Color conversion panel, population of luminescent nanostructures and ink composition

Abstract

A color conversion panel, a group of luminescent nanostructures, and an ink composition are provided. The color conversion panel includes a color conversion layer comprising two or more color conversion regions and optionally partitions defining the regions of the color conversion layer. Each color conversion region includes a first region corresponding to a green pixel, the first region comprising a first composite configured to emit green light and containing a matrix and a plurality of luminescent nanostructures dispersed within the matrix. The luminescent nanostructures include a first semiconductor nanocrystal comprising a group III-V compound and a second semiconductor nanocrystal comprising a zinc chalcogenide, the group III-V compound including indium, phosphorus, and optionally zinc, and the zinc chalcogenide including zinc, selenium, and sulfur. The luminescent nanostructures do not include cadmium, and at least a portion of the surface of the luminescent nanostructures comprises the second semiconductor nanocrystal. The emitted green light has a full width at half maximum (FWHM) of less than or equal to about 42 nm.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2021-0029746, filed on March 5, 2021, with the Korean Intellectual Property Office, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] A light-emitting nanostructure, a method for manufacturing the light-emitting nanostructure, and a color conversion panel and electronic device (e.g., a display panel) including the light-emitting nanostructure are disclosed. Background Technology

[0003] Compared to their bulk counterparts with essentially the same composition, nanostructures can exhibit different aspects, characteristics, or properties, for example, in some of their physical properties (e.g., band gap energy, luminescence properties, etc.), which are known as the inherent properties of the bulk material. Luminescent nanostructures can be configured to emit light when excited by energy such as incident light or an applied voltage. Luminescent nanostructures can find applicability in a variety of devices, such as display panels or electronic devices that include display panels. There is a strong interest in developing luminescent nanostructures that do not contain toxic heavy metals (such as cadmium) but still exhibit similar or even improved luminescent properties or performance. Summary of the Invention

[0004] The embodiment provides a color conversion panel including a light-emitting nanostructure that can exhibit improved optical properties (e.g., luminous efficiency, incident light absorption, etc.) and enhanced (chemical and / or thermal) stability.

[0005] The embodiments provide a method for fabricating luminescent nanostructures.

[0006] The embodiments provide a group of light-emitting nanostructures or an ink composition containing light-emitting nanostructures.

[0007] The embodiments provide an electronic device (e.g., a display device) including a light-emitting nanostructure or a color conversion panel.

[0008] In one embodiment, a color conversion panel includes a color conversion layer, the color conversion layer including color conversion regions and optionally partitions defining each region of the color conversion layer, the color conversion regions including a first region corresponding to a green pixel, and the first region including a first composite, the first composite being configured to emit green light and including a matrix and a plurality of luminescent nanostructures dispersed in the matrix.

[0009] The luminescent nanostructure comprises a first semiconductor nanocrystal containing a group III-V compound and a second semiconductor nanocrystal containing a zinc chalcogenide. The group III-V compound includes indium, phosphorus, and optionally zinc, and the zinc chalcogenide includes zinc, selenium, and sulfur. The luminescent nanostructure does not include cadmium.

[0010] In this embodiment, at least a portion of the surface of the luminescent nanostructure comprises a second semiconductor nanocrystal, and

[0011] The full width at half maximum (FWHM) of the maximum emission peak of the green light (or luminescent nanostructure) is less than or equal to about 42 nm (e.g., less than or equal to about 41 nm, less than or equal to about 40 nm, or less than or equal to about 39 nm).

[0012] The maximum emission peak of green light (or luminescent nanostructures) can be greater than or equal to about 500 nm or greater than or equal to about 505 nm. The maximum emission peak of green light (or luminescent nanostructures) can be less than or equal to about 530 nm, less than or equal to about 525 nm, less than or equal to about 520 nm, less than or equal to about 515 nm, or less than or equal to about 510 nm.

[0013] Luminescent nanostructures can exhibit a UV-Vis absorption spectrum with a positive differential coefficient (i.e., tangential slope) at 450 nm.

[0014] The differential coefficient can be greater than zero or greater than or equal to approximately 0.001.

[0015] In the UV-Vis absorption spectrum of the luminescent nanostructure, the ratio of absorbance at the first absorption peak wavelength to absorbance at a wavelength of about 350 nm can be greater than or equal to about 0.2:1 or greater than or equal to about 0.23:1.

[0016] In the UV-Vis absorption spectrum of luminescent nanostructures, the valley depth (VD) defined by the following equation can be greater than or equal to about 0.2, greater than or equal to about 0.3, greater than or equal to about 0.35, or greater than or equal to about 0.4:

[0017] 1-(Abs 谷 / Abs 第一 ) = VD

[0018] Among them, Abs 第一 The absorption rate corresponding to the first absorption peak, Abs 谷 The absorption rate corresponds to the lowest point of the valley adjacent to the first absorption peak.

[0019] In luminescent nanostructures, the molar ratio of sulfur to selenium can be greater than or equal to about 0.3:1 or greater than or equal to about 0.5:1. Luminescent nanostructures can include molar ratios of sulfur to selenium greater than or equal to about 1.9:1, greater than or equal to about 2:1, greater than or equal to about 2.01:1, greater than or equal to about 2.1:1, greater than or equal to about 2.3:1, greater than or equal to about 2.4:1, greater than or equal to about 2.5:1, greater than or equal to about 2.6:1, greater than or equal to about 3:1, greater than or equal to about 3.5:1, or greater than or equal to about 4:1.

[0020] In luminescent nanostructures, the molar ratio of sulfur to selenium can be less than or equal to approximately 15:1, less than or equal to approximately 14.5:1, less than or equal to approximately 14.2:1, less than or equal to approximately 14:1, less than or equal to approximately 13:1, less than or equal to approximately 12:1, less than or equal to approximately 11:1, less than or equal to approximately 10:1, less than or equal to approximately 8:1, less than or equal to approximately 6:1, less than or equal to approximately 5.5:1, less than or equal to approximately 5:1, less than or equal to approximately 4.5:1, less than or equal to approximately 4:1, less than or equal to approximately 3.5:1, less than or equal to approximately 3:1, less than or equal to approximately 2.8:1, less than or equal to approximately 2.7:1, less than or equal to approximately 2.67:1, or less than or equal to approximately 2.66:1.

[0021] In luminescent nanostructures, the molar ratio of selenium to sulfur can be greater than or equal to about 0.07:1 and less than or equal to about 3.35:1.

[0022] In luminescent nanostructures, the molar ratio of sulfur to indium can be greater than or equal to approximately 3:1, greater than or equal to approximately 5:1, greater than or equal to approximately 7:1, greater than or equal to approximately 9:1, or greater than or equal to approximately 9.4:1. In luminescent nanostructures, the molar ratio of sulfur to indium can be less than or equal to approximately 20:1, less than or equal to approximately 17:1, less than or equal to approximately 15:1, less than or equal to approximately 13:1, less than or equal to approximately 12:1, or less than or equal to approximately 11.5:1.

[0023] In luminescent nanostructures, the molar ratio of selenium to indium can be less than or equal to approximately 10:1, less than or equal to approximately 8:1, less than or equal to approximately 6:1, less than or equal to approximately 5:1, or less than or equal to approximately 4.8:1. The molar ratio of selenium to indium can be greater than or equal to approximately 1:1, greater than or equal to approximately 2:1, greater than or equal to approximately 3:1, greater than or equal to approximately 3.5:1, greater than or equal to approximately 4:1, or greater than or equal to approximately 4.3:1.

[0024] In luminescent nanostructures, the molar ratio of zinc to indium can be less than or equal to approximately 30:1, less than or equal to approximately 24:1, less than or equal to approximately 23:1, less than or equal to approximately 22:1, less than or equal to approximately 21:1, less than or equal to approximately 20:1, less than or equal to approximately 19:1, less than or equal to approximately 18:1, or less than or equal to approximately 17:1. The molar ratio of zinc to indium can be greater than or equal to approximately 5:1, greater than or equal to approximately 10:1, greater than or equal to approximately 15:1, or greater than or equal to approximately 17:1.

[0025] In luminescent nanostructures, the molar ratio of phosphorus to indium can be greater than or equal to approximately 0.7:1, greater than or equal to approximately 0.75:1, greater than or equal to approximately 0.8:1, greater than or equal to approximately 0.85:1, greater than or equal to approximately 0.88:1, greater than or equal to approximately 0.89:1, greater than or equal to approximately 0.9:1, greater than or equal to approximately 0.93:1, or greater than or equal to approximately 0.95:1. In luminescent nanostructures, the molar ratio of phosphorus to indium can be less than or equal to approximately 1.5:1, less than or equal to approximately 1.4:1, less than or equal to approximately 1.3:1, less than or equal to approximately 1.2:1, less than or equal to approximately 1.1:1, less than or equal to approximately 1.05:1, less than or equal to approximately 1:1, or less than or equal to approximately 0.95:1.

[0026] The luminescent nanostructure can be mixed with a predetermined amount of benzyl viologen to determine the relative reduction (or loss) in the photoluminescence efficiency of the luminescent nanostructure. The reduction in photoluminescence efficiency of the luminescent nanostructure can be less than or equal to about 15%, less than or equal to about 13%, less than or equal to about 11%, or less than or equal to about 10%. The predetermined amount of benzyl viologen (e.g., experimentally added benzyl viologen) can be less than or equal to about 130 μL or less than or equal to about 100 μL at a concentration of 0.2 mmol (mM). Mixing can be performed using a dispersion prepared by dispersing 500 μg of the luminescent nanostructure in 3 mL of toluene (e.g., see Examples section).

[0027] The first composite can be prepared by heat treatment at a temperature of about 180°C for a period of time (e.g., about 30 minutes), and the first composite can exist in the form of a film having a thickness of about 6 μm (e.g., 10 μm or more). In the first composite, the amount of luminescent nanostructures can be less than or equal to about 45 weight percent (wt%) (e.g., about 43 wt%) based on the total weight of the first composite.

[0028] The first composite may exhibit a light conversion efficiency (or light conversion effectiveness) greater than or equal to about 33%, greater than or equal to about 34%, greater than or equal to about 35%, greater than or equal to about 36%, or greater than or equal to about 37%, and a light conversion effectiveness greater than or equal to about 37%, greater than or equal to about 38%, greater than or equal to about 39%, greater than or equal to about 40%, greater than or equal to about 41%, or greater than or equal to about 42%, and the light conversion efficiency and light conversion effectiveness are defined by the following equations:

[0029] (A / B)×100=Light conversion efficiency (%)

[0030] [A / (B-B')]×100=Light conversion efficiency (%)

[0031] A: Light dose of green light emitted from the first complex

[0032] B: Light dose of the incident light (e.g., blue light with wavelengths of about 450 nm to about 470 nm or about 458 nm to about 460 nm).

[0033] B': The light dose that has passed through the first complex.

[0034] The first composite or a film comprising the first composite may have an incident light absorption rate greater than or equal to about 80%, greater than or equal to about 82%, greater than or equal to about 84%, greater than or equal to about 84.5%, or greater than or equal to about 85%.

[0035] (B-B') / B×100=Incident light absorptivity (%)

[0036] B and B' are the same as defined above.

[0037] The maximum emission peak wavelength of the incident light can be in the range of about 450 nm, about 460 nm, and about 470 nm (e.g., about 458 nm).

[0038] When irradiated with incident light at wavelengths of about 450 nm to about 460 nm, the first complex may exhibit a loss percentage (hereinafter, QY loss) of less than about 14%, less than or equal to about 13%, less than or equal to about 12%, less than or equal to about 11%, or less than or equal to about 10% of the quantum yield (QY) at room temperature (e.g., 20 °C to 30 °C) compared to the luminescence efficiency (QY) at about 80 °C:

[0039] QY loss = [1 - (QY at 80℃ / QY at room temperature)] × 100 (%).

[0040] When the first complex is irradiated with incident light (e.g., blue light having a wavelength of about 450 nm to about 470 nm or about 458 nm to about 460 nm), the tailing percentage of the first complex, as defined by the following equation, may be less than or equal to about 15%:

[0041] Tail percentage (%) = [S2 / S1] × 100, where,

[0042] S1: Total area of ​​the maximum photoluminescence peak of the first complex (or green light)

[0043] S2: The area of ​​the maximum photoluminescence peak of the first complex (or green light) in the wavelength region greater than or equal to about 580 nm.

[0044] The average size of the first semiconductor nanocrystal can be greater than or equal to about 1.5 nanometers (nm) and / or less than or equal to about 2.5 nm.

[0045] The quantum efficiency (e.g., absolute quantum yield) of the luminescent nanostructure can be greater than or equal to about 80%, greater than or equal to about 81%, greater than or equal to about 82%, greater than or equal to about 83%, greater than or equal to about 84%, greater than or equal to about 85%, or greater than or equal to about 90%.

[0046] Multiple luminescent nanostructures can have a core-shell structure comprising a core and a shell disposed on the core. The core may comprise a first semiconductor nanocrystal, and the shell may comprise a second semiconductor nanocrystal.

[0047] The second semiconductor nanocrystal or shell may have a thickness of less than or equal to about 6 monolayers. The thickness of the second semiconductor nanocrystal or shell may be less than or equal to about 2 nm, less than or equal to about 1.6 nm, less than or equal to about 1.55 nm, or less than or equal to about 1.5 nm.

[0048] The luminescent nanostructures can have an average size of less than or equal to about 6 nm, or less than or equal to about 5 nm and greater than or equal to about 2 nm, or greater than or equal to about 3 nm, and the size distribution of the luminescent nanostructures can be less than or equal to about 30% of the average size.

[0049] In an embodiment, the shell may be a multilayer shell comprising at least two shell layers, wherein adjacent shell layers may have different compositions from each other. The multilayer shell may include, for example, a first shell layer comprising zinc, selenium, and optionally sulfur disposed on a core, and a second shell layer disposed on the first shell layer, the second shell layer comprising zinc, sulfur, and optionally selenium, wherein the composition of the first semiconductor nanocrystal may differ from the composition of the second semiconductor nanocrystal.

[0050] Compared to the first shell, the second shell may include a larger amount (e.g., molar) of sulfur. The first shell may include ZnSe, ZnS, ZnSeS, or combinations thereof. The second shell may include ZnSe, ZnS, ZnSeS, or combinations thereof. The first shell may be disposed on a semiconductor nanocrystal core (e.g., directly disposed on a semiconductor nanocrystal core). The second shell may be disposed on the first shell (e.g., directly disposed on the first shell). The second shell may be the outermost layer of a light-emitting nanostructure.

[0051] The first shell may have a thickness of less than or equal to about 1 nm, less than or equal to about 0.9 nm, less than or equal to about 0.8 nm, less than or equal to about 0.7 nm, or less than or equal to about 0.6 nm. The first shell may have a thickness of greater than or equal to about 0.3 nm, greater than or equal to about 0.4 nm, or greater than or equal to about 0.5 nm.

[0052] The second shell may have a thickness of less than or equal to about 1 nm, less than or equal to about 0.9 nm, less than or equal to about 0.8 nm, less than or equal to about 0.7 nm, or less than or equal to about 0.6 nm. The first shell may have a thickness of greater than or equal to about 0.3 nm, greater than or equal to about 0.4 nm, or greater than or equal to about 0.5 nm.

[0053] As a dispersion in an organic solvent, the luminescent nanostructure can emit light with a maximum emission peak having a full width at half maximum (FWHM) of about 40 nm, about 43 nm, about 45 nm, or about 46 nm. As a dispersion in an organic solvent, the luminescent nanostructure can emit light with a maximum emission peak having a FWHM of about 55 nm, about 53 nm, about 51 nm, about 50 nm, about 49 nm, or about 48 nm.

[0054] For example, as measured by electron microscopy, luminescent nanostructures can have an average particle size of less than or equal to about 6.5 nm, less than or equal to about 6 nm, less than or equal to about 5.5 nm, or less than or equal to about 5 nm.

[0055] At the surface of the luminescent nanostructure, the molar ratio of selenium to the sum of selenium and sulfur can be greater than 0, greater than or equal to about 0.001:1, greater than or equal to about 0.01:1 and less than or equal to about 0.3:1, or less than or equal to about 0.2:1.

[0056] The embodiments relate to a group including the luminescent nanostructures described herein.

[0057] In embodiments, the group including luminescent nanostructures may include first semiconductor nanocrystals comprising group III-V compounds and second semiconductor nanocrystals comprising zinc chalcogenides, wherein the group III-V compounds include indium, phosphorus, and optionally zinc, and the zinc chalcogenides include zinc, selenium, and sulfur, and the luminescent nanostructures do not include cadmium.

[0058] In this embodiment, at least a portion of the surface of each of the luminescent nanostructures comprises a second semiconductor nanocrystal, and

[0059] Among them, the luminescent nanostructures were configured to emit green light.

[0060] The UV-Vis absorption spectrum of the luminescent nanostructure has a positive differential coefficient (i.e., tangential slope) at 450 nm. In the UV-Vis absorption spectrum of the luminescent nanostructure, the ratio of absorbance at the first absorption peak wavelength to absorbance at a wavelength of about 350 nm (i.e., absorbance ratio) is greater than or equal to about 0.2:1.

[0061] In the embodiments, at the surface of the luminescent nanostructure, the molar ratio of selenium to the sum of selenium and sulfur can be greater than 0, greater than or equal to about 0.1, greater than or equal to about 0.15, greater than or equal to about 0.2 and less than or equal to about 0.5:1, less than or equal to about 0.3:1, or less than or equal to about 0.25:1.

[0062] The polymer matrix may include linear polymers, cross-linked polymers, or combinations thereof.

[0063] Crosslinked polymers may include thiolene resins, crosslinked poly(meth)acrylates, crosslinked polyurethanes, crosslinked epoxy resins, crosslinked vinyl polymers, crosslinked silicone resins, or combinations thereof.

[0064] Linear polymers may include repeating units derived from carbon-carbon unsaturated bonds (e.g., carbon-carbon double bonds). Repeating units may include carboxylic acid groups. Linear polymers may include ethylene repeating units.

[0065] Repeating units containing a carboxylic acid group may include units derived from monomers comprising a carboxylic acid group and a carbon-carbon double bond, units derived from monomers having a dianhydride moiety, or combinations thereof.

[0066] The polymer matrix may include compounds containing carboxylic acid groups (e.g., adhesives, adhesive polymers, or dispersants) (e.g., for dispersing quantum dots or as an adhesive).

[0067] Compounds containing carboxylic acid groups may include:

[0068] Monomer compositions comprising a first monomer containing a carboxylic acid group and a carbon-carbon double bond, a second monomer having a carbon-carbon double bond and a hydrophobic portion, and optionally a third monomer containing a carbon-carbon double bond and a hydrophilic portion but not containing a carboxylic acid group, or copolymers thereof, wherein the second monomer does not contain a carboxylic acid group;

[0069] Polycyclic aromatic polymers having a main chain structure including a carboxylic acid group (-COOH), wherein two aromatic rings are bonded to a quaternary carbon atom that is a constituent atom of another cyclic part in the main chain;

[0070] Or a combination of them.

[0071] The (polymer) matrix may also include the polymeric product of a monomeric composition, an alkene compound having carbon-carbon unsaturated bonds, fine particles of metal oxides, or combinations thereof, wherein the monomeric composition includes a (polyfunctional or monofunctional) thiol compound (e.g., a mono- or poly-thiol compound) having at least one thiol group at the end.

[0072] The first complex can be in the form of a patterned film.

[0073] The embodiments also include a group of multiple luminescent nanostructures described herein.

[0074] In an embodiment, an ink composition includes a liquid carrier and a group of multiple luminescent nanostructures described herein.

