Quantum dot, preparation method thereof, electroluminescent diode and electronic device

Abstract

According to embodiments of the present invention, one aspect of the present invention can provide an InZnP:Se quantum dot that is environmentally friendly as it does not contain cadmium and has the characteristic of having a blue shift in the emission wavelength while maintaining other emission characteristics such as quantum efficiency and full width at half maximum compared to a quantum dot before doping, and can provide an electroluminescent diode and an electronic device including the same.

Description

Technology Field

[0001] The present invention relates to a quantum dot capable of having a blue-shifted emission wavelength after doping while maintaining other characteristics of the quantum dot's emission properties, such as quantum efficiency and full width at half maximum, before doping, a method for manufacturing the same, an electroluminescent diode, and an electronic device. Background Technology

[0002] Quantum dots are materials with a size of several nanometers that exhibit properties different from those of materials in their bulk state due to quantum confinement effects. The emission wavelengths that quantum dots can display vary depending on their intrinsic bandgap.

[0003] Quantum dots that can be utilized in next-generation high-brightness light-emitting diodes (LEDs), biosensors, lasers, and solar cell nanomaterials are required to exhibit various emission wavelengths. Recently, in line with the trend toward eco-friendliness, active development is underway for quantum dot materials based on III-V compounds to replace cadmium, which can exhibit various emission wavelengths and excellent emission properties.

[0004] The emission wavelength of quantum dots can be controlled in various ways based on the material's intrinsic bandgap.

[0005] Quantum dots generally exhibit a tendency for their emission wavelength to shift to blue as particle size decreases and to red as particle size increases; therefore, the emission wavelength of quantum dots can be controlled by adjusting particle size. However, it is difficult to control particle size during the manufacturing process for quantum dots based on III-V compounds, and it is particularly difficult to construct quantum dots with a blue-shifted emission wavelength by reducing particle size.

[0006] In addition to controlling particle size, there is a method of constructing core-shell quantum dots to control the emission wavelength of quantum dots. Quantum dots can be composed of a core material based on the above-mentioned III-V material and a shell heterostructure surrounding the core, and are classified into type 1, type 2, and reverse type 1 depending on the difference in band gap between the core and shell materials.

[0007] Quantum dots having the above type 1 structure are configured such that the band gap of the shell is larger than the band gap of the core, and in this configuration, most electrons and holes are trapped inside the core, allowing charge recombination to occur efficiently, and consequently, the quantum efficiency of the emitted light is relatively high, so this configuration is mainly suitable for light-emitting quantum dots.

[0008] The above type 2 structure is a quantum dot suitable for optoelectronic materials such as solar cells, as the band gaps of the core and shell are arranged in a stepped manner, and electrons and holes in the core move to the shell.

[0009] In the case of the above Reverse type I, unlike type 1, it has a configuration in which the bandgap of the core is larger than the bandgap of the shell.

[0010] When core-shell quantum dots are configured as type 1 suitable for the above-mentioned emitting quantum dots, the quantum confinement effect of the quantum dots increases, and also, due to the band gap between the core and the shell, leakage of some electrons may occur, so the emission wavelength is generally red-shifted.

[0011] Another method for converting the emission wavelength of quantum dots is doping with alloys and impurities. Alloys consist of a uniform mixture of constituent elements, and depending on the elements, a wide variety of emission characteristics can be exhibited.

[0012] Doped quantum dots are produced by adding other elements to a reference quantum dot, which allows for changes in wavelength while maintaining the emission characteristics of the reference quantum dot. However, doped quantum dots generally exhibit a red shift in emission wavelength, and changes in full-width and quantum efficiency result in degraded emission characteristics compared to undoped quantum dots.

[0013] Therefore, a technology is required that allows the emission wavelength to be blue-shifted while maintaining other emission characteristics, such as full width at half maximum and quantum efficiency, by adding appropriate doping elements to quantum dots based on III-V materials. The problem to be solved

[0014] One aspect of the present invention aims to provide an InZnP quantum dot that does not contain cadmium and a quantum dot that is doped with Se.

[0015] Another aspect of the present invention aims to provide an InZnP:Se quantum dot having a blue shift in emission wavelength while maintaining other emission characteristics, such as quantum efficiency and full width at half maximum, compared to the quantum dot before doping, by doping the InZnP quantum dot with Se.

[0016] In addition, as another aspect of the present invention, the purpose is to provide a blue-shifted electroluminescent diode and an electronic device while maintaining luminescence characteristics. means of solving the problem

[0017] The quantum dots comprising InZnP:Se according to the present invention preferably comprise a first semiconductor nanocrystal InZnP quantum dot core comprising In, Zn, and P, and the InZnP quantum dot core doped with element Se.

[0018] It is desirable that the emission wavelength of the above quantum dots is blue-shifted after doping compared to before doping.

[0019] It is preferable that the doping ratio of Se to In is 0.01 to 10 mol%.

[0020] It is preferable that the ratio of Zn to In is 0.01 to 10 mol%.

[0021] It is preferable to further include a second semiconductor nanocrystal shell containing group II and group VI elements on the above InZnP:Se quantum dots.

