WO2020134260A1

WO2020134260A1 - Magnetic quantum dot and preparation method therefor, and ink cartridge

Info

Publication number: WO2020134260A1
Application number: PCT/CN2019/108621
Authority: WO
Inventors: 罗植天; 向超宇; 张滔; 朱佩
Original assignee: Tcl科技集团股份有限公司
Priority date: 2018-12-28
Filing date: 2019-09-27
Publication date: 2020-07-02
Also published as: CN111378326A; CN111378326B

Abstract

A magnetic quantum dot. The magnetic quantum dot comprises a magnetic nanoparticle core (10), a quantum dot layer (20) coating the outer surface of the magnetic nanoparticle core, and an organic shell layer (30) coating the outer surface of the quantum dot layer. A preparation method for magnetic quantum dots comprises: adding quantum dots and magnetic nanoparticles into a surfactant-containing aqueous solution to obtain a micellar solution in which quantum dot layers (20) coat magnetic nanoparticle cores (10); and then mixing the micellar solution with organic shell layer (30) materials to obtain magnetic quantum dots. Magnetic quantum dots are prepared into magnetic ink of different colors according to requirements and are mixed with common ink and injected into an ink cartridge. The ink cartridge comprises a body, a nozzle, and an electromagnetic field generator provided between the body and the nozzle. By controlling the strength of the electromagnetic field, the content of the magnetic ink in the jetted ink is controlled, and the components of the jetted ink are adjusted, improving the printing efficiency and the utilization rate of the ink cartridge.

Description

Magnetic quantum dot, preparation method thereof, and ink cartridge

Technical field

The present disclosure relates to the technical field of quantum dots, in particular to a magnetic quantum dot, a preparation method thereof, and an ink cartridge.

Background technique

Quantum dots are a special material that is limited to the order of nanometers in three dimensions. This significant quantum confinement effect makes quantum dots have many unique nano properties: continuously adjustable emission wavelength, narrow emission wavelength, Wide absorption spectrum, high luminous intensity, long fluorescence lifetime and good biocompatibility. These characteristics make quantum dots have broad application prospects in the fields of biomarkers, flat panel displays, solid-state lighting, photovoltaic solar energy and other fields.

At present, in the display field, each functional layer of the light-emitting element can be prepared by inkjet printing, evaporation and other methods. The inkjet printing method has become a fast deposition rate, good uniformity, low equipment investment, and high material utilization. One of the common methods for preparing quantum dot light-emitting diodes. In the process of inkjet printing, the quantum dots in the ink used usually do not have some special properties, such as magnetism, and cannot be controlled by electromagnetic fields. When the ink is installed in the ink cartridge, it is necessary to adjust and compare its composition ratio. difficult.

Therefore, the existing technology needs to be improved and developed.

Summary of the invention

In view of the above shortcomings of the prior art, the purpose of the present disclosure is to provide a magnetic quantum dot, its preparation method, and an ink cartridge, aiming to solve the problem that the ink in the ink cartridge does not have Magnetic, the problem of ink composition is not easy to adjust.

The technical solutions of the present disclosure are as follows:

A magnetic quantum dot, wherein the magnetic quantum dot includes a magnetic nanoparticle core, a quantum dot layer coated on the outer surface of the magnetic nanoparticle core, and an organic shell layer coated on the outer surface of the quantum dot layer .

The magnetic quantum dots, wherein the surfaces of the quantum dots constituting the quantum dot layer and the magnetic nanoparticles constituting the magnetic nanoparticle core are modified with organic ligands, the magnetic nanoparticle core and the quantum dots The layers are combined by the organic ligand.

The magnetic quantum dot, wherein the surface of the quantum dot layer facing the magnetic nanoparticle core is modified with organic ligands, and the surface of the quantum dot layer facing away from the magnetic nanoparticle core is modified with organic ligands, so The surface of the quantum dot layer facing away from the magnetic nanoparticle core is also modified with a surfactant, and the hydrophobic end of the surfactant is combined with a corresponding organic ligand.

