CN111303882A - Cadmium-free quantum dot and preparation method thereof - Google Patents
Cadmium-free quantum dot and preparation method thereof Download PDFInfo
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Abstract
The invention provides a cadmium-free quantum dot and a preparation method thereof. The preparation method comprises the following steps: s1, mixing the first precursor, the first ligand and the solvent, and heating to a first temperature to obtain a first mixed solution; s2, mixing a second precursor, a second ligand and a solvent, and adding the first mixed solution at a second temperature to prepare a second mixed solution; s3, heating the second mixed solution for a first time length to a third temperature, and keeping the temperature at the third temperature for a second time length; and S4, heating the mixture for the third time to the fourth temperature, and keeping the temperature at the fourth temperature for the fourth time to obtain the quantum dot core. According to the method, the nucleation and growth uniformity of the quantum dots are controlled by the multi-gradient heating technology, the half-peak width of the cadmium-free quantum dot core and the half-peak width of the quantum dots are reduced, and the light efficiency of the cadmium-free quantum dots is improved.
Description
Technical Field
The invention relates to the technical field of semiconductors, in particular to a cadmium-free quantum dot and a preparation method thereof.
Background
The quantum dots are also called semiconductor nanocrystals, and have the advantages of adjustable light-emitting wavelength, high light-emitting efficiency, good stability and the like, so that the quantum dots are widely applied to the fields of display, illumination, biology, solar cells and the like. In recent years, research on II-VI group quantum dot materials containing CdSe, CdS and the like has been greatly advanced, the performances of the materials such as luminous efficiency, half-peak width, stability and the like are greatly improved, and the materials are applied to the fields of display, biology and the like. However, since Cd is a toxic heavy metal, the european union "legislation on chemical registration, evaluation, permission and restriction" (REACH for short) strictly regulates the Cd content in goods entering the market, and its wide application is limited, so people never give up on research on environment-friendly cadmium-free quantum dots. How to improve the performance of the cadmium-free quantum dots is always the key point and the difficulty of research. In cadmium-free quantum dots, III-V group InP-based quantum dots become a research hotspot and are expected to replace Cd-containing quantum dots.
In recent years, the development of cadmium-free quantum dots has also made great progress, and the cadmium-free quantum dots are commercially applied at present. However, the performance ratio of the quantum dots containing cadmium is different, and the difference is mainly reflected in the aspects of wide half-peak width, low luminous efficiency and the like. At present, the preparation methods of the quantum dot core mainly comprise two methods: one is a hot injection method (hot injection) and one is a heating method (heating up). The thermal injection method is a method in which one precursor is heated to a certain temperature and then another precursor is injected at a high temperature to form a quantum dot core. This method can separate nucleation and growth, but cannot be easily scaled up for production. The heating method is a method in which two or more reaction precursors are mixed and then directly heated to a set temperature to generate a quantum dot core. The method is simple to operate and suitable for large-scale production, but cannot separate nucleation from growth, and quantum dots with higher quality can be obtained only at a relatively proper rate of nucleation and growth. Therefore, developing a new preparation technology, reducing the half-peak width of the cadmium-free quantum dot and improving the fluorescence efficiency of the cadmium-free quantum dot has important significance.
Disclosure of Invention
The invention mainly aims to provide a cadmium-free quantum dot and a preparation method thereof, and aims to solve the problems that the cadmium-free quantum dot in the prior art is low in luminous efficiency and large in luminous half-peak width.
In order to achieve the above object, according to an aspect of the present invention, there is provided a method for preparing a cadmium-free quantum dot, including the steps of: s1, mixing the first precursor, the first ligand and the solvent, and heating to a first temperature to obtain a first mixed solution; s2, mixing a second precursor, a second ligand and a solvent, and adding the first mixed solution at a second temperature to prepare a second mixed solution; s3, heating the second mixed solution for a first time length to a third temperature, and keeping the temperature at the third temperature for a second time length; and S4, heating the mixture for a third time to a fourth temperature, and keeping the temperature at the fourth temperature for the fourth time to obtain the quantum dot core.
Further, the heating rate of the heating reaction in the step S3 and the step S4 is independently selected from 1 to 150 ℃/min, preferably 5 to 100 ℃/min.
