present application does not contain heavy metal toxic elements and is green and environmentally friendly.

[0017] Optionally, the first temperature is 80-140 °C; the second temperature is 180-230 °C; the third temperature is 200-300 °C.

[0018] By adopting the above technical solution, the present application precisely controls the temperature of each step, which can effectively guarantee the yield and the quality of the finished product. At the same time, the reaction temperature adopted by the present application is relatively low, the process conditions are mild, and it is easy to control.

[0019] Optionally, in step S1, the solvent adopts a mixed solution of oleylamine and octadecene.

[0020] Optionally, in step S1, the indium precursor is selected from one or more of indium chloride, indium bromide and indium iodide; the neodymium precursor adopts neodymium acetylacetonate; the zinc precursor is selected from one or more of zinc chloride, zinc bromide and zinc iodide.

[0021] Optionally, in step S2, the phosphorus source adopts tris(dimethylamino)phosphine; the phosphorus source is added in an amount of 1 mL or more per 1 mmol of indium precursor.

[0022] Optionally, in step S3, the sulfur precursor adopts n-dodecyl mercaptan.

[0023] By adopting the above technical solution, each raw material selected by the present application is easy to obtain, the cost is relatively low, and the selected raw materials have little environmental pollution, which can effectively reduce the preparation cost.

[0024] Optionally, steps S1 to S3 are all completed under the protection of a nitrogen atmosphere.

[0025] By adopting the above technical solution, the present application adopts a nitrogen atmosphere protection throughout the preparation process, which can effectively avoid the introduction of impurities and further guarantee the performance of the prepared quantum dot material.

[0026] In summary, the present invention includes at least one of the following beneficial technical effects:

[0027] 1. The present application uses quantum dots with a core-shell structure, which can effectively improve the optical performance and stability of indium phosphide blue light quantum dots. At the same time, the present application uses a zinc sulfide shell layer, which has strong chemical stability and a relatively wide bandgap, and can effectively improve the quantum confinement effect.

[0028] 2. The present application is doped with neodymium elements, which effectively solves the problems of low fluorescence quantum yield and the emission wavelength only being located in the range of light blue in the blue light indium phosphide quantum dots prepared by the prior art. The emission wavelength can cover the range of deep blue light, and can also effectively improve the optical performance of indium phosphide quantum dots.

[0029] 3. The present application introduces neodymium elements and at the same time uses a zinc sulfide shell layer. By adjusting the addition amount of neodymium elements and zinc elements, the emission wavelength can be tuned in the range of 470 - 520 nm.

[0030] 4. The preparation process of the present application is relatively simple. By only using the methods of mixing and heating reaction, rare earth-doped indium phosphide blue light quantum dots can be prepared. The process conditions are mild and easy to control. Moreover, the preparation method of the present application does not contain heavy metal toxic elements and is green and environmentally friendly.

[0031] 5. The process of the present application is highly repeatable, and can stably prepare rare earth-doped indium phosphide blue light quantum dots with excellent optical performance, which is easy to prepare in batches and easy to promote. Description of the Drawings

[0032] Figure 1 It is the fluorescence emission spectrum diagram of rare earth ion-doped InP QDs prepared in Example 1 of the present application;

[0033] Figure 2 It is the fluorescence emission spectrum diagram of rare earth ion-doped InP QDs prepared in Example 2 of the present invention;

[0034] Figure 3 It is the fluorescence emission spectrum diagram of rare earth ion-doped InP QDs prepared in Example 3 of the present invention;

[0035] Figure 4 It is the transmission electron microscope image of rare earth ion-doped InP QDs prepared in Example 2 of the present invention;

[0036] Figure 5 It is the XPS fluorescence emission spectrum diagram of rare earth ion-doped InP QDs prepared in Example 2 of the present invention;

[0037] Figure 6 It is the X-ray photoelectron energy spectrum diagram of neodymium elements of rare earth ion-doped InP QDs prepared in Example 2 of the present invention. Embodiments

[0038] The present application will be further described in detail below in conjunction with embodiments and the accompanying drawings.

[0039] Glossary: QDs - Quantum Dots, InPQDs - Indium Phosphide Quantum Dots, Nd(acac)3 - Neodymium Acetylacetonate, (DMA)3P - Tris(dimethylamino)Phosphine, DDT - n-Dodecyl Mercaptan.

