KR102036149B1 - Apparatus for synthesizing quantum dot using screw reactor - Google Patents

Abstract

The present invention, precursor synthesis unit for synthesizing the precursor for generating quantum dot nanoparticles; A core synthesis unit generating a quantum dot core from the core by a precursor generated from the precursor synthesis unit; And a core / shell synthesis unit for synthesizing the quantum dot core / shell by the quantum dot core synthesized by the core synthesis unit, wherein the precursor synthesis unit, the core synthesis unit, and the core / shell synthesis unit are helically. Provided is a quantum dot synthesizing apparatus comprising a twisted screw type reaction tube.

Description

Quantum dot synthesis apparatus using screw reaction tube {APPARATUS FOR SYNTHESIZING QUANTUM DOT USING SCREW REACTOR}

The present invention relates to a quantum dot synthesizing apparatus, and more particularly, to a quantum dot synthesizing apparatus capable of simplifying a quantum dot synthesizing process and synthesizing quantum dots with uniform particle size and high emission intensity.

Quantum dots refer to semiconductor crystals (Crystalline) of nanometer size, and the characteristics change according to the band gap difference of the nanocrystals according to the particle size. When electrons in the quantum dot receive energy such as light, the energy level rises to the high energy level and then moves back to the low energy level. In this process, the wavelength of the energy emitted by the electron is emitted in the form of light. The wavelength of the light emitted by both is different according to the particle size and can express various colors, and it is used for display technology because of its excellent color reproducibility.

The conventional technique mainly used for such quantum dot synthesis is a solution process method. 1 is a view for explaining a conventional solution process method. As shown in FIG. 1, a device for synthesizing a quantum dot by a conventional solution processing method includes a magnetic force capable of uniformizing the flask 2 and the solution inside the flask 2 surrounded by a heating mantle 1. It consists of a stirrer (3), a thermostat (4) and a thermocouple (4) to control the temperature of the solution. In addition, it consists of a condenser (5) for maintaining a stable concentration and a manifold (manifold, 6) that can switch the vacuum / nitrogen atmosphere.

The method for synthesizing quantum dots by using such a device is stable by synthesizing a core using an organic compound that is a precursor, and repeatedly injecting a precursor to build an appropriate shell in a reactor in which the synthesized core and a stabilizer are mixed and stirred. In some cases, a core / shell structure of a structure is formed, and a method of adding a shell process to all the reactants at once by a one-pot process has been proposed.

Such a solution process method uses an impeller instead of a magnetic stirrer for uniform composition in the reactant when the capacity is increased, but a concentration difference and a composition difference occur in the reactant due to uneven temperature difference and uneven atmosphere.

Quantum dot synthesis is Oswald ripening, a function of temperature and time, and small particles are known to grow as they coalesce into relatively large particles, and require technology to stop the growth of particles when nanoparticles of desired size are formed. do. However, the conventional method is difficult to synthesize particles of uniform size because a temperature difference occurs during cooling to stop the growth of the particles. Therefore, these factors affect the luminescence properties and uniform particle size distribution of quantum dot nanoparticles.

The conventional quantum dot synthesis method known in the art will be described in detail as an example of a quantum dot synthesis method having a CdSe / CdZnS / ZnS structure.

1) Synthesis of precursor (precursor)

The Cd precursor is placed in a three-necked flask with oleic acid and cadmium oxide at a molar concentration between 0.05 and 1.0, and is completely dissolved and cooled at 170 degrees with rapid stirring in a nitrogen atmosphere.

Se precursor is measured by dissolving trioctylphosphine (Trioctylphosphine) and Se powder in a flask of oxygen-blocked atmosphere to a molar concentration of 0.7 ~ 1.5M and completely dissolved at room temperature.

Zn precursor weighs 1-octadecene, oleic acid, and zinc oxide to a molar concentration of 0.5 to 1.5 M, and dissolves completely at 300 degrees with rapid stirring in a nitrogen atmosphere. Keep it between 150 degrees.

The S precursor was weighed to 0.1M with 1-octadecene and S powder and dissolved completely at 120 ° C with rapid stirring in a nitrogen atmosphere.