The magnetic quantum dot, wherein the surface of the quantum dot layer facing away from the magnetic nanoparticle core is modified with the organic ligand, and the surface of the quantum dot layer facing away from the magnetic nanoparticle core is also modified with surface activity Agent, the hydrophobic end of the surfactant binds to the corresponding organic ligand.

In the magnetic quantum dot, the organic shell material is one of polyvinylpyrrolidone, polyvinyl alcohol and polyethylene glycol.

In the magnetic quantum dot, the organic ligand is a mercapto group-containing organic ligand.

The magnetic quantum dot, wherein the magnetic nanoparticle core material is selected from at least one of Fe ₃ O ₄ , γ-Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ and MnFe ₂ O ₄ .

In the magnetic quantum dot, the hydrophilic end of the surfactant is combined with the organic shell layer on the outer surface of the quantum dot layer.

The magnetic quantum dots, wherein the surfactant in the surfactant-containing aqueous solution is selected from tetradecyl ammonium bromide, cetyl trimethyl ammonium bromide and dodecyl trimethyl bromide One of ammonium chloride.

In the magnetic quantum dot, the organic ligand containing a mercapto group is selected from one or more of monothiol, dithiol, mercaptoalcohol, mercaptoamine and mercapto acid.

A preparation method of magnetic quantum dots, which comprises the steps of:

Add quantum dots and magnetic nanoparticles to an aqueous solution containing a surfactant, and mix the quantum dots to coat the outer surface of the magnetic nanoparticle core to obtain a micellar solution of the quantum dot layer covering the magnetic nanoparticle core;

The micelle solution coated with the magnetic nanoparticle core by the quantum dot layer is mixed with the organic shell material to coat the outer surface of the quantum dot layer with the organic shell material to obtain the magnetic quantum dot.

The preparation method of the magnetic quantum dots, wherein the surfactant in the surfactant-containing aqueous solution is selected from tetradecyl ammonium bromide, cetyl trimethyl ammonium bromide and dodecyl trimethyl One of the base ammonium bromide.

The method for preparing magnetic quantum dots, wherein in the step, quantum dots and magnetic nanoparticles are added to an aqueous solution containing a surfactant, and the quantum dots are coated on the outer surface of the magnetic nanoparticle core to obtain a quantum dot layer The micellar solution coating the magnetic nanoparticle core specifically includes:

Dissolve quantum dots and magnetic nanoparticles in an organic solvent to obtain a mixed solution;

After the mixed solution is added to the aqueous solution containing the surfactant, relative movement occurs between the mixed solution and the aqueous solution;

During the relative movement, an inert gas is introduced to remove the organic solvent, so that the magnetic nanoparticle cores are agglomerated, and part of the surfactant on the surface of the quantum dots falls off to expose the organic ligands. The ligand forms a solvophobic effect to obtain a micelle solution in which the quantum dot layer covers the magnetic nanoparticle core.

The method for preparing magnetic quantum dots, wherein in the step, the micelle solution coated with the magnetic nanoparticle core by the quantum dot layer is mixed with an organic shell material to coat the quantum The outer surface of the dot layer to obtain the magnetic quantum dot specifically includes:

The micelle solution coated with the magnetic nanoparticle core of the quantum dot layer is added to the solution containing the shell layer material, and the organic shell layer material is coated on the outer surface of the quantum dot layer to obtain the magnetic quantum dot.

The method for preparing magnetic quantum dots, wherein the magnetic nanoparticle material is selected from at least one of Fe ₃ O ₄ , γ-Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ O ₄ and MnFe ₂ O ₄ .

An ink cartridge includes an ink cartridge body and a nozzle, wherein an electromagnetic field generator is further provided between the ink cartridge body and the nozzle; the ink cartridge body contains ink, and the ink contains magnetic quantum dots and nonmagnetic quantum Dots; the magnetic quantum dots are produced by the above-mentioned magnetic quantum dots or the preparation method of the above magnetic quantum dots.