[0075] Multiple luminescent nanostructures can be dispersed in a liquid carrier.

[0076] Liquid carriers may include liquid monomers, organic solvents, or combinations thereof.

[0077] The ink composition or the first complex may also include fine particles of metal oxide.

[0078] The ink composition may also include a dispersant, fine metal oxide particles, or a combination thereof for dispersing the luminescent nanostructures.

[0079] In one embodiment, a display panel includes a light-emitting panel (or light source), a color conversion panel described herein, and a light-transmitting layer disposed between the light-emitting panel and the color conversion panel.

[0080] The light-emitting panel (or light source) can be configured to provide incident light to the color conversion panel. The incident light may include blue light and optionally green light. The blue light may have an emission peak wavelength in the range of about 440 nm to about 460 nm or about 450 nm to about 455 nm.

[0081] In an embodiment, the electronic device (or display device) may include a color conversion panel or a display panel.

[0082] The luminescent nanostructures of the embodiments can exhibit improved optical properties (e.g., improved blue light absorption and luminescence efficiency) and enhanced (chemical and / or thermal) stability. The luminescent nanostructures of the embodiments can be configured to emit light with improved efficiency (e.g., green light) even when included in the form of a composite. The luminescent nanostructures of the embodiments can address the related problem of luminescence efficiency decreasing with device operating time.

[0083] In the embodiments, the color conversion panel can be used with a variety of light sources and can be used in liquid crystal display devices, QD-OLED devices, QD microLED display devices including QD color filters and (blue) microLEDs, etc. The light-emitting nanostructures and color conversion panels of the embodiments can be used in many devices, such as televisions, monitors, mobile devices, virtual reality or augmented reality devices, automotive display applications, etc. Attached Figure Description

[0084] These and / or other aspects will become apparent and more readily understood from the following description of embodiments, taken in conjunction with the accompanying drawings, in which:

[0085] Figure 1A This is a schematic cross-sectional view of the color conversion panel according to an embodiment;

[0086] Figure 1B This is a schematic cross-sectional view of the luminescent nanostructure of the embodiment;

[0087] Figure 1C The UV-Vis absorption spectrum of the luminescent nanostructure in the embodiment is shown.

[0088] Figure 2A A process for fabricating luminescent nanostructure composite patterns using compositions according to embodiments is shown;

[0089] Figure 2B A process for fabricating luminescent nanostructure composite patterns using compositions according to embodiments is shown;

[0090] Figure 3A This is a perspective view illustrating an example of a display panel of an embodiment;

[0091] Figure 3B This is an exploded view of the display device of the embodiment;

[0092] Figure 4 yes Figure 3A A cross-sectional view of the display panel;

[0093] Figure 5 This shows the display panel (e.g., as shown in the image). Figure 3A A plan view of an example of pixel arrangement (as shown in the image);

[0094] Figure 6A It is along line IV-IV of the display panel in the embodiment (e.g. Figure 5 The sectional view shown in the image;

[0095] Figure 6B This is a cross-sectional view of the display panel according to an embodiment;

[0096] Figure 7 It is a cross-sectional view of a display device (e.g., a liquid crystal display device) according to an embodiment; and

[0097] Figure 8 This is a view showing the results of Experiment Example 1 described here. Detailed Implementation

[0098] The advantages and features of this disclosure and its implementation methods will become apparent from the following exemplary embodiments and the accompanying drawings. However, the embodiments should not be construed as limiting to those set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. The same reference numerals throughout refer to the same elements.

[0099] Unless otherwise defined, all terms in this specification (including technical and scientific terms) may be defined as commonly understood by those skilled in the art. It will also be understood that terms (such as those defined in common dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant field and in this disclosure, and should not be interpreted in an idealized or overly formal sense, unless expressly so stated herein.

[0100] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to include the plural forms that include “at least one.” “At least one” will not be construed as limited to “a” or “an.” “Or” means “and / or.” As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Additionally, unless explicitly stated otherwise, the word “comprising” and variations such as “including” or “containing” will be understood to mean including the stated elements, but not excluding any other elements. It will also be understood that when the terms “comprising” and / or “including” and variations thereof are used in this specification, they indicate the presence of the stated features, areas, integrals, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, areas, integrals, steps, operations, elements, components, and / or groups thereof. In the accompanying drawings, the thickness of layers, films, panels, areas, etc., is exaggerated for clarity. Throughout the specification, the same reference numerals denote the same elements.

[0101] It will be understood that when an element, such as a layer, film, region, or substrate, is referred to as being "on" another element, the element may be directly on the other element, or there may be intermediate elements present. Conversely, when an element is referred to as being "directly on" another element, there are no intermediate elements present.

[0102] Furthermore, relative terms such as “below” or “bottom” and “above” or “top” may be used here to describe the relationship between one element and another as shown in the accompanying drawings. It will be understood that relative terms are intended to cover different orientations of the device other than those depicted in the drawings. For example, if the device in a drawing is flipped, an element described as being “below” the other element will subsequently be positioned “above” the other element. Thus, depending on the specific orientation in the drawing, the exemplary term “below” can include both “below” and “above” orientations. Similarly, if the device in a drawing is flipped, an element described as being “below” or “under” the other element will subsequently be positioned “above” the other element. Thus, the exemplary terms “below” or “under” can include both “above” and “below” orientations.

[0103] Taking into account the measurements discussed and the errors associated with the measurement of a particular quantity (i.e., the limitations of the measurement system), as used herein, “about” includes the stated value and indicates an acceptable deviation from the particular value as determined by one of ordinary skill in the art. For example, “about” may mean within one or more standard deviations, or within ±10% or ±5% of the stated value.

[0104] It will be understood that while the terms “first,” “second,” “third,” etc., may be used herein to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or part from another. Therefore, without departing from the teaching herein, the first “element,” “component,” “region,” “layer,” or “part” discussed below may be designated as a second element, component, region, layer, or part.

[0105] Exemplary embodiments are described herein with reference to cross-sectional views, which are schematic representations of idealized embodiments. Thus, variations in the shapes illustrated will be expected, for example, due to manufacturing techniques and / or tolerances. Therefore, the embodiments described herein should not be construed as limited to the specific shapes of the regions shown herein, but will include, for example, deviations in shape due to manufacturing processes. For example, regions shown or described as flat may generally have rough and / or non-linear characteristics. Furthermore, acute angles shown may be rounded. Therefore, the regions shown in the figures are schematic in nature, and their shapes are not intended to show the precise shapes of the regions and are not intended to limit the scope of the given claims.

[0106] As used herein, the expression "excluding cadmium (or other harmful heavy metals)" can mean that the concentration of cadmium (or other harmful heavy metals) is less than or equal to about 100 parts per million (ppmw), less than or equal to about 50 ppmw, less than or equal to about 10 ppmw, less than or equal to about 1 ppmw, less than or equal to about 0.1 ppmw, less than or equal to about 0.01 ppmw, or about zero. In embodiments, a certain amount of cadmium (or other harmful heavy metals) may be substantially absent, or if present, the amount of cadmium (or other harmful heavy metals) may be less than or equal to the detection limit or the impurity level of a given analytical tool (e.g., inductively coupled plasma atomic emission spectrometry).

[0107] As used herein, unless otherwise defined, the term “substituted” refers to a compound or group or part in which at least one hydrogen atom of the compound or group or part is substituted by a substituent. Substituents may include C1 to C30 alkyl, C2 to C30 alkenyl, C2 to C30 alkynyl, C6 to C30 aryl, C7 to C30 alkylaryl, C1 to C30 alkoxy, C1 to C30 heteroalkyl, C3 to C40 heteroaryl, C3 to C30 heteroalkylaryl, C3 to C30 cycloalkyl, C3 to C15 cycloalkenyl, C6 to C30 cycloalkynyl, C2 to C30 heterocycloalkyl, halogen (-F, -Cl, -Br or -I), hydroxyl (-OH), nitro (-NO2), cyano (-CN), amino or amino (-NRR', where R and R' are the same or different, and both are independently hydrogen or C1 to C6 alkyl), azide (-N3), amidine (-C (=NH)NH2), hydrazine (-NHNH2), hydrazone (=N(NH2)), aldehyde (-C(=O)H), carbamoyl (-C(O)NH2), thiol (-SH), ester (-C(=O)OR, wherein R is a C1 to C6 alkyl or a C6 to C12 aryl), carboxylic acid (-COOH) or its salt (-C(=O)OM, wherein M is an organic or inorganic cation), sulfonic acid (-SO3H) or its salt (-SO3M, wherein M is an organic or inorganic cation), phosphate (-PO3H2) or its salt (-PO3MH or -PO3M2, wherein M is an organic or inorganic cation) or combinations thereof.

[0108] As used herein, unless otherwise defined, the term "heterogeneous" means a compound, group, or substituent comprising at least one heteroatom (e.g., one to three heteroatoms), wherein each heteroatom is independently N, O, S, Si, P, or a combination thereof.

[0109] As used herein, unless otherwise defined, the term "aliphatic hydrocarbon group" refers to a C1 to C30 straight-chain or branched alkyl group, a C2 to C30 straight-chain or branched alkenyl group, or a C2 to C30 straight-chain or branched alkynyl group.

[0110] As used herein, unless otherwise defined, the term "aromatic" or "aromatic hydrocarbon group" refers to a portion having at least one aromatic ring and optionally forming one or more non-aromatic rings by removing one or more hydrogen atoms from one or more rings of an aromatic hydrocarbon, wherein the hydrogen atoms may be removed from the aromatic ring or the non-aromatic ring (if present). One or more heteroatoms (e.g., N, P, S, O, Si, or combinations thereof) may be present in one or more rings. The aromatic hydrocarbon group may optionally be substituted by one or more substituents.

[0111] As used herein, unless otherwise defined, the term "aryl" refers to a group comprising one to five aromatic rings, having a single valence, and formed by removing a hydrogen atom from one ring. "Heteroaryl" refers to an aryl group in which at least one carbon atom of an aromatic ring is replaced by a heteroatom (e.g., N, P, S, O, Si, or combinations thereof). Aryl and heteroaryl groups may optionally be substituted with one or more substituents. Aryl groups can be C6 to C30 aryl groups, and heteroaryl groups can be C2 to C30 heteroaryl groups.

[0112] As used herein, unless otherwise defined, "(meth)acrylate" means acrylate, methacrylate, or a combination thereof. (Meth)acrylate may include (C1 to C10 alkyl)acrylate, (C1 to C10 alkyl)methacrylate, or a combination thereof.

[0113] As used here, the term "family" can refer to a family of elements in the periodic table.

[0114] As used here, “Group III” refers to Group IIIA and Group IIIB, and examples of Group III metals can be Al, In, Ga, and Tl, but are not limited to these.

[0115] As used herein, “group V” can refer to group VA, and examples of it can include, but are not limited to, nitrogen, phosphorus, arsenic, antimony and bismuth.

[0116] As used herein, a nanostructure is a structure having at least one region or feature size having a size less than or equal to about 500 nm. In embodiments, the size (or average value) of the nanostructure is less than or equal to about 300 nm, less than or equal to about 250 nm, less than or equal to about 150 nm, less than or equal to about 100 nm, less than or equal to about 50 nm, or less than or equal to about 30 nm. In embodiments, the structure can have any shape. Nanostructures can include, but are not limited to, nanowires, nanorods, nanotubes, branched nanostructures, nanonotetrapods, nanotripods, nanobipods, nanocrystals, nanodots, multi-pod shapes (such as at least two needles), etc. Nanostructures can be, for example, substantially crystalline, substantially single-crystal, polycrystalline, (e.g., at least partially) amorphous, or combinations thereof.

[0117] As used herein, the term "quantum dot" refers to a nanostructure (e.g., a semiconductor-based nanocrystal particle exhibiting quantum confinement or exciton confinement). A quantum dot is a type of luminescent nanostructure (e.g., capable of emitting light upon energy excitation). As used herein, unless otherwise defined, the shape of a "quantum dot" may not be particularly limited.

[0118] In embodiments, "dispersion" can refer to a system in which the dispersed phase is a solid and the continuous phase includes a liquid or a solid different from the dispersed phase. In embodiments, "dispersion" refers to a system in which the dispersed phase has a size greater than or equal to about 1 nm (e.g., greater than or equal to about 2 nm, greater than or equal to about 3 nm, or greater than or equal to about 4 nm) and a few micrometers (μm) or smaller (e.g., less than or equal to about 2 μm, less than or equal to about 1 μm, less than or equal to about 900 nm, less than or equal to about 800 nm, less than or equal to about 700 nm, less than or equal to about 600 nm, or less than or equal to about 500 nm).

[0119] As used herein, the term "average" (e.g., the average size of a quantum dot) can be an average or a median. In embodiments, average can be the "average" average.

[0120] In embodiments, quantum efficiency (which may be used interchangeably with the term "quantum yield" (QY)) can be measured in either the solution state or the solid state (in the complex). In embodiments, quantum efficiency can be, for example, the ratio of photons emitted by a nanostructure or group of nanostructures to the photons absorbed. In embodiments, quantum efficiency can be determined by any suitable method. For example, there are two methods for measuring fluorescence quantum yield or efficiency: absolute methods and relative methods. Absolute methods directly obtain quantum yield by detecting the fluorescence of all samples using an integrating sphere. In relative methods, the fluorescence intensity of a standard sample (e.g., a standard dye) can be compared with the fluorescence intensity of an unknown sample to calculate the quantum yield of the unknown sample. Coumarin 153, coumarin 545, rhodamine 101 inner salt, anthracene, and rhodamine 6G can be used as standard dyes, but are not limited to, depending on the photoluminescence (PL) wavelength.

[0121] Quantum yield (i.e., luminous efficiency) can be easily and reproducibly determined using commercially available equipment (e.g., equipment from Hitachi Co. Ltd. or Hamamatsu Co. Ltd.) and with reference to the manufacturer’s instruction manual.

[0122] The full width at half maximum (FWHM) and the maximum photoluminescence (PL) peak wavelength can be determined by the photoluminescence spectrum obtained from a spectrophotometer (or a fluorescence spectrophotometer).

[0123] As used here, "first absorption peak wavelength" refers to the wavelength of the first main peak that appears in the lowest energy region of the ultraviolet-visible absorption spectrum.

[0124] Nanostructures can be incorporated into a variety of electronic devices. The electronic and / or optical properties of nanostructures can be controlled, for example, by the elemental composition, size, and / or shape of the nanostructure. In embodiments, luminescent nanostructures can comprise semiconductor nanocrystal particles. Luminescent nanostructures (e.g., quantum dots) can have a relatively large surface area per unit volume, and thus can exhibit a quantum confinement effect that exhibits physical and optical properties different from those of corresponding bulk materials with the same composition. Therefore, luminescent nanostructures (such as quantum dots) can absorb energy (e.g., incident light) supplied from an excitation source to form excited states capable of emitting energies corresponding to their bandgap energies upon relaxation.

[0125] Emitting nanostructures can be fabricated into patterned composites (e.g., patterned polymer composites) for application in color conversion panels (e.g., luminescent color filters) or display panels comprising such composites. In embodiments, unlike liquid crystal display devices with white backlight units, the display panel may include a quantum dot-based color conversion panel or luminescent color filter at a position relative to the front (top) of the display panel. This color conversion panel or filter can transform the emission spectrum of incident light from the luminescent panel into a more desired spectrum (e.g., for red or green light). Furthermore, due to the increased scattering of the converted light in all directions, such a display panel can provide a relatively wide viewing angle, thus addressing the light loss problem caused by absorptive color filters.

[0126] In display devices that include such color conversion panels, the properties (e.g., optical properties or stability) of the light-emitting nanostructures can affect the display quality of the device. For example, since the color conversion panel is positioned at the relatively forward position of the device (e.g., the light extraction surface), not only the luminous efficiency of a given light-emitting material used in the color conversion panel but also the incident light absorption can have a considerable impact on the device, and improvements in these aspects are desirable. When the color conversion panel is used as a patterned film such as a color filter (e.g., in a display), a decrease in the excitation light absorption of the light-emitting material may result in blue light leakage in the display device, which in turn adversely affects color reproducibility (e.g., DCI matching rate). Since the display device can employ an absorptive color filter to prevent blue light leakage, blue light leakage also leads to a decrease in luminous efficiency. Furthermore, the low absorption of the light-emitting nanostructure translates into a reduced brightness level in the device including the light-emitting nanostructure.

[0127] Currently, most quantum dots exhibiting optical properties suitable for electronic devices such as displays are cadmium-based quantum dots, as understood by those skilled in the art. However, cadmium causes serious environmental / health problems and concerns and is one of the restricted elements. Therefore, much research has been conducted on cadmium-free luminescent nanostructures based on group III-V nanocrystals, but cadmium-free luminescent nanostructures based on group III-V (e.g., indium phosphide) tend to exhibit poorer stability (e.g., chemical and thermal stability) than cadmium-based nanocrystals. Furthermore, group III-V nanocrystals exhibit significant degradation, especially after they have undergone the processes required for application in electronic devices. In this regard, attempts have been made to improve luminescent properties or stability by passivating InP-based cores with a relatively increased shell thickness. The shell can include group II-VI compounds such as ZnS, ZnSe, and ZnSeS. However, providing a uniform shell on an InP-based core may present other technical challenges that need to be addressed.

[0128] Without being bound by any theoretical constraints, the III-V compound-based nanostructures used as emission centers may be prone to oxidation, potentially resulting in more defects. One possible solution is to use a thicker shell to achieve fewer oxidation defects, thus obtaining more desirable luminescent properties. Furthermore, such a thick shell can also provide increased thermal stability of the nanostructure to resist the relatively high temperatures that may arise during device operation.

[0129] However, the inventors have discovered that increasing the thickness of the shell has a considerably detrimental effect on optical properties (e.g., the absorption of incident light by the nanostructure). Without being bound by any theory, increasing the shell thickness tends to increase the weight of the nanostructure, which in turn leads to a reduction in the total number of nanostructures for a given weight of nanostructure group (e.g., included in the composite), resulting in a composite that tends to exhibit reduced absorption of incident light.

[0130] Therefore, providing indium phosphide-based luminescent nanostructures with both high absorption and high luminescence efficiency remains a technological challenge and may be difficult to achieve in display technology.

[0131] Furthermore, regarding light absorption, most (or almost all) indium phosphide-based luminescent nanostructures that emit green light with desired luminous efficiency exhibit absorption curves showing a decrease in absorbance with increasing wavelength (specifically, in the blue light region from about 450 nm to about 470 nm). The inventors have found that, for example, when using an OLED emitting light with wavelengths greater than 450 nm as the incident light source, such a UV-Vis absorption curve leads to a relatively sharp decrease in the absorbance of the nanostructure composite. Therefore, it is desirable to develop a luminescent nanostructure that can maintain a relatively high level of incident light absorption when an OLED is used as the incident light source.

[0132] The embodiments provide light-emitting nanostructures (e.g., quantum dots) comprising: a first semiconductor nanocrystal; and a relatively thin second nanocrystal that can effectively passivate the first semiconductor nanocrystal and confine electrons within or relatively confined to the first semiconductor nanocrystal. By means of the features described herein (e.g., composition, structure, or combinations thereof), the light-emitting nanostructures of the embodiments can effectively confine electrons within an emission center (e.g., an indium phosphide-based first semiconductor nanocrystal). Furthermore, such nanostructures can exhibit a relatively increased level of (thermal) stability and can also exhibit improved absorption of incident light. In the embodiments, the second semiconductor nanocrystal included in the light-emitting nanostructure (e.g., as a single shell) can provide a sufficiently high bandgap energy than the first semiconductor nanocrystal, and it can have a reduced level of lattice mismatch. In this way, the designed nanostructure can be advantageous for passivation and provides improved stability even when the device including the light-emitting nanostructure operates at high temperatures.

