Synthesis method of green InP quantum dot with narrow half width and high luminous efficiency

Abstract

The invention relates to the technical field of inorganic semiconductor quantum dots, in particular to a synthesis method of a green InP quantum dot with narrow half-width and high luminous efficiency, and gallium treatment is performed on an InP core, so that phosphine bonds on the surface of the core can be effectively reduced, and the luminous efficiency of the quantum dot is improved. Manganese doping of the middle shell layer is carried out on the InP core after gallium treatment, the half width of the quantum dot can be effectively reduced, and the prepared Ga-InP / ZnSe (Mn) S / ZnS quantum dot has small half width and ultrahigh luminous efficiency and stability. Therefore, the problem that the luminous efficiency of the quantum dot is relatively low due to the fact that a large number of phosphine bonds exist on the surface of the original InP quantum dot is solved.

Description

Technical Field

[0001] The invention relates to the technical field of inorganic semiconductor quantum dots, and in particular to a method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency. Background Art

[0002] Colloidal quantum dots (QDs) are an outstanding nanoscale semiconductor light-emitting material. The size of QDs is about 2 to 10 nm. Due to their adjustable size, they can be tuned to emit light in the entire visible light range. Their luminous intensity is closely related to their size. Due to their wide color gamut, high luminescent purity and narrow emission bandwidth, they can be widely used in light-emitting diodes (LEDs), photodetectors, bioimaging and solar cells.

[0003] However, there are often a large number of phosphine empty bonds on the surface of the original InP quantum dots, and these defects will seriously affect the luminescence efficiency of the quantum dots. In addition, the half-width of quantum dots (i.e. the width of the luminescence spectrum) is also an important indicator to measure its performance. A narrower half-width means higher luminescence purity and better color saturation. Summary of the invention

[0004] The purpose of the present invention is to provide a method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency, aiming to solve the problem that a large number of phosphine vacant bonds often exist on the surface of original InP quantum dots, resulting in low luminous efficiency of quantum dots.

[0005] To achieve the above object, the present invention provides a method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency, comprising the following steps:

[0006] reacting a mixed precursor solution of indium iodide, zinc chloride and oleylamine with a mixed solution of aminophosphine and tri-n-octylphosphine to obtain an InP core solution;

[0007] The InP core solution is added to a mixed solution of zinc chloride, oleylamine and octadecene, and a mixed solution of potassium iodide and oleylamine is injected, and then a selenium precursor solution, a zinc precursor solution and a sulfur precursor solution are added in sequence for reaction to obtain Ga-InP / ZnSeS thin-shell quantum dots;

[0008] A mixed solution of manganese chloride and oleylamine is added to Ga-InP / ZnSeS thin-shell quantum dots, and a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution are added in sequence to react to obtain Ga-InP / ZnSe(Mn)S quantum dots;

[0009] Selenium precursor solution, zinc precursor solution and sulfur precursor solution are sequentially added to Ga-InP / ZnSe(Mn)S quantum dots for a primary reaction, and selenium precursor solution, zinc precursor solution and sulfur precursor solution are added again for a secondary reaction to obtain Ga-InP / ZnSe(Mn)S thick shell quantum dots;

[0010] A mixed solution of zinc acetate, octadecene and oleic acid was added to Ga-InP / ZnSe(Mn)S thick-shell quantum dots, and n-dodecyl mercaptan was added again for a secondary reaction to obtain Ga-InP / ZnSe(Mn)S / ZnS quantum dots.

[0011] Wherein, in “reacting a mixed precursor solution of indium iodide, zinc chloride and oleylamine with a mixed solution of aminophosphine and tri-n-octylphosphine to obtain an InP core solution”, the reaction temperature is 180°C.

[0012] Among them, in "adding the InP core solution to a mixed solution of zinc chloride, oleylamine and octadecene, injecting a mixed solution of potassium iodide and oleylamine, and then adding a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution in sequence to react to obtain Ga-InP / ZnSeS thin-shell quantum dots", the reaction temperature is 270°C. Among them, in "adding a mixed solution of manganese chloride and oleylamine to Ga-InP / ZnSeS thin-shell quantum dots, and then adding a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution in sequence to react to obtain Ga-InP / ZnSe(Mn)S quantum dots", the reaction temperature is 280°C.

[0013] Among them, in "adding selenium precursor solution, zinc precursor solution and sulfur precursor solution to Ga-InP / ZnSe(Mn)S quantum dots in sequence, conducting a primary reaction, adding selenium precursor solution, zinc precursor solution and sulfur precursor solution again, conducting a secondary reaction to obtain Ga-InP / ZnSe(Mn)S thick-shell quantum dots", the temperature of the primary reaction is 290°C, and the temperature of the secondary reaction is 300°C.

