Quantum dot, method for preparing quantum dot and electronic equipment

Abstract

The invention relates to a quantum dot, a method for preparing the quantum dot and electronic equipment. According to one aspect, there is provided a quantum dot comprising copper (Cu), a Group III element, and a Group VI element, where the quantum dot further comprises a halogen component selected from the group consisting of iodide ions, bromide ions, chloride ions, fluoride ions, and combinations thereof, where the molar ratio of the halogen component to the copper (Cu) and the Group III element is in the range of about 0.01 to about 0.5, and where the molar ratio of the halogen component to the copper (Cu) and the Group III element is in the range of about 0.01 to about 0.5. And the full width at half maximum (FWHM) of the photoluminescence spectrum of the quantum dot is 80 nm or less.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application is based on and claims the benefit of priority from Korean Patent Application No. 10-2023-0126407 filed on September 21, 2023, in the Korean Intellectual Property Office, and Korean Patent Application No. 10-2024-0112330 filed on August 21, 2024, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein in their entirety by reference. Technical Field

[0003] One or more embodiments relate to a quantum dot, a method of preparing a quantum dot, and an electronic device including the quantum dot. Background Art

[0004] Quantum dots are nanocrystals of semiconductor materials and are materials that exhibit quantum confinement effects. When quantum dots receive light from an excitation source and reach an energy excitation state, they spontaneously emit energy according to the corresponding energy band gap. In this regard, even for the same material, quantum dots exhibit the characteristic of having a wavelength that varies with particle size. Therefore, the size of quantum dots can be adjusted to obtain light within the desired wavelength range, and characteristics such as excellent color purity and high luminous efficiency can be exhibited. Therefore, quantum dots are suitable for various devices or equipment. Summary of the invention

[0005] One or more embodiments include quantum dots having narrow full width at half maximum (FWHM) and controlled emission wavelength, methods of preparing quantum dots, and electronic devices including quantum dots.

[0006] Additional aspects will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of embodiments of the disclosure.

[0007] According to one or more embodiments, the quantum dots include copper (Cu), a group III element, and a group VI element, wherein the quantum dots further include a halogen component selected from iodide ions, bromide ions, chloride ions, fluoride ions, and combinations thereof, wherein a molar ratio of the halogen component to Cu and the group III element is in a range of about 0.01 to about 0.5, and a FWHM of a photoluminescence spectrum of the quantum dots is 80 nm or less.

[0008] According to one or more embodiments, a method for preparing quantum dots includes: providing a metal precursor solution including copper halide and two group III element halides and a solvent; injecting a precursor of a group VI element into the metal precursor solution; and preparing quantum dots including copper, two group III elements, and a group VI element by reacting the metal precursor solution into which the precursor of the group VI element is injected; wherein the halogen components in the copper halide and the group III element halides are each independently selected from iodide ions, bromide ions, chloride ions, and fluoride ions, so that the quantum dots exhibit a photoluminescence spectrum, the photoluminescence spectrum has a maximum emission wavelength in the range of about 500 nm to about 750 nm and a FWHM of 80 nm or less, and the molar ratio of the halogen components of the quantum dots to copper and the group III element is in the range of about 0.01 to about 0.5.

[0009] According to one or more embodiments, an electronic device includes quantum dots. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The above and other aspects, features and advantages of certain embodiments will become more apparent from the following description in conjunction with the accompanying drawings, in which:

[0011] Figure 1 is a schematic cross-sectional view showing a structure of an electronic device according to an embodiment;

[0012] Figure 2 is a schematic cross-sectional view showing the structure of a light emitting device according to an embodiment of the present disclosure;

[0013] Figure 3 The CuInGaS of Comparative Test Examples 1 to 4 are shown. 2 A graph of the photoluminescence (PL) spectrum of quantum dots;

[0014] Figure 4 The graph shows the composition ratio (molar ratio) of Ga to In+Ga in quantum dots. Figure 3 The intensity and peak position of the PL spectrum of

[0015] Figure 5 CuInGaS of Test Examples 1 to 5 are shown. 2 PL spectra of quantum dots;

[0016] Figure 6 CuInGaS of Test Examples 6 to 9 are shown. 2 PL spectra of quantum dots;

[0017] Figure 7 is a graph showing the maximum emission wavelength and the full width at half maximum (FWHM) of PL spectra of Test Examples 6 to 9 for a set of metal precursors; and

[0018] FIG. 8A to FIG. 8C The CuInGaS of Test Examples 7 to 9 are shown respectively. 2 Transmission electron microscopy (TEM) image of quantum dots. DETAILED DESCRIPTION

[0019] Embodiments of the present invention will now be described in detail, and examples of embodiments are shown in the accompanying drawings, wherein the same reference numerals always refer to the same elements. In this regard, the present embodiment can have different forms, and should not be construed as being limited to the description set forth herein. Accordingly, the embodiments are described below only by reference to the accompanying drawings to explain aspects. As used herein, the term "and / or" includes any combination and all combinations of one or more related listed items. Such as "at least one (individual / kind) of ... ", when appearing after the column of an element (element), modify the column of the entire element (element), rather than modifying the single element (element) of the column.

[0020] Since the present disclosure can be applied to various changes and has various embodiments, specific embodiments will be shown in the drawings and described in detail in the detailed description. Figure 1 The effects and features of the present disclosure and methods for achieving the effects and features will become clear from the embodiments described in detail below. However, the present disclosure is not limited to the embodiments disclosed below and can be implemented in various forms.

[0021] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. When describing with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals, and their redundant description is omitted.

