Quantum dot and display device including the same

Abstract

Provided are a quantum dot and a display device including the same, the quantum dot including: a core including copper, indium, gallium, silver, and sulfur; and a shell surrounding the core and including zinc sulfide. The display device includes: a base layer; a circuit layer on the base layer; and a display element layer on the circuit layer, the display element layer including: a first electrode; a second electrode; and a light emitting layer between the first electrode and the second electrode and including quantum dots.

Description

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0121371, filed on September 12, 2023, and Korean Patent Application No. 10-2024-0079600, filed on June 19, 2024, which are hereby incorporated by reference in their entirety. Technical Field

[0002] Embodiments of the present disclosure relate to a quantum dot and a display device. For example, embodiments of the present disclosure relate to a quantum dot including a core and a shell and a display device including the quantum dot. Background Art

[0003] Various display devices are being developed for use in multimedia devices such as televisions, mobile phones, tablet computers, navigation devices, and gaming devices. In the display devices, quantum dots are used to form light-emitting elements or to convert properties of source light. Summary of the invention

[0004] An embodiment of the present disclosure provides a quantum dot including a core and a shell including copper, indium, gallium, sulfur, and silver, and having high color purity and high photostability.

[0005] An embodiment of the present disclosure provides a display device including quantum dots and having high reliability.

[0006] An embodiment of the present disclosure provides a quantum dot including a core including copper, indium, gallium, silver, and sulfur and a shell surrounding the core and including zinc sulfide (ZnS).

[0007] The quantum dots can emit green light having a central wavelength equal to or greater than about 500 nm and equal to or less than about 550 nm, the quantum dots including the core and the shell have a diameter equal to or greater than about 2 nm and equal to or less than about 4 nm, and the ratio of the number of moles of silver to the sum of the number of moles of silver and copper can be equal to or greater than about 0.001 and equal to or less than about 0.200.

[0008] The quantum dots may emit red light having a central wavelength of about 580 nm or more and about 660 nm or less, the quantum dots including the core and the shell may have a diameter of about 5 nm or more and about 10 nm or less, and the ratio of the number of moles of silver to the sum of the number of moles of silver and copper may be about 0.001 or more and about 0.200 or less. The light emitted from the quantum dots has a full width at half maximum (FWHM) of about 25 nm or more and about 60 nm or less.

[0009] The quantum dot also includes at least one outer shell surrounding the shell.

[0010] At least one shell includes ZnSe, ZnS, ZnTe, ZnO, ZnMg, ZnMgSe, ZnMgS, ZnMgAl, GaSe, GaTe, GaP, GaAs, GaSb, InAs, InSb, AlP, AlAs, AlSb, MnS, MnSe, MgS and / or MgSe.

[0011] The shell has a thickness of about 0.5 nm to about 3 nm, and the outer shell has a thickness of about 0.5 nm to about 4 nm.

[0012] The outer shell has a thickness greater than a thickness of the shell.

[0013] The ratio of the weight of the shell to the sum of the weights of the core and the shell is equal to or greater than about 0.2 and equal to or less than about 0.8.

[0014] The quantum dots also include organic ligands and / or metal halide ligands bound to the surface of the quantum dots. The quantum dots may emit green light having a full width at half maximum (FWHM) equal to or greater than about 25 nm and equal to or less than about 60 nm and a central wavelength equal to or greater than about 500 nm and equal to or less than about 550 nm, or red light having a full width at half maximum (FWHM) equal to or greater than about 25 nm and equal to or less than about 60 nm and a central wavelength equal to or greater than about 580 nm and equal to or less than about 660 nm, and a ratio of the weight of gallium to the weight of indium in the range of about 0.2 to about 2.0.

[0015] An embodiment of the present disclosure provides a display device, the display device includes a display panel providing source light and a light control member on the display panel and including a light control layer, the light control layer including a plurality of light control parts and a separation pattern that distinguishes the plurality of light control parts from each other. At least one of the plurality of light control parts includes a quantum dot, and the quantum dot includes a core and a shell, the core includes copper, indium, gallium, silver and sulfur, the shell surrounds the core and includes zinc sulfide (ZnS). The quantum dot can emit green light, the green light having a full width at half maximum (FWHM) equal to or greater than about 25nm and equal to or less than about 60nm and a central wavelength equal to or greater than about 500nm and equal to or less than about 550nm, and the ratio of the number of moles of silver to the sum of the number of moles of silver and copper is equal to or greater than about 0.01 and equal to or less than about 0.10.

[0016] The quantum dots may emit red light having a full width at half maximum (FWHM) equal to or greater than about 25 nm and equal to or less than about 60 nm and a central wavelength equal to or greater than about 580 nm and equal to or less than about 660 nm, and a ratio of the number of moles of silver to the sum of the number of moles of silver and copper equal to or greater than about 0.01 and equal to or less than about 0.20. The light emitted from the quantum dots may have a full width at half maximum (FWHM) equal to or greater than about 25 nm and equal to or less than about 50 nm, and a ratio of the number of moles of silver to the sum of the number of moles of silver and copper equal to or greater than about 0.001 and equal to or less than about 0.05.

[0017] The core includes copper in an amount equal to or greater than about 5 wt % and equal to or less than about 20 wt %, indium in an amount equal to or greater than about 10 wt % and equal to or less than about 30 wt %, gallium in an amount equal to or greater than about 10 wt % and equal to or less than about 40 wt %, sulfur in an amount equal to or greater than about 30 wt % and equal to or less than about 60 wt %, and silver in an amount equal to or greater than about 5 wt % and equal to or less than about 30 wt %, based on about 100 wt % of the total weight of the core.

[0018] The light control member also includes a base substrate and a color filter layer including a plurality of filters transmitting light having different wavelengths.

[0019] The plurality of light-controlling portions are between the display panel and the color filter layer, and the color filter layer is between the plurality of light-controlling portions and the base substrate.

[0020] The light control part includes a first light control part transmitting the source light, a second light control part converting the source light into a second color light and emitting the second color light, and a third light control part converting the source light into a third color light and emitting the third color light.

[0021] The source light is blue light.

[0022] The second light-controlling portion and the third light-controlling portion include quantum dots.

[0023] The second color light may have a central wavelength equal to or greater than about 500 nm and equal to or less than about 550 nm, and the quantum dots may emit green light having a full width at half maximum (FWHM) equal to or greater than about 25 nm and equal to or less than about 60 nm.

[0024] The third color light has a central wavelength equal to or greater than about 580 nm and equal to or less than about 660 nm, and the quantum dots emit red light having a full width at half maximum (FWHM) equal to or greater than about 25 nm and equal to or less than about 60 nm.

[0025] The quantum dot also includes at least one outer shell surrounding the shell.

[0026] At least one shell includes ZnSe, ZnS, ZnTe, ZnO, ZnMg, ZnMgSe, ZnMgS, ZnMgAl, GaSe, GaTe, GaP, GaAs, GaSb, InAs, InSb, AlP, AlAs, AlSb, MnS, MnSe, MgS and / or MgSe.

[0027] In summary, the quantum dot includes a core including copper, indium, gallium, sulfur, and silver and a shell having a suitable or sufficient thickness, and thus exhibits high color purity and high photostability.

[0028] In summary, the display device includes quantum dots and thus has excellent display quality and excellent reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and other features of the embodiments of the present disclosure will become readily apparent by referring to the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0030] Figure 1 is a perspective view of an electronic device according to an embodiment of the present disclosure;

[0031] Figure 2 is an exploded perspective view of an electronic device according to an embodiment of the present disclosure;

[0032] Figure 3A is a view schematically showing the structure of a quantum dot according to an embodiment of the present disclosure;

[0033] Figure 3B is a view schematically showing the structure of a quantum dot according to an embodiment of the present disclosure;

[0034] Figure 4 is an enlarged plan view of a display device according to an embodiment of the present disclosure;

[0035] Figure 5 According to an embodiment of the present disclosure, Figure 4 A cross-sectional view of the display device taken along line II';

[0036] Fig. 6A is a graph showing a photoluminescence spectrum relative to the quantum dots according to Comparative Example 1;

[0037] Figure 6B is a graph showing a photoluminescence spectrum relative to the quantum dots according to Comparative Example 2;

[0038] 7A to 7D is a graph showing photoluminescence spectra of quantum dots relative to embodiments according to the present disclosure;

[0039] FIG. 8A to FIG. 8Cis a graph showing photoluminescence spectra of quantum dots relative to embodiments according to the present disclosure;

[0040] 9A to 9E is a graph showing photoluminescence spectra relative to quantum dots according to embodiments of the present disclosure; and

[0041] FIG. 10A to FIG. 10C is a graph showing photoluminescence spectra of quantum dots according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0042] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0043] In the present disclosure, it will be understood that when an element (or region, layer or portion) is referred to as being "on," "connected to" or "coupled to" another element or layer, the element (or region, layer or portion) can be directly on, directly connected to or directly coupled to the other element or layer, or intervening elements or layers may be present.

