Reaction device and method for narrow-band light-emitting indium phosphide quantum dots

Abstract

The invention discloses a narrow-band light-emitting indium phosphide quantum dot reaction device and a method thereof. The reaction device comprises a supergravity device and a photo-thermal device, the supergravity device comprises a shell, a motor, a turntable, a shear filler, a liquid distributor, a reaction cavity, a filler cover, a gas outlet, a liquid outlet and a liquid inlet; the photo-thermal device comprises a laser heating device, a circuit and water cooling device, a reflecting layer and a laser controller; infrared laser is coupled into the supergravity reactor, water or organic matter and other solvent media are used for absorbing infrared light and converting the infrared light into heat energy to increase the temperature of the supergravity reactor, the nucleation reaction of reactant precursors in the micro-droplet reactor is excited, controllable growth of quantum dots in the micro-droplet reactor is achieved, and the quantum dots are obtained. And finally, nano-particles with uniform sizes are obtained by controlling the laser irradiation heating time.

Description

Technical Field

[0001] The present invention relates to the technical field of quantum dot nanomaterial preparation, in particular, to a reaction device and method for narrow-band luminescent indium phosphide quantum dots; more particularly, to a method for preparing InP / ZnSeS / ZnS core-shell quantum dots and a supergravity coupled photothermal reaction device. Background Art

[0002] The essence of the chemical preparation of indium phosphide (InP) quantum dots is to achieve precise control of 20-200 atomic collisions, splitting and rearrangement at the macroscopic reactor scale, which places extremely high demands on the coordination of nano- and micro-scale transmission and reaction. Hot injection is currently the most mature method for preparing InP quantum dots. Using tri(trimethylsilyl)phosphine [abbreviated as: (TMS)3P] as the P source and indium carboxylate as the In source, InP quantum dots with excellent optical properties can be obtained. However, it is limited in batch preparation. The solvothermal method has advantages in achieving large-scale preparation of InP quantum dots. Using tri(dimethylamino)phosphine [(DMA)3P] as the P source, InX3 (X=Cl, Br, I) as the In source, and oleylamine as the solvent, InP nanocrystalline particles of different particle sizes can be obtained by changing the ratio of different halogen elements. However, the existing liquid phase precipitation combined with solvothermal growth method is difficult to meet the precise control of InP quantum dot reaction nucleation and growth due to the limitation of the molecular mixing speed in the traditional stirred tank reactor.

[0003] A supergravity reactor is a typical chemical process intensification equipment. The liquid medium inside it flows in a porous medium in a supergravity environment that is hundreds to thousands of times larger than the earth's gravity field, and is torn into micrometer-scale or even nanometer-scale membranes, filaments, and droplets (that is, a large number of rapidly updated "micro-droplet reactors" are produced), so that the molecular diffusion, microscopic mixing, and mass transfer processes between molecules of different sizes are greatly enhanced. In a supergravity reactor, the microscopic molecular mixing and mass transfer processes are greatly enhanced, and the nanocrystal nucleation and growth process is carried out in a microscopically uniform ideal environment, which can form explosive uniform nucleation of nanocrystals, which is conducive to obtaining nanoparticles with small particle size and narrow distribution. For example, Chinese Patent Application No. 202110642064.1 discloses a method for preparing InP@ZnS core-shell quantum dots by a supergravity reactor and the resulting InP@ZnS core-shell quantum dots. However, the preparation of quantum dots in the InP system requires the use of external energy to break through the crystal nucleation energy barrier in order to stimulate the nucleation reaction of the precursor. Due to the existence of uneven heat flow in traditional ultra-gravity reactors, it is difficult to achieve explosive and uniform nucleation of InP crystal nuclei in an ideal state, resulting in poor uniformity of the product particle size distribution. The half-peak width of the resulting InP quantum dot emission spectrum is mostly above 50nm. Summary of the invention

[0004] The first technical problem to be solved by the present invention is to provide a reaction device for narrow-band luminescent indium phosphide quantum dots.

[0005] The second technical problem to be solved by the present invention is to provide a method for producing narrow-band luminescent indium phosphide quantum dots using the above reaction device.