These synthesis temperatures and molar ratios may vary depending on the desired wavelength.

2) core synthesis

The core is weighed with trioctylphosphine oxide, 1-octadecene, and Cd precursor in a flask, and the solution is 270-290 degrees with rapid stirring in a saturation atmosphere, followed by oleylamine ( Oleylamine) and Se precursors are rapidly injected and maintained at temperatures between 250 and 270 degrees.

Since the retention time is nanoparticles grow as a function of temperature and time according to the Oswald ripening theory, the retention time is maintained after cooling the target wavelength, that is, the size of the nanoparticles. During cooling, quenching is performed to prevent the nanoparticles from growing during cooling. Unnecessary organic matter contained in the cooled nanoparticles is centrifuged to remove suspended organic matter.

3) core / shell synthesis

Put the core synthesized with 1-octadecene (Octadecene) and oleylamine (Oleylamine) in the flask and the temperature is raised while stirring rapidly in a nitrogen atmosphere. The necessary elements for obtaining the desired emission wavelength are the wavelength of the core and the thickness of the shell. This is because the particle size correlates with the emission wavelength.

When the temperature reaches 70 degrees, Cd and Zn precursors are injected rapidly to build up the first layer of the shell, and Cd, Zn precursors and S precursors are rapidly maintained after injecting the shell two layers between 220 and 250 degrees. . In this order, you build the necessary shells.

5) Washing and Particle Separation

When the shell stacking process is finished at 220 ~ 250 ° C, keep it for about 10 ~ 30 minutes to stabilize the surface. It is quenched to obtain nanoparticles of constant size. Reaction by-products and organics remain in the reactants, so the organics are removed by centrifugation.

Separation of nanoparticles is carried out by centrifugation to separate the particles by size using a strong solvent, acetone or ethanol. The rapid stirring of the reactants during each reaction is a forced stirring using a magnetic bar or an agitator, but it is a method known as relatively uniform stirring. However, the reaction stirring speed varies depending on the amount of the reactants. May affect stable nanoparticle formation.

Such conventional quantum dot synthesis method requires a pre-circuit reactor, a reactor for cores, a reactor for cores / shells separately, and there is a disadvantage that a continuous process is impossible because it is synthesized by weighing and measuring again after each reaction. In addition, there is a problem in that it is difficult to obtain nanoparticles having uniform properties due to differences in reaction time, particle separation, and the like.

The present invention is to solve the problems of the prior art as described above, to simplify the quantum dot synthesis process, to be able to synthesize the quantum dots at a uniform temperature and conditions, quantum dot synthesis that can be controlled by the optimal quantum dot synthesis time An object of the present invention is to provide an apparatus and a method for synthesizing a quantum dot.

Another object of the present invention is to provide a quantum dot synthesizing apparatus and method capable of synthesizing quantum dots through a series of continuous processes from a free cursor to a core / shell process.

Another object of the present invention is to provide a synthesis apparatus and a synthesis method capable of synthesizing quantum dots having uniform nanoparticle sizes and thus synthesizing quantum dots with quantum efficiency and color purity.

In order to solve the above problems, the present invention, precursor synthesis unit for synthesizing the precursor for generating quantum dot nanoparticles; A core synthesis unit generating a quantum dot core from the core by a precursor generated from the precursor synthesis unit; And a core / shell synthesis unit for synthesizing the quantum dot core / shell by the quantum dot core synthesized by the core synthesis unit, wherein the precursor synthesis unit, the core synthesis unit, and the core / shell synthesis unit are helically. Quantum dot synthesizing apparatus comprising a twisted screw type reaction tube.

Here, it is preferable that the twisting interval of the screw-shaped reaction tube is partially different, so that the flow rate of the reactant is controlled.

In addition, the kink interval is narrower than other parts of the screw-type reaction tube to increase the flow rate of the reactant to allow washing and particle separation, and the kink interval is wider than other parts of the screw-type reaction tube to slow the flow rate of the reactant. It is preferable to allow the suspended matter to be discharged.