[0044] The same reference numerals always refer to the same elements. In the accompanying drawings, the thickness, proportion and size of the components may be exaggerated in order to effectively describe the technical content. As used herein, the term "and / or" may include any and all combinations of one or more related listed items.

[0045] It will be understood that, although the terms first, second, etc. can be used to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another element. Therefore, without departing from the spirit or scope of the present disclosure, the first element discussed below can be referred to as the second element. As used herein, unless the context clearly indicates otherwise, the singular form "one", "one (kind / person)" and "the (described)" are also intended to include plural forms.

[0046] For ease of description, spatially relative terms such as "under", "beneath", "lower", "above", "upper", etc. may be used herein to describe the relationship between one element or feature and another (other) elements or features as shown in the accompanying drawings.

[0047] It will also be understood that when the term "comprise" and / or its variations are used in this specification, it indicates the presence of the stated features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0048] In the present disclosure, when an element is referred to as being "directly on" another element, there are no intervening elements (such as layers, films, regions, and substrates) between them. For example, the term "directly on..." may mean that two layers or two components are provided without using an additional adhesive between them.

[0049] In this disclosure, the term "Group" refers to a Group in the IUPAC Periodic Table.

[0050] In the present disclosure, "Group II" includes Group IIA elements and Group IIB elements. As an example, the Group II element may be, but is not limited to, magnesium (Mg) and / or zinc (Zn).

[0051] In the present disclosure, "Group III" includes Group IIIA elements and Group IIIB elements. As examples, the Group III elements may be, but are not limited to, aluminum (Al), indium (In) and / or gallium (Ga).

[0052] In the present disclosure, "Group V" includes Group VA elements and Group VB elements. As examples, the Group V elements may be, but are not limited to, phosphorus (P), arsenic (As) and / or antimony (Sb).

[0053] In the present disclosure, "Group VI" includes Group VIA elements and Group VIB elements. As examples, Group VI elements may be, but are not limited to, oxygen (O), sulfur (S), selenium (Se), and / or tellurium (Te).

[0054] In the present disclosure, "Group VII" includes Group VIIA elements and Group VIIB elements. As an example, the Group VII element may be, but is not limited to, manganese (Mn).

[0055] 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. It will also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless explicitly so defined herein.

[0056] Hereinafter, quantum dots and a display device including the same according to embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0057] Figure 1 is a perspective view of an electronic device EA according to an embodiment of the present disclosure. Figure 2 is an exploded perspective view of the electronic device EA according to an embodiment of the present disclosure.

[0058] The electronic device EA may be applied to large display devices such as televisions, monitors, outdoor billboards, etc. In addition, the electronic device EA may be applied to small and / or medium-sized display devices such as personal computers, notebook computers, personal digital assistants, car navigation units, game units, smart phones, tablet computers, cameras, etc. However, these are only examples, and the electronic device EA may be applied to other suitable display devices as long as they do not depart from the concept of the present disclosure. Figure 1 A smartphone is shown as a representative example of the electronic device EA.

[0059] In some embodiments, the electronic device EA may include a foldable display device and / or a bendable display device, the foldable display device includes a folding area and a non-folding area, and the bendable display device includes at least one bending portion.

[0060] The front surface of the electronic device EA may correspond to the front surface of the display device DD and the front surface of the window WP. Therefore, the front surface of the electronic device EA, the front surface of the display device DD, and the front surface of the window WP will be assigned the same reference numeral, such as "FS".

[0061] Reference Figure 2 , the electronic device EA may include a window WP, a display device DD and a housing HAU.

[0062] The window WP may include an optically transparent insulating material (eg, an optically transparent electrically insulating material). The window WP may include a transmissive area TA and a bezel area BZA.

[0063] The transmission area TA may be an optically transparent area. Figure 1 and Figure 2 In the embodiment of the present invention, the transmission area TA may have a quadrilateral shape with rounded (compacted) vertices, however, this is only an example. The transmission area TA may have various suitable shapes and should not be particularly limited.

[0064] The frame area BZA may be an area having a relatively low light transmittance compared to 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 may surround the transmission area TA. The frame area BZA may define the shape of the transmission area TA. However, the present disclosure should not be limited to or thereby, and the frame area BZA may be adjacent to only one side of the transmission area TA or may be omitted.

[0065] The display device DD may have a configuration that substantially generates the image IM. The display device DD may be below the window WP. In the present disclosure, the term "below" may mean a direction opposite to a direction in which the display device DD displays the image IM.

[0066] The display device DD may display an image IM through the display surface IS, and a user may view the image IM through the transmissive area TA corresponding to the front surface FS of the electronic device EA. The image IM may include a still image as well as a video. Figure 1 A structure is shown in which the front surface FS is substantially parallel to a plane defined by the first direction DR1 and the second direction DR2 intersecting the first direction DR1, however, this is only an example. According to an embodiment, the front surface FS may be curved.

[0067] The third direction DR3 may indicate a normal direction of the front surface FS of the electronic device EA (e.g., a direction perpendicular to the front surface FS), for example, a direction in which the image IM is displayed in the thickness direction of the electronic device EA. In some embodiments, the front (or upper) surface and the rear (or lower) surface of each component of the electronic device EA may be distinguished from each other in the third direction DR3.

[0068] The fourth direction DR4 (refer to Figure 4 ) may be a direction between the first direction DR1 and the second direction DR2. The fourth direction DR4 may be defined in a plane substantially parallel to a plane defined by the first direction DR1 and the second direction DR2. In some embodiments, the directions indicated by the first direction DR1, the second direction DR2, the third direction DR3, and the fourth direction DR4 are opposite to each other, and therefore, the directions indicated by the first direction DR1, the second direction DR2, the third direction DR3, and the fourth direction DR4 may be changed to other directions.

[0069] The display device DD may include a display area DA and a non-display area NDA. The display area DA may be activated in response to an electrical signal. The non-display area NDA may be covered by a bezel area BZA. The non-display area NDA may be defined as being adjacent to the display area DA. The non-display area NDA may surround the display area DA.

[0070] The housing HAU may be below the display device DD. The housing HAU may accommodate the display device DD. The housing HAU may cover a portion of the display device DD, and an upper surface (e.g., display surface IS) of the display device DD may be exposed. The housing HAU may cover the side and bottom surfaces of the display device DD, and the upper surface may be completely exposed, however, the present disclosure should not be limited to or thereby. According to an embodiment, the housing HAU may cover a portion of the upper surface in addition to the side and bottom surfaces of the display device DD.

[0071] The housing HAU may protect the display device DD from external impacts and foreign objects. The housing HAU may include plastic and / or metal materials, however, this is only an example. The material used for the housing HAU should not be specifically limited as long as the material protects the display device DD from external impacts and foreign objects.

[0072] Figure 3A is a view schematically showing the structure of a quantum dot QD according to an embodiment of the present disclosure. Figure 3B Schematically shows the structure of a quantum dot QD-1 according to an embodiment of the present disclosure. Figure 3A and Figure 3B The structure, composition and properties of embodiments of quantum dots QD and QD-1 are described.

[0073] Reference Figure 3A , the quantum dot QD may include a core CO and a shell SH surrounding the core CO.

[0074] The core CO may include copper (Cu), indium (In), gallium (Ga), silver (Ag), and sulfur (S). CuInGaS may be doped with silver. 2 compounds to obtain the core CO. According to embodiments, copper (Cu) and silver (Ag) included in the core CO may be present in various suitable molar ratios.

[0075] In the present embodiment, a ratio of the mole number of copper (Cu) to the mole number of silver (Ag) constituting the core CO may be in the range of about 0.001 or more and about 0.999 or less, for example, may be about 0.01 or more and about 0.99 or less.

[0076] In this embodiment, the ratio of the weight of gallium (Ga) constituting the core CO to the weight of indium (In) may be about 0.2 or more and about 2.0 or less, for example, may be about 0.4 or more and about 1.7 or less, or may be about 0.47 or more and about 1.7 or less.

[0077] In the case of other quantum dots with a core of AgInGaS, a common approach is to grow a shell of amorphous gallium sulfide (GaS) around the core. However, the amorphous shell cannot adequately protect the core, so it is difficult to ensure the stability of the quantum dot.

[0078] In addition, in the case of CuInGaS 2 In other quantum dots with a core of a ZnS core, a common method is to grow a shell of zinc sulfide (ZnS) around the core. When the quantum dot includes a core surrounded by a shell including zinc sulfide (ZnS), the stability of the quantum dot is improved, however, in this case, the full width at half maximum (FWHM) of the quantum dot increases due to the optical properties of the core.