[0022] In the following examples, expressions such as "a", "an", and "the" used in the singular are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0023] In the following embodiments, it will be understood that terms such as “includes,” “comprising,” and “having” specify the presence of stated features or components but do not preclude the presence or addition of one or more other features or components.

[0024] In the following embodiments, it will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present.

[0025] In the drawings, the size of the components may be exaggerated or reduced for the convenience of description. For example, the size and thickness of the respective components shown in the drawings are arbitrarily shown for the convenience of description, and therefore one or more embodiments are not necessarily limited thereto.

[0026] As used herein, “Group II elements” may include Group IIA elements and Group IIB elements in the International Union of Pure and Applied Chemistry (“IUPAC”) periodic table, and examples of Group II elements may include magnesium (Mg), zinc (Zn), cadmium (Cd), mercury (Hg), and (Cn), but one or more embodiments are not limited thereto.

[0027] As used herein, “Group III elements” may include Group IIIA elements and Group IIIB elements in the IUPAC periodic table, and examples of Group III elements may include aluminum (Al), indium (In), gallium (Ga), thallium (Tl), and (Nh), but one or more embodiments are not limited thereto.

[0028] As used herein, “Group V elements” may include Group VA elements and Group VB elements in the IUPAC periodic table, and examples of Group V elements may include nitrogen (N), phosphorus (P), and arsenic (As), but one or more embodiments are not limited thereto.

[0029] As used herein, “Group VI elements” may include Group VIA elements and Group VIB elements in the IUPAC periodic table, and examples of Group VI elements may include oxygen (O), sulfur (S), selenium (Se), and tellurium (Te), but one or more embodiments are not limited thereto.

[0030]

Quantum dot

[0031] The quantum dots according to one embodiment include copper (Cu), a group III element, and a group VI element.

[0032] The quantum dots may also include a halogen component that is an iodide ion, a bromide ion, a chloride ion, a fluoride ion, or a combination thereof.

[0033] The molar ratio of the halogen component to copper (Cu) and the Group III element may be in the range of about 0.01 to about 0.5.

[0034] The full width at half maximum (FWHM) of the photoluminescence (PL) spectrum of the quantum dots may be 80 nm or less.

[0035] The main components of the quantum dots may be copper, group III elements, and group VI elements, and the halogen component may be derived from metal halides, which are metal precursors in the process of preparing the quantum dots.

[0036] In an embodiment, the group III element may be aluminum (Al), gallium (Ga), indium (In), thallium (Tl), (Nh) or any combination thereof.

[0037] In an embodiment, the quantum dots may include two Group III elements.

[0038] In an embodiment, the Group III element may include a combination of gallium (Ga) and indium (In).

[0039] In an embodiment, the Group VI element may be sulfur (S), selenium (Se), tellurium (Te), or any combination thereof.

[0040] In an embodiment, the Group VI element may be sulfur (S).

[0041] In an embodiment, the halogen component may include at least two selected from iodide ion, bromide ion, chloride ion, and fluoride ion.

[0042] In an embodiment, a halogen component may be present on the surface of the quantum dots.

[0043] In embodiments, a molar ratio of the halogen component to copper may be in a range of about 0.01 to about 0.5, about 0.02 to about 0.4, or about 0.1 to about 0.35.

[0044] In embodiments, the molar ratio of the halogen component to all Group III elements may be in a range of about 0.01 to about 0.7, about 0.02 to about 0.6, or about 0.1 to about 0.5.

[0045] In an embodiment, the quantum dots may be a quaternary system including a copper component.

[0046] In an embodiment, the quantum dots may include copper (Cu), indium (In), gallium (Ga), and sulfur (S).

[0047] According to an embodiment, relative to the total weight of the quantum dots, a weight ratio of copper may be in a range of about 10 wt % to about 40 wt %, a weight ratio of indium may be in a range of about 10 wt % to about 30 wt %, a weight ratio of gallium may be in a range of about 10 wt % to about 60 wt %, and a weight ratio of sulfur may be in a range of about 30 wt % to about 60 wt %.

[0048] In an embodiment, the quantum dots may be made of CuInGaS 2 express.

[0049] In an embodiment, the maximum emission wavelength of the PL spectrum of the quantum dot may be in the range of about 500 nm to about 750 nm. For example, the maximum emission wavelength of the PL spectrum of the quantum dot may be in the range of about 585 nm to about 750 nm or about 600 nm to about 720 nm.

[0050] According to an embodiment, the FWHM of the PL spectrum of the quantum dot may be 65 nm or less.

[0051] [Method for preparing quantum dots]

[0052] The method for preparing quantum dots according to an embodiment may include:

[0053] A metal precursor solution comprising copper halide, a halide of a group III element and a solvent is provided; a precursor of a group VI element is injected into the metal precursor solution; and quantum dots comprising copper, a group III element and a group VI element are prepared by reacting the metal precursor solution into which the precursor of the group VI element is injected.

[0054] The halides in the copper halide and the group III element halide may be each independently selected from iodide, bromide, chloride, and fluoride, such that the quantum dots exhibit a PL spectrum having a maximum emission wavelength in the range of about 500 nm to about 750 nm and a FWHM of 80 nm or less.

[0055] The molar ratio of the halide component to copper and the Group III element of the quantum dots prepared in this manner may be in the range of about 0.01 to about 0.5.

[0056] According to an embodiment, the group III element may be aluminum (Al), gallium (Ga), indium (In), thallium (Tl), (Nh) or any combination thereof.