In addition, the length and the inner diameter of the screw-shaped reaction tube may be partially formed differently.

In addition, at least one groove may be formed on an inner surface of the screw-shaped reaction tube in a direction perpendicular to the twisting direction.

In addition, the outside of the screw-shaped reaction tube is filled with a liquid medium capable of temperature control, the liquid medium can be circulated controlled by a heating device or a cooling device to adjust the temperature of the screw reaction tube.

The precursor synthesis unit may include a cadmium precursor synthesis unit synthesizing a cadmium precursor; A sulfur precursor synthesis unit for synthesizing a sulfur precursor; Zinc precursor synthesis unit for synthesizing the zinc precursor; And a selenium precursor synthesis unit for synthesizing the selenium precursor.

In addition, the core / shell synthesis unit, it is preferable that the injection hole into which the precursor, the core, or the reaction raw material is injected is positioned at a predetermined length of the screw-type reaction tube.

In addition, the core / shell compounding unit may have an injection hole in which a precursor is injected at a predetermined position according to the number of layers of the shell.

According to the present invention, it is possible to provide a quantum dot synthesizing apparatus and a quantum dot synthesizing method capable of simplifying the quantum dot synthesizing process, allowing quantum dots to be synthesized at uniform temperatures and conditions, and controlling the optimal quantum dot synthesizing time.

In addition, the present invention can provide a quantum dot synthesizing apparatus and method capable of synthesizing quantum dots through a series of continuous processes from a free cursor to a core / shell process.

In addition, the present invention may provide a synthesis apparatus and a synthesis method capable of synthesizing quantum dots having a uniform nanoparticle size and thus quantifying quantum dots having a clear quantum efficiency and color purity.

1 is a view for explaining a conventional solution process method.
2 is a view showing an embodiment of the quantum dot synthesizing apparatus 100 according to the present invention.
3 to 5 are diagrams for explaining the screw reaction tube 40 of the precursor synthesis unit 10, the core synthesis unit 20, and the core / shell synthesis unit 30.
6 is a diagram for explaining the precursor synthesis unit 10.
7 is a diagram for explaining the core combining unit 20.
8 is a diagram for explaining the core / shell synthesis unit 30.
9 is a photograph of the quantum dot nanoparticles produced by the quantum dot synthesis apparatus 100 according to the present invention irradiated with ultraviolet rays, FIG. 10 shows light emission characteristics, and FIG. 11 shows light absorption characteristics.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a view showing an embodiment of the quantum dot synthesizing apparatus 100 according to the present invention.

Referring to FIG. 2, the quantum dot synthesizing apparatus 100 of the present embodiment includes a precursor synthesizing unit 10, a core synthesizing unit 20, and a core / shell synthesizing unit 30.

Here, the precursor synthesizing unit 10, the core synthesizing unit 20, and the core / shell synthesizing unit 30 are screw-shaped reaction tubes 40 (hereinafter referred to as “screw reaction tubes 40”). And they are connected to each other to enable a continuous process.

3 to 5 are diagrams for explaining the screw reaction tube 40 of the precursor synthesis unit 10, the core synthesis unit 20, and the core / shell synthesis unit 30.

3 and 5, the precursor synthesis unit 10, the core synthesis unit 20, and the core / shell synthesis unit 30 are formed of a reaction tube 40 in the form of a screw twisted spirally.

Herein, the screw reaction tube 40 may be formed to have different twist intervals as shown in FIG. 4 according to the requirements of each process.

The wider the twist interval, the faster the reaction time, and narrower, the narrower the reaction time. Each process is a function of the reaction time, so that the reaction time can be controlled by changing the twist interval partially.

In addition, the length of the screw-shaped reaction tube 40 can be adjusted according to the process needs. The longer the reaction tube, the longer the reaction time, and the shorter the shorter the reaction time. By controlling the reaction time by adjusting the length of the screw reaction tube 40, it was possible to reduce the unnecessary reaction time when quantum dot synthesis.