[0022] It is preferable that the group II elements of the second semiconductor nanocrystal shell include one or more of Be, Mg, Ca, Sr, Ba, Zn, and Hg.

[0023] It is preferable that the group VI elements of the second semiconductor nanocrystal shell include one or more of S, Se, and Te.

[0024] It is preferable to manufacture the above InZnP quantum dot core using a zinc oxo (Zn-oxo) cluster of the following [Chemical Formula 1].

[0025] [Chemical Formula 1] Zn x O y (Carboxylate) Z

[0026] In the above chemical formula 1, x, y, and z are natural numbers, x > y, and satisfy the relationship x+y=z or 2x=2y+z.

[0027] The above InZnP quantum dot core is preferably manufactured by placing an indium precursor and a zinc oxo (Zn-oxo) cluster into a reactor and injecting a phosphorus precursor into the reactor.

[0028] The above InZnP:Se quantum dots are preferably doped with Se by injecting Se-TOP into the InZnP quantum dots and then reacting them.

[0029] As another embodiment of the present invention, the method for manufacturing quantum dots according to the present invention preferably comprises the steps of: placing an indium precursor and a zinc oxo (Zn-oxo) cluster of [Chemical Formula 1] below into a reactor and heating it; and synthesizing an InZnP core by injecting a phosphorus precursor into the reactor using a hot-injection method.

[0030] [Chemical Formula 1] Zn x O y (Carboxylate) Z

[0031] In the above chemical formula 1, x, y, and z are natural numbers, x > y, and satisfy the relationship x+y=z or 2x=2y+z.

[0032] The method for manufacturing quantum dots according to the present invention preferably further comprises the steps of: injecting 0.01 mmol to 0.1 mmol of a Se-TOP solution into the synthesized InZnP core; and reacting for 0 to 60 minutes after injecting the Se-TOP solution to control the degree of blue shift of the InZnP:Se quantum dot emission wavelength.

[0033] In another aspect, according to embodiments of the present invention, an electroluminescent diode comprising the quantum dots is provided.

[0034] In another aspect, according to embodiments of the present invention, an electronic device is provided comprising a display device including the electroluminescent diode and a control unit for driving the display device. Effects of the invention

[0035] According to embodiments of the present invention, one aspect of the present invention can provide an InZnP:Se quantum dot that is environmentally friendly as it does not contain cadmium and has the characteristic of having a blue shift in the emission wavelength while maintaining other emission characteristics such as quantum efficiency and full width at half maximum compared to a quantum dot before doping, and can provide an electroluminescent diode and an electronic device including the same. Specific details for implementing the invention

[0036] In the following description of the invention, only the parts necessary for understanding the embodiments are described, and the method for manufacturing quantum dots is described in detail. Unless otherwise defined, technical or scientific terms used in the description represent the meaning commonly understood by those skilled in the art to which the invention pertains. In describing the invention, if it is determined that a detailed description may obscure the essence of the invention, such detailed description is omitted.

[0037] In describing the components of the present invention, when terms such as "includes," "has," or "consists of" are used, other parts may be added unless "only" is used. When a component is expressed in the singular, it may include a plural form unless otherwise specified.

[0038] Additionally, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the present invention. These terms are used merely to distinguish the components from other components, and the essence, order, sequence, or number of the components are not limited by such terms.

[0039] In describing the positional relationship of components, where it is stated that two or more components are "connected," "combined," or "joined," it should be understood that while the two or more components may be directly "connected," "combined," or "joined," they may also be "connected," "combined," or "joined" with other components "intervened." Here, the other components may be included in one or more of the two or more components that are "connected," "combined," or "joined" with one another.

[0040] Furthermore, when it is stated that one component is "above" or "on" another component, this should be understood to include not only the case where it is "directly above" the other component, but also the case where there is another component in between. Conversely, when it is stated that one component is "directly above" another part, it should be understood to mean that there is no part in between. Additionally, being "above" or "on" a reference part means being located above or below the reference part, and does not necessarily mean being located "above" or "on" in the opposite direction of gravity.

[0041] In describing the temporal flow relationship regarding components, methods of operation, or methods of production, for example, when the temporal or sequential relationship is described using "after," "following," "next," or "before," it may include cases where the relationship is not continuous unless "immediately" or "directly" is used.

[0042] Meanwhile, where numerical values ​​or corresponding information regarding a component are mentioned, even without separate explicit notation, the numerical values ​​or corresponding information may be interpreted as including a margin of error that may occur due to various factors (e.g., process factors, internal or external shock, noise, etc.).

[0043] Furthermore, in describing the present invention, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0044] In addition, in describing the present invention, "planar" means when the object part is viewed from above, and "cross-sectional" means when the cross-section obtained by vertically cutting the object part is viewed from the side.

[0045] In addition, in describing the present invention, "Group" refers to a group of the periodic table of elements.

[0046] Here, "Group II" may include Group IIA and Group IIB, and Group II elements include, but are not limited to, Be, Mg, Ca, Sr, Zn, Cd and Hg.

[0047] "Group III" may include Group IIIA and Group IIIB, and Group III elements include, but are not limited to, In, Ga and Al.