[0014] Among them, in "adding a mixed solution of zinc acetate, octadecene and oleic acid to Ga-InP / ZnSe(Mn)S thick-shell quantum dots, and adding n-dodecanethiol again for a secondary reaction to obtain Ga-InP / ZnSe(Mn)S / ZnS quantum dots", the temperature of the primary reaction is 220°C, and the temperature of the secondary reaction is 190°C.

[0015] The invention discloses a method for synthesizing green InP quantum dots with narrow half width and high luminous efficiency, comprising the following steps: reacting a mixed precursor solution of indium iodide, zinc chloride and oleylamine with a mixed solution of aminophosphine and tri-n-octylphosphine to obtain an InP core solution; adding the InP core solution to a mixed solution of zinc chloride, oleylamine and octadecene, injecting a mixed solution of potassium iodide and oleylamine, and then sequentially adding a selenium precursor solution, a zinc precursor solution and a sulfur precursor solution to react to obtain Ga-InP / ZnSeS thin-shell quantum dots; adding a mixed solution of manganese chloride and oleylamine to the Ga-InP / ZnSeS thin-shell quantum dots, and sequentially adding a selenium precursor solution, a zinc precursor solution and a sulfur precursor solution to react to obtain Ga-InP / ZnSeS thin-shell quantum dots. Liquid, sulfur precursor solution after reaction, to obtain Ga-InP / ZnSe(Mn)S quantum dots; in the Ga-InP / ZnSe(Mn)S quantum dots, a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution are sequentially added to carry out a primary reaction, and a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution are added again to carry out a secondary reaction to obtain Ga-InP / ZnSe(Mn)S thick shell quantum dots; a mixed solution of zinc acetate, octadecene, and oleic acid is added to the Ga-InP / ZnSe(Mn)S thick shell quantum dots, and n-dodecyl mercaptan is added again to carry out a secondary reaction to obtain Ga-InP / ZnSe(Mn)S / ZnS quantum dots. The gallium treatment of the InP core by the present invention can effectively reduce the phosphine empty bonds on the core surface, thereby improving the luminescence efficiency of the quantum dots. Manganese doping of the intermediate shell of the gallium-treated InP core can effectively reduce the half-width of the quantum dots. The prepared Ga-InP / ZnSe(Mn)S / ZnS quantum dots have a smaller half-width, ultra-high luminescence efficiency and stability. This solves the problem that the original InP quantum dots often have a large number of phosphine empty bonds on the surface, resulting in low luminescence efficiency of the quantum dots. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 This is a transmission electron microscopy image of the InP / ZnSeS / ZnS core-shell quantum dots prepared in Example 1.

[0018] Figure 2 This is the absorption and fluorescence spectra of the InP / ZnSeS / ZnS core-shell quantum dots prepared in Example 1.

[0019] Figure 3These are optical images of the InP / ZnSeS / ZnS core-shell quantum dots prepared in Example 1 under sunlight and ultraviolet light.

[0020] Figure 4 This is the fluorescence lifetime diagram of the Ga-InP / ZnSeS / ZnS core-shell quantum dots prepared in Example 1.

[0021] Figure 5 This is the absorption and fluorescence spectra of the Ga-InP / ZnSeS / ZnS core-shell quantum dots prepared in Example 2.

[0022] Figure 6 This is the fluorescence lifetime diagram of the Ga-InP / ZnSe / ZnS core-shell quantum dots prepared in Example 2.

[0023] Figure 7 This is a transmission electron microscopy image of the InP / Zn(Mn)Se / ZnS core-shell quantum dots prepared in Example 3.

[0024] Figure 8 The absorption and fluorescence spectra of InP / Zn(Mn)Se / ZnS core-shell quantum dots prepared in Example 3.

[0025] Fig. 9 This is the fluorescence lifetime diagram of InP / Zn(Mn)Se / ZnS core-shell quantum dots prepared in Example 3.

[0026] Fig.10 This is a transmission electron microscopy image of the Ga-InP / Zn(Mn)SeS / ZnS core-shell quantum dots prepared in Example 4.

[0027] Fig.11 The absorption and fluorescence spectra of Ga-InP / Zn(Mn)SeS / ZnS core-shell quantum dots prepared in Example 4 are shown.

[0028] Fig.12 This is the fluorescence lifetime diagram of Ga-InP / Zn(Mn)SeS / ZnS core-shell quantum dots prepared in Example 4.