[0057] According to an embodiment, the group III element halide may be AlI 3 , AlBr 3 、AlCl 3 , AlF 3 ,GaI 3 , GaBr 3 、GaCl 3 , GaF 3 ,InI 3 、InBr 3 、InCl 3 、InF 3 , TlI 3 ,TlBr 3 、TlCl 3 , TlF 3 、NhI 3 、NhBr 3 、NhCl 3 ,NhF 3 or any combination thereof.

[0058] According to an embodiment, the copper halide may be CuI, CuBr, CuCl, CuF, or any combination thereof.

[0059] According to an embodiment, the group III element halide may be provided as two group III element halides.

[0060] According to an embodiment, the two group III halides may each include a different group III element.

[0061] According to an embodiment, the two group III elements may include indium (In) and gallium (Ga).

[0062] According to an embodiment, the two group III element halides may be InI 3 、InBr 3 、InCl 3 or InF 3 , and GaI 3 , GaBr 3 、GaCl 3 or GaF 3 Any combination of .

[0063] According to an embodiment, at least two of the three halides among the copper halide and the two group III element halides may be different halides. According to an embodiment, when CuI is used as the copper halide, InI 3 and GaBr 3 ,InI 3 and GaCl 3 ,InI 3 and GaF 3 、InBr 3 and GaI 3 、InBr 3 and GaBr 3 、InBr 3 and GaCl 3 、InBr 3 and GaF 3 、InCl 3 and GaI 3 、InCl 3 and GaBr 3 、InCl 3 and GaCl 3 、InCl 3 and GaF 3 、InF 3 and GaI 3 、InF 3 and GaBr 3 、InF 3 and GaCl 3 or InF 3 and GaF 3According to an embodiment, when CuBr is used as the copper halide, InI 3 and GaI 3 ,InI 3 and GaBr 3 ,InI 3 and GaCl 3 ,InI 3 and GaF 3 、InBr 3 and GaI 3 、InBr 3 and GaCl 3 、InBr 3 and GaF 3 、InCl 3 and GaI 3 、InCl 3 and GaBr 3 、InCl 3 and GaCl 3 、InCl 3 and GaF 3 、InF 3 and GaI 3 、InF 3 and GaBr 3 、InF 3 and GaCl 3 or InF 3 and GaF 3 According to an embodiment, when CuCl is used as the copper halide, InI 3 and GaI 3 ,InI 3 and GaBr 3 ,InI 3 and GaCl 3 ,InI 3 and GaF 3 、InBr 3 and GaI 3 、InBr 3 and GaBr 3 、InBr 3 and GaCl 3 、InBr 3 and GaF 3 、InCl 3 and GaI 3 、InCl 3 and GaBr 3 、InCl 3 and GaF 3 、InF 3 and GaI3 、InF 3 and GaBr 3 、InF 3 and GaCl 3 or InF 3 and GaF 3 According to an embodiment, when CuF is used as the copper halide, InI 3 and GaI 3 ,InI 3 and GaBr 3 ,InI 3 and GaCl 3 ,InI 3 and GaF 3 、InBr 3 and GaI 3 、InBr 3 and GaBr 3 、InBr 3 and GaCl 3 、InBr 3 and GaF 3 、InCl 3 and GaI 3 、InCl 3 and GaBr 3 、InCl 3 and GaCl 3 、InCl 3 and GaF 3 、InF 3 and GaI 3 、InF 3 and GaBr 3 or InF 3 and GaCl 3 Can be used as two Group III halides.

[0064] For example, metal precursors for synthesizing quantum dots may include CuI, InCl 3 and GaI 3 、CuI、InI 3 and GaCl 3 、CuI、InCl 3 and GaCl 3 、CuBr、InI 3 and GaBr 3 、CuBr、InI 3 and GaCl 3 ,CuCl,InCl 3 and GaCl 3 , or CuCl, InF 3and GaFl 3 but one or more embodiments are not limited thereto.

[0065] The halogen component included in the quantum dot may exist on the surface of the quantum dot. In the process of preparing the quantum dot, the halogen component may be derived from a metal halide as a metal precursor.

[0066] According to an embodiment, the solvent may include 1-octadecene (ODE), trioctylamine (TOA), trioctylphosphine (TOP), or a combination thereof, but one or more embodiments are not limited thereto.

[0067] According to an embodiment, the Group VI element may be sulfur (S), selenium (Se), tellurium (Te), or any combination thereof.

[0068] According to an embodiment, the precursor of the Group VI element may be oleylamine (OLA) containing sulfur (S), selenium (Se) or tellurium (Te), ODE containing sulfur (S), selenium (Se) or tellurium (Te), or 1-dodecanethiol, but one or more embodiments are not limited thereto.

[0069] According to an embodiment, a maximum emission wavelength of a PL spectrum of the quantum dot may be in a range of about 585 nm to about 750 nm.

[0070] According to an embodiment, the FWHM of the PL spectrum may be 65 nm or less.

[0071] According to an embodiment, the quantum dots may include copper (Cu), indium (In), gallium (Ga), and sulfur (S). For example, the quantum dots may be made of CuInGaS 2 Represents quantum dots.

