Quantum dot and method for preparing the same

Abstract

Methods for preparing quantum dots and quantum dots are provided. The method for preparing quantum dots includes: supplying a first mixture including a first precursor including gallium oleate, a second precursor including indium oleate, and a third precursor including sulfur atoms; forming a second mixture by adding a first solvent to the first mixture; and forming a fourth mixture by adding a third mixture comprising copper to the second mixture, the fourth mixture comprising a core comprising copper atoms, indium atoms, gallium atoms, and sulfur atoms.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0120700 filed in the Korean Intellectual Property Office on September 11, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] Embodiments of the present disclosure relate to quantum dots and methods for preparing the quantum dots, and, for example, to quantum dots having improved color reproducibility and light absorption characteristics and methods for preparing the quantum dots. Background Art

[0004] Various display devices are being developed for multimedia devices such as televisions, mobile phones, tablet computers, navigation systems, and / or game consoles. In the display devices, so-called self-luminous type or self-luminous type display elements are used, which have an emission material containing an organic compound emit light, thereby realizing display (e.g., display of an image).

[0005] In addition, in order to improve the color reproducibility of a display device, a light-emitting element using quantum dots as an emission material is being developed or promoted, and it is desired or necessary to improve the life span and emission efficiency of the light-emitting element using quantum dots. Summary of the invention

[0006] An aspect of one or more embodiments of the present disclosure is directed to a quantum dot having improved color reproducibility and light absorption characteristics by including a core containing copper, gallium, indium, and sulfur.

[0007] Aspects of one or more embodiments of the present disclosure also relate to a method for preparing quantum dots having improved color reproducibility and light absorption characteristics by including a core containing copper, gallium, indium, and sulfur.

[0008] 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.

[0009] One or more embodiments of the present disclosure provide a method for preparing quantum dots, the method comprising: supplying a first mixture, the first mixture comprising a first precursor (or precursor, precursor) comprising gallium oleate, a second precursor comprising indium oleate, and a third precursor comprising sulfur atoms; forming a second mixture by adding a first solvent to the first mixture; and forming a fourth mixture comprising a core by adding a third mixture comprising copper to the second mixture, the core comprising the fourth mixture comprising copper atoms, indium atoms, gallium atoms and sulfur atoms.

[0010] In one or more embodiments, the core may have a diameter of about 3 nm to about 6 nm.

[0011] In one or more embodiments, the first solvent may include at least one selected from 1-octadecene and trioctylamine.

[0012] In one or more embodiments, the method may further include reacting the fourth mixture at a first temperature for about 5 minutes to about 15 minutes, and the first temperature may be about 250°C to about 350°C.

[0013] In one or more embodiments, in the second mixture, the mole number of gallium atoms may be greater than the mole number of indium atoms.

[0014] In one or more embodiments, the method may further include forming a first shell around (eg, covering) the core by reacting a fourth precursor containing zinc oleate and a fifth precursor containing a sulfur atom.

[0015] In one or more embodiments, in the quantum dots, the mass of gallium atoms may be approximately 5 wt% (e.g., weight % or mass %) to approximately 50 wt% relative to the total mass of 100 wt% quantum dots; and in the quantum dots, the mass ratio of the gallium atoms relative to the mass of the quantum dots may be greater than the mass ratio of indium atoms relative to the mass of the quantum dots.

[0016] In one or more embodiments, the first solvent may include 1-octadecene and trioctylamine; and the method may include: degassing the trioctylamine at about 120° C. prior to the forming of the first shell.

[0017] In one or more embodiments, the forming of the first shell may be performed at a second temperature for about 15 minutes to about 25 minutes; and the second temperature may be about 280°C to about 350°C.

[0018] In one or more embodiments, a molar ratio of the fourth precursor to the fifth precursor may be approximately 1:1.

[0019] In one or more embodiments, during the forming of the first shell, the fourth precursor and the fifth precursor may be independently provided in an amount of about 0.4 mmol to about 1.6 mmol.

[0020] In one or more embodiments, the first shell has a thickness of about 0.5 nm to about 3 nm.

[0021] In one or more embodiments, the method may further include forming a second shell around (eg, covering) the first shell by adding a first element precursor and a second element precursor to a first particle including the core and the first shell.

[0022] In one or more embodiments, the second shell may include at least one selected from ZnSe, ZnS, ZnTe, ZnO, ZnMg, ZnMgSe, ZnMgS, ZnMgAl, GaSe, GaTe, GaP, GaAs, GaSb, InAs, InSb, AlP, AlAs, AlSb, MnS, MnSe, MgS and MgSe.

[0023] In one or more embodiments, the second shell may have a thickness of about 0.5 nm to about 3 nm.

[0024] In one or more embodiments, the thickness of the second shell may be greater than the thickness of the first shell.

[0025] In one or more embodiments of the present disclosure, a quantum dot includes: a core comprising copper atoms, indium atoms, gallium atoms, and sulfur atoms, and a first shell surrounding the core (e.g., covering the core) and comprising zinc atoms and sulfur atoms, wherein the core has a diameter of approximately 3 nm to approximately 6 nm.

[0026] In one or more embodiments, the mass of the gallium atoms may be approximately 5 wt% (e.g., weight % or mass %) to approximately 50 wt% relative to 100 wt% of the total mass of the quantum dots; and the mass ratio of the gallium atoms relative to the mass of the quantum dots may be greater than the mass ratio of the indium atoms relative to the mass of the quantum dots.

[0027] In one or more embodiments, the quantum dot may also include: a second shell, around the first shell (for example, covering the first shell), and containing at least one selected from ZnSe, ZnS, ZnTe, ZnO, ZnMg, ZnMgSe, ZnMgS, ZnMgAl, GaSe, GaTe, GaP, GaAs, GaSb, InAs, InSb, AlP, AlAs, AlSb, MnS, MnSe, MgS and MgSe.

[0028] In one or more embodiments, the thickness of the second shell may be greater than the thickness of the first shell. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated into and constitute a part of this specification. The accompanying drawings illustrate embodiments of the present disclosure and together with the specification are used to explain the principles of the present disclosure. In the accompanying drawings:

[0030] Figure 1 is a perspective view of an electronic device according to one or more embodiments of the present disclosure;

[0031] Figure 2 is an exploded perspective view of an electronic device according to one or more embodiments of the present disclosure;

[0032] Figure 3 According to one or more embodiments of the present disclosure, Figure 1 A cross-sectional view of the display device taken along line II' in FIG.

[0033] Figure 4 is a cross-sectional view of a light emitting element according to one or more embodiments of the present disclosure;

[0034] Figure 5 is a view schematically showing the structure of a quantum dot according to one or more embodiments of the present disclosure;

[0035] Figure 6 is a view schematically showing the structure of a quantum dot according to one or more embodiments of the present disclosure;

[0036] Figure 7 is an enlarged plan view showing a portion of a display device according to one or more embodiments of the present disclosure;

[0037] Figure 8 According to one or more embodiments of the present disclosure, Figure 7 A cross-sectional view of the display device taken along line II-II';

[0038] Fig. 9 According to one or more embodiments of the present disclosure, Figure 7 A cross-sectional view of the display device taken along line II-II';

[0039] Fig.10 is a flow chart showing a method for preparing quantum dots according to one or more embodiments of the present disclosure;

[0040] Fig.11 shows the absorbance and emission spectra of quantum dots according to Example 1; and

[0041] Fig.12 Absorbance spectra of quantum dots according to Example 1 and Comparative Example 2 are shown. DETAILED DESCRIPTION

[0042] The present disclosure can be modified in a variety of optional forms, and therefore specific embodiments will be shown in the drawings and described in more detail. However, it should be understood that it is not intended to limit the present disclosure to the specific form disclosed, but is intended to cover all modifications, equivalents and alternatives that fall within the spirit and scope of the present disclosure.

[0043] Hereinafter, example embodiments will be described in more detail with reference to the accompanying drawings. However, the present disclosure may be implemented in a variety of different forms and should not be construed as being limited to the embodiments shown herein. On the contrary, these embodiments are provided as examples so that the present disclosure will be thorough and complete and will fully convey the aspects and features of the present disclosure to those skilled in the art. Therefore, processes, elements, and techniques that are not necessary for a person of ordinary skill in the art to fully understand the aspects and features of the present disclosure may not be described.

[0044] It will be understood that when an element (such as a region, layer, film, area, or portion) is referred to as being "on," "connected to," or "engaged to" another element, the element can be directly on, directly connected to, or engaged to the other element, or one or more intervening elements may be present. Additionally, it will be understood that when an element is referred to as being "between" two elements, the element can be the only element between the two elements, or one or more intervening elements may also be present.

[0045] Unless otherwise specified, the same reference numerals refer to the same elements throughout the drawings and written descriptions, and therefore, repeated descriptions thereof may not be provided. In addition, in the drawings, the thickness, ratio, and size of the elements may be exaggerated to effectively describe the technical content.

[0046] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0047] It will be understood that, although the terms "first", "second", "third", etc. may be used to describe various elements, components, regions, layers and / or parts in this article, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the spirit and scope of the present disclosure, the first element, first component, first region, first layer or first part discussed below may be referred to as the second element, second component, second region, second layer or second part.

[0048] As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0049] For ease of explanation, spatially relative terms such as "on", "below", "below", "below", "above", and "on" may be used herein to describe the relationship of an element or feature to another element (or elements) or feature (or features) as shown in the drawings. It will be understood that, in addition to the orientations depicted in the drawings, the spatially relative terms are also intended to cover different orientations of the device in use or operation. For example, if the device is flipped in the drawings, an element described as "below", "under", or "below" other elements or features will then be oriented as "above" other elements or features. Therefore, the example terms "below" and "below" may include both above and below orientations. In addition, the device may be oriented in other ways (e.g., rotated 90 degrees or at other orientations), and the spatially relative terms used herein are interpreted accordingly.

[0050] It should also be understood that the terms “comprises, comprising,” “includes, including,” “have, having,” and “contain, containing” when used in this specification indicate the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0051] Unless it is obvious from the present disclosure, when preceding / following a list of elements, expressions such as “at least one of…”, “a plurality of…”, “one of…” and other prepositional phrases should be understood to include a disjunctive meaning if they are written as a connected list, and vice versa. For example, the expressions “at least one of a, b, and c”, and “one selected from the group consisting of a, b, and c”, “at least one selected from a, b, and c”, “at least one among a, b, and c”, and “one among a, b, and c”, “at least one of a to c” mean only a, only b, only c, both a and b, both a and c, both b and c, all of a, b, and c, or variations thereof.