[0006] In order to solve the above-mentioned first technical problem, the technical solution adopted by the invention is as follows:

[0007] A reaction device for narrow-band luminescent indium phosphide quantum dots, including a supergravity device and a photothermal device;

[0008] The supergravity device comprises a housing, a motor, a rotating disk, a shear filler, a liquid distributor, a reaction chamber, a filler cover, a gas outlet, a liquid outlet, and a liquid inlet;

[0009] The output shaft of the motor passes through the lower surface of the housing and extends into the housing to be fixedly connected to the turntable; at the same time, the top end of the output shaft of the motor is also fixedly connected to a liquid distributor located above the turntable;

[0010] An annular shear filler is arranged on the rotating disk, and the top of the shear filler is fixedly covered with a filler cover; a hollow reaction chamber is formed between the rotating disk, the shear filler and the filler cover;

[0011] A liquid outlet is provided on the bottom of the shell; the liquid inlet passes through the shell and is connected to the packing cover and the reaction chamber; a gas outlet is provided on the top of the shell;

[0012] The photothermal device includes a laser heating device, a circuit and a water cooling device, a reflective layer and a laser controller;

[0013] The reflective layer is arranged on the inner surface of the shell, and an interlayer is arranged between the reflective layer and the shell, and a circuit and a water cooling device are arranged in the interlayer; the laser heating device is arranged on the inner surface of the reflective layer, and the laser heating device is connected to the laser controller through the circuit in the interlayer.

[0014] Preferably, the filler cover is made of a transparent material to allow the laser to penetrate as much as possible.

[0015] Preferably, a turntable is fixed on the output shaft of the motor and drives it to rotate.

[0016] Preferably, the laser heating device includes one or more devices, which can be installed or removed as needed.

[0017] Preferably, the laser heating device is a laser with a wavelength of 980-1500nm.

[0018] Preferably, the power of the laser heating device is 20-500W.

[0019] In order to solve the above second technical problem, the technical solution adopted by the invention is as follows:

[0020] A method for producing narrow-band luminescent indium phosphide quantum dots using the above reaction device comprises the following steps:

[0021] 1) dissolving an indium precursor, a zinc precursor, and a phosphine precursor in an organic solvent respectively, and then introducing them into a supergravity reactor to react at a temperature of 110-130° C. to obtain an InP quantum dot core;

[0022] 2) dissolving zinc salt, sulfur powder and selenium powder in an organic solvent, and then introducing the mixture into the supergravity reactor of the InP quantum dot core to react, thereby obtaining InP / ZnSeS core-shell quantum dots;

[0023] 3) introducing the zinc salt and the thiol into the above-mentioned InP / ZnSeS core-shell quantum dots to react, and obtaining a reaction mixture I;

[0024] 4) Adding a poor solvent to the reaction mixture after the shell coating is completed and centrifuging it to obtain a precipitate which is narrow-band luminescent indium phosphide quantum dots.

[0025] Preferably, in step 1), the indium precursor is one of indium iodide, indium bromide and indium chloride.

[0026] Preferably, in step 1), the zinc precursor is one of zinc iodide, zinc bromide and zinc chloride.

[0027] Preferably, in step 1), the phosphine precursor is tris(dimethylamino)phosphine or tris(diethylamino)phosphine.

[0028] Preferably, in step 1), the organic solvent is one or more of oleylamine, octadecylamine, hexadecylamine, tetradecylamine and dodecylamine.

[0029] Preferably, in step 1), the molar ratio of indium ions in the indium precursor to zinc ions in the zinc precursor is 1:1-1:10.

[0030] Preferably, in step 1), the molar ratio of indium ions in the indium precursor to the phosphine precursor is 1:3-1:7.

[0031] Preferably, in step 1), the molar ratio of the indium precursor to the organic solvent is 1:20-1:100.

[0032] Preferably, in step 2), the zinc salt is one or more of zinc iodide, zinc bromide, zinc chloride, zinc stearate, zinc oleate, and zinc acetate.

[0033] Preferably, in step 2), the ratio of the selenium powder to the sulfur powder is 0:1-2:1.

[0034] Preferably, in step 2), the organic solvent is one of oleylamine, 1-octadecene, tri-n-octylphosphine and tri-n-octylphosphine oxide.

[0035] Preferably, in step 1 and step 2), the molar ratio of indium ions in the indium precursor to the zinc salt is 1:3-1:10.

[0036] Preferably, in step 1 and step 2), the ratio of the sum of the molar numbers of indium ions in the indium precursor and the sulfur powder and selenium powder is 1:3-1:10.

[0037] Preferably, in step 1) and step 2), the high gravity reactor is a high gravity rotating packed bed reactor; the rotation speed of the high gravity rotating packed bed reactor is 500 rpm-2000 rpm, and the reaction time is 1 s-60 min.

