Quantum dot composite, method for manufacturing quantum dot composite, and display device comprising quantum dot composite

Abstract

A quantum dot composite according to an embodiment of the present invention comprises: a quantum dot; and ligands bonded to the surface of the quantum dot, wherein a plurality of bonding parts to which the ligands are bonded are provided on the surface of the quantum dot. The bonding parts include a first bonding part and a second bonding part. The ligands include a first ligand bonded to the first bonding part and a second ligand bonded to the second bonding part, wherein the second ligand includes a halogen element, and the halogen element content is 1 at% to 12 at% with respect to the total amount of the quantum dot composite.

Description

Quantum dot complex, method for producing quantum dot complex, and display device including quantum dot complex

[0001] The present disclosure relates to a quantum dot complex, a method for producing a quantum dot complex, and a display device including the quantum dot complex.

[0002] A variety of display devices are being developed for use in multimedia devices such as televisions, mobile phones, tablet computers, navigation systems, and game consoles. These display devices utilize so-called self-luminous display elements that display information by emitting light from a luminescent material containing an organic compound.

[0003] In addition, development of display devices using quantum dots as light-emitting materials is in progress to improve the color reproducibility of display devices, and there is a demand for improving the light-emitting efficiency and lifespan of display devices using quantum dots.

[0004] The present invention provides a quantum dot composite with improved luminescence efficiency. It also provides a method for manufacturing a quantum dot composite with a simplified manufacturing process. It also provides a display device with improved luminescence efficiency.

[0005] According to one embodiment, a quantum dot complex comprises a quantum dot; and a ligand that binds to a surface of the quantum dot, wherein a plurality of binding sites to which the ligand binds are provided on the surface of the quantum dot, the binding sites include a first binding site and a second binding site, the ligand includes a first ligand that binds to the first binding site, and a second ligand that binds to the second binding site, and the second ligand includes a halogen element, and the halogen element is included in an amount of 1 at% to 12 at% based on the total content.

[0006] The halogen element is one of chlorine, fluorine, iodine, and bromine. When the halogen element is chlorine, the chlorine is included in an amount of 5 at% to 7 at% based on the total content of the quantum dot complex. When the halogen element is bromine, the bromine is included in an amount of 2 at% to 4 at% based on the total content of the quantum dot complex. When the halogen element is iodine, the iodine is included in an amount of 1 at% to 2 at% based on the total content of the quantum dot complex. When the halogen element is fluorine, the fluorine may be included in an amount of 9 at% to 12 at% based on the total content of the quantum dot complex.

[0007] The above quantum dot complex may have an organic content of 10 at% or more relative to the total content.

[0008] The quantum dot complex emits red light, and the valence band value of the quantum dot complex may be between -5.60 eV and -5.80 eV.

[0009] The quantum dot complex emits green light, and the valence band value of the quantum dot complex may be between -5.73 eV and -5.93 eV.

[0010] The quantum dot complex emits blue light, and the valence band value of the quantum dot complex may be between -5.78 eV and -5.98 eV.

[0011] The above binding portion may further include a third binding portion, and the ligand may further include a third ligand that is bound to the second binding portion or the third binding portion.

[0012] The third ligand may comprise any one selected from phosphine and phosphine oxide.

[0013] The third ligand may further include 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 thiol group, a substituted or unsubstituted oxy group, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

[0014] The quantum dot may include a core and a shell surrounding the core.

[0015] The above-mentioned joint may be provided on the surface of the shell.

[0016] The core comprises a first semiconductor nanocrystal, the shell comprises 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 a group II-VI compound, a group III-V compound, a group IV-VI compound, a group IV element, a group IV compound, and a combination thereof.

[0017] A display device according to one embodiment includes a first electrode, an emission layer positioned on the first electrode, and a second electrode positioned on the emission layer, wherein the emission layer includes a quantum dot complex, wherein the quantum dot complex includes: a quantum dot; and a ligand bonded to a surface of the quantum dot, wherein a plurality of binding sites to which the ligand binds are provided on the surface of the quantum dot, wherein the binding sites include a first binding site and a second binding site, wherein the ligand includes a first ligand bonded to the first binding site and a second ligand bonded to the second binding site, and wherein the second ligand includes a halogen element, and the halogen element is included in an amount of 1 at% to 12 at% based on the total content.

[0018] The halogen element may be one of chlorine, fluorine, iodine, and bromine, and the chlorine may be included in an amount of 5 at% to 7 at% 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% based on the total content of the quantum dot complex, and the fluorine may be included in an amount of 9 at% to 12 at% based on the total content of the quantum dot complex.

[0019] The above quantum dot complex may have an organic content of 10 at% or more relative to the total content.

[0020] When the quantum dot complex emits red light, the valence band value of the quantum dot complex may be -5.60 eV to -5.80 eV, when the quantum dot complex emits green light, the valence band value of the quantum dot complex may be -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.

[0021] A method for manufacturing a quantum dot complex according to one embodiment includes the steps of providing a quantum dot complex having a first ligand bound to a surface of a quantum dot, and mixing and purifying the quantum dot complex in a first solution, wherein the first solution includes MX, wherein M in MX 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 in the step of mixing and purifying the quantum dot complex in the first solution, a second ligand is bound to the surface of the quantum dot.

[0022] The first solution comprises a polar solvent, and the polar solvent may comprise methanol, ethanol, phenol, benzenediol, ethylene glycol, glycerol, diethylene glycol, triethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether or a combination thereof.

[0023] The above MX can be provided at a concentration of 0.1 M to 0.5 M.

[0024] A surface treatment step may be further included to bind a third ligand to the surface of the quantum dot before the step of mixing the quantum dot complex into the first solution and purifying it.

[0025] According to the embodiments, a quantum dot composite with improved luminescence efficiency can be provided. Furthermore, a method for manufacturing a quantum dot composite with a simplified manufacturing process can reduce manufacturing costs and manufacturing time. Furthermore, a display device with improved luminescence efficiency can be provided.

[0026] FIG. 1 is a schematic diagram of a quantum dot complex according to one embodiment.

[0027] FIG. 2 is a cross-sectional view of a quantum dot complex according to one embodiment.