Further, the third temperature and the fourth temperature are respectively 30 to 310 ℃, and the fourth temperature is higher than the third temperature.
Further, the second time period and the fourth time period are 1min to 2h, respectively.
Further, the heating process in the above step S3 may be a gradient heating process, preferably, a multi-gradient heating process.
Further, the step S3 includes the following steps: s31, heating the second mixed solution for a fifth time length to a fifth temperature, and keeping the temperature at the fifth temperature for a sixth time length; s32, repeating the operation of the step S31 one to three times to obtain the second mixed solution with the final temperature of the third temperature; wherein the heating rate of the heating reaction in the step S31 is the same as or different from that in the step S32, and the time length of the isothermal reaction in the step S31 is the same as or different from that in the step S32.
Further, the third temperature is not higher than 150 ℃, the temperature rising rate of the heating reaction in the step S3 is independently selected from 5 to 75 ℃/min, and the temperature rising rate of the heating reaction in the step S4 is selected from 50 to 100 ℃/min.
Further, the molar ratio of the first precursor to the second precursor is 50:1 to 1:50, preferably 10:1 to 1: 10.
Further, the first precursor is a group iii element precursor, and the second precursor is a group v element precursor.
Further, the first precursor may be selected from one or more of Zn, Mg, Ca, Sr, Al, Zr, Fe, Sc, Ti, Cr, Si, and Ni element precursors.
Further, after the step S4, the method further includes a step S5 of coating a shell layer on the quantum dot core.
According to another aspect of the invention, the cadmium-free quantum dot is prepared by adopting the preparation method.
According to another aspect of the invention, a photoelectric device is also provided, which comprises the cadmium-free quantum dot prepared by the preparation method.
The technical scheme of the invention provides a preparation method of cadmium-free quantum dots, and the method controls the nucleation and growth uniformity of the quantum dots by a multi-gradient heating technology, reduces the half-peak width of cadmium-free quantum dot nuclei and the half-peak width of the quantum dots, and improves the light efficiency of the cadmium-free quantum dots.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:
fig. 1 is a schematic flow chart illustrating a method for preparing cadmium-free quantum dots according to the present invention;
fig. 2 shows a uv-vis absorption spectrum of an InP quantum dot core in example 1 of the present application.
Detailed Description
It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged under appropriate circumstances in order to facilitate the description of the embodiments of the invention herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
As described in the background, the quantum dot without cadmium in the prior art has low light efficiency and large half-width of light emission. In order to solve the above technical problems, the present invention provides a method for preparing cadmium-free quantum dots, as shown in fig. 1, comprising the following steps: s1, mixing the first precursor, the first ligand and the solvent, and heating to a first temperature to obtain a first mixed solution; s2, mixing a second precursor, a second ligand and a solvent, and adding the first mixed solution at a second temperature to prepare a second mixed solution; s3, heating the second mixed solution for a first time length to a third temperature, and keeping the temperature at the third temperature for a second time length; and S4, heating the mixture for the third time to the fourth temperature, and keeping the temperature at the fourth temperature for the fourth time to obtain the quantum dot core.
Step S1, mixing the first precursor, the first ligand and the solvent, heating to a first temperature, and dissolving the first precursor and the first ligand in the solvent to form a first mixed solution. Wherein the first ligand is selected from one or more of caprylic acid, decadic acid, dodecanoic acid, hexadecanoic acid, octadecanoic acid and oleic acid, but is not limited thereto.
Step S2, mixing the second precursor, the second ligand, and the solvent, and adding the first mixed solution at a second temperature to prepare a second mixed solution. Wherein the second ligand is selected from phosphine ligands (such as trioctylphosphine and tributylphosphine) and/or amine ligands (such as n-hexylamine, octamine, dodecylamine, dipropylamine and trioctylamine), but is not limited thereto. It will be understood by those skilled in the art that the first temperature in step S1 may be controlled within a range that the first precursor and the first ligand are sufficiently dissolved in the solvent, and the first mixed solution may be cooled naturally or physically (for example, by using cold oil) to the second temperature after being formed. In some embodiments, the second temperature is not higher than the first temperature, preferably the second temperature is room temperature.