[0133] In an embodiment, a nanostructure having a “single shell” can be a nanostructure comprising a core (i.e., a first semiconductor nanocrystal) and a shell disposed on a surface throughout the core and having a substantially single composition, such that the single composition comprises, for example, a homogeneous alloy or gradient alloy of at least three elements in the thickness direction (see [link to documentation]). Figure 1B In a single shell, the portion or layer of the shell directly on or in contact with the core may include zinc, selenium, and sulfur. In embodiments, the shell may have a gradient concentration of different elements, provided, for example, by the shell precursors described herein. In embodiments, a single shell may have a certain amount of one element (e.g., sulfur) with concentrations increasing from the core surface to the outermost surface of the luminescent nanostructure. Figure 1B In the shell region, the degree of darkness can represent the concentration of sulfur.

[0134] In an embodiment, the color conversion panel includes a color conversion layer containing color conversion areas (e.g., two or more areas). Figure 1AThis is a schematic diagram of the color conversion panel in an embodiment. (Refer to...) Figure 1A The color conversion panel may also include partition walls (e.g., black matrices, embankments, or combinations thereof, as shown) to define regions of the color conversion layer. The color conversion layer may be a patterned thin film comprising a composite including luminescent nanostructures. The color conversion region may include (e.g., receiving incident light and) a first region configured to emit a first light (e.g., green light). The first region may be arranged to correspond to a green pixel. The first region may include a first (luminescent) composite. In embodiments, the first composite may include a matrix (e.g., a polymer matrix) and a plurality of luminescent nanostructures (hereinafter, sometimes simply referred to as "nanostructures") dispersed within the matrix. The first composite (or the first region) may be configured to emit green light. The luminescent nanostructures included therein may be configured to emit green light upon excitation (or upon illumination with incident light).

[0135] The maximum emission peak wavelength of green light (or luminescent nanostructures) can be greater than or equal to about 500 nm, greater than or equal to about 501 nm, greater than or equal to about 504 nm, or greater than or equal to about 505 nm. The maximum emission peak wavelength of green light (or luminescent nanostructures) can be less than or equal to about 530 nm, less than or equal to about 525 nm, less than or equal to about 520 nm, less than or equal to about 515 nm, or less than or equal to about 510 nm.

[0136] The color conversion region may further include a second region configured to emit light of a different color than green light (e.g., emitting red light). The second region may include a second (luminescent) complex. The luminescent complex disposed in the second region may include a matrix and luminescent nanostructures dispersed in the matrix, and is configured to emit light of a different color than the first complex in the first region (e.g., red light). The second light may be red light having a maximum emission peak wavelength of about 600 nm to about 650 nm (e.g., about 620 nm to about 650 nm).

[0137] The color conversion panel may also include a third region (e.g., including a third complex) capable of emitting or transmitting blue light. The maximum emission peak wavelength of the blue light may be the same as described herein. In embodiments, the maximum emission peak wavelength of the blue light may be greater than or equal to about 380 nm (e.g., greater than or equal to about 440 nm, greater than or equal to about 445 nm, greater than or equal to about 450 nm, greater than or equal to about 455 nm) and less than or equal to about 480 nm, less than or equal to about 475 nm, less than or equal to about 470 nm, less than or equal to about 465 nm, less than or equal to about 460 nm.

[0138] In embodiments, the luminescent nanostructure included in the first composite may include a first semiconductor nanocrystal comprising a group III-V compound and a second semiconductor nanocrystal comprising a zinc chalcogenide. The nanostructure (or each of these) may have a core-shell structure comprising a core and disposed on the core. The core may include the first semiconductor nanocrystal. The shell may include the second semiconductor nanocrystal. The luminescent nanostructure may not include cadmium. The luminescent nanostructure may not include cadmium, lead, mercury, or combinations thereof.

[0139] Group III-V compounds include indium, phosphorus, and optionally zinc. Group III-V compounds may or may not include gallium. Group III-V compounds may include indium phosphide, indium zinc phosphide, or combinations thereof.

[0140] The first semiconductor nanocrystal or core can be the emission center of a light-emitting nanostructure. The size of the first semiconductor nanocrystal or core can be selected considering the desired maximum emission peak wavelength of the light-emitting nanostructure. In embodiments, the first semiconductor nanocrystal or core can have a size (or average size) greater than or equal to about 1 nm, greater than or equal to about 1.5 nm, greater than or equal to about 2 nm, greater than or equal to about 2.5 nm, greater than or equal to about 2.8 nm, greater than or equal to about 3 nm, or greater than or equal to about 3.5 nm. In embodiments, the first semiconductor nanocrystal or core can have a size (or average size) less than or equal to about 5 nm, less than or equal to about 4.5 nm, less than or equal to about 4 nm, less than or equal to about 3.8 nm, or less than or equal to about 3.5 nm.

[0141] In embodiments, the outermost layer or surface of the nanostructure may include zinc, selenium, and sulfur. In embodiments, at least a portion of the surface of the luminescent nanostructure may include a second semiconductor nanocrystal comprising a zinc chalcogenide containing zinc, selenium, and sulfur. First semiconductor nanocrystals comprising group III-V compounds containing indium and phosphorus may exhibit covalent bonding properties and oxidation sensitivity. However, in the luminescent nanostructures of the embodiments, a second semiconductor nanocrystal having a relatively thin thickness (e.g., less than or equal to about 5 monolayers) can provide a first semiconductor nanocrystal with improved passivation (see...). Figure 1B In an embodiment, the second semiconductor nanocrystal may comprise a ZnSeS alloy containing ZnS at a location adjacent to the first semiconductor nanocrystal, and is not bound by theory, but it is believed that its wider band gap can more effectively confine electrons within the first semiconductor nanocrystal while maintaining reduced lattice mismatch. In an embodiment, the amount of sulfur in the second semiconductor nanocrystal increases, for example, toward the surface of the luminescent nanostructure, which can further contribute to additional enhancements in high-temperature stability.

[0142] The inventors have also discovered that as the concentration of sulfur in a ZnSeS shell of relatively thin thickness increases, for example, the superposition between electrons and holes can increase, which can contribute to increased light absorption of the luminescent nanostructure. Furthermore, the inventors have also discovered that as the concentration of sulfur in a ZnSeS shell of relatively thin thickness increases from the core outwards, the probability of electrons residing (or remaining) within the first semiconductor nanocrystal increases, which in turn can technically contribute to surface passivation and / or efficiency (e.g., luminescence efficiency), such as increased surface passivation and / or efficiency. In embodiments, the luminescent nanostructure may include a suitable amount of sulfur not only at its surface but also in adjacent portions of the core and shell, whereby the lattice mismatch or lattice strain between the core and shell can be maintained at a relatively low level, and whereby the wider band gap of the second semiconductor nanocrystal can effectively confine electrons within the first semiconductor nanocrystal (i.e., the core).

[0143] In an embodiment, the light-emitting nanostructure includes a second semiconductor nanocrystal or shell, which can exhibit a reduced level of lattice mismatch and effectively prevent electron leakage to the outside of the emission center. The second semiconductor nanocrystal can have a relatively thin thickness and can include an increased amount of sulfur, thereby providing an enhanced level of stability (thermal stability) for the light-emitting nanostructure. Additionally, the relatively thin thickness of the second semiconductor nanocrystal can provide a relatively increased weight percentage of the first semiconductor nanocrystal within the nanostructure, which can lead to increased light absorption by the light-emitting nanostructure.

[0144] In embodiments, the luminescent nanostructure, including a second semiconductor nanocrystal or shell, can exhibit a reduced level of electron leakage. In embodiments, the luminescent nanostructure can be mixed with a predetermined amount of benzyl viologen, and the relative reduction in photoluminescence efficiency of the luminescent nanostructure can be experimentally determined. In embodiments, the luminescent nanostructure can exhibit a reduction (or loss) in photoluminescence efficiency of less than or equal to about 15%, less than or equal to about 14%, less than or equal to about 13%, less than or equal to about 12%, less than or equal to about 11%, or less than or equal to about 10%. For example, to perform such an experiment, the predetermined amount of benzyl viologen added to the luminescent nanostructure can be less than or equal to about 130 μL or less than or equal to about 100 μL (and / or greater than or equal to about 60 μL, greater than or equal to about 70 μL, greater than or equal to about 80 μL, or greater than or equal to about 90 μL). The mixing can be performed using a dispersion prepared by dispersing 500 μg of the luminescent nanostructure in 3 mL of toluene. The concentration of benzyl viologen can be 0.2 mmol (mM).

[0145] The second semiconductor nanocrystal includes a zinc sulfide, which may include ZnSe, ZnSeS, ZnS, or combinations thereof. The second semiconductor nanocrystal or zinc sulfide may include ZnSeS. The second semiconductor nanocrystal may also include a combination of a first zinc sulfide and a second zinc sulfide, wherein the first zinc sulfide comprises zinc selenide and the second zinc sulfide comprises zinc sulfide.

[0146] The thickness of the second semiconductor nanocrystal or shell (or a single shell) can be less than or equal to about 6 monolayers (ML), less than or equal to about 5.5 ML, less than or equal to about 5 ML, less than or equal to about 4.5 ML, less than or equal to about 4 ML, less than or equal to about 3.5 ML, less than or equal to about 3 ML, or less than or equal to about 2.5 ML. The thickness of the second semiconductor nanocrystal or (single) shell can be greater than or equal to about 2 ML, greater than or equal to about 2.5 ML, greater than or equal to about 3 ML, or greater than or equal to about 3.5 ML. The thickness of the second semiconductor nanocrystal or shell can be less than or equal to about 2.5 nm, less than or equal to about 2.4 nm, less than or equal to about 2.3 nm, less than or equal to about 2.2 nm, less than or equal to about 2.1 nm, less than or equal to about 2 nm, less than or equal to about 1.9 nm, less than or equal to about 1.8 nm, less than or equal to about 1.7 nm, less than or equal to about 1.6 nm, less than or equal to about 1.55 nm, less than or equal to about 1.5 nm, less than or equal to about 1.45 nm, less than or equal to about 1.4 nm, or less than or equal to about 1.35 nm. The thickness of the second semiconductor nanocrystal or (single) shell can be greater than or equal to about 0.6 nm, greater than or equal to about 0.7 nm, greater than or equal to about 0.8 nm, greater than or equal to about 0.9 nm, or greater than or equal to about 1 nm.

[0147] In an embodiment, the shell may be a single shell comprising a second semiconductor nanocrystal. The single shell may have a composition that varies radially. In an embodiment, the concentration of sulfur in the shell (or a single shell) may increase toward the outer surface of the luminescent nanostructure.

[0148] In embodiments, the shell can be a multilayer shell comprising at least two shell layers, wherein adjacent shell layers can have different compositions from each other. The multilayer shell can include: a first shell layer comprising zinc, selenium, and optionally sulfur; and a second shell layer disposed on the first shell layer, the second shell layer comprising zinc, sulfur, and optionally selenium. The amount (e.g., molar amount) in the second shell layer can be greater than the amount (e.g., molar amount) in the first shell layer. The first or second shell layer can include ZnSe, ZnS, ZnSeS, or combinations thereof. The first shell layer can be disposed on a semiconductor nanocrystal core (e.g., directly on a semiconductor nanocrystal core). The second shell layer can be disposed on the first shell layer (e.g., directly on the first shell layer). The second shell layer can be the outermost layer of a light-emitting nanostructure.

[0149] The thickness of the first shell can be less than or equal to about 1 nm, less than or equal to about 0.9 nm, less than or equal to about 0.8 nm, less than or equal to about 0.7 nm, or less than or equal to about 0.6 nm. The thickness of the first shell can be greater than or equal to about 0.3 nm, greater than or equal to about 0.4 nm, or greater than or equal to about 0.5 nm.

[0150] The thickness of the second shell can be less than or equal to about 1 nm, less than or equal to about 0.9 nm, less than or equal to about 0.8 nm, less than or equal to about 0.7 nm, or less than or equal to about 0.6 nm. The thickness of the second shell can be greater than or equal to about 0.3 nm, greater than or equal to about 0.4 nm, or greater than or equal to about 0.5 nm.

[0151] In embodiments, (e.g., as measured by suitable tools such as inductively coupled plasma atomic emission spectrometry or determined by compositional analysis of the structure) the thickness of the zinc selenide layer or the first shell layer in the luminescent nanostructure or within the shell may be less than or equal to about 4 monolayers (ML), less than or equal to about 3.5 ML, less than or equal to about 3 ML, less than or equal to about 2.5 ML, less than or equal to about 2.3 ML, or less than or equal to about 2 ML. The thickness of the zinc selenide layer or the first shell layer may be greater than or equal to about 0.5 ML, greater than or equal to about 1 ML, greater than or equal to about 1.5 ML, greater than or equal to about 2 ML, or greater than or equal to about 2.3 ML. As confirmed by compositional analysis, the thickness of the zinc selenide layer or the first shell layer may be less than or equal to about 1.2 nm, less than or equal to about 1 nm, less than or equal to about 0.9 nm, less than or equal to about 0.8 nm, or less than or equal to about 0.7 nm and / or greater than or equal to about 0.3 nm, greater than or equal to about 0.5 nm, or greater than or equal to about 0.55 nm.

[0152] In embodiments, (e.g., as measured by suitable tools such as inductively coupled plasma atomic emission spectrometry or determined by compositional analysis of the structure) the thickness of the zinc sulfide layer or the second shell layer in the luminescent nanostructure or within the shell may be less than or equal to about 1 nm, less than or equal to about 0.9 nm, less than or equal to about 0.8 nm, less than or equal to about 0.7 nm, or less than or equal to about 0.6 nm. If confirmed by compositional analysis, the thickness of the zinc sulfide layer or the second shell layer may be greater than or equal to about 0.3 nm, greater than or equal to about 0.4 nm, or greater than or equal to about 0.5 nm. In the luminescent nanostructure or within the shell, the thickness of the zinc sulfide layer or the second shell layer may be greater than or equal to about 0.5 mL, greater than or equal to about 1 mL, greater than or equal to about 1.5 mL, greater than or equal to about 2 mL, or greater than or equal to about 2.5 mL and less than or equal to about 5 mL, less than or equal to about 4 mL, less than or equal to about 3 mL, less than or equal to about 2.5 mL, less than or equal to about 2 mL, or less than or equal to about 1.5 mL.

[0153] In the luminescent nanostructures of the embodiments, the molar ratio of sulfur to selenium (S:Se) can be greater than or equal to about 2:1. The molar ratio of sulfur to selenium (S:Se) can be greater than or equal to about 0.5:1, greater than or equal to about 2:1, greater than or equal to about 2.1:1, greater than or equal to about 2.2:1, greater than or equal to about 2.3:1, greater than or equal to about 2.4:1, greater than or equal to about 2.5:1, greater than or equal to about 2.52:1, greater than or equal to about 2.55:1, greater than or equal to about 2.6:1, greater than or equal to about 2.62:1, greater than or equal to about 2.65:1, or greater than or equal to about 2.7:1. In the luminescent nanostructures of the embodiments, the molar ratio of sulfur to selenium (S:Se) can be less than or equal to about 10:1, less than or equal to about 8:1, less than or equal to about 6:1, less than or equal to about 5.5:1, less than or equal to about 5:1, less than or equal to about 4.5:1, less than or equal to about 4:1, less than or equal to about 3.7:1, less than or equal to about 3.5:1, less than or equal to about 3.4:1, less than or equal to about 3.3:1, less than or equal to about 3.2:1, less than or equal to about 3.1:1, less than or equal to about 3:1, less than or equal to about 2.9:1, less than or equal to about 2.8:1, less than or equal to about 2.7:1, less than or equal to about 2.6:1, less than or equal to about 2.5:1, less than or equal to about 2.4:1, less than or equal to about 2.3:1, less than or equal to about 2.2:1, or less than or equal to about 2.1:1.

[0154] In the luminescent nanostructures of the embodiments, the molar ratio of sulfur to indium (S:In) can be greater than or equal to about 3:1, greater than or equal to about 3.5:1, greater than or equal to about 4:1, greater than or equal to about 4.5:1, greater than or equal to about 5:1, greater than or equal to about 5.5:1, greater than or equal to about 6:1, greater than or equal to about 6.5:1, greater than or equal to about 7:1, greater than or equal to about 7.5:1, greater than or equal to about 8:1, greater than or equal to about 8.5:1, greater than or equal to about 9:1, greater than or equal to about 9.5:1, greater than or equal to about 10:1, greater than or equal to about 10.5:1, or greater than or equal to about 11:1. In the luminescent nanostructures of the embodiments, the molar ratio of sulfur to indium can be less than or equal to about 20:1, less than or equal to about 19:1, less than or equal to about 18:1, less than or equal to about 17:1, less than or equal to about 16:1, less than or equal to about 15:1, less than or equal to about 14.5:1, less than or equal to about 14:1, less than or equal to about 13.5:1, less than or equal to about 13:1, less than or equal to about 12.5:1, less than or equal to about 12:1, or less than or equal to about 11.5:1.

[0155] In the luminescent nanostructures of the embodiments, the molar ratio of selenium to indium (Se:In) can be less than or equal to about 10:1, less than or equal to about 9:1, less than or equal to about 8:1, less than or equal to about 7:1, less than or equal to about 6.5:1, less than or equal to about 6:1, less than or equal to about 5.5:1, less than or equal to about 5:1, less than or equal to about 4.8:1, or less than or equal to about 4.5:1. The molar ratio of selenium to indium (Se:In) can be greater than or equal to about 1:1, greater than or equal to about 1.5:1, greater than or equal to about 2:1, greater than or equal to about 2.5:1, greater than or equal to about 3:1, greater than or equal to about 3.5:1, greater than or equal to about 3.8:1, or greater than or equal to about 4:1.

[0156] In the luminescent nanostructures of the embodiments, the molar ratio of zinc to indium (Zn:In) can be less than or equal to about 30:1, less than or equal to about 29:1, less than or equal to about 28:1, less than or equal to about 27:1, less than or equal to about 26:1, less than or equal to about 25:1, less than or equal to about 24:1, less than or equal to about 23:1, less than or equal to about 22:1, less than or equal to about 21:1, less than or equal to about 20:1, less than or equal to about 19:1, less than or equal to about 18:1, less than or equal to about 17:1, less than or equal to about 16:1, less than or equal to about 15:1, or less than or equal to about 14:1. In the luminescent nanostructures of the embodiments, the molar ratio of zinc to indium (Zn:In) can be greater than or equal to about 3:1, greater than or equal to about 4:1, greater than or equal to about 5:1, greater than or equal to about 6:1, greater than or equal to about 7:1, greater than or equal to about 8:1, greater than or equal to about 9:1, greater than or equal to about 10:1, greater than or equal to about 11:1, greater than or equal to about 12:1, greater than or equal to about 13:1, greater than or equal to about 14:1, greater than or equal to about 15:1, greater than or equal to about 16:1, greater than or equal to about 17:1, greater than or equal to about 18:1, greater than or equal to about 19:1, or greater than or equal to about 19.5:1.

[0157] In the luminescent nanostructures of the embodiments, the molar ratio of phosphorus to indium (P:In) can be greater than or equal to about 0.7:1, greater than or equal to about 0.75:1, greater than or equal to about 0.8:1, greater than or equal to about 0.85:1, greater than or equal to about 0.88:1, greater than or equal to about 0.89:1, greater than or equal to about 0.9:1, greater than or equal to about 0.93:1, or greater than or equal to about 0.95:1. The molar ratio of phosphorus to indium (P:In) can be less than or equal to about 1.5:1, less than or equal to about 1.4:1, less than or equal to about 1.3:1, less than or equal to about 1.2:1, less than or equal to about 1.05:1, less than or equal to about 1.03:1, less than or equal to about 1:1, less than or equal to about 0.98:1, less than or equal to about 0.97:1, less than or equal to about 0.96:1, or less than or equal to about 0.95:1.