[0028] FIG. 3, FIG. 4, and FIG. 5 are each an enlarged cross-sectional view of a portion of a quantum dot complex according to one embodiment.

[0029] Figure 6 is a cross-sectional view of a quantum dot complex according to another embodiment.

[0030] Figure 7 is an enlarged cross-sectional view of a portion of a quantum dot complex according to another embodiment.

[0031] Figure 8 is a schematic cross-sectional view of a light emitting element according to one embodiment.

[0032] Figure 9 is a schematic cross-sectional view of a display device according to one embodiment.

[0033] Figure 10 is a flowchart of a manufacturing process of a quantum dot complex according to one embodiment.

[0034] Figure 11 is a schematic drawing of a quantum dot complex according to the manufacturing process of Figure 10.

[0035] Figure 12 is a flowchart of a manufacturing process of a quantum dot complex according to one embodiment.

[0036] Figure 13 is a schematic drawing of a quantum dot complex according to the manufacturing process of Figure 12.

[0037] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the invention. The present invention may be implemented in various different forms and is not limited to the embodiments described herein.

[0038] In order to clearly explain the present invention, parts that are not related to the description are omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0039] Furthermore, the sizes and thicknesses of each component shown in the drawings are arbitrarily indicated for convenience of explanation, and thus the present invention is not necessarily limited to the illustrated components. In the drawings, the thicknesses are enlarged to clearly represent various layers and regions. Furthermore, in the drawings, the thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0040] Furthermore, when we say that a layer, membrane, region, plate, or other part is "above" or "on" another part, this includes not only cases where it is "directly above" the other part, but also cases where there are other parts in between. Conversely, when we say that a part is "directly above" another part, we mean that there are no other parts in between. Furthermore, saying that a part is "above" or "on" a reference part means that it is located above or below the reference part, and does not necessarily mean that it is located "above" or "on" the opposite direction of gravity.

[0041] Additionally, throughout the specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0042] Additionally, throughout the specification, when we say "in plan", we mean when the target portion is viewed from above, and when we say "in cross section", we mean when the target portion is viewed from the side in a cross-section cut vertically.

[0043] Hereinafter, a quantum dot complex according to an embodiment will be described with reference to FIGS. 1 to 5. FIG. 1 is a schematic drawing of a quantum dot complex according to an embodiment, FIG. 2 is a cross-sectional view of a quantum dot complex according to an embodiment, and FIGS. 3, 4, and 5 are each an enlarged cross-sectional view of a portion of a quantum dot complex according to an embodiment.

[0044] Referring to FIGS. 1 and 2, a quantum dot complex (QDC) according to one embodiment may include a quantum dot (QD) and a ligand (LD) bound to the surface of the quantum dot (QD). The quantum dot complex (QDC) may have modified surface properties in which a ligand (LD) containing a functional group is attached to the surface of the quantum dot (QD). The quantum dot complex (QDC) may be referred to as a surface-modified quantum dot.

[0045] A quantum dot (QD) may include a core (CR) and a shell (SL) surrounding the core (CR). However, the embodiment is not limited thereto, and the quantum dot (QD) may have a single-layer structure or may have multiple shells.

[0046] In the present specification, a quantum dot may include 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.

[0047] The above II-VI group compound is 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; And it may be selected from the group consisting of a four-element compound selected from the group consisting of HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe and mixtures thereof. The group II-VI compound may further include a group III metal.

[0048] The above III-V group compound may be selected from the group consisting of 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; and 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. The above group III-V compound may further comprise a group II metal (e.g., InZnP).

[0049] The above IV-VI group compound may be selected from the group consisting of a binary compound selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, and mixtures thereof; a ternary compound selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and mixtures thereof; and a quaternary compound selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe, and mixtures thereof.

[0050] The above group IV element or compound may be selected from the group consisting of a single element compound selected from the group consisting of Si, Ge, and combinations thereof; and a binary element compound selected from the group consisting of SiC, SiGe, and combinations thereof, but is not limited thereto.

[0051] Examples of the above Group I-III-VI compounds include, but are not limited to, AgInGaS, CuInSe2, CuInS2, CuInGaSe, and CuInGaS. Examples of the above Group I-II-IV-VI compounds include, but are not limited to, CuZnSnSe, and CuZnSnS. The Group IV element or compound may be selected from the group consisting of a single element selected from the group consisting of Si, Ge, and mixtures thereof; and a binary compound selected from the group consisting of SiC, SiGe, and mixtures thereof.

[0052] The above group II-III-VI compound may be selected from the group consisting of, but is not limited to, 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.

[0053] The above group I-II-IV-VI compound may be selected from CuZnSnSe and CuZnSnS, but is not limited thereto.

[0054] In quantum dots, the aforementioned binary, ternary, and / or quaternary compounds may exist within the particle at a uniform concentration, or may exist within the same particle with partially different concentration distributions. Furthermore, one quantum dot may have a core / shell structure surrounding another quantum dot. The interface between the core and shell may have a concentration gradient, with the concentration of the element in the shell decreasing toward the center.

[0055] In some embodiments, the quantum dot may have a core-shell structure comprising a core including the aforementioned nanocrystals and a shell surrounding the core. The shell of the quantum dot may function as a protective layer to maintain semiconductor properties by preventing chemical modification of the core and / or as a charging layer to impart electrophoretic properties to the quantum dot. The shell may be a single layer or a multilayer. The interface between the core and the shell may have a concentration gradient in which the concentration of elements present in the shell decreases toward the center. Examples of the shell of the quantum dot include a metal or non-metal oxide, a semiconductor compound, or a combination thereof.

[0056] For example, the oxide of the metal or non-metal may be a binary compound such as SiO2, Al2O3, TiO2, ZnO, MnO, Mn2O3, Mn3O4, CuO, FeO, Fe2O3, Fe3O4, CoO, Co3O4, NiO, or a ternary compound such as MgAl2O4, CoFe2O4, NiFe2O4, CoMn2O4, but the present invention is not limited thereto. In addition, the semiconductor compound may be a compound such as CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnSeS, ZnTeS, GaAs, GaP, GaSb, HgS, HgSe, HgTe, InAs, InP, InGaP, InSb, AlAs, AlP, AlSb, but the present invention is not limited thereto.