Step S3, heating the second mixed solution for a first time length to a third temperature, and keeping the temperature at the third temperature for a second time length; and step S4, heating the mixture for a third time to a fourth temperature, and keeping the temperature at the fourth temperature for the fourth time to obtain the quantum dot core.
The preparation method of the cadmium-free quantum dot, which is adopted by the invention, controls the nucleation and growth uniformity of the quantum dot by a multi-gradient heating technology, reduces the half-peak width of the cadmium-free quantum dot nucleus and the half-peak width of the quantum dot, and improves the light efficiency of the cadmium-free quantum dot.
In one or more embodiments, the heating rate of the heating reaction in step S3 and step S4 is independently selected from 1 to 150 deg.C/min, preferably 5 to 100 deg.C/min.
In one or more embodiments, the third temperature and the fourth temperature are 30 to 310 ℃ in step S3 and step S4, respectively, and it is understood that the fourth temperature is higher than the third temperature.
In one or more embodiments, the second time length and the fourth time length are respectively 1min to 2h, and the second time length may be greater than, equal to, or less than the fourth time length.
In one or more embodiments, the heating process in step S3 is a gradient heating process, that is, the second mixed solution is heated from the second temperature to a certain temperature and then is kept at the constant temperature for a certain period of time, the second mixed solution is heated to the certain temperature again and then is kept at the constant temperature for a certain period of time, and after the heating and keeping at the constant temperature are performed for a plurality of times, the second mixed solution reaches the third temperature, and is kept at the third temperature for a second period of time. The temperature rise rate of each temperature rise in the heating process is independently selected from 1-150 ℃/min, preferably 5-100 ℃/min, and more preferably 5-75 ℃/min. The rate of each temperature rise may be the same or different. When the temperature rise rates of the plurality of times of temperature rise are different, the heating process in step S3 is a multi-gradient heating process. The constant temperature time length of each time in the heating process is 1 min-2 h, and the constant temperature time length can be the same or different according to specific quantum dots.
In a preferred embodiment, step S3 includes the steps of: s31, heating the second mixed solution for a fifth time to a fifth temperature, and keeping the temperature at the fifth temperature for a sixth time; s32, repeating the operation of the step S31 for one to three times to obtain a second mixed solution with the final temperature being a third temperature; wherein the heating rate of the heating reaction in step S31 is the same as or different from that in step S32, and the time length of the isothermal reaction in step S31 is the same as or different from that in step S32.
In a more preferred embodiment, the third temperature is not higher than 150 ℃, the heating rate of the heating reaction in the step S3 is independently selected from 5 to 75 ℃/min, and the heating rate of the heating reaction in the step S4 is selected from 50 to 100 ℃/min, wherein the step S4 is a direct rapid heating process, and when the temperature of the second mixed solution is increased to the third temperature, then the increase of the heating rate in the heating reaction of the step S4 helps to form a uniform quantum dot core.
In the prior art, phosphorus precursors (e.g., P (SiMe)) are commonly used for the preparation of InP quantum dots3)3) Is too high and the reaction time at high temperature is only a few seconds, which results in insufficient supply of P monomer during the growth phase, so that the growth of InP quantum dots enters the Ostwald ripening phase prematurely, resulting in polydispersity of the quantum dot size. The preparation method of the cadmium-free quantum dot reduces the half-peak width of the cadmium-free quantum dot core and the half-peak width of the quantum dot and improves the light efficiency of the cadmium-free quantum dot by controlling the nucleation and growth uniformity of the quantum dot by a multi-gradient heating technology.
In the above preparation method of the present invention, the molar ratio of the first precursor to the second precursor is preferably 50:1 to 1:50, and more preferably 10:1 to 1: 10.
In one or more embodiments, the first precursor is a group iii element precursor and the second precursor is a group v element precursor, forming a group iii-v quantum dot; preferably, the group iii-v quantum dots are InP quantum dots, InAs quantum dots, doped InP quantum dots, or doped InAs quantum dots, but are not limited thereto.
In one or more embodiments, the first precursor is selected from one or more of Zn, Mg, Ca, Sr, Al, Zr, Fe, Sc, Ti, Cr, Si, and Ni elemental precursors.