[0048] "Group V" may include Group V, and Group V elements include, but are not limited to, P, As, Sb, Bi, and N.

[0049] "Group VI" may include Group VIA, and Group VI elements include, but are not limited to, S, Se, and Te.

[0050] In the present application, the organic electric device may mean a component(s) between an anode and a cathode, or an organic light-emitting diode comprising an anode, a cathode, and a component(s) located between them.

[0051] Additionally, depending on the case, the organic electrical device in this application may refer to an organic light-emitting diode and a panel including the same, or an electronic device including a panel and a circuit. Here, for example, the electronic device may include, but is not limited to, display devices, lighting devices, solar cells, portable or mobile terminals (e.g., smartphones, tablets, PDAs, electronic dictionaries, PMPs, etc.), navigation terminals, game consoles, various TVs, various computer monitors, etc., and may be any type of device that includes the above-mentioned component(s).

[0052] As used herein, the term "precursor" refers to a chemical substance prepared in advance for reacting quantum dots, encompassing all compounds including metals, ions, elements, compounds, complexes, clusters, etc. It is not necessarily limited to the final substance of a reaction but refers to any substance obtainable at any arbitrarily determined stage.

[0053] The first semiconductor nanocrystal quantum dot core according to the present invention comprises an InZnP core formed by reacting an indium precursor, a zinc precursor, and a phosphorus precursor, and a Se precursor introduced into the synthesized InZnP core to form a Se-doped InZnP core (InZnP:Se).

[0054] The above indium precursor may be one or more selected from the group consisting of, for example, indium(III)acetylacetonate, indium(III)chloride, indium(III)acetate, trimethyl indium, alkyl indium, aryl indium, indium (III)myristate, and indium (III)myristate acetate.

[0055] The above zinc precursor is, for example, dimethyl zinc, diethyl zinc, zinc acetate, zinc acetate dihydrate, zinc acetylacetonate, zinc acetylacetonate hydrate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc fluoride tetrahydrate, zinc carbonate, zinc cyanide, zinc nitrate, zinc nitrate hexahydrate, zinc oxide, zinc peroxide, zinc perchlorate, zinc perchlorate It may be one or more from the group consisting of zinc perchlorate hexahydrate, zinc sulfate, diphenyl zinc, zinc naphthenate, and zinc stearate.

[0056] In addition, the zinc precursor may be a zinc pre-precursor constituting another zinc precursor.

[0057] The above zinc precursor may be zinc carboxylate. The above zinc carboxylate is Zn(Carboxylate) nIt can be denoted as such. For example, the zinc carboxylate may be Zn(Oleate)2, but the type of zinc precursor is not limited to Zn(Oleate)2.

[0058] The above carboxylate can be prepared by mixing the above zinc pre-precursor with a carboxylic acid. The carboxylic acid for preparing zinc carboxylate may be, for example, one or more selected from the group consisting of palmitic acid, myristateic acid, oleic acid, and stearic acid. For example, if the zinc precursor is Zn(Oleate)2, Zn(Oleate)2 can be prepared by reacting the zinc pre-precursor, zinc acetate, with oleic acid.

[0059] The above zinc precursor may be, for example, a zinc oxo cluster. For example, the zinc oxo cluster may be a zinc oxo (Zn-oxo) cluster.

[0060] A zinc oxo cluster can be represented by the following chemical formula 1.

[0061] [Chemical Formula 1] Zn x O y (Carboxylate) z

[0062] In the above chemical formula 1, x, y, and z are natural numbers; x > y, and satisfy the relationship x+y=z or 2x=2y+z.

[0063] The above zinc oxo clusters are, for example, Zn7O2(carboxylate)9, Zn4O(carboxylate)6, and Zn7O2(carboxylate) 10 It may be one or more selected from a group consisting of

[0064] The above zinc oxo cluster can be prepared by heating a solution containing the carboxylate of the zinc precursor described above. For example, Zn(Oleate)2 is thermally decomposed to obtain Zn7O2(carboxylate)9, Zn4O(carboxylate)6, and Zn7O2(carboxylate). 10 It can form zinc oxo clusters (Zn-oxo).

[0065] The above phosphorus precursor may be one or more organometallic phosphorus selected from the group consisting of, for example, tris(trimethylsilyl)phosphine (TMSP), aminophosphine, white phosphorus, tri(pyrazolyl)phosphane, trioctylphosphine, and calcium phosphide.

[0066] For example, the phosphorus precursor may be one or more selected from the group consisting of tris(trimethylsilyl)phosphine (TMSP) and trioctylphosphine.

[0067] In the present invention, the Se precursor used when doping Se into the synthesized InZnP quantum dots may be, for example, one or more selected from the group consisting of SeCl2, Se, Se-TOP, Se-DPP, and Se-ODE.

[0068] In the present invention, the quantum dot core may include a core material and a doping element. The core including the core and the doping element may be expressed as 'core:doping element'. For example, it may be expressed as an InZnP:Se core.

[0069] In one embodiment, the Se doped into the InZnP core may be formed inside or on the surface of the InZnP core.

[0070] In one embodiment, the ratio of Zn to In in the core portion of the InZnP:Se core is 1 to 10 mol%.