[0057] The interface between the core and the shell may have a concentration gradient in which the concentration of elements present in the shell decreases toward the center. In addition, the semiconductor nanocrystal may have a structure including a single semiconductor nanocrystal core and a multilayer shell surrounding the core. In one embodiment, the multilayer shell may have two or more layers, for example, two, three, four, five, or more layers. Adjacent two layers of the shell may have a single composition or different compositions. Each layer in the multilayer shell may have a composition that varies along the radius.

[0058] Quantum dots can have a full width of half maximum (FWHM) of an emission wavelength spectrum of about 45 nm or less, preferably about 40 nm or less, and more preferably about 30 nm or less, and color purity and color reproducibility can be improved within this range. In addition, since light emitted by these quantum dots is emitted in all directions, a wide viewing angle can be improved.

[0059] The quantum dot may have different energy band gaps for the shell material and the core material. For example, the energy band gap of the shell material may be larger than that of the core material. In another embodiment, the energy band gap of the shell material may be smaller than that of the core material. The quantum dot may have a multilayer shell. In the multilayer shell, the energy band gap of the outer layer may be larger than that of the inner layer (i.e., the layer closer to the core). In the multilayer shell, the energy band gap of the outer layer may be smaller than the energy band gap of the inner layer.

[0060] Quantum dots can have their absorption / emission wavelengths controlled by adjusting their composition and size. The maximum emission peak wavelength of the quantum dots can range from ultraviolet to infrared wavelengths or even beyond.

[0061] Quantum dots can have a quantum efficiency of greater than or equal to about 10%, for example, greater than or equal to about 30%, greater than or equal to about 50%, greater than or equal to about 60%, greater than or equal to about 70%, greater than or equal to about 90%, or even greater than or equal to 100%. Quantum dots can have a relatively narrow spectrum. Quantum dots can have a half-width of an emission wavelength spectrum of, for example, less than or equal to about 50 nm, less than or equal to about 45 nm, less than or equal to about 40 nm, or less than or equal to about 30 nm.

[0062] The quantum dot may have a particle size of about 1 nm or more and about 100 nm or less. The particle size refers to the diameter of the particle or the diameter converted assuming a spherical shape from a two-dimensional image obtained by transmission electron microscopy analysis. The quantum dot may have a size of about 1 nm to about 20 nm, for example, 2 nm or more, 3 nm or more, or 4 nm or more and 50 nm or less, 40 nm or less, 30 nm or less, 20 nm or less, 15 nm or less, for example, 10 nm or less. The shape of the quantum dot is not particularly limited. For example, the shape of the quantum dot may include, but is not limited to, a sphere, a polyhedron, a pyramid, a multipod, a square, a rectangular parallelepiped, a nanotube, a nanorod, a nanowire, a nanosheet, or a combination thereof.

[0063] Quantum dots are commercially available or can be synthesized appropriately. During colloidal synthesis, the particle size of quantum dots can be relatively freely controlled, and the particle size can be uniformly controlled.

[0064] A quantum dot complex (QDC) according to one embodiment may include a ligand (LD) bound to the surface of a quantum dot (QD). The ligand (LD) according to one embodiment may include a first ligand (LD1) and a second ligand (LD2). Each of the first ligand (LD1) and the second ligand (LD2) may be bound to different binding sites (ST) provided on the surface of the quantum dot (QD).

[0065] In one embodiment, the shell (SL) of a quantum dot (QD) can provide a plurality of binding sites (ST). The plurality of binding sites (ST) include a first binding site (ST1), a second binding site (ST2), and a third binding site (ST3), and the first ligand (LD1) can bind to the first binding site (ST1), and the second ligand (LD2) can bind to the second binding site (ST2) or the third binding site (ST3).

[0066] Figures 3 to 5 schematically illustrate the form in which a ligand (LD) is bound to the surface of a quantum dot (QD) in a quantum dot complex (QDC). Figure 3 is an enlarged view of part A of Figure 2, Figure 4 is an enlarged view of part B of Figure 2, and Figure 5 is an enlarged view of part C of Figure 2.

[0067] Referring to FIGS. 3 to 5, the plurality of bonding sites (ST) provided on the surface of the shell (SL) of the quantum dot (QD) may be defective portions exposed on the surface of the semiconductor nanocrystals included in the shell (SL). Unlike atoms existing in a completely crystalline state inside the shell (SL), the plurality of bonding sites (ST) may have dangling bonds, in which some bonds are broken due to coordination unsaturation on the surface of the shell (SL). In one embodiment, the shell (SL) includes a group II-VI compound, a group III-V compound, a group IV-VI compound, etc., and each of the group II, III, IV, V, and VI elements included in the shell (SL) may be exposed in a coordination unsaturated state, or may be exposed in a coordination unsaturated state by bonding with a corresponding element, thereby providing the plurality of bonding sites (ST). The plurality of bonding portions (ST) included in the shell (SL) may include a first bonding portion (ST1) in which a cation is exposed, a second bonding portion (ST2) in which an anion is exposed, and a third bonding portion (ST3) in the form of a defect such as a vacancy.

[0068] Referring to Fig. 3, the first ligand (LD1) is bonded to the first binding portion (ST1), and the first binding portion (ST1) may be a defective portion where a cation is exposed. In Fig. 3, it is exemplarily illustrated that the shell (SL) includes ZnS, and the first binding portion (ST1) is a Zn cation. However, the present invention is not limited thereto, and the first binding portion (ST1) may be at least one selected from among a Zn cation, a Cd cation, a Hg cation, a Mg cation, an Ag cation, a Cu cation, a Ga cation, an Al cation, an In cation, a Sn cation, and a Pb cation.

[0069] For example, the first ligand (LD1) may include an electron-donating functional group to bind to the first binding portion (ST1), which is a cation-exposed defective portion. The first ligand (LD1) may include 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 thiol group, a substituted or unsubstituted oxy group, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms. 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. In one embodiment, the first ligand (LD1) may be oleic acid.