[0029] Fig.13 These are optical images of the InP / ZnSe / ZnS core-shell quantum dots prepared in Example 4 under sunlight and ultraviolet light.

[0030] Fig.14 The present invention provides a flow chart of a method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency. DETAILED DESCRIPTION

[0031] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0032] See also Figures 1 to 5 The present invention provides a method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency, comprising the following steps:

[0033] S1: reacting a mixed precursor solution of indium iodide, zinc chloride and oleylamine with a mixed solution of aminophosphine and tri-n-octylphosphine to obtain an InP core solution;

[0034] The temperature of the reaction was 180°C.

[0035] Specifically, the reaction temperature is 180° C. At this temperature, the mixed precursor solution of indium iodide, zinc chloride and oleylamine reacts chemically with the mixed solution of aminophosphine and tri-n-octylphosphine to generate an InP core solution. As a ligand, oleylamine can form coordination bonds with atoms on the surface of the InP core, stabilize the structure of the InP core, and prevent it from agglomerating or decomposing in subsequent reactions.

[0036] Accurately weigh the required chemical raw materials and dissolve them in an appropriate solvent to form a uniformly mixed precursor solution; heat and stir the two mixed solutions at a set temperature of 180°C to allow the reaction to proceed fully until an InP core solution is generated.

[0037] S2: adding the InP core solution to a mixed solution of zinc chloride, oleylamine and octadecene, injecting a mixed solution of potassium iodide and oleylamine, and then sequentially adding a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution to react to obtain Ga-InP / ZnSeS thin-shell quantum dots;

[0038] The temperature of the reaction was 270°C.

[0039] Specifically, the reaction temperature is 270°C. At this temperature, the InP core solution is mixed with a mixed solution of zinc chloride, oleylamine and octadecene, and then a mixed solution of potassium iodide and oleylamine is injected, providing the necessary chemical environment for the subsequent shell growth. Then, a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution are added in sequence. The selenium, zinc, and sulfur elements in these precursor solutions react with the InP core surface at high temperature to form Ga-InP / ZnSeS thin-shell quantum dots.

[0040] Add a mixed solution of zinc chloride, oleylamine and octadecene to the InP core solution and stir evenly;

[0041] Rapidly inject a mixed solution of potassium iodide and oleylamine to promote the incorporation of gallium on the surface of the InP core;

[0042] Selenium precursor solution, zinc precursor solution and sulfur precursor solution are added in sequence, and the reaction temperature and time are controlled to form Ga-InP / ZnSeS thin-shell quantum dots.

[0043] S3: adding a mixed solution of manganese chloride and oleylamine to Ga-InP / ZnSeS thin-shell quantum dots, and then sequentially adding a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution to react to obtain Ga-InP / ZnSe(Mn)S quantum dots;

[0044] The temperature of the reaction was 280°C.

[0045] Specifically, the reaction temperature is 280° C. At this temperature, after the mixed solution of manganese chloride and oleylamine is mixed with the Ga-InP / ZnSeS thin-shell quantum dots, the manganese ions in the manganese chloride can enter the ZnSeS shell layer under the coordination of oleylamine to achieve manganese doping. Subsequently, a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution are added in sequence, and the selenium, zinc, and sulfur elements in these precursor solutions react with the ZnSeS shell layer doped with manganese to form Ga-InP / ZnSe(Mn)S quantum dots.

[0046] A mixed solution of manganese chloride and oleylamine was added to Ga-InP / ZnSeS thin-shell quantum dots to achieve manganese doping.

[0047] Selenium precursor solution, zinc precursor solution and sulfur precursor solution are added in sequence, and the reaction temperature and time are maintained to form manganese-doped Ga-InP / ZnSe(Mn)S quantum dots.

[0048] S4: adding a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution to the Ga-InP / ZnSe(Mn)S quantum dots in sequence, and then performing a primary reaction; and then adding a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution again, and then performing a secondary reaction, to obtain Ga-InP / ZnSe(Mn)S thick-shell quantum dots;

[0049] The temperature of the primary reaction is 290°C, and the temperature of the secondary reaction is 300°C.

[0050] Specifically, the temperature of the first reaction is 290°C, and the temperature of the second reaction is 300°C. When the first reaction is carried out at 290°C, selenium, zinc, and sulfur elements in the selenium precursor solution, zinc precursor solution, and sulfur precursor solution react with the surface of Ga-InP / ZnSe(Mn)S quantum dots to begin to form a thick shell layer. Subsequently, the second reaction is carried out at 300°C to further promote the growth of the thick shell layer, making it more uniform and dense.

