Quantum dot composite, method of manufacturing quantum dot composite, and display device including quantum dot composite

Abstract

A quantum dot composite according to an embodiment of the present invention comprises: a quantum dot; and a ligand bonded to a surface of the quantum dot, wherein the ligand bonded to the plurality of bonding portions is provided on the surface of the quantum dot. And the combination part comprises a first combination part and a second combination part. The ligand comprises a first ligand bound to the first binding part and a second ligand bound to the second binding part, the second ligand comprises a halogen element, and the content of the halogen element is 1 to 12 at% relative to the total amount of the quantum dot compound.

Description

Technical Field

[0001] The present disclosure relates to a quantum dot complex, a method of manufacturing the quantum dot complex, and a display device including the quantum dot complex. Background Art

[0002] Various display devices are being developed for use in multimedia devices such as, for example, televisions, mobile phones, tablet computers, navigation devices, and gaming machines.

[0003] In some cases, such display devices may use self-emitting display elements that can achieve display by emitting light from a light-emitting material containing an organic compound.

[0004] Techniques for improving the color reproducibility of display devices are needed. Summary of the Invention

[0005] Embodiments of the present disclosure support quantum dot complexes with improved luminous efficiency. Embodiments of the present disclosure provide methods for producing quantum dot complexes with a simplified manufacturing process.

[0006] Embodiments of the present disclosure provide display devices with improved luminous efficiency.

[0007] A quantum dot complex according to an embodiment includes quantum dots; and ligands bound to the surface of the quantum dots, wherein a plurality of coupling parts are provided on the surface of the quantum dots, and the ligands are bound to the plurality of coupling parts, and the plurality of coupling parts include a first coupling part and a second coupling part. The ligands include: a first ligand bound to the first coupling part and a second ligand bound to the second coupling part. The second ligand contains a halogen element, and the halogen element is included in an amount of 1 at% to 12 at% relative to the total content of the quantum dot complex.

[0008] The halogen element is one of the following: chlorine, which is included in an amount of 5 at% to 7 at% relative to the total content of the quantum dot complex; bromine, which is included in an amount of 2 at% to 4 at% relative to the total content of the quantum dot complex; iodine, which is included in an amount of 1 at% to 2 at% relative to the total content of the quantum dot complex; and fluorine, which is included in an amount of 9 at% to 12 at% relative to the total content of the quantum dot complex.

[0009] The quantum dot complex may have an organic content of 10 at% or more than 10 at% relative to the total content of the quantum dot complex.

[0010] The quantum dot complex can emit red light, and the valence band value of the quantum dot complex can be from -5.60 eV to -5.80 eV.

[0011] The quantum dot complex can emit green light, and the valence band value of the quantum dot complex can be from -5.73 eV to -5.93 eV.

[0012] The quantum dot complex can emit blue light, and the valence band value of the quantum dot complex can be from -5.78 eV to -5.98 eV.

[0013] The plurality of linking portions may further include a third linking portion, and the ligand may further include a third ligand bound to the second linking portion or the third linking portion.

[0014] The third ligand may include any one selected from phosphine and phosphine oxide.

[0015] The third ligand may be a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted mercapto group, a substituted or unsubstituted oxy group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms.

[0016] The quantum dot may include a core and a shell surrounding the core.

[0017] The plurality of linking portions may be disposed on the surface of the shell.

[0018] The core may include a first semiconductor nanocrystal, the shell may include a second semiconductor nanocrystal different from the first semiconductor nanocrystal, and each of the first semiconductor nanocrystal and the second semiconductor nanocrystal may be selected from II-VI group compounds, III-V group compounds, IV-VI group compounds, group IV elements, group IV compounds, and combinations thereof.

[0019] The display device according to an embodiment includes a first electrode, a light-emitting layer positioned on the first electrode, and a second electrode positioned on the light-emitting layer, wherein the light-emitting layer includes a quantum dot complex. The quantum dot complex includes quantum dots; and ligands bound to the surface of the quantum dots, wherein a plurality of linking portions are provided on the surface of the quantum dots, the ligands are bound to the plurality of linking portions, and wherein the plurality of linking portions include a first linking portion and a second linking portion. The ligands include: a first ligand bound to the first linking portion and a second ligand bound to the second linking portion. The second ligand includes a halogen element, and the halogen element is included in an amount of 1 at% to 12 at% with respect to the total content of the quantum dot complex.

[0020] The halogen element may be one of chlorine, fluorine, iodine, and bromine. Based on the total content of the quantum dot complex, the chlorine may be included in an amount of 5 at% to 7 at%; and based on the total content of the quantum dot complex, the bromine may be included in an amount of 2 at% to 4 at%; based on the total content of the quantum dot complex, the iodine may be included in an amount of 1 at% to 2 at%; and based on the total content of the quantum dot complex, the fluorine may be included in an amount of 9 at% to 12 at%.

[0021] With respect to the total content of the quantum dot complex, the quantum dot complex may have an organic content of 10 at% or greater than 10 at%.

[0022] When the quantum dot complex emits red light, the quantum dot complex may have a valence band value of -5.60 eV to -5.80 eV, and when the quantum dot complex emits green light, the quantum dot complex may have a valence band value of -5.73 eV to -5.93 eV, and when the quantum dot complex emits blue light, the valence band value of the quantum dot complex may be -5.78 eV to -5.98 eV.

[0023] A method for manufacturing a quantum dot complex according to an embodiment includes: providing quantum dots and a first ligand bound to the surface of the quantum dots, and mixing and purifying the quantum dot complex in a first solution, wherein the first solution contains MX, wherein in the MX, M is any one of Na, Mg, K, Ca, Zn, In, Ga, Sn, and Sb, and X is any one of F, Cl, Br, and I, and when mixing and purifying the quantum dot complex with the first solution, a second ligand is bound to the surface of the quantum dots, and the second ligand includes the X.

[0024] The first solution may include a polar solvent, and the polar solvent may be methanol, ethanol, phenol, benzenediol, ethylene glycol, glycerol, diethylene glycol, triethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, or a combination thereof.

[0025] The MX may be provided at a concentration of 0.1 M to 0.5 M.

[0026] The method may further include: performing a surface treatment related to binding a third ligand to the surface of the quantum dot before mixing and purifying the quantum dot complex in the first solution.

[0027] According to an embodiment, a quantum dot complex with improved luminescence efficiency may be provided.

[0028] In some aspects, by a manufacturing method of a quantum dot complex having a simplified manufacturing process, the manufacturing cost and time related to manufacturing can be reduced.

[0029] In some aspects, a display device with improved luminescence efficiency may be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a schematic diagram of a quantum dot complex according to an embodiment.

[0031] Figure 2 is a cross-sectional view of a quantum dot complex according to an embodiment.

[0032] Figure 3 , Figure 4 and Figure 5 are each an enlarged cross-sectional view of a part of a quantum dot complex according to an embodiment.

[0033] Figure 6 is a cross-sectional view of a quantum dot complex according to another embodiment.

[0034] Figure 7 is an enlarged cross-sectional view of a part of a quantum dot complex according to another embodiment.

[0035] Figure 8 is a schematic cross-sectional view of a light-emitting device according to an embodiment.