[0070] Meanwhile, in the present specification, "substituted or unsubstituted" may mean substituted or unsubstituted with one or more substituents selected from the group consisting of 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. In addition, each of the above-mentioned substituents may be substituted or unsubstituted. For example, a biphenyl group may be interpreted as an aryl group, or may be interpreted as a phenyl group substituted with a phenyl group.

[0071] Referring to FIG. 4, the second ligand (LD2) is bonded to the second binding portion (ST2), and the second binding portion (ST2) may be a defective portion where an anion is exposed. In FIG. 4, the shell (SL) includes ZnS, and the second binding portion (ST2) is exemplarily illustrated as an S anion. However, the present invention is not limited thereto, and the second binding portion (ST2) may be at least one selected from the group consisting of an S anion, a Se anion, a Te anion, an N anion, a P anion, an As anion, and a Sb anion. The second ligand (LD2) may include, for example, a halogen element, and may include, for example, at least one of fluorine, chlorine, bromine, and iodine.

[0072] Depending on the type of the halogen element, the energy band position of the quantum dot complex (QDC) can be controlled. The halogen element can control the dipole on the surface of the quantum dot complex, and thus the energy band position of the quantum dot complex is controlled. Generally, when a halogen element is introduced, the energy band position shifts in the negative direction, and the degree of shift can be controlled by the electron affinity of the halogen atom and the amount introduced into the quantum dot complex.

[0073] Referring to Fig. 5, the second ligand (LD2) can bind to a third binding site (ST3) in addition to the second binding site (ST2). The third binding site (ST3) may be a defect such as a vacancy or an exposed defect in which cations and anions are bound. The third binding site (ST3) may be a defect such as a vacancy or an exposed defect in which cations and anions included in a shell (SL) bind to form a crystal, but some of the bonds are broken due to coordination unsaturation.

[0074] In one embodiment, a quantum dot complex (QDC) may include a halogen element via a second ligand (LD2). The quantum dot complex (QDC) may include a halide in an amount of 1 at% to 12 at% relative to the total content. For example, the quantum dot complex (QDC) may include chlorine (Cl) in an amount of 5 at% to 7 at% relative to the total content of the quantum dot complex, 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% relative to the total content of the quantum dot complex.

[0075] A quantum dot complex (QDC) according to one embodiment may include an organic material by virtue of the first ligand (LD1). For example, the quantum dot complex (QDC) may include an organic material in an amount of 10 at% or more relative to the total amount of the quantum dot complex. The quantum dot complex (QDC) according to one embodiment may have appropriate solubility because it includes a sufficient amount of the first ligand (LD1).

[0076] In one embodiment, a quantum dot complex (QDC) can control the color of light emitted depending on the particle size of the quantum dot (QD), and accordingly, the quantum dot (QD) can have various emission colors such as blue, red, and green. The smaller the particle size of the quantum dot (QD), the more it can emit light in a shorter wavelength range. For example, in quantum dots (QDs) having the same core, the particle size of a quantum dot that emits green light may be smaller than the particle size of a quantum dot that emits red light. In addition, in quantum dots (QDs) having the same core, the particle size of a quantum dot that emits blue light may be smaller than the particle size of a quantum dot that emits green light. However, the embodiment is not limited thereto, and even in quantum dots (QDs) having the same core, the particle size may be controlled depending on the forming material of the shell, the shell thickness, etc.

[0077] Meanwhile, when quantum dots (QDs) have various emission colors such as blue, red, and green, quantum dots (QDs) with different emission colors may have different core materials.

[0078] When the quantum dot complex (QDC) according to one embodiment emits red light, the valence band of the quantum dot complex (QDC) may be about -5.60 eV to -5.80 eV. When the quantum dot complex (QDC) according to one embodiment emits green light, the valence band of the quantum dot complex (QDC) may be about -5.73 eV to -5.93 eV. When the quantum dot complex (QDC) according to one embodiment emits blue light, the valence band of the quantum dot complex (QDC) may be about -5.78 eV to -5.98 eV.

[0079] A quantum dot complex according to one embodiment includes a first ligand and a second ligand stably bound to the surface of a quantum dot, thereby enabling provision of a quantum dot complex having improved light efficiency.

[0080] Hereinafter, a quantum dot composite according to another embodiment will be described with reference to FIGS. 6 and 7. FIG. 6 is a cross-sectional view of a quantum dot composite according to another embodiment, and FIG. 7 is an enlarged cross-sectional view of a portion of a quantum dot composite according to another embodiment. Descriptions of components identical to those described above will be omitted.

[0081] Referring to FIG. 6, a quantum dot complex (QDC) according to one embodiment may include a quantum dot (QD) and a ligand (LD) bound to the surface of the quantum dot (QD). The quantum dot complex (QDC) may have modified surface properties, in which a ligand (LD) containing a functional group is attached to the surface of the quantum dot (QD). The quantum dot complex (QDC) may be referred to as a surface-modified quantum dot.

[0082] A quantum dot (QD) may include a core (CR) and a shell (SL) surrounding the core (CR). However, the embodiment is not limited thereto, and the quantum dot (QD) may have a single-layer structure or may have multiple shells.

[0083] A quantum dot complex (QDC) according to one embodiment may include a ligand (LD) bound to the surface of a quantum dot (QD). The ligand (LD) according to one embodiment may include a first ligand (LD1), a second ligand (LD2), and a third ligand (LD3). Each of the first ligand (LD1), the second ligand (LD2), and the third ligand (LD3) may be bound to different binding sites (ST) provided on the surface of the quantum dot (QD).

[0084] In one embodiment, the shell (SL) of a quantum dot (QD) can provide a plurality of binding sites (ST). The plurality of binding sites (ST) include a first binding site (ST1), a second binding site (ST2), and a third binding site (ST3), wherein the first ligand (LD1) can bind to the first binding site (ST1), the second ligand (LD2) can bind to the second binding site (ST2) or the third binding site (ST3), and the third ligand (LD3) can bind to the second binding site (ST2) or the third binding site (ST3).