[0052] As used herein, when a portion of an element such as a layer, a film, a region, and a plate is referred to as being “directly disposed” on another portion, there is no intervening portion such as a layer, a film, a region, and a plate between the portion such as a layer, a film, a region, and a plate and the other portion. For example, two layers or two members “directly disposed” may mean that the two layers or two members are disposed without using an additional member interposed therebetween.

[0053] As used herein, "Group" refers to a Group of the IUPAC Periodic Table of the Elements.

[0054] As used herein, "Group I elements" may include Group IA elements and Group IB elements. For example, the Group I element may be copper (Cu), but is not limited thereto.

[0055] As used herein, "Group II elements" may include Group IIA elements and Group IIB elements. For example, the Group II element may be magnesium (Mg) or zinc (Zn), but is not limited thereto.

[0056] As used herein, "Group III elements" may include Group IIIA elements and Group IIIB elements. For example, the Group III elements may be aluminum (Al), indium (In), gallium (Ga), but are not limited thereto.

[0057] As used herein, "Group V elements" may include Group VA elements and Group VB elements. For example, the Group V element may be phosphorus (P), arsenic (As), or antimony (Sb), but is not limited thereto.

[0058] As used herein, "Group VI elements" may include Group VIA elements and Group VIB elements. For example, the Group VI element may be oxygen (O), sulfur (S), selenium (Se), or tellurium (Te), but is not limited thereto.

[0059] As used herein, the terms "use," "using," and "used" may be considered synonymous with "utilize," "utilizing," and "utilized," respectively.

[0060] In the present disclosure, when the particle is spherical, "diameter" means the particle diameter or the average particle diameter, and when the particle is non-spherical, "diameter" means the major axis length or the average major axis length. The diameter of the particle can be measured using a scanning electron microscope or a particle size analyzer. As a particle size analyzer, for example, a HORIBA, LA-950 laser particle size analyzer can be used. When the size of the particle is measured using a particle size analyzer, the average particle diameter is referred to as D50. D50 refers to the average diameter (or size) of the particles whose cumulative volume corresponds to 50 vol% in a particle size distribution (e.g., cumulative distribution), and refers to the value of the particle size corresponding to 50% starting from the smallest particle when the total number of particles is 100% in a distribution curve accumulated in the order of the smallest particle size to the largest particle size.

[0061] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure belongs. In addition, unless explicitly defined as such herein, terms (such as those defined in general dictionaries) should be interpreted as having a meaning consistent with the context of the relevant technology and / or the meaning in this specification, and should not be interpreted in an idealized or overly formal sense.

[0062] Hereinafter, quantum dots, and a light emitting element and a display device including the same according to one or more embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0063] Figure 1 is a perspective view of an electronic device EA according to one or more embodiments of the present disclosure. Figure 2 is an exploded perspective view of an electronic device EA according to one or more embodiments of the present disclosure. Figure 3 According to one or more embodiments of the present disclosure, Figure 1 sectional view of the display device DD taken along line II' in FIG. Figure 4 is a cross-sectional view of a light emitting element ED according to one or more embodiments of the present disclosure.

[0064] Reference Figure 1 and Figure 2 In one or more embodiments, the electronic device EA may be a large electronic device, such as a television, a monitor, or an outdoor billboard. In one or more embodiments, the electronic device EA may be a small or medium-sized electronic device, such as a personal computer (e.g., a notebook computer, a tablet computer), a personal digital assistant, a car navigation unit, a game console, a smart phone, and / or a camera. These devices are presented as examples only, and other electronic devices may be employed as long as they do not depart from the spirit and scope of the present disclosure. Figure 1 , for ease of description, a smart phone is shown as an example of the electronic device EA.

[0065] The electronic device EA may include a display device DD and a housing HAU. The display device DD may display an image IM through a display surface IS, and a user may observe an image provided through a transmission area TA corresponding to a front surface FS of the electronic device EA. The image IM may include a static image and a dynamic image. Figure 1 , the front surface FS is shown to be parallel to a plane defined by a first direction DR1 and a second direction DR2 intersecting the first direction DR1. However, this is shown only as an example, and in one or more embodiments, the front surface FS of the electronic device EA may have a curved shape.

[0066] The normal direction of the front surface FS of the electronic device EA (e.g., the direction perpendicular to the front surface FS) is represented by the third direction DR3, and for example, the normal direction may be the direction in which the image IM is displayed, or may be the thickness direction of the electronic device EA. The front surface (or top surface) and the rear surface (or bottom surface) of each member may be separated by the third direction DR3.

[0067] The fourth direction DR4 (see for example Figure 7 ) may be a direction between the first direction DR1 and the second direction DR2. The fourth direction DR4 may be located on a plane parallel to a plane defined by the first direction DR1 and the second direction DR2 (for example, in a plan view). However, the directions indicated by the first direction DR1, the second direction DR2, the third direction DR3, and the fourth direction DR4 are relative concepts and may be changed to other directions.

[0068] In one or more embodiments, the electronic device EA may include a foldable display device including a folding area and a non-folding area, or a bendable display device including at least one bending portion.

[0069] The electronic device EA may include a display device DD and a housing HAU. In the electronic device EA, the front surface FS may correspond to the front surface of the display device DD and to the front surface of the window WP. Therefore, the same reference numeral FS is used for the front surface of the electronic device EA, the front surface of the display device DD, and the front surface of the window WP.

[0070] The housing HAU may house the display device DD. The housing HAU may be arranged to cover the display device DD so that the top surface, which is the display surface IS of the display device DD, is exposed. The housing HAU may cover the side surface and the bottom surface of the display device DD, and the entire top surface may be exposed. However, the present disclosure is not limited thereto, and the housing HAU may cover a portion of the top surface as well as the side surface and the bottom surface of the display device DD.

[0071] In the electronic device EA according to one or more embodiments, the window WP may include an optically transparent insulating material. The window WP may include a transmissive area TA and a frame area BZA. The front surface FS of the window WP including the transmissive area TA and the frame area BZA corresponds to the front surface FS of the electronic device EA.

[0072] exist Figure 1 and Figure 2 , the transmission area TA is shown as a rectangular shape with rounded corners in a plan view. However, this is shown only as an example, and the transmission area TA may have one or more suitable shapes in a plan view, and is not limited to any one embodiment.

[0073] The transmission area TA may be an optically transparent area. The frame area BZA may have a relatively lower light transmittance than the transmission area TA. The frame area BZA may have a set or predetermined color. The frame area BZA may be adjacent to the transmission area TA and around the transmission area TA (e.g., surrounding the transmission area TA). The frame area BZA may define the shape of the transmission area TA. However, the present disclosure is not limited thereto, and the frame area BZA may be arranged adjacent to only one or more sides of the transmission area TA, and some portions may not be provided.

[0074] The display device DD may be arranged below the window WP. As used herein, the term "below" refers to a direction opposite to a direction in which the display device DD provides the image IM.

[0075] In one or more embodiments, the display device DD may be a structure that generates an image IM. The image IM generated from the display device DD is displayed in the display surface IS and is observed by the user from the outside through the transmission area TA. The display device DD may include a display area DA and a non-display area NDA. The display area DA may be an area activated in response to an electrical signal. The non-display area NDA may be an area covered by a border area BZA. The non-display area NDA is adjacent to the display area DA. The non-display area NDA may be around the display area DA (e.g., surrounding the display area DA).

[0076] Reference Figure 3 , the display device DD may include a display panel DP and a light control layer PP. The display panel DP may include a display element layer DP-EL. The display element layer DP-EL includes a light emitting element ED (see, for example, Figure 4 ).

[0077] For example, the light control layer PP may be disposed on the display panel DP to control external light on the display panel DP by reflecting the external light. The light control layer PP may include, for example, a polarization layer or a color filter layer.

[0078] In the display panel DP according to one or more embodiments, the display panel DP may be a light-emitting type or luminescent display panel. For example, the display panel DP may be a quantum dot emission display panel including quantum dot light-emitting elements. However, the present disclosure is not limited thereto.

[0079] The display panel DP may include a base substrate BS, a circuit layer DP-CL disposed on the base substrate BS, and a display element layer DP-EL disposed on the circuit layer DP-CL.

[0080] The base substrate BS may be a member that provides a base surface on which the circuit layer DP-CL is arranged. The base substrate BS may be a glass substrate, a metal substrate, and / or a plastic substrate, etc. However, the present disclosure is not limited thereto, and the base substrate BS may be an inorganic layer, an organic layer, or a composite material layer. The base substrate BS may be a flexible substrate that is easy to bend or fold.

[0081] In one or more embodiments, the circuit layer DP-CL may be arranged on the base substrate BS, and the circuit layer DP-CL may include a plurality of transistors. The transistors may each include a control electrode, an input electrode, and an output electrode. For example, the circuit layer DP-CL may include a switch transistor and a driving transistor for driving the light emitting element ED of the display element layer DP-EL.

[0082] Reference Figure 4 , the light emitting element ED according to one or more embodiments may include a first electrode EL1, a second electrode EL2 facing the first electrode EL1, and a plurality of functional layers disposed between the first electrode EL1 and the second electrode EL2 and including an emission layer EML.

[0083] The plurality of functional layers may include a hole transport region HTR disposed between the first electrode EL1 and the emission layer EML and an electron transport region ETR disposed between the emission layer EML and the second electrode EL2. In one or more embodiments, a capping layer may be further disposed on the second electrode EL2.

[0084] The hole transport region HTR and the electron transport region ETR may each include a plurality of functional sublayers. For example, the hole transport region HTR may include a hole injection layer HIL and a hole transport layer HTL as functional sublayers, and the electron transport region ETR may include an electron injection layer EIL and an electron transport layer ETL as functional sublayers. However, the present disclosure is not limited thereto, and the hole transport region HTR may also include an electron blocking layer, etc., as a functional sublayer, and the electron transport region ETR may also include a hole blocking layer, etc., as a functional sublayer.

[0085] In the light emitting element ED according to one or more embodiments, the first electrode EL1 has conductivity (eg, is a conductor). The first electrode EL1 may be formed of a metal alloy or a conductive compound. The first electrode EL1 may be an anode. The first electrode EL1 may be a pixel electrode.