[0071] In one embodiment, the doping ratio of Se to In in the core portion of the InZnP:Se core is 0.01 to 10 mol%, preferably 0.02 to 7 mol%, and more preferably 0.03 to 5 mol%.

[0072] The InZnP:Se quantum dots according to the present invention can have a blue shift with a shorter wavelength of emission than before doping while maintaining other emission characteristics such as full width at half maximum and quantum efficiency.

[0073] The quantum dot according to the present invention may include a shell composed of an InZnP:Se core and a second semiconductor nanocrystal disposed on the InZnP:Se core.

[0074] In one embodiment, the second semiconductor nanocrystal shell may be composed of a group II element and a group VI element. As the group II element, one may be used from the group consisting of Be, Mg, Ca, Sr, Ba, Zn, and Hg or a combination thereof, and as the group VI element, one may be selected from the group consisting of S, Se, and Te or a combination thereof.

[0075] In one embodiment, the quantum dot may be a core-multilayer shell structure having an InZnP:Se core, a first shell disposed on (or immediately above) the core, and a second shell disposed on (immediately above) the first shell.

[0076] In quantum dot manufacturing methods, alloy quantum dots can be formed by simultaneously applying the precursors constituting the quantum dots in the same reaction step. For example, InZnPSe alloy quantum dots can be formed by simultaneously using indium precursors, zinc precursors, phosphorus precursors, and selenium precursors in the same reaction step.

[0077] The doped quantum dots according to the present invention may include the steps of constituting quantum dots and reacting by introducing a doping element precursor into the synthesized quantum dots. For example, InZnP:Se quantum dots may be constituted by first constituting InZnP quantum dots with an indium precursor, a zinc precursor, and a phosphorus precursor, and then applying a Se precursor.

[0078] In one embodiment, the InZnP quantum dots synthesized with a zinc oxo (Zn-oxo) precursor have a relatively high Zn content, which is advantageous for Se doping. During the process of synthesizing InZnP quantum dots, the zinc precursor plays a role in controlling reactivity and ensuring excellent crystallinity in the synthesis of InZnP. Using zinc oxo (Zn-oxo) as the zinc precursor improves reactivity, which is advantageous for increasing the Zn content within the InZnP quantum dots.

[0079] A method for manufacturing quantum dots according to the present invention includes a step of synthesizing an InZnP core and a step of doping Se into the InZnP core.

[0080] In one embodiment, the InZnP:Se quantum dots can be produced using a hot-injection method and an in-situ method, wherein an InZnP core is formed using an In precursor, a P precursor, a Zn precursor, preferably a zinc oxo (Zn-oxo) precursor inside a heated reactor, and a Se precursor is injected into the synthesized InZnP core.

[0081] In one embodiment, the degree of blue shift of the quantum dot emission wavelength can be controlled by adjusting the amount of Se precursor added and the reaction time after adding the Se precursor.

[0082] The method for manufacturing quantum dots according to the present invention may include the step of forming a second semiconductor nanocrystal shell composed of a group II-VI compound on the InZnP:Se quantum dot core.

[0083] In another aspect, according to embodiments of the present invention, an electronic device comprising an electroluminescent diode including the quantum dot, a display device including the electroluminescent diode, and a control unit for driving the display device may be provided.

[0084] In describing the electronic device according to the embodiments of the present invention, details regarding the electroluminescent diode are omitted, as they are identical to those described above regarding the electroluminescent diode according to the embodiments of the present invention unless otherwise specifically explained.

[0086] Specific embodiments are presented below. However, the embodiments described below are merely for the purpose of specifically illustrating or explaining the invention and should not limit the scope of the invention.

[0087] [Example]

[0088] (1) Zn(oleate) 2 Preparation of a zinc precursor solution containing

[0089] 5.5 g (30 mmol) of zinc acetate (Zn acetate) and 19 mL (60 mmol) of oleic acid were placed in a 250 mL flask, and the mixture was heated to room temperature (RT) for 1 hour under reduced pressure, then heated to 180°C over 10 minutes under reduced pressure, and reacted for 2 hours. After creating an argon atmosphere in the mixture, 41 mL of octadecene was injected, and the temperature was reduced to room temperature. The concentration of the mixture was 0.5 M, and 0.5 mmol of Zn(oleate)2 was obtained when 1 mL was taken.

[0091] (2) Preparation of a zinc precursor solution containing zinc oxo (Zn-oxo) clusters

[0092] 5.5 g (30 mmol) of zinc acetate and 19 mL (60 mmol) of oleic acid were placed in a 250 mL three-necked flask and heated under reduced pressure at room temperature (RT) for 1 hour to produce a 0.5 mmol Zn(oleate)2 solution. The Zn(oleate)2 solution was heated to 180°C over 20 minutes under reduced pressure and reacted for 1 hour. The solution was then heated to 300°C over 10 minutes under reduced pressure and reacted for 20 minutes. After creating a nitrogen atmosphere for the mixed solution, 41 mL of octadecene was injected and the temperature was reduced to room temperature. The concentration of the mixed solution is 0.5 M.