[0072] Quantum dots including III-V group elements or I-III-VI group elements can be used as environmentally friendly non-cadmium materials. Since InP quantum dots, which are representative III-V group quantum dots, have insufficient blue light absorptivity, the blue light absorptivity can be increased by increasing the thickness of the quantum dot film, but the quantum dot consumption may be large and the device efficiency may be reduced. Copper-based I-III-VI group quantum dots have high blue light absorptivity, but need to be synthesized using metal halide precursors to have a narrow emission FWHM. However, when a metal halide precursor including the same type of halide is used, even when the equivalence ratio of the precursor of the metal component is changed, the wavelength range of the PL spectrum that can be adjusted while the FWHM remains 80nm or less is also a very narrow range of about 30nm. In addition, in this case, the range at the reaction temperature at which the emission wavelength can be controlled may not be wide.

[0073] In the present disclosure, by changing the type of halide in the metal halide as a precursor of the metal component constituting the quantum dot, the emission wavelength can be adjusted more widely while maintaining a narrow FWHM. The emission wavelength of the quantum dot can be adjusted to a short emission wavelength by reducing the average atomic number of the halide used in the metal halide, and the emission wavelength of the quantum dot can be adjusted to a long emission wavelength by increasing the average atomic number of the halide.

[0074] In an embodiment, when indium iodide and gallium iodide are used as precursors to synthesize quantum dots including indium and gallium as group III elements, the gallium component in the quantum dots can be increased, and the emission color of the quantum dots can become close to green. In another embodiment, when indium chloride and gallium chloride are used as precursors to synthesize quantum dots including indium and gallium as group III elements, the indium component in the quantum dots can be increased, and the emission color of the quantum dots can become close to red. In another embodiment, when indium chloride and gallium iodide are used together as precursors, or when indium iodide and gallium chloride are used together as precursors, the quantum dots can emit a color in a region between green and red. It can be considered that the composition of each metal constituting the quantum dot and the size of the quantum dot are controlled by changing the type of halide in the metal halide.

[0075]

Electronic equipment

[0076] According to an embodiment, an electronic device including quantum dots may be provided.

[0077] Quantum dots can be included in various electronic devices. For example, the electronic device including quantum dots can be a light emitting device or an authentication device, etc.

[0078] An electronic device (e.g., a light emitting device or a display device) may further include a light emitting device, and i) a color filter, ii) a color conversion layer, or iii) a color filter and a color conversion layer. The color filter and / or the color conversion layer may be arranged in at least one direction of travel of the light emitted from the light emitting device. For example, the light emitted from the light emitting device may be blue light or white light. According to an embodiment, the light emitting device may include quantum dots. According to an embodiment, the color conversion layer may include quantum dots. The quantum dots may be, for example, the quantum dots described herein.

[0079] The electronic device may include a first substrate, the first substrate may include a plurality of sub-pixel regions, the color filter may include a plurality of color filter regions respectively corresponding to the plurality of sub-pixel regions, and the color conversion layer may include a plurality of color conversion regions respectively corresponding to the plurality of sub-pixel regions.

[0080] A pixel defining film may be disposed between the plurality of sub-pixel regions to define each sub-pixel region.

[0081] The color filter may further include a plurality of color filter regions and a light blocking pattern disposed between the plurality of color filter regions, and the color conversion layer may further include a plurality of color conversion regions and a light blocking pattern disposed between the plurality of color conversion regions.

[0082] The plurality of color filter regions (or the plurality of color conversion regions) may include a first region emitting a first color light, a second region emitting a second color light, and / or a third region emitting a third color light, and the first color light, the second color light, and / or the third color light may have different maximum emission wavelengths. For example, the first color light may be red light, the second color light may be green light, and the third color light may be blue light. For example, the plurality of color filter regions (or the plurality of color conversion regions) may include quantum dots. Specifically, the first region may include red quantum dots, the second region may include green quantum dots, and the third region may not include quantum dots. The quantum dots may be as defined herein. Each of the first region, the second region, and the third region may further include a scatterer.

[0083] For example, the light emitting device may emit a first light, the first region may absorb the first light to emit 1-1 color light, the second region may absorb the first light to emit 2-1 color light, and the third region may absorb the first light to emit 3-1 color light. In this case, the 1-1 color light, the 2-1 color light, and the 3-1 color light may have different maximum emission wavelengths. Specifically, the first color light may be blue light, the 1-1 color light may be red light, the 2-1 color light may be green light, and the 3-1 color light may be blue light.

[0084] In addition to the light emitting device described above, the electronic device may further include a thin film transistor. The thin film transistor may include a source electrode, a drain electrode and an active layer, and any one of the source electrode and the drain electrode may be electrically connected to any one of the first electrode and the second electrode of the light emitting device.

[0085] The thin film transistor may further include a gate electrode, a gate insulating film, and the like.

[0086] The active layer may include crystalline silicon, amorphous silicon, an organic semiconductor, an oxide semiconductor, or the like.

[0087] The electronic device may further include a sealing portion that seals the light-emitting device. The sealing portion may be disposed between the color filter and / or the color conversion layer and the light-emitting device. The sealing portion may emit light from the light-emitting device to the outside, and at the same time may prevent ambient air and moisture from penetrating into the light-emitting device. The sealing portion may be a sealing substrate including a transparent glass substrate or a plastic substrate. The above-mentioned sealing portion may be a thin film encapsulation layer including one or more organic layers and / or one or more inorganic layers. When the sealing portion is a thin film encapsulation layer, the electronic device may be flexible.

[0088] On the sealing portion, in addition to the color filter and / or color conversion layer, various functional layers may be additionally provided according to the use of the electronic device. Examples of the functional layer may include a touch screen layer and a polarization layer, etc. The touch screen layer may be a pressure-sensitive touch screen layer, a capacitive touch screen layer, or an infrared touch screen layer. For example, the authentication device may be a biometric authentication device that authenticates an individual by using biometric information of a living body (e.g., a fingertip or pupil, etc.).