[0079] However, according to an embodiment of the present disclosure, the core CO may include all of silver (Ag), copper (Cu), indium (In), gallium (Ga), and sulfur (S), and the shell SH including zinc sulfide (ZnS) may be grown outside the core CO, thereby ensuring the stability of the quantum dot QD. In addition, since the core CO includes silver (Ag), the FWHM may be reduced, and thus high color reproducibility may be achieved. Therefore, the quantum dot QD may have high quantum efficiency and optical stability, and may emit light having a suitable or desired maximum photoluminescence wavelength at a narrow FWHM.

[0080] In some embodiments, the core CO may include copper (Cu) in an amount equal to or greater than about 5 wt % and equal to or less than about 20 wt %, indium (In) in an amount equal to or greater than about 10 wt % and equal to or less than about 30 wt %, gallium (Ga) in an amount equal to or greater than about 10 wt % and equal to or less than about 40 wt %, sulfur (S) in an amount equal to or greater than about 30 wt % and equal to or less than about 60 wt %, and silver (Ag) in an amount equal to or greater than about 5 wt % and equal to or less than about 30 wt %, based on the total weight of the core CO (e.g., about 100 wt %).

[0081] In some embodiments, the content of the elements included in the quantum dots QD may be measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES), however, the present disclosure should not be limited thereto or thereby.

[0082] In an embodiment in which the contents of copper (Cu), indium (In), gallium (Ga), sulfur (S), and silver (Ag) included in the core CO satisfy the above ranges, the quantum dot QD may emit high color purity green light having a central wavelength equal to or greater than about 500 nm and equal to or less than about 550 nm and a FWHM equal to or greater than about 25 nm and equal to or less than about 60 nm. According to an embodiment, the quantum dot QD may emit high color purity red light having a central wavelength equal to or greater than about 580 nm and equal to or less than about 660 nm and a FWHM equal to or greater than about 25 nm and equal to or less than about 60 nm.

[0083] The shell SH may surround the core CO. The shell SH may be outside the core CO. The shell SH may surround the core CO and may be grown to have a uniform (or substantially uniform) thickness t0. As an example, the thickness t0 of the shell SH may be in the range of about 0.5 nm to about 3 nm. However, the thickness t0 of the shell SH should not be limited thereto or thereby.

[0084] The shell SH may have a single-layer structure. As an example, the shell SH may have a single-layer structure of a single material or a single-layer structure of a plurality of different materials. Figure 3AA quantum dot QD including a shell SH having a single-layer structure is shown as a representative example. The ratio of the weight of the shell SH to the sum of the total weight of the core CO and the shell SH may be equal to or greater than about 0.2 and equal to or less than about 0.8. However, the weight ratio of the shell SH to the quantum dot QD is only an example, and the present disclosure should not be limited thereto or thereby.

[0085] The shell SH may include zinc sulfide (ZnS). Zinc sulfide (ZnS) has a lattice spacing in a range similar to the lattice spacing of the compound constituting the core CO in the quantum dot QD (including a compound of copper (Cu), indium (In) and sulfur (S)), and therefore, the shell SH may be formed of zinc sulfide (ZnS) to have a suitable or sufficient thickness outside the core CO while minimizing or reducing the impact on the core CO.

[0086] As an example, CuInS 2 The compound may have about The lattice spacing of CuGaS 2 The compound may have about lattice spacing, and the ZnS compound can have about Therefore, the shell SH including zinc sulfide (ZnS) may surround the core CO including copper (Cu), indium (In), and sulfur (S), and may have a suitable or sufficient thickness.

[0087] The quantum dot QD may include a shell SH having a suitable or sufficient thickness, and the shell SH may provide an excellent passivation effect on the core CO. Therefore, the quantum dot QD may have improved reliability and thus may have high quantum yield characteristics.

[0088] Reference Figure 3B , the quantum dot QD-1 may include a core CO, a shell SH surrounding the core CO, and at least one shell SH-O surrounding the shell SH. The core CO and shell SH of the quantum dot QD-1 correspond to the reference Figure 3A The core CO and shell SH described above, therefore, the details of the core CO and shell SH of the quantum dot QD-1 will not be repeated here.

[0089] The shell SH-O may completely surround the shell SH. Therefore, the surface of the quantum dot QD-1 may be defined by the outer surface of the shell SH-O. In the quantum dot QD-1, the shell SH may be covered by the shell SH-O and may not be exposed.

[0090] The shell SH-O may have a single-layer or multi-layer structure. As an example, the shell SH may have a single-layer structure of a single material, a single-layer structure of a plurality of different materials, or a multi-layer structure including a plurality of layers of materials different from each other. In an embodiment where the shell SH-O has a multi-layer structure, the plurality of layers may have different compositions. In some embodiments, the composition of each layer may be discontinuously changed within the shell SH-O, or may be continuously changed within the shell SH-O. Figure 3B A housing SH-O having a single-layer structure is shown as a representative example, however, the present disclosure should not be limited thereto or thereby.

[0091] The shell SH-O 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.

[0092] In the quantum dot QD-1, the shell SH may have a thickness t0 in the range of about 0.5 nm to about 3 nm, and the shell SH-O may have a thickness t1 in the range of about 0.5 nm to about 4 nm. The thickness t1 of the shell SH-O may be greater than the thickness t0 of the shell SH, however, the present disclosure should not be limited thereto or thereby.

[0093] The quantum dot QD-1 may include a shell SH and an outer shell SH-O, and may provide an excellent passivation effect on the core CO. Therefore, the quantum dot QD-1 may have excellent reliability and high quantum yield characteristics.

[0094] Reference Figure 3A and Figure 3B , the quantum dots QD and QD-1 may have average diameters QD_R and QD1_R, respectively, each of which is equal to or greater than about 5 nm and equal to or less than about 15 nm. In embodiments where the average diameter QD_R of the quantum dots QD and the average diameter QD1_R of the quantum dots QD-1 satisfy the above-mentioned diameter ranges, the quantum dots QD and QD-1 may exhibit characteristic behaviors as quantum dots and may also have excellent dispersibility. In some embodiments, since the average diameters of the quantum dots QD and QD-1 are variously selected within the above-mentioned ranges, the photoluminescence wavelength of the quantum dots QD and QD-1 and / or the semiconductor properties of the quantum dots QD and QD-1 may be appropriately changed.

[0095] In the embodiments of the present disclosure, the expression "diameter of a quantum dot" may refer to the diameter of the entire quantum dot including its core and shell.

[0096] In some embodiments, the shape of each of the quantum dots QD and QD-1 can be selected from shapes commonly used in the relevant field and should not be specifically limited. In some embodiments, the quantum dots QD and QD-1 can be spherical, pyramidal, multi-armed and / or cubic nanoparticles, nanotubes, nanowires, nanofibers, nanosheets, etc. Figure 3A and Figure 3B Quantum dots QD and QD-1, both having a spherical shape, are shown as representative examples.

[0097] In some embodiments, quantum dots QD and QD-1 may also include organic ligands and / or metal halide ligands bound (bonded) to the surfaces of quantum dots QD and QD-1. The ligands may be chemically bound (chemically bonded) to the surfaces of quantum dots QD and QD-1, and may passivate quantum dots QD and QD-1. As an example, quantum dot QD may also include ligands chemically bound to shell SH, and quantum dot QD-1 may also include ligands chemically bound to shell SH-O.

[0098] The quantum dots QD and QD-1 may emit green light. As an example, the quantum dots QD and QD-1 may emit green light having a maximum photoluminescence wavelength equal to or greater than about 500 nm and equal to or less than about 550 nm.

[0099] According to an embodiment, the quantum dots QD and QD-1 may emit red light. The quantum dots QD and QD-1 may emit red light having a maximum photoluminescence wavelength equal to or greater than about 580 nm and equal to or less than about 660 nm.

[0100] The photoluminescence wavelength of light emitted from quantum dots QD and QD-1 can be controlled by adjusting the size of the core CO, the thickness t0 of the shell SH, and the thickness t1 of the outer shell SH-O.

[0101] The quantum dots QD and QD-1 may have a full width at half maximum (FWHM) of a narrow photoluminescence wavelength spectrum, the full width at half maximum (FWHM) being equal to or greater than about 25 nm and equal to or less than about 60 nm. As an example, the quantum dots QD and QD-1 may have a FWHM of a photoluminescence wavelength spectrum being equal to or greater than about 30 nm and equal to or less than about 60 nm. In some embodiments where the FWHM of the quantum dots QD and QD-1 meets the above range, the color purity and color reproducibility of the quantum dots QD and QD-1 may be improved. In some embodiments, the light emitted by the quantum dots QD and QD-1 may travel in all (or substantially all) directions, and thus the light viewing angle may be improved.