[0036] Figure 9 is a schematic cross-sectional view of a display device according to an embodiment.

[0037] Figure 10 is a flowchart of a manufacturing process of a quantum dot complex according to an embodiment.

[0038] Figure 11 is according to Figure 10Schematic diagram of the manufacturing process of the quantum dot complex.

[0039] Figure 12 FIG. is a flowchart of the manufacturing process of the quantum dot complex according to an embodiment.

[0040] Figure 13 is according to Figure 12 Schematic diagram of the manufacturing process of the quantum dot complex. Detailed Description

[0041] Hereinafter, with reference to the accompanying drawings, various embodiments supported by aspects of the present disclosure will be described in detail so that those skilled in the art can easily implement the exemplary embodiments supported by the present disclosure.

[0042] The exemplary embodiments described herein may be in different forms and are not limited to the embodiments set forth herein.

[0043] To clearly describe the exemplary embodiments supported by the present disclosure, some parts are omitted to prevent interference with the description, and the same reference numerals are assigned to the same or similar components throughout the description.

[0044] For ease of explanation, the dimensions and thicknesses of each component shown in the drawings are arbitrarily shown, and the exemplary embodiments described herein are not necessarily limited to the dimensions and thicknesses described herein.

[0045] In the drawings, the thicknesses are shown enlarged to clearly represent the various layers and regions.

[0046] In the drawings, for ease of explanation, the thicknesses of some layers and regions are enlarged.

[0047] When a component such as a layer, film, region, or plate is referred to as being "above" or "on" another component, this includes the case where the component is "directly on" the other component, and also includes the case where there are other components between the component and the other component.

[0048] Conversely, when a component is referred to as being "directly on" another component, there is no intervening component between the component and the other component. Conversely, a reference to a component being "directly on" another component means that there are no other components between the component and the other component.

[0049] A reference to a component being "above" or "on" a reference component may mean being located above or below the reference component, and is not necessarily limited to being "above" or "on" the reference component in the opposite direction of gravity.

[0050] Throughout the specification, unless otherwise specified, a reference to a component that is referred to as "including" a component means that the component may further include other components without excluding other components.

[0051] Throughout the specification, a reference to a "planar image" means when the target portion is viewed from above, and a reference to a "cross-sectional image" means when the cross-section of the target portion cut perpendicularly is viewed from the side.

[0052] Considering the measurements discussed and the errors associated with the measurements of specific quantities, the terms "about" or "approximately" as used herein include the specified value and include a suitable range of deviations from the specific value as determined by a person of ordinary skill in the art. The term "about" may mean within one or more standard deviations, or for example within ±30%, ±20%, ±10%, ±5% of the specified value.

[0053] Aspects of the present disclosure support the development of display devices using quantum dots as light-emitting materials, which can improve the color reproducibility of display devices. Embodiments of the present disclosure support improving the luminous efficiency and service life of display devices using quantum dots.

[0054] Hereinafter, a quantum dot complex according to an embodiment will be described with reference to Figures 1 to 5 description.

[0055] Figure 1 is a schematic diagram of a quantum dot complex according to an embodiment, Figure 2 is a cross-sectional view of a quantum dot complex according to an embodiment, and Figure 3 , Figure 4 and Figure 5 are enlarged cross-sectional views of parts of a quantum dot complex according to an embodiment.

[0056] Referring to Figure 1 and Figure 2 , a quantum dot complex QDC according to an embodiment may include a quantum dot QD and a ligand LD bound to the surface of the quantum dot QD.

[0057] The quantum dot complex QDC may include a ligand LD containing a functional group. In some embodiments, the ligand LD is attached to the surface of the quantum dot QD and may have modified surface properties.

[0058] The quantum dot complex QDC may be referred to as a surface-modified quantum dot.

[0059] The quantum dot QD may include a core CR and a shell SL surrounding the core CR.

[0060] However, embodiments supported by the present disclosure are not limited thereto, and the quantum dot QD may have a single-layer structure or multiple shells.

[0061] In the examples described herein, the quantum dot may be a Group II-VI compound, a Group III-V compound, a Group IV-VI compound, a Group IV element or compound, a Group I-III-VI compound, a Group II-III-VI compound, a Group I-II-IV-VI compound, or a combination thereof.

[0062] The Group II-VI compound may be: a binary compound selected from the group consisting of CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and mixtures thereof; a ternary compound selected from the group consisting of AgInS, CuInS, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, and mixtures thereof. The Group II-VI compound may be a quaternary compound selected from the group consisting of HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and mixtures thereof.

[0063] The Group II-VI compound may further comprise a Group III metal.

[0064] The III-V compounds can be: binary compounds selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and mixtures thereof; ternary compounds selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InNP, InNAs, InNSb, InPAs, InZnP, InPSb, and mixtures thereof; or quaternary compounds selected from the group consisting of GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, InZnP, and mixtures thereof.

[0065] The III-V compounds can further include Group II metals (e.g., InZnP).

[0066] The IV-VI compounds can be: binary compounds selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, and mixtures thereof; ternary compounds selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and mixtures thereof, and the IV-VI compounds can be selected from the group consisting of quaternary compounds selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe, and mixtures thereof.

[0067] The Group IV element or Group IV compound can be a single-element compound selected from the group consisting of Si, Ge, and combinations thereof, and the Group IV element or Group IV compound can be selected from the group consisting of binary compounds selected from the group consisting of SiC, SiGe, and combinations thereof, but not limited thereto.

[0068] Examples of the I-III-VI compounds include AgInGaS, CuInSe2, CuInS2, CuInGaSe, and CuInGaS, but the I-III-VI compounds are not limited thereto.

[0069] Examples of the I-II-IV-VI compounds include, but are not limited to, CuZnSnSe and CuZnSnS.

[0070] Group IV elements or Group IV compounds are elements selected from the group consisting of Si, Ge, and mixtures thereof; the Group IV elements or Group IV compounds may be selected from the group consisting of binary compounds selected from the group consisting of SiC, SiGe, and mixtures thereof.

[0071] II-III-VI group compounds may be selected from the group consisting of ZnGaS, ZnAlS, ZnInS, ZnGaSe, ZnAlSe, ZnInSe, ZnGaTe, ZnAlTe, ZnInTe, ZnGaO, ZnAlO, ZnInO, HgGaS, HgAlS, HgInS, HgGaSe, HgAlSe, HgInSe, HgGaTe, HgAlTe, HgInTe, MgGaS, MgAlS, MgInS, MgGaSe, MgAlSe, MgInSe, and combinations thereof, but are not limited thereto.

[0072] I-II-IV-VI group compounds may be selected from CuZnSnSe and CuZnSnS, but are not limited thereto.

[0073] In the quantum dots, the aforementioned binary compounds, ternary compounds, and / or quaternary compounds may be present in the particles at a uniform concentration or may be present in the same particle with a partially different concentration distribution.

[0074] In some embodiments, one quantum dot may have a core / shell structure surrounding another quantum dot.

[0075] The interface between the core and the shell may have a concentration gradient, where the concentration of the elements present in the shell decreases towards the center.