Beneficial effect: The quantum dots provided by the present disclosure are magnetically doped to have a certain magnetic property, and then the magnetic quantum dots are used in ink for inkjet printing, and the magnetic ink and the non-magnetic ink are injected In the same ink cartridge, by controlling the intensity of the electromagnetic field set at the nozzle of the ink cartridge, controlling the content of the magnetic ink in the ink, adjusting the composition of the ink, effectively improving the printing efficiency and the utilization rate of the ink cartridge.

BRIEF DESCRIPTION

FIG. 1 is a schematic structural diagram of a specific embodiment of a magnetic quantum dot of the present disclosure.

FIG. 2a is a schematic structural view of the organic ligands bound to the surface of quantum dots and magnetic nanoparticles during the preparation of magnetic quantum dots of the present disclosure.

2b is a schematic structural view of the quantum dots and magnetic nanoparticles modified by DTAB in the process of preparing magnetic quantum dots of the present disclosure.

2c is a schematic structural view of the process of forming QD-MNP-micelles by quantum dots and magnetic nanoparticles in the process of preparing magnetic quantum dots of the present disclosure through the solvophobic action.

FIG. 3 is a flowchart of a method for preparing magnetic quantum dots of the present disclosure.

4 is a schematic structural diagram of the ink cartridge of the present disclosure.

detailed description

The present disclosure provides a method for automatic backlight adjustment. In order to make the purposes, technical solutions, and effects of the present disclosure clearer and clearer, the present disclosure will be described in further detail below. It should be understood that the specific embodiments described herein are only used to explain the present disclosure and are not intended to limit the present disclosure.

The present disclosure provides a magnetic quantum dot. As shown in FIG. 1, the magnetic quantum dot includes a magnetic nanoparticle core 10 formed by magnetic agglomeration of a plurality of magnetic nanoparticles, and a quantum coated on the outer surface of the magnetic nanoparticle core The dot layer 20 is an organic shell layer 30 covering the outer surface of the quantum dot layer. Wherein, the surfaces of the quantum dots constituting the quantum dot layer and the magnetic nanoparticles constituting the magnetic nanoparticle core are modified with organic ligands, and the magnetic nanoparticle core and the quantum dot layer pass through the organic ligands Combine.

In the present disclosure, magnetic nanoparticles with organic ligands on the surface and quantum dots are mixed and added to an aqueous solution containing a surfactant. The selected magnetic nanoparticles will form magnetic nanoparticle cores due to magnetic agglomeration during stirring. The formed magnetic nanoparticle cores and quantum dots form micelles under the action of a solvent. A protective organic shell layer is coated on the outer layer of the micelle to obtain magnetic quantum dot ultra-nano particles. The existing ordinary quantum dots are magnetic, which gives them new functions.

In one or more embodiments, the quantum dots with organic ligands on the surface and the magnetic nanoparticles with organic ligands on the surface are modified with a surfactant, the modified quantum dots and the modified magnetic nanoparticles , Can be evenly dispersed in the aqueous solution, such as high-speed stirring or vibration, the modified quantum dots and the active agent on the surface of the modified magnetic nanoparticles are partially shed, the hydrophobic ligands on the surface of the quantum dots, and the surface of the magnetic nanoparticles The water-repellent ligand is exposed, so that the hydrophobic ligand on the surface of the magnetic nanoparticles and the hydrophobic portion of the quantum dot form micelles through the interaction between the ligands. Then, the micelle is coated with an organic material to form magnetic nanoparticles. In the formed magnetic nanoparticles, the surface of the quantum dot layer facing the magnetic nanoparticle core is modified with organic ligands, and the surface of the quantum dot layer facing away from the magnetic nanoparticle core has organic ligands, the quantum dots The surface of the layer facing away from the magnetic nanoparticle core is also modified with a surfactant, and the hydrophobic end of the surfactant is combined with the corresponding organic ligand.