[0102] Figure 4 is an enlarged plan view of a portion of the display device DD according to an embodiment of the present disclosure. Figure 5 According to an embodiment of the present disclosure, Figure 4 4 is a cross-sectional view of the display device DD taken along line II'.

[0103] In the following, reference is made to Figure 4 and Figure 5 An embodiment of a display device DD is described. Figure 4 and Figure 5 The display device DD shown in FIG. 1 may include the above-mentioned quantum dots.

[0104] Reference Figure 4 , the display device DD may include a non-light emitting region NPXA and light emitting regions PXA-B, PXA-G, and PXA-R. When viewed in a plane, the light emitting regions PXA-B, PXA-G, and PXA-R may be spaced apart from each other.

[0105] The light emitting regions PXA-B, PXA-G, and PXA-R may be distinguished from one another according to the color of light transmitted therethrough. Figure 4 and Figure 5 As a representative example, three light emitting regions PXA-B, PXA-G, and PXA-R emitting blue, green, and red light, respectively, are shown. As an example, the display device DD may include a blue light emitting region PXA-B, a green light emitting region PXA-G, and a red light emitting region PXA-R that are distinguished from each other.

[0106] Reference Figure 4 , the red light emitting region PXA-R may have a quadrilateral shape with vertices cut into straight lines, the green light emitting region PXA-G may have an octagonal shape, and the blue light emitting region PXA-B may have a quadrilateral shape with rounded (rounded) vertices, however, the present disclosure should not be limited thereto or thereby. According to embodiments, each of the light emitting regions PXA-B, PXA-G, and PXA-R may have various suitable polygonal shapes or circular shapes (or substantially circular shapes).

[0107] Reference Figure 4 , the blue light emitting regions PXA-B and the red light emitting regions PXA-R may be arranged alternately with each other in the first direction DR1 to form a first group PXG1. The green light emitting regions PXA-G may be arranged in the first direction DR1 to form a second group PXG2. The first group PXG1 may be spaced apart from the second group PXG2 in the second direction DR2. Each of the first group PXG1 and the second group PXG2 may be provided in plural. The first group PXG1 and the second group PXG2 may be arranged alternately with each other in the second direction DR2. One green light emitting region PXA-G may be spaced apart from one blue light emitting region PXA-B or one red light emitting region PXA-R in the fourth direction DR4. Figure 4 The light emitting regions PXA-B, PXA-G and PXA-R shown in FIG. The arrangement structure (eg, RGBG matrix, RGBG structure, or RGBG matrix structure) is arranged, but the present disclosure is not limited thereto. is an officially registered trademark of Samsung Display Co., Ltd.

[0108] However, the present disclosure should not be limited thereto or thereby, and the light emitting regions PXA-B, PXA-G, and PXA-R may be arranged in various suitable ways. For example, the light emitting regions PXA-B, PXA-G, and PXA-R may be arranged in a stripe form in which the blue light emitting regions PXA-B, the green light emitting regions PXA-G, and the red light emitting regions PXA-R are sequentially and alternately arranged in the first direction DR1, or may be arranged in a DIAMOND PIXEL pattern. TM Arrangement structure arrangement. DIAMOND PIXEL TM is a trademark of Samsung Display Co., Ltd.

[0109] Figure 5 According to an embodiment of the present disclosure, Figure 4 4 is a cross-sectional view of the display device DD taken along line II'.

[0110] Reference Figure 5 , the display device DD may include a display panel DP and a light control member PP on the display panel DP.

[0111] The display panel DP may include a base layer BS, a circuit layer DP-CL on the base layer BS, and a display element layer DP-EL on the circuit layer DP-CL.

[0112] The display panel DP may be a light-emitting type (or type) display panel. As an example, the display panel DP may be an organic electroluminescent display panel or a quantum dot light-emitting display panel, however, it should not be limited thereto or thereby. According to an embodiment, the display panel DP may be a micro LED display panel, a micro OLED display panel, a nano OLED display panel, or an LCD display panel. When the display panel DP is an LCD display panel, the display panel DP may further include a backlight unit to provide light to the LCD display panel.

[0113] The base layer BS may be disposed at the lowest position of the display panel DP. The base layer BS may provide a base surface on which components other than the base layer BS included in the display panel DP are stacked.

[0114] The base layer BS may include a synthetic resin layer and / or a glass layer. The base layer BS may include a first synthetic resin layer, a second synthetic resin layer and an inorganic layer between the first synthetic resin layer and the second synthetic resin layer. The synthetic resin layer may include a thermosetting resin. In some embodiments, the synthetic resin layer may be a polyimide resin layer, however, it should not be limited to this or thereby. The synthetic resin layer may include at least one selected from acrylic resins, methacrylic resins, polyisoprene resins, vinyl resins, epoxy resins, urethane resins, cellulose resins, siloxane resins, polyamide resins and perylene resins.

[0115] The circuit layer DP-CL may be on the base layer BS. The circuit layer DP-CL may include an insulating layer (e.g., an electrically insulating layer), a semiconductor pattern, a conductive pattern (e.g., an electrically conductive pattern), and a signal line. An insulating layer (e.g., an electrically insulating layer), a semiconductor layer, and a conductive layer (e.g., an electrically conductive layer) may be formed on the base layer BS by coating and / or deposition processes. Then, the insulating layer, the semiconductor layer, and the conductive layer may be selectively patterned by several photolithography processes. Thus, semiconductor patterns, conductive patterns, and signal lines included in the circuit layer DP-CL may be formed. The circuit layer DP-CL may include a transistor, a buffer layer, and a plurality of insulating layers (e.g., a plurality of electrically insulating layers).

[0116] The display element layer DP-EL may include a pixel defining layer PDL, a light emitting element ED, and an encapsulation layer TFE on the light emitting element ED.

[0117] The pixel defining layer PDL may be on the circuit layer DP-CL and may cover a portion of the first electrode EL1 described further below. A light emitting opening OH may be defined by the pixel defining layer PDL. At least a portion of the first electrode EL1 may be exposed through a corresponding light emitting opening OH of the pixel defining layer PDL.

[0118] The pixel defining layer PDL may be formed of a polymer resin. As an example, the pixel defining layer PDL may include a polyacrylate resin and / or a polyimide resin. In some embodiments, in addition to the polymer resin, the pixel defining layer PDL may also include an inorganic material. As an example, the pixel defining layer PDL may include silicon nitride (SiN x ), silicon oxide (SiO x ) and / or silicon oxynitride (SiO x N y). In some embodiments, the pixel defining layer PDL may include a light absorbing material and / or a black pigment and / or a dye. The pixel defining layer PDL including the black pigment and / or the dye may be a black pixel defining layer. When forming the pixel defining layer PDL, carbon black may be used as the black pigment and / or the dye, however, the present disclosure should not be limited thereto.

[0119] The pixel defining layer PDL may define the light emitting regions PXA-B, PXA-G, and PXA-R. The light emitting regions PXA-B, PXA-G, and PXA-R may be distinguished from the non-light emitting region NPXA by the pixel defining layer PDL.

[0120] The light emitting regions PXA-B, PXA-G, and PXA-R may have different sizes according to the color of the light emitted therefrom. In the present embodiment, the size may mean the size when viewed from a plane defined by the first direction DR1 and the second direction DR2. In the display device DD, the blue light emitting region PXA-B may have the largest size, and the green light emitting region PXA-G may have the smallest size, however, the present disclosure should not be limited thereto or thereby.

[0121] According to the display panel DP of the embodiment of the present disclosure, the light emitting element ED may emit source light. As an example, the source light may correspond to blue light. The light emitting element ED may include a first electrode EL1, a second electrode EL2 on the first electrode EL1, and a functional layer OL between the first electrode EL1 and the second electrode EL2.

[0122] Figure 5 The functional layer OL is schematically shown as a single layer, however, the functional layer OL may include multiple functional layers such as a hole transport region, a light emitting layer, and an electron transport region. The light emitting layer may include a host and a dopant (the dopant is an organic electroluminescent material), or may include quantum dots according to the previously described embodiments and / or any suitable quantum dots generally available in the art.

[0123] As an example, the light emitting element ED may be a light emitting element having a series structure including a plurality of light emitting stacks. Each of the light emitting stacks may include a light emitting layer. In an embodiment, the light emitted from each of the light emitting stacks may be blue light, however, the present disclosure should not be limited thereto or thereby. According to an embodiment, the light emitted from the light emitting stacks, respectively, may have wavelengths different from each other. As an example, at least one of the light emitting stacks may emit blue light, and the other light emitting stacks may emit green light. In an embodiment, the light emitting element ED may emit white light by combining a plurality of light emitting stacks emitting light in different wavelength ranges. The charge generation layer may be between light emitting stacks adjacent to each other. Therefore, when the light emitting element ED is a light emitting element having a series structure, the functional layer OL may include a plurality of light emitting stacks and a charge generation layer between the light emitting stacks.