[0086] In the light-emitting element ED according to one or more embodiments, the first electrode EL1 may be a reflective electrode. However, the present disclosure is not limited thereto. For example, the first electrode EL1 may be a transmissive electrode and / or a semi-transmissive and semi-reflective electrode, etc. When the first electrode EL1 is a semi-transmissive and semi-reflective electrode or a reflective electrode, the first electrode EL1 may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, their (e.g., any suitable) compounds and / or their (e.g., any suitable) mixtures (e.g., mixtures of Ag and Mg), or materials having a multilayer structure such as LiF / Ca or LiF / Al. In one or more embodiments, the first electrode EL1 may have a multilayer structure including a reflective film or a semi-transmissive and semi-reflective film each formed of the materials described above and a transparent conductive film formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO) and / or indium tin zinc oxide (ITZO), etc. For example, the first electrode EL1 may be a multi-layered metal film, and may be a structure of ITO / Ag / ITO in which metal films are stacked.

[0087] The hole transport region HTR is provided on the first electrode EL1. The hole transport region HTR may include a hole injection layer HIL and / or a hole transport layer HTL, etc. In one or more embodiments, in addition to the hole injection layer HIL and the hole transport layer HTL, the hole transport region HTR may also include at least one selected from a hole buffer layer and an electron blocking layer. The hole buffer layer compensates for the resonance distance according to the wavelength of the emitted light, thereby improving the luminous efficiency. For the material contained in the hole buffer layer, the material that can be contained in the hole transport region HTR can be used. The electron blocking layer is used to prevent or substantially prevent electrons from being injected from the electron transport region ETR into the hole transport region HTR.

[0088] The hole transport region HTR may have a single-layer structure formed of a single material, a single-layer structure formed of a plurality of different materials, or a multilayer structure having a plurality of layers formed of different materials. For example, the hole transport region HTR may have a single-layer structure formed of different materials, or may have a multilayer structure in which a plurality of layers are sequentially stacked from the first electrode EL1, such as a hole injection layer HIL / hole transport layer HTL, a hole injection layer HIL / hole transport layer HTL / hole buffer layer, a hole injection layer HIL / hole buffer layer, a hole transport layer HTL / hole buffer layer, and / or a hole injection layer HIL / hole transport layer HTL / electron blocking layer. However, the present disclosure is not limited thereto.

[0089] The hole transport region HTR may be formed using one or more suitable methods, such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) method, inkjet printing, laser printing and / or laser induced thermal imaging (LITI) method.

[0090] The hole injection layer HIL may include, for example, a phthalocyanine compound such as copper phthalocyanine, N,N'-diphenyl-N,N'-bis-[4-(phenyl-m-tolyl-amino)-phenyl]-biphenyl-4,4'-diamine (DNTPD), 4,4',4"-[tris(3-methylphenyl)phenylamino]triphenylamine (m-MTDATA), 4,4',4"-tris(N,N-diphenylamino)triphenylamine (TDATA), 4,4',4"-tris{N,-(2-naphthyl)-N-phenylamino}-triphenylamine (2-TNATA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonic acid) salt) (PEDOT / PSS), polyaniline / dodecylbenzenesulfonic acid (PANI / DBSA), polyaniline / camphorsulfonic acid (PANI / CSA), polyaniline / poly(4-styrenesulfonate) (PANI / PSS), N,N'-di(naphthalene-1-yl)-N,N'-diphenylbenzidine (NPD), triphenylamine-containing polyetherketone (TPAPEK), 4-isopropyl-4'-methyldiphenyliodonium [tetrakis(pentafluorophenyl)borate] and / or dipyrazino[2,3-f:2',3'-h]quinoxaline-2,3,6,7,10,11-hexanitrile (HAT-CN), etc.

[0091] The hole transport layer HTL may include suitable conventional materials in the art. For example, the hole transport layer HTL may also include carbazole derivatives such as N-phenylcarbazole and polyvinylcarbazole, fluorene derivatives, triphenylamine derivatives such as N,N'-bis(3-methylphenyl)-N,N'-diphenyl-[1,1-biphenyl]-4,4'-diamine (TPD) and / or 4,4',4"-tri(N-carbazolyl)triphenylamine (TCTA), N,N'-di(naphthalene-1-yl)-N,N'-diphenyl-benzidine (NPD), 4,4'-cyclohexylbis[N,N-bis(4-methylphenyl)aniline] (TAPC), 4,4'-bis[N,N'-(3-tolyl)amino]-3,3'-dimethylbiphenyl (HMTPD) and / or 1,3-bis(N-carbazolyl)benzene (mCP), etc.

[0092] The hole transport region HTR may have a thickness of about 5 nm to about 1500 nm, and, for example, about 10 nm to about 500 nm. The hole injection layer HIL may have a thickness of, for example, about 3 nm to about 100 nm, and the hole transport layer HTL may have a thickness of about 3 nm to about 100 nm. For example, the electron blocking layer may have a thickness of about 1 nm to about 100 nm. When the thickness of each of the hole transport region HTR, the hole injection layer HIL, the hole transport layer HTL, and the electron blocking layer is within the above range, satisfactory or suitable hole transport characteristics may be obtained without increasing the driving voltage.

[0093] An emission layer EML may be provided on the hole transport region HTR. The emission layer EML may include a plurality of quantum dots QD.

[0094] The quantum dots QD contained in the emission layer EML can be stacked to form a layer. As an example, Figure 4 The quantum dots QD whose respective cross-sections are (substantially) circular are shown to be arranged so as to form two layers, but the present disclosure is not limited thereto. For example, the arrangement of the quantum dots QD may vary depending on the thickness of the emission layer EML, the shape of the quantum dots QD contained in the emission layer EML, and / or the average diameter of the quantum dots QD. For example, in the emission layer EML, the quantum dots QD may be arranged adjacent to each other and thus may form a layer, or may form a multilayer structure such as a two-layer structure or a three-layer structure. Reference will be made to Figure 5 and Figure 6 Quantum dots QD according to one or more embodiments are described in more detail.

[0095] In one or more embodiments, in the light emitting element ED according to one or more embodiments, the emission layer EML may include a host and a dopant. In one or more embodiments, the emission layer EML may include quantum dots QD as a dopant material. In one or more embodiments, the emission layer EML may further include a host material.

[0096] In the light emitting element ED according to one or more embodiments, the emission layer EML may be used to emit fluorescent light. For example, quantum dots QD may be used as a fluorescent dopant material.

[0097] In the light emitting element ED according to one or more embodiments, an electron transport region ETR may be provided on the emission layer EML. The electron transport region ETR may include at least one selected from a hole blocking layer, an electron transport layer ETL, and an electron injection layer EIL, but the present disclosure is not limited thereto.

[0098] The electron transport region ETR may have a single-layer structure formed of a single material, a single-layer structure formed of a plurality of different materials, or a multi-layer structure having a plurality of layers formed of a plurality of different materials.

[0099] For example, the electron transport region ETR may have a single-layer structure of an electron injection layer EIL or an electron transport layer ETL, or may have a single-layer structure formed by an electron injection material and an electron transport material. In one or more embodiments, the electron transport region ETR may have a single-layer structure formed by a plurality of different materials, or may have a multilayer structure of an electron transport layer ETL / electron injection layer EIL or a hole blocking layer / electron transport layer ETL / electron injection layer EIL in which a plurality of layers are sequentially stacked from the emission layer EML. However, the present disclosure is not limited thereto. The electron transport region ETR may have a thickness of, for example, about 20 nm to about 150 nm.

[0100] The electron transport region ETR may be formed using one or more suitable methods, such as a vacuum deposition method, a spin coating method, a casting method, a Langmuir-Blodgett method, an inkjet printing method, a laser printing method, and / or a laser induced thermal imaging (LITI) method.

[0101] When the electron transport region ETR includes an electron transport layer ETL, the electron transport region ETR may include an anthracene-based compound. However, the present disclosure is not limited thereto, and the electron transport region may include, for example, tris(8-hydroxyquinoline)aluminum (Alq 3 ), 1,3,5-tris[(3-pyridyl)-phenyl-3-yl]benzene, 2,4,6-tris(3'-(pyridin-3-yl)biphenyl-3-yl)-1,3,5-triazine, bis[2-(diphenylphosphine)phenyl]ether oxide (DPEPO), 2-(4-(N-phenylbenzimidazol-1-ylphenyl)-9,10-dinaphthylanthracene, 1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)phenyl (TPBi), 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP), 4,7-diphenyl Phenyl-1,10-phenanthroline (Bphen), 3-(4-biphenyl)-4-phenyl-5-tert-butylphenyl-1,2,4-triazole (TAZ), 4-(naphthalene-1-yl)-3,5-diphenyl-4H-1,2,4-triazole (NTAZ), 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole (tBu-PBD), bis(2-methyl-8-quinolinol-N1,O8)-(1,1'-biphenyl-4-quinolinol)aluminum (BAlq), bis(benzoquinolinol-10-ol)beryllium (Bebq 2), 9,10-di(naphthalene-2-yl)anthracene (ADN) and / or (e.g., any suitable) mixture thereof. The electron transport layer ETL may have a thickness of about 10 nm to about 100 nm, and for example, about 15 nm to about 50 nm. When the thickness of the electron transport layer ETL is within the above range, satisfactory or suitable electron transport performance may be obtained without substantially increasing the driving voltage.

[0102] When the electron transport region ETR includes an electron injection layer EIL, halogenated metals such as LiF, NaCl, CsF, RbCl and RbI, lanthanide metals such as Yb, metal oxides such as LiO, BaO and / or LiQ (lithium quinoline) can be used in the electron transport region ETR, but the present disclosure is not limited thereto. The electron injection layer EIL can also be formed by a mixed material of an electron transport material and an organic metal salt (e.g., a conductor) having conductivity. For example, the organic metal salt may include a metal acetate, a metal benzoate, a metal acetoacetate, a metal acetylacetonate and / or a metal stearate. The electron injection layer EIL may have a thickness of about 0.1 nm to about 10 nm, and about 0.3 nm to about 9 nm. When the thickness of the electron injection layer EIL is within the above range, satisfactory or suitable electron injection characteristics can be obtained without substantially increasing the driving voltage.

[0103] As described above, the electron transport region ETR may include a hole blocking layer. The hole blocking layer may include, for example, at least one selected from 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (BCP) and 4,7-diphenyl-1,10-phenanthroline (Bphen), but the present disclosure is not limited thereto.

[0104] The second electrode EL2 may be provided on the electron transport region ETR. The second electrode EL2 may be a common electrode or a negative electrode (or cathode). The second electrode EL2 may be a transmissive electrode, a semi-transmissive semi-reflective electrode or a reflective electrode. When the second electrode EL2 is a transmissive electrode, the second electrode EL2 may be formed of a transparent metal oxide, for example, indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO) and / or indium tin zinc oxide (ITZO), etc.