[0089] In addition to the light emitting device described above, the authentication device may also include a biometric identification information collection method.

[0090] The electronic device can be applied to various displays, light sources, lighting equipment, personal computers (e.g., mobile personal computers), mobile phones, digital cameras, electronic organizers, electronic dictionaries, electronic game consoles, medical instruments (e.g., electronic thermometers, blood pressure meters, blood glucose meters, pulse measuring devices, pulse wave measuring devices, electrocardiogram displays, ultrasonic diagnostic equipment or endoscope displays), fish finders, various measuring instruments, meters (e.g., meters for vehicles, aircraft and ships) and projectors, etc.

[0091] [Reference Figure 1 describe】

[0092] According to an embodiment, there may be provided an electronic device including: a light source; and a color conversion member disposed on a path of light emitted from the light source, wherein quantum dots are included in the color conversion member.

[0093] Figure 1 is a schematic cross-sectional view showing the structure of an electronic device 200 according to the embodiment. Figure 1 The electronic device 200 may include a substrate 210 , a light source 220 disposed on the substrate, and a color conversion member 230 disposed on the light source 220 .

[0094] For example, the light source 220 may be a backlight unit (BLU) used in a liquid crystal display (LCD), a fluorescent lamp, a light emitting device, an organic light emitting device, a quantum dot light emitting device (QLED), or a combination thereof, but one or more embodiments are not limited thereto. The color conversion member 230 may be disposed in at least one traveling direction of light emitted from the light source 220.

[0095] At least one region in the color conversion member 230 of the electronic device 200 may include quantum dots, and the region may absorb light emitted from a light source to emit light having a maximum emission wavelength in the range of about 500 nm to about 750 nm.

[0096] In this case, the fact that the color conversion member 230 is disposed in at least one traveling direction of light emitted from the light source 220 does not exclude that other elements may be further included between the color conversion member 230 and the light source 220 .

[0097] For example, a polarizing plate, a liquid crystal layer, a light guide plate, a diffusion plate, a prism sheet, a microlens sheet, a brightness enhancement sheet, a reflective film, a color filter, or a combination thereof may be additionally disposed between the light source 220 and the color conversion member 230 .

[0098] As another example, a polarizing plate, a liquid crystal layer, a light guide plate, a diffusion plate, a prism sheet, a microlens sheet, a brightness enhancement sheet, a reflective film, a color filter, or a combination thereof may be additionally disposed on the color conversion member 230 .

[0099] As described above, the light emitted from the light source 220 may be converted into light while passing through the quantum dots in the color conversion member 230. For example, the quantum dots may absorb the first light emitted from the light source 220, and may emit visible light different from the first light. For example, the quantum dots may absorb the ultraviolet (UV) light emitted from the light source 220, and may emit visible light having a maximum emission wavelength of about 500nm to about 750nm. As another example, the quantum dots may absorb the blue light emitted from the light source 220, and may emit visible light having a maximum emission wavelength of about 500nm to about 750nm. Therefore, the color conversion member 230 including the quantum dots may be designed to absorb the ultraviolet light or blue light emitted from the light source 220 to emit light having an emission wavelength in a variety of color ranges.

[0100] For another example, the quantum dots may absorb blue light emitted from the light source 220 and may emit green light having a maximum emission wavelength of about 500 nm to about 570 nm. As another example, the quantum dots may absorb blue light emitted from the light source 220 and may emit red light having a maximum emission wavelength of about 630 nm to about 750 nm.

[0101] Therefore, the quantum dots or the color conversion member 230 including the quantum dots may absorb light emitted from the light source 220 to realize green light or red light at high brightness and high color purity.

[0102] Figure 1 The electronic device 200 shown in FIG. 2 may be one example of a device according to an embodiment, may have various known forms, and may additionally include various known components for this purpose.

[0103] According to another embodiment, the electronic device 200 may have a structure in which a light source, a light guide plate, a color conversion member, a first polarizing plate, a liquid crystal layer, a color filter, and a second polarizing plate are sequentially disposed.

[0104] According to another embodiment, the electronic device 200 may have a structure in which a light source, a light guide plate, a first polarizing plate, a liquid crystal layer, a second polarizing plate, and a color conversion member are sequentially disposed.

[0105] In the above embodiment, the filter may include a pigment or a dye.In the above embodiment, one of the first polarizing plate and the second polarizing plate may be a vertical polarizing plate, and the other may be a horizontal polarizing plate.

[0106]

Light-emitting device

[0107] Meanwhile, the quantum dots as described herein may be used as emitters. According to an embodiment, a light-emitting device may be provided, the light-emitting device comprising: a first electrode; a second electrode opposite to the first electrode; and an emission layer disposed between the first electrode and the second electrode and comprising quantum dots. The light-emitting device may further comprise a hole transport region disposed between the first electrode and the emission layer, an electron transport region disposed between the emission layer and the second electrode, or a combination thereof.

[0108] [Reference Figure 2 describe】

[0109] Figure 2 3 is a schematic cross-sectional view showing a structure of a light emitting device 300 according to an embodiment of the present disclosure. The light emitting device 300 may include a first electrode 310 , an intermediate layer 330 , and a second electrode 350 .

[0110] The intermediate layer 330 may be disposed on the first electrode 310. The intermediate layer 330 may include an emission layer.

[0111] The intermediate layer 330 may further include a hole transport region disposed between the first electrode 310 and the emission layer and an electron transport region disposed between the emission layer and the second electrode 350 .