[0085] FIG. 7 is an enlarged view of part D of FIG. 6. The third ligand (LD3) according to one embodiment may include any one selected from phosphine, phosphine oxide, imidazole, and pyridine that is bound to the surface of a quantum dot (QD). In addition, the third ligand (LD3) may further include 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 thiol group, a substituted or unsubstituted oxy group, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

[0086] In one embodiment, the quantum dot complex (QDC) may include a halogen element via the second ligand (LD2). For example, the quantum dot complex (QDC) may include chlorine (Cl) in an amount of 5 at% to 7 at% relative to the total content of the quantum dot complex, 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%.

[0087] A quantum dot complex (QDC) according to one embodiment may include an organic material by the first ligand (LD1) and the third ligand (LD3). For example, the quantum dot complex (QDC) may include an organic material in an amount of 10 at% or more relative to the total amount of the quantum dot complex. The quantum dot complex (QDC) according to one embodiment may have appropriate solubility because it includes a sufficient amount of the first ligand (LD1) and the third ligand (LD3).

[0088] In one embodiment, a quantum dot complex (QDC) can control the color of light emitted depending on the particle size of the quantum dot (QD), and thus the quantum dot (QD) can have various emission colors such as blue, red, and green. The smaller the particle size of the quantum dot (QD), the more it can emit light in a shorter wavelength range. For example, in quantum dots (QD) having the same core, the particle size of a quantum dot that emits green light may be smaller than the particle size of a quantum dot that emits red light. Furthermore, in quantum dots (QD) having the same core, the particle size of a quantum dot that emits blue light may be smaller than the particle size of a quantum dot that emits green light. However, the embodiment is not limited thereto, and even in quantum dots (QD) having the same core, the particle size may be controlled depending on the shell forming material and shell thickness, etc. Meanwhile, when quantum dots (QD) have various emission colors such as blue, red, and green, quantum dots (QD) having different emission colors may have different core materials.

[0089] When the quantum dot complex (QDC) according to one embodiment emits red light, the valence band of the quantum dot complex (QDC) may be about -5.60 eV to -5.80 eV. When the quantum dot complex (QDC) according to one embodiment emits green light, the valence band of the quantum dot complex (QDC) may be about -5.73 eV to -5.93 eV. When the quantum dot complex (QDC) according to one embodiment emits blue light, the valence band of the quantum dot complex (QDC) may be about -5.78 eV to -5.98 eV.

[0090] A quantum dot complex according to one embodiment includes a first ligand, a second ligand, and a third ligand stably bound to a quantum dot surface, thereby enabling provision of a quantum dot complex having improved light efficiency.

[0091] Hereinafter, a display device according to one embodiment will be described with reference to FIGS. 8 and 9. FIG. 8 is a schematic cross-sectional view of a light-emitting element according to one embodiment, and FIG. 9 is a schematic cross-sectional view of a display device according to one embodiment.

[0092] First, referring to FIG. 8, a display device according to one embodiment may include a light-emitting element (LD). The light-emitting element (LD) includes a first electrode (E1), a light-emitting layer (EML), and a second electrode (E2).

[0093] The first electrode (E1) is also called an anode electrode and may be composed of a single layer including a transparent conductive oxide film or a metal material or a multilayer including them. The transparent conductive oxide film may include indium tin oxide (ITO), poly-ITO, indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), and indium tin zinc oxide (ITZO). The metal material may include silver (Ag), molybdenum (Mo), copper (Cu), gold (Au), and aluminum (Al).

[0094] The first electrode (E1) may be electrically connected to a pixel circuit (PC) located at a lower portion of the first electrode (E1). The pixel circuit (PC) may include a transistor, and the first electrode (E1) may receive an output current to be transmitted from the pixel circuit (PC) to the light-emitting layer (EML).

[0095] A pixel defining layer (PDL) may be positioned on the first electrode (E1). The pixel defining layer (PDL) includes an opening that overlaps at least a portion of the first electrode (E1). The pixel defining layer (PDL) may define a formation location of the light emitting layer (EML) so that the light emitting layer (EML) may be positioned on a portion of the upper surface of the first electrode (E1) exposed.

[0096] The emission layer (EML) may be positioned within a pixel aperture defined by a pixel defining layer (PDL). In one embodiment, the emission layer (EML) may include the quantum dot complex described above. Although the emission layer (EML) is illustrated as a single layer in FIG. 8, in reality, auxiliary layers such as an electron injection layer, an electron transport layer, a hole transport layer, and a hole injection layer may also be included above and below the emission layer (EML), and the hole injection layer and the hole transport layer may be positioned below the emission layer (EML), and the electron transport layer and the electron injection layer may be positioned above the emission layer (EML).

[0097] The second electrode (E2) may be positioned on the pixel defining layer (PDL) and the emission layer (EML). The second electrode (E2) is also called a cathode electrode and may be formed of a transparent conductive layer including ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), IGZO (Indium Gallium Zinc Oxide), and ITZO (Indium Tin Zinc Oxide). In addition, the second electrode (E2) may have a translucent characteristic, and in this case, it may form a micro cavity together with the first electrode (E1). According to the micro cavity structure, light of a specific wavelength is emitted upwards depending on the gap and characteristics between the two electrodes, and as a result, red, green, or blue can be displayed.

[0098] Referring to the following Figure 9, a display device according to one embodiment may include a pixel circuit unit (PC), a light-emitting element (ED) connected to the pixel circuit unit (PC), and a color conversion unit (CCL) positioned on the light-emitting element (ED). Components identical to the aforementioned components will be omitted.

[0099] According to one embodiment, the light-emitting layer (EML) may include an organic material that emits red, green, blue, or the like light. The light-emitting layer (EML) that emits red, green, or blue light may include a low-molecular-weight or high-molecular-weight organic material. Although the light-emitting layer (EML) is illustrated as a single layer in FIG. 9, in reality, auxiliary layers such as an electron injection layer, an electron transport layer, a hole transport layer, and a hole injection layer may also be included above and below the light-emitting layer (EML), and the hole injection layer and the hole transport layer may be positioned below the light-emitting layer (EML), and the electron transport layer and the electron injection layer may be positioned above the light-emitting layer (EML).

[0100] An encapsulation layer (ENC) may be positioned on the second electrode (E2). The encapsulation layer (ENC) may include at least one inorganic film and at least one organic film.