In some embodiments, the material of the magnetic nanoparticle core is selected from ferrite particles, including but not limited to nanoscale superparamagnetic nanometer Fe ₃ O ₄ , γ-Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe Any one of ₂ O ₄ and MnFe ₂ O ₄ . The material of the magnetic nanoparticle core is selected from superparamagnetic nano Fe ₃ O ₄ (MNP).

In some embodiments, the quantum dots constituting the quantum dot layer are core-shell quantum dots, and the materials of the quantum dot core are group II and group VI elements. The group II elements include but are not limited to Zn, Cd, Hg, Cn, etc.; the group VI elements include but are not limited to O, S, Se, Te, Po, Lv, etc. As an example, the quantum dots are CdSe-CdS core-shell quantum dots.

In some embodiments, the organic shell material is polyvinylpyrrolidone. Since the quantum dot layer and the magnetic nanoparticle core are combined by the effect of a solvent, in order to make it stable, an organic shell layer is coated outside the quantum dot layer.

In some embodiments, the surfactant in the surfactant-containing aqueous solution is selected from tetradecyl ammonium bromide, cetyl trimethyl ammonium bromide, and dodecyl trimethyl ammonium bromide Kind of. The solvophobic used in this disclosure functions as a surfactant.

As shown in FIG. 3, the present disclosure also provides a method for preparing magnetic quantum dots, including the following steps:

S100. Add quantum dots and magnetic nanoparticles to an aqueous solution containing a surfactant, and mix the quantum dots to coat the outer surface of the magnetic nanoparticle core to obtain a micellar solution in which the quantum dot layer coats the magnetic nanoparticle core;

S200. Mix the micellar solution of the quantum dot layer with the magnetic nanoparticle core and the organic shell material, and coat the organic shell material on the outer surface of the quantum dot layer to obtain the magnetic quantum dot.

The magnetic quantum dots prepared by the method disclosed in the present disclosure use magnetic nanoparticles as the core and coat a layer of quantum dots on the core, which does not affect the performance of the quantum dots, but also makes the quantum dots magnetic, and then in the quantum The dot layer is coated with an organic layer to protect the quantum dot layer and enhance the stability of the particles.

In some embodiments, in the preparation method of the magnetic quantum dots, organic ligands are bound to the surfaces of the quantum dots and the magnetic nanoparticles. The ligands bound to the surfaces of the quantum dots and the magnetic nanoparticles may be the same or different, and the organic ligands are organic ligands containing thiol groups. Preferably, the mercapto group-containing organic ligand is selected from one or more of monothiol, dithiol, mercapto alcohol, mercaptoamine and mercapto acid. Further preferably, the monothiol is selected from the group consisting of thiol, octyl mercaptan, nonyl mercaptan, decyl mercaptan, undecane thiol, dodecane thiol, tridecane thiol, tetradecane thiol, hexadecane thiol One or more of alcohol and octadecanethiol.

In some embodiments, the material of the magnetic nanoparticles is selected from ferrite particles, including but not limited to nanoscale superparamagnetic nanometer Fe ₃ O ₄ , γ-Fe ₂ O ₃ , CoFe ₂ O ₄ , NiFe ₂ Any one of O ₄ and MnFe ₂ O ₄ . The material of the magnetic nanoparticles is selected from superparamagnetic nano Fe ₃ O ₄ (MNP).

In some embodiments, in the method for preparing magnetic quantum dots, quantum dots and magnetic nanoparticles are dissolved in an organic solvent to obtain a mixed solution; the organic solvent includes but is not limited to chloroform, n-octane, n-hexane, and toluene . The mixed solution in which quantum dots and magnetic nanoparticles are dissolved is injected into an aqueous solution containing a surfactant, and the mixed solution and the aqueous solution are thoroughly mixed by relative motion by means of vortex stirring and vibration. In the process of relative motion, because the magnetic nanoparticles are magnetic, they will gather together due to the magnetic force after the relative motion to form a magnetic nanoparticle core. At the same time, during the relative motion, the quantum dots and the magnetic The hydrophobic agent bound by the nanoparticle ligand will partly fall off, causing the hydrophobic surface ligand to be exposed. Because the solvent is water and the ligand is hydrophobic, the quantum dot will interact with the magnetic The nanoparticles are combined to coat the quantum dot layer on the surface of the magnetic nanoparticle core.