[0112] In addition to the quantum dots, the intermediate layer 330 may further include a metal-containing compound such as an organic metal compound, various organic materials or inorganic materials, and the like.

[0113] The hole transport region and the electron transport region may include a hole transport material and / or an electron transport material commonly used in an organic light-emitting device or a QLED.

[0114] Meanwhile, the intermediate layer 330 may include i) two or more light emitting units sequentially stacked between the first electrode 310 and the second electrode 350, and ii) a charge generation layer disposed between the two light emitting units. When the intermediate layer 330 includes the light emitting units and the charge generation layer described above, the light emitting device 300 may be a tandem light emitting device.

[0115] The emission layer may be a single quantum dot layer or may have a structure in which two or more quantum dot layers are stacked.

[0116] The emissive layer may include quantum dots as described herein.

[0117] In addition to the quantum dots described herein, the emissive layer may also include quantum dots other than the quantum dots described herein.

[0118] In addition to the quantum dots described herein, the emission layer may also include a dispersion medium in which the quantum dots are dispersed in a naturally coordinated form. The dispersion medium may include an organic solvent, a polymer resin, or a combination thereof. Any transparent medium may be used as a dispersion medium as long as the transparent medium does not affect the optical properties of the quantum dots, does not deteriorate due to light, and does not absorb light. For example, the organic solvent may include toluene, chloroform, ethanol, octane, or a combination thereof, and the polymer resin may include an epoxy resin, a silicone resin, a polystyrene resin, an acrylate resin, or a combination thereof.

[0119] In an embodiment, the emission layer may be formed by applying an emission layer forming composition including quantum dots onto the hole transport region and volatilizing at least a portion of a solvent included in the emission layer forming composition.

[0120] For example, water, n-hexane, chloroform, toluene, octane, or the like may be used as the solvent included in the emission layer forming composition.

[0121] The emission layer-forming composition may be applied by using spin coating, casting, micro gravure coating, gravure printing, rod coating, roller coating, wire bar coating, dip coating, spray coating, screen printing, flexographic printing, offset printing, inkjet printing, or the like.

[0122] When the light emitting device 300 is a full-color light emitting device, the emission layer may include an emission layer emitting light having a different color for each individual sub-pixel.

[0123] For example, the emission layer may be patterned into a first color emission layer, a second color emission layer, and a third color emission layer for each individual sub-pixel. In this case, at least one of the emission layers may necessarily include quantum dots. Specifically, the first color emission layer may be a quantum dot emission layer including quantum dots, and the second color emission layer and the third color emission layer may each be an organic emission layer including an organic compound. Here, the first color to the third color may be different colors, and specifically, light having the first color to the third color may have different maximum emission wavelengths. The first color to the third color may be combined with each other to form white.

[0124] As another example, the emission layer may further include a fourth color emission layer. Various modifications may be made, wherein at least one of the first to fourth color emission layers is a quantum dot emission layer including quantum dots, and the remaining emission layers thereof are each an organic emission layer including an organic compound. Here, the first to fourth colors are different colors, and specifically, light having the first to fourth colors may have different maximum emission wavelengths. The first to fourth colors may be combined with each other to form white.

[0125] Alternatively, the light emitting device 300 may have a structure in which two or more emission layers emitting light having the same or different colors are stacked to contact or be spaced apart from each other. Various modifications may be made in which at least one of the two or more emission layers is a quantum dot emission layer including quantum dots, and the remaining emission layers thereof are organic emission layers including organic compounds. Specifically, the light emitting device 300 may include a first color emission layer and a second color emission layer, wherein the first color and the second color may be the same color or different colors. More specifically, both the first color and the second color may be green.

[0126] The emission layer may further include at least one selected from an organic compound and an inorganic compound in addition to the quantum dots.

[0127] Specifically, the organic compound may include a host and a dopant, and the host and the dopant may include hosts and dopants commonly used in organic light-emitting devices.

[0128] Hereinafter, quantum dots and methods of preparing quantum dots according to embodiments of the present disclosure will be described in more detail by way of examples.

[0129] [Test example]

[0130] CuInGaS 2 Synthesis of quantum dots

[0131] Comparative test example 1

[0132] 0.3 mmol of CuI and 0.6 mmol of InI 3 and 0.37 mmol of GaI 3 It was put into a three-necked flask, mixed with 10 ml of OLA and 10 ml of 1-ODE in the three-necked flask, and then degassed and stirred at a temperature of 120° C. for 30 minutes to prepare a reaction solution.

[0133] In nitrogen (N 2 ) atmosphere, 2.0 mmol of sulfur-OLA and 4.8 mmol of 1-dodecanethiol were added to the reaction solution, the temperature was raised to 230° C., maintained for 4 hours, and then cooled to room temperature to synthesize CuInGaS 2Quantum dots.

[0134] The synthesized CuInGaS 2 The quantum dots were diluted with toluene and precipitated with ethanol for purification.

[0135] Comparative Test Example 2 to Comparative Test Example 4

[0136] In addition to using CuI, InI 3 and GaI 3 The amount of 0.3mmol of CuI and 0.6mmol of InI 3 and 0.37 mmol of GaI 3 In addition, CuInGaS was synthesized and purified in the same manner as in Comparative Test Example 1. 2 Quantum dots.

[0137] Test Example 1 to Test Example 5

[0138] In addition to using the precursors (mol) shown in Table 2 as Cu precursors (CuX), In precursors (InY 3 ) and Ga precursor (GaZ 3 ) instead of using 0.3 mmol of CuI, 0.6 mmol of InI 3 and 0.37 mmol of GaI 3 In addition, CuInGaS was synthesized and purified in the same manner as in Comparative Test Example 1. 2 Quantum dots.