[0038] Preferably, in step 3), the thiol is one of dodecyl mercaptan, hexadecyl mercaptan and octyl mercaptan.

[0039] Preferably, in step 1) and step 3), the molar ratio of indium ions to the thiol in the indium precursor is 1:10-1:20.

[0040] Preferably, in step 4), the poor solvent is ethanol or acetone.

[0041] Any range described in the present invention includes the end value and any numerical value between the end values ​​and any sub-range formed by the end value or any numerical value between the end values.

[0042] Unless otherwise specified, all raw materials in the present invention can be purchased from the market, and the equipment used in the present invention can adopt conventional equipment in the relevant field or refer to the existing technology in the relevant field.

[0043] Compared with the prior art, the present invention has the following beneficial effects: :

[0044] 1) The ultra-gravity photothermal coupling reaction system proposed in the present invention uses the liquid medium obtained through the ultra-gravity shearing device as a "micro-droplet reactor". In the ultra-gravity reactor, the microscopic molecular mixing and mass transfer process are greatly enhanced, and the nanocrystal nucleation and growth process is carried out in a microscopic uniform ideal environment, which can form explosive uniform nucleation of nanocrystals, which is conducive to obtaining nanoparticles with small particle size and narrow distribution. Further, infrared laser is coupled into the ultra-gravity reactor, and the solvent medium such as water or organic matter is used to absorb infrared light and convert it into heat energy to increase its temperature, stimulate the nucleation reaction of the reactant precursor in the "micro-droplet reactor", realize the controllable growth of quantum dots in the micro-droplet reactor, and finally obtain nanoparticles of uniform size by controlling the laser irradiation heating time.

[0045] 2) At the same time, the present invention connects the vacuum pump and the nitrogen pipeline through double-row pipes, so that the entire reaction system can be carried out under nitrogen protection, ensuring that the reaction system is free of water and oxygen, so that the ultra-gravity equipment can be used for the quantum dot preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0047] Figure 1 This is a schematic diagram of the structure of a reaction device for narrow-band luminescent indium phosphide quantum dots of the present invention;

[0048] Figure 2 Schematic diagram of the overall structure of the reaction system in the embodiment of the present invention;

[0049] Figure 3 It is a schematic diagram of the process of synthesizing quantum dots according to the present invention;

[0050] Figure 4 Fluorescence spectra of InP / ZnSeS / ZnS quantum dots synthesized in Examples 1, 2, and 3;

[0051] Figure 5 is an X-ray diffraction (XRD) pattern of the InP / ZnSeS / ZnS quantum dots synthesized in Example 1;

[0052] Figure 6 is the X-ray photoelectron spectroscopy (XPS) spectrum of InP / ZnSeS / ZnS quantum dots synthesized in Example 1;

[0053] Figure 7 is a transmission electron microscope (TEM) image of the InP / ZnSeS / ZnS quantum dots synthesized in Example 1;

[0054] Figure 8 is a transmission electron microscope (TEM) image of the InP / ZnSeS / ZnS quantum dots synthesized in Example 2;

[0055] Fig. 9 is a transmission electron microscope (TEM) image of the InP / ZnSeS / ZnS quantum dots synthesized in Example 3;

[0056] Fig.10 The photos of the InP / ZnSeS / ZnS quantum dot dispersions synthesized in Examples 1, 2, and 3 under sunlight and 365nm excitation light;

[0057] Fig.11 The fluorescence spectra of InP / ZnSeS / ZnS quantum dots at different supergravity levels synthesized in Example 4;

[0058] Fig.12The full width at half maximum (FWHM) and quantum yield (PLQY) of InP / ZnSeS / ZnS quantum dots at different supergravity levels synthesized in Example 4;

[0059] Fig.13 This is the fluorescence spectrum of InP / ZnS quantum dots synthesized in Comparative Example 1.

[0060] Fig.14 This is a comparison chart of the quantum yield of InP / ZnSeS / ZnS quantum dots synthesized in Comparative Example 2.

[0061] Fig.15 This is the fluorescence spectrum of InP / ZnSeS / ZnS quantum dots synthesized in Comparative Example 3.

[0062] Fig.16 This is the UV-visible absorption spectrum of InP quantum dots synthesized in Comparative Example 4.