[0124] Figure 5 The functional layer OL is shown as a single layer generally disposed throughout the light emitting regions PXA-B, PXA-G, and PXA-R, however, at least one of the layers included in the functional layer OL may be disposed to correspond to the light emitting regions PXA-B, PXA-G, and PXA-R, respectively, after being patterned by the pixel defining layer PDL.

[0125] The encapsulation layer TFE may cover the display element layer DP-EL. The encapsulation layer TFE may be a single layer or a multilayer including multiple layers stacked on each other. As an example, the encapsulation layer TFE may include a first inorganic layer, an organic layer, and a second inorganic layer stacked in sequence. However, the present disclosure should not be limited to or thereby, and the encapsulation layer TFE may also include an inorganic layer and an organic layer. The encapsulation layer TFE may protect the display element layer DP-EL from external moisture and / or oxygen. Therefore, the encapsulation layer TFE may improve the reliability of the display device DD.

[0126] The light control member PP may include a base substrate BL, a light control layer CCL under the base substrate BL, and a color filter layer CFL between the base substrate BL and the light control layer CCL, however, the present disclosure should not be limited thereto or thereby; and the color filter layer CFL may be omitted.

[0127] The base substrate BL may be disposed at the uppermost position of the light control member PP. The base substrate BL may provide a base surface on which components included in the light control member PP are stacked in addition to the base substrate BL. The base substrate BL may be a glass substrate, a metal substrate, and / or a plastic substrate, however, the present disclosure should not be limited thereto or thereby. According to an embodiment, the base substrate BL may be an inorganic layer, an organic layer, or a composite material layer.

[0128] The color filter layer CFL may be under the base substrate BL. The color filter layer CFL may include a plurality of filters CF1, CF2, and CF3 and a second barrier layer BFL2.

[0129] The first filter CF1, the second filter CF2, and the third filter CF3 may correspond to the blue light emitting region PXA-B, the green light emitting region PXA-G, and the red light emitting region PXA-R, respectively.

[0130] The first filter CF1 may transmit the first color light, the second filter CF2 may transmit the second color light, and the third filter CF3 may transmit the third color light. As an example, the first filter CF1 may be a blue filter, the second filter CF2 may be a green filter, and the third filter CF3 may be a red filter.

[0131] Each of the filters CF1, CF2 and CF3 may include a polymer photosensitive resin and a pigment and / or dye. The first filter CF1 may include a blue pigment and / or dye, the second filter CF2 may include a green pigment and / or dye, and the third filter CF3 may include a red pigment and / or dye, however, the present disclosure should not be limited to this or thereby. According to an embodiment, the first filter CF1 may include a polymer photosensitive resin, but may not include a pigment or dye. The first filter CF1 may be transparent. The first filter CF1 may be formed of a transparent photosensitive resin.

[0132] The color filter layer CFL may include a light blocking portion. The light blocking portion may be a black matrix. The light blocking portion may include an organic light blocking material and / or an inorganic light blocking material containing a black pigment and / or a dye. The light blocking portion may prevent a light leakage phenomenon from occurring (or reduce the possibility or occurrence of a light leakage phenomenon), and may define a boundary between mutually adjacent filters CF1, CF2, and CF3. In some embodiments, the light blocking portion may be formed as a blue filter. The light blocking portion may correspond to a non-luminous area NPXA.

[0133] The first filter CF1, the second filter CF2, and the third filter CF3 may overlap each other in the non-light emitting area NPXA. In some embodiments, the portions where the filters CF1, CF2, and CF3 overlap each other may prevent light leakage (or reduce the possibility or occurrence of light leakage), and the boundaries between the filters CF1, CF2, and CF3 adjacent to each other as light blocking portions may be distinguished.

[0134] The light-controlling layer CCL may include a plurality of light-controlling parts CCP1 , CCP2 , and CCP3 , a separation pattern BMP distinguishing the light-controlling parts CCP1 , CCP2 , and CCP3 from each other, and a first barrier layer BFL1 .

[0135] The separation pattern BMP may include a polymer resin and a liquid repellent additive. The separation pattern BMP may include a light absorbing material and / or a pigment and / or a dye. As an example, the separation pattern BMP may include a black pigment and / or a black dye to achieve a black separation pattern. When forming a black separation pattern, carbon black may be used as the black pigment and / or dye, however, the present disclosure should not be limited thereto.

[0136] The light-controlling parts CCP1, CCP2 and CCP3 may include a first light-controlling part CCP1 transmitting a first color light, a second light-controlling part CCP2 converting the first color light into a second color light, and a third light-controlling part CCP3 converting the first color light into a third color light.

[0137] The second color light may have a wavelength longer than the first color light, and the third color light may have a wavelength longer than the first and second color light. As an example, the first color light may be blue light, the second color light may be green light, and the third color light may be red light.

[0138] The first light-controlling part CCP1 may include a scatterer SP (eg, light scatterer SP), the second light-controlling part CCP2 may include a first quantum dot QD1 and a scatterer SP, and the third light-controlling part CCP3 may include a second quantum dot QD2 and a scatterer SP. In an embodiment, the first light-controlling part CCP1 may not include quantum dots.

[0139] Since the energy band gap can be adjusted by adjusting the size of the core or shell of the first quantum dot QD1 and the second quantum dot QD2 or the ratio of elements in the compound, various suitable wavelengths of light can be obtained. The first quantum dot QD1 can convert the first color light into the second color light, and the second quantum dot QD2 can convert the first color light into the third color light. As an example, the first quantum dot QD1 can absorb the source light with blue and can emit the second color light with green, and the second quantum dot QD2 can absorb the source light with blue and can emit the third color light with red.

[0140] Reference Figure 3A and Figure 3BThe description of the quantum dot QD and QD-1 can be applied to the first quantum dot QD1 and the second quantum dot QD2. In an embodiment, the first quantum dot QD1 and the second quantum dot QD2 may correspond to the quantum dot QD and QD-1 having an ACIGS / ZnS (Ag-Cu-In-Ga-S / ZnS) structure. The first quantum dot QD1 and the second quantum dot QD2 may improve color purity and color reproducibility within the range of the FWHM described herein for the first quantum dot QD1 and the second quantum dot QD2. In an embodiment, light emitted from the first quantum dot QD1 and the second quantum dot QD2 may travel in all (e.g., substantially all) directions, and therefore, the light viewing angle may be improved. Figure 5 A structure is shown in which the first quantum dot QD1 and the second quantum dot QD2 have similar sizes to each other. However, these are merely examples, and the present disclosure should not be limited thereto or thereby. As an example, the first quantum dot QD1 that emits light in a relatively short wavelength range may have a small average diameter compared to the second quantum dot QD2 that emits light in a relatively long wavelength range. In the present disclosure, the average diameter may correspond to the arithmetic mean of the diameters of a plurality of quantum dots. In an embodiment, the diameter of a quantum dot may be the average of the width of the quantum dot in a cross section.

[0141] The scatterer SP may be an inorganic particle. As an example, the scatterer SP may include a particle selected from TiO 2 、ZnO、Al 2 O 3 、SiO 2 and hollow silica particles. The scatterer SP may include a member selected from TiO 2 、ZnO、Al 2 O 3 、SiO 2 and hollow silica particles, or may include a member selected from TiO 2 、ZnO、Al 2 O 3 、SiO 2 and hollow silica in which two or more kinds are mixed with each other.

[0142] The first, second, and third light-control parts CCP1, CCP2, and CCP3 may further include base resins BR1, BR2, and BR3 in which quantum dots QD1 and QD2 and / or scatterers SP are dispersed. According to an embodiment, the first light-control part CCP1 may include scatterers SP dispersed in the first base resin BR1.

[0143] According to an embodiment, a blue light emitting region PXA-B corresponding to a light emitting element ED emitting blue light may have a maximum size in a display device DD, and a green light emitting region PXA-G corresponding to a light emitting element ED emitting green light may have a minimum size in a display device DD. The matrix resins BR1, BR2, and BR3 may be a medium in which quantum dots QD1 and QD2 and scatterers SP are dispersed, and may include various suitable resin compositions generally referred to as binders. As an example, the first matrix resin BR1, the second matrix resin BR2, and the third matrix resin BR3 may be an acrylic resin, a urethane resin, a siloxane resin, and / or an epoxy resin. The first matrix resin BR1, the second matrix resin BR2, and the third matrix resin BR3 may be a transparent resin. According to an embodiment, the first matrix resin BR1, the second matrix resin BR2, and the third matrix resin BR3 may be the same as or different from each other.