[0139] Test Example 6 to Test Example 9

[0140] In addition to using the precursors (mol) shown in Table 3 as Cu precursors (CuX), In precursors (InY 3 ) and Ga precursor (GaZ 3 ) instead of using 0.3 mmol of CuI, 0.6 mmol of InI 3 and 0.37 mmol of GaI 3 In addition, CuInGaS was synthesized and purified in the same manner as in Comparative Test Example 1. 2 Quantum dots.

[0141] Evaluation of quantum dot luminescence properties

[0142] For CuInGaS in Test Examples 1 to 9 and Comparative Test Examples 1 to 4 2Quantum dots, 0.2 ml of quantum dots were dispersed in 2.8 ml of toluene in a quartz cuvette, and the maximum emission wavelength and FWHM of the quantum dots were measured by using a PL spectrometer (FluoroMax manufactured by Horiba) and a UV-VIS spectrometer (Lambda365+ manufactured by PerkinElmer). In this case, the wavelength of the excitation light was 450 nm.

[0143] Figure 3 The CuInGaS of Comparative Test Examples 1 to 4 are shown. 2 A graph of the PL spectrum of quantum dots. Figure 4 is a graph showing the molar ratio of Ga to In+Ga in quantum dots. Figure 3 The intensity of the PL spectrum (PL intensity) and the peak position (PL peak position) of the PL spectrum of the comparative test examples 1 to 4 are shown in Table 1. The composition ratio of Ga to In+Ga is obtained by inductively coupled plasma (ICP) analysis of quantum dots. The intensity of the PL spectrum reflects the luminous efficiency. Table 1 shows the CuInGaS 2 Maximum emission wavelength of quantum dots and molar ratio of Ga to In+Ga. The molar ratio of Ga to In+Ga was obtained by performing inductively coupled plasma mass spectrometry (ICP-MS) analysis using a 7850 ICP-MS device (manufactured by Agilent technologies).

[0144] Figure 5 CuInGaS of Test Examples 1 to 5 are shown. 2 Table 2 shows the PL spectra of the CuInGaS quantum dots of Test Examples 1 to 5. 2 The maximum emission wavelength and FWHM of quantum dots and the molar ratio of halogen components to metal components. The halogen component is the sum of all halogen components present in the quantum dots, and the metal component is the sum of all metal components present in the quantum dots (ie, the sum of Cu, In and Ga).

[0145] Figure 6 CuInGaS of Test Examples 6 to 9 are shown. 2 Table 3 shows the PL spectra of the CuInGaS quantum dots of Test Examples 6 to 9. 2 The maximum emission wavelength and FWHM of quantum dots and the molar ratio of the halogen component to the metal component. Figure 7 is a graph showing the maximum emission wavelength and FWHM of PL spectra of Test Examples 6 to 9 for a set of metal precursors.

[0146] The molar ratio of the halogen component to the metal component was obtained by X-ray photoelectron spectroscopy (XPS) analysis using a Nexsa G2 (Thermofisher) equipment.

[0147]

Table 1

[0148]

[0149]

Table 2

[0150]

[0151]

[0152]

Table 3

[0153]

[0154] For the groups of Comparative Test Examples 1 to 4, refer to Figure 3 and Figure 4 And Table 1, CuInGaS 2 The molar ratio of Ga to In+Ga of quantum dots ranges from 0.38 to 0.78, but the maximum emission wavelength of the PL spectrum ranges from 30 nm to 553 nm to 583 nm. At the same time, as the molar ratio of Ga to In+Ga increases, the intensity of the PL spectrum first increases to 0.67 and then decreases to 0.78. As the molar ratio of Ga to In+Ga increases, the maximum emission wavelength increases to 0.56 and then decreases.

[0155] For the groups of Test Examples 1 to 5, refer to Figure 5 and Table 2, where CuI, InI 3 and GaI 3 The maximum emission wavelength of the PL spectrum of the quantum dots of Test Example 1 used as metal precursors is 506 nm, and CuCl, InF 3 and GaF 3 The maximum emission wavelength of the PL spectrum of the quantum dots of Test Example 5 used as a metal precursor is 723 nm, so the range of the maximum emission wavelength is 217 nm. In the group of Test Examples 1 to 5, the maximum emission wavelength range of the quantum dots is 7 times wider or more than the range of the maximum emission wavelength of the PL spectrum of 30 nm in the group of Comparative Test Examples 1 to 4.

[0156] Reference Figure 6 and Figure 7 And Table 3, for the group of test examples 6 to 9, where CuI, InI 3 and GaI 3The maximum emission wavelength of the PL spectrum of the quantum dots of Test Example 6 used as metal precursors is 540 nm, in which CuI, InCl 3 and GaCl 3 The maximum emission wavelength of the PL spectrum of the quantum dots of Test Example 9 used as a metal precursor is 620 nm, so that the range of the maximum emission wavelength is 80 nm. The range of the maximum emission wavelength of 80 nm is twice as wide or more as the maximum emission wavelength range of 30 nm in the group of Comparative Test Examples 1 to Comparative Test Examples 4. In addition, referring to Figure 7 In Test Example 6, when all three metal precursors use iodine as the halogen component, the wavelength of the emission peak is the shortest, and as the number of metal precursors including chlorine as the halogen component increases, the wavelength of the emission peak becomes significantly longer. This trend can also be observed in Test Examples 1 to 5. Referring again to Figure 5 As shown in Table 1, as the amount of metal halides including halides having lower atomic numbers increases, the maximum emission wavelength becomes longer.