[0158] In the luminescent nanostructure of the embodiment, the molar ratio of indium to chalcogen elements (e.g., the sum of S and Se) (In:(S+Se)) can be greater than or equal to about 0.05:1, greater than or equal to about 0.06:1, greater than or equal to about 0.062:1, or greater than or equal to about 0.065:1. In the luminescent nanostructures of the embodiments, the molar ratio of indium to chalcogen elements (e.g., the sum of S and Se) (In:(S+Se)) can be less than or equal to about 0.15:1, less than or equal to about 0.14:1, less than or equal to about 0.13:1, less than or equal to about 0.12:1, less than or equal to about 0.11:1, less than or equal to about 0.105:1, less than or equal to about 0.1:1, less than or equal to about 0.095:1, less than or equal to about 0.09:1, less than or equal to about 0.085:1, less than or equal to about 0.08:1, or less than or equal to about 0.075:1.

[0159] In the luminescent nanostructures of the embodiments, the molar ratio of zinc to chalcogen elements (e.g., the sum of S and Se) (Zn:(S+Se)) can be greater than or equal to about 1:1, greater than or equal to about 1.05:1, greater than or equal to about 1.1:1, greater than or equal to about 1.15:1, greater than or equal to about 1.2:1, greater than or equal to about 1.25:1, or greater than or equal to about 1.3:1. In the luminescent nanostructures of the embodiments, the molar ratio of zinc to chalcogen elements (e.g., the sum of S and Se) (Zn:(S+Se)) can be less than or equal to about 2:1, less than or equal to about 1.9:1, less than or equal to about 1.8:1, less than or equal to about 1.7:1, less than or equal to about 1.6:1, less than or equal to about 1.5:1, less than or equal to about 1.45:1, or less than or equal to about 1.4:1.

[0160] At the surface of the luminescent nanostructure, the molar ratio of selenium to the sum of selenium and sulfur can be greater than 0, greater than or equal to about 0.001:1, greater than or equal to about 0.01:1 and less than or equal to about 0.3:1, or less than or equal to about 0.2:1.

[0161] The amount of components included in quantum dots as described herein can be determined, for example, using appropriate analytical tools such as inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray photoelectron spectroscopy (XPS), ion chromatography, Rutherford backscattering spectroscopy (RBS), time-of-flight secondary ion mass spectrometry (TOF-SIMS), transmission electron microscopy energy-dispersive X-ray spectroscopy (TEM-EDS), etc.

[0162] The method for fabricating the aforementioned luminescent nanostructures according to the embodiments includes: preparing a semiconductor nanocrystal (or a core particle including thereof) comprising indium (In) and phosphorus (P) and optionally zinc; and reacting a zinc precursor with at least one of a selenium precursor and a sulfur precursor in the presence of the first semiconductor nanocrystal and a first organic ligand (e.g., in an organic solvent) to form a second semiconductor nanocrystal (or a shell including thereof). The shell precursors may be added simultaneously or sequentially.

[0163] In this method, during the formation of the second semiconductor nanocrystal, a selenium precursor and a sulfur precursor may be added, such that at least a portion of the surface of the nanostructure or the outermost layer of the nanostructure includes zinc, sulfur, and selenium.

[0164] In an embodiment, during the formation of the second semiconductor nanocrystal, a selenium precursor and a sulfur precursor may be added such that the portion adjacent to the core (or the innermost layer of the second semiconductor nanocrystal) comprises zinc, sulfur, and selenium.

[0165] In an embodiment, during the formation of the second semiconductor nanocrystal, a selenium precursor and a sulfur precursor may be added such that the thickness of the second semiconductor nanocrystal in the prepared nanostructure is less than or equal to about 5 monolayers (or less than or equal to about 2 nm or less than or equal to about 1.5 nm).

[0166] In an embodiment, during the formation of the second semiconductor nanocrystal, a selenium precursor and a sulfur precursor may be added such that the molar ratio of sulfur to selenium in the prepared nanostructure is greater than or equal to about 2:1.

[0167] The preparation of semiconductor nanocrystal cores may include: heating an indium compound in the presence of a second organic ligand and an organic solvent to prepare an indium precursor solution; and injecting a phosphorus precursor into the indium precursor solution and heating the resulting mixture. The method may also include obtaining a zinc precursor prior to the preparation of the indium precursor solution and preparing the indium precursor solution in the presence of the zinc precursor. Depending on the type, the zinc precursor may be obtained by heating the zinc compound and the organic ligand in an organic solvent at a high temperature (e.g., greater than or equal to about 100°C and less than or equal to about 200°C). During nucleosynthesis, the molar ratio of zinc to indium (Zn:In) (e.g., in the precursor used) may be greater than or equal to about 1:1, greater than or equal to about 1.1:1, greater than or equal to about 1.2:1 and less than or equal to about 3:1, less than or equal to about 2.5:1, or less than or equal to about 2:1.

[0168] In embodiments, the zinc precursor and indium precursor may include a carboxylate (e.g., C1 to C24 carboxylate) portion. The number of moles of carboxylate-containing organic ligands per mole of metal in the zinc precursor (or indium precursor) may be greater than or equal to about 1 mole, greater than or equal to about 1.5 moles, greater than or equal to about 2 moles and less than or equal to about 5 moles, less than or equal to about 4 moles, or less than or equal to about 3 moles.

[0169] In embodiments, the reaction medium used to form the second semiconductor nanocrystal may include a sulfur precursor and a selenium precursor. In the formation of the second semiconductor nanocrystal, a zinc precursor, a first organic ligand, and an organic solvent are mixed and heated at a predetermined temperature (e.g., greater than or equal to about 100°C, greater than or equal to about 120°C, greater than or equal to about 130°C, greater than or equal to about 140°C, greater than or equal to about 150°C, or greater than or equal to about 200°C and less than or equal to about 300°C, less than or equal to about 280°C, less than or equal to about 250°C, less than or equal to about 230°C, or combinations thereof). The first semiconductor nanocrystal, the selenium precursor, and the sulfur precursor (e.g., a reaction product of a thiol compound, an alkylphosphine compound, and sulfur, or combinations thereof) may be added to the heated mixture. The selenium precursor and the sulfur precursor may be added to form a second semiconductor nanocrystal of the desired composition (e.g., added independently or uniformly at least once or at least twice). There are no particular limitations on the manner of addition; they may be added simultaneously or sequentially.

[0170] The formation of the shell can include forming a first semiconductor nanocrystal shell comprising zinc, sulfur, and selenium on a semiconductor nanocrystal core (hereinafter, the first shell formation process) and forming a second semiconductor nanocrystal shell comprising zinc and sulfur, and selenium as needed, on the first semiconductor nanocrystal shell (hereinafter, the second shell formation process). During shell formation, the amount of each of the precursors (e.g., zinc precursor, selenium precursor, and / or sulfur precursor) can be controlled by considering the structure and composition of the final core-shell quantum dot.

[0171] There are no particular limitations on the zinc precursor, and it can be appropriately selected. For example, the zinc precursor can be Zn metal powder, alkylated Zn compounds, Zn alkoxides, Zn carboxylates, Zn nitrates, Zn perchlorates, Zn sulfates, Zn acetylacetonates, Zn halides, Zn cyanides, Zn hydroxides, Zn oxides, Zn peroxides, or combinations thereof. The zinc precursor can be dimethyl zinc, diethyl zinc, zinc acetate, zinc acetylacetonate, zinc iodide, zinc bromide, zinc chloride, zinc fluoride, zinc carbonate, zinc cyanide, zinc nitrate, zinc oxide, zinc peroxide, zinc perchlorate, zinc sulfate, etc. The zinc precursor can be used alone or in combination of two or more. In the examples, zinc chloride may or may not be used to form semiconductor nanocrystals.

[0172] (First and / or second) Organic ligands may include RCOOH, RNH2, R2NH, R3N, RSH, RH2PO, R2HPO, R3PO, RH2P, R2HP, R3P, ROH, RCOOR', RPO(OH)2, RHPOOH, R2POOH (wherein R and R' are independently C1 to C40 (or C3 to C24) aliphatic hydrocarbon groups (e.g., alkyl, alkenyl, alkynyl) or C6 to C40 (or C6 to C24) aromatic hydrocarbon groups (e.g., C6 to C20 aryl)) or combinations thereof. The organic ligands can coordinate to the surface of the obtained nanocrystals and can improve the dispersion of the nanocrystals in solution and / or achieve the luminescent and electrical properties of the luminescent nanocrystals. Examples of organic ligands may include thiols, such as methanethiol, ethanethiol, propanethiol, butanethiol, pentylenetetrazol, hexanethiol, octanethiol, dodecanethiol, hexadecanethiol, octadecanethiol, and benzylthiol; amines, such as methylamine, ethylamine, propylamine, butylamine, pentylemine, hexylamine, octylamine, dodecaneamine, hexadecaneamine, octadecaneamine, dimethylamine, diethylamine, or dipropylamine; carboxylic acids, such as formic acid (or formic acid), acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, dodecanoic acid, hexadecanoic acid, octadecanoic acid, oleic acid, and benzoic acid; and phosphines, such as substituted or unsubstituted methylphosphine (e.g., trimethylphosphine, methyldiphenylphosphine, etc.), substituted or unsubstituted ethylphosphine (e.g., triethylphosphine, ethyldiphenylphosphine, etc.), substituted or unsubstituted propylphosphine, substituted or unsubstituted butylphosphine, substituted or unsubstituted pentylphosphine, and substituted or unsubstituted phosphine. Octylphosphine (e.g., trioctylphosphine (TOP)); phosphine oxides, such as substituted or unsubstituted methylphosphine oxides (e.g., trimethylphosphine oxide, methyldiphenylphosphine oxide, etc.), substituted or unsubstituted ethylphosphine oxides (e.g., triethylphosphine oxide, ethyldiphenylphosphine oxide, etc.), substituted or unsubstituted propylphosphine oxides, substituted or unsubstituted butylphosphine oxides, substituted or unsubstituted octylphosphine oxides (e.g., trioctylphosphine oxide (TOPO), etc.); diphenylphosphine, triphenylphosphine compounds, or their oxides; phosphonic acids, C5 to C20 alkylphosphonic acids (such as hexylphosphonic acid, octylphosphonic acid, dodecylphosphonic acid, tetradecylphosphonic acid, hexadecylphosphonic acid, or octadecylphosphonic acid), or C5 to C20 alkylphosphonic acids, but not limited thereto. Organic ligands may be used alone or as a mixture of two or more.

[0173] Organic solvents may be selected from: C6 to C22 primary amines, such as hexadecylamine; C6 to C22 secondary amines, such as dioctylamine; C6 to C40 tertiary amines, such as trioctylamine; nitrogen-containing heterocyclic compounds, such as pyridine; C6 to C40 aliphatic hydrocarbons (e.g., alkanes, alkenes, alkynes, etc.), such as hexadecane, octadecane, octadecene, or squalane; C6 to C30 aromatic hydrocarbons, such as phenyldodecane, phenyltetradecane, or phenylhexadecane; phosphine substituted with C6 to C22 alkyl groups, such as trioctylphosphine; phosphine oxide substituted with C6 to C22 alkyl groups, such as trioctylphosphine oxide; C12 to C22 aromatic ethers, such as phenyl ethers or benzyl ethers, and combinations thereof. The type and amount of solvent may be appropriately selected based on the precursor and organic ligand.

[0174] There are no particular limitations on the types of indium compounds, and they can be suitably selected. Indium precursors may include indium powder, alkylated (e.g., C1-C18 alkylated) indium compounds, indium alkoxides (e.g., C1-C18 alkoxides), indium carboxylic acids (e.g., C1-C18 carboxylates), indium nitrate, indium perchlorate, indium sulfate, indium acetylacetonate, indium halide, indium cyanide, indium hydroxide, indium oxide, indium peroxide, indium carbonate, or combinations thereof. Indium precursors may include indium carboxylate, such as indium oleate, indium myristate, indium acetate, indium hydroxide, indium chloride, indium bromide, or indium iodide, or combinations thereof. The formation of indium precursors can be carried out under vacuum at a temperature greater than or equal to about 100°C, greater than or equal to about 120°C, and less than or equal to about 200°C.

[0175] There are no particular restrictions on the type of phosphorus precursor, and it can be selected appropriately. Phosphorus precursors may include tris(trimethylsilyl)phosphine, tris(dimethylamino)phosphine, triethylphosphine, tributylphosphine, trioctylphosphine, triphenylphosphine, tricyclohexylphosphine, dimethylaminophosphine, diethylaminophosphine, or combinations thereof.

[0176] The mixture obtained during the nucleation process by injecting a phosphorus precursor can be heated to a temperature greater than or equal to about 150°C, greater than or equal to about 200°C, greater than or equal to about 250°C, or greater than or equal to about 270°C and less than or equal to about 300°C, less than or equal to about 290°C, less than or equal to about 280°C, less than or equal to about 270°C, or less than or equal to about 260°C. In embodiments, one or more precursors (e.g., indium precursor, phosphorus precursor, and / or zinc precursor) may be additionally injected once or more during the nucleation process.

[0177] There are no particular restrictions on the nucleation reaction time, and the reactivity between precursors and the nucleation temperature can be appropriately selected.

[0178] In the method of the embodiments, a sulfur precursor (hereinafter, the first sulfur precursor) may be added at a relatively initial stage of the formation of the second semiconductor nanocrystal (e.g., or the first shell). An additional sulfur precursor (hereinafter, the second sulfur precursor, which may be the same or different) may be added again at a later stage of the formation of the second semiconductor nanocrystal (or during the formation of the second shell). The first sulfur precursor may comprise a thiol compound. The second sulfur precursor may comprise sulfur dispersed in an alkylphosphine compound (e.g., a reaction product of sulfur and an alkylphosphine compound). The thiol compound may comprise a thiol compound having a C4-20 aliphatic hydrocarbon group (e.g., an alkane thiol compound, such as dodecanethiol). The second sulfur precursor may comprise an organic solvent dispersion of sulfur powder (e.g., thio-octadecene (S-ODE), thio-trioctylphosphine (S-TOP), thio-tributylphosphine (S-TBP), thio-triphenylphosphine (S-TPP), thio-trioctylamine (S-TOA), or trimethylsilyl sulfide), mercaptopropylsilane, trimethylsilyl sulfide, ammonium sulfide, sodium sulfide, or combinations thereof. The molar ratio (e.g., molar ratio) between the first and second sulfur precursors may be suitably selected. The molar ratio (e.g., molar ratio) of the first to second sulfur precursors may be from about 1:0.1 to about 1:10, from about 1:0.2 to about 1:5, from about 1:0.3 to about 1:3, from about 1:0.4 to about 1:2.5, from about 1:0.5 to about 1:2, or any range derived from such ratios.

[0179] There are no particular restrictions on the type of selenium precursor, and it can be selected appropriately. For example, the selenium precursor can be selenium-trioctylphosphine (Se-TOP), selenium-tributylphosphine (Se-TBP), selenium-triphenylphosphine (Se-TPP), selenium-diphenylphosphine (Se-DPP), or a combination thereof. The selenium precursor can be injected once or more (e.g., twice or more).

[0180] The formation temperature of the second semiconductor nanocrystal (or shell) can be appropriately selected. In embodiments, the formation temperature of the second semiconductor nanocrystal (or shell) can be greater than or equal to about 270°C, greater than or equal to about 280°C, greater than or equal to about 290°C, greater than or equal to about 300°C, greater than or equal to about 310°C, or greater than or equal to about 315°C. In embodiments, the formation temperature of the second semiconductor nanocrystal (or shell) can be less than or equal to about 350°C, less than or equal to about 340°C, less than or equal to about 330°C, or less than or equal to about 325°C.

[0181] In embodiments, the formation temperature of the second semiconductor nanocrystal (or shell) can vary during the formation of a single shell structure or a multilayer shell structure having a first shell layer and a second shell layer. In embodiments, the temperature for the first shell layer or in the initial stage of a single shell (hereinafter, the initial shell formation temperature) can be lower than the temperature for the second shell layer or in the later stage of a single shell (hereinafter, the later shell formation temperature). The difference between the initial shell formation temperature and the later shell formation temperature can be greater than or equal to about 10°C, greater than or equal to about 20°C, greater than or equal to about 30°C, greater than or equal to about 40°C, greater than or equal to about 50°C, or greater than or equal to about 60°C.

[0182] There is no particular limitation on the formation time of the second semiconductor nanocrystal or shell, and it can be appropriately selected. For example, the formation reaction of the second semiconductor nanocrystal or shell can be performed for, for example, more than or equal to about 20 minutes, more than or equal to about 25 minutes, more than or equal to about 30 minutes, more than or equal to about 35 minutes, more than or equal to about 40 minutes, more than or equal to about 45 minutes, more than or equal to about 50 minutes, more than or equal to about 55 minutes, or more than or equal to about 1 hour, but is not limited thereto. The formation reaction time of the second semiconductor nanocrystal or shell can be less than or equal to about 3 hours.

[0183] During the formation of the second semiconductor nanocrystal or shell, precursors / compounds, either individually or as a mixture of two or more, can be added in a single step or in two or more steps. When adding precursors, etc., stepwise, a reaction of a predetermined time (e.g., greater than or equal to about 5 minutes, greater than or equal to about 10 minutes, or greater than or equal to about 15 minutes) can be performed in each step. The reaction can be performed under an inert gas atmosphere, air, or vacuum, but is not limited thereto.

[0184] During the formation of the second semiconductor nanocrystal (e.g., during the formation of the first or second shell), the selenium precursor may be added once or more (e.g., twice or more, or three or more times, etc.). The selenium precursor may be present in the reaction medium during the formation of the second shell or in the later stages of the formation of the second semiconductor nanocrystal.

[0185] In an embodiment, shell formation may include forming a first shell layer and a second shell layer, with each reaction time appropriately selected based on the desired shell composition, the type of precursor, and the reaction temperature.

[0186] The formation of a second semiconductor nanocrystal or shell (e.g., a single shell or a multilayer shell having a first shell layer and a second shell layer) can be performed (e.g., independently) for more than or equal to about 40 minutes, more than or equal to about 50 minutes, more than or equal to about 60 minutes, more than or equal to about 70 minutes, more than or equal to about 80 minutes, or more than or equal to about 90 minutes. The reaction time for the formation of the second semiconductor nanocrystal or shell can be (e.g., independently) less than or equal to about 4 hours, less than or equal to about 3 hours, less than or equal to about 2 hours, less than or equal to about 1 hour, or less than or equal to about 30 minutes.

[0187] In an embodiment, the amount of selenium in each mole of indium in the reaction medium used for the formation of the second semiconductor nanocrystal or shell may be greater than or equal to about 2 moles and less than or equal to about 5 moles (per mole of indium).

[0188] In the reaction medium used for the formation of the second semiconductor nanocrystal or shell, the amount of sulfur in each mole of indium can be greater than or equal to about 6 moles, greater than or equal to about 7 moles, greater than or equal to about 8 moles, greater than or equal to about 9 moles, or greater than or equal to about 10 moles and less than or equal to about 14 moles, less than or equal to about 13 moles, less than or equal to about 12 moles, less than or equal to about 11 moles, less than or equal to about 10 moles, or less than or equal to about 9.5 moles.

