Semiconductor nanoparticles, method for manufacturing semiconductor nanoparticles, and ink composition, electroluminescent device, and display device including

Abstract

Provided are a semiconductor nanoparticle, a method for preparing the semiconductor nanoparticle, an ink composition including the semiconductor nanoparticle, an electroluminescent device, and a display device including the semiconductor nanoparticle. The semiconductor nanoparticle is configured to emit light and includes a semiconductor nanocrystal and a semiconductor nanocrystal layer including zinc and sulfur. The semiconductor nanoparticle further includes a first compound and a second compound. The first compound includes a first functional group and an aromatic hydrocarbon group or an aliphatic hydrocarbon group having a terminal double bond. The second compound includes a second functional group and an aliphatic hydrocarbon group. The first functional group and the second functional group each independently include a carboxylic acid or an anion of a carboxylic acid.

Description

[0001] This application is based on and claims priority to Korean Patent Application No. 10-2024-0097312, filed on July 23, 2024, with the Korean Intellectual Property Office, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] This disclosure relates to semiconductor nanoparticles, methods for preparing semiconductor nanoparticles, ink compositions including semiconductor nanoparticles, electroluminescent devices including semiconductor nanoparticles, and display devices including semiconductor nanoparticles. Background Technology

[0003] Semiconductor nanoparticles (e.g., quantum dots) with nanoscale dimensions can exhibit luminescent properties. For example, quantum dots comprising semiconductor nanocrystals can exhibit quantum confinement effects. Light emission from semiconductor nanoparticles can be generated when excited electrons transition from the conduction band to the valence band by, for example, photoexcitation or voltage application. By controlling the size, composition, or combinations thereof, semiconductor nanoparticles can be configured to emit light in a desired wavelength region. Semiconductor nanoparticles can be used in a variety of light-emitting devices (e.g., electroluminescent devices) and display devices. Summary of the Invention

[0004] The embodiments relate to a semiconductor nanoparticle.

[0005] The embodiments relate to an ink composition, wherein the ink comprises semiconductor nanoparticles and a solvent.

[0006] The examples relate to a method for preparing semiconductor nanoparticles.

[0007] The embodiments relate to a light-emitting device (e.g., an electroluminescent device) that emits light by itself when a voltage is applied to semiconductor nanoparticles (e.g., quantum dots).

[0008] The embodiments relate to a display device (e.g., a quantum dot (QD)-light-emitting diode (LED) display) that includes nanocrystalline particles (e.g., quantum dots) of light-emitting material as red pixels, green pixels, blue pixels, or combinations thereof.

[0009] In one embodiment, a semiconductor nanoparticle is configured to emit light (e.g., a first light) in response to an external stimulus.

[0010] The semiconductor nanoparticles include semiconductor nanocrystals containing zinc and selenium, and a semiconductor nanocrystal layer containing zinc and sulfur on the semiconductor nanocrystals.

[0011] The semiconductor nanoparticles also include a first compound and a second compound.

[0012] The first compound includes a first functional group and an aromatic hydrocarbon group or an aliphatic hydrocarbon group, wherein the aliphatic hydrocarbon group has a terminal double bond.

[0013] The second compound includes a second functional group and an aliphatic hydrocarbon group.

[0014] The first and second functional groups each independently include a carboxylic acid or an anion of a carboxylic acid (e.g., a carboxylate group).

[0015] In the gas chromatography-mass spectrometry (GC-MS) of the semiconductor nanoparticles, the first compound and the second compound exhibited a first peak and a second peak, respectively, with the retention time of the second peak being longer than that of the first peak.

[0016] Furthermore, the ratio of the area of ​​the first peak to the area of ​​the second peak is greater than or equal to about 0.1:1, or greater than or equal to about 0.15:1 and less than or equal to about 3:1, or less than or equal to about 1.4:1.

[0017] The ratio of the area of ​​the first peak to the area of ​​the second peak may be greater than or equal to about 0.2:1, or greater than or equal to about 0.25:1 and less than or equal to about 2:1, or less than or equal to about 0.15:1.

[0018] The semiconductor nanocrystal may include a first semiconductor nanocrystal.

[0019] The semiconductor nanocrystal (e.g., a first semiconductor nanocrystal) may optionally also include tellurium.