[0157] Meanwhile, referring to Table 2 and Table 3, in the CuInGaS 2 Halogen components were detected in the quantum dots and were considered to be derived from metal halide precursors. XPS measurements showed that the halogen components were present on the surface of the quantum dots.

[0158] FIG. 8A to FIG. 8C The CuInGaS of Test Examples 7 to 9 are shown respectively. 2 Transmission electron microscopy (TEM) images of quantum dots. TEM images were obtained using a JEM-ARM300F2 instrument (manufactured by JEOL Ltd.). FIG. 8A to FIG. 8C The upper right graph of is a histogram showing the distribution of particle sizes analyzed by TEM. The X-axis in the graph represents the particle size, and the Y-axis represents the number of particles. FIG. 8A to FIG. 8C , the size of the quantum dots gradually increases in the order of test example 7 to test example 9.

[0159] It can be seen from the PL spectra of Comparative Test Examples 1 to Comparative Test Examples 4, Test Examples 1 to Test Examples 5, and Test Examples 6 to Test Examples 9 that the PL spectra for synthesizing CuInGaS 2 The halogen species in the metal precursor of the quantum dots can widely tune the emission wavelength of the quantum dots while having a FWHM of 80 nm or less.

[0160] Quantum dots can have desired emission wavelengths over a wide range while maintaining a narrow FWHM.

[0161] It should be understood that the embodiments described herein should be considered as illustrative only and not for limiting purposes. The description of features or aspects in each embodiment should generally be considered as applicable to other similar features or aspects in other embodiments. Although one or more embodiments have been described with reference to the accompanying drawings, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope defined by the appended claims.

Claims

1. A quantum dot, wherein The quantum dots include copper, group III elements and group VI elements, Wherein, the quantum dots further include a halogen component selected from iodide ions, bromide ions, chloride ions, fluoride ions and combinations thereof, wherein the molar ratio of the halogen component to the copper and the group III element is in the range of 0.01 to 0.5, and The full width at half maximum of the photoluminescence spectrum of the quantum dots is 80 nm or less.

2. The quantum dot according to claim 1, wherein The group III elements are aluminum, gallium, indium, thallium, or any combination thereof.

3. The quantum dot according to claim 1, wherein The Group VI element is sulfur, selenium, tellurium or any combination thereof.

4. The quantum dot according to claim 1, wherein The halogen component includes at least two selected from iodide ion, bromide ion, chloride ion and fluoride ion.

5. The quantum dot according to claim 1, wherein The molar ratio of the halogen component to the copper is in the range of 0.02 to 0.

4.

6. The quantum dot according to claim 1, wherein The molar ratio of the halogen component to the Group III element is in the range of 0.02 to 0.

5.

7. The quantum dot according to claim 1, wherein The quantum dots include copper, indium, gallium and sulfur.

8. The quantum dot according to claim 7, wherein Relative to the total weight of the quantum dots, the weight ratio of copper is in the range of 10wt% to 40wt%, the weight ratio of indium is in the range of 10wt% to 30wt%, the weight ratio of gallium is in the range of 10wt% to 60wt%, and the weight ratio of sulfur is in the range of 30wt% to 60wt%.

9. The quantum dot according to claim 1, wherein The maximum emission wavelength of the photoluminescence spectrum is in the range of 500 nm to 750 nm.

10. The quantum dot according to claim 1, wherein The maximum emission wavelength of the photoluminescence spectrum is in the range of 585 nm to 750 nm.

11. The quantum dot according to claim 1, wherein The full width at half maximum of the photoluminescence spectrum is 65 nm or less.

12. A method for preparing quantum dots, wherein: The method comprises: providing a metal precursor solution including copper halide, a group III element halide, and a solvent; injecting a precursor of a Group VI element into the metal precursor solution; and preparing quantum dots including copper, group III elements, and group VI elements by reacting the metal precursor solution into which the precursor of the group VI element is injected; wherein the halogen components in the copper halide and the group III element halide are each independently selected from iodide ions, bromide ions, chloride ions and fluoride ions, so that the quantum dots exhibit a photoluminescence spectrum having a maximum emission wavelength in the range of 500 nm to 750 nm and a half-maximum full width of 80 nm or less, and A composition ratio of the halogen component of the quantum dots to the copper and the group III element is in the range of 0.01 to 0.

5.

13. The method according to claim 12, wherein: The group III element halides include two group III element halides containing different group III elements.

14. The method according to claim 13, wherein: At least two of the halides of each of the copper halide and the two Group III element halides are different halides.

15. The method according to claim 13, wherein: The two group III element halides are indium halide and gallium halide, respectively, and The Group VI element is sulfur, selenium, tellurium or any combination thereof.

16. The method according to claim 12, wherein: The maximum emission wavelength of the photoluminescence spectrum of the quantum dots is in the range of 585 nm to 750 nm.

17. The method according to claim 12, wherein: The full width at half maximum of the photoluminescence spectrum is 65 nm or less.

18. The method according to claim 12, wherein: The quantum dots include copper, indium, gallium and sulfur.

19. An electronic device, wherein: The electronic device comprises the quantum dot according to any one of claims 1 to 11.

20. The electronic device according to claim 19, wherein: The electronic device further comprises: Light source; and a color conversion member disposed on a path of light emitted from the light source; Wherein, the quantum dots are contained in the color conversion component.

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