[0105] When the second electrode EL2 is a semi-transmissive and semi-reflective electrode or a reflective electrode, the second electrode EL2 may include Ag, Mg, Cu, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF, Mo, Ti, Yb or (e.g., any suitable) compound containing the same element (e.g., AgYb, AgMg and MgAg compounds according to the content) and / or their (e.g., any suitable) mixture (e.g., a mixture of Ag and Mg), or a material having a multilayer structure such as LiF / Ca or LiF / Al. In one or more embodiments, the second electrode EL2 may have a multilayer structure including a reflective film or a semi-transmissive and semi-reflective film each formed of the materials described above and a transparent conductive film formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO) and / or indium tin zinc oxide (ITZO), etc.

[0106] In one or more embodiments, the second electrode EL2 may be connected to the auxiliary electrode. When the second electrode EL2 is connected to the auxiliary electrode, the resistance of the second electrode EL2 may be reduced.

[0107] Figure 5 is a view schematically illustrating the structure of a quantum dot according to one or more embodiments of the present disclosure. Figure 6 is a view schematically illustrating the structure of a quantum dot according to one or more embodiments of the present disclosure.

[0108] Reference Figure 5 , the quantum dot QD may include a core CO and a first shell SH1 covering the core CO (eg, around the core CO or surrounding the core CO). Figure 6 In the embodiment, the quantum dot QD further includes a second shell SH2 covering the first shell SH1 (eg, around the first shell SH1 or surrounding the first shell SH1), which is Figure 5 The quantum dots QD in are different.

[0109] The core CO may include a I-III-VI semiconductor compound. The core CO may be a quaternary CuInGaS compound in the I-III-VI group. The core CO may include copper (Cu), indium (In), gallium (Ga) and sulfur (S). The core CO may be formed by copper, indium, gallium and sulfur. The quantum dot QD according to one or more embodiments includes a core CO containing a I-III-VI semiconductor compound, and therefore may have a high blue light absorptivity. In one or more embodiments, the quantum dot QD may be a non-Cd-based quantum dot. For example, the core CO of the quantum dot QD may not contain cadmium (Cd).

[0110] Relative to the total mass of 100wt% of the quantum dot QD, the quantum dot QD may include about 5wt% to about 20wt% of copper, about 5wt% to about 50wt% of gallium, about 5wt% to about 50wt% of indium, and about 30wt% to about 50wt% of sulfur. In the core CO, the mass ratio of gallium may be greater than the mass ratio of indium. For example, in the quantum dot QD, about 6.2wt% of copper, about 10.8wt% of gallium, about 7.7wt% of indium, and about 44.9wt% of sulfur may be included. The content (e.g., amount) of each element (e.g., copper, indium, gallium, and sulfur) contained in the core CO is adjusted within the above range, and thus the quantum dot QD according to one or more embodiments may have improved color reproducibility and light absorption characteristics. The content (e.g., amount) of each element (e.g., copper, indium, gallium, and sulfur) contained in the core CO varies within the above range, and thus the quantum dot QD according to one or more embodiments may be adjusted to emit light having a desired or suitable emission wavelength. For example, if the content (e.g., amount) of each element included in the core CO is within the above range (e.g., when the content (e.g., amount) of each element included in the core CO is within the above range), the quantum dot QD may emit light having an emission wavelength of about 560 nm to about 600 nm. Therefore, the quantum dot QD may emit green light having high color purity.

[0111] In one or more embodiments, the core CO may have a diameter of about 3 nm to about 6 nm. For example, the core CO may have a diameter of about 3.9 nm. If the core CO has a large diameter, the light absorption characteristics may be excellent or suitable, contributing to high quantum efficiency. The average diameter of the core CO is selected in a variety of ways within the above range, and thus the emission wavelength of the quantum dot QD and / or the semiconductor properties of the quantum dot QD, etc. may vary.

[0112] The core CO containing copper, indium, gallium and sulfur may have an absorption wavelength of about 350nm to about 530nm. Therefore, the core CO may absorb blue light in the above wavelength range and may emit green light or red light. The emission wavelength of light emitted from the quantum dot QD may be adjusted by adjusting the size of the core CO, the thickness of the first shell SH1 and / or the thickness of the second shell SH2, etc. The first shell SH1 and the second shell SH2 may each independently have a thickness of about 0.5nm to about 3nm. The thickness of the second shell SH2 may be greater than the thickness of the first shell SH1. The thickness of the second shell SH2 may be substantially the same as twice the thickness of the first shell SH1. For example, the first shell SH1 may have a thickness of about 1nm, and the second shell may have a thickness of about 2nm.

[0113] The first shell SH1 may include a II-VI group semiconductor compound. The first shell SH1 may include ZnS. The first shell SH1 may be formed of ZnS.

[0114] The second shell SH2 may completely cover the first shell SH1 (e.g., may be around the first shell SH1 or may surround the first shell SH1). Therefore, the surface of the quantum dot QD may be defined by the outer surface of the second shell SH2. The first shell SH1 may be covered by the second shell SH2 without being exposed in the quantum dot QD. The second shell SH2 may include at least one selected from ZnSe, ZnS, ZnTe, ZnO, ZnMg, ZnMgSe, ZnMgS, ZnMgAl, GaSe, GaTe, GaP, GaAs, GaSb, InAs, InSb, AlP, AlAs, AlSb, MnS, MnSe, MgS and MgSe. For example, the second shell SH2 may include ZnS. The concentration of ZnS contained in the first shell SH1 may be different from the concentration of ZnS contained in the second shell SH2. The concentration of ZnS may gradually change from the portion of the first shell SH1 adjacent to the core CO to the portion of the second shell SH2 adjacent to the outside. For example, the concentration of ZnS may gradually increase from the portion of the first shell SH1 adjacent to the core CO to the portion of the second shell SH2 adjacent to the outside. The mass of Zn contained in the quantum dot QD may be about 10wt% to about 50wt% relative to the total mass (100wt%) of the quantum dot QD. The quantum dot QD according to one or more embodiments may include a second shell SH2 covering the first shell SH1, and thus may exhibit high optical stability and chemical stability. The second shell SH2 may have a single-layer structure or a multi-layer structure. For example, the second shell SH2 may have a single-layer structure formed by a single material, a single-layer structure formed by a plurality of different materials, or a multi-layer structure having multiple layers formed by a plurality of materials. When the second shell SH2 has a multi-layer structure, the composition of each layer may be different. In this case, the composition of each layer may be changed discontinuously in the second shell SH2, or may be changed continuously in the second shell SH2 (for example, a gradient of the composition may be included).

[0115] The quantum dot QD according to one or more embodiments includes the first shell SH1 and the second shell SH2 and thus may have an excellent or suitable passivation effect at (on) the core CO. Therefore, the quantum dot QD according to one or more embodiments may exhibit high quantum yield characteristics.

[0116] The shape of the quantum dot QD is not particularly limited as long as it is a shape commonly used in the art, but in one or more embodiments, quantum dots in the shape of spherical nanoparticles, pyramidal nanoparticles, multi-arm nanoparticles or cubic nanoparticles, nanotubes, nanowires, nanofibers, and / or nanosheets, etc., may be used. In one or more embodiments, the quantum dot QD may be (e.g., may each be) substantially or approximately spherical.

[0117] The quantum dot QD may emit green light. The quantum dot QD may have an emission center wavelength of about 560nm to about 600nm. For example, the quantum dot QD may emit light having a maximum emission wavelength of about 560nm to about 600nm. However, the present disclosure is not limited thereto, and the quantum dot QD may emit red light. For example, the quantum dot QD may emit light having an emission center wavelength of about 630nm to about 680nm.

[0118] In one or more embodiments, the core CO may have a half-maximum full width (FWHM) of an emission wavelength spectrum of about 60nm to about 65nm. For example, the core CO may have a FWHM of an emission wavelength spectrum of about 64nm. The quantum dot QD according to one or more embodiments may have a half-maximum full width (FWHM) of an emission wavelength spectrum of about 65nm to about 70nm. For example, the quantum dot QD may have a half-maximum full width (FWHM) of an emission wavelength spectrum of about 75nm. Since the first shell SH1 is around the core CO (e.g., surrounding the core CO) and the second shell SH2 is around the first shell SH1 (e.g., surrounding the first shell SH1), the half-maximum full width (FWHM) of the core CO is less than the half-maximum full width (FWHM) of the quantum dot QD. When the first shell SH1 is around the core CO (e.g., surrounding the core CO) and the second shell SH2 is around the first shell SH1 (e.g., surrounding the first shell SH1), the half-maximum full width (FWHM) can be increased, and the optical stability and chemical stability of the quantum dot QD can be (significantly) increased. In one or more embodiments, light emitted by quantum dots QD may be emitted in all directions and thus the optical viewing angle may be improved.

[0119] In one or more embodiments, the quantum dot QD may also include a ligand chemically bonded to its surface. The ligand is chemically bonded to the surface of the quantum dot QD, thereby passivating the quantum dot QD. For example, the quantum dot QD may also include a ligand chemically bonded to the second shell SH2. In one or more embodiments, the ligand may include an organic ligand or a metal halide.

[0120] In one or more embodiments, the quantum dot QD may have a quantum yield maintenance rate represented by about 78% of Formula 1. Since the quantum yield maintenance rate of the quantum dot QD is about 78% or more, the quantum dot QD may exhibit excellent or suitable chemical stability, and thus may suppress or reduce changes caused by a purification process or an external environment.

[0121] Formula 1

[0122] Quantum yield maintenance rate = X 1 / X 0 ,

[0123] In the above formula 1, X 1 is the quantum yield of the quantum dots measured after 2 purifications using ethanol, and X 0 is the quantum yield of the quantum dots measured before purification.

[0124] Figure 7 is an enlarged plan view showing a portion of a display device DD according to one or more embodiments of the present disclosure. Figure 8 is a cross-sectional view of a display device DD according to one or more embodiments of the present disclosure. Figure 8 Shown along Figure 7 The part intercepted by line II-II' in. Fig. 9 is a cross-sectional view of a display device DD-1 according to one or more embodiments of the present disclosure. Fig. 9 A portion of a display area DA of a display panel DP according to one or more embodiments of the present disclosure is shown. Fig. 9 Shown along Figure 7 The part intercepted by line II-II' in.

[0125] Reference Figures 7 to 9 , the display device DD may include a non-emission region NPXA and emission regions PXA-B, PXA-G, and PXA-R. The emission regions PXA-B, PXA-G, and PXA-R may be regions that emit light generated in the light emitting elements ED-1, ED-2, and ED-3, respectively. The emission regions PXA-B, PXA-G, and PXA-R may be spaced and / or separated (e.g., spaced apart or separated) on a plane.