In a preferred embodiment, after the step S4, the preparation method of the present invention further includes a step S5 of cladding a shell layer on the quantum dot core; preferably, the shell layer is a II-VI compound shell layer, and the shell layer can improve the stability of the cadmium-free quantum dot. In one or more embodiments, the quantum dot core is coated with two II-VI compound shell layers, so that the stability of the cadmium-free quantum dot is greatly improved, wherein the first shell layer and the second shell layer are the same or different in types. The first shell layer or the second shell layer may comprise a plurality of single shell layers.
After the above step S4, the reaction system is heated or cooled to the initial reaction temperature of step S5. In some embodiments, the initial reaction temperature of step S5 is 100-310 ℃.
According to another aspect of the application, a cadmium-free quantum dot is provided, and the cadmium-free quantum dot is prepared by adopting the preparation method. The preparation method controls the nucleation and growth uniformity of the quantum dots by a multi-gradient heating technology, reduces the half-peak width of the cadmium-free quantum dot core and the half-peak width of the quantum dots, and improves the light efficiency of the cadmium-free quantum dots.
The cadmium-free quantum dot provided by the application can be applied to preparing a quantum dot composition, and the composition comprises the cadmium-free quantum dot prepared by the preparation method. When the composition is used for specific application, the composition also has the application advantages because the cadmium-free quantum dots not only have narrower half-peak width, but also have higher luminous efficiency.
According to another aspect of the present application, there is provided an optoelectronic device comprising cadmium-free quantum dots as electroluminescent material or photoluminescent material. Specifically, the photoelectric device may be an electroluminescent display device, a photoluminescent display device, an image sensor, or a solar cell, but is not limited thereto.
The present invention is described in further detail below with reference to specific examples, which are not to be construed as limiting the scope of the invention as claimed.
[ example 1 ]
The preparation method of the embodiment comprises the following steps:
first, 0.2mmol of In (Ac) was weighed3(indium acetate), 0.6mmol of OA (oleic acid), 5.0g of ODE (octadecene) were charged in a 100mL three-necked flask, and N2Heating to 170 ℃ in an exhaust state to dissolve, and then cooling to room temperature.
Then, a mixture of 0.1mmol TMS-P (tris (trimethylsilyl) phosphine), 0.5mL TOP, and 0.5mL ODE (octadecene) was added to the above solution at room temperature.
Then, heating from room temperature (25 ℃) to 150 ℃ for 5min, and keeping the constant temperature for 2 min; heating to 300 ℃ for 5min, and reacting for 2min at constant temperature to obtain the InP nuclear solution.
Finally, the reaction temperature is reduced to 150 ℃, and 1.5mmol ZnAc is added2(Zinc acetate), exhausting gas for 30min, heating to 280 ℃, adding 1mL of Se-TOP (0.1mmol/mL) (selenium-trioctylphosphine) for reaction for 20min, adding 0.8mL of S-TOP (1mmol/mL) (sulfur-trioctylphosphine) for reaction for 20 min. And after the reaction is finished, cooling to room temperature, extracting for three times by using methanol, precipitating and centrifuging by using acetone, and dissolving the precipitate in toluene to obtain an InP/ZnSe/ZnS quantum dot solution.
[ example 2 ]
The preparation method of the embodiment comprises the following steps:
first, 0.2mmol of In (Ac) was weighed3(indium acetate), 0.6mmol of OA (oleic acid), 5.0g of ODE (octadecene) were charged in a 100mL three-necked flask, and N2Heating to 170 ℃ in an exhaust state to dissolve, and then cooling to room temperature.
Then, a mixture of 0.1mmol TMS-P (tris (trimethylsilyl) phosphine), 0.5mL TOP, and 0.5mL ODE (octadecene) was added to the above solution at room temperature.
Then, heating to 85 ℃ from room temperature for 10min, and keeping the constant temperature for 5 min; heating to 150 deg.C for 10min, heating to 300 deg.C for 5min, and reacting at constant temperature for 2min to obtain InP core solution.
Finally, the reaction temperature is reduced to 150 ℃, and 1.5mmol ZnAc is added2(Zinc acetate), exhausting gas for 30min, heating to 280 ℃, adding 1mL of Se-TOP (0.1mmol/mL) (selenium-trioctylphosphine) for reaction for 20min, adding 0.8mL of S-TOP (1mmol/mL) (sulfur-trioctylphosphine) for reaction for 20 min. And after the reaction is finished, cooling to room temperature, extracting for three times by using methanol, precipitating and centrifuging by using acetone, and dissolving the precipitate in toluene to obtain an InP/ZnSe/ZnS quantum dot solution.