In addition, by adjusting the inner diameter of the reaction tube 40 in the form of a screw to vary the flow rate of the reactants passing through the reaction tube, it is possible to change the reaction time and synthesis conditions. The larger the inner diameter, the slower the flow rate, so the reactant in the reaction tube stops for a while, and the smaller the inner diameter, the faster the flow rate.

The length and the inner diameter of the screw reaction tube 40 may also be formed to be different from each other in part and even in each process.

On the other hand, the inner surface of the reaction tube 40 of the screw type, as shown in Figure 5, a plurality of grooves 41 may be formed in the vertical direction of the twisting direction. In other words, by forming a groove to be opposite to the curvature of the screw, the bubbling effect is generated by friction when the fluid reactant flows at a certain pressure by the groove, so that the stirring is more stable and uniform than that of the magnetic bar or agitator. Do it. Therefore, the stirring effect is raised.

The groove 41 may also be formed in the whole of the screw reaction tube 40 but may be partially formed only in part according to the process requirements.

Referring again to FIG. 2, the exterior of the screw reaction tube 40 is filled with water or oil, which is a temperature controllable liquid medium, which is connected to a separately connected heating or cooling device (see FIGS. 6 to 8). By controlling the circulation by the temperature of the screw reaction tube 40 is adjusted. By this structure, the synthesis conditions of the beginning and the end of the screw reaction tube 40 can be made the same.

The heating zone 44 is connected to the heating device and is circulated and supplied at a constant reaction temperature, and the cooling zone 45 is configured to be circulated and supplied at a constant cooling temperature through the cooling device.

The quick turn / centrifugal separator 42 may be made by making the twist interval of the screw-shaped reaction tube 40 smaller than elsewhere. Here, the particle separation process by washing and centrifugation is performed, but it is also possible by changing the internal diameter in this part as needed.

Washing and particle separation processes are made possible by changes in curvature and diameter of the screw reaction tube 40. If a certain amount of ethanol or acetone is injected into the starting point of passage when the curvature is large and the diameter is small, the reaction vapor pressure is generated, causing the reactant to bubbling and increasing the diameter by three times or more to control the flow rate. If this is reduced, the same effect as separating the particles through centrifugation can be obtained.

The float discharge port 43 is formed to have a gentle curvature by widening the twist interval, through which impurities or floats are discharged. In this case, since the flow rate is slow, the upper and lower parts are separated, and the organic matter, which is suspended in the upper part, is removed, and only the reactant in the lower part is transferred to the next process. If necessary, a solvent such as hexane may be used for a smooth flow.

The entire synthesis apparatus 100 is evacuated in order to remove internal impurities before the reaction, and reacts in an atmosphere of nitrogen, helium, argon, and the like, which are inert gases during the reaction. If necessary, there may be a pressure difference between the screw reaction tubes for a smooth flow of the reactant, and the moving speed of the reactant may be changed according to the pressure difference.

Once the reaction is complete, the reactants are configured to be transferred to and stored in a storage reaction vessel.

6 is a diagram for explaining the precursor synthesis unit 10.

The precursor synthesis unit 10 is a means for synthesizing a precursor for generating quantum dot nanoparticles, and as shown in FIG. 6, the precursor synthesis unit 10 includes a cadmium (Cd) precursor synthesis unit 11, At least one of a sulfur (S) precursor synthesis unit 12, a zinc (Zn) precursor synthesis unit 13 and a selenium (Se) precursor synthesis unit 14 is included.

As described above, each of the synthesis units 11, 12, 13, and 14 includes a screw-shaped reaction tube 40 twisted in a spiral shape, and connected to the heating device 112 and the cooling device 117, respectively. The heating part 115 and the cooling part 116 are provided.

The cadmium (Cd) precursor synthesis unit 11 operates as follows.

In order to make the cadmium precursor, the oleic acid (Oleic acid) and cadmium oxide (Cd oxide) in the inlet 111 is metered to a molar concentration between 0.05 ~ 1.0 and evacuated to a nitrogen atmosphere.

The liquid medium heated at 170 degrees in the heating device 112 is injected into the outside of the screw reaction tube through the inlet pipe 113, circulates outside the screw reaction tube, and comes out again through the discharge pipe 114 to the heating device 112. The temperature of the reaction tube is controlled while repeating the process of heating to a constant temperature and injecting / exiting the reaction tube again.