[0040] The present application designs a rare earth ion-doped indium phosphide quantum dot, adopting a core-shell structure formed on the basis of quantum dots, including an indium phosphide crystal nucleus doped with neodymium element and an external zinc sulfide shell layer.

[0041] Prior to the present application, most indium phosphide quantum dot materials were red and green light quantum dot materials. In the prior art, the PLQY of red and green indium phosphide quantum dot materials was close to 100%, and the performance was also relatively excellent. However, blue indium phosphide quantum dot materials have rarely been reported in the prior art, and the PLQY is low, and the optical performance is also poor.

[0042] In the prior art, for the research and development of blue indium phosphide quantum dot materials, the method of designing a core-shell structure is mostly adopted. Through the core-shell structure, the fluorescence emission spectrum of indium phosphide quantum dots is located in the blue light range. For example, a Chinese invention patent with the publication number CN113956879A and the invention name of a blue indium phosphide quantum dot and its preparation method, an electroluminescent device and a display device discloses a blue indium phosphide quantum dot. However, its PLQY is below 80%, and the optical performance is also poor.

[0043] The inventors of the present application found through experimental research that after doping with neodymium element, the fluorescence emission spectrum of indium phosphide quantum dots can be located in the blue light range, and the optical performance is relatively excellent. The inventors designed the blue indium phosphide quantum dot material of the present application by doping with neodymium element and adopting a zinc sulfide shell layer to form a core-shell structure, and designed a preparation process with mild process conditions, which not only has excellent optical performance but also has a high PLQY.

[0044] The following are Examples 1 to 3 of the present application.

[0045] Example 1: This example provides a rare earth ion-doped indium phosphide quantum dot with an emission wavelength located at 488 nm, which is prepared by the following steps.

[0046] 1) Preparation of In precursor mixed solution:

[0047] Add 6 mL of OLA, 4 mL of ODE, 0.4 mmol of InCl3, 0.4 mmol of Nd(acac)3 and 1.2 mmol of ZnI2 into a three-necked flask; heat the mixed solution to 80 °C, and introduce N2 to remove water and oxygen for more than 30 min; then stir rapidly until the raw materials are completely dissolved to obtain a clear In precursor mixed solution, keep the solution at 80 °C for standby.

[0048] 2) Preparation of P precursor solution:

[0049] Prepare a P precursor solution using 0.4 mL of (DMA)3P as the P source for standby.

[0050] 3) Preparation of Nd-doped InP crystal nuclei:

[0051] Heat the In precursor mixed solution described in step 1) to 180 °C. At 180 °C, rapidly inject the P precursor solution prepared in step 2), keep warm for 10 min to form Nd-doped InP crystal nuclei, and obtain a solution containing the product of Nd-doped InP crystal nuclei.

[0052] 4) Preparation of S precursor solution:

[0053] Prepare an S precursor solution using 3 mL of DDT as the S source for standby.

[0054] 5) Preparation of Nd-doped core-shell structured InPQDs:

[0055] Heat the solution containing the product of Nd-doped InP crystal nuclei in step 3) to 200 °C. At 200 °C, rapidly inject the S precursor solution prepared in step 4), keep warm for 120 min to form Nd-doped core-shell structured InPQDs, and obtain a solution containing the product of Nd-doped core-shell structured InPQDs.

[0056] 6) Separation and purification of Nd-doped core-shell structured InPQDs:

[0057] Take 1 mL of the solution containing the product of Nd-doped core-shell structured InPQDs in step 5), dissolve it in 2 mL of n-hexane, add 8 mL of ethanol, centrifuge at 10000 r / pm for 5 min, take the precipitate and redisperse it in 5 mL of n-hexane to obtain purified Nd-doped core-shell structured InPQDs with an emission wavelength of 488 nm.

[0058] Detect the Nd-doped core-shell structured InPQDs of this example, and its fluorescence emission spectrum is as Figure 1 shown, with the emission wavelength located at 488 nm.

[0059] Example 2: This example provides rare earth ion-doped indium phosphide quantum dots with an emission wavelength of 481 nm, which are prepared by the following steps.