[0051] Adding selenium precursor solution, zinc precursor solution and sulfur precursor solution to Ga-InP / ZnSe(Mn)S quantum dots multiple times to perform multiple shell growth;

[0052] The temperature and time of each reaction are controlled to ensure uniform growth and thickness increase of the shell.

[0053] S5: Add a mixed solution of zinc acetate, octadecene and oleic acid to Ga-InP / ZnSe(Mn)S thick-shell quantum dots, and then add n-dodecyl mercaptan for a secondary reaction to obtain Ga-InP / ZnSe(Mn)S / ZnS quantum dots.

[0054] The temperature of the primary reaction is 220°C, and the temperature of the secondary reaction is 190°C.

[0055] Specifically, the temperature of the first reaction is 220°C, and the temperature of the second reaction is 190°C. When the first reaction is carried out at 220°C, the zinc and sulfur elements in the mixed solution of zinc acetate, octadecene and oleic acid react with the surface of Ga-InP / ZnSe(Mn)S thick-shell quantum dots to begin to form a ZnS outer shell layer. Subsequently, the second reaction is carried out at 190°C, and the sulfur element in n-dodecyl mercaptan further reacts with the zinc atoms on the surface of the quantum dots, making the ZnS outer shell layer more uniform and dense.

[0056] A mixed solution of zinc acetate, octadecene and oleic acid was added to Ga-InP / ZnSe(Mn)S thick-shell quantum dots to perform the initial growth of the outer shell layer.

[0057] n-Dodecanethiol was added and the final reaction was completed at a relatively low temperature to form stable Ga-InP / ZnSe(Mn)S / ZnS quantum dots.

[0058] Example 1

[0059] A method for synthesizing InP / ZnSeS / ZnS core-shell quantum dots, comprising the following steps:

[0060] InP nucleation

[0061] A mixed precursor solution of indium iodide, zinc chloride and oleylamine and a mixed solution of aminophosphine and tri-n-octylphosphine are reacted at 180° C. to obtain an InP core solution.

[0062] Intermediate shell coating

[0063] The above InP core solution is added to a mixed solution of zinc chloride, oleylamine and octadecene, and a selenium precursor solution, a zinc precursor solution and a sulfur precursor solution are added in sequence, and reacted at 270°C to obtain InP / ZnSeS thin-shell quantum dots. Selenium precursor solution, zinc precursor solution and sulfur precursor solution are added again to react at 280°C, and then selenium precursor solution, zinc precursor solution and sulfur precursor solution are added in sequence to react at 290°C, and selenium precursor solution, zinc precursor solution and sulfur precursor solution are added again to react at 300°C to obtain InP / ZnSe thick-shell quantum dots.

[0064] Shell growth

[0065] A mixed solution of zinc acetate, octadecene and oleic acid was added to the above quantum dot system and reacted at 220° C. Dodecanethiol was added again and reacted at 190° C. to obtain InP / ZnSeS / ZnS quantum dots.

[0066] Example 2

[0067] A method for synthesizing Ga-InP / ZnSeS / ZnS core-shell quantum dots comprises the following steps:

[0068] Gallium treatment and intermediate shell coating

[0069] As in Example 1, InP nucleation was first performed, and the above InP core solution was added to a mixed solution of zinc chloride, oleylamine and octadecene, and then a mixed solution of potassium iodide and oleylamine was quickly injected, and then a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution were added in sequence, and reacted at 270°C to obtain Ga-InP / ZnSeS thin-shell quantum dots. In the same way as in Example 1, multiple steps of inner shell growth and outer shell growth were performed to finally obtain Ga-InP / ZnSeS / ZnS quantum dots.

[0070] Example 3

[0071] A method for synthesizing InP / Zn(Mn)SeS / ZnS core-shell quantum dots comprises the following steps:

[0072] Mn intershell doping

[0073] Same as Example 1, InP nucleation is performed, and then the first growth of the inner shell ZnSeS is performed.

[0074] Example 4

[0075] 1) Gallium treatment

[0076] As in Example 1, InP nucleation is first performed, and the above InP core solution is added to a mixed solution of zinc chloride, oleylamine and octadecene, and then a mixed solution of potassium iodide and oleylamine is quickly injected, and then a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution are added in sequence, and the reaction is carried out at 270°C to obtain Ga-InP / ZnSeS thin-shell quantum dots.