When the temperature of the screw reaction tube is constant at 170 degrees, the reactants injected through the injection port 111 using the nitrogen gas pressure are mixed while passing through the reaction tube 40 in the form of a screw.

At this time, the time required for the reaction can be adjusted by the length and the inner diameter of the screw reaction tube 40 as described above. In addition, as described above, the groove 41 is formed on the inner surface of the reaction tube 40 in the direction perpendicular to the twisting direction, so that stirring of the reactant may be made better.

Suitable inner diameter of the reaction tube for cadmium precursor synthesis is 0.5 to 3 cm, preferably 1 cm. The length of the screw tube is suitable to about 150cm when using a reaction tube of 1cm inner diameter.

The time taken for the reaction through the reaction tube 40 is between 3 and 7 minutes and the preferred reaction time is about 5 minutes and 30 seconds.

After the reaction is completed, the cadmium precursor is transferred to the cooling unit 116 and cooled by the cooling water supplied from the cooling device 117. The screw-shaped reaction tube of the cooling unit 116 is approximately 100 cm long, and is cooled while passing it for about 5 minutes, and the temperature of the cooling water is suitable for 50 to 60 degrees.

The cooled cadmium precursor is transferred to the core composite connector 118 at the time of core synthesis and to the core / shell composite connector 119 at the time of core / shell synthesis. In all reactions, the transport of reactants is forced by nitrogen gas. The nitrogen gas pressure can be changed at all times according to the inner diameter of the reaction tube 40 and the reaction time.

Next, the sulfur (S) precursor synthesis unit 12 operates as follows.

1-octadecene (Octadecene) and sulfur (S) powder is metered to 0.1 M through the inlet 111, and then evacuated to a nitrogen atmosphere. The temperature of the reaction tube 40 is the screw reaction tube 40 of the heating section 115 is heated as described above by the liquid medium heated by 120 degrees in the heating device 112, the screw reaction of 1cm and about 150cm inner diameter Synthesis is complete while passing through the tube for 5 minutes 30 seconds.

The synthesis of the sulfur precursor completed synthesis is completed while passing about 50 minutes 60 ~ 50 degree screw reaction tube of 100cm length of the cooling unit 117 is completed.

As with the cadmium precursor, it is transported using the pressure of nitrogen gas, and the core compounding tube 118 is used for core synthesis, and the core / shell compounding connector is used for core / shell synthesis. 119).

The zinc (Zn) precursor synthesis unit 13 operates as follows.

In order to synthesize the zinc precursor, 1-octadecene (Octadecene), oleic acid (Oleic acid) and zinc oxide (Zn oxide) are metered to a molar concentration of 0.5 to 1.5M in the inlet 111, and then evacuated to a nitrogen atmosphere. Switch to

The temperature of the reaction tube 40 is the screw reaction tube 40 of the heating unit 115 is heated by a liquid phase maintained at a temperature of 300 degrees in the heating device 112, the screw reaction tube of 1 cm and 200 cm inner diameter 5 minutes Synthesis is completed by passing for 30 seconds.

The synthesized reactant is transferred to the cooling unit 116 by the pressure of nitrogen gas injected into the tube, the length of the screw reaction tube of the cooling unit 116 is 100cm and the passage time is suitable for 5 minutes, the cooling unit 116 ) Is controlled to be maintained at 100 to 120 degrees by the cooling device (117).

These precursors of cadmium (Cd), sulfur (S), and zinc (Zn) harden when cooled to room temperature, and become gels or solids, so they are maintained at an appropriate temperature for a smooth reaction flow.

The selenium precursor synthesis unit 14 operates as follows.

In order to synthesize the Se (selenium) precursor, trioctylphosphine (Trioctylphosphine) and selenium (Se) powder is metered to a molar concentration of 0.7 to 1.5M in the inlet 111 and converted to a nitrogen atmosphere after vacuum evacuation.