In some embodiments, in the preparation method of the magnetic quantum dots, the magnetic nanoparticle core and the quantum dot are formed of micelles by the hydrophobic ligand on the surface of the quantum dot and the hydrophobic ligand on the surface of the magnetic nanoparticle core, and are blown into the solution at room temperature Inert gas, which may be nitrogen, argon, helium, etc. The organic solvent was blown out to obtain a clear aqueous solution of quantum dot-magnetic nanoparticle core micelles.

In some embodiments, in the method for preparing magnetic quantum dots, an aqueous solution of the obtained quantum dots-magnetic nanoparticle core micelles is used. Mix at room temperature. In one example, stir during the mixing process. For example, the stirring speed is 600-800 rpm. Quickly pour into the solvent containing organic materials. After stirring, centrifugal separate to obtain the organic shell layer coated quantum dot layer and Magnetic nanoparticle core particles. The organic material includes but is not limited to polyvinylpyrrolidone, polyvinyl alcohol, polyethylene glycol and the like.

The present disclosure also provides an ink cartridge. As shown in FIG. 4, it includes an ink cartridge body and a nozzle 100. An electromagnetic field generator 300 is also provided between the ink cartridge body and the nozzle; the ink cartridge body contains ink 200 The ink contains magnetic quantum dots and non-magnetic quantum dots; the magnetic quantum dots are the above-mentioned magnetic quantum dots or the magnetic quantum dots obtained by the above-mentioned preparation method. Among them, the purpose of the electromagnetic field generator is to provide a magnetic field as long as its intensity is controllable.

The following further explains the present disclosure through specific embodiments.

In the following embodiments, the ink cartridge contains two kinds of ink, wherein the magnetically-doped ink is represented by M, and the ordinary ink is represented by N.

Example 1

Combined with 4mg red CdSe-CdS core-shell quantum dots and 6mg nano superparamagnetic nano-iron tetroxide (MNP) (quantum dots, magnetic nano particles combined with organic ligands, as shown in Figure 2a, 1 means CdSe-CdS core Shell quantum dots, 2 for magnetic nanoparticles, 3 for organic ligands) in 1 ml of chloroform solution into 1 ml of dodecyltrimethylammonium bromide (DTAB) aqueous solution (20 mg/ml in ultrapure water), (QDs and After the MNPs are modified, as shown in Figure 2b, 4 means DTAB). The solution was mixed thoroughly by vortexing for 5 seconds. By blowing Ar at room temperature to remove chloroform from the mixture, the red CdSe-CdS core-shell quantum dots and nano-superparamagnetic nano-iron tetroxide are bound by Together, we get a clarified micelle aqueous solution of red CdSe-CdS core-shell quantum dots and nano-superparamagnetic nano-iron tetroxide (red CdSe-CdS core-shell quantum dots and nano-superparamagnetic nano-iron tetroxide form micelles The process is shown in Figure 2c. The DTAB in the middle of c indicates the falling DATB).

The micelle solution was rapidly injected into 5 ml of polyvinylpyrrolidone (PVP) in ethylene glycol (EG) solution at room temperature with a stirring speed of 700 rpm for 30 minutes, and the resulting magnetically doped core-shell structure was separated by centrifugation Red quantum dot ultra-nano particles.

Injecting magnetically-doped red quantum dots M and ordinary non-magnetic blue quantum dots N into the ink cartridge provided by the present disclosure, the blue and red printing in the same ink cartridge can be controlled by the magnetic field Quantum dots.