[0101] A display device according to one embodiment may include a color conversion layer (CCL) overlapping a light emitting element (ED). The color conversion layer (CCL) may include the above-described quantum dot complex. For example, a color conversion layer (CCL) positioned in a red light emitting region may include a red quantum dot complex, and a color conversion layer (CCL) positioned in a green light emitting region may include a green quantum dot complex. A partition wall (BM) may be positioned between adjacent color conversion layers (CCL), and may include a black material to block light and prevent color mixing between adjacent light emitting regions.

[0102] A display device including the quantum dot complex described above can provide improved luminous efficiency.

[0103] Hereinafter, a method for manufacturing a quantum dot complex according to an embodiment will be described with reference to FIGS. 10 and 11. FIG. 10 is a flowchart illustrating a manufacturing process for a quantum dot complex according to an embodiment, and FIG. 11 is a schematic diagram of a quantum dot complex according to the manufacturing process of FIG. 10.

[0104] Referring to FIG. 10, a quantum dot complex according to one embodiment can be manufactured through a step (S1) of forming a quantum dot complex to which a first ligand (LD1) is bound, and a step (S2) of mixing and purifying the quantum dot complex with a first solution containing a second ligand.

[0105] Referring to FIG. 10 and FIG. 11, a quantum dot (QD) may be provided in the form of a quantum dot complex (QDC) including a first ligand (LD1) on the surface. In this case, most of the first ligand (LD1) may be provided in a form bound to a first binding portion (ST1).

[0106] Thereafter, the quantum dot complex (QDC) containing the first ligand (LD1) can be purified by mixing it with the first solution containing MX. This allows the quantum dot complex (QDC) to contain the second ligand (LD2) that binds to the second binding site (ST2) while simultaneously undergoing the purification process. The purification process can remove unnecessary byproducts and excess ligands.

[0107] In the above MX, M may be any one of Na, Mg, K, Ca, Zn, In, Ga, Sn, and Sb, and X may be any one of F, Cl, Br, and I. The MX may be provided in a concentration of 0.1 M to 0.5 M in a polar solvent. The polar solvent may include, but is not limited to, methanol, ethanol, phenol, benzenediol, ethylene glycol, glycerol, diethylene glycol, triethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, or any combination thereof.

[0108] Through this manufacturing process, the quantum dot complex (QDC) described in FIGS. 1 to 5 can be obtained.

[0109] The quantum dot complex (QDC) manufactured through the above-described manufacturing method may include a halogen element by the second ligand (LD2). For example, the quantum dot complex (QDC) may include chlorine (Cl) in an amount of 5 at% to 7 at% relative to the total content of the quantum dot complex, 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%.

[0110] The quantum dot complex (QDC) manufactured through the above-described manufacturing method may include an organic material due to the first ligand (LD1). For example, the quantum dot complex (QDC) may include an organic material in an amount of 10 at% or more relative to the total amount of the quantum dot complex. According to one embodiment, the quantum dot complex (QDC) may have appropriate solubility because it includes a sufficient amount of the first ligand (LD1).

[0111] When the quantum dot complex (QDC) manufactured through the above-described manufacturing method emits red light, the valence band of the quantum dot complex (QDC) may be about -5.70 eV. When the quantum dot complex (QDC) according to one embodiment emits green light, the valence band of the quantum dot complex (QDC) may be about -5.83 eV. When the quantum dot complex (QDC) according to one embodiment emits blue light, the valence band of the quantum dot complex (QDC) may be about -5.88 eV.

[0112] When a separate surface treatment process is performed to include a second ligand, the valence band of the quantum dot complex (QDC) emitting red light may be about -5.20 to -5.33 eV, the valence band of the quantum dot complex (QDC) emitting green light may be about -5.35 to -5.48 eV, and the valence band of the quantum dot complex (QDC) emitting blue light may be about -6.25 to -6.36 eV.

[0113] According to a manufacturing method according to one embodiment, the valence band of a quantum dot complex (QDC) emitting red light may be negatively shifted by about 0.37 to 0.50 eV, the valence band of a quantum dot complex (QDC) emitting green light may be negatively shifted by about 0.35 to 0.48 eV, and the valence band of a quantum dot complex (QDC) emitting blue light may be negatively shifted by about 0.37 to 0.48 eV.

[0114] Typically, after forming a quantum dot complex comprising a first ligand, the quantum dot complex is surface-treated at high temperatures to incorporate a second ligand, followed by a purification process. However, this process can result in the removal of the first ligand during the surface treatment of the second ligand, thereby reducing the efficiency of the quantum dot complex.

[0115] However, in one embodiment, the quantum dot complex can be surface-treated to incorporate a second ligand during a purification process performed at room temperature. This simplifies the manufacturing process for binding the second ligand, and allows the first and second ligands to be stably bound to the quantum dot complex, thereby providing a quantum dot complex with enhanced efficiency.

[0116] Hereinafter, a method for manufacturing a quantum dot complex according to another embodiment will be described with reference to FIGS. 12 and 13. FIG. 12 is a flowchart illustrating a manufacturing process for a quantum dot complex according to an embodiment, and FIG. 13 is a schematic drawing of a quantum dot complex according to the manufacturing process of FIG. 12.

[0117] Referring to FIG. 12, a manufacturing process of a quantum dot complex according to one embodiment may be manufactured through a step (S1) of providing a quantum dot complex to which a first ligand (LD1) is bound, a step (S2) of surface treatment to bind a third ligand (LD3) to the quantum dot complex, and a step (S3) of mixing and purifying the quantum dot complex with a first solution containing a second ligand. Compared to the manufacturing process described above, a step (S2) of surface treatment to bind a third ligand (LD3) to the quantum dot complex may be further included.

[0118] Referring to FIG. 12 and FIG. 13, a quantum dot (QD) may be provided in the form of a quantum dot complex (QDC) including a first ligand (LD1) on the surface. In this case, most of the first ligand (LD1) may be provided in a form bound to a first binding portion (ST1).