[0094] (3) Example 1 (InZnP:Se quantum dot synthesis)

[0095] 1) In a 250 mL three-necked round-bottom flask equipped with a reflux device, add 0.45 mmol of indium chloride, 12.5 mmol of Zn-oxo, 16 mL of 1-octadecene, and 8 mL of oleic acid. Heat to 110°C and maintain at approximately 0.005 torr using a vacuum pump for 1 hour. Then, replace the atmosphere with nitrogen, heat to 260°C, and add 0.6 mL of Tris(trimethylsilyl)phosphine and trioctylphosphine.

[0096] 2) After adding the above phosphorus precursor, add 0.01 ml of 1 M Se-TOP solution. Then, stir at 260°C for 60 minutes.

[0098] (4) Example 2 (InZnP:Se quantum dot synthesis)

[0099] Quantum dots are obtained in the same manner as in Example 1, except that in step 2) of Example 1, the phosphorus precursor is added and stirred for 3 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 57 minutes.

[0101] (5) Example 3 (InZnP:Se quantum dot synthesis)

[0102] Quantum dots are obtained in the same manner as in Example 1, except that in step 2) of Example 1, the phosphorus precursor is added and stirred for 6 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 54 minutes.

[0104] (6) Example 4 (InZnP:Se quantum dot synthesis)

[0105] Quantum dots are obtained in the same manner as in Example 1, except that in step 2) of Example 1, the phosphorus precursor is added and stirred for 10 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 50 minutes.

[0107] (7) Example 5 (InZnP:Se / ZnS quantum dot synthesis)

[0108] 1) Add 0.45 mmol of indium chloride, 12.5 mmol of Zn-oxo, 16 mL of 1-octadecene, and 8 mL of oleic acid to a 250 mL three-necked round-bottom flask equipped with a reflux device, heat to 110°C, and maintain a vacuum of approximately 0.005 torr for 1 hour using a vacuum pump. Then, replace the atmosphere with nitrogen, heat to 260°C, and add 0.6 mL of Tris(trimethylsilyl)phosphine and trioctylphosphine.

[0109] 2) After adding the above phosphorus precursor, add 0.01 ml of 1 M Se-TOP solution. Then, stir at 260°C for 60 minutes.

[0110] 3) Next, to form a shell, 1.35 mmol of sulfur is dissolved in Trioctyl Phosphine at a concentration of 1 M and injected into a reactor, then heated to 300°C and stirred for 9 hours.

[0112] (8) Example 6 (InZnP:Se / ZnS quantum dot synthesis)

[0113] In step 2) of Example 5, quantum dots are obtained in the same manner as in Example 5, except that the phosphorus precursor is added and stirred for 3 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 57 minutes.

[0115] (9) Example 7 (InZnP:Se / ZnS quantum dot synthesis)

[0116] Quantum dots are obtained in the same manner as in Example 5, except that in step 2) of Example 5, the phosphorus precursor is added and stirred for 6 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 54 minutes.

[0118] (10) Example 8 (InZnP:Se / ZnS quantum dot synthesis)

[0119] In step 2) of Example 5, quantum dots are obtained in the same manner as in Example 5, except that the phosphorus precursor is added and stirred for 10 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 50 minutes.

[0121] (11) Example 9 (InZnP:Se / ZnSe quantum dot synthesis)

[0122] 1) Add 0.45 mmol of indium chloride, 12.5 mmol of Zn-oxo, 16 mL of 1-octadecene, and 8 mL of oleic acid to a 250 mL three-necked round-bottom flask equipped with a reflux device, heat to 110°C, and maintain a vacuum of approximately 0.005 torr for 1 hour using a vacuum pump. Then, replace the atmosphere with nitrogen, heat to 260°C, and add 0.6 mL of Tris(trimethylsilyl)phosphine and trioctylphosphine.

[0123] 2) After adding the above phosphorus precursor, add 0.01 ml of 1 M Se-TOP solution. Then, stir at 260°C for 60 minutes.

[0124] 3) Next, to form a shell, 2.75 mmol of selenium is dissolved in Trioctyl Phosphine at a concentration of 1 M and injected into a reactor, then heated to 300°C and stirred for 9 hours.

[0126] (12) Example 10 (InZnP:Se / ZnSe quantum dot synthesis)

[0127] In step 2) of Example 9, quantum dots are obtained in the same manner as in Example 9, except that the phosphorus precursor is added and stirred for 3 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 57 minutes.

[0129] (13) Example 11 (InZnP:Se / ZnSe quantum dot synthesis)

[0130] Quantum dots are obtained in the same manner as in Example 9, except that in step 2) of Example 9, the phosphorus precursor is added and stirred for 6 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 54 minutes.

[0132] (14) Example 12 (InZnP:Se / ZnSe quantum dot synthesis)

[0133] Quantum dots are obtained in the same manner as in Example 9, except that in step 2) of Example 9, the phosphorus precursor is added and stirred for 10 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 50 minutes.