[0126] The emission regions PXA-B, PXA-G, and PXA-R may be divided into a plurality of groups according to the colors of light generated in the light emitting elements ED-1, ED-2, and ED-3. Figures 7 to 9In the display devices DD and DD-1 according to one or more embodiments shown in , three emission regions PXA-B, PXA-G, and PXA-R are shown as examples to emit blue light, green light, and red light, respectively. For example, the display devices DD and DD-1 according to one or more embodiments may include a blue emission region PXA-B, a green emission region PXA-G, and a red emission region PXA-R that are distinguished from each other.

[0127] Reference Figure 7 , the blue emission regions PXA-B and the red emission regions PXA-R may be arranged in turns (e.g., alternately) along the first direction DR1 to form a first group PXG1. The green emission regions PXA-G may be arranged in the first direction DR1 to form a second group PXG2. The first group PXG1 may be arranged away from the second group PXG2 in the second direction DR2. The first group PXG1 and the second group PXG2 may each provide a plurality. The first group PXG1 and the second group PXG2 may be arranged in turns (e.g., alternately) along the second direction DR2. One green emission region PXA-G may be arranged away from one blue emission region PXA-B or one red emission region PXA-R in the fourth direction DR4. The fourth direction DR4 may be a direction between the first direction DR1 and the second direction DR2. Figure 7 The arrangement structure of the emission regions PXA-B, PXA-G and PXA-R shown in FIG. structure( is a registered trademark of Samsung Display Co., Ltd. of South Korea).

[0128] However, the present disclosure is not limited thereto, and the emission regions PXA-B, PXA-G, and PXA-R may have a polygonal shape or a circular shape, and the arrangement structure of the light emitting regions is also not limited. For example, the emission regions PXA-B, PXA-G, and PXA-R may have a stripe structure along the first direction DR1, in which the blue emission regions PXA-B, the green emission regions PXA-G, and the red emission regions PXA-R are sequentially arranged in turn (e.g., alternately), or may have a diamond pixel arrangement.

[0129] Reference Figure 8, multiple light-emitting elements ED-1, ED-2, and ED-3 may emit light in different wavelength ranges. For example, in one or more embodiments, the display device DD may include a first light-emitting element ED-1 that emits blue light, a second light-emitting element ED-2 that emits green light, and a third light-emitting element ED-3 that emits red light. However, the present disclosure is not limited thereto, and the first light-emitting element ED-1, the second light-emitting element ED-2, and the third light-emitting element ED-3 may emit light in substantially the same wavelength region (or wavelength range), or at least one of the first light-emitting element ED-1, the second light-emitting element ED-2, and the third light-emitting element ED-3 may emit light in a wavelength region different from that of the above-described embodiments.

[0130] For example, the blue emission region PXA-B, the green emission region PXA-G, and the red emission region PXA-R of the display device DD may correspond to the first light emitting element ED-1, the second light emitting element ED-2, and the third light emitting element ED-3, respectively.

[0131] According to one or more embodiments, the display device DD includes a plurality of light emitting elements ED-1, ED-2 and ED-3, and according to one or more embodiments, at least one selected from the light emitting elements ED-1, ED-2 and ED-3 may include corresponding emission layers among the emission layers EL-B, EL-G and EL-R containing corresponding quantum dots among the quantum dots QD-C1, QD-C2 and QD-C3.

[0132] In one or more embodiments, the display device DD may include: a display panel DP including a plurality of light emitting elements ED-1, ED-2 and ED-3; and a light control layer PP arranged on the display panel DP. In one or more embodiments, in the display device DD according to one or more embodiments, the light control layer PP may not be provided.

[0133] The display panel DP may include a base substrate BS, a circuit layer DP-CL provided on the base substrate BS, and a display element layer DP-EL, and the display element layer DP-EL may include a pixel defining film PDL, light emitting elements ED-1, ED-2, ED-3 arranged between portions of the pixel defining film PDL, and an encapsulation layer TFE arranged on the light emitting elements ED-1, ED-2, ED-3.

[0134] The first emission layer EL-B of the first light emitting element ED-1 may include a first quantum dot QD-C1. The first quantum dot QD-C1 may emit blue light as the first light.

[0135] The second emission layer EL-G of the second light-emitting element ED-2 and the third emission layer EL-R of the third light-emitting element ED-3 may include a second quantum dot QD-C2 and a third quantum dot QD-C3, respectively. The second quantum dot QD-C2 and the third quantum dot QD-C3 may emit green light as the second light and red light as the third light, respectively.

[0136] At least one selected from the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 may be a quantum dot according to one or more of the above-described embodiments. In one or more embodiments, the second quantum dot QD-C2 may be a quantum dot according to one or more of the above-described embodiments. However, the present disclosure is not limited thereto, and each of the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 may be a quantum dot according to one or more of the above-described embodiments.

[0137] In one or more embodiments, the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 contained in the light-emitting elements ED-1, ED-2, and ED-3 may be formed of different core materials. In one or more embodiments, the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 may be formed of the same core material, or two quantum dots selected from the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 may be formed of the same core material, and the remaining quantum dots may be formed of different core materials.

[0138] In one or more embodiments, the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 may have different diameters. For example, the first quantum dot QD-C1 used in the first light-emitting element ED-1 emitting light in a relatively short wavelength region may have a relatively smaller average diameter than the second quantum dot QD-C2 used in the second light-emitting element ED-2 emitting light in a relatively long wavelength region and the third quantum dot QD-C3 used in the third light-emitting element ED-3 emitting light in a relatively long wavelength region.

[0139] In one or more embodiments, as used herein, the average diameter corresponds to the arithmetic mean of the diameters of a plurality of quantum dot particles. In one or more embodiments, the diameter of a quantum particle can be the average of the widths (e.g., diameters or lengths of major axes) of the quantum dot particles in a cross section.

[0140] The relationship between the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 and the average diameter is not limited to the above description. For example, Figure 8The first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 included in the light emitting elements ED-1, ED-2, and ED-3 are shown to have sizes similar to each other, but the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 may have different sizes. In one or more embodiments, two quantum dots selected from the first quantum dot QD-C1, the second quantum dot QD-C2, and the third quantum dot QD-C3 may have the same diameter, and the remaining quantum dots may have different sizes (e.g., different diameters).

[0141] In the display device DD according to one or more embodiments, as shown in FIG. Figure 7 and Figure 8 As shown in , the area of ​​each of the emission regions PXA-B, PXA-G, and PXA-R may be different. In this case, the area may refer to an area when viewed on a plane defined by the first direction DR1 and the second direction DR2 (eg, in a plan view).

[0142] Depending on the color of light emitted from the emission layers EL-B, EL-G, and EL-R of the light emitting elements ED-1, ED-2, and ED-3, respectively, the emission regions PXA-B, PXA-G, and PXA-R may have different areas. Figure 7 and Figure 8 In the display device DD according to one or more embodiments, the blue emission region PXA-B corresponding to the first light emitting element ED-1 emitting blue light may have the largest area, and the green emission region PXA-G corresponding to the second light emitting element ED-2 emitting green light may have the smallest area. However, the present disclosure is not limited thereto, and the emission regions PXA-B, PXA-G, and PXA-R may emit light of other colors in addition to blue light, green light, and red light, and the emission regions PXA-B, PXA-G, and PXA-R may have the same area, or may have the same area as described above. Figure 7 As shown in , the emission regions PXA-B, PXA-G, and PXA-R may be provided at different area ratios.

[0143] Each of the emission regions PXA-B, PXA-G, and PXA-R may be a region separated by a pixel defining film PDL. The non-emission region NPXA may include a region between adjacent emission regions PXA-B, PXA-G, and PXA-R, and may include (have) a region corresponding to a region of the pixel defining film PDL. In one or more embodiments, as used herein, each of the emission regions PXA-B, PXA-G, and PXA-R may correspond to a pixel. The pixel defining film PDL may separate the light emitting elements ED-1, ED-2, and ED-3. The emission layers EL-B, EL-G, and EL-R of the light emitting elements ED-1, ED-2, and ED-3 may be arranged in an opening portion OH defined by the pixel defining film PDL, thereby being separated from each other.

[0144] The pixel defining film PDL may be formed of a polymer resin. For example, the pixel defining film PDL may be formed to include a polyacrylate-based resin and / or a polyimide-based resin. In one or more embodiments, the pixel defining film PDL may be formed to include an inorganic material in addition to the polymer resin. At the same time, the pixel defining film PDL may be formed to include a light absorbing material, or may be formed to include a black pigment and / or a black dye. A pixel defining film PDL formed to include a black pigment and / or a black dye may realize a black pixel defining film. During the formation of the pixel defining film PDL, carbon black or the like may be used as a black pigment and / or a black dye, but the present disclosure is not limited thereto.

[0145] In one or more embodiments, the pixel definition layer PDL may be formed of an inorganic material. For example, the pixel definition layer PDL may be formed to include silicon nitride (SiN x ), silicon oxide (SiO x ) and / or silicon oxynitride (SiO x N y ) etc. The pixel definition film PDL may define the emission regions PXA-B, PXA-G, and PXA-R. The emission regions PXA-B, PXA-G, and PXA-R and the non-emission region NPXA may be defined by the pixel definition film PDL.

[0146] Each of the light emitting elements ED-1, ED-2 and ED-3 may include a first electrode EL1, a hole transport region HTR, a corresponding one of the emission layers EL-B, EL-G, EL-R, an electron transport region ETR, and a second electrode EL2. According to one or more embodiments, in the light emitting elements ED-1, ED-2 and ED-3 included in the display device DD, except that the quantum dots QD-C1, QD-C2 and QD-C3 included in the emission layers EL-B, EL-G and EL-R are different from each other, Figure 4The same description described in the above may apply to the first electrode EL1, the hole transport region HTR, the electron transport region ETR, and the second electrode EL2. In one or more embodiments, each of the light emitting elements ED-1, ED-2, and ED-3 may further include a cover layer between the second electrode EL2 and the encapsulation layer TFE.

[0147] The encapsulation layer TFE may cover the light emitting elements ED-1, ED-2, and ED-3. One or more layers may be stacked in the encapsulation layer TFE. The encapsulation layer TFE may be a thin encapsulation layer. The encapsulation layer TFE protects the light emitting elements ED-1, ED-2, and ED-3. The encapsulation layer TFE may cover the top surface of the second electrode EL2 arranged in the opening portion OH and fill the opening portion OH.