[ example 3 ]
The preparation method of the embodiment comprises the following steps:
first, 0.2mmol of In (Ac) was weighed3(indium acetate), 0.6mmol of OA (oleic acid), 5.0g of ODE (octadecene) were charged in a 100mL three-necked flask, and N2Heating to 170 ℃ in an exhaust state to dissolve, and then cooling to room temperature.
Then, a mixture of 0.1mmol TMS-P (tris (trimethylsilyl) phosphine), 0.5mL TOP, and 0.5mL ODE (octadecene) was added to the above solution at room temperature.
Then, heating the mixture from room temperature for 5min to 50 ℃ at the speed of 5 ℃/min, and keeping the constant temperature for 5 min; heating to 75 deg.C at 5 deg.C/min for 5min, and holding the temperature for 5 min; heating to 125 deg.C at a rate of 10 deg.C/min for 5min, and holding the temperature for 2 min; heating to 300 ℃ for 5min, and reacting for 2min at constant temperature to obtain the InP nuclear solution.
Finally, the reaction temperature is reduced to 150 ℃, and 1.5mmol ZnAc is added2(Zinc acetate), exhausting gas for 30min, heating to 280 ℃, adding 1mL of Se-TOP (0.1mmol/mL) (selenium-trioctylphosphine) for reaction for 20min, adding 0.8mL of S-TOP (1mmol/mL) (sulfur-trioctylphosphine) for reaction for 20 min. And after the reaction is finished, cooling to room temperature, extracting for three times by using methanol, precipitating and centrifuging by using acetone, and dissolving the precipitate in toluene to obtain an InP/ZnSe/ZnS quantum dot solution.
[ example 4 ]
The preparation method of the embodiment comprises the following steps:
first, 0.2mmol of In (Ac) was weighed3(indium acetate), 0.6mmol of OA (oleic acid), 5.0g of ODE (octadecene) were charged in a 100mL three-necked flask, and N2Heating to 170 ℃ in an exhaust state to dissolve, and then cooling to room temperature.
Then, a mixture of 0.1mmol TMS-P (tris (trimethylsilyl) phosphine), 0.5mL TOP, and 0.5mL ODE (octadecene) was added to the above solution at room temperature.
Then, heating the mixture from room temperature for 2min to 125 ℃ at the speed of 50 ℃/min, and keeping the constant temperature for 5 min; heating to 285 ℃ at the speed of 80 ℃/min for 2min to obtain the InP nuclear solution.
Finally, the reaction temperature is reduced to 150 ℃, and 1.5mmol ZnAc is added2(Zinc acetate), exhausting gas for 30min, heating to 280 ℃, adding 1mL of Se-TOP (0.1mmol/mL) (selenium-trioctylphosphine) for reaction for 20min, adding 0.8mL of S-TOP (1mmol/mL) (sulfur-trioctylphosphine) for reaction for 20 min. And after the reaction is finished, cooling to room temperature, extracting for three times by using methanol, precipitating and centrifuging by using acetone, and dissolving the precipitate in toluene to obtain an InP/ZnSe/ZnS quantum dot solution.
[ example 5 ]
The preparation method of the embodiment comprises the following steps:
first, 0.2mmol of In (Ac) was weighed3(indium acetate), 0.6mmol of OA (oleic acid), 5.0g of ODE (octadecene) were charged in a 100mL three-necked flask, and N2Heating to 170 ℃ in an exhaust state to dissolve, and then cooling to room temperature.
Then, a mixture of 0.1mmol TMS-P (tris (trimethylsilyl) phosphine), 0.5mL TOP, and 0.5mL ODE (octadecene) was added to the above solution at room temperature.
Then, heating the mixture from room temperature for 5min to 30 ℃ at the speed of 1 ℃/min, and keeping the constant temperature for 5 min; heating to 150 deg.C for 10min, and maintaining the constant temperature for 3 min; heating to 300 ℃ at the speed of 20 ℃/min for 5min, and reacting at constant temperature for 2min to obtain the InP nuclear solution.