The temperature of the reaction tube 40 is maintained by the heating device 112 to maintain the temperature of the heating unit 115 to 50 ~ 60 degrees, and synthesized while passing through the screw reaction tube having an inner diameter of 1cm, length of about 430cm for 10 minutes 30 seconds Is complete. Then, it is transferred to the core composite connector 118 for core synthesis.

7 is a diagram for explaining the core combining unit 20.

The core synthesizing unit 20 is a means for generating a quantum dot core from the core by the precursor generated from the precursor synthesizing unit 10. The core synthesizing unit 20 generates a quantum dot core by using auxiliary precursors for synthesizing the precursor and the core.

In FIG. 7, the core synthesizing unit 20 is connected to the cadmium precursor synthesizing unit 11 and the selenium precursor synthesizing unit 14 to receive a precursor generated therein.

As described above, the core synthesizing unit 20 is formed of a reaction tube 40 in the form of a screw, and is connected to the heating unit 25 and the cooling unit 26 connected to the heating unit 23 and the cooling unit 24. It is composed.

In addition, the screw-shaped reaction tube 40 of the core synthesis unit 20 is configured such that the twist intervals are partially different from each other as shown in FIG. 7.

As previously described, the narrow twist interval 28 functions as a quick turn / centrifugal portion and the wide twist interval 29 functions as a float discharge outlet.

The core synthesizing unit 20 operates as follows.

First, trioctylphosphine oxide and 1-octadecene (Octadecene) are metered into the first inlet 21, and oleylamine and selenium precursor synthesis unit are injected into the second inlet 22. The selenium precursor synthesized and transferred from (14) is weighed in and then evacuated to a nitrogen atmosphere. Then, the cadmium precursor from the cadmium precursor synthesis unit 11 is injected into the reaction tube 40 and mixed with the reactant injected into the first injection port 21.

The liquid phase heated to 270 to 290 degrees through the heating device 23 enters the heating unit 25 to fill the outside of the reaction tube 40 and circulates back to the heating unit 23 while heating unit 25 of the reaction tube 40. Keep the temperature constant.

The length of the screw reaction tube 40 for core synthesis is preferably 250 cm, and after 3 minutes and 20 seconds, the oleamine (2) is introduced into the second inlet 22 just before passing the second inlet 22 at the point of 100 cm. Oleylamine) and the selenium precursor transferred from the selenium precursor synthesis unit 14 are injected.

The reactants injected through the first inlet 21 and the second inlet 22 are mixed and reacted to grow the core. The size of the core required, that is, the determination of the emission wavelength can be controlled by the length and time of the screw reaction tube. According to the experiment, the following table shows the result.

After the reaction is completed, not only CdSe core but also impurities such as organic matter and by-products are mixed, and impurities must be completely removed to reduce crystallinity and defects.

To this end, the growing core is quenched to a desired size, and the reactant must be transferred to the cooling unit 26 to separate the core and impurities. In order to separate the CdSe core and impurities, ethanol, acetone and the like having strong polarity are injected into the third inlet 27, and the screw reaction as shown by the first flow rate control unit 28 and the second flow rate control unit 29 is performed. The flow rate of the reactants is changed by changing the twist intervals of the tubes.

The cooling unit 26 is maintained at 0 to 4 degrees by the cooling device 211.

The reactant passing through the first flow rate control unit 28 of the screw reaction tube passes at a very high flow rate because of a narrow twisting interval, and passes through the 150-200 cm length of the reaction tube in about 5 minutes, and the second flow rate control unit In (29), because the twist interval is wide, that is, as the curvature becomes gradual, impurities such as relatively light organic matter float and flow through. At this time, the floats may be removed to the outside through the float discharge pipe 212, which is achieved by using a condenser to maintain a pressure slightly lower than the pressure of the reaction tube.

The purified CdSe core is transferred to the core / shell composite connector 213 for the shell process. Of course, the core reaction also transfers the reactants using the pressure of nitrogen.

8 is a diagram for explaining the core / shell synthesis unit 30.