[0189] In an embodiment, in the reaction medium used for the formation of the second semiconductor nanocrystal or shell, the amount of the first sulfur precursor (e.g., a thiol compound) per mole of indium can be greater than or equal to about 4 moles, greater than or equal to about 5 moles, greater than or equal to about 6 moles, greater than or equal to about 7 moles, greater than or equal to about 8 moles, greater than or equal to about 9 moles, or greater than or equal to about 10 moles and less than or equal to about 14 moles, less than or equal to about 13 moles, less than or equal to about 12 moles, less than or equal to about 11 moles, less than or equal to about 10 moles, or less than or equal to about 9.5 moles. In the embodiments, in the reaction medium used for the formation of the second semiconductor nanocrystal or shell, the amount of the second sulfur precursor per mole of indium can be greater than or equal to 0 moles, greater than or equal to about 1 mole, greater than or equal to about 3 moles, greater than or equal to about 5 moles, greater than or equal to about 7 moles, greater than or equal to about 9 moles and less than or equal to about 10 moles, less than or equal to about 9 moles, less than or equal to about 8 moles, less than or equal to about 7 moles, less than or equal to about 6 moles, less than or equal to about 5 moles, less than or equal to about 4 moles, less than or equal to about 3 moles, or less than or equal to about 2 moles.

[0190] A non-solvent can be added to the resulting final reaction solution to precipitate the quantum dots, and then the nanocrystals coordinated with the organic ligands can be separated (e.g., by filtration or centrifugation). The non-solvent can be a polar solvent miscible with the solvent used in the reaction, in which the nanocrystals can precipitate (e.g., become non-dispersible). The non-solvent can be selected based on the solvent used in the reaction and can be, for example, acetone, ethanol, butanol, isopropanol, ethylene glycol, water, tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), diethyl ether, formaldehyde, acetaldehyde, solvents having solubility parameters similar to those of the aforementioned solvents, or combinations thereof. Separation can be performed by centrifugation, precipitation, chromatography, or distillation. If desired, the separated nanocrystals can be added to a washing solvent and washed. The washing solvent is not particularly limited and can have a solubility parameter similar to that of the organic ligands, and can include, for example, hexane, heptane, octane, chloroform, toluene, benzene, etc.

[0191] The luminescent nanostructures can be dispersed in a dispersion solvent. The luminescent nanostructures can form an organic solvent dispersion. The organic solvent dispersion may not include water and / or an organic solvent miscible with water. The dispersion solvent can be suitably selected. The dispersion solvent may include the aforementioned organic solvents. The dispersion solvent may include substituted or unsubstituted C1 to C40 aliphatic hydrocarbons, substituted or unsubstituted C6 to C40 aromatic hydrocarbons, or combinations thereof.

[0192] In embodiments, the luminescent nanostructures may have a quantum efficiency (e.g., absolute quantum yield) greater than or equal to about 80%, greater than or equal to about 81%, greater than or equal to about 82%, greater than or equal to about 83%, greater than or equal to about 84%, greater than or equal to about 85%, or greater than or equal to about 90%. In embodiments, the luminescent nanostructures may have a full width at half maximum (FWHM) of less than or equal to about 55 nm, less than or equal to about 50 nm, less than or equal to about 45 nm, less than or equal to about 44 nm, less than or equal to about 43 nm, less than or equal to about 42 nm, less than or equal to about 41 nm, or less than or equal to about 40 nm. In embodiments, when dispersed in an organic solvent, the luminescent nanostructures may exhibit a FWHM greater than or equal to about 40 nm. In embodiments, when dispersed in an organic solvent, the luminescent nanostructures may exhibit a FWHM less than or equal to about 50 nm.

[0193] The size (or average size) of the luminescent nanostructure can be greater than or equal to about 1 nm, greater than or equal to about 2 nm, greater than or equal to about 3 nm, greater than or equal to about 4 nm, or greater than or equal to about 5 nm. Luminescent nanostructures configured to emit green light can have reduced sizes. (e.g., average) sizes can be less than or equal to about 10 nm, less than or equal to about 9 nm, less than or equal to about 8 nm, less than or equal to about 7 nm, less than or equal to about 6.5 nm, less than or equal to about 6 nm, less than or equal to about 5.5 nm, less than or equal to about 5 nm, or less than or equal to about 4.95 nm. Size can be diameter. The size of a luminescent nanostructure (if not spherical) can have an equivalent diameter calculated by converting a two-dimensional region identified by transmission electron microscopy into a circle. As used herein, size (such as dimension) (e.g., quantum dot-related size) can refer to its average (mean or median average) value (e.g., average size).

[0194] There are no particular restrictions on the shape of the luminescent nanostructures, and they can be, for example, spherical, polyhedral, pyramidal, pedigree, cubic, nanotube, nanowire, nanofiber, nanosheet or a combination thereof, but are not limited thereto.

[0195] The luminescent nanostructure may include organic ligands and / or organic solvents on its surface. The organic ligands and / or organic solvents may be incorporated into (e.g., coordinated or bonded to) the surface of the luminescent nanostructure.

[0196] In the embodiments, in the UV-Vis absorption spectrum of the luminescent nanostructure, the ratio of absorbance at the first absorption peak wavelength to absorbance at a wavelength of about 350 nm (i.e., the absorbance ratio) can be greater than or equal to about 0.2:1, greater than or equal to about 0.21:1, greater than or equal to about 0.22:1, greater than or equal to about 0.23:1, greater than or equal to about 0.24:1, greater than or equal to about 0.25:1, or greater than or equal to about 0.26:1 (see...). Figure 1C In the UV-Vis absorption spectrum of the luminescent nanostructure, the ratio of absorbance at the first absorption peak wavelength to absorbance at a wavelength of about 350 nm can be less than or equal to about 0.4:1, less than or equal to about 0.3:1, less than or equal to about 0.29:1, less than or equal to about 0.28:1, less than or equal to about 0.27:1, less than or equal to about 0.26:1, or less than or equal to about 0.255:1. The luminescent nanostructures of the embodiments (as defined in part by their respective UV-Vis absorption spectra) can have absorbance ratios that can be defined by a range derived from any of the maximum and minimum ratios described above.

[0197] The UV-Vis absorption spectrum of the luminescent nanostructure has a positive differential coefficient (i.e., tangential slope) at 450 nm. In the UV-Vis absorption spectrum, the differential coefficient value at 450 nm can be greater than 0, for example, greater than or equal to about 0.001, greater than or equal to about 0.002, greater than or equal to about 0.003, greater than or equal to about 0.004, greater than or equal to about 0.005, or greater than or equal to about 0.006. The differential coefficient value can be less than or equal to about 0.03, less than or equal to about 0.025, less than or equal to about 0.02, less than or equal to about 0.015, less than or equal to about 0.01, less than or equal to about 0.0095, less than or equal to about 0.009, or less than or equal to about 0.0085. The luminescent nanostructure of the embodiment can exhibit improved efficiency and increased absorbance for excitation light greater than or equal to about 450 nm and less than or equal to about 470 nm. The differential coefficient value of UV-Vis absorption at 450 nm (i.e., the derivative of df(x) / dx, the slope of the tangent) can be easily measured by simple analysis of the curve.

[0198] In the UV-Vis absorption spectrum of luminescent nanostructures, the first absorption peak wavelength can exist at a wavelength greater than about 450 nm and less than the photoluminescence emission peak wavelength. The first absorption peak wavelength can exist, for example, in the wavelength range greater than or equal to about 455 nm, greater than or equal to about 460 nm, greater than or equal to about 465 nm, greater than or equal to about 470 nm, greater than or equal to about 475 nm, or greater than or equal to about 480 nm. The first absorption peak wavelength can also exist in the wavelength range less than or equal to about 505 nm, less than or equal to about 500 nm, less than or equal to about 495 nm, or less than or equal to about 490 nm.

[0199] In the UV-Vis absorption spectrum of core-shell quantum dots, the valley depth (VD) defined by the following equations is greater than or equal to about 0.2, greater than or equal to about 0.25, greater than or equal to about 0.3, greater than or equal to about 0.35, and greater than or equal to about 0.4:

[0200] 1-(Abs 谷 / Abs 第一 ) = VD

[0201] Among them, Abs 第一 Corresponding to the absorption rate at the first absorption peak, and Abs 谷 This corresponds to the absorption rate at the lowest point of the valley adjacent to the first absorption peak.

[0202] Core-shell quantum dots can have valley depths greater than or equal to about 0.45 or greater than or equal to about 0.5.

[0203] In the UV-Vis absorption spectrum of luminescent nanostructures, the lowest point of the valley can exist in the range of less than or equal to about 450 nm and greater than or equal to about 400 nm or greater than or equal to about 420 nm.

[0204] The luminescent nanostructures of the embodiments and composites comprising them can emit green light with increased blue light absorption (or improved incident light absorption) and enhanced luminescence efficiency. For example, in the form of composites, the luminescent nanostructures can also exhibit improved thermal stability, for instance, if the device is operated at high temperatures for a period of time. The luminescent nanostructures of the embodiments can also exhibit a high level of chemical stability, and therefore, in processes involving contacting the luminescent nanostructures with a variety of chemical substances (such as organic polymers, organic solvents, monomers, various additives) to prepare compositions (e.g., photoresist compositions or photosensitive compositions) or in processes using compositions to prepare composites or patterned composites, the resulting products (such as compositions or composites (or patterns) of luminescent nanostructures) can also retain their improved luminescent properties.

[0205] In the color conversion panel of the embodiment, a first composite comprising a luminescent nanostructure composite can be prepared, for example, by a process including heat treatment at a high temperature of about 180°C for a period of time greater than or equal to about 30 minutes or less than or equal to about 1 hour in the form of a film (e.g., a patterned film). In the embodiment, the film of the luminescent nanostructure composite may have a thickness greater than or equal to about 6 micrometers (μm) (e.g., greater than or equal to about 7 μm, greater than or equal to about 8 μm, greater than or equal to about 9 μm, greater than or equal to about 10 μm) and less than or equal to about 40 micrometers (μm), less than or equal to about 35 micrometers (μm), less than or equal to about 30 micrometers (μm), less than or equal to about 25 μm, less than or equal to about 20 μm, less than or equal to about 15 μm, less than or equal to about 10 μm, less than or equal to about 8 μm, or less than or equal to about 7 μm.

[0206] In the composite, based on the total weight of the composite, the amount of luminescent nanostructures can be greater than or equal to about 10 wt%, greater than or equal to about 15 wt%, greater than or equal to about 20 wt%, greater than or equal to about 25 wt%, or greater than or equal to about 30 wt% and less than or equal to about 50 wt%, less than or equal to about 45 wt%, or less than or equal to about 40 wt%.

[0207] In a color conversion panel, for incident light having wavelengths of, for example, greater than or equal to about 450 nm, greater than or equal to about 455 nm, greater than or equal to about 457 nm and less than or equal to about 470 nm, less than or equal to about 465 nm, or less than or equal to about 460 nm, the first composite material can exhibit improved and high absorption. The composite material or color filter (e.g., a color conversion panel including it) can be used in a display device and exhibit improved color reproducibility, for example, with or without a blue cutoff filter.

[0208] In embodiments, such as in a color conversion panel, the first composite may exhibit an incident light absorptivity greater than or equal to about 84%, greater than or equal to about 86%, greater than or equal to about 87%, or greater than or equal to about 88%, wherein the incident light absorptivity is defined as follows:

[0209] (B-B') / B×100=Incident light absorptivity (%)

[0210] B: Light dose of incident light

[0211] B': The light dose of the first complex has been obtained.

[0212] In embodiments, such as in a color conversion panel, the first composite material may exhibit a light conversion efficiency greater than or equal to about 33%, greater than or equal to about 34%, greater than or equal to about 35%, greater than or equal to about 36%, greater than or equal to about 37%, greater than or equal to about 38%, greater than or equal to about 39%, greater than or equal to about 40%, greater than or equal to about 41%, or greater than or equal to about 42%, wherein the light conversion efficiency is defined as follows:

[0213] (A / B) × 100 = Light conversion efficiency (%)

[0214] A: Light dose of green light emitted from the first complex

[0215] B: Light dose of incident light.

[0216] The first composite or a film comprising the first composite may exhibit, under irradiation with incident light at wavelengths from about 450 nm to about 460 nm, a loss percentage (hereinafter, QY loss) between its luminous efficiency (QY) at room temperature (e.g., 20 °C to 30 °C) and its luminous efficiency (QY) at about 80 °C, which is less than or equal to about 15%, less than or equal to about 14%, less than or equal to about 13%, less than or equal to about 12.5%, less than or equal to about 12%, less than or equal to about 11%, less than or equal to about 10%, less than or equal to about 9.5%, less than or equal to about 9%, less than or equal to about 8.6%, less than or equal to about 8%, less than or equal to about 7.5%, or less than or equal to about 7.1%, and the loss percentage is defined as follows:

[0217] QY loss (%) = [1 - (QY at 80℃ / QY at room temperature)] × 100.

[0218] When the first complex is irradiated with incident light (e.g., blue light having a wavelength of about 450 nm to about 470 nm or about 458 nm to about 460 nm), the tail percentage, as defined by the following formula, may be less than or equal to about 15%, less than or equal to about 14%, less than or equal to about 13%, less than or equal to about 12%, less than or equal to about 11.5%, or less than or equal to about 11%:

[0219] Trailing percentage (%) = [S2 / S1] × 100

[0220] S1: Total area of ​​the maximum photoluminescence peak of the first complex (or green light)

[0221] S2: The area of ​​the maximum photoluminescence peak of the first complex (or green light) in the wavelength region greater than or equal to about 580 nm.

[0222] The first composite material can exhibit a reduced full width at half maximum (FWHM) level. In the color conversion panel of the embodiment, the first composite material can emit green light with a desired wavelength having an FWHM of less than or equal to about 50 nm, less than or equal to about 45 nm, less than or equal to about 43 nm, less than or equal to about 42 nm, less than or equal to about 40 nm, less than or equal to about 39.5 nm, or less than or equal to about 39 nm, less than or equal to about 38 nm, or less than or equal to about 35 nm. The green light emitted from the first composite material can have a maximum emission peak wavelength greater than or equal to about 500 nm or greater than or equal to about 505 nm. The maximum emission peak wavelength of the green light can be less than or equal to about 530 nm, less than or equal to about 525 nm, less than or equal to about 520 nm, less than or equal to about 515 nm, or less than or equal to about 510 nm.

[0223] In an embodiment, the color conversion panel may include a plurality of first regions, and the color conversion layer may be patterned such that each first region may include a first composite. The composite or a patterned film including the composite may be prepared by photolithography or inkjet printing using an ink composition. Therefore, the embodiment provides a composition comprising a liquid carrier and the aforementioned (e.g., a plurality of) luminescent nanostructures (or groups thereof). The luminescent nanostructures (or groups thereof) may be dispersed in the liquid carrier.

[0224] The liquid carrier may include liquid monomers, organic solvents, or combinations thereof. The ink composition may also include metal oxide fine particles. The ink composition may also include a dispersant in the liquid monomers and / or organic solvents (for dispersing the luminescent nanostructures and / or metal oxide fine particles). The dispersant may include an organic compound (e.g., a monomer or polymer) containing a carboxylic acid (e.g., a C1 to C24 carboxylic acid) group.

[0225] The liquid monomer may include a (photo)polymerizable monomer having, for example, at least one carbon-carbon double bond. The composition may also include a (photo or thermal) initiator. In the composition, polymerization can be initiated by light or heat.

[0226] Details of the luminescent nanostructures in the composition (or composite) are described herein. The amount of luminescent nanostructures in the composition (or composite) can be appropriately controlled, taking into account the desired end use (e.g., a color conversion layer in a photoluminescent color filter or color conversion panel) and the composition (or composite). In embodiments, the amount of luminescent nanostructures may be greater than or equal to about 1 wt%, for example, greater than or equal to about 2 wt%, greater than or equal to about 3 wt%, greater than or equal to about 4 wt%, greater than or equal to about 5 wt%, greater than or equal to about 6 wt%, greater than or equal to about 7 wt%, greater than or equal to about 8 wt%, greater than or equal to about 9 wt%, greater than or equal to about 10 wt%, greater than or equal to about 15 wt%, greater than or equal to about 20 wt%, greater than or equal to about 25 wt%, greater than or equal to about 30 wt%, greater than or equal to about 35 wt%, or greater than or equal to about 40 wt%, based on the total weight or total solids content of the composition. Based on the total weight or total solids content of the composition, the amount of luminescent nanostructures may be less than or equal to about 70 wt%, for example, less than or equal to about 65 wt%, less than or equal to about 60 wt%, less than or equal to about 55 wt%, or less than or equal to about 50 wt%.

[0227] The weight percentage of a component relative to the total solids content in the composition can represent the content of the component in the complex described herein.

[0228] In embodiments, the ink composition may be a photoresist composition comprising a light-emitting nanostructure applicable to photolithography. In embodiments, the ink composition may be an inkjet composition patternable by printing (e.g., droplet ejection methods, such as inkjet printing). The ink composition according to embodiments may not include conjugated (or conductive) polymers (except for the cardo adhesive described later). In embodiments, the composition according to embodiments may include conjugated or conductive polymers. In embodiments, a conjugated polymer refers to a polymer having conjugated double bonds in its main chain (e.g., polyphenylenevinylene, etc.). In embodiments, the composition may not include organic solvents (i.e., it may be a solvent-free system). In embodiments, the amount of a given component in the composition may correspond to the amount of a given component in the first composite.

[0229] In the compositions of the embodiments, the addition of a dispersant can help ensure the dispersibility of the luminescent nanostructures or metal oxide particles described herein. In the embodiments, the dispersant may include a binder (or binder polymer). The dispersant or binder may be an insulating polymer. The binder may include an organic compound (e.g., a monomer or polymer) that optionally includes a carboxylic acid group (e.g., in repeating units). The binder or dispersant may be a carboxylic acid-containing compound.

[0230] The carboxylic acid-containing compound may include a copolymer of a monomer mixture comprising a first monomer containing a carboxylic acid group and a carbon-carbon double bond, a second monomer containing a carbon-carbon double bond and a hydrophobic moiety but not containing a carboxylic acid group, and optionally a third monomer containing a carbon-carbon double bond and a hydrophilic moiety but not containing a carboxylic acid group;

[0231] A polyaromatic ring polymer (hereinafter, cardo adhesive) having a backbone structure and including a carboxylic acid group (-COOH), in which two aromatic rings are bonded to a quaternary carbon atom that is a constituent atom of another cyclic portion of the backbone; or

[0232] Their combination.

[0233] In the embodiments, the dispersant may include a first monomer, a second monomer, and optionally a third monomer.

[0234] The carboxylic acid-containing compound may have an acid value greater than or equal to about 50 mg KOH per gram (mg KOH / g). In the examples, the acid value of the carboxylic acid-containing compound may be greater than or equal to about 60 mg KOH / g, greater than or equal to about 70 mg KOH / g, greater than or equal to about 80 mg KOH / g, greater than or equal to about 90 mg KOH / g, greater than or equal to about 100 mg KOH / g, greater than or equal to about 110 mg KOH / g, greater than or equal to about 120 mg KOH / g, greater than or equal to about 125 mg KOH / g, or greater than or equal to about 130 mg KOH / g. The acid value of a carboxylic acid group compound may be less than or equal to about 250 mg KOH / g, for example, less than or equal to about 240 mg KOH / g, less than or equal to about 230 mg KOH / g, less than or equal to about 220 mg KOH / g, less than or equal to about 210 mg KOH / g, less than or equal to about 200 mg KOH / g, less than or equal to about 190 mg KOH / g, less than or equal to about 180 mg KOH / g, or less than or equal to about 160 mg KOH / g, but is not limited thereto.