[0144] The first barrier layer BFL1 may cover the light control parts CCP1, CCP2, CCP3. The first barrier layer BFL1 may prevent moisture and / or oxygen (which may be referred to as moisture / oxygen hereinafter) from entering. The first barrier layer BFL1 may be on the light control parts CCP1, CCP2, and CCP3 to prevent or reduce the light control parts CCP1, CCP2, and CCP3 from being exposed to moisture / oxygen. The second barrier layer BFL2 may be between the light control parts CCP1, CCP2, and CCP3 and the plurality of filters CF1, CF2, and CF3 of the color filter layer CFL.

[0145] The barrier layers BFL1 and BFL2 may include at least one inorganic layer. In some embodiments, the barrier layers BFL1 and BFL2 may include an inorganic material. As an example, the barrier layers BFL1 and BFL2 may include silicon nitride, aluminum nitride, zirconium nitride, titanium nitride, hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide, titanium oxide, tin oxide, cerium oxide and / or silicon oxynitride and / or a metal film with light transmittance. In some embodiments, the barrier layers BFL1 and BFL2 may also include an organic layer. Each of the barrier layers BFL1 and BFL2 may include a single layer or multiple layers.

[0146] At least one of the first light-controlling part CCP1, the second light-controlling part CCP2, and the third light-controlling part CCP3 of the display device DD may include quantum dots QD and QD-1 according to an embodiment of the present disclosure (refer to Figure 3A and Figure 3B ), therefore, the display device DD may have excellent color reproducibility. In some embodiments, the display device DD including the quantum dots according to the embodiments of the present disclosure may have excellent optical characteristics and reliability.

[0147] Hereinafter, quantum dots according to embodiments of the present disclosure will be described in more detail with reference to embodiment examples and comparative examples. In addition, the embodiment examples shown below are to help understand the subject matter of the present disclosure, and the scope of the present disclosure should not be limited thereto or thereby.

[0148] Used in Fig. 6A , Figure 6B and FIG. 7A to FIG. 7B The quantum dots of Comparative Example 1 evaluated as shown in Table 1 include a core including silver (Ag), indium (In), gallium (Ga), and sulfur (S) and a shell surrounding the core and including zinc sulfide (ZnS). That is, the quantum dots of Comparative Example 1 are quantum dots having a core-shell structure of AgInGaS / ZnS.

[0149] In addition, the quantum dot of Comparative Example 2 includes a core including copper (Cu), indium (In), gallium (Ga), and sulfur (S) and a shell surrounding the core and including zinc sulfide (ZnS). That is, the quantum dot of Comparative Example 2 is a CuInGaS 2 / ZnS core-shell structured quantum dots.

[0150] Each of the quantum dots of Example 1 to Example 4 includes a core containing silver (Ag), copper (Cu), indium (In), gallium (Ga) and sulfur (S) and a shell surrounding the core and including zinc sulfide (ZnS). That is, the quantum dots of Example 1 to Example 4 are all quantum dots of a core-shell structure of Ag-Cu-In-Ga-S / ZnS. However, the ratio of the molar number of silver to copper in Example 1 to Example 4 is different from each other. In Example 1 to Example 4, the ratio of the molar number of silver to copper is 8:2, 6:4, 4:6 and 2:8, respectively.

[0151] Fig. 6A is a graph showing a photoluminescence spectrum relative to the quantum dots according to Comparative Example 1. Figure 6B is a graph showing a photoluminescence spectrum relative to the quantum dots according to Comparative Example 2. 7A to 7D is a graph showing the photoluminescence spectrum of quantum dots according to an embodiment of the present disclosure. Fig. 6A , Figure 6B as well as 7A to 7D , the vertical axis represents the normalized photoluminescence intensity, and the horizontal axis represents the photoluminescence wavelength.

[0152] exist Fig. 6A , Figure 6B as well as 7A to 7D , a curve of “core” indicated by a solid line corresponds to a case including only a core, and a curve of “shell” indicated by a dotted line corresponds to a case where the quantum dot includes a core and an outer shell surrounding the core.

[0153] Table 1 below shows the measurement results of the photoluminescence wavelength (PL) peak and FWHM of the quantum dots of the comparative example and the embodiment example.

[0154] For convenience of explanation, a value obtained by subtracting the FWHM of the quantum dots in which only the core is formed from the FWHM of the quantum dots in which the core and the shell are formed in the comparative example or the embodiment example (core / shell FWHM-core FWHM) is referred to as a "change (amount of change) in FWHM" of the comparative example or the embodiment example. In this case, "+" in front of the change in FWHM indicates an increase, and "-" in front of the change in FWHM indicates a decrease.

[0155] Table 1

[0156]

[0157]

[0158] Reference Fig. 6A As shown in Table 1, the FWHM of the "core" of Comparative Example 1 corresponds to a relatively small value (39 nm) when compared with the FWHM of the other comparative examples and the embodiment examples. However, the change (+50 nm) of the FWHM of Comparative Example 1 is relatively large compared with the change of the FWHM of the other comparative examples and the embodiment examples. In the case of Comparative Example 1, when a shell including zinc sulfide (ZnS) is grown on a core including AgInGaS, the shell does not have a sufficient thickness after growth. Because AgInS 2 Compounds and AgGaS 2 The lattice spacing of the compound is approximately Peace And the lattice spacing of ZnS compound is about Therefore, there is a difference in lattice spacing between the compound included in the core and the compound included in the shell, and therefore, gallium escapes from the core and moves to the shell. Therefore, FWHM increases, and color reproducibility of the quantum dot decreases.

[0159] Reference Figure 6B As shown in Table 1, the FWHM (99 nm) of the "core" of Comparative Example 2 corresponds to a relatively large value. However, the change in FWHM of Comparative Example 2 (-16 nm) is relatively smaller than the change in FWHM of Comparative Example 1 and Example 1 and Example 2. As described above, because CuInS 2 Compounds and CuGaS 2 The lattice spacing of the compound is approximately Peace And the lattice spacing of ZnS compound is about Therefore, the lattice spacing of the compound included in the core is similar to the lattice spacing of the compound included in the shell. Therefore, the compound included in the core does not move, and thus, the shell can have a sufficient thickness after growth.

[0160] That is, the quantum dot including the core containing the AgInGaS compound as Comparative Example 1 has a narrow FWHM, however, it is difficult to form a ZnS shell. 2 In the case of a quantum dot having a core of a compound, the FWHM of the core is large, however, the zinc sulfide shell surrounding the core has a sufficient thickness after growth. Therefore, even after the shell around the core grows, the change in FWHM can be small, and the FWHM decreases.

[0161] The quantum dots of Example 1 to Example 4 include a core including silver, copper, indium, gallium and sulfur and a shell surrounding the core and including zinc sulfide (ZnS). Unlike the quantum dots of Comparative Examples 1 and 2, the quantum dots of Example 1 to Example 4 include a core including both silver and copper. That is, the quantum dots of Example 1 to Example 4 may be quantum dots having a core-shell structure including Ag / Cu / In / Ga / S as a core and ZnS as a shell.

[0162] Reference 7A to 7D and Table 1, the cores of Embodiment Examples 1 to 4 have FWHM (nm) of 76 nm, 77 nm, 64 nm, and 54 nm, respectively, which are smaller than the FWHM (99 nm) of the quantum dots including only the core of Comparative Example 2.

[0163] Furthermore, the variation in FWHM of Embodiment Examples 1 to 3 increases, but is smaller than the variation (+50 nm) in FWHM of Comparative Example 1. Furthermore, the variation in FWHM of Embodiment Example 4 corresponds to an increase of +10 nm.

[0164] Reference Fig.7D As shown in Table 1, even if a shell is further formed on the core, the change in the photoluminescence wavelength of the quantum dot of Example 4 is small. That is, the stability of the shell is sufficiently ensured, and the characteristics of the core of the quantum dot are well maintained.

[0165] According to an embodiment of the present disclosure, the core includes all of copper, indium, gallium, sulfur, and silver, and thus has a small FWHM. In addition, since the quantum dot includes the above-mentioned core, the shell including zinc sulfide can be properly or fully grown, and therefore, the change in FWHM between the case of including the shell and the case of not including the shell is small.

[0166] Therefore, in the case where the quantum dots according to the embodiment of the present disclosure are included in the display device DD (refer to Figure 5) in the light control parts CCP1, CCP2 and CCP3 (refer to Figure 5 ) in the case, excellent color reproducibility and reliability can be ensured.

[0167] FIG. 8A to FIG. 8C is a graph showing the photoluminescence spectrum of quantum dots according to an embodiment of the present disclosure. FIG. 8A to FIG. 8C Together with Table 2, the characteristics of the quantum dots of Embodiment Examples 5 to 7 will be described.