[0076] In some embodiments, the quantum dot may have a core-shell structure including a core containing the aforementioned nanocrystals and a shell surrounding the core.

[0077] The shell of the quantum dot may serve as a protective layer for maintaining semiconductor properties by preventing chemical deterioration of the core and / or a charging layer for imparting electrophoretic properties to the quantum dot.

[0078] The shell may be a single layer or multiple layers.

[0079] The interface between the core and the shell may have a concentration gradient, where the concentration of the elements present in the shell decreases towards the center.

[0080] Examples of the shell of the quantum dot include metal oxides or non-metal oxides, semiconductor compounds, or combinations thereof.

[0081] For example, the metal oxide or non-metal oxide can be SiO2, Al2O3, TiO2, ZnO, MnO, Mn2O3, Mn3O4, CuO, FeO, Fe2O3, Fe3O4, CoO, Co3O4, NiO, or the metal oxide or non-metal oxide can be a binary compound such as, for example, MgAl2O4, CoFe2O4, or NiFe2O4, CoMn2O4, etc., but the embodiments supported by the present disclosure are not limited thereto.

[0082] In some aspects, examples of semiconductor compounds include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, etc. However, the embodiments supported by the present disclosure are not limited thereto.

[0083] The interface between the core and the shell can have a concentration gradient, where the concentration of the elements present in the shell decreases towards the center.

[0084] In some aspects, the semiconductor nanocrystal can have a structure including a semiconductor nanocrystal core and a multi-layer shell surrounding the semiconductor nanocrystal core.

[0085] In an embodiment, the multi-layer shell can have two or more than two layers, such as, for example, two, three, four, five or more than five layers.

[0086] Two adjacent layers of the shell can have a single composition or different compositions.

[0087] Each layer in the multi-layer shell can have a composition that varies along the radius.

[0088] The quantum dots according to the exemplary aspects of the present disclosure can have a full width at half maximum (FWHM) of the emission wavelength spectrum of about 45 nm or less than 45 nm, preferably about 40 nm or less than 40 nm, more preferably about 30 nm or less than 30 nm, and can improve the color purity or color reproducibility in these exemplary ranges.

[0089] In some aspects, since the light emitted by the quantum dots is emitted in all directions, the wide viewing angle can be improved.

[0090] In the quantum dots, the shell material and the core material can have different band gaps.

[0091] For example, the band gap of the shell material can be greater than the band gap of the core material.

[0092] In other embodiments, the band gap of the shell material can be less than the band gap of the core material.

[0093] The quantum dots can have multiple layers of shells.

[0094] In the multiple-layer shell, the band gap of the outer layer can be greater than the band gap of the inner layer (i.e., the layer closer to the core).

[0095] In the multiple-layer shell, the band gap of the outer layer can be less than the band gap of the inner layer.

[0096] The quantum dots can control the absorption / emission wavelength by adjusting the composition and size.

[0097] The maximum emission peak wavelength of the quantum dots can have a wavelength range from ultraviolet to infrared or higher than infrared wavelength.

[0098] The quantum dots can have a quantum efficiency of about 10% or greater than 10%, for example, about 30% or greater than 30%, about 50% or greater than 50%, about 60% or greater than 60%, about 70% or greater than 70%, about 90% or greater than 90%, or even 100%.

[0099] The quantum dots can have a relatively narrow spectrum.

[0100] The quantum dots can have a full width at half maximum of the emission wavelength spectrum of, for example, about 50 nm or less than 50 nm, such as about 45 nm or less than 45 nm, about 40 nm or less than 40 nm, or about 30 nm or less than 30 nm.

[0101] The quantum dots can have a particle size of about 1 nm or greater than 1 nm and about 100 nm or less than 100 nm.

[0102] The size of the particle refers to the diameter of the particle, or the diameter converted from a two-dimensional image obtained by transmission electron microscope analysis assuming a spherical shape.

[0103] The quantum dots can have a thickness of about 1 nm to about 20 nm, such as 2 nm or greater than 2 nm, 3 nm or greater than 3 nm, or 4 nm or greater than 4 nm and 50 nm or less than 50 nm, 40 nm or less than 40 nm, 30 nm or less than 30 nm, 20 nm or less than 20 nm, 15 nm or less than 15 nm, for example, 10 nm or less than 10 nm.

[0104] The shape of the quantum dots is not particularly limited to the examples described herein.

[0105] For example, the shape of the quantum dots can include, but is not limited to, spheres, polyhedra, pyramids, multi-legged shapes, cubes, cuboids, nanotubes, nanorods, nanowires, nanosheets, or combinations thereof.

[0106] The quantum dots are commercially available or can be suitably synthesized.

[0107] The particle size of the quantum dots can be relatively freely controlled, and the particle size can be uniformly controlled during the colloidal synthesis process.

[0108] According to an embodiment, the quantum dot complex QDC can include a ligand LD bound to the surface of the quantum dot QD.

[0109] According to an embodiment, the ligand LD can include a first ligand LD1 and a second ligand LD2.

[0110] Each of the first ligand LD1 and the second ligand LD2 can be bound to a different coupling part ST provided on the surface of the quantum dot QD.

[0111] In an embodiment, the shell SL of the quantum dot QD can include a plurality of coupling parts ST.

[0112] The plurality of coupling parts ST includes a first coupling part ST1, a second coupling part ST2, and a third coupling part ST3. In some embodiments, the first ligand LD1 is bound to the first coupling part ST1, and the second ligand LD2 can be bound to the second coupling part ST2 or the third coupling part ST3.

[0113] Figures 3 to 5 Schematically shows the formation in which the ligand LD is bound to the surface of the quantum dot QD in the quantum dot complex QDC.

[0114] Figure 3 is Figure 2 an enlarged view of part A of Figure 4 is Figure 2 an enlarged view of part B of Figure 5 is Figure 2 an enlarged view of part C of

[0115] Reference Figures 3 to 5 shows that the plurality of coupling parts ST provided on the surface of the shell SL of the quantum dot QD can be defect parts exposed on the surface of the semiconductor nanocrystals contained in the shell SL.

[0116] Different from the atoms existing in a completely crystalline state inside the shell SL, the plurality of coupling parts ST can have dangling bonds that are coordinatively unsaturated on the surface of the shell SL.

[0117] In an embodiment, the shell SL includes II-VI group compounds, III-V group compounds, IV-VI group compounds, etc., and the shell SL includes group II elements, group III elements, group IV elements, and group V elements. In an embodiment, each group VI element can be exposed in a coordination unsaturated state, or bound to a corresponding element but exposed in a coordination unsaturated state to provide a plurality of binding sites ST.

[0118] The plurality of linking portions ST included in the shell SL may include a first linking portion ST1 exposed to positive ions, a second linking portion ST2 exposed to negative ions, and defects such as vacancies. For example, the vacancies may include a third linking portion ST3.

[0119] Reference Figure 3 , the first ligand LD1 binds to the first linking portion ST1, and the first linking portion ST1 may be a defective portion where a cation is exposed.

[0120] In Figure 3 , it is illustrated that the shell SL contains ZnS, and the first linking portion ST1 is a Zn cation.