[0235] Compounds containing a carboxylic acid group may have a molecular weight (or weight-average molecular weight) greater than or equal to about 400 g / mol, greater than or equal to about 500 g / mol, greater than or equal to about 1000 g / mol, greater than or equal to about 2000 g / mol, greater than or equal to about 3000 g / mol, or greater than or equal to about 5000 g / mol. Compounds containing a carboxylic acid group may have a weight-average molecular weight less than or equal to about 100,000 g / mol (e.g., less than or equal to about 50,000 g / mol).

[0236] In the composition or complex, based on the total weight or total solids content of the composition, the amount of dispersant (e.g., binder polymer) may be greater than or equal to about 0.5 wt%, for example, greater than or equal to about 1 wt%, greater than or equal to about 5 wt%, greater than or equal to about 10 wt%, greater than or equal to about 15 wt%, or greater than or equal to about 20 wt%, but is not limited thereto. Based on the total weight or total solids content of the composition (or complex, hereinafter, "composition"), the amount of dispersant (e.g., binder polymer) may be less than or equal to about 55 wt%, less than or equal to about 35 wt%, for example, less than or equal to about 33 wt%, or less than or equal to about 30 wt%.

[0237] In the composition or liquid carrier, a polymerizable (e.g., photopolymerizable) monomer comprising a carbon-carbon double bond (hereinafter, may be referred to as "monomer") may include (e.g., photopolymerizable) (meth)acryloyl (i.e., (meth)acryloyl-containing) monomer. The monomer may be a precursor to an insulating polymer.

[0238] Based on the total weight or total solids content of the composition, the amount of monomer may be greater than or equal to about 0.5 wt%, for example, greater than or equal to about 1 wt%, greater than or equal to about 2 wt%, greater than or equal to about 3 wt%, greater than or equal to about 5 wt%, or greater than or equal to about 10 wt%. Based on the total weight or total solids content of the composition, the amount of monomer may be less than or equal to about 30 wt%, for example, less than or equal to about 28 wt%, less than or equal to about 25 wt%, less than or equal to about 23 wt%, less than or equal to about 20 wt%, less than or equal to about 18 wt%, less than or equal to about 17 wt%, less than or equal to about 16 wt%, or less than or equal to about 15 wt%.

[0239] The (photo)initiator included in the composition is a compound that initiates the (photo)polymerization of the monomers in the aforementioned composition. An initiator is a compound that promotes a free radical reaction (e.g., free radical polymerization of monomers) by generating free radical chemicals under mild conditions (e.g., by heat or light). The initiator can be a thermal initiator or a photoinitiator. There are no particular limitations on the initiator, and it can be appropriately selected.

[0240] In the composition, the amount of initiator can be appropriately adjusted considering the type and amount of polymerizable monomers. In the examples, based on the total weight (or total solids content) of the composition, the amount of initiator can be greater than or equal to about 0.01 wt%, for example, greater than or equal to about 1 wt% and less than or equal to about 10 wt%, for example, less than or equal to about 9 wt%, less than or equal to about 8 wt%, less than or equal to about 7 wt%, less than or equal to about 6 wt%, or less than or equal to about 5 wt%, but is not limited thereto.

[0241] The composition (or complex) may also include, for example, a thiol compound (polyfunctional or monofunctional) having, for example, at least one thiol group at the end (or a portion derived from the reaction between the thiol compound and the carbon-carbon double bond portion, for example, a sulfide group), fine particles of metal oxide, or combinations thereof.

[0242] The fine particles of metal oxide may include TiO2, SiO2, BaTiO3, Ba2TiO4, ZnO, or combinations thereof. In the composition, based on the total weight (or total solids content) of the composition, the amount of fine particles of metal oxide may be greater than or equal to about 1 wt%, greater than or equal to about 2 wt%, greater than or equal to about 3 wt%, greater than or equal to about 4 wt%, greater than or equal to about 5 wt%, or greater than or equal to about 10 wt% and less than or equal to about 50 wt%, less than or equal to about 40 wt%, less than or equal to about 30 wt%, less than or equal to about 25 wt%, less than or equal to about 20 wt%, less than or equal to about 15 wt%, less than or equal to about 10 wt%, less than or equal to about 5 wt%, or less than or equal to about 3 wt%. The fine particles of metal oxide may be non-emissive (e.g., non-luminescent). The metal oxide may include oxides of metals or metalloids.

[0243] The metal oxide particles can have a suitably chosen diameter without particular limitation. The diameter of the metal oxide particles can be greater than or equal to about 100 nm, for example, greater than or equal to about 150 nm, or greater than or equal to about 200 nm and less than or equal to about 1,000 nm, or less than or equal to about 800 nm.

[0244] (Multi)thiol compounds can be dithiols, trithiols, tetrathiols, or combinations thereof. In the examples, the thiol compound can be diol di-3-mercaptopropionate (e.g., ethylene glycol di-3-mercaptopropionate), diol dimercaptoacetate (e.g., ethylene glycol dimercaptoacetate), trimethylolpropane-tris(3-mercaptopropionate), pentaerythritol tetra(3-mercaptopropionate), pentaerythritol tetra(2-mercaptoacetate), 1,6-hexanedithiol, 1,3-propanedithiol, 1,2-ethylenedithiol, polyethylene glycol dithiol comprising one to ten ethylene glycol repeating units, or combinations thereof.

[0245] Based on the total weight or total solids content of the composition, the amount of the thiol compound may be less than or equal to about 50 wt%, less than or equal to about 40 wt%, less than or equal to about 30 wt%, less than or equal to about 20 wt%, less than or equal to about 10 wt%, less than or equal to about 9 wt%, less than or equal to about 8 wt%, less than or equal to about 7 wt%, less than or equal to about 6 wt%, or less than or equal to about 5 wt%. Based on the total weight or total solids content of the composition, the amount of the thiol compound may be greater than or equal to about 0.1 wt%, for example, greater than or equal to about 0.5 wt%, greater than or equal to about 1 wt%, greater than or equal to about 5 wt%, greater than or equal to about 10 wt%, greater than or equal to about 15 wt%, greater than or equal to about 20 wt%, or greater than or equal to about 25 wt%.

[0246] The composition or liquid carrier may also include an organic solvent. The composition or liquid carrier may not include an organic solvent. If present, there are no particular limitations on the type of organic solvent that can be used. The type and amount of solvent can be appropriately selected by taking into account the aforementioned main components (i.e., the luminescent nanostructures, dispersants, photopolymerizable monomers, photoinitiators, and, if used, thiols) and the type and amount of additives described herein. In addition to the desired amount of solids content (non-volatile components), the composition may also include a residual amount of solvent.

[0247] In the embodiments, examples of solvents may include, but are not limited to: ethyl 3-ethoxypropionate; ethylene glycol series, such as ethylene glycol, diethylene glycol, or polyethylene glycol; ethylene glycol ether series, such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, ethylene glycol diethyl ether, or diethylene glycol dimethyl ether; ethylene glycol ether acetate series, such as ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, or diethylene glycol monobutyl ether acetate; propylene glycol series, such as propylene glycol; propylene glycol ether series, such as propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, propylene glycol diethyl ether, or dipropylene glycol diethyl ether; propylene glycol ether acetate series, such as propylene glycol monomethyl ether acetate or dipropylene glycol monoethyl ether... Diethyl ether acetate; amide series, such as N-methylpyrrolidone, dimethylformamide, or dimethylacetamide; ketone series, such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), or cyclohexanone; petroleum product series, such as toluene, xylene, or solvent naphtha; ester series, such as ethyl acetate, propyl acetate, butyl acetate, cyclohexyl acetate, or ethyl lactate; ether series, such as diethyl ether, dipropyl ether, or dibutyl ether; chloroform, C1 to C40 aliphatic hydrocarbons (e.g., alkanes, alkenes, or alkynes), halogen (e.g., chlorine) substituted C1 to C40 aliphatic hydrocarbons (e.g., dichloroethane, chloroform, etc.), C6 to C40 aromatic hydrocarbons (e.g., toluene, xylene, etc.), halogen (e.g., chlorine) substituted C6 to C40 aromatic hydrocarbons; or combinations thereof.

[0248] If desired, in addition to the foregoing components, the composition (or complex) may also include various additives such as light diffusers, leveling agents, or coupling agents. Components (adhesives, monomers, solvents, additives, thiols, cardo adhesives, etc.) included in the compositions (or complexes) of the examples may be suitably selected, and for details, reference may be made to, for example, what is described in US-2017-0052444-A1.

[0249] In the embodiments, the composition can be prepared by a method comprising: preparing a dispersion comprising the aforementioned luminescent nanostructures, a dispersant, and a solvent; and mixing the dispersion with an initiator, a polymerizable monomer (e.g., an acryloyl monomer), an optional thiol compound, optional metal oxide particles, and optional additives. Each of the aforementioned components may be mixed sequentially or simultaneously, but the mixing order is not particularly limited.

[0250] The composition can be provided as a color conversion layer (or a patterned film of a composite) by (e.g., free radical) polymerization. The composition according to embodiments can be a photoresist composition comprising a luminescent nanostructure suitable for photolithography.

[0251] In embodiments, color conversion layers or patterned luminescent nanostructure composite films can be fabricated using a photoresist composition. This method may include:

[0252] A film of the composition is formed on a substrate (S1);

[0253] Optional pre-baked (or “pre-baked”) membrane (S2);

[0254] Exposing selected regions of the membrane to light (e.g., wavelengths less than or equal to about 400 nm) (S3); and

[0255] The exposed film is developed with an alkaline developer to obtain a pattern including a luminescent nanostructure-polymer composite (S4).

[0256] Reference Figure 2A Describe non-restrictive methods for forming patterns.

[0257] The composition can be coated onto a substrate to a predetermined thickness (S1) using appropriate methods such as spin coating or slot coating. Optionally, the film formed can be pre-baked (PRB) (S2). Pre-baking can be performed by selecting appropriate conditions such as temperature, time, and atmosphere.

[0258] The formed (or optionally pre-baked) film is exposed to light of a predetermined wavelength under a mask (e.g., a photomask) with a predetermined pattern (S3). The wavelength and intensity of the light can be selected by considering the initiator (e.g., a photoinitiator), the amount of the initiator (e.g., a photoinitiator), quantum dots, the amount of quantum dots, etc. Figure 2A In this context, BM represents the black matrix.

[0259] The exposed film is treated with an alkaline developer (e.g., immersion or spraying) to dissolve the unexposed areas and obtain the desired pattern. The obtained pattern may optionally be post-baked (or “post-baked”) at about 150°C to about 230°C for a predetermined time (e.g., greater than or equal to about 10 minutes or greater than or equal to about 20 minutes) to improve the crack resistance and solvent resistance of the pattern (S5).

[0260] In embodiments where the color conversion layer or luminescent nanostructure-polymer composite pattern has multiple repeating portions, a composite with a desired pattern can be obtained by: preparing luminescent nanostructures having desired photoluminescent properties (e.g., photoluminescence peak wavelength) to form each repeating portion (e.g., a red-emitting luminescent nanostructure, a green-emitting luminescent nanostructure, or optionally a blue-emitting luminescent nanostructure) and forming the repeating pattern of each composite an appropriate number of times (e.g., two or more times, or three or more times) (S6). For example, the luminescent nanostructure-polymer composite may have (e.g., configured) a pattern comprising at least two repeating color portions (e.g., RGB portions). The luminescent nanostructure-polymer composite pattern can be used as a photoluminescent color filter or color conversion layer in a display device or color conversion panel.

[0261] Color conversion layers or luminescent nanostructure composite patterns can be formed using ink compositions configured to form patterns via inkjet printing. (See reference...) Figure 2B The method includes preparing or having already provided an ink composition; obtaining a substrate including, for example, a pattern of electrodes and pixel regions optionally formed by dikes; depositing the ink composition on the substrate (or pixel regions) to form a first quantum dot layer (or a first repeating portion); and depositing the ink composition on the substrate (or pixel regions) to form a second quantum dot layer (or a second repeating portion). The formation of the first quantum dot layer and the second quantum dot layer can be performed simultaneously or sequentially.

[0262] The deposition of the ink composition can be performed using a suitable droplet ejection system (such as an inkjet printer or nozzle printing system) (e.g., having an ink reservoir and, for example, at least one printhead). The deposited ink composition can be heated to remove the solvent and optionally polymerized, thereby providing a (first or second) quantum dot layer. This method can provide highly precise luminescent nanostructure-polymer composite films or patterns in a relatively efficient manner and within a relatively short time.

[0263] In embodiments, the first composite (e.g., a luminescent nanostructure polymer composite) comprises a matrix (e.g., a polymer matrix) and the aforementioned luminescent nanostructure dispersed within the matrix. The first composite may also comprise fine particles of metal oxide dispersed within the matrix. The (polymer) matrix may comprise a linear polymer, a crosslinked polymer, or a combination thereof. The crosslinked polymer may comprise a thiolene resin, crosslinked poly(meth)acrylate, crosslinked polyurethane, crosslinked epoxy resin, crosslinked vinyl polymer, crosslinked silicone resin, or a combination thereof. The linear polymer may comprise repeating units derived from carbon-carbon unsaturated bonds (e.g., carbon-carbon double bonds). The repeating units may comprise carboxylic acid groups. The linear polymer may comprise ethylene repeating units.

[0264] In the first composite of the embodiments, the amounts of the plurality of luminescent nanostructures and / or metal oxide particles are as described herein. In the embodiments, based on the total weight of the composite, the amount of matrix may be greater than or equal to about 10 wt%, greater than or equal to about 20 wt%, greater than or equal to about 30 wt%, greater than or equal to about 40 wt%, greater than or equal to about 50 wt%, or greater than or equal to about 60 wt%. In the embodiments, based on the total weight of the composite, the amount of matrix may be less than or equal to about 90 wt%, less than or equal to about 80 wt%, less than or equal to about 70 wt%, less than or equal to about 60 wt%, less than or equal to about 50 wt%, or less than or equal to about 40 wt%.

[0265] In the composite, based on the total weight of the composite, the total amount of quantum dots and / or metal oxide particles can be greater than or equal to about 10 wt%, greater than or equal to about 20 wt%, greater than or equal to about 30 wt%, greater than or equal to about 40 wt%, greater than or equal to about 50 wt%, or greater than or equal to about 60 wt%. In the composite, based on the total weight of the composite, the total amount of luminescent nanostructures and / or metal oxide particles can be less than or equal to about 90 wt%, less than or equal to about 80 wt%, less than or equal to about 70 wt%, less than or equal to about 60 wt%, less than or equal to about 50 wt%, or less than or equal to about 40 wt%.

[0266] The luminescent nanostructure of the embodiment can exhibit a positive differential coefficient at a wavelength of about 450 nm, and the first composite of the embodiment can also simultaneously exhibit improved absorption of blue incident light and relatively high luminescence efficiency.

[0267] The polymer matrix may include a dispersant (e.g., a binder monomer or polymer comprising a carboxylic acid group), a polymer of a polymerizable monomer having a carbon-carbon double bond (e.g., at least one, at least two, at least three, at least four, or at least five) (e.g., an insulating polymer), a polymer of an optional polymerizable monomer and a thiol compound (e.g., a polythiol compound, such as having at least two thiol groups at its end), or a combination thereof. In embodiments, the polymer matrix may include crosslinked polymers, linear polymers, or combinations thereof. The polymer matrix may not include conjugated polymers (except for cardo resins). The polymer matrix may include conjugated polymers.

[0268] Crosslinked polymers may include thiolene resins, crosslinked poly(meth)acrylates, crosslinked polyurethanes, crosslinked epoxy resins, crosslinked vinyl polymers, crosslinked silicone resins, or combinations thereof. In embodiments, the crosslinked polymer may be a polymer of polymerizable monomers and optionally polythiol compounds.

[0269] Linear polymers may include repeating units derived from carbon-carbon unsaturated bonds (e.g., carbon-carbon double bonds). Repeating units may include carboxylic acid groups. Linear polymers may include ethylene repeating units.

[0270] Repeating units containing a carboxylic acid group may include units derived from monomers comprising a carboxylic acid group and a carbon-carbon double bond, units derived from monomers having a dianhydride moiety, or combinations thereof.

[0271] The polymer matrix may include compounds containing carboxylic acid groups (e.g., adhesives, adhesive polymers, or dispersants) (e.g., dispersions or adhesives for quantum dots).

[0272] The first composite or its film or its pattern may have a thickness of, for example, less than or equal to about 30 micrometers (μm), for example, less than or equal to about 25 μm, less than or equal to about 20 μm, less than or equal to about 15 μm, less than or equal to about 10 μm, less than or equal to about 8 μm, or less than or equal to about 7 μm and greater than or equal to about 2 μm, for example, greater than or equal to about 3 μm, greater than or equal to about 3.5 μm, greater than or equal to about 4 μm, greater than or equal to about 5 μm, greater than or equal to about 6 μm, greater than or equal to about 7 μm, greater than or equal to about 8 μm, greater than or equal to about 9 μm, or greater than or equal to about 10 μm.

[0273] Luminescent nanostructures, or composites (patterns) including luminescent nanostructures, or color conversion panels including composites (or patterns), can be included in electronic devices. Such electronic devices can include, but are not limited to, display devices, light-emitting diodes (LEDs), organic light-emitting diodes (OLEDs), quantum dot LEDs, sensors, solar cells, imaging sensors, photodetectors, or liquid crystal displays. The aforementioned luminescent nanostructures can be included in electronic devices. Such electronic devices can include, but are not limited to, portable terminal devices, monitors, laptop personal computers (PCs), televisions, electronic displays, cameras, automobiles, etc. Electronic devices can be portable terminal devices, monitors, laptop PCs, or televisions that include quantum dot display devices (or luminescent devices). Electronic devices can be cameras or portable terminal devices that include image sensors containing luminescent nanostructures. Electronic devices can be cameras or vehicles. Electronic devices can include photodetectors containing luminescent nanostructures.

[0274] In embodiments, the electronic device or display device (e.g., a display panel) may further include a color conversion panel and an optional light source or emitting panel. In an embodiment, the display panel 1000 includes an emitting panel (or light source) 40, a color conversion panel 50, and a light transmission layer 60 disposed between the emitting panel and the color conversion panel. The color conversion panel may further include a substrate, and the color conversion layer may be disposed on the surface of the substrate (see...). Figure 3A and Figure 4 ).

[0275] If present, the light source or light-emitting panel 40 can be configured to provide incident light to the light-emitting element. The incident light may have a peak emission wavelength in the range of about 440 nm, for example, about 450 nm, about 500 nm, or about 520 nm and less than or equal to about 580 nm, for example, less than or equal to about 480 nm, less than or equal to about 470 nm, or less than or equal to about 460 nm.

[0276] In an embodiment, the device (e.g., a photoluminescent device) may include a sheet of a light-emitting nanostructure composite. See also... Figure 3BThe photoluminescent device 400 includes a backlight unit and a liquid crystal panel (LCD). The backlight unit may include a light-emitting nanostructure polymer composite sheet (QD sheet). For example, the backlight unit may include a reflector, a light guide plate (LGP), a light source (such as a blue LED), a light-emitting nanostructure polymer composite sheet (QD sheet), and optical films (such as prisms and dual brightness enhancement films (DBEF)). The LCD panel may be disposed on the backlight unit and may have a structure including thin-film transistors (TFTs), liquid crystal (LC), and a color filter between two polarizers (Pol). The light-emitting nanostructure polymer composite sheet (QD sheet) may include light-emitting nanostructures that emit red light by absorbing light from the light source and light-emitting nanostructures that emit green light by absorbing light from the light source. Blue light from the light source can pass through the light-emitting nanostructure polymer composite sheet, combine with the red and green light emitted from the light-emitting nanostructures, and be converted into white light. The white light can be separated into blue, green, and red light by the color filter in the LCD panel and can be emitted to the outside in each pixel.