Finally, the reaction temperature is reduced to 150 ℃, and 1.5mmol ZnAc is added2(Zinc acetate), exhausting gas for 30min, heating to 280 deg.C, adding 1mL Se-TOP (0.1mmol/mL) (selenium-trioctylphosphine) for reaction for 20min, adding 0.8mL S-TOP (1mmol/mL) (sulfur-trioctylphosphine), and reactingAnd 20 min. And after the reaction is finished, cooling to room temperature, extracting for three times by using methanol, precipitating and centrifuging by using acetone, and dissolving the precipitate in toluene to obtain an InP/ZnSe/ZnS quantum dot solution.
[ example 6 ]
The preparation method of the embodiment comprises the following steps:
first, 0.2mmol of In (Ac) was weighed3(indium acetate), 0.6mmol of OA (oleic acid), 5.0g of ODE (octadecene) were charged in a 100mL three-necked flask, and N2Heating to 170 ℃ in an exhaust state to dissolve, and then cooling to room temperature.
Then, a mixture of 0.1mmol TMS-P (tris (trimethylsilyl) phosphine), 0.5mL TOP, and 0.5mL ODE (octadecene) was added to the above solution at room temperature.
Then, heating the mixture from room temperature for 5min to 100 ℃ at the speed of 15 ℃/min, and keeping the constant temperature for 10 min; heating to 300 ℃ at the speed of 100 ℃/min for 2min, and reacting at constant temperature for 5min to obtain the InP nuclear solution.
Finally, the reaction temperature is reduced to 150 ℃, and 1.5mmol ZnAc is added2(Zinc acetate), exhausting gas for 30min, heating to 280 ℃, adding 1mL of Se-TOP (0.1mmol/mL) (selenium-trioctylphosphine) for reaction for 20min, adding 0.8mL of S-TOP (1mmol/mL) (sulfur-trioctylphosphine) for reaction for 20 min. And after the reaction is finished, cooling to room temperature, extracting for three times by using methanol, precipitating and centrifuging by using acetone, and dissolving the precipitate in toluene to obtain an InP/ZnSe/ZnS quantum dot solution.
[ example 7 ]
The preparation method of the embodiment comprises the following steps:
first, 0.2mmol of In (Ac) was weighed3(indium acetate), 0.6mmol of OA (oleic acid), 5.0g of ODE (octadecene) were charged in a 100mL three-necked flask, and N2Heating to 170 ℃ in an exhaust state to dissolve, and then cooling to room temperature.
Then, a mixture of 0.1mmol TMS-P (tris (trimethylsilyl) phosphine), 0.5mL TOP, and 0.5mL ODE (octadecene) was added to the above solution at room temperature.
Then, heating the mixture from room temperature for 5min to 150 ℃ at the speed of 25 ℃/min, and keeping the constant temperature for 10 min; and then heating to 300 ℃ at the speed of 150 ℃/min for 1min, and reacting for 2h at constant temperature to obtain the InP nuclear solution.
Finally, the reaction temperature is reduced to 150 ℃, and 1.5mmol ZnAc is added2(Zinc acetate), exhausting gas for 30min, heating to 280 ℃, adding 1mL of Se-TOP (0.1mmol/mL) (selenium-trioctylphosphine) for reaction for 20min, adding 0.8mL of S-TOP (1mmol/mL) (sulfur-trioctylphosphine) for reaction for 20 min. And after the reaction is finished, cooling to room temperature, extracting for three times by using methanol, precipitating and centrifuging by using acetone, and dissolving the precipitate in toluene to obtain an InP/ZnSe/ZnS quantum dot solution.
[ example 8 ]
The preparation method of the embodiment is different from that of the embodiment 1 in that:
In(Ac)3the dosage of the (indium acetate) is 0.2mmol, and the dosage of the TMS-P (tri (trimethylsilyl) phosphine) is 0.02 mmol.
[ example 9 ]
The preparation method of the embodiment is different from that of the embodiment 1 in that:
In(Ac)3the dosage of (indium acetate) is 0.2mmol, and the dosage of TMS-P (tris (trimethylsilyl) phosphine) is 2 mmol.