[0121] However, the embodiments of the present disclosure are not limited thereto, and the first linking portion ST1 may be at least one selected from Zn cations, Cd cations, Hg cations, Mg cations, Ag cations, Cu cations, Ga cations, Al cations, In cations, Sn cations, and Pb cations.

[0122] For example, the first ligand LD1 may include an electron-donating functional group to bind to the first linking portion ST1 that is a defective portion where a cation is exposed.

[0123] The first ligand LD1 may be a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted mercapto group, a substituted or unsubstituted oxy group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms.

[0124] The first ligand LD1 may include a substituted or unsubstituted ethyl group, a substituted or unsubstituted octyl group, a substituted or unsubstituted dodecyl group, or a substituted or unsubstituted phenyl group.

[0125] The first ligand LD1 according to the embodiment may be oleic acid.

[0126] The term "substituted or unsubstituted" in this specification means a deuterium atom, a halogen atom, a cyano group, a nitro group, an amino group, a silyl group, an oxy group, a thio group, a sulfinyl group, a sulfonyl group, a carbonyl group, a boron group, a phosphine oxide group, a phosphine sulfide group, an alkyl group, an alkenyl group, an alkoxy group, a hydrocarbon ring group, an aryl group, and a heterocyclic group.

[0127] In some aspects, each of the exemplary substituents described herein can be substituted or unsubstituted.

[0128] For example, a biphenyl group can be interpreted as an aryl group or a phenyl group substituted with a phenyl group.

[0129] Reference Figure 4 , the second ligand LD2 binds to the second linking portion ST2, and the second linking portion ST2 can be a defective portion where a negative ion is exposed.

[0130] Figure 4 An example is illustrated in which the shell SL contains ZnS and the second linking portion ST2 is an S anion.

[0131] However, the embodiments of the present disclosure are not limited thereto, and the second linking portion ST2 can be at least one selected from S anions, Se anions, Te anions, N anions, P anions, As anions, and Sb anions.

[0132] The second ligand LD2 can contain, for example, a halogen element and can contain at least one of, for example, fluorine, chlorine, bromine, and iodine.

[0133] The energy band position of the quantum dot complex QDC can be adjusted according to the type of halogen element.

[0134] The halogen element can control the dipoles on the surface of the quantum dot complex and thus adjust the energy band position of the quantum dot complex.

[0135] Generally, when a halogen element is introduced, the energy band position moves in the negative direction, and the degree of movement can be controlled by the electron affinity of the halogen atom and the amount introduced into the quantum dot complex.

[0136] Reference Figure 5 , the second ligand LD2 can bind to the third linking portion ST3. According to one or more embodiments of the present disclosure, the second ligand LD2 can bind to the third linking portion ST3 and bind to the second linking portion ST2.

[0137] The third linking portion ST3 can be a defect, for example, a defect exposed in a state where a vacancy or a cation and an anion are combined.

[0138] The third coupling part ST3 may be a defect, for example, in the case of a vacancy. Alternatively or additionally, the third coupling part ST3 may be a defective part in which cations and anions contained in the shell SL combine to form a crystal, but some of the bonds are broken due to coordination unsaturation.

[0139] The quantum dot complex QDC according to an embodiment may include a halogen element through the second ligand LD2.

[0140] Based on the total content of the quantum dot complex QDC, the quantum dot complex QDC may include 1 at% to 12 at% of halide.

[0141] For example, relative to the total content of the quantum dot complex, the quantum dot complex QDC may include chlorine Cl in an amount of 5 at% to 7 at%, or may include bromine Br in an amount of 2 at% to 4 at%, iodine I in an amount of 1 at% to 2 at%, or fluorine F in an amount of 9 at% to 12 at%.

[0142] The quantum dot complex QDC according to an embodiment may include an organic material through the first ligand LD1.

[0143] For example, based on the total content of the quantum dot complex, the quantum dot complex QDC may include an organic material in an amount of 10 at% or more than 10 at%.

[0144] Since the quantum dot complex QDC according to an embodiment includes a sufficient amount of the first ligand LD1, the quantum dot complex QDC may have appropriate solubility.

[0145] The quantum dot complex QDC according to an embodiment may control the color of the emitted light according to the particle size of the quantum dots QD, and thus, the quantum dots QD may have various emission colors, for example, in the case of blue, red, and green.

[0146] Because the particle size of the quantum dots QD is small, the quantum dot complex QDC may support the emission of light in a shorter wavelength region.

[0147] For example, among the quantum dots QD having the same core, the particle size of the quantum dots emitting green light may be smaller than the particle size of the quantum dots emitting red light.

[0148] In some aspects, among the quantum dots QD having the same core, the particle size of the quantum dots emitting blue light may be smaller than the particle size of the quantum dots emitting green light.

[0149] However, the embodiments supported by the present disclosure are not limited thereto, and even among the quantum dots QD having the same core, the particle size may be adjusted according to the material for forming the shell, the shell thickness, etc.

[0150] In some aspects, when the quantum dots QD have various emission colors (e.g., taking blue, red, and green as examples), the quantum dots QD with different emission colors can have different core materials.

[0151] In an embodiment, for a quantum dot complex QDC capable of emitting red light, the valence band of the quantum dot complex QDC can be from about -5.60 eV to -5.80 eV.

[0152] In an embodiment, for a quantum dot complex QDC capable of emitting green light, the valence band of the quantum dot complex QDC can be from about -5.73 eV to -5.93 eV.

[0153] In an embodiment, for a quantum dot complex QDC capable of emitting blue light, the valence band of the quantum dot complex QDC can be from about -5.78 eV to -5.98 eV.

[0154] The quantum dot complex according to the embodiment includes a first ligand and a second ligand stably bound to the surface of the quantum dot, and the binding of the ligand to the surface of the quantum dot can support a quantum dot complex with improved light efficiency.

[0155] Hereinafter, reference will be made to Figure 6 and Figure 7 to describe a quantum dot complex according to another embodiment.

[0156] Figure 6 is a cross-sectional view of a quantum dot complex according to another embodiment, and Figure 7 is an enlarged cross-sectional view of a part of a quantum dot complex according to another embodiment.

[0157] The description of components identical to those described herein will be omitted.

[0158] Reference Figure 6 , the quantum dot complex QDC according to the embodiment can include a quantum dot QD and a ligand LD bound to the surface of the quantum dot QD.

[0159] The quantum dot complex QDC includes a ligand LD containing a functional group. In an embodiment, the ligand LD is attached to the surface of the quantum dot QD, and the surface of the quantum dot QD can have modified surface properties.

[0160] The quantum dot complex QDC can be referred to as a surface-modified quantum dot.

[0161] The quantum dot QD can include a core CR and a shell SL surrounding the core CR.

[0162] However, embodiments supported by the present disclosure are not limited thereto, and the quantum dot QD may have a single-layer structure or multiple shells.

[0163] The quantum dot complex QDC according to an embodiment may include a ligand LD bound to the surface of the quantum dot QD.

[0164] The ligand LD according to an embodiment may include a first ligand LD1, a second ligand LD2, and a third ligand LD3.