[0063] Digital Marking:

[0064] 1- housing;

[0065] 2- Motor;

[0066] 3- Turntable;

[0067] 4-shear filler;

[0068] 5-Liquid distributor;

[0069] 6- reaction chamber;

[0070] 7-Stuffing cover;

[0071] 8- Gas outlet;

[0072] 9 liquid outlet;

[0073] 11- first liquid inlet;

[0074] 12- second liquid inlet;

[0075] 21-Laser heating device;

[0076] 22-Circuit and water cooling device;

[0077] 23-reflection layer;

[0078] 24-Laser controller. DETAILED DESCRIPTION

[0079] In order to more clearly illustrate the present invention, the present invention is further described below in conjunction with preferred embodiments and accompanying drawings. Similar components in the accompanying drawings are represented by the same reference numerals. It should be understood by those skilled in the art that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present invention.

[0080] For the convenience of description, the descriptions of "first", "second", etc. in the present invention are only set for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various implementation methods can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0081] See also Figure 1 and Figure 2 As shown, as one aspect of the present invention, a reaction device of narrow-band luminescent indium phosphide quantum dots of the present invention comprises a supergravity device and a photothermal device;

[0082] The ultra-gravity device comprises a housing 1, a motor 2, a rotating disk 3, a shear filler 4, a liquid distributor 5, a reaction chamber 6, a filler cover 7, a gas outlet 8, a liquid outlet 9, and liquid inlets 11 and 12;

[0083] The output shaft of the motor 2 passes through the lower surface of the housing 1 and extends into the housing 1 to be fixedly connected to the turntable 3; at the same time, the top end of the output shaft of the motor 2 is also fixedly connected to a liquid distributor 5 located above the turntable 3; the fluid distributor 5 is fixed in the center of the reaction chamber to spray the reaction material into the entire space;

[0084] An annular shear filler 4 is arranged on the rotating disk 3, and a filler cover 7 is fixedly covered on the top of the shear filler 4; a hollow reaction chamber 6 is formed between the rotating disk 3, the shear filler 4 and the filler cover 7;

[0085] A liquid outlet 9 is provided on the bottom of the housing 1;

[0086] In the present invention, the liquid inlet is provided with two, including a first liquid inlet 11 and a second liquid inlet 12, and the liquid inlet passes through the shell 1 and the packing cover 7 to communicate with the reaction chamber 6; a gas outlet 8 is provided on the top of the shell 1;

[0087] The photothermal device includes a laser heating device 21, a circuit and water cooling device 22, a reflective layer 23 and a laser controller 24;

[0088] The reflective layer 23 is arranged on the inner surface of the shell 1, and an interlayer is arranged between the reflective layer 23 and the shell 1, and a circuit and a water cooling device 22 are arranged in the interlayer; the laser heating device 21 is arranged on the inner surface of the reflective layer 23, and the laser heating device 21 is connected to the laser controller 24 through the circuit in the interlayer.

[0089] In some embodiments of the present invention, the filler cap is made of a transparent material to allow the laser to pass through as much as possible.

[0090] In some embodiments of the present invention, a turntable is fixed on the output shaft of the motor and drives the motor to rotate.

[0091] In certain embodiments of the present invention, the laser heating device includes one or more devices, which can be installed or removed as needed; the laser heating device uses a laser controller to control the power of laser heating.

[0092] In certain embodiments of the present invention, the laser heating device is a laser with a wavelength of 980-1500 nm; the laser heating device uses a water cooling system to ensure the normal operating temperature of the laser.

[0093] In some embodiments of the present invention, the power of the laser heating device is 20-500W.