Comparative example 1
The preparation method of the thermal injection method comprises the following steps:
0.2mmol of In (Ac) was weighed3(indium acetate), 0.6mmol of OA (oleic acid), 5.0g of ODE (octadecene) were charged in a 100mL three-necked flask, and N2Heating to 280 ℃ under the exhaust state and keeping the temperature constant. And (3) quickly injecting a mixed solution of 0.1mmol of TMS-P (tri (trimethylsilyl) phosphine), 0.5mL of TOP and 0.5mL of ODE (octadecene), and reacting for 10min to obtain an InP nuclear solution.
The reaction temperature is reduced to 150 ℃, and 1.5mmol of ZnAc is added2(Zinc acetate), exhausting gas for 30min, heating to 280 ℃, adding 1mL of Se-TOP (0.1mmol/mL) (selenium-trioctylphosphine) for reaction for 20min, adding 0.8mL of S-TOP (1mmol/mL) (sulfur-trioctylphosphine) for reaction for 20 min. And after the reaction is finished, cooling to room temperature, extracting for three times by using methanol, precipitating and centrifuging by using acetone, and dissolving the precipitate in toluene to obtain an InP/ZnSe/ZnS quantum dot solution.
Comparative example 2
The preparation method by the heating method comprises the following steps:
0.2mmol of In (Ac) was weighed3(indium acetate), 0.6mmol of OA (oleic acid), 5.0g of ODE (octadecene) were charged in a 100mL three-necked flask, and N2Heating to 170 ℃ in an exhaust state to dissolve, and then cooling to room temperature. And adding a mixed solution of 0.1mmol of TMS-P (tri (trimethylsilyl) phosphine), 0.5mL of TOP and 0.5mL of ODE (octadecene) into the solution, directly heating to 280 ℃, and reacting at constant temperature for 10min to obtain an InP core solution.
The reaction temperature is reduced to 150 ℃, and 1.5mmol of ZnAc is added2(Zinc acetate), exhausting gas for 30min, heating to 280 ℃, adding 1mL of Se-TOP (0.1mmol/mL) (selenium-trioctylphosphine) for reaction for 20min, then adding 0.8mL of S-TOP (1mmol/mL) (sulfur-trioctylphosphine) for reaction for 20 min. And after the reaction is finished, cooling to room temperature, extracting for three times by using methanol, precipitating and centrifuging by using acetone, and dissolving the precipitate in toluene to obtain an InP/ZnSe/ZnS quantum dot solution.
Ultraviolet absorption tests were performed on the InP core solutions prepared in examples 1 to 9 and comparative examples 1 and 2 to obtain half-peak width of the ultraviolet absorption peak of the InP core; the fluorescence emission performance of the InP/ZnSe/ZnS quantum dot solution was tested to obtain the Photoluminescence (PL) spectral emission peak position and emission peak half-peak width of the InP/ZnSe/ZnS quantum dots, and the quantum yield of the InP/ZnSe/ZnS quantum dots was tested with an integrating sphere, the results of which are shown in Table 1.
TABLE 1
The synthesis quality of the nuclei can be judged according to the data of the half-peak width of the InP nuclei, and the narrower the half-peak width is, the better the uniformity of the nuclei is. Comparing examples 1-9 with comparative examples 1 and 2, it can be seen that the cadmium-free quantum dot core produced by the preparation method of the present invention has better uniformity, the obtained cadmium-free quantum dot has relatively narrow half-peak width, and the quantum efficiency is also greatly improved.
From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:
the preparation method controls the nucleation and growth uniformity of the quantum dots by a multi-gradient heating technology, reduces the half-peak width of the cadmium-free quantum dot core and the half-peak width of the quantum dots, and improves the light efficiency of the cadmium-free quantum dots.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (13)
1. A preparation method of cadmium-free quantum dots is characterized by comprising the following steps:
s1, mixing the first precursor, the first ligand and the solvent, and heating to a first temperature to obtain a first mixed solution;
s2, mixing a second precursor, a second ligand and a solvent, and adding the first mixed solution at a second temperature to prepare a second mixed solution;
s3, heating the second mixed solution for a first time length to a third temperature, and keeping the temperature at the third temperature for a second time length;
and S4, heating for a third time to a fourth temperature, and keeping the temperature at the fourth temperature for a fourth time to obtain the quantum dot core.