[0148] In one or more embodiments, Figure 8 In the embodiment of the present invention, the hole transport region HTR and the electron transport region ETR are shown to cover the pixel definition film PDL and be provided as a common layer, but the present disclosure is not limited thereto. In one or more embodiments, the hole transport region HTR and the electron transport region ETR may be arranged in the opening portion OH defined in the pixel definition film PDL.

[0149] For example, if a hole transport region HTR and / or an electron transport region ETR, etc. are provided in addition to the emission layers EL-B, EL-G, and EL-R using an inkjet printing method (for example, when a hole transport region HTR and / or an electron transport region ETR, etc. are provided in addition to the emission layers EL-B, EL-G, and EL-R using an inkjet printing method), the hole transport region HTR, the emission layers EL-B, EL-G, and EL-R, and / or the electron transport region ETR, etc. may be provided corresponding to the opening portion OH defined between the pixel defining films PDL. However, the present disclosure is not limited thereto, and regardless of the method for providing each functional layer, such as Figure 8 As shown in and etc., the hole transport region HTR and the electron transport region ETR may be provided as one common layer while covering the pixel defining layer PDL without being patterned.

[0150] In one or more embodiments, in the display device DD, for example, Figure 8 As shown in the figure, all emission layers EL-B, EL-G, and EL-R of the first light-emitting element ED-1, the second light-emitting element ED-2, and the third light-emitting element ED-3 are shown to have similar thicknesses, but the present disclosure is not limited thereto. For example, in one or more embodiments, the emission layers EL-B, EL-G, and EL-R of the first light-emitting element ED-1, the second light-emitting element ED-2, and the third light-emitting element ED-3 may have different thicknesses.

[0151] Reference Figure 8The display device DD according to one or more embodiments may further include a light control layer PP. The light control layer PP may block or reduce external light provided from outside the display device DD to the display panel DP. The light control layer PP may block or reduce some of the external light. The light control layer PP may have an anti-reflection function to minimize or reduce reflection due to external light.

[0152] In such Figure 8 In one or more embodiments shown in , the light control layer PP may include a color filter layer CFL. For example, the display device DD according to one or more embodiments may further include a color filter layer CFL arranged on the light emitting elements ED-1, ED-2, and ED-3 of the display panel DP.

[0153] In the display device DD according to one or more embodiments, the light control layer PP may include a base layer BL and a color filter layer CFL.

[0154] The base layer BL may be a member that provides a base surface on which the color filter layer CFL, etc. is arranged. The base layer BL may be a glass substrate, a metal substrate, and / or a plastic substrate, etc. However, the present disclosure is not limited thereto, and the base layer BL may be an inorganic layer, an organic layer, or a composite material layer.

[0155] The color filter layer CFL may include a blocking member BM and a color filter portion CF. The color filter portion CF may include a plurality of filters CF-B, CF-G, and CF-R. For example, the color filter layer CFL may include a first filter CF-B that transmits a first light, a second filter CF-G that transmits a second light, and a third filter CF-R that transmits a third light. For example, the first filter CF-B may be a blue filter, the second filter CF-G may be a green filter, and the third filter CF-R may be a red filter.

[0156] Each of the filters CF-B, CF-G, and CF-R may include a polymer photosensitive resin, a pigment, and / or a dye. The first filter CF-B may include a blue pigment and / or a dye, the second filter CF-G may include a green pigment and / or a dye, and the third filter CF-R may include a red pigment and / or a dye.

[0157] However, the present disclosure is not limited thereto, and the first filter CF-B may not include a pigment or dye. The first filter CF-B may include a polymer photosensitive resin and may not include a pigment or dye. The first filter CF-B may be transparent. The first filter CF-B may be formed of a transparent photosensitive resin.

[0158] The blocking member BM may be a black matrix. The blocking member BM may be formed to include an organic blocking material or an inorganic blocking material including a black pigment and / or a black dye. The blocking member BM may prevent or reduce light leakage and separate (define) the boundaries between adjacent filters CF-B, CF-G, and CF-R. In one or more embodiments, the blocking member BM may be formed by a blue filter.

[0159] The first filter CF-B, the second filter CF-G, and the third filter CF-R may be arranged corresponding to the blue emission area PXA-B, the green emission area PXA-G, and the red emission area PXA-R, respectively.

[0160] The color filter layer CFL may further include a buffer layer BFL. For example, the buffer layer BFL may be a protective layer for protecting the color filters CF-B, CF-G, and CF-R. The buffer layer BFL may be an inorganic layer including at least one inorganic material among silicon nitride, silicon oxide, and silicon oxynitride. The buffer layer BFL may be formed of a single layer or a plurality of layers.

[0161] In the color filter layer CFL according to one or more embodiments, the blocking member BM may not be provided, and each of the first filter CF-B, the second filter CF-G, and the third filter CF-R may be arranged to overlap with each other in the non-emission area NPXA. The first filter CF-B, the second filter CF-G, and the third filter CF-R arranged to overlap with each other in the non-emission area NPXA may perform the function of the omitted blocking member BM.

[0162] In one or more embodiments, the display device DD may include a polarizing layer instead of the color filter layer CFL as the light control layer PP. The polarizing layer may block or reduce external light provided on the display panel DP from the outside. The polarizing layer may block or reduce some of the external light.

[0163] In one or more embodiments, the polarization layer may reduce the reflected light reflected on the display panel DP due to external light. For example, in the case where light provided from the outside of the display device DD is incident on the display panel DP and re-emitted (e.g., reflected), the polarization layer may play a role in blocking or reducing the reflected light. The polarization layer may be a circular polarizer with an anti-reflection function, or the polarization layer may include a linear polarizer and a λ / 4 phase retarder. In one or more embodiments, the polarization layer may be arranged on the base layer BL so as to be exposed, or the polarization layer may be arranged below the base layer BL.

[0164] Reference Fig. 9According to one or more embodiments, the display device DD-1 may include a light conversion layer CCL disposed on the display panel DP-1. In one or more embodiments, the display device DD-1 may further include a color filter layer CFL. The color filter layer CFL may be disposed between the base layer BL and the light conversion layer CCL.

[0165] The display panel DP-1 may be a light-emitting type or a luminescent type display panel. For example, the display panel DP-1 may be an organic electroluminescent display panel or a quantum dot emission display panel.

[0166] The display panel DP-1 may include a base substrate BS, a circuit layer DP-CL and a display element layer DP-EL1 provided on the base substrate BS.

[0167] The display element layer DP-EL1 may include a light emitting element ED-a, and the light emitting element ED-a may include a first electrode EL1 and a second electrode EL2 facing (eg, opposite) each other and a plurality of layers OL disposed between the first electrode EL1 and the second electrode EL2. The plurality of layers OL may include a hole transport region HTR (see, for example, Figure 4 ), emission layer EML (see e.g. Figure 4 ) and the electron transport region ETR (see Figure 4 ). The encapsulation layer TFE may be disposed on the light emitting element ED-a.

[0168] In the light-emitting element ED-a, the Figure 4 and Figure 8 The same description described in applies to the first electrode EL1, the hole transport region HTR, the electron transport region ETR, and the second electrode EL2. However, in the light-emitting element ED-a included in the display panel DP-1 according to one or more embodiments, the emission layer may include a host and a dopant of an organic electroluminescent material, or may include quantum dots according to one or more of the above-mentioned embodiments. In the display panel DP-1 according to one or more embodiments, the light-emitting element ED-a may emit blue light.

[0169] The light conversion layer CCL may include a plurality of partition walls BK arranged away from each other and light control parts CCP-B, CCP-G and CCP-R between the partition walls BK. The partition walls BK may be formed by including a polymer resin and a liquid-proof additive. The partition walls BK may be formed by including a light-absorbing material, or may be formed by including a pigment and / or a dye. For example, the partition walls BK may include a black pigment and / or a black dye to realize a black partition wall. When forming a black partition wall, carbon black or the like may be used as a black pigment, but the present disclosure is not limited thereto.

[0170] The light conversion layer CCL may include a first light control part CCP-B that transmits a first light, a second light control part CCP-G that includes a fourth quantum dot QD-C2a that converts the first light into a second light, and a third light control part CCP-R that includes a fifth quantum dot QD-C3a that converts the first light into a third color light. The second light may be light in a longer wavelength region than the first light, and the third light may be light in a longer wavelength region than the first light and the second light. For example, the first light may be blue light, the second light may be green light, and the third light may be red light. The same description as the quantum dot in one or more of the above-mentioned embodiments may be applied to at least one selected from the quantum dots QD-C2a and QD-C3a included in the light control parts CCP-G and CCP-R. For example, the same description of the quantum dot in one or more of the above-mentioned embodiments may be applied to the fourth quantum dot QD-C2a that converts the first light into the second light.

[0171] The light conversion layer CCL may further include a cover layer CPL. The cover layer CPL may be arranged on the light control parts CCP-B, CCP-G and CCP-R and the partition wall BK. The cover layer CPL may be used to prevent or reduce moisture and / or oxygen from penetrating into the display device DD-1. The cover layer CPL may be arranged on the light control parts CCP-B, CCP-G and CCP-R and may block or substantially block the light control parts CCP-B, CCP-G and CCP-R from being exposed to moisture and / or oxygen. The cover layer CPL may include at least one inorganic layer.

[0172] The display device DD-1 according to one or more embodiments may include a color filter layer CFL disposed on the light conversion layer CCL, and Figure 8 The same description as in can be applied to the color filter layer CFL and the base layer BL.

[0173] Fig.10 is a flow chart showing a method for preparing quantum dots according to one or more embodiments of the present disclosure. Figure 4 )’s description.

[0174] Reference Fig.10 According to one or more embodiments, the method for preparing quantum dots includes: providing a first mixture (S100), the first mixture including a first precursor including gallium oleate, a second precursor including indium oleate, and a third precursor including sulfur atoms; forming a second mixture by adding a first solvent to the first mixture (S110); and forming a fourth mixture by adding a third mixture including copper to the second mixture, the fourth mixture including cores including copper atoms, indium atoms, gallium atoms, and sulfur atoms (S120).

[0175] In providing the first mixture ( S100 ), gallium oleate included in the first precursor may be synthesized through reaction scheme 1 , and indium oleate included in the second precursor may be synthesized through reaction scheme 2 .