[0119] Thereafter, the quantum dot complex (QDC) is mixed with a solution containing a third ligand (LD3) and an organic solvent and reacted at room temperature for about 30 minutes. The organic solvent may include hexane, toluene, chloroform, dimethyl sulfoxide, or dimethyl formamide. However, the examples are not limited thereto.

[0120] The third ligand (LD3) may include any one selected from phosphine, phosphine oxide, imidazole, and pyridine that is bound to the surface of the quantum dot (QD). In addition, the third ligand (LD3) may include 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 thiol group, a substituted or unsubstituted oxy group, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

[0121] The quantum dot complex (QDC) that has undergone this surface treatment process may be in a form that includes a first ligand (LD1) and a third ligand (LD3).

[0122] Thereafter, a quantum dot complex (QDC) comprising a first ligand (LD1) and a third ligand (LD3) can be provided dispersed in a first solution containing MX. This allows for obtaining a quantum dot complex (QDC) comprising a second ligand (LD2) and simultaneously performing a purification process. The purification process can remove unnecessary byproducts and excess ligands.

[0123] In the above MX, M may be any one of Na, Mg, K, Ca, Zn, In, Ga, Sn, and Sb, and X may be any one of F, Cl, Br, and I. The MX may be provided in a concentration of 0.1 M to 0.5 M in the polar solvent. The polar solvent may include, but is not limited to, methanol, ethanol, phenol, benzenediol, ethylene glycol, glycerol, diethylene glycol, triethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, or any combination thereof.

[0124] Through this manufacturing process, the quantum dot complex (QDC) described in FIGS. 6 to 7 can be obtained.

[0125] The quantum dot complex (QDC) manufactured through the above-described manufacturing method may include a halogen element by the second ligand (LD2). For example, the quantum dot complex (QDC) may include chlorine (Cl) in an amount of 5 at% to 7 at% relative to the total content of the quantum dot complex, 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%.

[0126] The quantum dot complex (QDC) manufactured through the above-described manufacturing method may include an organic material by the first ligand (LD1) and the third ligand (LD3). For example, the quantum dot complex (QDC) may include an organic material in an amount of 10 at% or more based on the total amount of the quantum dot complex. The quantum dot complex (QDC) according to one embodiment may have appropriate solubility because it includes a sufficient amount of the first ligand (LD1) and the third ligand (LD3).

[0127] When the quantum dot complex (QDC) manufactured through the above-described manufacturing method emits red light, the valence band of the quantum dot complex (QDC) may be about -5.70 eV. When the quantum dot complex (QDC) according to one embodiment emits green light, the valence band of the quantum dot complex (QDC) may be about -5.83 eV. When the quantum dot complex (QDC) according to one embodiment emits blue light, the valence band of the quantum dot complex (QDC) may be about -5.88 eV.

[0128] Unlike the manufacturing method according to one embodiment, when a separate surface treatment process is performed to include a second ligand, the valence band of the quantum dot complex (QDC) emitting red light may be about -5.20 to -5.33 eV, the valence band of the quantum dot complex (QDC) emitting green light may be about -5.35 to -5.48 eV, and the valence band of the quantum dot complex (QDC) emitting blue light may be about -6.25 to -6.36 eV.

[0129] According to a manufacturing method according to one embodiment, the valence band of a quantum dot complex (QDC) emitting red light may be negatively shifted by about 0.37 to 0.50 eV, the valence band of a quantum dot complex (QDC) emitting green light may be negatively shifted by about 0.35 to 0.48 eV, and the valence band of a quantum dot complex (QDC) emitting blue light may be negatively shifted by about 0.37 to 0.48 eV.

[0130] Typically, after forming a quantum dot complex comprising a first ligand, surface treatment is performed at high temperatures to allow the quantum dot complex to comprise a second ligand and a third ligand, followed by a purification process. However, this process can result in the removal of the first ligand during the surface treatment of the second and third ligands, thereby reducing the efficiency of the quantum dot complex.

[0131] However, in one embodiment, the quantum dot complex can be surface-treated to incorporate a second ligand during a purification process performed at room temperature. This simplifies the manufacturing process for binding the second ligand, and allows the first, second, and third ligands to be stably bound to the quantum dot complex, thereby providing a quantum dot complex with enhanced efficiency.

[0132]

[0133] Hereinafter, Comparative Example 1, Comparative Example 2, Examples 1 and 2 will be described with reference to Table 1. Comparative Example 1 is a quantum dot complex obtained by purifying blue quantum dots in the form of ZnTeSe / ZnSe / ZnS using ethanol, Comparative Example 2 is a quantum dot complex obtained by surface-treating blue quantum dots in the form of ZnTeSe / ZnSe / ZnS with ZnCl2 and then purifying them using ethanol, Example 1 is a quantum dot complex obtained by purifying blue quantum dots in the form of ZnTeSe / ZnSe / ZnS using ethanol containing ZnCl2, and Example 2 is a quantum dot complex obtained by purifying blue quantum dots in the form of ZnTeSe / ZnSe / ZnS using ethanol containing ZnI2.

[0134]

[0135] Classification Comparison Example 1 Comparison Example 2 Example 1 Example 2 PLQY 38% 45% 71% 82% Valance Band - 5.79 eV - 5.88 eV - 6.36 eV - 6.25 eV Organic Content 14.87% 9.04% 10.88% 11.85%

[0136] Referring to Table 1, it was confirmed that the light efficiencies of Examples 1 and 2 were 71% and 82%, which was significantly improved compared to Comparative Example 1 (38%) and Comparative Example 2 (45%). In addition, it was confirmed that the valence band values ​​of Examples 1 and 2 were negatively shifted compared to Comparative Example 1 and Comparative Example 2. This is due to an increase in the amount of the surface-treated second ligand. According to the negatively shifted valence band values, the device efficiency can be improved by improving electron injection due to a decrease in the band-offset between the quantum dot and the electron transport layer. In addition, Examples 1 and 2 can include 10 at% or more of organic ligands compared to Comparative Example 2. According to this, the organic ligand is stably bound to the quantum dot surface, and when manufacturing an ink including a quantum dot complex, the discharge stability can be improved through organic substance precipitation control.