[0165] Each of the first ligand LD1, the second ligand LD2, and the third ligand LD3 may be bound to a different coupling part ST provided on the surface of the quantum dot QD.

[0166] In an embodiment, the shell SL of the quantum dot QD may provide or include multiple coupling parts ST.

[0167] The multiple coupling parts ST include a first coupling part ST1, a second coupling part ST2, and a third coupling part ST3, and the first ligand LD1 is attached to the first coupling part ST1. The second ligand LD2 may be bound to the second coupling part ST2 or the third coupling part ST3, and the third ligand LD3 may be bound to the second coupling part ST2 or the third coupling part ST3.

[0168] Figure 7 is Figure 6 an enlarged view of part D.

[0169] The third ligand LD3 according to an embodiment may be any one selected from phosphine, phosphine oxide, imidazole, and pyridine that is bound to the surface of the quantum dot QD.

[0170] In some aspects, the third ligand LD3 may be a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted mercapto group, or a substituted or unsubstituted oxy group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms.

[0171] The quantum dot complex QDC according to an embodiment may include a halogen element through the second ligand LD2.

[0172] For example, with respect to the total content of the quantum dot complex QDC, the quantum dot complex QDC may include chlorine Cl in an amount of 5 at% to 7 at%, or may include bromine Br in an amount of 2 at% to 4 at%, iodine I in an amount of 1 at% to 2 at%, or fluorine F in an amount of 9 at% to 12 at%.

[0173] The quantum dot complex QDC according to the embodiment may include an organic material through a first ligand LD1 and a third ligand LD3.

[0174] For example, with respect to the total content of the quantum dot complex, the quantum dot complex QDC may include 10 at% or more than 10 at% of the organic material.

[0175] In some aspects, since the quantum dot complex QDC according to the embodiment includes a sufficient amount of the first ligand LD1 and the third ligand LD3, the quantum dot complex QDC may have an appropriate solubility.

[0176] The quantum dot complex QDC according to the embodiment may control the color of the emitted light according to the particle size of the quantum dot QD, and thus, the quantum dot QD may have various emission colors, for example, taking blue, red, and green as examples.

[0177] Because the particle size of the quantum dot QD is small, the quantum dot complex QDC may support the emission of light in a shorter wavelength region.

[0178] For example, among quantum dots QD having the same core, the particle size of the quantum dot emitting green light may be smaller than that of the quantum dot emitting red light.

[0179] In some aspects, among quantum dots QD having the same core, the particle size of the quantum dot emitting blue light may be smaller than that of the quantum dot emitting green light.

[0180] However, the embodiments supported by the present disclosure are not limited thereto, and even among quantum dots QD having the same core, the particle size may be adjusted according to the material for forming the shell, the shell thickness, etc.

[0181] In some aspects, when the quantum dot QD has various emission colors (for example, taking blue, red, and green as examples), the quantum dots QD having different emission colors may have different core materials.

[0182] In the embodiment, for the quantum dot complex QDC capable of emitting red light, the valence band of the quantum dot complex QDC may be about -5.60 eV to -5.80 eV.

[0183] In the embodiment, for the quantum dot complex QDC capable of emitting green light, the valence band of the quantum dot complex QDC may be about -5.73 eV to -5.93 eV.

[0184] In the embodiment, for the quantum dot complex QDC capable of emitting blue light, the valence band of the quantum dot complex QDC may be about -5.78 eV to -5.98 eV.

[0185] The quantum dot complex according to an embodiment includes a first ligand, a second ligand, and a third ligand stably bound to the surface of a quantum dot, and the binding of the ligands to the surface of the quantum dot can support a quantum dot complex with improved light efficiency.

[0186] Hereinafter, reference will be made to Figure 8 and Figure 9 to describe a display device according to an embodiment.

[0187] Figure 8 is a schematic cross-sectional view of a light-emitting device according to an embodiment, and Figure 9 is a schematic cross-sectional view of a display device according to an embodiment.

[0188] First, referring to Figure 8 , a display device according to an embodiment may include a light-emitting element ED.

[0189] The light-emitting element ED includes a first electrode E1, a light-emitting layer EML, and a second electrode EL2.

[0190] The first electrode E1 is also referred to as an anode electrode and may be composed of a single layer including a transparent conductive oxide layer or a metal material, or a multi-layer including a transparent conductive oxide layer or a metal material.

[0191] The transparent conductive oxide layer may include indium tin oxide ITO, poly-ITO, indium zinc oxide IZO, indium gallium zinc oxide IGZO, and indium tin zinc oxide ITZO.

[0192] The metal material may include silver Ag, molybdenum Mo, copper Cu, gold Au, and aluminum Al.

[0193] The first electrode E1 may be electrically connected to a pixel circuit unit PC located below the first electrode E1.

[0194] The pixel circuit unit PC may include a transistor, and the first electrode E1 may receive an output current to be transmitted from the pixel circuit unit PC to the light-emitting layer EML.

[0195] A pixel defining layer PDL may be located on the first electrode E1.

[0196] The pixel defining layer PDL includes an opening overlapping at least a part of the first electrode E1.

[0197] The pixel defining layer PDL may define the formation position of the light-emitting layer EML such that the light-emitting layer EML may be located on an exposed portion of the upper surface of the first electrode E1.

[0198] The light-emitting layer EML may be located within a pixel opening defined by the pixel defining layer PDL.

[0199] The light-emitting layer EML according to an embodiment may include the quantum dot complexes described herein.

[0200] Although the light-emitting layer EML is shown as a single layer in Figure 8 it, auxiliary layers (e.g., exemplified by an electron injection layer, an electron transport layer, a hole transport layer, and a hole injection layer) may also be included above and / or below the light-emitting layer EML. The hole injection layer and the hole transport layer may be located below the light-emitting layer EML, and the electron transport layer and the electron injection layer may be located above the light-emitting layer EML.

[0201] The second electrode E2 may be located on the pixel defining layer PDL and the light-emitting layer EML.

[0202] The second electrode E2 is also referred to as a cathode electrode and is formed of a transparent conductive layer including indium tin oxide ITO, indium zinc oxide IZO, indium gallium zinc oxide IGZO, and indium tin zinc oxide ITZO.

[0203] In some aspects, the second electrode E2 may have a semi-transparent property, and in this case, a microcavity may be formed together with the first electrode E1.

[0204] According to the microcavity structure, due to the interval and characteristics between the two electrodes, light of a specific wavelength is emitted upward, and thus, red, green, or blue light can be displayed.

[0205] Referring to Figure 9 , the display device according to an embodiment includes a pixel circuit unit PC, a light-emitting element ED connected to the pixel circuit unit PC, and a color conversion unit CCL located on the light-emitting element ED.

[0206] For the sake of brevity, repeated descriptions of the same elements described herein are omitted.

[0207] The light-emitting layer EML according to an embodiment may include organic materials that emit red light, green light, and blue light.

[0208] The light-emitting layer EML that emits red light, green light, and blue light may include low-molecular or high-molecular organic materials.

[0209] Although Figure 9 the example of shows the light-emitting layer EML as a single layer, auxiliary layers (e.g., exemplified by an electron injection layer, an electron transport layer, a hole transport layer, and a hole injection layer) may be included above and / or below the light-emitting layer EML, the hole injection layer and the hole transport layer may be located below the light-emitting layer EML, and the electron transport layer and the electron injection layer may be located above the light-emitting layer EML.