Example 2

Inject 1ml of chloroform solution containing 4mg red CdSe-CdS core-shell quantum dots and 6mg nano superparamagnetic nano iron trioxide (MNP) into 1ml aqueous solution of dodecyl trimethyl ammonium bromide (DTAB) (20mg/ml in Ultra-pure water). The solution was mixed thoroughly by vortexing for 5 seconds. By blowing Ar at room temperature to remove chloroform from the mixture, the red CdSe-CdS core-shell quantum dots and nano-superparamagnetic nano-iron tetroxide are bound by Together, a clear micelle aqueous solution of red CdSe-CdS core-shell quantum dots and nano-superparamagnetic nano-iron tetroxide was obtained.

The micelle solution was quickly injected into 5 ml of polyvinylpyrrolidone (PVP) in ethylene glycol (EG) solution at room temperature with a stirring speed of 800 rpm for 30 minutes, and the resulting magnetically doped core-shell structure was separated by centrifugation Red quantum dot ultra-nano particles.

Injecting magnetically-doped red quantum dots M and ordinary non-magnetic green quantum dots N into the ink cartridge provided by the present disclosure can control the printing of green and red quanta in the same ink cartridge by a magnetic field point.

Example 3

Inject 1ml of chloroform solution containing 4mg green CdSe-CdS core-shell quantum dots and 6mg nano superparamagnetic nano iron trioxide (MNP) into 1ml of dodecyl trimethyl ammonium bromide (DTAB) aqueous solution (20mg/ml in Ultra-pure water). The solution was mixed thoroughly by vortexing for 5 seconds. By blowing Ar at room temperature to remove chloroform from the mixture, the red CdSe-CdS core-shell quantum dots and nano-superparamagnetic nano-iron tetroxide are combined in Together, a clear micelle aqueous solution of red CdSe-CdS core-shell quantum dots and nano-superparamagnetic nano-iron tetroxide was obtained.

The micelle solution was rapidly injected into 5 ml of polyvinylpyrrolidone (PVP) in ethylene glycol (EG) solution at room temperature with a stirring speed of 600 rpm for 30 minutes, and the resulting magnetically doped core-shell structure was separated by centrifugation Red quantum dot ultra-nano particles.

Injecting magnetically-doped green quantum dots M and ordinary non-magnetic blue quantum dots N into the ink cartridge provided by the present disclosure can control blue and green printing in the same ink cartridge by a magnetic field Quantum dots.

In summary, the quantum dots provided by the present disclosure have magnetic properties, which can be prepared into inks of different colors according to actual needs, and the resulting inks also have certain magnetic properties, which are mixed with ordinary inks and injected into the ink cartridges of the present disclosure In the process, by controlling the intensity of the electromagnetic field provided at the nozzle of the ink cartridge, controlling the content of the magnetic ink in the output ink, and adjusting the composition of the output ink, the printing efficiency and the utilization rate of the ink cartridge are effectively improved.

It should be understood that the application of the present disclosure is not limited to the above examples, and those of ordinary skill in the art may make improvements or changes based on the above description, and all such improvements and changes shall fall within the protection scope of the claims appended to the present disclosure.