Referring to FIG. 8, the core / shell synthesis unit 30 includes a heating unit 302 and a cooling unit 307 similar to the core synthesis unit 20, and includes a cadmium precursor synthesis unit 11 and a zinc free unit. It is connected to the cursor synthesizing unit 12, the sulfur precursor synthesizing unit 13, and the core synthesizing unit 20.

First, the CdSe core, 1-Octadecene, and Oleylamine transferred from the core synthesis unit 20 are metered into the first injection hole 301, and the vacuum is evacuated to nitrogen atmosphere.

Factors necessary for obtaining the desired emission wavelength are the wavelength of the core and the thickness of the shell. This is because the particle size correlates with the emission wavelength.

The temperature of the heating part 302 of the screw reaction tube is controlled and circulated by 220 to 250 degrees by the heating device 303. For example, when the temperature reaches 240 degrees, the reactant injected into the first injection hole 301 is heated and reacted along the screw reaction tube at a pressure of nitrogen.

The length of the reaction tube is preferably 300 cm, and the total reaction time depends on the number of layers in the shell.

The even numbered layer of the shell is preferable, and the reaction time for the shell of each layer is about 10 minutes at 100 cm. In order to stack the shell, the Cd precursor transferred from the cadmium precursor synthesis unit 11 and the Zn precursor from the zinc precursor synthesis unit 13 are injected into the second injection hole 303. Since these injections are injected at the pressure of nitrogen through the reaction tube, a separate vacuum evacuation is unnecessary.

After the injection, it passes through a 100 cm long reaction tube for 10 minutes and injects cadmium, zinc and sulfur precursors into the third inlet 304 to stack another layer. The precursors are reacted by injecting the fourth inlet 305 to stack, and the precursors are reacted by injecting the precursor into the fifth inlet 306 to stack four layers.

This shell can also improve the light emission characteristics by stacking the ZnS shell as the outermost shell. In this way, quantum dots of the core / shell structure of CdSe / CdZnS / ZnS are synthesized.

Like the cores, the reactants that have completed the reaction contain not only CdSe / CdZnS / ZnS quantum dots but also impurities such as organic materials and reaction by-products, and impurities must be completely removed to reduce crystallinity and defects. The reactant is transferred to the cooling unit 307 to separate the synthesized nanoparticles and impurities.

As in the core synthesis unit 20, ethanol, acetone, or the like having strong polarity is injected into the sixth injection hole 308 to separate the synthesized nanoparticles and impurities, and the first flow rate control unit 308 and the second flow rate. By forming a narrow or wide twist interval of the adjusting unit 309, it is possible to change the flow rate of the screw reaction tube to thereby remove impurities.

The cooling unit 307 is controlled to be maintained at 0 to 4 degrees by the cooling device 310, the reactants passing through the first flow rate control unit 308 of the screw reaction tube passes at a very high flow rate and the length of the reaction tube It passes through 150 ~ 200cm in about 5 minutes, and as the curvature is swiftly smoothed in the second flow rate control unit 309 of the screw reaction tube 40, relatively light impurities such as organic matter is suspended, at this time float discharge pipe 311 Float can be removed to outside. This can be done using a condenser that maintains a pressure slightly lower than the pressure of the reaction tube.

The purified CdSe / CdZnS / ZnS core / shell nanoparticles are discharged to the particle discharge unit 312.

Wherein the core and core / shell are ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, HgSe, HgTe, MgS, MgSe, MgTe, CaS, CaSe, CaTe, SrS, SrSe, SrTe, BaS, BaSe, BaTe , GaN, GaP, GaAs, GaSb, InN, InP, InSb, Ge, Si, and combinations thereof. In addition, if necessary, the core / shell synthesis unit 30 may further synthesize a quantum dot buffer layer including one or more combinations or lattice constants of similar elements stacked between the quantum dot core and the quantum dot shell.

The advantage of this core / shell process is that since the inlet for stacking the shell is located at a predetermined length of the screw reaction tube 40, it is possible to stack the shell of uniform size all the time. Even when stacking, the distance of the inlet can be controlled by arranging the inlet of Cd, Zn, S, etc. for stacking the shell in the screw reaction tube 40 at a predetermined position according to the calculated core size and the calculated stacked size. A uniform and flawless shell can be stacked.