[0020] The semiconductor nanoparticles may or may not include cadmium, lead, or combinations thereof.

[0021] The semiconductor nanoparticles can be configured to emit a first light.

[0022] The first light can have a red light spectrum, a green light spectrum, or a blue light spectrum.

[0023] The semiconductor nanoparticles can be configured to emit blue light. The first light or blue light may have a peak emission wavelength greater than or equal to about 440 nanometers (nm) and less than or equal to about 480 nm.

[0024] The semiconductor nanoparticles can be configured to emit green light. The first light, or green light, may have a peak emission wavelength greater than about 480 nm and less than or equal to about 580 nm.

[0025] The semiconductor nanoparticles can be configured to emit red light. The first light or red light may have a peak emission wavelength greater than or equal to about 600 nm and less than or equal to about 680 nm.

[0026] The semiconductor nanoparticles may have a core-shell structure, wherein the core-shell structure has a core and a shell disposed on the core. The semiconductor nanoparticles or the core may include a first semiconductor nanocrystal. The core or the first semiconductor nanocrystal may include a group II-VI compound or a group III-V compound, wherein the group II-VI compounds include zinc, selenium, and optionally tellurium, and the group III-V compounds include indium and phosphorus. A semiconductor nanocrystal layer may be disposed on the first semiconductor nanocrystal.

[0027] The core or semiconductor nanocrystal (e.g., a first semiconductor nanocrystal) may include a first semiconductor nanocrystal comprising zinc selenide, zinc telluride selenide, or a combination thereof. The shell may include a semiconductor nanocrystal layer (or outer layer).

[0028] The semiconductor nanoparticles, core, or first semiconductor nanocrystal may include zinc selenide, zinc telluride selenide, indium phosphide, indium zinc sulfide, copper indium sulfide, silver indium sulfide, silver indium gallium sulfide, or combinations thereof.

[0029] The semiconductor nanoparticles may also include silver, indium, copper, or combinations thereof.

[0030] The shell may include a second zinc chalcogenide containing zinc, selenium and optional sulfur, or a second semiconductor nanocrystal (or intermediate shell) containing a second zinc chalcogenide.

[0031] In the semiconductor nanoparticles, a second semiconductor nanocrystal (or intermediate shell) may be disposed on the first semiconductor nanocrystal (or core) or between the first semiconductor nanocrystal (e.g., core) and a semiconductor nanocrystal layer (e.g., outer layer).

[0032] The semiconductor nanocrystal layer may include a third zinc chalcogenide (e.g., zinc sulfide) comprising zinc and sulfur, or a third semiconductor nanocrystal comprising the third zinc chalcogenide. The shell may include a second semiconductor nanocrystal (or an intermediate shell layer comprising the second semiconductor nanocrystal) and a third semiconductor nanocrystal (or a semiconductor nanocrystal layer or outer layer comprising the third semiconductor nanocrystal). The second zinc chalcogenide may or may not have a composition different from that of the third zinc chalcogenide. The second zinc chalcogenide may or may not include sulfur. The third zinc chalcogenide may or may not include selenium.

[0033] The molecular weight of the second compound can be greater than that of the first compound.

[0034] The first compound may have a molecular weight greater than or equal to about 150 g / mol or greater than or equal to about 160 g / mol and less than or equal to about 500 g / mol. The first compound may have a molecular weight greater than or equal to about 165 g / mol or greater than or equal to about 190 g / mol and less than or equal to about 400 g / mol.

[0035] The second compound may have a molecular weight greater than or equal to about 180 g / mol and less than or equal to about 600 g / mol. The second compound may have a molecular weight greater than or equal to about 260 g / mol and less than or equal to about 550 g / mol.

[0036] The difference in molecular weight between the first compound and the second compound can be greater than or equal to about 90 g / mol and less than or equal to about 150 g / mol.

[0037] The first compound may further include a linking group connecting the first functional group and the aromatic hydrocarbon group. The linking group may include a substituted or unsubstituted hydrocarbon group (L) having a number greater than or equal to about 3, greater than or equal to about 4, greater than or equal to about 6, or greater than or equal to about 8 and less than or equal to about 20, less than or equal to about 19, or less than or equal to about 10. The linking group may include substituted or unsubstituted hydrocarbon groups of C5 to C10. The hydrocarbon group (L) may be an aliphatic hydrocarbon group, an aromatic hydrocarbon group, or an alicyclic hydrocarbon group. In the hydrocarbon group (L), one or more methylene groups may be replaced by CO, O, COO, S, SO, SOO, NH, NHCO, or combinations thereof. The hydrocarbon group (L) may also include a double bond in its chain.