[0210] The encapsulation layer ENC may be located on the second electrode E2.

[0211] The encapsulation layer ENC may include at least one inorganic layer and at least one organic layer.

[0212] The display device according to an embodiment may include a color conversion layer CCL overlapping with the light-emitting element ED.

[0213] The color conversion layer CCL may include the quantum dot complex described above.

[0214] For example, the color conversion layer CCL located in the red light-emitting region may include a red quantum dot complex, and the color conversion layer CCL located in the green light-emitting region may include a green quantum dot complex.

[0215] The partition wall BM may be located between adjacent color conversion layers CCL, contain a black material capable of blocking light, and may prevent color mixing between adjacent light-emitting regions.

[0216] The display device including the quantum dot complex described above may provide improved luminous efficiency.

[0217] Hereinafter, reference will be made to Figure 10 and Figure 11 to describe a method for manufacturing a quantum dot complex according to an embodiment.

[0218] Figure 10 is a flowchart illustrating a manufacturing process of a quantum dot complex according to an embodiment, and Figure 11 is a schematic diagram of a quantum dot complex according to the manufacturing process of Figure 10 .

[0219] Referring to Figure 10 , the quantum dot complex according to an embodiment is formed through the following steps: forming a quantum dot complex to which a first ligand LD1 is bound (at S1), and mixing and purifying the quantum dot complex with a first solution containing a second ligand (at S2).

[0220] Referring to Figure 10 and Figure 11 , the quantum dot complex QDC may be provided in the form of quantum dots QD, and the quantum dots QD include a first ligand LD1 on the surface of the quantum dot complex QD.

[0221] In some aspects, most of the first ligands LD1 may be provided in the form combined with the first coupling part ST1 (for example, at S1).

[0222] In some aspects, the manufacturing process includes mixing the quantum dot complex QDC containing the first ligand LD1 with a first solution containing MX to be purified (for example, at S2).

[0223] By mixing as referred to in Figure 10 andFigure 11 The described quantum dot complex QDC is mixed with a first solution. The quantum dot complex QDC can include a second ligand LD2 bound to a second linker ST2, and a purification process can be carried out simultaneously.

[0224] In some aspects, the purification process can remove unnecessary by-products and additional ligands.

[0225] In an example, in MX, M can be any one of Na, Mg, K, Ca, Zn, In, Ga, Sn, and Sb, and X can be any one of F, Cl, Br, and I.

[0226] MX can be provided in a polar solvent at a concentration of 0.1 M to 0.5 M.

[0227] The polar solvent can include, for example, methanol, ethanol, phenol, hydroquinone, ethylene glycol, glycerol, diethylene glycol, triethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, or any combination thereof, but is not limited thereto.

[0228] By referring to Figure 10 and Figure 11 the described manufacturing process, the quantum dot complex QDC described in Figures 1 to 5 can be obtained.

[0229] By referring to Figure 10 and Figure 11 The quantum dot complex QDC prepared by the described manufacturing method can include a halogen element through the second ligand LD2.

[0230] For example, based on the total content of the quantum dot complex QDC, the quantum dot complex QDC can include chlorine Cl in an amount of 5 at% to 7 at%, bromine Br in an amount of 2 at% to 4 at%, iodine I in an amount of 1 at% to 2 at%, or fluorine F in an amount of 9 at% to 12 at%.

[0231] By referring to Figure 10 and Figure 11 The quantum dot complex QDC prepared by the described manufacturing method can include an organic material through the first ligand LD1.

[0232] For example, relative to the total content of the quantum dot complex, the quantum dot complex QDC can include an organic material in an amount of 10 at% or more than 10 at%.

[0233] Since the quantum dot complex QDC according to the embodiment includes a sufficient amount of the first ligand LD1, the quantum dot complex QDC can have appropriate solubility.

[0234] In an embodiment, for reference to Figure 10 andFigure 11 A quantum dot complex QDC that is manufactured by the manufacturing method described herein and is capable of emitting red light, and the quantum dot complex QDC may have a valence band of about -5.70 eV.

[0235] In an embodiment, for a quantum dot complex QDC that is manufactured by the manufacturing method described herein with reference to Figure 10 and Figure 11 and is capable of emitting green light, the valence band of the quantum dot complex QDC may be about -5.83 eV.

[0236] In an embodiment, for a quantum dot complex QDC that is manufactured by the manufacturing method described herein with reference to Figure 10 and Figure 11 and is capable of emitting blue light, the valence band of the quantum dot complex QDC may be about -5.88 eV.

[0237] In some alternative embodiments, when a surface treatment process is carried out to include a second ligand LD2, the valence band of the quantum dot complex QDC emitting red light may be about -5.20 eV to -5.33 eV, the valence band of the quantum dot complex QDC emitting green light may be about -5.35 eV to -5.48 eV, and the valence band of the quantum dot complex QDC emitting blue light may be about -6.25 eV to -6.36 eV.

[0238] According to the manufacturing method of the embodiment, the valence band of the quantum dot complex QDC emitting red light may be negatively shifted by about 0.37 eV to 0.50 eV, the valence band of the quantum dot complex QDC emitting green light may be negatively shifted by about 0.35 eV to 0.48 eV, and the valence band of the quantum dot complex QDC emitting blue light may be negatively shifted by about 0.37 eV to 0.48 eV.

[0239] In another example, after forming a quantum dot complex containing a first ligand, a surface treatment may be carried out at a high temperature such that the quantum dot complex includes a second ligand LD2, and then a purification process may be carried out.

[0240] According to this method, there may be a problem that the first ligand LD1 may be removed during the surface treatment of the second ligand LD2, and the efficiency of the quantum dot complex QDC may be reduced.

[0241] However, according to the embodiment, the surface treatment of the quantum dot complex to include the second ligand LD2 may be carried out during the purification process that can be carried out at room temperature, which can prevent the removal of the first ligand LD1.

[0242] Thus, for example, the manufacturing process described herein for combining the second ligand LD2 can be simplified, and the first ligand LD1 and the second ligand LD1 can stably bind to the quantum dot complex QDC, thereby providing a quantum dot complex QDC with improved efficiency.

[0243] In the following, reference will be made to Figure 12 and Figure 13 to describe a method for manufacturing a quantum dot complex according to another embodiment.

[0244] Figure 12 is a flowchart of the manufacturing process of a quantum dot complex according to an embodiment, and Figure 13 is a schematic diagram of a quantum dot complex according to the manufacturing process of Figure 12 .

[0245] Referring to Figure 12 , the method for manufacturing a quantum dot complex according to an embodiment can be manufactured by the following: a step S1 of providing a quantum dot complex combined with a first ligand LD1; a step S2 of surface treatment to combine a third ligand LD3 with the quantum dot complex; and a step S3 of purification by mixing the quantum dot complex in a first solution containing a second ligand.

[0246] Compared with the exemplary manufacturing process described with reference to Figure 10 , the manufacturing process described with reference to Figure 12 can further include a surface treatment step S2, which binds the third ligand LD3 to the quantum dot complex QDC.