[0077] Mn intershell doping

[0078] A mixed solution of manganese chloride and oleylamine was added to the Ga-InP / ZnSeS reaction solution obtained above, and a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution were added in sequence to react at 280°C to obtain Ga-InP / ZnSe(Mn)S quantum dots. The multi-step growth of the inner shell layer and the growth of the outer shell layer were performed in the same manner as in Example 1 to finally obtain Ga-InP / Zn(Mn)SeS / ZnS quantum dots.

[0079] The present invention provides a method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency, which has the following beneficial effects:

[0080] 1) The present invention provides a method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency. Gallium treatment of the InP core can effectively reduce the phosphine vacancy bonds on the core surface, thereby improving the luminous efficiency of the quantum dots.

[0081] 2) The present invention provides a method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency. Manganese doping of the intermediate shell of the InP core after gallium treatment can effectively reduce the half-width of the quantum dots. The prepared Ga-InP / ZnSe(Mn)S / ZnS quantum dots have a smaller half-width, ultra-high luminous efficiency and stability.

[0082] The above disclosure is only a preferred embodiment of a method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency of the present invention. Of course, this cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiments and equivalent changes made according to the claims of the present invention still fall within the scope of the invention.

Claims

1. A method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency, characterized in that: The following steps are involved: reacting a mixed precursor solution of indium iodide, zinc chloride and oleylamine with a mixed solution of aminophosphine and tri-n-octylphosphine to obtain an InP core solution; The InP core solution is added to a mixed solution of zinc chloride, oleylamine and octadecene, and a mixed solution of potassium iodide and oleylamine is injected, and then a selenium precursor solution, a zinc precursor solution and a sulfur precursor solution are added in sequence for reaction to obtain Ga-InP / ZnSeS thin-shell quantum dots; A mixed solution of manganese chloride and oleylamine is added to Ga-InP / ZnSeS thin-shell quantum dots, and a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution are added in sequence to react to obtain Ga-InP / ZnSe(Mn)S quantum dots; Selenium precursor solution, zinc precursor solution and sulfur precursor solution are sequentially added to Ga-InP / ZnSe(Mn)S quantum dots for a primary reaction, and selenium precursor solution, zinc precursor solution and sulfur precursor solution are added again for a secondary reaction to obtain Ga-InP / ZnSe(Mn)S thick shell quantum dots; A mixed solution of zinc acetate, octadecene and oleic acid was added to Ga-InP / ZnSe(Mn)S thick-shell quantum dots, and n-dodecyl mercaptan was added again for a secondary reaction to obtain Ga-InP / ZnSe(Mn)S / ZnS quantum dots.

2. The method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency as claimed in claim 1, characterized in that: In "reacting a mixed precursor solution of indium iodide, zinc chloride and oleylamine with a mixed solution of aminophosphine and tri-n-octylphosphine to obtain an InP core solution", the reaction temperature is 180°C.

3. The method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency as claimed in claim 1, characterized in that: In "adding the InP core solution to a mixed solution of zinc chloride, oleylamine and octadecene, injecting a mixed solution of potassium iodide and oleylamine, and then sequentially adding a selenium precursor solution, a zinc precursor solution and a sulfur precursor solution to react to obtain Ga-InP / ZnSeS thin-shell quantum dots", the reaction temperature is 270°C.

4. The method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency as claimed in claim 1, characterized in that: In "adding a mixed solution of manganese chloride and oleylamine to Ga-InP / ZnSeS thin-shell quantum dots, and sequentially adding a selenium precursor solution, a zinc precursor solution, and a sulfur precursor solution to react to obtain Ga-InP / ZnSe(Mn)S quantum dots", the reaction temperature is 280°C.

5. The method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency as claimed in claim 1, characterized in that: In "adding selenium precursor solution, zinc precursor solution and sulfur precursor solution to Ga-InP / ZnSe(Mn)S quantum dots in sequence, conducting a primary reaction, adding selenium precursor solution, zinc precursor solution and sulfur precursor solution again, conducting a secondary reaction to obtain Ga-InP / ZnSe(Mn)S thick-shell quantum dots", the temperature of the primary reaction is 290°C, and the temperature of the secondary reaction is 300°C.

6. The method for synthesizing green InP quantum dots with narrow half-width and high luminous efficiency as claimed in claim 1, characterized in that: In "a mixed solution of zinc acetate, octadecene and oleic acid is added to Ga-InP / ZnSe(Mn)S thick-shell quantum dots, and n-dodecanethiol is added again for a secondary reaction to obtain Ga-InP / ZnSe(Mn)S / ZnS quantum dots", the temperature of the primary reaction is 220°C, and the temperature of the secondary reaction is 190°C.

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