[0176] Reaction Scheme 1

[0177]

[0178] Reaction Scheme 2

[0179]

[0180] Gallium oleate and indium oleate adjust the chemical reaction rate during the core synthesis process, thereby increasing the diameter of the core, and thereby making the core size relatively or substantially consistent with the core prepared using a gallium or indium precursor that is not substituted with oleic acid. When the core has a large size, the light absorption performance can be improved, and if the core size is substantially consistent (for example, when the core size is substantially consistent), the half-maximum full width is improved, and thus the color reproducibility can be excellent or suitable. The molar concentration of gallium oleate and indium oleate can each be about 0.5M.

[0181] The third precursor containing a sulfur atom can be synthesized through Reaction Scheme 3.

[0182] Reaction Scheme 3

[0183]

[0184] The molar concentration of the third precursor including sulfur atoms may be about 1M.

[0185] The first mixture may include a first precursor containing gallium oleate, a second precursor containing indium oleate, and a third precursor containing sulfur atoms within a certain amount range. In the first mixture, the molar ratio of gallium atoms, indium atoms, and sulfur atoms may be about 1:1:2. For example, in the first mixture, the molar concentration of gallium atoms may be about 0.5M, the molar concentration of indium atoms may be about 0.5M, and the molar concentration of sulfur atoms may be about 1M.

[0186] In the formation (S110) of the second mixture, the first solvent may include at least one selected from 1-octadecene and trioctylamine. The first solvent may play a role in dissolving the first precursor, the second precursor, and the third precursor. 1-octadecene may not directly participate in the chemical reaction, and may contribute to the concentration adjustment of the material in the second mixture and the viscosity of the second mixture. Trioctylamine may contribute to the concentration adjustment and reaction rate adjustment of the material in the second mixture.

[0187] The second mixture may include a first precursor containing gallium oleate, a second precursor containing indium oleate, and a third precursor containing sulfur atoms in a certain proportion. In the second mixture, the mole number of the first precursor may be greater than the mole number of the second precursor. For example, the mole number of gallium atoms may be greater than the mole number of indium atoms. The second mixture may include about 0.5 mmol to about 0.7 mmol of the first precursor, about 0.3 mmol to about 0.5 mmol of the second precursor, and about 1.2 mmol to about 2.0 mmol of the third precursor. For example, the second mixture may include a first precursor, a second precursor, and a third precursor in a molar ratio of about 6:4:16.

[0188] The formation of the fourth mixture (S120) may include forming a core. The formation of the core may include: in a nitrogen atmosphere, forming a fourth mixture by adding a third mixture containing copper to the second mixture; and reacting the fourth mixture at a first temperature for about 5 minutes to about 15 minutes. In the formation of the fourth mixture, the third mixture containing copper may include cupric acetate (cuprous acetate). When the fourth mixture is reacted at a first temperature for about 5 minutes to about 15 minutes, the first temperature may be about 250°C to about 350°C. For example, the fourth mixture may react at about 250°C for about 10 minutes. When the fourth mixture reacts at a first temperature for about 5 minutes to about 15 minutes, the first precursor, the second precursor, and the third precursor each contained in the second mixture and the copper contained in the third mixture may react to form a core. If the fourth mixture reacts at a first temperature, the plurality of cores formed have substantially uniform sizes, and thus color reproducibility may be improved. The core formed after the reaction may have a diameter (e.g., an average diameter) of about 3nm to about 6nm. For example, the core may have a diameter of about 3.9nm. When the core has a large diameter, the light absorption characteristics may be excellent or suitable, and the core may contribute to high quantum efficiency. By selecting different average diameters of the core within the above range, the quantum dot QD may be variously changed (see, e.g. Figure 4 )’s emission wavelength and / or the semiconductor properties of the quantum dots.

[0189] The method for preparing quantum dots according to one or more embodiments may further include forming a first shell covering the core (eg, around the core) by reacting the core, a fourth precursor containing zinc oleate, and a fifth precursor containing a sulfur atom.

[0190] In the formation of the first shell, the fifth precursor may include trioctylphosphine sulfide. The fourth precursor and the fifth precursor may each independently have a mole of about 0.4mmol to about 1.6mmol. When the fourth precursor and the fifth precursor each independently have a mole of about 0.4mmol to about 1.6mmol, the light absorption characteristics and quantum efficiency of the quantum dot can be improved. The molar ratio of the fourth precursor to the fifth precursor may be about 1:1. The mole of zinc oleate contained in the fourth precursor and the mole of trioctylphosphine sulfide contained in the fifth precursor may each be about 0.8mmol. In the quantum dot, the mass of the gallium atom may be about 5wt% (e.g., weight % or mass %) to about 50wt% relative to the total mass of the quantum dot of 100wt%. The mass ratio of gallium atoms to quantum dots may be greater than the mass ratio of indium atoms to quantum dots. Relative to the total mass of the quantum dot, the mass of the indium atoms may be about 5 wt% to about 50 wt%, the mass of the copper may be about 5 wt% to about 20 wt%, the mass of the sulfur atoms may be about 30 wt% to about 50 wt%, and the mass of the zinc atoms may be about 10 wt% to about 50 wt%. For example, the quantum dot (e.g., each quantum dot or an average value among the quantum dots) may include about 6.2 wt% copper, about 10.8 wt% gallium, about 7.7 wt% indium, about 44.9 wt% sulfur, and about 30.4 wt% zinc.

[0191] The forming of the first shell may be performed at the second temperature for about 15 minutes to about 25 minutes. The second temperature may be about 280° C. to about 350° C. For example, the forming of the first shell may be performed at about 280° C. for about 20 minutes.

[0192] In the method for preparing quantum dots according to one or more embodiments, the first solvent may include 1-octadecene and trioctylamine, and before forming the first shell, the method for preparing quantum dots according to one or more embodiments may further include degassing trioctylamine at about 120°C. After degassing trioctylamine at about 120°C, the first solvent may include 1-octadecene and may not include trioctylamine. Trioctylamine has the function of slowing down chemical reactions, and therefore, during the formation of the core, it may contribute to the basic consistency of the core diameter. However, during the formation process of the first shell, it is important to improve optical stability and chemical stability by quickly forming the first shell. Therefore, if trioctylamine is degassed (for example, when trioctylamine is degassed), the first shell may be quickly formed, thereby improving the optical stability and chemical stability of the core. The first shell may have a thickness of about 0.5nm to about 3nm. For example, the first shell may have a thickness of about 1nm. The thickness of the first shell is adjusted within a certain range, and therefore, the decline in light absorption performance and emission performance can be minimized or reduced, while the optical stability and chemical stability of the core can be improved.

[0193] According to one or more embodiments, the method for preparing quantum dots may further include, after the formation of the first shell, forming a second shell covering the first shell (e.g., around the first shell) by adding a first element precursor and a second element precursor to a first particle including a core and the first shell.

[0194] In the formation of the second shell, the first element precursor may include at least one selected from zinc atoms, gallium atoms, indium atoms, aluminum atoms, manganese atoms, and magnesium atoms. The second element precursor may include at least one selected from selenium atoms, sulfur atoms, tellurium atoms, oxygen atoms, phosphorus atoms, arsenic atoms, and antimony atoms. For example, the first element precursor may include zinc atoms, and the second element precursor may include sulfur atoms. The first element precursor may be the same as the fourth precursor. The second element precursor may be the same as the fifth precursor.

[0195] Hereinafter, the quantum dots according to one or more embodiments of the present disclosure will be further described with reference to examples and comparative examples. In addition, the examples shown below are only for illustration to assist in understanding the present disclosure, and the scope of the present disclosure is not limited thereto.

[0196] Example

[0197] Synthesis of Quantum Dots According to Example 1

[0198] Step 1: Synthesis of CuInGaS core

[0199] 0.3 mmol to 1 mmol of gallium oleate, 0.1 mmol to 0.5 mmol of indium oleate, and 0.1 mmol to 2 mmol of cuprous acetate are put into a flask together with 10 mmol to 50 mmol of oleylamine, 1 mmol to 20 mmol of 1-octadecene, and 1 mmol to 20 mmol of trioctylamine, and then the mixture is degassed at about 120° C. and stirred for about 30 minutes to form a reaction solution. Then, 1 mmol to 2 mmol of diphenylphosphine sulfide is injected into the reaction solution, and the product is reacted for about 10 minutes while being heated to about 250° C., thereby synthesizing a CuInGaS core.

[0200] Step 2: Synthesis of CuInGaS / ZnS

[0201] The solution containing the synthesized CuInGaS core is heated to about 120°C, and 20 to 50 mmol of trioctylamine is degassed. Then, the atmosphere is replaced with nitrogen, the CuInGaS core is diluted in toluene, and precipitated with ethanol for purification. 0.4 to 1.6 mmol of zinc oleate and 0.4 to 1.6 mmol of trioctylphosphine sulfide are injected into the toluene solution containing 1 to 2 mmol of the purified CuInGaS core, and reacted at about 280°C for about 20 minutes to form a ZnS shell.

[0202] Comparison Examples

[0203] Synthesis of Quantum Dots According to Comparative Example 1

[0204] Step 1: Synthesis of CuInGaS core

[0205] 0.2 mmol of CuI and 0.5 mmol of GaI 3 and 0.4mmol of InI 3 0.85 mmol of trioctylphosphine oxide (TOPO), 10 mmol to 50 mmol of oleylamine and 1 mmol to 20 mmol of trioctylamine were placed in a flask and mixed. Then, the mixture was degassed at about 120° C. and stirred for about 30 minutes to form a reaction solution. Thereafter, in a nitrogen atmosphere, 0.4 mmol to 1.6 mmol of diphenylphosphine sulfide was injected into the reaction solution, and the resulting solution was reacted under heating to about 220° C., thereby synthesizing a CuInGaS core.

[0206] Step 2: Synthesis of CuInGaS / ZnS

[0207] CuInGaS / ZnS was prepared in substantially the same manner as in step 2 of the synthesis of Example 1.

[0208] Synthesis of Quantum Dots According to Comparative Example 2

[0209] Step 1: Synthesis of InP core

[0210] 10 mmol of indium acetate, 10 mmol of zinc acetate, and 70 mmol of palmitic acid were mixed with 4.5 mmol of oleylamine and 0.5 mmol of sodium oleate as additives in 50 mL of 1-octadecene solvent to prepare a cationic precursor.

[0211] Tri(trimethylsilyl)phosphine and trioctylphosphine are mixed to prepare an anion precursor.

[0212] The manufactured two types or two precursors are mixed, and then the product is maintained at about 300° C. to prepare an InP core.