[0168] The quantum dots of Example 5 to Example 7 may correspond to the reference FIG. 3A to FIG. 3B The quantum dots QD and QD-1 described. That is, the quantum dots of Example 5 to Example 7 may be quantum dots including Ag / Cu / In / Ga / S as a core and ZnS as a shell.

[0169] The composition ratios (molar ratios) of silver, copper, indium, gallium, and sulfur contained in each core included in the quantum dots of Embodiment Examples 5 to 7 are as follows.

[0170] Composition ratio of the core of Example 5: Ag 0.01 Cu 0.99 In 0.2 Ga 0.8 S 2 .

[0171] Composition ratio of the core of Example 6: Ag 0.03 Cu 0.97 In 0.2 Ga 0.8 S 2 .

[0172] Composition ratio of the core of Example 7: Ag 0.1 Cu 0.9 In 0.35 Ga 0.65 S 2 .

[0173] The photoluminescence wavelength can be adjusted by adjusting the size of the quantum dot particles of Example 5 to Example 7. As an example, the core of the quantum dot of Example 5 has a diameter of about 1.6 nm to about 3.2 nm, and the quantum dot of Example 5 has a diameter of about 3.2 nm to about 5.2 nm. The diameter of the quantum dot corresponds to the total diameter including the core and the shell.

[0174] The core of the quantum dot of Example 6 has a diameter of about 1.8 nm to about 3.2 nm, and the quantum dot of Example 6 has a diameter of about 3.3 nm to about 5.7 nm. The core of the quantum dot of Example 7 has a diameter of about 1.7 nm to about 2.9 nm, and the quantum dot of Example 7 has a diameter of about 3.2 nm to about 5.4 nm.

[0175] Each of the quantum dots according to the present embodiment may correspond to a quantum dot emitting green light having a FWHM equal to or greater than about 25 nm and equal to or less than about 60 nm.

[0176] Table 2 below shows the photoluminescence wavelength (PL) peak, FWHM, photoluminescence quantum yield (PLQY), and photostability of quantum dots of Example Examples 5 to 7.

[0177] Photoluminescence quantum yield (PLQY) refers to the ratio of the number of photons emitted by a material to the number of photons absorbed by the material, and the higher the PLQY, the more efficiently the material can emit the energy it has absorbed. In an embodiment, photostability refers to the ability of a quantum dot to retain its luminescent properties over time when exposed to light.

[0178] In the embodiments of the present disclosure, the photoluminescence quantum yield (PLQY) and photostability of the quantum dots of the embodiment examples are measured by "QE-2100", which is a device developed by Donga Otsuka TM Provides quantum efficiency measurement equipment.

[0179] In an embodiment, when measuring the photoluminescence quantum yield, a reference solution is placed in an integrating sphere and irradiated with light having a wavelength of about 450 nm to collect the photoluminescence spectrum, and similarly, a sample solution containing quantum dots according to an embodiment of the present disclosure is placed in an integrating sphere and irradiated with light having a wavelength of about 450 nm to collect the photoluminescence spectrum. Compared with the reference solution, the intensity of the light source spectrum decreases the amount absorbed in the sample solution, and compared with the reference spectrum, the intensity of the emitted light increases. In an embodiment, the reduced or increased intensity of the light source spectrum is converted into the number of photons using the spectral intensity of the wavelength of the integrating sphere to calculate the photoluminescence quantum yield.

[0180] In an embodiment, when measuring photostability, the initial photon conversion efficiency (PCE) is measured after producing a polymer film containing about 30 wt % of quantum dots according to an embodiment of the present disclosure, and the value of the photon conversion efficiency that changes by irradiating the polymer film with about 200 nits of blue light for 1500 hours is measured. The blue light used to measure photostability has a photoluminescence wavelength of about 450 nm.

[0181] Table 2 below shows the photoluminescence wavelength (PL) peak, FWHM, photoluminescence quantum yield (PLQY), and photostability of quantum dots of Example Examples 5 to 7.

[0182] Table 2

[0183]

[0184]

[0185] Referring to Table 2, each of the quantum dots of Example 5 to Example 7 has a full width at half maximum (FWHM) equal to or less than about 60nm. In more detail, because the full width at half maximum (FWHM) is equal to or less than about 55nm, the quantum dots according to the embodiments of the present disclosure can exhibit high color purity compared to Comparative Examples 1 and 2. In an embodiment, the quantum dots of Example 5 to Example 7 correspond to test examples in which the composition ratio (molar ratio) of gallium to indium is set high and the size of the quantum dots is adjusted. Therefore, it is observed that the quantum dots of Example 5 to Example 7 have a large band gap equal to or greater than about 500nm and equal to or less than about 550nm.

[0186] 9A to 9E is a graph showing the photoluminescence spectrum of quantum dots according to an embodiment of the present disclosure. 9A to 9E Together with Table 3, the characteristics of the quantum dots of Embodiment Examples 8 to 12 will be described.

[0187] The quantum dots of Example 8 to Example 12 may correspond to the reference FIG. 3A to FIG. 3B The quantum dots QD and QD-1 described. That is, the quantum dots of Example 8 to Example 12 may be quantum dots including Ag / Cu / In / Ga / S as a core and ZnS as a shell.

[0188] The composition ratios (molar ratios) of silver, copper, indium, gallium, and sulfur contained in each core included in the quantum dots of Embodiment Example 8 to Embodiment Example 12 are as follows.

[0189] Composition ratio of the core of Example 8: Ag 0.01 Cu 0.99 In 0.3 Ga 0.7 S 2 .

[0190] Composition ratio of the core of Example 9: Ag 0.03 Cu 0.97 In 0.4 Ga 0.6 S 2 .

[0191] Composition ratio of the core of Example 10: Ag 0.05 Cu 0.95 In 0.4 Ga 0.6 S 2 .

[0192] Composition ratio of the core of Example 11: Ag 0.1 Cu 0.9 In 0.35 Ga 0.65 S 2 .

[0193] Composition ratio of the core of Example 12: Ag 0.2 Cu 0.8 In 0.3 Ga 0.7 S 2 .

[0194] The photoluminescence wavelength may be adjusted by adjusting the particle size of the quantum dots of Example 8 to Example 12.

[0195] The core of the quantum dot of Example 8 has a diameter of about 3.8nm to about 5.8nm, and the quantum dot of Example 8 has a diameter of about 5.5nm to about 7.9nm. The core of the quantum dot of Example 9 has a diameter of about 4.4nm to about 6.6nm, and the quantum dot of Example 9 has a diameter of about 5.8nm to about 8.6nm. The core of the quantum dot of Example 10 has a diameter of about 4.4nm to about 6.4nm, and the quantum dot of Example 10 has a diameter of about 6.2nm to about 9.2nm. The core of the quantum dot of Example 11 has a diameter of about 4.4nm to about 6.6nm, and the quantum dot of Example 11 has a diameter of about 6.2nm to about 9.0nm. The core of the quantum dot of Example 12 has a diameter of about 4.7nm to about 6.7nm, and the quantum dot of Example 11 has a diameter of about 6.6nm to about 9.8nm.

[0196] Each of the quantum dots according to the present embodiment may correspond to a quantum dot emitting red light having a FWHM equal to or less than about 60 nm.

[0197] Table 3 below shows the photoluminescence wavelength (PL) peak, FWHM, photoluminescence quantum yield (PLQY), and photostability of quantum dots of Example Examples 8 to 12.

[0198] Table 3

[0199]

[0200] Referring to Table 3, each of the quantum dots of Example 8 to Example 12 has a full width at half maximum (FWHM) equal to or less than about 60 nm. In more detail, the full width at half maximum (FWHM) corresponds to a narrow FWHM of about 50 nm or less compared to Comparative Examples 1 and 2, and exhibits high color purity. Referring to the photoluminescence wavelength of Example 8 to Example 12, when the ratio of indium to gallium is adjusted under the condition that the diameter of the quantum dot is equal to or greater than about 5 nm, it is observed that as the ratio of indium to gallium increases, quantum dots having a small band gap value equal to or greater than about 580 nm and equal to or less than about 660 nm are formed.

[0201] In addition, referring to the FWHM of Embodiment Examples 8 to 12, when the mole number of silver was set in the range of about 1% to about 20% of the mole number of copper, it was observed that the FWHM had a small value equal to or less than about 50 nm.

[0202] FIG. 10A to FIG. 10C is a graph showing the photoluminescence spectrum of quantum dots according to an embodiment of the present disclosure. FIG. 10A to FIG. 10C Together with Table 4, the characteristics of the quantum dots of Embodiment Examples 13 to 15 will be described.