[0094] The present invention couples an infrared laser into a supergravity reactor, utilizes a solvent medium such as water or organic matter to absorb infrared light and convert it into heat energy to increase its temperature, and stimulates the nucleation reaction of the reactant precursor in the "droplet reactor". Since infrared light heating utilizes the principle of electromagnetic radiation heat transfer, it directly transfers heat to achieve the purpose of stimulating the reaction, thereby avoiding energy loss caused by heating the air, which not only saves energy but also has high speed and high efficiency. In addition, infrared rays have a certain penetrating ability, and the internal and surface solvent media of a certain depth of the "droplet reactor" absorb infrared radiation energy at the same time, generate heat evenly, promote uniform nucleation and growth of particles in the droplets, and are conducive to obtaining high-quality nanoparticle products. The supergravity coupled photothermal reactor formed by the fusion of supergravity technology and photothermal technology can greatly promote the mass transfer process. The interface reflection and scattering effect of a large number of microdroplets can make the light irradiation more evenly distributed in the entire supergravity reactor cavity, and improve the absorption and utilization of light irradiation energy. It solves the problem that traditional supergravity reactors are difficult to reach uniform heat distribution at higher temperatures, and can be used to prepare narrow-band luminescent indium phosphide quantum dots with a half-peak width of less than 50nm. As a sustainable energy source, the utilization of light energy has received close attention from researchers. Photothermal conversion is a ubiquitous energy conversion process in nature and human-developed systems. Due to its potential applications such as photothermal therapy, photothermal conversion has been widely studied. With the rapid development of nanotechnology in recent years, photothermal conversion at the micro-nano scale has received attention in many fields and played a key role. Since infrared light heating uses the principle of electromagnetic radiation heat transfer to transfer heat in a direct manner to achieve the purpose of stimulating the reaction, it avoids energy loss caused by heating the air. It not only saves energy but also is fast and efficient. In addition, infrared rays have a certain penetrating ability. The internal and surface solvent media of a certain depth of the "droplet reactor" absorb infrared radiation energy at the same time, generate heat evenly, and promote uniform nucleation and growth of particles in the droplets, which is conducive to obtaining high-quality nanoparticle products, such as Figure 3 shown.

[0095] The supergravity-coupled photothermal reactor formed by the fusion of supergravity technology and photothermal technology can greatly promote the mass transfer process. The interface reflection and scattering effects of a large number of microdroplets can make the light radiation more evenly distributed in the entire supergravity reactor cavity, thereby improving the absorption and utilization of light radiation energy.

[0096] As another aspect of the present invention, a method for producing narrow-band luminescent indium phosphide quantum dots using the above-mentioned reaction device comprises the following steps:

[0097] 1) dissolving an indium precursor, a zinc precursor, and a phosphine precursor in an organic solvent respectively, and then introducing them into a supergravity reactor to react at a temperature of 110-130° C. to obtain an InP quantum dot core;

[0098] 2) dissolving zinc salt, sulfur powder and selenium powder in an organic solvent, and then introducing the mixture into the supergravity reactor of the InP quantum dot core to react, thereby obtaining InP / ZnSeS core-shell quantum dots;

[0099] 3) introducing the zinc salt and the thiol into the above-mentioned InP / ZnSeS core-shell quantum dots to react, and obtaining a reaction mixture I;

[0100] 4) Adding a poor solvent to the reaction mixture after the shell coating is completed and centrifuging it to obtain a precipitate which is narrow-band luminescent indium phosphide quantum dots.

[0101] In certain embodiments of the present invention, in step 1), the indium precursor is one of indium iodide, indium bromide and indium chloride.

[0102] In certain embodiments of the present invention, in step 1), the zinc precursor is one of zinc iodide, zinc bromide and zinc chloride.

[0103] In certain embodiments of the present invention, in step 1), the phosphine precursor is tris(dimethylamino)phosphine or tris(diethylamino)phosphine.

[0104] In certain embodiments of the present invention, in step 1), the organic solvent is one or more of oleylamine, octadecylamine, hexadecylamine, tetradecylamine, and dodecylamine.

[0105] In certain embodiments of the present invention, in step 1), the molar ratio of indium ions in the indium precursor to zinc ions in the zinc precursor is 1:1-1:10.

[0106] In certain embodiments of the present invention, in step 1), the molar ratio of indium ions in the indium precursor to the phosphine precursor is 1:3-1:7.

[0107] In certain embodiments of the present invention, in step 1), the molar ratio of the indium precursor to the organic solvent is 1:20-1:100.

[0108] In certain embodiments of the present invention, in step 2), the zinc salt is one or more of zinc iodide, zinc bromide, zinc chloride, zinc stearate, zinc oleate, and zinc acetate.

[0109] In certain embodiments of the present invention, in step 2), the ratio of the selenium powder to the sulfur powder is 0:1-0:2, preferably.

[0110] In certain embodiments of the present invention, in step 2), the organic solvent is one of oleylamine, 1-octadecene, tri-n-octylphosphine, and tri-n-octylphosphine oxide.

[0111] In certain embodiments of the present invention, in step 1 and step 2), the molar ratio of indium ions in the indium precursor to the zinc salt is 1:3-1:10.

[0112] In certain embodiments of the present invention, in step 1 and step 2), the ratio of the sum of the molar numbers of indium ions in the indium precursor and the selenium powder and the sulfur powder is 1:3-1:10.