[0060] 1) Preparation of In precursor mixed solution:

[0061] Add 6 mL of OLA, 4 mL of ODE, 0.4 mmol of InBr3, 0.8 mmol of Nd(acac)3, and 1.2 mmol of ZnBr2 into a three-necked flask; heat the mixed solution to 120 °C, and introduce N2 to remove water and oxygen for more than 30 min, then stir rapidly until the raw materials are completely dissolved to obtain a clear In precursor mixed solution, and keep the solution at 120 °C for standby.

[0062] 2) Preparation of P precursor solution:

[0063] Use 0.4 mL of (DMA)3P as the P source to prepare the P precursor solution for standby.

[0064] 3) Preparation of Nd-doped InP crystal nuclei:

[0065] Heat the In precursor mixed solution described in step 1) to 200 °C. At 200 °C, rapidly inject the P precursor solution prepared in step 2), and keep warm for 10 min to form Nd-doped InP crystal nuclei, obtaining a solution containing the product of Nd-doped InP crystal nuclei.

[0066] 4) Preparation of S precursor solution:

[0067] Use 3 mL of DDT as the S source to prepare the S precursor solution for standby.

[0068] 5) Preparation of Nd-doped core-shell structured InPQDs:

[0069] Heat the solution containing the product of Nd-doped InP crystal nuclei in step 3) to 250 °C. At 250 °C, rapidly inject the S precursor solution prepared in step 4), and keep warm for 120 min to form Nd-doped core-shell structured InPQDs, obtaining a solution containing the product of Nd-doped core-shell structured InPQDs.

[0070] 6) The separation and purification of Nd-doped core-shell structured InPQDs are the same as those in Example 1.

[0071] Detect the Nd-doped core-shell structured InPQDs in this example, and its fluorescence emission spectrum is as Figure 2 shown, and the emission wavelength is located at 481 nm.

[0072] Conduct various detections on the Nd-doped core-shell structured InPQDs in Example 2 of this application. Its transmission electron microscope image is as Figure 4 shown, the XPS fluorescence emission spectrum is as Figure 5 shown, and the X-ray photoelectron energy spectrum of neodymium element is as Figure 6As shown. From the above test results, it can be seen that the performance of the Nd-doped core-shell structured InPQDs in this embodiment is very excellent.

[0073] Example 3: This example provides rare earth ion-doped indium phosphide quantum dots with an emission wavelength of 470 nm, which are prepared by the following steps.

[0074] 1) Preparation of In precursor mixed solution:

[0075] Add 6 mL of OLA, 4 mL of ODE, 0.4 mmol of InI3, 1.6 mmol of Nd(acac)3 and 2.4 mmol of ZnCl2 into a three-necked flask; heat the mixed solution to 140 °C, and introduce N2 to remove water and oxygen for more than 30 min; then stir rapidly until the raw materials are completely dissolved to obtain a clear In precursor mixed solution, and keep the solution at 140 °C for standby.

[0076] 2) Preparation of P precursor solution:

[0077] Use 0.4 mL of (DMA)3P as the P source to prepare the P precursor solution for standby.

[0078] 3) Preparation of Nd-doped InP crystal nuclei:

[0079] Heat the In precursor mixed solution described in step 1) to 230 °C. At 230 °C, rapidly inject the P precursor solution prepared in step 2), and keep warm for 10 min to form Nd-doped InP crystal nuclei, obtaining a solution containing the product of Nd-doped InP crystal nuclei.

[0080] 4) Preparation of S precursor solution:

[0081] Use 3 mL of DDT as the S source to prepare the S precursor solution for standby.

[0082] 5) Preparation of Nd-doped core-shell structured InPQDs:

[0083] Heat the solution containing the product of Nd-doped InP crystal nuclei in step 3) to 300 °C. At 300 °C, rapidly inject the S precursor solution prepared in step 4), and keep warm for 120 min to form Nd-doped core-shell structured InPQDs, obtaining a solution containing the product of Nd-doped core-shell structured InPQDs.

[0084] 6) The separation and purification of the Nd-doped core-shell structured InPQDs are the same as those in Example 1.