[0247] Referring to Figure 12 and Figure 13 , the quantum dot complex QDC can be provided in the form of quantum dots QD, and the quantum dots QD include a first ligand LD1 on the surface of the quantum dots QD.

[0248] In some aspects, most of the first ligand LD1 can be provided in the form combined with the first linker ST1 (e.g., at S1).

[0249] In some aspects, the manufacturing method includes mixing the quantum dot complex QDC with a solution containing a third ligand LD3 and an organic solvent, and QDC reacts at room temperature for about 30 minutes.

[0250] The organic solvent can include hexane, toluene, chloroform, dimethyl sulfoxide, or dimethylformamide.

[0251] However, the embodiments supported by the present disclosure are not limited thereto.

[0252] The third ligand LD3 can include any one selected from phosphine, phosphine oxide, imidazole, and pyridine that binds to the surface of the quantum dots QD.

[0253] In some aspects, the third ligand LD3 can be a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted mercapto group, or a substituted or unsubstituted oxy group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms.

[0254] The quantum dot complex QDC subjected to this surface treatment process can have a form containing the first ligand LD1 and the third ligand LD3.

[0255] In an example, a quantum dot complex QDC containing the first ligand LD1 and the third ligand LD3 can be provided to be dispersed in a first solution containing MX.

[0256] By providing a quantum dot complex QDC containing the first ligand LD1 and the third ligand LD3 to be dispersed in a first solution containing MX, a purification process can be carried out while obtaining a quantum dot complex QDC containing the second ligand LD2.

[0257] In some aspects, the purification process can remove unnecessary by-products and additional ligands.

[0258] In MX, M can be any one of Na, Mg, K, Ca, Zn, In, Ga, Sn, and Sb, and X can be any one of F, Cl, Br, and I.

[0259] MX can be provided in a polar solvent at a concentration of 0.1 M to 0.5 M.

[0260] The polar solvent can include, for example, methanol, ethanol, phenol, benzenediol, ethylene glycol, glycerol, diethylene glycol, triethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, or any combination thereof, but is not limited thereto.

[0261] By reference Figure 12 and Figure 13 the described manufacturing process, the Figures 6 to 7 quantum dot complex QDC described therein can be obtained.

[0262] The quantum dot complex QDC prepared by the described manufacturing method can contain a halogen element by the second ligand LD2.

[0263] For example, relative to the total content of the quantum dot complex, the quantum dot complex QDC can contain chlorine Cl in an amount of 5 at% to 7 at%, bromine Br in an amount of 2 at% to 4 at%, iodine I in an amount of 1 at% to 2 at%, or fluorine F in an amount of 9 at% to 12 at%.

[0264] prepared by referring to Figure 12 and Figure 13 The quantum dot complex QDC prepared by the manufacturing method described can include an organic material through a first ligand LD1 and a third ligand LD3.

[0265] For example, relative to the total content of the quantum dot complex QDC, the quantum dot complex QDC can include an organic material included in an amount of 10 at% or greater than 10 at%.

[0266] Since the quantum dot complex QDC according to the embodiment includes sufficient amounts of the first ligand LD1 and the third ligand LD3, the quantum dot complex QDC can have appropriate solubility.

[0267] In an embodiment, for the quantum dot complex QDC that is manufactured by the manufacturing method described herein by referring to Figure 12 and Figure 13 and is capable of emitting red light, the quantum dot complex QDC can have a valence band of about -5.70 eV.

[0268] In an embodiment, for the quantum dot complex QDC that is manufactured by the manufacturing method described herein by referring to Figure 12 and Figure 13 and is capable of emitting green light, the valence band of the quantum dot complex QDC can be about -5.83 eV.

[0269] In an embodiment, for the quantum dot complex QDC that is manufactured by the manufacturing method described herein by referring to Figure 12 and Figure 13 and is capable of emitting blue light, the valence band of the quantum dot complex QDC can be about -5.88 eV.

[0270] In some alternative embodiments, when a separate surface treatment process is performed to include a second ligand LD2, the valence band of the quantum dot complex QDC emitting red light can be about -5.20 eV to -5.33 eV, the valence band of the quantum dot complex QDC emitting green light can be about -5.35 eV to -5.48 eV, and the valence band of the quantum dot complex QDC emitting blue light can be about -6.25 eV to -6.36 eV.

[0271] According to the manufacturing method of the embodiment, the valence band of the quantum dot complex QDC emitting red light can be negatively shifted by about 0.37 eV to 0.50 eV, the valence band of the quantum dot complex QDC emitting green light can be negatively shifted by about 0.35 eV to 0.48 eV, and the valence band of the quantum dot complex QDC emitting blue light can be negatively shifted by about 0.37 eV to 0.48 eV.

[0272] In another example, after forming a quantum dot complex containing a first ligand, a surface treatment can be carried out at a high temperature such that the quantum dot complex contains a second ligand LD2 and a third ligand LD3, and then a purification process can be carried out.

[0273] According to this method, a problem may occur during the surface treatment of the second ligand LD2 and the third ligand LD3 in which the first ligand LD1 is removed, and thus the efficiency of the quantum dot complex QDC may be reduced.

[0274] However, according to an embodiment, the surface treatment of the quantum dot complex can be carried out during a purification process that can be carried out at room temperature to contain the second ligand LD2.

[0275] Accordingly, the manufacturing process of binding the second ligand can be simplified, and the first ligand LD1, the second ligand LD2, and the third ligand LD3 can be stably bound to the quantum dot complex QDC, thereby providing a quantum dot complex QDC with improved efficiency.

[0276] Hereinafter, Comparative Example 1, Comparative Example 2, Embodiment 1, and Embodiment 2 will be described with reference to Table 1.

[0277] Comparative Example 1 is a quantum dot complex in which blue quantum dots in the form of ZnTeSe / ZnSe / ZnS are purified using ethanol, and Comparative Example 2 is a quantum dot complex in which blue quantum dots in the form of ZnTeSe / ZnSe / ZnS are surface-treated with ZnCl2 and then purified using ethanol. Embodiment 1 is a quantum dot complex obtained by purifying blue quantum dots in the form of ZnTeSe / ZnSe / ZnS using ethanol containing ZnCl2, and Embodiment 2 is a quantum dot complex of blue quantum dots in the form of ZnTeSe / ZnSe / ZnS purified using ethanol containing ZnI2.

[0278] Table 1

[0279] Referring to Table 1, in the case of Embodiment 1 and Embodiment 2, it was confirmed that the light efficiency was significantly improved to 71% and 82% respectively compared to Comparative Example 1 (38%) and Comparative Example 2 (45%).

[0280] In the case of Embodiment 1 and Embodiment 2, it was confirmed that the valence band value shifted negatively compared to Comparative Example 1 and Comparative Example 2.

[0281] In some aspects, the negative shift is caused by an increase in the amount of the surface-treated second ligand.

[0282] According to the valence band value of the negative shift, the band offset between the quantum dots and the electron transport layer can be reduced, and the device efficiency can be improved by improving the electron injection.