[0135] (15) Example 13 (InZnP:Se / ZnSe / ZnS quantum dot synthesis)

[0136] 1) Add 0.45 mmol of indium chloride, 12.5 mmol of Zn-oxo, 16 mL of 1-octadecene, and 8 mL of oleic acid to a 250 mL three-necked round-bottom flask equipped with a reflux device, heat to 110°C, and maintain a vacuum of approximately 0.005 torr for 1 hour using a vacuum pump. Then, replace the atmosphere with nitrogen, heat to 260°C, and add 0.6 mL of Tris(trimethylsilyl)phosphine and trioctylphosphine.

[0137] 2) After adding the above phosphorus precursor, add 0.01 ml of 1 M Se-TOP solution. Then, stir at 260°C for 54 minutes.

[0138] 3) Next, to form a shell, 2.75 mmol of selenium is dissolved in Trioctyl Phosphine at a concentration of 1 M and injected into a reactor, then heated to 300°C and stirred for 9 hours.

[0139] 4) Dissolve 1.35 mmol of sulfur in trioctyl phosphine to a concentration of 1 M and inject it into a reactor, then heat to 300°C and stir for 1 hour. Cool to room temperature to terminate the reaction.

[0141] (16) Example 14 (InZnP:Se / ZnSe / ZnS quantum dot synthesis)

[0142] In step 2) of Example 13, quantum dots are obtained in the same manner as in Example 13, except that the phosphorus precursor is added and stirred for 3 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 57 minutes.

[0144] (17) Example 15 (InZnP:Se / ZnSe / ZnS quantum dot synthesis)

[0145] In step 2) of Example 13, quantum dots are obtained in the same manner as in Example 13, except that the phosphorus precursor is added and stirred for 6 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 54 minutes.

[0147] (18) Example 16 (Synthesis of InZnP:Se / ZnSe / ZnS quantum dots)

[0148] In step 2) of Example 13, quantum dots are obtained in the same manner as in Example 13, except that the phosphorus precursor is added and stirred for 10 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 50 minutes.

[0150] (19) Example 17 (InZnP:Se / ZnSeS / ZnS quantum dot synthesis)

[0151] 1) Add 0.45 mmol of indium chloride, 12.5 mmol of Zn-oxo, 16 mL of 1-octadecene, and 8 mL of oleic acid to a 250 mL three-necked round-bottom flask equipped with a reflux device, heat to 110°C, and maintain the pressure at approximately 0.005 torr using a vacuum pump for 1 hour. Then, replace the atmosphere with nitrogen, heat to 260°C, and add 0.6 mL of Tris(trimethylsilyl)phosphine and trioctylphosphine.

[0152] 2) After adding the above phosphorus precursor, add 0.01 ml of 1 M Se-TOP solution. Then, stir at 260°C for 60 minutes.

[0153] 3) Next, to form a shell, 2.75 mmol of selenium and 1.35 mmol of sulfur are each dissolved in Trioctyl phosphine at a concentration of 1 M and injected into a reactor, then heated to 300°C and stirred for 9 hours.

[0154] 4) Dissolve 1.35 mmol of sulfur in trioctyl phosphine to a concentration of 1 M and inject it into the reactor. Then, heat to 300°C and stir for 1 hour. Cool to room temperature to terminate the reaction.

[0156] (20) Example 18 (InZnP:Se / ZnSeS / ZnS quantum dot synthesis)

[0157] In step 2) of Example 17, quantum dots are obtained in the same manner as in Example 17, except that the phosphorus precursor is added and stirred for 3 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 57 minutes.

[0159] (21) Example 19 (Synthesis of InZnP:Se / ZnSeS / ZnS quantum dots)

[0160] In step 2) of Example 17, quantum dots are obtained in the same manner as in Example 17, except that the phosphorus precursor is added and stirred for 6 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 54 minutes.

[0162] (22) Example 20 (InZnP:Se / ZnSeS / ZnS quantum dot synthesis)

[0163] In step 2) of Example 17, quantum dots are obtained in the same manner as in Example 17, except that the phosphorus precursor is added and stirred for 10 minutes, and 0.01 ml of 1 M Se-TOP solution is added and stirred for 50 minutes.

[0165] (23) Example 21 (InZnP:Se / ZnSeS / ZnS quantum dot synthesis)

[0166] In step 2) of Example 17, quantum dots are obtained in the same manner as in Example 17, except that after adding the phosphorus precursor, 0.05 ml of 1 M Se-TOP solution is added and stirred for 60 minutes.

[0168] (24) Example 22 (InZnP:Se / ZnSeS / ZnS quantum dot synthesis)

[0169] In step 2) of Example 17, quantum dots are obtained in the same manner as in Example 17, except that the phosphorus precursor is added and stirred for 3 minutes, and 0.05 ml of 1 M Se-TOP solution is added and stirred for 57 minutes.

[0171] (25) Example 23 (InZnP:Se / ZnSeS / ZnS quantum dot synthesis)

[0172] Quantum dots are obtained in the same manner as in Example 17, except that in step 2) of Example 17, the phosphorus precursor is added and stirred for 6 minutes, and 0.05 ml of 1 M Se-TOP solution is added and stirred for 54 minutes.