[0085] Detect the Nd-doped core-shell structured InPQDs in this example, and its fluorescence emission spectrum is as Figure 3 shown, and the emission wavelength is located at 470 nm.

[0086] The following are Examples 4 to 10 of the present application.

[0087] Example 4: This example provides a rare earth ion-doped indium phosphide quantum dot, which is prepared by the following steps.

[0088] 1) Preparation of In precursor mixed solution:

[0089] Add 4 mL of OLA, 6 mL of ODE, 0.4 mmol of InCl3, 0.4 mmol of Nd(acac)3 and 0.1 mmol of ZnBr2 into a three-necked flask; heat the mixed solution to 90 °C, and introduce N2 to remove water and oxygen for more than 30 min, then quickly stir until the raw materials are completely dissolved to obtain a clear In precursor mixed solution, and keep the solution at 90 °C for standby.

[0090] 2) Preparation of P precursor solution:

[0091] Use 0.4 mL of (DMA)3P as the P source to prepare the P precursor solution for standby.

[0092] 3) Preparation of Nd-doped InP crystal nuclei:

[0093] Heat the In precursor mixed solution described in step 1) to 190 °C, and quickly inject the P precursor solution prepared in step 2) at 190 °C, and keep warm for 10 min to form Nd-doped InP crystal nuclei, obtaining a solution containing Nd-doped InP crystal nucleus products.

[0094] 4) Preparation of S precursor solution:

[0095] Use 3 mL of DDT as the S source to prepare the S precursor solution for standby.

[0096] 5) Preparation of Nd-doped core-shell structure InPQDs:

[0097] Heat the solution containing Nd-doped InP crystal nucleus products in step 3) to 220 °C, and quickly inject the S precursor solution prepared in step 4) at 220 °C, and keep warm for 110 min to form Nd-doped core-shell structure InPQDs, obtaining a solution containing Nd-doped core-shell structure InPQDs products.

[0098] 6) The separation and purification of Nd-doped core-shell structure InPQDs are the same as in Example 1.

[0099] Example 5: This example provides a rare earth ion-doped indium phosphide quantum dot, which is prepared by the following steps.

[0100] 1) Preparation of In precursor mixed solution:

[0101] Add 7 mL of OLA, 3 mL of ODE, 0.4 mmol of InCl, 0.4 mmol of Nd(acac)3, and 0.4 mmol of ZnI2 into a three-necked flask; heat the mixed solution to 100 °C, and introduce N2 to remove water and oxygen for more than 30 min, then quickly stir until the raw materials are completely dissolved to obtain a clear In precursor mixed solution, keep the solution at 100 °C for standby.

[0102] 2) Preparation of P precursor solution:

[0103] Using 0.5 mL of (DMA)3P as the P source, prepare the P precursor solution for standby.

[0104] 3) Preparation of Nd-doped InP crystal nuclei:

[0105] Heat the In precursor mixed solution described in step 1) to 200 °C. At 200 °C, quickly inject the P precursor solution prepared in step 2), keep warm for 5 min to form Nd-doped InP crystal nuclei, and obtain a solution containing the product of Nd-doped InP crystal nuclei.

[0106] 4) Preparation of S precursor solution:

[0107] Using 3 mL of DDT as the S source, prepare the S precursor solution for standby.

[0108] 5) Preparation of Nd-doped core-shell structured InP QDs:

[0109] Heat the solution containing the product of Nd-doped InP crystal nuclei in step 3) to 240 °C. At 240 °C, quickly inject the S precursor solution prepared in step 4), keep warm for 90 min to form Nd-doped core-shell structured InP QDs, and obtain a solution containing the product of Nd-doped core-shell structured InP QDs.

[0110] 6) The separation and purification of Nd-doped core-shell structured InP QDs are the same as in Example 1.

[0111] Example 6: This example provides a rare earth ion-doped indium phosphide quantum dot, which is prepared by the following steps.

[0112] 1) Preparation of In precursor mixed solution:

[0113] Add 5 mL of OLA, 5 mL of ODE, 0.4 mmol of InI3, 0.6 mmol of Nd(acac)3, and 0.6 mmol of ZnBr2 into a three-necked flask; heat the mixed solution to 110 °C, and introduce N2 to remove water and oxygen for more than 30 min, then quickly stir until the raw materials are completely dissolved to obtain a clear In precursor mixed solution, keep the solution at 110 °C for standby.