[0113] In certain embodiments of the present invention, in step 1) and step 2), the high gravity reactor is a high gravity rotating packed bed reactor; the rotation speed of the high gravity rotating packed bed reactor is 500rpm-2000rpm, and the reaction time is 1s-60min.

[0114] In certain embodiments of the present invention, in step 3), the thiol is one of dodecyl mercaptan, hexadecyl mercaptan and octyl mercaptan.

[0115] In certain embodiments of the present invention, in step 1) and step 3), the molar ratio of indium ions to the thiol in the indium precursor is 1:10-1:20.

[0116] In certain embodiments of the present invention, in step 4), the poor solvent is ethanol or acetone.

[0117] Example 1

[0118] The supergravity photothermal coupling device of the present invention is used to synthesize InP / ZnSeS / ZnS quantum dots.

[0119] 2.23g of indium iodide, 4.90g of zinc bromide, and 50ml of oleylamine were fully dehydrated and oxygenated at 120℃ for 60min. First, start the motor and laser heating device, set the speed and temperature to 1500r / min and 100℃ respectively, and pass the precursor solution into the supergravity device through a peristaltic pump. Turn on the vacuum pump to a vacuum gauge pressure of -0.086MPa, and then pass nitrogen for 5min. Repeat this process 3 times, then adjust the laser heating device to 180℃, and fully react under supergravity conditions for 30min to obtain InP quantum dot cores of uniform size;

[0120] Under nitrogen protection, 30 g of zinc stearate, 0.43 g of selenium powder and 0.35 g of sulfur powder dissolved in 10 ml of tri-n-octylphosphine were added to 100 ml of octadecene at 120 degrees Celsius, and introduced into the ultra-gravity reactor through a peristaltic pump. The laser heating device was adjusted to heat up to 240 degrees Celsius for shell coating, and the reaction was carried out for 30 minutes to obtain InP / ZnSeS quantum dots.

[0121] 15 ml of dodecyl mercaptan was introduced into the ultra-gravity reactor through a peristaltic pump for 10 min to obtain InP / ZnSeS / ZnS quantum dots;

[0122] The discharge solution was collected; anhydrous ethanol was added and centrifuged for purification three times to obtain a precipitate which was dispersed in n-hexane by ultrasonication to obtain the final product, InP / ZnSeS / ZnS core-shell quantum dot dispersion.

[0123] Figure 4 The emission spectrum of the obtained InP / ZnSeS / ZnS core-shell quantum dots has an emission peak of 529nm, showing green light, a half-peak width of 50nm, and a quantum yield of 71.46%.

[0124] Figure 5 The X-ray diffraction (XRD) diagram of the obtained InP / ZnSeS / ZnS core-shell quantum dots shows that the obtained product has an InP matching peak and a good crystal form. Figure 6 The X-ray photoelectron spectroscopy (XPS) spectrum of the obtained InP@ZnS core-shell quantum dots, in which In, P, Zn, S, and Se elements are present, Figure 7 : is a transmission electron microscope (TEM) image of the obtained InP / ZnSeS / ZnS core-shell quantum dots, and the core-shell quantum dots have good dispersion.

[0125] Fig.10 (a) is a photograph of the dispersion of the obtained InP / ZnSeS / ZnS core-shell quantum dots under 365nm daylight excitation light. It can be seen that the prepared core-shell quantum dots exhibit bright fluorescence.

[0126] Example 2

[0127] The indium precursor and zinc precursor were replaced with 1 g indium chloride and 7 g zinc iodide, and the rest of the reaction process and conditions remained unchanged.

[0128] Figure 4 This is the emission spectrum of the obtained InP / ZnSeS / ZnS core-shell quantum dots, with an emission peak of 540 nm, showing green light, a half-peak width of 47 nm, and a quantum yield of 70.93%. Figure 8 : is a transmission electron microscope (TEM) image of the obtained InP / ZnSeS / ZnS core-shell quantum dots, and the core-shell quantum dots have good dispersion. Fig.10 (b) is a photograph of the dispersion of the obtained InP / ZnSeS / ZnS core-shell quantum dots under 365nm sunlight excitation light. It can be seen that the prepared core-shell quantum dots exhibit bright fluorescence.

[0129] Example 3

[0130] Example 1 was repeated, except that the zinc precursor was replaced with 3 g of zinc chloride, and the rest of the reaction process and conditions remained unchanged.

[0131] Figure 4The emission spectrum of the obtained InP / ZnSeS / ZnS core-shell quantum dots has an emission peak of 577nm, yellow light, a half-peak width of 44nm, and a quantum yield of 62.25%.