[0277] The color conversion panel may also include a base, and the color conversion layer may be placed on the base.

[0278] In embodiments, the color conversion layer or color conversion panel may be disposed on the front surface (e.g., a light extraction surface) of a device (light-emitting device or display device) in the form of a patterned film of a light-emitting nanostructure (or a composite thereof). The patterned film may include repeating portions configured to emit desired light. The repeating portions may include a first portion. The first portion may be a red light-emitting portion. The repeating portions may include a second portion. The second portion may include a green light-emitting portion. The repeating portions may include a third portion. The third portion may be a portion that emits or transmits blue light. Details of the first, second, and third portions are described herein.

[0279] The light-emitting panel or light source can be an element that emits incident light. The incident light or excitation light can include blue light and optionally green light. The light source can include an LED. The light source can include an organic LED (OLED). On the front surfaces (light-emitting surfaces) of the first and second portions, optical elements (e.g., a blue light (and optionally green light) blocking layer or a first filter, as described herein, can be disposed. When the light source includes an organic light-emitting diode that emits blue light and an organic light-emitting diode that emits green light, a green light removal filter can also be disposed on the third portion that transmits blue light.

[0280] The light-emitting panel or light source may include a plurality of light-emitting units corresponding to the first portion and the second portion, respectively, and the light-emitting units may include a first electrode and a second electrode facing each other, and an (organic) electroluminescent layer between the first electrode and the second electrode. The electroluminescent layer may include an organic light-emitting material. For example, each light-emitting unit of the light source may include an electroluminescent device (e.g., an organic light-emitting diode (OLED)) configured to emit light of a predetermined wavelength (e.g., blue light, green light, or a combination thereof). There are no particular limitations on the structure and materials of the electroluminescent device and the organic light-emitting diode (OLED).

[0281] The display panel and color conversion panel will be described below with reference to the accompanying drawings.

[0282] Figure 3A This is a perspective view of an embodiment of a display panel constructed according to the principles of the present invention. Figure 4 yes Figure 3A A cross-sectional view of the display panel. (Refer to...) Figure 3A and Figure 4 According to an embodiment, the display panel 1000 includes a light-emitting panel 40, a color conversion panel 50, a light-transmitting layer (or light-transmitting panel) 60 disposed between the light-emitting panel 40 and the color conversion panel 50, and an adhesive material 70 for bonding the light-emitting panel 40 and the color conversion panel 50.

[0283] Both the light-emitting panel 40 and the color-converting panel 50 have surfaces facing each other (i.e., the two respective panels face each other), and a light-transmitting layer 60 is disposed between the two panels. The color-converting panel 50 is positioned such that light emitted from, for example, the light-emitting panel 40 illuminates the light-transmitting panel 60. An adhesive material 70 is disposed along the edges of the light-emitting panel 40 and the color-converting panel 50, and may be, for example, a sealing material.

[0284] Figure 5 This is a plan view of an embodiment of the pixel arrangement of the display panel. (Refer to...) Figure 5 The display panel 1000 includes a display area 1000D for displaying images and a non-display area 1000P located in the peripheral area of ​​the display area 1000D and provided with adhesive material 70.

[0285] Display area 1000D includes a plurality of pixels PX arranged along rows (e.g., the x-direction) and columns (e.g., the y-direction), and each representative pixel PX may include a plurality of sub-pixels PX1, PX2, and PX3 that represent (e.g., display) different colors from each other. An embodiment is illustrated by a structure in which three sub-pixels PX1, PX2, and PX3 are configured to provide pixels. The embodiment may also include additional sub-pixels such as white sub-pixels, and may also include at least one sub-pixel that represents (e.g., display) the same color. The plurality of pixels PX may be aligned, for example, in a Bayer matrix, a matrix sold under the trade name PenTile, a diamond (or cube) matrix, or a combination thereof.

[0286] Subpixels PX1, PX2, and PX3 can represent (e.g., display) the three primary colors or combinations of the three primary colors, for example, they can represent (e.g., display) red, green, blue, or combinations thereof. For example, the first subpixel PX1 can represent (e.g., display) red, the second subpixel PX2 can represent (e.g., display) green, and the third subpixel PX3 can represent (e.g., display) blue.

[0287] In the accompanying drawings, all subpixels are shown to have the same size, but at least one subpixel may be larger or smaller than the other subpixels. In the accompanying drawings, all subpixels are shown to have the same shape, but at least one subpixel may have a different shape than the other subpixels.

[0288] Figure 6A This is a schematic cross-sectional view of a display device according to an embodiment. Figure 6B This is a schematic cross-sectional view of a display device according to an embodiment. (Refer to...) Figure 6A and Figure 6B The light source includes an organic light-emitting diode (OLED) that emits blue (B) light (and optionally green light to provide incident light of mixed colors). The OLED may include at least two pixel electrodes 90a, 90b, 90c formed on a substrate 100, pixel defining layers 150a, 150b formed between adjacent pixel electrodes 90a, 90b, 90c, organic light-emitting layers 140a, 140b, 140c formed on each pixel electrode 90a, 90b, 90c, and a common electrode layer 130 formed on the organic light-emitting layers 140a, 140b, 140c. Thin-film transistors and a substrate may be disposed below the OLED. The pixel regions of the OLED may be configured to correspond to the first, second, and third portions.

[0289] A stacked structure comprising a light-emitting nanostructure composite pattern 170 (e.g., a first portion 11 or R comprising a red-emitting nanostructure, a second portion 21 or G comprising a green-emitting nanostructure, and a third portion 31 or B comprising or excluding a light-emitting nanostructure (e.g., a blue-emitting nanostructure)) and a substrate 240 can be disposed on a light source. Blue light emitted from the light source enters the first and second portions and can emit red and green light, respectively. Blue light emitted from the light source can pass through the third portion. As desired, an element configured to block excitation light (a first filter 160 or an excitation light blocking layer) can be disposed between the light-emitting nanostructure composite layers R and G and the substrate. When the excitation light includes both blue and green light, a green light blocking filter (not shown) can be added to the third portion. The first filter or excitation light blocking layer will be described in more detail here.

[0290] Such a display device can be manufactured by separately fabricating the aforementioned stacked structure and an LED or OLED (e.g., emitting blue light), and then combining the stacked structure and the LED or OLED. Alternatively, the display device can be manufactured by directly forming a pattern of light-emitting nanostructure composites on the LED or OLED.

[0291] In color conversion panels or display devices, the substrate can be a substrate comprising an insulating material. The substrate may include: glass; various polymers such as polyesters (e.g., polyethylene terephthalate (PET), polyethylene naphthalate (PEN), etc.), polycarbonate and polyacrylate, polysiloxanes (e.g., polydimethylsiloxane (PDMS)); inorganic materials such as Al₂O₃ or ZnO; or combinations thereof, but not limited thereto. The thickness of the substrate can be suitably selected based on the substrate material, but there are no particular limitations. The substrate can be flexible. For light emitted from the luminescent nanostructures, the substrate may have a transmittance 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 80%, or greater than or equal to about 90%.

[0292] A wiring layer, including thin-film transistors, is formed on a substrate. The wiring layer may further include gate lines, sustaining voltage lines, a gate insulating layer, data lines, a source, a drain, a semiconductor layer, a protective layer, etc. The detailed structure of the wiring layer can vary depending on the embodiment. The gate lines and sustaining voltage lines are electrically isolated from each other, and the data lines are insulated and pass through the gate lines and sustaining voltage lines. The gate, source, and drain form the control terminal, input terminal, and output terminal of the thin-film transistor, respectively. The drain is electrically connected to the pixel electrode, which will be described herein.

[0293] Pixel electrodes can be used as electrodes (e.g., anodes) in display devices. Pixel electrodes can be formed from transparent conductive materials (such as indium tin oxide (ITO) or indium zinc oxide (IZO)). Pixel electrodes can also be formed from materials with light-blocking properties (such as gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), cobalt (Co), copper (Cu), palladium (Pd), or titanium (Ti)). Pixel electrodes can have a two-layer structure in which a transparent conductive material and a material with light-blocking properties are sequentially stacked.

[0294] Between two adjacent pixel electrodes, a pixel defining layer (PDL) is stacked at the end of the pixel electrode to divide the pixel electrode into pixel units. The pixel defining layer is an insulating layer that can electrically block at least two pixel electrodes.

[0295] A pixel defining layer covers a portion of the upper surface of the pixel electrode, and the remaining area of ​​the pixel electrode not covered by the pixel defining layer can provide an opening. An organic light-emitting layer, which will be described herein, can be formed in the area defined by the opening.

[0296] The organic light-emitting layer defines each pixel region through the aforementioned pixel electrode and pixel defining layer. In other words, a pixel region can be defined as a region having an organic light-emitting unit layer, which is in contact with a pixel electrode defined by the pixel defining layer. In the display device according to the embodiment, the organic light-emitting layer can be defined as a first pixel region, a second pixel region, and a third pixel region, each pixel region being separated from each other by the pixel defining layer and leaving a predetermined interval.

[0297] In embodiments, the organic light-emitting layer can emit a third light belonging to either the visible light region or the ultraviolet (UV) region. The first to third pixel regions of the organic light-emitting layer can emit the third light. In embodiments, the third light can be light with the highest energy in the visible light region, for example, it can be blue light (and optionally green light). When all pixel regions of the organic light-emitting layer are designed to emit the same light, each pixel region of the organic light-emitting layer can be entirely formed of the same or similar materials, or can exhibit (e.g., display) the same or similar properties. Therefore, the process for forming the organic light-emitting layer can be simplified, and the display device can be easily applied to large-scale / large-area processing (e.g., manufactured by large-scale / large-area processing). However, the organic light-emitting layer according to embodiments is not necessarily limited to this, but the organic light-emitting layer can be designed to emit at least two different lights, for example, at least two different colors of light.

[0298] The organic light-emitting layer includes an organic light-emitting unit layer in each pixel region. In addition to the light-emitting layer, each organic light-emitting unit layer may also include auxiliary layers (e.g., hole injection layer, hole transport layer, electron transport layer, etc.).

[0299] The common electrode can be used as the cathode of a display device. The common electrode can be formed from a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The common electrode can be formed on and integrated with the organic light-emitting layer.

[0300] A planarization layer or passivation layer (not shown) may be formed on the common electrode. The planarization layer may include an insulating material (e.g., transparent) to ensure electrical insulation from the common electrode.

[0301] In an embodiment, the display device may further include a lower substrate, a polarizer disposed below the lower substrate, and a liquid crystal layer disposed between the laminated structure and the lower substrate, wherein a photoluminescent layer (i.e., an emissive layer) may be configured to face the liquid crystal layer. The display device may also include a polarizer located between the liquid crystal layer and the emissive layer. The light source may further include an LED, and, if desired, may also include a light guide plate.

[0302] The accompanying drawings illustrate a non-limiting example of a display device (e.g., a liquid crystal display device) according to an embodiment. Figure 7 This is a schematic cross-sectional view showing a liquid crystal display device according to an embodiment. (Refer to...) Figure 7 The display device of the embodiment includes a liquid crystal panel 200, a polarizing plate 300 disposed below the liquid crystal panel 200, and a backlight unit disposed below the polarizing plate 300.

[0303] The liquid crystal panel 200 includes a lower substrate 210, a stacked structure, and a liquid crystal layer 220 disposed between the stacked structure and the lower substrate. The stacked structure includes a transparent substrate 240, a first filter layer 310, a photoluminescent layer 230 including a pattern of a light-emitting nanostructure polymer composite, and a second filter layer 311.

[0304] The lower substrate 210, referred to as the array substrate, may be a transparent insulating material substrate. The substrate is the same as described herein. A wiring board 211 is disposed on the upper surface of the lower substrate 210. The wiring board 211 may include, but is not limited to, multiple gate wirings (not shown) and data wirings (not shown) defining pixel regions, thin-film transistors positioned adjacent to the intersection regions of the gate wirings and data wirings, and pixel electrodes for each pixel region. The details of such a wiring board are not particularly limited.

[0305] The liquid crystal panel 200 may include alignment layers 221 on and below the liquid crystal layer 220 to initially align the liquid crystal material included therein. Details of the liquid crystal layer and alignment layer (e.g., liquid crystal material, alignment layer material, method of forming the liquid crystal layer, thickness of the liquid crystal layer, etc.) are not particularly limited.

[0306] The lower polarizer 300 is disposed below the lower substrate 210. The material and structure of the polarizer 300 are not particularly limited. (For example, a backlight unit emitting blue light) can be disposed below the polarizer 300. The upper optical element or polarizer 300 can be disposed between the liquid crystal layer 220 and the transparent substrate 240, but is not limited thereto. For example, the upper polarizer can be disposed between the liquid crystal layer 220 and the photoluminescent layer 230. The polarizer can be any suitable polarizer used in a liquid crystal display device. The polarizer can be TAC (triacetyl cellulose) with a thickness of less than or equal to about 200 μm, but is not limited thereto. In an embodiment, the upper optical element can be a coating that controls the refractive index but does not have a polarizing function.

[0307] The backlight unit includes a light source 110. The light source 110 can emit blue light or white light. The light source 110 may include, but is not limited to, a blue LED, a white LED, a white OLED, or a combination thereof.

[0308] The backlight unit may also include a light guide plate 120. In embodiments, the backlight unit may be edge-lit. For example, the backlight unit may include a reflector (not shown), a light guide plate (not shown) disposed on the reflector and providing a planar light source to the liquid crystal panel 200, at least one optical sheet (not shown) (e.g., a diffuser, prism sheet, etc.) located on the light guide plate, or combinations thereof, but is not limited thereto. The backlight unit may not include a light guide plate. In embodiments, the backlight unit may be direct-lit. For example, the backlight unit may have a reflector (not shown) and may have a plurality of fluorescent lamps disposed at regular intervals on the reflector, or may have an LED operating substrate on which a plurality of light-emitting diodes may be disposed, a diffuser located on the LED operating substrate, and optionally, at least one optical sheet. The details of such a backlight unit (e.g., each component of the light-emitting diodes, fluorescent lamps, light guide plate, various optical sheets, and reflector) are not particularly limited.

[0309] A black matrix 241 is disposed beneath a transparent substrate 240 and has openings, concealing gate lines, data lines, and thin-film transistors of a wiring board located on the lower substrate. For example, the black matrix 241 may have a grid shape. A photoluminescent layer 230 is disposed within the openings of the black matrix 241 and has a pattern of light-emitting nanostructure composites, the pattern comprising a first portion (R) configured to emit a first light (e.g., red light), a second portion (G) configured to emit a second light (e.g., green light), and a third portion (B) configured to emit / transmit, for example, blue light. If desired, the photoluminescent layer 230 may also include, for example, at least one fourth portion. The fourth portion may include a light-emitting nanostructure that emits light of a different color (e.g., cyan, magenta, and yellow light) than the light emitted from the first to the third portions.

[0310] In the photoluminescent layer 230, the patterned portions can be repeated correspondingly to the pixel regions formed on the lower substrate 210. A transparent common electrode 231 can be disposed on the photoluminescent color filter layer.

[0311] The third part (B), configured to emit / transmit blue light, can be a transparent color filter that does not alter the emission spectrum of the light source. Blue light emitted from the backlight unit can enter in a polarized state and pass through the polarizer and liquid crystal layer as is. If desired, the third part can include a light-emitting nanostructure that emits blue light.

[0312] As described herein, the display device or light-emitting device of the embodiment may, if desired, also have an excitation light blocking layer or a first filter layer (hereinafter referred to as the first filter layer). The first filter layer may be disposed between the bottom surface of the first portion (R) and the second portion (G) and the substrate (e.g., upper substrate 240) or disposed on the upper surface of the substrate. The first filter layer 310 may be a sheet having openings in the region corresponding to the blue pixel region (third portion), and thus formed in the region corresponding to the first portion and the second portion. Figure 6A , Figure 6B and Figure 7 As shown, the first filter layer can be disposed at locations other than those overlapping with the third portion and integrally formed therewith, but is not limited thereto. In an embodiment, at least two first filter layers can be configured to leave space at each location overlapping with the first and second portions. When the light source includes a green light emitting element, a green light blocking layer can be disposed on the third portion. In an embodiment, the light source may also include a green light emitting element, and a green light blocking (or removal) element may be disposed on the third region, which will be described below.

[0313] The first filter layer can block (e.g., absorb) or substantially block light having a predetermined wavelength region, for example, in the visible light region, and can transmit light in other wavelength regions. For example, the first filter layer can block blue light (or green light) and can transmit light other than blue light (or green light). The first filter layer can transmit, for example, green light, red light, and / or yellow light as a mixture of green and red light. The first filter layer can transmit blue light and can block or cut off green light, and can be disposed on a third region (e.g., a blue light emitting region).

[0314] The first filter layer can substantially block the excitation light and transmit light within the desired wavelength range. For light within the desired wavelength range, the transmittance of the first filter layer can be greater than or equal to about 70%, greater than or equal to about 80%, greater than or equal to about 90%, or even about 100%.

[0315] A first filter layer configured to selectively transmit red light can be disposed at a position superimposed on the red light emitting portion, and a first filter layer configured to selectively transmit green light can be disposed at a position superimposed on the green light emitting portion. The first filter layer may include: a first region that blocks (e.g., absorbs) blue and red light and selectively transmits light within a predetermined range (e.g., greater than or equal to about 500 nm, greater than or equal to about 510 nm, or greater than or equal to about 515 nm and less than or equal to about 550 nm, less than or equal to about 545 nm, less than or equal to about 540 nm, less than or equal to about 535 nm, less than or equal to about 530 nm, less than or equal to about 525 nm, or less than or equal to about 520 nm); a second region that blocks (e.g., absorbs) blue and green light and selectively transmits light within a predetermined range (e.g., greater than or equal to about 600 nm, greater than or equal to about 610 nm, or greater than or equal to about 615 nm and less than or equal to about 650 nm, less than or equal to about 645 nm, less than or equal to about 640 nm, less than or equal to about 635 nm, less than or equal to about 630 nm, less than or equal to about 625 nm, or less than or equal to about 620 nm); or a combination thereof. In one embodiment, the light source may emit a mixture of blue and green light, and the first filter may further include a third region that selectively transmits blue light and blocks green light.

[0316] The first region can be positioned overlapping the green light emitting portion. The second region can be positioned overlapping the red light emitting portion. The third region can be positioned overlapping the blue light emitting portion.

[0317] The first region, the second region, and the optional third region can be optically isolated. Such a first filter layer can help improve the color purity of the display device.

[0318] The display device may further include a second filter layer (e.g., a red / green or yellow light recovery layer) 311 disposed between a photoluminescent layer and a liquid crystal layer (e.g., a photoluminescent layer and an upper polarizer, e.g., a polarizer), which transmits at least a portion of third light (excitation light) and reflects, for example, at least a portion of first light, a portion of second light, or a portion of each of the first and second light. The first light may be red light, the second light may be green light, and the third light may be blue light. For example, the second filter layer may transmit only the third light (B) in the blue light wavelength region having a wavelength region less than or equal to about 500 nm, and light in the wavelength region greater than about 500 nm (which is green light (G), yellow light, red light (R), etc.) may not pass through the second filter layer and be reflected. The reflected green and red light may pass through the first and second portions and be emitted to the outside of the display device.

[0319] The second filter layer or the first filter layer can be formed as an integral layer with a relatively flat surface.

[0320] The first filter layer may include a polymer film comprising a dye, a pigment, or a combination thereof that absorbs light at the wavelength to be blocked. The second and first filter layers may comprise monolayers with low refractive indices and may be, for example, transparent films having a refractive index of less than or equal to about 1.4, less than or equal to about 1.3, or less than or equal to about 1.2. The second or first filter layer with a low refractive index may be, for example, porous silica, porous organic materials, porous organic / inorganic composites, or combinations thereof.