2. The method for preparing the cadmium-free quantum dot according to claim 1, wherein the temperature rise rate of the heating reaction in the steps S3 and S4 is independently selected from 1 to 150 ℃/min, preferably 5 to 100 ℃/min.
3. The method for preparing the cadmium-free quantum dot according to claim 2, wherein the third temperature and the fourth temperature are respectively 30-310 ℃, and the fourth temperature is higher than the third temperature.
4. The method according to claim 1, wherein the second time period and the fourth time period are 1min to 2h, respectively.
5. The method for preparing cadmium-free quantum dots according to claim 3, wherein the heating process in the step S3 is a gradient heating process, preferably a multi-gradient heating process.
6. The method for preparing the cadmium-free quantum dot according to claim 5, wherein the step S3 comprises the following steps:
s31, heating the second mixed solution for a fifth time length to a fifth temperature, and keeping the temperature at the fifth temperature for a sixth time length;
s32, repeating the operation of the step S31 for one to three times to obtain the second mixed solution with the final temperature being the third temperature;
wherein the heating reaction in the step S31 has the same or different temperature rise rate as that in the step S32, and the isothermal reaction in the step S31 has the same or different time length as that in the step S32.
7. The method of claim 6, wherein the third temperature is not higher than 150 ℃, the temperature rise rate of the heating reaction in the step S3 is independently selected from 5 to 75 ℃/min, and the temperature rise rate of the heating reaction in the step S4 is selected from 50 to 100 ℃/min.
8. The method for preparing the cadmium-free quantum dot according to claim 1, wherein the molar ratio of the first precursor to the second precursor is 50: 1-1: 50, preferably 10: 1-1: 10.
9. The method of claim 1, wherein the first precursor is a group iii precursor and the second precursor is a group v precursor.
10. The method of claim 1, wherein the first precursor is selected from one or more of Zn, Mg, Ca, Sr, Al, Zr, Fe, Sc, Ti, Cr, Si, and Ni element precursors.
11. The method for preparing cadmium-free quantum dots according to any one of claims 1 to 10, wherein after the step S4, the method further comprises a step S5 of cladding a shell layer outside the quantum dot core.
12. A cadmium-free quantum dot, which is prepared by the preparation method of any one of claims 1 to 11.
13. An optoelectronic device comprising the cadmium-free quantum dot prepared by the preparation method of any one of claims 1 to 11.
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| CN114479862A (en) * | 2020-10-27 | 2022-05-13 | 武汉珈源同创科技有限公司 | Method for synthesizing CdSe quantum dots at gradient temperature change and CdSe quantum dots |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20160103366A (en) * | 2015-02-24 | 2016-09-01 | 엘지전자 주식회사 | InP-BASED QUANTUM DOT AND METHOD FOR PRODUCING THE SAME |
-
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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
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Non-Patent Citations (2)
| Title |
|---|
| GENOVEVA ZLATEVA ET AL.,: ""Precise size control and synchronized synthesis of six colors of CdSe quantum dots in a slow-increasing temperature gradient"", 《INORG. CHEM.》 * |
| PARTHIBAN RAMASAMY ET AL.,: ""Tunable, Bright, and Narrow-Band Luminescence from Colloidal Indium Phosphide Quantum Dots"", 《CHEM. MATER.》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114479862A (en) * | 2020-10-27 | 2022-05-13 | 武汉珈源同创科技有限公司 | Method for synthesizing CdSe quantum dots at gradient temperature change and CdSe quantum dots |
| CN114479862B (en) * | 2020-10-27 | 2023-06-20 | 武汉珈源同创科技有限公司 | Method for synthesizing CdSe quantum dots by gradient temperature change and CdSe quantum dots |
| CN112480906A (en) * | 2020-11-24 | 2021-03-12 | 苏州星烁纳米科技有限公司 | Indium-oxygen cluster compound and preparation method thereof, quantum dot prepared from indium-oxygen cluster compound and preparation method of quantum dot |
| WO2022111520A1 (en) * | 2020-11-24 | 2022-06-02 | 苏州星烁纳米科技有限公司 | Indium-oxygen cluster, preparation method therefor, quantum dot prepared therefrom and preparation method for quantum dot |
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