[0137] Meanwhile, when the purification process was performed with ethanol containing ZnCl2 according to the manufacturing process according to one embodiment, it was confirmed that the Cl contained in the quantum dot complex was contained at about 6.89 at%. In addition, when the purification process was performed with ethanol containing ZnBr2 according to the manufacturing process according to one embodiment, it was confirmed that the Br contained in the quantum dot complex was contained at about 2.96 at%. In addition, when the purification process was performed with ethanol containing ZnI2 according to the manufacturing process according to one embodiment, it was confirmed that the I contained in the quantum dot complex was contained at about 1.86 at%.

[0138] It was confirmed that a quantum dot complex manufactured by a manufacturing process according to one embodiment can provide a plurality of ligands stably bonded to a bonding portion, thereby providing a quantum dot with improved luminescence efficiency.

[0139] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

Claims

1. Quantum dots; and Containing a ligand that binds to the surface of the quantum dot, A plurality of binding sites to which the ligand binds are provided on the surface of the quantum dot, The above-mentioned coupling part comprises a first coupling part and a second coupling part, The above ligands are, A first ligand bound to the first binding portion, and comprising a second ligand bound to the second binding portion; The second ligand comprises a halogen element, A quantum dot complex wherein the above halogen element is included in an amount of 1 at% to 12 at% relative to the content of the entire quantum dot complex.

2. In paragraph 1, The above halogen element is one of chlorine, fluorine, iodine and bromine, When the above halogen element is chlorine, the chlorine is included in an amount of 5 at% to 7 at% relative to the total content of the quantum dot complex, When the above halogen element is bromine, the bromine is included in an amount of 2 at% to 4 at% relative to the total content of the quantum dot complex, When the above halogen element is iodine, the iodine is included in an amount of 1 at% to 2 at% relative to the total content of the quantum dot complex, A quantum dot complex wherein, when the halogen element is fluorine, the fluorine is contained in an amount of 9 at% to 12 at% relative to the total content of the quantum dot complex.

3. In paragraph 1, The above quantum dot complex is a quantum dot complex having an organic matter content of 10 at% or more relative to the content of the entire quantum dot complex.

4. In paragraph 1, The above quantum dot complex emits red light, A quantum dot complex having a valence band value of -5.60 eV to -5.80 eV.

5. In paragraph 1, The above quantum dot complex emits green light, A quantum dot complex having a valence band value of -5.73 eV to -5.93 eV.

6. In paragraph 1, The above quantum dot complex emits blue light, A quantum dot complex having a valence band value of -5.78 eV to -5.98 eV.

7. In paragraph 1, The above-mentioned connecting portion further includes a third connecting portion, A quantum dot complex wherein the ligand further comprises a third ligand bound to the second binding portion or the third binding portion.

8. In paragraph 7, A quantum dot complex wherein the third ligand comprises one selected from phosphine and phosphine oxide.

9. In paragraph 8, A quantum dot complex wherein the third ligand further comprises 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 thiol group, a substituted or unsubstituted oxy group, a substituted or unsubstituted aryl group having 6 to 30 ring-forming carbon atoms, or a substituted or unsubstituted heteroaryl group having 2 to 30 ring-forming carbon atoms.

10. In paragraph 1, The quantum dot is a quantum dot complex comprising a core and a shell surrounding the core.

11. In Article 10, The above bonding portion is a quantum dot complex provided on the surface of the shell.

12. In Article 10, A quantum dot complex wherein the core comprises a first semiconductor nanocrystal, the shell comprises 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 a group II-VI compound, a group III-V compound, a group IV-VI compound, a group IV element, a group IV compound, and a combination thereof.

13. First electrode, A light-emitting layer positioned on the first electrode, and Including a second electrode positioned on the above light-emitting layer, The above light-emitting layer comprises a quantum dot complex, The above quantum dot complex is, Quantum dots; and Containing a ligand that binds to the surface of the quantum dot, A plurality of binding sites to which the ligand binds are provided on the surface of the quantum dot, The above-mentioned coupling part comprises a first coupling part and a second coupling part, The above ligands are, A first ligand bound to the first binding portion, and comprising a second ligand bound to the second binding portion; The above quantum dot complex contains a halogen element, An indicator device in which the above halogen element is included in an amount of 1 at% to 12 at% of the total content.

14. In paragraph 13, The above halogen element is one of chlorine, fluorine, iodine and bromine, When the above halogen element is chlorine, the chlorine is included in an amount of 5 at% to 7 at% relative to the total content of the quantum dot complex, When the above halogen element is bromine, the bromine is included in an amount of 2 at% to 4 at% relative to the total content of the quantum dot complex, When the above halogen element is iodine, the iodine is included in an amount of 1 at% to 2 at% relative to the total content of the quantum dot complex, A display device wherein, when the halogen element is fluorine, the fluorine is contained in an amount of 9 at% to 12 at% relative to the total content of the quantum dot complex.

15. In paragraph 13, The above quantum dot complex is a display device having an organic matter content of 10 at% or more relative to the content of the entire quantum dot complex.

16. In paragraph 13, 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. A display device wherein the quantum dot complex has a valence band value of -5.78 eV to -5.98 eV when the quantum dot complex emits blue light.

17. A step of providing a quantum dot complex having a first ligand bound to the quantum dot surface, and Comprising a step of mixing the above quantum dot complex into a first solution and purifying it, The above first solution contains MX, In the above 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. In the step of mixing the above quantum dot complex into the first solution and purifying it, A method for producing a quantum dot complex, wherein a second ligand is bound to the surface of the quantum dot, and the second ligand includes X.

18. In Article 17, The above first solution contains a polar solvent, A method for producing a quantum dot complex, wherein the polar solvent comprises methanol, ethanol, phenol, benzenediol, ethylene glycol, glycerol, diethylene glycol, triethylene glycol, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether or a combination thereof.

19. In Article 17, A method for producing a quantum dot complex, wherein the above MX is provided at a concentration of 0.1 M to 0.5 M.

20. In Article 17, Before the step of mixing the above quantum dot complex into the first solution and purifying it, A method for producing a quantum dot complex further comprising a surface treatment step for binding a third ligand to the surface of the quantum dot.

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