[0174] (26) Example 24 (InZnP:Se / ZnSeS / ZnS quantum dot synthesis)

[0175] In step 2) of Example 17, quantum dots are obtained in the same manner as in Example 17, except that the phosphorus precursor is added and stirred for 10 minutes, and 0.05 ml of 1 M Se-TOP solution is added and stirred for 50 minutes.

[0177] (27) Example 25 (InZnP:Se / ZnSeS / ZnS quantum dot synthesis)

[0178] In step 2) of Example 17, quantum dots are obtained in the same manner as in Example 17, except that the phosphorus precursor is added without stirring, and 0.1 ml of 1 M Se-TOP solution is added and stirred for 60 minutes.

[0180] (28) Example 26 (InZnP:Se / ZnSeS / ZnS quantum dot synthesis)

[0181] In step 2) of Example 17, quantum dots are obtained in the same manner as in Example 17, except that the phosphorus precursor is added and stirred for 3 minutes, and 0.1 ml of 1 M Se-TOP solution is added and stirred for 57 minutes.

[0183] (29) Example 27 (Synthesis of InZnP:Se / ZnSeS / ZnS quantum dots)

[0184] In step 2) of Example 17, quantum dots are obtained in the same manner as in Example 17, except that the phosphorus precursor is added and stirred for 6 minutes, and 0.1 ml of 1 M Se-TOP solution is added and stirred for 54 minutes.

[0186] (30) Comparative Example 1 (InZnP quantum dot synthesis)

[0187] Quantum dots are obtained in the same way, except for process 2) of Example 1.

[0189] (31) Comparative Example 2 (InZnP:Mn quantum dot synthesis)

[0190] Quantum dots are obtained in the same manner as in Example 1, except that 0.35 ml of Tris(trimethylsilyl)phosphine is used instead of 0.6 ml of Tris(trimethylsilyl)phosphine and trioctylphosphine in step 1) of Example 1, and 0.1 mmol of Mn(Acetylacetone)-TOP solution is used instead of Se-TOP solution in step 2).

[0192] (32) Comparative Example 3 (InZnP:Cu quantum dot synthesis)

[0193] Quantum dots are obtained in the same manner as in Example 1, except that 0.35 ml of Tris(trimethylsilyl)phosphine is used instead of 0.6 ml of Tris(trimethylsilyl)phosphine and trioctylphosphine in step 1) of Example 1, and 0.1 mmol of Cu(acetate)-TOP solution is used instead of Se-TOP solution in step 2).

[0195] (33) Comparative Example 4 (InZnP / ZnS quantum dot synthesis)

[0196] Quantum dots are obtained in the same way, except for process 2) of Example 5.

[0198] (34) Comparative Example 5 (InZnP / ZnSe quantum dot synthesis)

[0199] Quantum dots are obtained in the same way, except for process 2) of Example 9.

[0201] (35) Comparative Example 6 (InZnP / ZnSe / ZnS quantum dot synthesis)

[0202] Quantum dots are obtained in the same way, except for process 2) of Example 13.

[0204] (36) Comparative Example 7 (Synthesis of InZnP / ZnSeS / ZnS quantum dots)

[0205] Quantum dots are obtained in the same way, except for process 2) of Example 17.

[0207] Table 1 shows the results measured by Otsuka Electronics’ QE-2000 instrument and confirms the optical properties [Emission Peak, Quantum Yield, Full Width at Half Maximum, FWHM] of the synthesized quantum dots.

[0208] Composition of quantum dots Emission peak (nm) FWHM (nm) QY (%) Se input amount (mmol) Reaction time after Se injection (min) Comparative Example 1 InZnP 501 65 31 - - Comparative Example 2 InZnP:Mn 537 89 27 - - Comparative Example 3 InZnP:Cu 548 93 23 - - Comparative Example 4 InZnP / ZnS 521 48 50 - - Comparative Example 5 InZnP / ZnSe 523 43 52 - - Comparative Example 6 InZnP / ZnSe / ZnS 533 40 85 - - Comparative Example 7 InZnP / ZnSeS / ZnS 530 39 89 - - Example 1 InZnP:Se 486 65 31 0.01 60 Example 2 InZnP:Se 490 66 29 0.01 57 Example 3 InZnP:Se 493 65 30 0.01 54 Example 4 InZnP:Se 496 66 29 0.01 50 Example 5 InZnP:Se / ZnS 505 47 50 0.01 60 Example 6 InZnP:Se / ZnS 508 47 49 0.01 57 Example 7 InZnP:Se / ZnS 511 47 48 0.01 54 Example 8 InZnP:Se / ZnS 515 48 50 0.01 50 Example 9 InZnP:Se / ZnSe 508 43 52 0.01 60 Example 10 InZnP:Se / ZnSe 512 42 50 0.01 57 Example 11 InZnP:Se / ZnSe 515 43 51 0.01 54 Example 12 InZnP:Se / ZnSe 519 43 51 0.01 50 Example 13 InZnP:Se / ZnSe / ZnS 517 39 86 0.01 60 Example 14 InZnP:Se / ZnSe / ZnS 520 39 87 0.01 57 Example 15 InZnP:Se / ZnSe / ZnS 523 39 87 0.01 54 Example 16 InZnP:Se / ZnSe / ZnS 526 39 87 0.01 50 Example 17 InZnP:Se / ZnSeS / ZnS 514 38 90 0.01 60 Example 18 InZnP:Se / ZnSeS / ZnS 518 39 90 0.01 57 Example 19 InZnP:Se / ZnSeS / ZnS 522 37 92 0.01 54 Example 20 InZnP:Se / ZnSeS / ZnS 525 37 91 0.01 50 Example 21 InZnP:Se / ZnSeS / ZnS 510 39 89 0.05 60 Example 22 InZnP:Se / ZnSeS / ZnS 514 39 89 0.05 57 Example 23 InZnP:Se / ZnSeS / ZnS 518 38 90 0.05 54 Example 24 InZnP:Se / ZnSeS / ZnS 521 37 90 0.05 50 Example 25 InZnP:Se / ZnSeS / ZnS 505 39 89 0.1 60 Example 26 InZnP:Se / ZnSeS / ZnS 509 38 89 0.1 57 Example 27 InZnP:Se / ZnSeS / ZnS 513 37 89 0.1 54