[0203] The quantum dots of Example 13 to Example 15 may correspond to the reference FIG. 3A to FIG. 3B The quantum dots QD and QD-1 described. That is, the quantum dots of Example 13 to Example 15 may be quantum dots including Ag / Cu / In / Ga / S as a core and ZnS as a shell.

[0204] The composition ratio (molar ratio) of silver, copper, indium, gallium and sulfur contained in each core included in the quantum dots of Example 13 to Example 15 is as follows. When compared with the quantum dots of Example 8 to Example 12, the quantum dots of Example 13 to Example 15 correspond to the case where the ratio of silver contained in the core is set to be smaller. That is, the quantum dots of Example 13 to Example 15 are prepared under the condition that the core contains a very small amount of silver.

[0205] Composition ratio (molar ratio) of the core of Example 13: Ag 0.001 Cu 0.999 In 0.3 Ga 0.7 S 2 .

[0206] Composition ratio (molar ratio) of the core of Example 14: Ag 0.002 Cu 0.998 In 0.3 Ga 0.7 S 2 .

[0207] Composition ratio (molar ratio) of the core of Example 15: Ag 0.005 Cu 0.995 In 0.2 Ga 0.8 S 2 .

[0208] Table 4 below shows the composition ratios (weight ratios) of silver, copper, indium, gallium, and sulfur contained in each core included in the quantum dots of Embodiment Examples 13 to 15. The weight ratios in Table 4 below are rounded off after the decimal point and expressed to 3 digits.

[0209] Table 4

[0210]

[0211] The core of the quantum dot of Example 13 has a diameter of about 5.8 nm to about 7.6 nm, and the quantum dot of Example 13 has a diameter of about 7.4 nm to about 9.8 nm. The core of the quantum dot of Example 14 has a diameter of about 5.6 nm to about 7.4 nm, and the quantum dot of Example 14 has a diameter of about 7.9 nm to about 10.1 nm. The core of the quantum dot of Example 15 has a diameter of about 3.9 nm to about 5.1 nm, and the quantum dot of Example 15 has a diameter of about 5.0 nm to about 7.0 nm. Table 5 below shows the photoluminescence wavelength (PL) peak, FWHM, photoluminescence quantum yield (PLQY) and photostability of the quantum dots of Example 13 to Example 15.

[0212] Table 5

[0213]

[0214] Referring to Table 5, each of the quantum dots of Example 13 to Example 15 has a full width at half maximum (FWHM) equal to or less than about 60 nm. In more detail, compared with Comparative Examples 1 and 2, the full width at half maximum (FWHM) corresponds to a narrow FWHM of about 50 nm or less, and exhibits high color purity.

[0215] Although the embodiments of the present disclosure have been described, it is understood that the present disclosure should not be limited to these embodiments, but a person skilled in the art may make various changes and modifications within the spirit and scope of the present disclosure as claimed. Therefore, the disclosed subject matter should not be limited to any single embodiment described herein, and the scope of the present disclosure should be determined according to the attached claims and their equivalents.

Claims

1. A quantum dot, comprising: core, including copper, indium, gallium, silver, and sulfur; as well as A shell surrounds the core and includes zinc sulfide.

2. The quantum dot according to claim 1, wherein The quantum dot emits green light having a central wavelength equal to or greater than 500 nm and equal to or less than 550 nm, and the quantum dot including the core and the shell has a diameter equal to or greater than 2 nm and equal to or less than 4 nm, and a ratio of the number of moles of the silver to the sum of the number of moles of the silver and the copper is equal to or greater than 0.001 and equal to or less than 0.

200.

3. The quantum dot according to claim 1, wherein The quantum dot emits red light having a central wavelength equal to or greater than 580 nm and equal to or less than 660 nm, and the quantum dot including the core and the shell has a diameter equal to or greater than 5 nm and equal to or less than 10 nm, and a ratio of the number of moles of the silver to the sum of the number of moles of the silver and the copper is equal to or greater than 0.001 and equal to or less than 0.

200.

4. The quantum dot according to claim 1, wherein Light emitted from the quantum dots has a full width at half maximum of equal to or greater than 25 nm and equal to or less than 60 nm.

5. The quantum dot of claim 1 , further comprising at least one shell surrounding the shell, and wherein the at least one shell comprises ZnSe, ZnS, ZnTe, ZnO, ZnMg, ZnMgSe, ZnMgS, ZnMgAl, GaSe, GaTe, GaP, GaAs, GaSb, InAs, InSb, AlP, AlAs, AlSb, MnS, MnSe, MgS and / or MgSe.

6. The quantum dot according to claim 5, wherein The shell has a thickness of 0.5 nm to 3 nm, and the outer shell has a thickness of 0.5 nm to 4 nm.

7. The quantum dot according to claim 5, wherein The outer shell has a thickness greater than a thickness of the shell.

8. The quantum dot according to claim 1, wherein A ratio of the weight of the shell to the sum of the weights of the core and the shell is equal to or greater than 0.2 and equal to or less than 0.

8. 9 . The quantum dot according to claim 1 , further comprising an organic ligand and / or a metal halide ligand bound to a surface of the quantum dot.

10. The quantum dot according to claim 1, wherein The quantum dots emit green light having a half-width at half maximum of equal to or greater than 25 nm and equal to or less than 60 nm and a central wavelength of equal to or greater than 500 nm and equal to or less than 550 nm, or red light having a half-width at half maximum of equal to or greater than 25 nm and equal to or less than 60 nm and a central wavelength of equal to or greater than 580 nm and equal to or less than 660 nm, and a ratio of the weight of the gallium to the weight of the indium is in the range of 0.2 to 2.

0.

11. A display device, comprising: A display panel, providing source light; as well as A light control member is on the display panel and includes a light control layer, the light control layer includes a plurality of light control parts and a separation pattern that distinguishes the plurality of light control parts from each other, at least one of the plurality of light control parts includes a quantum dot, wherein the quantum dot includes a core containing copper, indium, gallium, silver and sulfur and a shell surrounding the core and including zinc sulfide.

12. The display device according to claim 11, wherein: The quantum dots emit green light having a half-width at half maximum of 25 nm or more and 60 nm or less and a central wavelength of 500 nm or more and 550 nm or less, and a ratio of the number of moles of the silver to the sum of the number of moles of the silver and the copper is 0.01 or more and 0.10 or less.

13. The display device according to claim 11, wherein: The quantum dots emit red light having a half-width at half maximum of 25 nm or more and 60 nm or less and a central wavelength of 580 nm or more and 660 nm or less, and a ratio of the number of moles of silver to the sum of the number of moles of silver and the copper is 0.01 or more and 0.20 or less.

14. The display device according to claim 11, wherein: Light emitted from the quantum dots has a half-maximum full width equal to or greater than 25 nm and equal to or less than 50 nm, and a ratio of the number of moles of the silver to the sum of the number of moles of the silver and the copper is equal to or greater than 0.001 and equal to or less than 0.

05.

15. The display device according to claim 11, wherein: The core includes, based on 100wt% of the total weight of the core, 5wt% or more and 20wt% or less of the copper, 10wt% or more and 30wt% or less of the indium, 10wt% or more and 40wt% or less of the gallium, 30wt% or more and 60wt% or less of the sulfur, and 5wt% or more and 30wt% or less of the silver.

16. The display device according to claim 11, wherein: The light control member further includes a base substrate and a color filter layer including a plurality of filters transmitting light having different wavelengths, the plurality of light control portions being located between the display panel and the color filter layer, and the color filter layer being located between the plurality of light control portions and the base substrate.

17. The display device according to claim 11, wherein: The plurality of light control parts each include: A first light control portion, transmitting the source light; a second light control section that converts the source light into a second color light and emits the second color light; and a third light control section, converting the source light into a third color light and emitting the third color light, Wherein, the source light is blue light, and the second light control part and the third light control part include the quantum dots.

18. The display device according to claim 17, wherein: The second color light is green light having a central wavelength equal to or greater than 500 nm and equal to or less than 550 nm, and the quantum dot emits green light having a half-width equal to or greater than 25 nm and equal to or less than 60 nm.

19. The display device according to claim 17, wherein: The third color light has a central wavelength equal to or greater than 580 nm and equal to or less than 660 nm, and the quantum dot emits red light having a half-maximum full width equal to or greater than 25 nm and equal to or less than 60 nm.

20. The display device according to claim 11, wherein: The quantum dot also includes at least one shell surrounding the shell, and the at least one shell includes ZnSe, ZnS, ZnTe, ZnO, ZnMg, ZnMgSe, ZnMgS, ZnMgAl, GaSe, GaTe, GaP, GaAs, GaSb, InAs, InSb, AlP, AlAs, AlSb, MnS, MnSe, MgS and / or MgSe.

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