[0283] In some aspects, compared with Comparative Example 2, Embodiment 1 and Embodiment 2 may contain 10 at% or more than 10 at% of the organic ligand.

[0284] Thus, for example, when the organic ligand is stably bound to the surface of the quantum dots and an ink containing the quantum dot complex is prepared, the jetting stability can be improved by controlling the precipitation of the organic material.

[0285] Conversely, in another exemplary embodiment, when the purification process is performed with ethanol containing ZnCl2 according to the manufacturing process of the embodiment, it was confirmed that Cl contained in the quantum dot complex was contained at 6.89 at%.

[0286] In some aspects, when the purification process is performed with ethanol containing ZnBr2 according to the manufacturing process of the embodiment, it was confirmed that Br contained in the quantum dot complex was contained at about 2.96 at%.

[0287] In some aspects, when the purification process is performed with ethanol containing ZnI2 according to the manufacturing process of the embodiment, it was confirmed that I contained in the quantum dot complex was contained at about 1.86 at%.

[0288] It has been confirmed that the quantum dot complex prepared by the manufacturing process according to the embodiment can provide a plurality of ligands stably bound to the coupling portion, thereby providing quantum dots with improved luminescence efficiency.

[0289] Although embodiments supported by aspects of the present disclosure have been described in detail herein, the scope of the embodiments supported by the present disclosure is not limited thereto, and various modifications and improvements by those skilled in the art using the concepts defined in the following claims are also included in the scope of the present disclosure.

Claims

1. A quantum dot complex, comprising: a quantum dot; and a ligand bound to the surface of the quantum dot, wherein a plurality of linking portions are provided on the surface of the quantum dot, and the ligand is bound to the plurality of linking portions, wherein the plurality of linking portions include a first linking portion and a second linking portion, wherein the ligand includes: a first ligand bound to the first linking portion, and a second ligand bound to the second linking portion, wherein: the second ligand contains a halogen element, and the halogen element is included in an amount of 1 at% to 12 at% relative to the total content of the quantum dot complex.

2. The quantum dot complex according to claim 1, wherein: the halogen element is one of the following: chlorine, which is included in an amount of 5 at% to 7 at% relative to the total content of the quantum dot complex, bromine, which is included in an amount of 2 at% to 4 at% relative to the total content of the quantum dot complex, iodine, which is included in an amount of 1 at% to 2 at% relative to the total content of the quantum dot complex, and fluorine, which is included in an amount of 9 at% to 12 at% relative to the total content of the quantum dot complex.

3. The quantum dot complex according to claim 1, wherein: the quantum dot complex has an organic content of 10 at% or greater than 10 at% relative to the total content of the quantum dot complex.

4. The quantum dot complex according to claim 1, wherein: the quantum dot complex emits red light, and the valence band value of the quantum dot complex is -5.60 eV to -5.80 eV.

5. The quantum dot complex according to claim 1, wherein: the quantum dot complex emits green light, and the valence band value of the quantum dot complex is -5.73 eV to -5.93 eV.

6. The quantum dot complex according to claim 1, wherein: the quantum dot complex emits blue light, and the valence band value of the quantum dot complex is -5.78 eV to -5.98 eV.

7. The quantum dot complex according to claim 1, wherein: the plurality of linking portions further includes a third linking portion, and the ligand further includes a third ligand bound to the second linking portion or the third linking portion.

8. The quantum dot complex according to claim 7, wherein: the third ligand is any one selected from phosphine and phosphine oxide.

9. The quantum dot complex according to claim 8, wherein: the third ligand further includes a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, a substituted or unsubstituted alkenyl group having 2 to 30 carbon atoms, a substituted or unsubstituted mercapto group, a substituted or unsubstituted oxy group, a substituted or unsubstituted aryl group having 6 to 30 ring carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring carbon atoms.

10. The quantum dot complex according to claim 1, wherein: the quantum dot includes a core and a shell surrounding the core.

11. The quantum dot complex according to claim 10, wherein: The plurality of linking portions are provided on the surface of the shell.

12. The quantum dot complex according to claim 10, wherein: The core includes a first semiconductor nanocrystal, The shell includes a second semiconductor nanocrystal different from the first semiconductor nanocrystal, and Each of the first semiconductor nanocrystal and the second semiconductor nanocrystal is selected from II-VI group compounds, III-V group compounds, IV-VI group compounds, group IV elements, group IV compounds, and combinations thereof.

13. A display device, comprising: A first electrode; A light-emitting layer located on the first electrode, and A second electrode located on the light-emitting layer, the light-emitting layer containing a quantum dot complex, Wherein the quantum dot complex comprises: Quantum dots; and A ligand bound to the surface of the quantum dots, Wherein a plurality of linking portions are provided on the surface of the quantum dots, and the ligand is bound to the plurality of linking portions, Wherein the plurality of linking portions include a first linking portion and a second linking portion, Wherein the ligand comprises: A first ligand bound to the first linking portion, and A second ligand bound to the second linking portion; Wherein: The second ligand contains a halogen element, and Relative to the total content of the quantum dot complex, the halogen element is contained in an amount of 1 at% to 12 at%.

14. The display device according to claim 13, wherein: The halogen element is one of the following: Chlorine, wherein relative to the total content of the quantum dot complex, the chlorine is contained in an amount of 5 at% to 7 at%, Bromine, wherein relative to the total content of the quantum dot complex, the bromine is contained in an amount of 2 at% to 4 at%, Iodine, wherein relative to the total content of the quantum dot complex, the iodine is contained in an amount of 1 at% to 2 at%, and Fluorine, wherein relative to the total content of the quantum dot complex, the fluorine is contained in an amount of 9 at% to 12 at%.

15. The display device according to claim 13, wherein: Relative to the total content of the quantum dot complex, the quantum dot complex has an organic content of 10 at% or more than 10 at%.

16. The display device according to claim 13, wherein: When the quantum dot complex emits red light, the valence band value of the quantum dot complex is -5.60 eV to -5.80 eV, When the quantum dot complex emits green light, the valence band value of the quantum dot complex is -5.73 eV to -5.93 eV, and When the quantum dot complex emits blue light, the valence band value of the quantum dot complex is -5.78 eV to -5.98 eV.

17. A method for producing a quantum dot complex, comprising: Providing quantum dots and a first ligand bound to the surface of the quantum dots; And Mixing and purifying the quantum dot complex in a first solution, wherein the first solution contains MX, Wherein: In the MX, M is any one of Na, Mg, K, Ca, Zn, In, Ga, Sn, and Sb, and X is any one of F, Cl, Br, and I, and when mixing and purifying the quantum dot complex in the first solution, a second ligand binds to the surface of the quantum dot, and the second ligand contains the X.

18. The method according to claim 17, wherein: the first solution contains a polar solvent, the polar solvent is methanol, ethanol, phenol, benzenediol, ethylene glycol, glycerol, diethylene glycol, triethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, or a combination thereof.

19. The method according to claim 17, wherein: the MX is provided at a concentration of 0.1 M to 0.5 M.

20. The method according to claim 17, further comprising: performing a surface treatment related to binding a third ligand to the surface of the quantum dot before mixing and purifying the quantum dot complex in the first solution.

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