Claims

A magnetic quantum dot, characterized in that the magnetic quantum dot includes a magnetic nanoparticle core, a quantum dot layer coated on the outer surface of the magnetic nanoparticle core, and an organic layer coated on the outer surface of the quantum dot layer Shell.
The magnetic quantum dot according to claim 1, wherein the surfaces of the quantum dots constituting the quantum dot layer and the magnetic nanoparticles constituting the magnetic nanoparticle core are modified with organic ligands, and the magnetic nanoparticles The core and the quantum dot layer are combined through the organic ligand.
The magnetic quantum dot according to claim 2, wherein the surface of the quantum dot layer facing away from the magnetic nanoparticle core is modified with the organic ligand, and the quantum dot layer facing away from the magnetic nanoparticle core The surface is also modified with a surfactant, and the hydrophobic end of the surfactant is bound to the corresponding organic ligand.
The magnetic quantum dot according to claim 1, wherein the organic shell material is one of polyvinylpyrrolidone, polyvinyl alcohol, and polyethylene glycol.
The magnetic quantum dot according to claim 1, wherein the organic ligand is a mercapto group-containing organic ligand.
The magnetic quantum dot according to claim 1, wherein the magnetic nanoparticle core material is selected from Fe 3 O 4 , γ-Fe 2 O 3 , CoFe 2 O 4 , Ni Fe 2 O 4 and Mn Fe 2 At least one of O 4 .
The magnetic quantum dot of claim 3, wherein the hydrophilic end of the surfactant is combined with the organic shell layer on the outer surface of the quantum dot layer.
The magnetic quantum dot according to claim 3, wherein the surfactant in the surfactant-containing aqueous solution is selected from the group consisting of tetradecyl ammonium bromide, cetyl trimethyl ammonium bromide and twelve One of alkyl trimethyl ammonium bromide.
The magnetic quantum dot according to claim 5, wherein the organic ligand containing a mercapto group is selected from one or more of monothiol, dithiol, mercaptoalcohol, mercaptoamine and mercaptoacid.
A method for preparing magnetic quantum dots, characterized in that it includes the steps of:

Add quantum dots and magnetic nanoparticles to an aqueous solution containing a surfactant, and mix the quantum dots to coat the outer surface of the magnetic nanoparticle core to obtain a micellar solution of the quantum dot layer covering the magnetic nanoparticle core;

The micelle solution coated with the magnetic nanoparticle core by the quantum dot layer is mixed with the organic shell material to coat the outer surface of the quantum dot layer with the organic shell material to obtain the magnetic quantum dot.
The method for preparing magnetic quantum dots according to claim 10, wherein the surfactant in the surfactant-containing aqueous solution is selected from tetradecyl ammonium bromide, cetyl trimethyl ammonium bromide and One of dodecyl trimethyl ammonium bromide.
The method for preparing magnetic quantum dots according to claim 10, characterized in that, in the step, quantum dots and magnetic nanoparticles are added to an aqueous solution containing a surfactant, and the quantum dots are coated to surround the magnetic nanoparticle cores On the surface, a micelle solution obtained by coating the magnetic nanoparticle core with the quantum dot layer includes:

Dissolve quantum dots and magnetic nanoparticles in an organic solvent to obtain a mixed solution;

After the mixed solution is added to the aqueous solution containing the surfactant, relative movement occurs between the mixed solution and the aqueous solution;

During the relative movement, an inert gas is introduced to remove the organic solvent, so that the magnetic nanoparticle cores are agglomerated, and part of the surfactant on the surface of the quantum dots falls off to expose the organic ligands. The ligand forms a solvophobic effect to obtain a micelle solution in which the quantum dot layer covers the magnetic nanoparticle core.
The method for preparing magnetic quantum dots according to claim 10, characterized in that in the step, the micelle solution coated with the magnetic nanoparticle core of the quantum dot layer is mixed with the organic shell material to make the organic shell material Wrapping the outer surface of the quantum dot layer to obtain the magnetic quantum dot specifically includes:

The micelle solution coated with the magnetic nanoparticle core of the quantum dot layer is added to the solution containing the shell layer material, and the organic shell layer material is coated on the outer surface of the quantum dot layer to obtain the magnetic quantum dot.
The method for preparing magnetic quantum dots according to claim 10, wherein the magnetic nanoparticle material is selected from Fe 3 O 4 , γ-Fe 2 O 3 , CoFe 2 O 4 , Ni Fe 2 O 4 and Mn Fe At least one of 2 O 4 .
An ink cartridge, including an ink cartridge body and a nozzle, characterized in that an electromagnetic field generator is further provided between the ink cartridge body and the nozzle; the ink cartridge body contains ink, and the ink contains magnetic quantum dots and non-magnetic Magnetic quantum dots; the magnetic quantum dots are made of the magnetic quantum dots of claims 1-9 or any of the magnetic quantum dots of claims 10-14.