[0321] The first or second filter layer may comprise multiple layers with different refractive indices. The first or second filter layer can be formed by stacking two layers with different refractive indices. For example, the first / second filter layer can be formed by alternately stacking a material with a high refractive index and a material with a low refractive index.

[0322] In the following description, embodiments are illustrated in more detail with reference to examples. However, these are exemplary embodiments of the invention, and the invention is not limited thereto.

[0323] Example

[0324] Analytical methods

[0325] 1. Ultraviolet (UV)-Vis absorption analysis

[0326] UV-Vis absorption spectroscopy analysis was performed using an Agilent Cary 5000 spectrophotometer to measure the UV-Vis absorption spectrum and the first derivative coefficient of the spectral curve at approximately 450 nm.

[0327] 2. Photoluminescence (PL) analysis

[0328] Photoluminescence (PL) spectroscopy analysis was performed using a Hitachi F-7000 spectrophotometer, and PL spectra of luminescent nanostructures and complexes were obtained.

[0329] The QY or QE (for solutions or complexes) can be measured by referring to the manual provided by the equipment manufacturer and based on knowledge known and understood in the art. The full width at half maximum (FWHM), the wavelength of the maximum emission peak, and the percentage of tailing are measured and calculated using the photoluminescence spectrum of the complex. The tailing area is measured by integrating the photoluminescence spectrum over a wavelength range greater than or equal to about 580 nm. Integration can be performed using commercially available computer programs (e.g., integration tools) or software typically supplied with or available with optical equipment, and again, programs based on knowledge known and understood in the art. Computer programs (e.g., (and / or Origin software) can draw curves from data files (e.g., files with the extension ".cvs") and can perform area calculations under the curves.

[0330] 3. Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) Analysis

[0331] The Shimadzu ICPS-8100 was used to perform inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis.

[0332] 4. Blue light absorption rate and light conversion rate of the composite material

[0333] The light dose (B) of blue incident light with a predetermined wavelength was measured using an Otsuka QE-2100 equipped with an integrating hemisphere. Subsequently, the luminescent nanostructure polymer composite was placed in the integrating hemisphere and irradiated with blue incident light to measure the green light dose (A) and blue light dose (B') from the composite.

[0334] The measurements are used to obtain the blue light absorption rate and light conversion rate according to the following equation.

[0335] Blue light absorption rate (%) = ((B-B') / B) × 100

[0336] Light conversion efficiency (%) = (A / B) × 100

[0337] 5. QY Loss Measurement

[0338] The absolute quantum yield of the complex at 80 °C and room temperature (20 °C–30 °C) was measured using an Otsuka QE-2100, and the QY loss was measured using the following equation:

[0339] QY loss (%) = [1 - (QY at 80℃ / QY at room temperature)] × 100.

[0340] See Example 1 for reference:

[0341] Zinc acetate and oleic acid were dissolved in 1-octadecene in a 250 mL reaction flask, heated under vacuum at 120 °C and cooled to room temperature to obtain a zinc oleate solution.

[0342] Indium acetate and lauric acid were added to a reaction flask, and the mixture was heated at 120°C under vacuum. After 1 hour, a nitrogen atmosphere was introduced into the reaction flask. As the temperature in the reaction flask increased to 250°C, a mixed solution of tris(trimethylsilyl)phosphine ((TMSi)3P) and trioctylphosphine was rapidly injected into the reaction flask to allow the reaction to continue. After the reaction was complete, the reaction solution was rapidly cooled to room temperature. Acetone was added to promote the formation of the first semiconductor nanocrystals (which were separated and dispersed in toluene using a centrifuge).

[0343] The amounts of indium, zinc, and phosphorus used in the preparation were in a molar ratio of 6:7:4.5. The absorption spectrum of the obtained InZnP cores exhibited a first absorption wavelength of approximately 430 nm.

[0344] Example 1

[0345] 1. Synthesis and characterization of luminescent nanostructures

[0346] Selenium and sulfur were dispersed in trioctylphosphine (TOP) to obtain Se / TOP stock solutions and S / TOP stock solutions, respectively.

[0347] In a 200 mL reaction flask, 7.2 mmol of zinc acetate and oleic acid were dissolved in trioctylamine, and the solution was evacuated at 120 °C for 10 minutes.

[0348] Subsequently, a nitrogen atmosphere was introduced into the flask, and as the solution was heated to 280°C, a toluene dispersion of the prepared first semiconductor nanocrystals, Se / TOP, and dodecyl mercaptan were injected into the flask. The reaction proceeded, and a stock solution of S / TOP was added, allowing the reaction to continue to obtain a reaction solution comprising a luminescent nanostructure, said luminescent nanostructure comprising the first semiconductor nanocrystal and a second semiconductor nanocrystal. The second semiconductor nanocrystal, comprising zinc, selenium, and sulfur, was disposed on at least a portion of the surface of the luminescent nanostructure.

[0349] The total reaction time was approximately 75 minutes, and the molar amounts of selenium (derived from the Se precursor), sulfur (derived from the sulfur precursor), and zinc (derived from the zinc precursor) added per mole of indium were controlled to achieve the final luminescent nanostructure with the composition described in Table 1. The molar ratio of dodecylthiol to S / TOP was 10:4.

[0350] Excess ethanol was added to the reaction mixture, and the luminescent nanostructures were separated by centrifugation. After centrifugation, the supernatant was discarded, and the precipitate was dried and dispersed in chloroform or toluene to obtain a solution of the luminescent nanostructures (hereinafter referred to as QD solution).

[0351] The obtained luminescent nanostructures were analyzed by ICP-AES, and the results are shown in Table 1. UV-Vis absorption spectroscopy and photoluminescence spectroscopy were performed, and the results are shown in Table 2.

[0352] 2. Fabrication of luminescent nanostructure composites and their patterns

[0353] The preparation included a chloroform dispersion of multiple luminescent nanostructures as described in Example 1, which was then mixed with a solution of a binder polymer to form a luminescent nanostructure-binder dispersion. The binder polymer solution was a quaternary copolymer of methacrylic acid, benzyl methacrylate, hydroxyethyl methacrylate, and styrene (acid value: 130 mg KOH / g, molecular weight: 8,000 g / mol) (solvent: propylene glycol monomethyl ether acetate, PGMEA, 30% by weight).

[0354] For the prepared luminescent nanostructure-binder dispersion, a hexaacrylate having the following structure (as a photopolymerizable monomer), ethylene glycol di-3-mercaptopropionate (hereinafter, 2T, as a polythiol compound), an oxime ester compound (as an initiator), TiO2 as metal oxide fine particles (light diffuser), and PGMEA (as a solvent) are added to obtain a composition.

[0355] (Ethylene glycol di-3-mercaptopropionate)

[0356] (Hexaacrylate)

[0357] in,

[0358] Based on the total solids content, the prepared composition comprises 42 wt% luminescent nanostructures, 3 wt% light diffusing agent, and a total of 55 wt% binder polymer, 2T, photopolymerizable monomers, and photoinitiator, based on the total solids content. The total solids content of the composition is approximately 25%.

[0359] The obtained composition was spin-coated onto a glass substrate at 150 rpm for 5 seconds to provide a film. The obtained film was pre-baked at 100°C (PRB). Under a mask with a predetermined pattern (e.g., square dots or stripes), the pre-baked film was exposed to light (wavelength: 365 nm, intensity: 100 mJ) for 1 second (EXP) and developed with an aqueous potassium hydroxide solution (concentration: 0.043 wt%) for 50 seconds to obtain a pattern of the luminescent nanostructured polymer composite (thickness: 6 or 10 μm).

[0360] The obtained pattern was heat-treated at 180°C for 30 minutes under a nitrogen atmosphere (POB).

[0361] The optical properties of the resulting luminescent nanostructure composite pattern were measured, and the results are shown in Table 3.

[0362] Example 2, Example 3 and Example 4

[0363] Except for changing the molar amounts of selenium and sulfur per mole of indium, luminescent nanostructures were prepared in the same manner as in Example 1 to obtain the composition and size described in Table 1.

[0364] For the prepared luminescent nanostructures, ICP-AES analysis, photoluminescence spectroscopy analysis and UV-Vis absorption spectroscopy analysis were performed, and the results are listed in Tables 1 and 2.

[0365] In addition to using the prepared luminescent nanostructures, luminescent nanostructure composite patterns were prepared in the same manner as in Example 1. The optical properties of the resulting luminescent nanostructure composite patterns were measured, and the results are shown in Table 3.

[0366] Comparison Example 1

[0367] Selenium was dispersed in trioctylphosphine to prepare a Se / TOP stock solution, and sulfur was dispersed in trioctylphosphine to prepare an S / TOP stock solution.

[0368] In a 200 mL reaction flask, zinc acetate and oleic acid were dissolved in trioctylamine, and the solution was vacuum-treated at 120 °C for 10 minutes. The reaction flask was filled with nitrogen (N2), and while the solution was heated to a reaction temperature of 320 °C, a toluene dispersion of the first semiconductor nanocrystal was added. A Se / TOP stock solution was then injected into the reaction flask several times, and the reaction proceeded until completion to form a ZnSe layer on at least a portion of the surface of the first semiconductor nanocrystal. Then, at the reaction temperature, an S / TOP stock solution was added to the reaction flask, and the reaction proceeded to form a ZnS layer on the ZnSe layer. The total reaction time was approximately 40 minutes, and the total amounts of selenium (derived from the Se precursor), sulfur (derived from the sulfur precursor), and zinc (derived from the zinc precursor) added per mole of indium were controlled such that the final luminescent nanostructure had the composition described in Table 1.

[0369] For the prepared luminescent nanostructures, ICP-AES analysis, photoluminescence spectroscopy analysis and UV-Vis absorption spectroscopy analysis were performed, and the results are listed in Tables 1 and 2.

[0370] In addition to using the prepared luminescent nanostructures, luminescent nanostructure composite patterns were prepared in the same manner as in Example 1. The optical properties of the resulting luminescent nanostructure composite patterns were measured, and the results are shown in Table 3.

[0371] Comparison Example 2

[0372] Except for changing the amount of precursor to obtain the composition and size of the luminescent nanostructures listed in Table 1 and changing the addition time and amount of S / TOP stock solution to form a ZnS layer on the ZnSeS layer, the luminescent nanostructures were prepared in the same manner as in Example 1.

[0373] For the prepared luminescent nanostructures, ICP-AES analysis, photoluminescence spectroscopy analysis and UV-Vis absorption spectroscopy analysis were performed, and the results are listed in Tables 1 and 2.

[0374] In addition to using the prepared luminescent nanostructures, luminescent nanostructure composite patterns were prepared in the same manner as in Example 1. The optical properties of the resulting luminescent nanostructure composite patterns were measured, and the results are shown in Table 3.

[0375] Compare Example 3

[0376] Except for changing the amount of precursor to obtain the composition and size of the luminescent nanostructures listed in Table 1 and changing the addition time and amount of S / TOP stock solution to form a ZnS layer on the ZnSeS layer, the luminescent nanostructures were prepared in the same manner as in Example 1.

[0377] For the prepared luminescent nanostructures, ICP-AES analysis, photoluminescence spectroscopy analysis and UV-Vis absorption spectroscopy analysis were performed, and the results are listed in Tables 1 and 2.

[0378] In addition to using the prepared luminescent nanostructures, luminescent nanostructure composite patterns were prepared in the same manner as in Example 1. The optical properties of the resulting luminescent nanostructure composite patterns were measured, and the results are shown in Table 3.

[0379] Table 1

[0380]

[0381] Table 2

[0382]

[0383] 1 st Abs: First absorption wavelength of the nanostructure

[0384] Table 3

[0385]

[0386] Experimental Example 1

[0387] 3 mL toluene dispersions were prepared, each comprising 500 μg of the luminescent nanostructure prepared in Example 1 or 500 μg of the luminescent nanostructure prepared in Comparative Example 1. 0.2 mM of benzyl violetine, an electron-scavenging compound represented by the following formula, was added to the dispersions.

[0388]

[0389] For each of the obtained dispersions, photoluminescence spectroscopy analysis was performed, and the results showed... Figure 8 middle.

[0390] Figure 8 The results confirmed that the luminescent nanostructure of Example 1 showed an improvement in QY loss compared to the luminescent nanostructure of Comparative Example 1. While not limited to the stated theory, the QY loss may be due to the phenomenon that unlocalized electrons in the first semiconductor nanocrystal may diffuse to the surface of the second semiconductor nanocrystal (at the surface of the second semiconductor nanocrystal, electrons may be captured by the electron scavenger benzyl viologen and not participate in the luminescence process).

[0391] Although this disclosure has been described in conjunction with exemplary embodiments which are now considered practical, it should be understood that the invention is not limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A color conversion panel, the color conversion panel comprising: A color conversion layer includes color conversion areas and optional partitions, the partitions defining each color conversion area of ​​the color conversion layer. The color conversion region includes a first region corresponding to a green pixel, and the first region includes a first composite material configured to emit green light and comprising a matrix and multiple luminescent nanostructures dispersed in the matrix. The luminescent nanostructure comprises a first semiconductor nanocrystal containing a group III-V compound and a second semiconductor nanocrystal containing a zinc chalcogenide. The group III-V compound includes indium, phosphorus, and optionally zinc, and the zinc chalcogenide includes zinc, selenium, and sulfur. The luminescent nanostructure does not include cadmium. In the luminescent nanostructures, the molar ratio of zinc to indium is greater than or equal to 12:1 and less than or equal to 25:1, and the molar ratio of selenium to indium is greater than or equal to 2:1 and less than or equal to 6.5:

1. In this embodiment, at least a portion of the surface of the luminescent nanostructure comprises a second semiconductor nanocrystal, and Among them, the full width at half maximum (FWHM) of the maximum emission peak of green light is less than or equal to 42 nanometers.

2. The color conversion panel according to claim 1, wherein, In the luminescent nanostructure, the molar ratio of zinc to indium is greater than or equal to 12:1 and less than or equal to 22:1, and the molar ratio of selenium to indium is greater than or equal to 3.5:1 and less than or equal to 6:

1.

3. The color conversion panel according to claim 2, wherein, The luminescent nanostructure exhibits a UV-Vis absorption spectrum with a positive differential coefficient at 450 nm, and The differential coefficient value is greater than or equal to 0.

001.

4. The color conversion panel according to claim 1, wherein, In the UV-Vis absorption spectrum of the luminescent nanostructure, the ratio of absorbance at the first absorption peak wavelength to absorbance at 350 nm is greater than or equal to 0.2:1, or A valley depth defined by the following equation is greater than or equal to 0.4, and the valley depth is represented by VD: 1-(Abs 谷 / Abs 第一 )=VD Among them, Abs 第一 Corresponding to the absorbance at the first absorption peak, and Abs 谷 The absorption rate corresponds to the lowest point of the valley adjacent to the first absorption peak.

5. The color conversion panel according to claim 1, wherein, The plurality of luminescent nanostructures include a sulfur to selenium molar ratio greater than or equal to 0.5:1 and less than or equal to 3.5:

1.

6. The color conversion panel according to claim 1, wherein, The plurality of luminescent nanostructures include a phosphorus to indium molar ratio greater than or equal to 0.7:1 and less than or equal to 1.5:

1.

7. The color conversion panel according to claim 1, wherein, Under incident light at wavelengths from 450 nm to 460 nm, the first complex exhibits a quantum yield loss percentage of less than 14%, where quantum yield is denoted by QY, and the QY loss percentage is defined by the following equation: QY loss (%) = [1 - (QY at 80℃ / QY at room temperature)] × 100, where, Quantum yield of QY: the first complex at 80 °C QY at room temperature: quantum yield of the first complex at room temperature.

8. The color conversion panel according to claim 1, wherein, When the first complex is irradiated with incident light at a wavelength of 458 nm, the first complex is configured to exhibit a tailing percentage of less than or equal to 15% as defined by the following equation: Trail percentage (%) = [S2 / S1] × 100 in, S1: The total area of ​​the maximum photoluminescence peak of the first complex, and S2: The area of ​​the maximum photoluminescence peak of the first complex in the wavelength region greater than or equal to 580 nm.

9. The color conversion panel according to claim 1, wherein, When the first composite is irradiated with incident light at a wavelength of 458 nm, the first composite is configured to exhibit a light conversion efficiency greater than or equal to 33% as defined by the following equation: (A / B)×100=Light conversion efficiency (%) in, A: The light dose of green light emitted from the first complex, and B: Light dose of incident light.

10. The color conversion panel according to claim 1, wherein, At the surface of the luminescent nanostructure, the molar ratio of selenium to the sum of selenium and sulfur is greater than 0 and less than or equal to 0.3:

1.

11. A group of luminescent nanostructures, in, The luminescent nanostructures include first semiconductor nanocrystals containing group III-V compounds and second semiconductor nanocrystals containing zinc chalcogenides. Among them, Group III-V compounds include indium, phosphorus, and optionally zinc, and zinc sulfides include zinc, selenium, and sulfur. The luminescent nanostructures do not include cadmium. In the luminescent nanostructures, the molar ratio of zinc to indium is greater than or equal to 12:1 and less than or equal to 25:1, and the molar ratio of selenium to indium is greater than or equal to 2:1 and less than or equal to 6.5:

1. In this embodiment, at least a portion of the surface of each of the luminescent nanostructures comprises a second semiconductor nanocrystal. Among them, the luminescent nanostructures were configured to emit green light. Among them, the luminescent nanostructure was constructed to exhibit a UV-Vis absorption spectrum with a positive differential coefficient at 450 nm, and Specifically, in the ultraviolet-visible absorption spectrum of the luminescent nanostructure, the ratio of absorbance at the first absorption peak wavelength to absorbance at a wavelength of 350 nm is greater than or equal to 0.2:

1.

12. The group according to claim 11, wherein, The luminescent nanostructures also include organic ligands bound to the surface of the luminescent nanostructures, and In the luminescent nanostructure, the molar ratio of zinc to indium is greater than or equal to 12:1 and less than or equal to 24:1, and the molar ratio of selenium to indium is greater than or equal to 3.5:1 and less than or equal to 6:

1.

13. The group according to claim 11, wherein, The differential coefficient value is greater than or equal to 0.

001.

14. The group according to claim 11, wherein, The luminescent nanostructures exhibit a quantum efficiency of ≥80%, and the maximum photoluminescence peak of the luminescent nanostructures has a full width at half maximum (FWHM) of ≥45 nm.

15. The group according to claim 11, wherein, The luminescent nanostructures have a core-shell structure comprising a core and a single shell disposed on the core. The core includes a first semiconductor nanocrystal. Each shell comprises a second semiconductor nanocrystal.

16. The group according to claim 15, wherein, The outermost layer of a single shell consists of a second semiconductor nanocrystal.

17. The group according to claim 16, wherein, The luminescent nanostructures also include organic ligands disposed on or bound to the outermost layer of a single shell.

18. The group according to claim 11, wherein, At the surface of the luminescent nanostructure, the molar ratio of selenium to the sum of selenium and sulfur is greater than 0 and less than or equal to 0.3:

1.

19. The group according to claim 11, wherein, The luminescent nanostructures comprise a sulfur to selenium molar ratio greater than or equal to 0.5:1 and less than or equal to 3.5:1, and The luminescent nanostructure includes a phosphorus to indium molar ratio greater than or equal to 0.7:1 and less than or equal to 1.5:

1.

20. An ink composition comprising a liquid carrier and the group of luminescent nanostructures according to any one of claims 11 to 19.

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