On the other hand, the size of the quantum dot nanoparticles, that is, the emission wavelength is determined according to the wavelength of the core and the number of shells, and when a large number of shells are stacked in order to increase the size of the nanoparticles, the light emission characteristics are deteriorated. The number of floors is 4-6.

For example, stacking four layers on a 510nm core results in 525nm, and stacking six layers results in 530nm. In addition, stacking four layers on a 600nm core results in 620nm, and stacking six layers results in 625nm. Using this relationship, the emission wavelength of the quantum dot nanoparticles to be finally obtained can be determined by the size of the core and the number of shells.

Using the screw reaction tube as described above, it is possible to obtain quantum dot nanoparticles that are stable, uniform and free of impurities, have no defects, and have excellent light emitting characteristics.

9 is a photograph of the quantum dot nanoparticles produced by the quantum dot synthesizing apparatus 100 according to the present invention irradiated with ultraviolet rays, and FIG. 10 shows light emission characteristics, and FIG. 11 shows light absorption characteristics.

In the light emission characteristic of Fig. 10, the x axis is the emission wavelength (nm) and the y axis is the absolute intensity. The luminescence properties were measured at an excitation wavelength of 385 nm using a Horiba FluoroMax-4 Spectrofluorometer.

In the light absorption characteristic of FIG. 11, the x axis is an absorption wavelength (nm) and the y axis is an absolute intensity. Absorption characteristics were measured using an Agilent Cary300 Spectrophotometer.

Although the present invention has been described above with reference to preferred embodiments of the present invention, the present invention is not limited to the above embodiments, and various modifications / deformations may be made.

100.Quantum Synthesis Device
10.Precursor Synthesis
20 ... core composite
30 core / shell composite

Claims (9)

A precursor synthesis unit for synthesizing a precursor for generating quantum dot nanoparticles; A core synthesizing unit generating a quantum dot core from a core by a precursor generated from the precursor synthesizing unit; And a core / shell synthesis unit for synthesizing the quantum dot core / shell by the quantum dot core synthesized by the core synthesis unit.
The precursor synthesis unit, core synthesis unit, and core / shell synthesis unit include a screw-shaped reaction tube twisted spirally,
The twist interval of the screw-shaped reaction tube is formed to be different in part so as to control the flow rate of the reactant,
The screw-type reaction tube is a quick rotation part / centrifugal separation portion for washing and particle separation by making the twist interval narrower than other parts of the screw-type reaction tube to increase the flow rate of the reactant, and the twist interval is screw-shaped A quantum dot synthesizing apparatus characterized by comprising a float discharge port so that the suspended matter is discharged by wider than the other parts of the reaction tube to slow the flow rate of the reactants.
delete delete The method of claim 1,
The length and the inner diameter of the screw-shaped reaction tube is partially formed different quantum dot synthesis apparatus.
The method of claim 1,
At least one groove is formed on an inner surface of the screw-shaped reaction tube in a direction perpendicular to the twisting direction.
The method of claim 1,
The outside of the screw-type reaction tube is filled with a liquid medium capable of temperature control, the liquid medium is circulated controlled by a heating device or a cooling device to adjust the temperature of the screw reaction tube characterized in that the device.
The method of claim 1,
The precursor synthesis unit,
A cadmium precursor synthesizer for synthesizing the cadmium precursor;
A sulfur precursor synthesis unit for synthesizing a sulfur precursor;
Zinc precursor synthesis unit for synthesizing the zinc precursor; And
Selenium precursor synthesis section for synthesizing selenium precursor
Quantum dot synthesizing apparatus comprising at least any one of.
The method of claim 1,
The core / shell composite portion,
A quantum dot synthesizing apparatus, characterized in that the precursor, the injection hole in which the core or the reaction material is injected is located at a predetermined length of the screw-shaped reaction tube.
The method of claim 8,
The core / shell composite portion,
A quantum dot synthesizing apparatus, characterized in that the injection hole for the precursor is injected in a predetermined position according to the number of layers of the shell.

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