[0114] 2) Preparation of P precursor solution:

[0115] Using 0.4 mL of (DMA)3P as the P source, prepare the P precursor solution for standby.

[0116] 3) Preparation of Nd-doped InP crystal nuclei:

[0117] Heat the In precursor mixed solution described in step 1) to 210 °C. At the temperature of 210 °C, quickly inject the P precursor solution prepared in step 2), keep warm for 8 min to form Nd-doped InP crystal nuclei, and obtain a solution containing the product of Nd-doped InP crystal nuclei.

[0118] 4) Preparation of S precursor solution:

[0119] Using 3 mL of DDT as the S source, prepare the S precursor solution for standby.

[0120] 5) Preparation of Nd-doped core-shell structure InP QDs:

[0121] Heat the solution containing the product of Nd-doped InP crystal nuclei in step 3) to 260 °C. At the temperature of 260 °C, quickly inject the S precursor solution prepared in step 4), keep warm for 130 min to form Nd-doped core-shell structure InP QDs, and obtain a solution containing the product of Nd-doped core-shell structure InP QDs.

[0122] 6) The separation and purification of Nd-doped core-shell structure InP QDs are the same as those in Example 1.

[0123] Example 7: This example provides a rare earth ion-doped indium phosphide quantum dot, which is prepared by the following steps.

[0124] 1) Preparation of In precursor mixed solution:

[0125] Add 3 mL of OLA, 7 mL of ODE, 0.4 mmol of InBr3, 0.6 mmol of Nd(acac)3, and 1.1 mmol of ZnBr2 into a three-necked flask; heat the mixed solution to 120 °C, and introduce N2 to remove water and oxygen for more than 30 min, then quickly stir until the raw materials are completely dissolved to obtain a clear In precursor mixed solution, and keep the solution at 120 °C for standby.

[0126] 2) Preparation of P precursor solution:

[0127] Using 0.5 mL of (DMA)3P as the P source, prepare the P precursor solution for standby.

[0128] 3) Preparation of Nd-doped InP crystal nuclei:

[0129] Heat the In precursor mixed solution to 220 °C. At 220 °C, quickly inject the P precursor solution prepared in step 2), keep the temperature for 12 min to form Nd-doped InP crystal nuclei, and obtain a solution containing the product of Nd-doped InP crystal nuclei.

[0130] 4) Preparation of S precursor solution:

[0131] Use 3 mL of DDT as the S source to prepare the S precursor solution for standby.

[0132] 5) Preparation of Nd-doped core-shell structured InPQDs:

[0133] Heat the solution containing the product of Nd-doped InP crystal nuclei in step 3) to 280 °C. At 280 °C, quickly inject the S precursor solution prepared in step 4), keep the temperature for 80 min to form Nd-doped core-shell structured InPQDs, and obtain a solution containing the product of Nd-doped core-shell structured InPQDs.

[0134] 6) The separation and purification of Nd-doped core-shell structured InPQDs are the same as those in Example 1.

[0135] Example 8: This example provides a rare earth ion-doped indium phosphide quantum dot, which is prepared by the following steps.

[0136] 1) Preparation of In precursor mixed solution:

[0137] Add 5.5 mL of OLA, 4.5 mL of ODE, 0.4 mmol of InI3, 1.4 mmol of Nd(acac)3, and 2.8 mmol of ZnI2 into a three-necked flask; heat the mixed solution to 140 °C, and introduce N2 to remove water and oxygen for more than 30 min, then quickly stir until the raw materials are completely dissolved to obtain a clear In precursor mixed solution, and keep the solution at 140 °C for standby.

[0138] 2) Preparation of P precursor solution:

[0139] Use 0.6 mL of (DMA)3P as the P source to prepare the P precursor solution for standby.

[0140] 3) Preparation of Nd-doped InP crystal nuclei:

[0141] Heat the In precursor mixed solution described in step 1) to 230 °C. At 230 °C, quickly inject the P precursor solution prepared in step 2), keep the temperature for 15 min to form Nd-doped InP crystal nuclei, and obtain a solution containing the product of Nd-doped InP crystal nuclei.