[0132] Fig. 9 is a transmission electron microscope (TEM) image of the obtained InP / ZnSeS / ZnS core-shell quantum dots, which have good dispersion;

[0133] Fig.10 (c) is a photograph of the dispersion of the obtained InP / ZnSeS / ZnS core-shell quantum dots under 365nm sunlight excitation light. It can be seen that the prepared core-shell quantum dots exhibit bright fluorescence.

[0134] Example 4

[0135] Example 1 was repeated, except that the rotation speed of the high gravity rotating packed bed reactor was set to 0 rpm, 500 rpm, 1000 rpm, 1500 rpm, and 2000 rpm, and the other reaction processes and conditions remained unchanged.

[0136] Fig.11 is the emission spectrum of the obtained InP / ZnSeS / ZnS core-shell quantum dots. Fig.12 This is a comparison chart of the half-peak width and quantum yield of the obtained InP / ZnSeS / ZnS core-shell quantum dots.

[0137] Comparative Example 1

[0138] Replace the indium precursor and zinc precursor with 1g indium chloride and 3g zinc chloride, and use the supergravity device that is not currently coupled to the photothermal device to prepare InP / ZnS quantum dots. The steps are as follows:

[0139] InP / ZnS quantum dots were synthesized in a supergravity reactor without a coupled photothermal device. The motor was started and the speed was set to 1500 r / min. The InP core Zn precursor mixed oil phase precursor and sodium sulfide nonahydrate aqueous phase precursor were preheated respectively, and then introduced into the supergravity device through a peristaltic pump. The heat from the preheating of the precursors was used to fully react under supergravity conditions for 30 minutes. Samples were taken at regular intervals and their luminescence properties were tested.

[0140] Fig.13 This is the emission spectrum of the obtained InP / ZnS core-shell quantum dots, with an emission peak of 613 nm, orange light, a half-peak width of 88 nm, and a quantum yield of 7.38%.

[0141] Comparative Example 2

[0142] Example 1 was repeated, except that the rotation speed of the high gravity rotating packed bed reactor was set to 500 rpm, samples were taken at different time points during the reaction, and the other reaction processes and conditions remained unchanged.

[0143] Fig.14 The graph of the quantum yield of the obtained InP / ZnSeS / ZnS core-shell quantum dots changing with time shows that the quantum dots have the highest quantum yield when the reaction time is 30 minutes.

[0144] Comparative Example 3

[0145] Example 1 was repeated, except that the rotation speed of the high gravity rotating packed bed reactor was set to 500 rpm, and the ratio of selenium powder to sulfur powder was changed from 0:1 to 2:1.

[0146] Fig.15 The fluorescence spectrum of the obtained InP / ZnSeS / ZnS core-shell quantum dots is as follows. When the ratio is 0.5:1, the obtained InP / ZnSeS / ZnS core-shell quantum dots have the highest quantum yield of 79.86% and the narrowest half-peak width of 58nm.

[0147] Comparative Example 4

[0148] Example 1 was repeated, except that the molar ratio of indium ions in the indium precursor to the phosphine precursor was changed from 1:3 to 1:7 to synthesize only InP cores.

[0149] Fig.16 The UV-visible absorption spectrum of the obtained InP quantum dots is shown in Figure 2. With the increase of phosphine precursor, the first exciton peak of quantum dots becomes less and less obvious, indicating that the size uniformity becomes worse.

[0150] Comparative Example 5

[0151] Example 1 was repeated, except that the molar ratio of indium ions in the indium precursor to the phosphine precursor was 1:2 to synthesize only InP cores.

[0152] The color of the solution obtained at this time is very light, indicating that the content of phosphine precursor is too low, making nucleation difficult.

[0153] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all implementation methods here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A reaction device for narrow-band luminescent indium phosphide quantum dots, characterized in that: Includes supergravity device and photothermal device; The supergravity device comprises a housing, a motor, a rotating disk, a shear filler, a liquid distributor, a reaction chamber, a filler cover, a gas outlet, a liquid outlet, and a liquid inlet; The output shaft of the motor passes through the lower surface of the housing and extends into the housing to be fixedly connected to the turntable; at the same time, the top end of the output shaft of the motor is also fixedly connected to a liquid distributor located above the turntable; An annular shear filler is arranged on the rotating disk, and the top of the shear filler is fixedly covered with a filler cover; a hollow reaction chamber is formed between the rotating disk, the shear filler and the filler cover; A liquid outlet is provided on the bottom of the shell; the liquid inlet passes through the shell and is connected to the packing cover and the reaction chamber; a gas outlet is provided on the top of the shell; The photothermal device includes a laser heating device, a circuit and a water cooling device, a reflective layer and a laser controller; The reflective layer is arranged on the inner surface of the shell, and an interlayer is arranged between the reflective layer and the shell, and a circuit and a water cooling device are arranged in the interlayer; the laser heating device is arranged on the inner surface of the reflective layer, and the laser heating device is connected to the laser controller through the circuit in the interlayer.