[0210] Looking at Table 1 above, when comparing InZnP quantum dots without a shell, or composed of a single shell or a double shell, with Se-doped InZnP quantum dots (Example 1 and Comparative Example 1; Example 5 and Comparative Example 4; Example 9 and Comparative Example 5; Example 13 and Comparative Example 6; and Example 17 and Comparative Example 7), it was shown that regardless of the shell composition, other luminescence characteristics such as the full width at half maximum and quantum efficiency of the quantum dots are maintained while the emission wavelength is blue-shifted.

[0211] In addition, when comparing the results of Comparative Examples 2 and 3, which were doped with Mn and Cu in addition to Se, with the results of the Examples, the emission wavelength showed a tendency to be red-shifted.

[0212] It is believed that the doped Se can specifically act as an impurity in the InZnP quantum dots to form metastable levels with a larger band gap than InZnP, and that as Se binds to InZnP through doping, it forms new molecular orbitals, and at this time, electrons are attracted to Se, which has higher electronegativity, thereby expanding the orbital energy difference centered on InZnP more significantly, making blue shift possible.

[0213] In addition, referring to the results of Examples 1 to 20, it was observed that the degree of blue shift of the emission wavelength tended to decrease as the reaction time after adding Se-TOP shortened.

[0214] In addition, from the results of Examples 17, 21, and 25, it was shown that under the same conditions, the degree of blue shift tended to increase as the amount of Se-TOP added increased.

[0215] This indicates that the degree of blue shift of InZnP quantum dots can be controlled by adjusting the amount of selenium precursor added and the reaction time after addition.

[0216] The foregoing description is merely illustrative of the present invention, and those skilled in the art to which the present invention pertains will be able to make various modifications within the scope of the essential characteristics of the present invention. Accordingly, the embodiments disclosed herein are intended to illustrate, not limit, the present invention, and the spirit and scope of the present invention are not limited by such embodiments. The scope of protection of the present invention shall be interpreted by the claims below, and all technology within an equivalent scope shall be interpreted as being included within the scope of rights of the present invention.

Claims

Claim 1 A first semiconductor nanocrystal InZnP quantum dot core comprising In, Zn and P, and a quantum dot comprising InZnP:Se in which the InZnP quantum dot core is doped with the element Se. Claim 2 In claim 1, the quantum dot is characterized by the fact that the emission wavelength is blue-shifted after doping compared to before doping. Claim 3 A quantum dot according to claim 1, characterized in that the doping ratio of Se to In is 0.01 to 10 mol%. Claim 4 A quantum dot according to claim 1, characterized in that the ratio of Zn to In is 0.01 to 10 mol%. Claim 5 In claim 1, a quantum dot comprising a second semiconductor nanocrystal shell containing a group II element and a group VI element on the InZnP:Se quantum dot. Claim 6 In claim 5, the group II element of the second semiconductor nanocrystal shell comprises one or more of Be, Mg, Ca, Sr, Ba, Zn, and Hg. Claim 7 In claim 5, the group VI element of the second semiconductor nanocrystal shell is a quantum dot comprising one or more of S, Se, and Te. Claim 8 Quantum dot according to claim 1, wherein the InZnP quantum dot core is prepared from a zinc oxo (Zn-oxo) cluster of the following [Chemical Formula 1]: [Chemical Formula 1] Zn x O y (Carboxylate) Z In the above chemical formula 1, x, y, and z are natural numbers, x > y, and satisfy the relationship x+y=z or 2x=2y+z. Claim 9 In claim 1, the quantum dot is characterized in that the InZnP quantum dot core is manufactured by placing an indium precursor and a zinc oxo (Zn-oxo) cluster into a reactor and injecting a phosphorus precursor into the reactor. Claim 10 In claim 1, the InZnP:Se quantum dot is characterized by being doped with Se by injecting Se-TOP into the InZnP quantum dot and then reacting it. Claim 11 delete Claim 12 delete Claim 13 An electroluminescent diode comprising quantum dots according to claim 1. Claim 14 An electronic device comprising: a display device including an electroluminescent diode according to claim 13; and a control unit for driving the display device.

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