[0142] 4) Preparation of S precursor solution:

[0143] Use 3 mL of DDT as the S source to prepare a S precursor solution for later use.

[0144] 5) Preparation of Nd-doped core-shell InPQDs:

[0145] The solution containing the Nd-doped InP crystal core product of step 3) is heated to 300° C. At 300° C., the S precursor solution prepared in step 4) is quickly injected and kept warm for 150 minutes to form Nd-doped core-shell structure InPQDs, thereby obtaining a solution containing Nd-doped core-shell structure InPQDs products.

[0146] 6) The separation and purification of Nd-doped core-shell InPQDs is the same as in Example 1.

[0147] The fluorescence quantum yield and fluorescence emission peak of Examples 1 to 8 of the present application were detected, and the Chinese invention patent with publication number CN113956879A was used as a comparative example. The specific detection results are shown in Table 1 below.

[0148] Table 1 Test results

[0149] PLQY Fluorescence emission peak Example 1 95% 488 nm Example 2 96% 481 nm Example 3 95% 470 nm Example 4 93% 520 nm Example 5 90% 513 nm Example 6 94% 504 nm Example 7 91% 493 nm Example 8 93% 476 nm Comparative example 78% 458 nm

[0150] It can be seen from the data in Table 1 that the rare earth ion-doped blue light indium phosphide quantum dots prepared in the present application have a fluorescence quantum yield of more than 90%, and by adjusting the amount of neodymium element added and the amount of zinc element added, the emission wavelength can be tuned in the range of 470~520nm, and various performances are significantly better than the blue light indium phosphide quantum dots in the prior art.

[0151] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A rare-earth doped indium phosphide blue light quantum dot, characterized in that, The indium phosphide blue light quantum dots adopt a core-shell structure formed on the basis of quantum dots, including an indium phosphide crystal nucleus doped with neodymium element and an external zinc sulfide shell layer; In the indium phosphide blue light quantum dots, the molar ratio of indium element to neodymium element is 1:0.1~4; In the indium phosphide blue light quantum dots, the molar ratio of indium element to zinc element is 1:n, where 0 < n ≤ 7; The preparation method of the rare earth doped indium phosphide blue light quantum dots includes the following steps: S1. At the first temperature, an indium precursor, rare earth neodymium and a zinc precursor are added to a non-coordinating solvent, oxygen in the solution is excluded, and after mixing evenly, an indium precursor mixed solution is prepared and kept at the first temperature for standby; S2. At the second temperature, a phosphorus source is injected into the indium precursor mixed solution prepared in step S1 and kept for more than 5 minutes to obtain an indium phosphide mixed solution; S3. A sulfur precursor is injected into the indium phosphide mixed solution prepared in step S2, and the temperature is raised to the third temperature to react to form indium phosphide quantum dots with a core-shell structure. After separation and purification, rare earth doped indium phosphide blue light quantum dots are obtained; The first temperature is 80~140 °C; the second temperature is 180~230 °C; the third temperature is 200~300 °C.

2. The rare earth-doped indium phosphide blue light quantum dots according to claim 1, characterized in that, In step S1, the solvent adopts a mixed solution of oleylamine and octadecene.

3. The rare earth-doped indium phosphide blue light quantum dot according to claim 1, wherein In step S1, the indium precursor is selected from one or more of indium chloride, indium bromide and indium iodide; the rare earth neodymium adopts neodymium acetylacetonate; the zinc precursor is selected from one or more of zinc chloride, zinc bromide and zinc iodide.

4. The rare earth-doped indium phosphide blue light quantum dot according to claim 1, wherein, In step S2, the phosphorus source adopts tris(dimethylamino)phosphine; the phosphorus source is added at a rate of more than 1 mL of phosphorus source per 1 mmol of indium precursor.

5. The rare earth-doped indium phosphide blue light quantum dot according to claim 1, characterized in that, In step S3, the sulfur precursor adopts dodecyl mercaptan.

6. The rare earth-doped indium phosphide blue light quantum dots according to any one of claims 1-5, characterized in that, Steps S1 to S3 are all completed under the protection of a nitrogen atmosphere.

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