[0213] Step 2: Synthesis of InP / ZnS

[0214] 1 mmol to 2 mmol of InP cores dispersed in toluene are mixed with 10 mmol to 50 mmol of trioctylamine and 1 mmol to 10 mmol of zinc oleate, and then degassed at about 110° C. or higher. Then, in a nitrogen atmosphere, 0.4 mmol to 1.6 mmol of trioctylphosphine sulfide and 0.4 mmol to 1.6 mmol of zinc oleate are injected, and the product is reacted at about 320° C. or higher to synthesize InP / ZnS.

[0215] Fig.11 The absorbance and emission spectra of the quantum dots according to Example 1 are shown. Fig.12 Absorbance spectra of quantum dots according to Example 1 and Comparative Example 2 are shown. Fig.11 The vertical axis of the graph shown in represents the absorbance (au) and the luminous intensity (au), and the horizontal axis represents the emission wavelength band. Fig.12 The vertical axis of the graph shown in represents the absorbance (au), and the horizontal axis represents the emission wavelength band. Fig.12 1 and 2 are simulation data of the absorbance of quantum dots according to Example 1 and Comparative Example 2.

[0216] Reference Fig.11, it can be confirmed that the quantum dots according to Example 1 have an emission peak showing high emission intensity in the wavelength range of about 560nm to about 600nm. The first emission peak may be caused by band edge emission. It can be confirmed that the quantum dots formed by the method for preparing quantum dots according to one or more embodiments show high emission intensity in the wavelength range of about 560nm to about 600nm. Therefore, the method for preparing quantum dots according to one or more embodiments can provide quantum dots having excellent or suitable emission characteristics due to high emission intensity. In addition, as the wavelength becomes smaller in the blue light emitting wavelength region of about 380nm to about 450nm, high absorbance is exhibited. Refer to together Fig.11 and Fig.12 , as the quantum dots are emitted at shorter wavelengths in the blue light region, the absorbance of the quantum dots according to Example 1 continues to increase. However, compared with the quantum dots of Example 1, the quantum dots according to Comparative Example 2 exhibit a phenomenon in which the absorbance repeatedly rises and falls. This is because the InP in the quantum dots according to Comparative Example 2 has a Bohr radius of about 9nm, and because the quantum dots according to Comparative Example 2 should have a particle size of about 2nm to about 4nm in order to emit light in the visible light region, the quantum dots are subject to a strong quantum confinement effect. In contrast, because the quantum dots according to Example 1 have a Bohr radius of about 4.5nm, the quantum dots are subject to a weak quantum confinement effect compared to the quantum dots of Comparative Example 2, and therefore as the quantum dots emit light with a shorter wavelength in the blue light wavelength region, the absorbance continues to increase. Therefore, the light absorption performance is excellent or suitable.

[0217] The maximum emission wavelength, full width at half maximum and average diameter of the core according to Example 1 were compared with those of the core according to Comparative Example 1, and the values ​​are listed in Table 1. When the full width at half maximum is smaller, it means that the color reproducibility is improved.

[0218] Table 1

[0219] Maximum emission wavelength Full Width at Half Maximum Average diameter According to the core of Comparative Example 1 594nm 82nm 2.4nm According to the kernel of Example 1 583nm 64nm 3.9nm

[0220] Referring to Table 1, the maximum emission wavelengths of the cores according to Example 1 and Comparative Example 1 are about 583 nm and about 594 nm, respectively, falling within the green wavelength region. The core according to Example 1 has a diameter that is 1.625 times larger than the diameter of the core according to Comparative Example 1. Without being bound by any particular theory, it is believed that as the size (e.g., diameter) of the core of the quantum dot increases, the light absorption performance is improved. In addition, since the core according to an embodiment of the present disclosure has a substantially uniform size, the full width at half maximum of the core according to Example 1 is reduced compared to the core according to Comparative Example 1, and thus the color reproducibility is improved.

[0221] The weight absorption coefficients (mL / mg·cm) of the quantum dots according to Example 1 and Comparative Example 2 are listed in Table 2 to indicate the absorbance performance. The higher the weight absorption coefficient, the better the absorbance performance of the quantum dots.

[0222] Table 2

[0223] Weight absorption coefficient Comparative Example 2 250 (mL / mg·cm) Example 1 816 (mL / mg·cm)

[0224] Referring to Table 2 above, the quantum dots according to Example 1 have a weight absorption coefficient that is approximately 3.3 times greater than that of the quantum dots according to Comparative Example 2. Without being bound by any particular theory, it can be explained that because the Bohr radius of CuInGaS included in the core of the quantum dots according to Example 1 is smaller than the Bohr radius of InP included in the core of the quantum dots according to Comparative Example 2, the quantum confinement effect is smaller and thus the absorbance performance is improved.

[0225] According to one or more embodiments of the present disclosure, a method for preparing quantum dots can use a precursor containing gallium oleate and indium oleate to prepare quantum dots including a core containing a quaternary CuInGaS compound. In related or comparative methods for synthesizing quantum dots, because metal halides are used as precursors, the chemical reaction rate is excessively (or significantly) high, and thus the core of the quantum dot has a small and inconsistent size. In contrast, in a core prepared according to a method for preparing a quantum dot according to the present disclosure, a precursor containing gallium oleate and indium oleate is used, and thus the core can have a relatively large and substantially uniform diameter compared to existing quantum dots. When the core has a large diameter, the light absorption characteristics can be excellent or suitable, and the core can contribute to high quantum efficiency. When the size of the core is substantially uniform, the color reproducibility is excellent or suitable. By changing the average diameter of the core within the above range, the emission wavelength of the quantum dot and / or the semiconductor properties of the quantum dot can be changed in various ways.

[0226] A method for preparing quantum dots according to one or more embodiments includes providing a first precursor containing gallium oleate and a second precursor containing indium oleate, and thus can provide quantum dots having a large (e.g., larger or relatively large) and substantially consistent size compared to related or comparative quantum dots, thereby exhibiting improved color reproducibility and light absorption characteristics.

[0227] Quantum dots according to one or more embodiments have large and substantially consistent sizes compared to related or comparative quantum dots, and thus may exhibit improved color reproducibility and light absorption characteristics.

[0228] As used herein, the terms "substantially," "approximately," and similar terms are used as terms of approximation rather than terms of degree, and are intended to account for the inherent deviations in measured or calculated values ​​that one of ordinary skill in the art would recognize. As used herein, "substantially" includes the stated value, as well as methods of expressing within an acceptable range of deviation for a particular value as determined by one of ordinary skill in the art, taking into account the measurement in question and the errors associated with the measurement of a particular quantity (i.e., the limitations of the measurement system). For example, "substantially" can mean within one or more standard deviations, or within ±30%, ±20%, ±10%, or ±5% of the stated value.

[0229] In addition, any numerical range recorded herein is intended to include all sub-ranges with the same numerical precision contained in the recorded range. For example, the range of "1.0 to 10.0" is intended to include all sub-ranges between the minimum value of 1.0 (and including the minimum value of 1.0) and the maximum value of 10.0 (and including the maximum value of 10.0), that is, having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit recorded herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit recorded in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to modify this specification (including claims) to explicitly record any sub-range contained in the range explicitly recorded herein.

[0230] Furthermore, when describing embodiments of the present disclosure, the use of “may” refers to “one or more embodiments of the present disclosure.”

[0231] According to the light-emitting device, electronic device, or any other related device or component of the embodiment of the present disclosure described herein, any suitable hardware, firmware (e.g., application specific integrated circuit), software, or a combination of software, firmware, and hardware can be implemented. For example, the various components of the device can be formed in an integrated circuit (IC) chip or in a separate IC chip. In addition, the various components of the device can be implemented on a flexible printed circuit film, a tape carrier package (TCP), a printed circuit board (PCB), or formed on a substrate. In addition, the various components of the device can be processes or threads running on one or more processors in one or more computing devices, executing computer program instructions and interacting with other system components to perform various functions described herein. Computer program instructions are stored in a memory, which can be implemented in a computing device using a standard memory device (such as, for example, a random access memory (RAM)). Computer program instructions can also be stored in other non-temporary computer-readable media (such as, for example, a CD-ROM or a flash drive, etc.). In addition, it should be appreciated by those skilled in the art that, without departing from the scope of the embodiments of the present disclosure, the functions of various computing devices can be combined or integrated into a single computing device, or the functions of a specific computing device can be distributed across multiple other computing devices.

[0232] Although embodiments of the present disclosure have been described, it should be understood that the present disclosure should not be limited to these embodiments, but a person skilled in the art may make one or more appropriate changes and modifications within the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.

Claims

1. A method for preparing quantum dots, wherein: The method comprises: A first mixture is provided, the first mixture comprising: a first precursor comprising gallium oleate; a second precursor comprising indium oleate; and a third precursor comprising a sulfur atom; forming a second mixture by adding a first solvent to the first mixture; and A fourth mixture is formed by adding the third mixture including copper to the second mixture, the fourth mixture including cores including copper atoms, indium atoms, gallium atoms, and sulfur atoms.

2. The method according to claim 1, wherein: The core has a diameter of 3 nm to 6 nm.

3. The method according to claim 1, wherein: The first solvent includes at least one selected from 1-octadecene and trioctylamine.

4. The method according to claim 1, wherein: The method further comprises: reacting the fourth mixture at the first temperature for 5 minutes to 15 minutes, Wherein, the first temperature is 250°C to 350°C.

5. The method according to claim 1, wherein: In the second mixture, the molar number of gallium atoms is greater than the molar number of indium atoms.

6. The method according to claim 1, wherein: The method also includes forming a first shell around the core by reacting the core with a fourth precursor containing zinc oleate and a fifth precursor containing a sulfur atom.

7. A quantum dot, wherein The quantum dots include: nuclei including copper, indium, gallium, and sulfur atoms; and a first shell, surrounding the core and comprising zinc atoms and sulfur atoms, Wherein, the core has a diameter of 3 nm to 6 nm.

8. The quantum dot according to claim 7, wherein In the quantum dots: The mass of gallium atoms is 5 wt % to 50 wt % relative to 100 wt % of the total mass of the quantum dots; and A ratio of the mass of gallium atoms relative to the total mass of the quantum dots is greater than a ratio of the mass of indium atoms relative to the total mass of the quantum dots.

9. The quantum dot according to claim 7, wherein The quantum dots also include: A second shell surrounds the first shell, and the second shell includes at least one selected from ZnSe, ZnS, ZnTe, ZnO, ZnMg, ZnMgSe, ZnMgS, ZnMgAl, GaSe, GaTe, GaP, GaAs, GaSb, InAs, InSb, AlP, AlAs, AlSb, MnS, MnSe, MgS and MgSe.

10. The quantum dot according to claim 9, wherein The thickness of the second shell is greater than the thickness of the first shell.

Images