2. The reaction device of narrow-band luminescent indium phosphide quantum dots according to claim 1, characterized in that: The filler cover is made of a transparent material to allow the laser to pass through as much as possible; Preferably, the laser heating device includes one or more devices, which can be installed or removed as needed; Preferably, the laser heating device is a laser with a wavelength of 980-1500nm; Preferably, the power of the laser heating device is 20-500W.

3. A method for producing narrow-band luminescent indium phosphide quantum dots using the reaction device described in any one of claims 1 or 2, characterized in that: The steps include: 1) dissolving an indium precursor, a zinc precursor, and a phosphine precursor in an organic solvent respectively, and then introducing them into a supergravity reactor to react at a temperature of 110-130° C. to obtain an InP quantum dot core; 2) dissolving zinc salt, sulfur powder and selenium powder in an organic solvent, and then introducing the mixture into the supergravity reactor of the InP quantum dot core to react, thereby obtaining InP / ZnSeS core-shell quantum dots; 3) introducing the zinc salt and the thiol into the above-mentioned InP / ZnSeS core-shell quantum dots to react, and obtaining a reaction mixture I; 4) Adding a poor solvent to the reaction mixture after the shell coating is completed and centrifuging it to obtain a precipitate which is narrow-band luminescent indium phosphide quantum dots.

4. The method for producing narrow-band luminescent indium phosphide quantum dots according to claim 3, characterized in that: In step 1), the indium precursor is one of indium iodide, indium bromide and indium chloride.

5. The method for producing narrow-band luminescent indium phosphide quantum dots according to claim 3, characterized in that: In step 1), the zinc precursor is one of zinc iodide, zinc bromide and zinc chloride; Preferably, in step 1), the phosphine precursor is tris(dimethylamino)phosphine or tris(diethylamino)phosphine; Preferably, in step 1), the organic solvent is one or more of oleylamine, octadecylamine, hexadecylamine, tetradecylamine and dodecylamine.

6. The method for producing narrow-band luminescent indium phosphide quantum dots according to claim 3, characterized in that: In step 1), the molar ratio of indium ions in the indium precursor to zinc ions in the zinc precursor is 1:1-1:10; Preferably, in step 1), the molar ratio of indium ions in the indium precursor to the phosphine precursor is 1:3-1:7; Preferably, in step 1), the molar ratio of the indium precursor to the organic solvent is 1:20-1:

100.

7. The method for producing narrow-band luminescent indium phosphide quantum dots according to claim 3, characterized in that: In step 2), the zinc salt is one or more of zinc iodide, zinc bromide, zinc chloride, zinc stearate, zinc oleate, and zinc acetate; Preferably, in step 2), the organic solvent is one of oleylamine, 1-octadecene, tri-n-octylphosphine and tri-n-octylphosphine oxide.

8. The method for producing narrow-band luminescent indium phosphide quantum dots according to claim 3, characterized in that: In step 1 and step 2), the molar ratio of indium ions in the indium precursor to the zinc salt is 1:3-1:10; Preferably, in step 1 and step 2), the ratio of the sum of the molar numbers of indium ions in the indium precursor and the sulfur powder and selenium powder is 1:3-1:10; Preferably, in step 1) and step 2), the high gravity reactor is a high gravity rotating packed bed reactor; the rotation speed of the high gravity rotating packed bed reactor is 500 rpm-2000 rpm, and the reaction time is 1 s-60 min.

9. The method for producing narrow-band luminescent indium phosphide quantum dots according to claim 3, characterized in that: In step 3), the mercaptan is one of dodecyl mercaptan, hexadecyl mercaptan and octyl mercaptan; Preferably, in step 1) and step 3), the molar ratio of indium ions to the thiol in the indium precursor is 1:10-1:

20.

10. The method for producing narrow-band luminescent indium phosphide quantum dots according to claim 3, characterized in that: In step 4), the poor solvent is ethanol or acetone.

Images