[0038] The first compound may include substituted or unsubstituted phenylhexanoic acid, substituted or unsubstituted phenylhexanoate, substituted or unsubstituted phenylvaleric acid, substituted or unsubstituted phenylvalerate, substituted or unsubstituted phenylbutyric acid, substituted or unsubstituted phenylbutyrate, substituted or unsubstituted phenylisopropionic acid, substituted or unsubstituted phenylisopropionic acid, substituted or unsubstituted phenylpropionic acid, substituted or unsubstituted phenylpropionic acid, substituted or unsubstituted 9-decenoic acid, substituted or unsubstituted 9-decenoate, substituted or unsubstituted 10-undecenoic acid, substituted or unsubstituted 10-undecenoate, substituted or unsubstituted 11-dodecenoic acid, substituted or unsubstituted 11-dodecenoate, or combinations thereof. The first compound may also include a metal ion (e.g., zinc).

[0039] The second compound may include oleic acid, oleate, myristic acid, myristic acid salt, stearic acid, stearate, lauric acid, laurate, or combinations thereof.

[0040] The peak area ratio of the second compound to the first compound may be greater than or equal to about 0.2:1, or greater than or equal to about 0.25:1 and less than or equal to about 2:1, or less than or equal to about 0.15:1.

[0041] The semiconductor nanoparticles may have an organic content of greater than or equal to about 9.5 wt%, or greater than or equal to about 10 wt% and less than or equal to about 25 wt%, or less than or equal to about 13 wt%, as determined by thermogravimetric analysis.

[0042] The semiconductor nanoparticles may have a residue content at 550°C as determined by thermogravimetric analysis, and based on the total weight of the semiconductor nanoparticles, the residue content is greater than or equal to about 86%, 86.5% or 87% and less than or equal to about 90%, 88.5% or 88.1%.

[0043] In the semiconductor nanoparticles, the chlorine content may be less than or equal to about 1 mol, based on the total elemental content.

[0044] The semiconductor nanoparticles may have a chlorine content of less than or equal to about 10%, less than or equal to about 9%, less than or equal to about 8%, less than or equal to about 7%, less than or equal to about 6%, or less than or equal to about 5% based on the total molar number of sulfur.

[0045] The semiconductor nanoparticles may have a chlorine content of less than or equal to about 10%, less than or equal to about 9%, less than or equal to about 8%, less than or equal to about 7%, less than or equal to about 6%, less than or equal to about 5%, less than or equal to about 4%, less than or equal to about 3%, or less than or equal to about 2% based on the total molar number of selenium.

[0046] The semiconductor nanoparticles may have dimensions (or average dimensions, referred to below as dimensions) greater than or equal to about 9 nm, greater than or equal to about 10 nm, greater than or equal to about 10.5 nm, greater than or equal to about 11 nm, greater than or equal to about 11.5 nm, or greater than or equal to about 12 nm and less than or equal to about 50 nm, less than or equal to about 15 nm, less than or equal to about 13 nm, less than or equal to about 12.5 nm, less than or equal to about 12 nm, or less than or equal to about 11.5 nm. The dimensions may be diameter or equivalent diameter.

[0047] The semiconductor nanoparticles may have an average particle size of less than or equal to about 45 nm, or less than or equal to about 30 nm.

[0048] The semiconductor nanoparticles can be configured to exhibit a quantum yield greater than or equal to about 80%. The semiconductor nanoparticles can be configured to exhibit a full width at half maximum (FWHM) of less than or equal to about 50 nm. The absolute quantum yield of the semiconductor nanoparticles can be greater than or equal to about 82%, or greater than or equal to about 90%. The absolute quantum yield of the semiconductor nanoparticles can be about 84% to about 100%, about 90% to about 99%, about 91% to about 98%, about 92% to about 97%, or about 93% to about 96%. The absolute quantum yield of the semiconductor nanoparticles can be greater than or equal to about 80%, or greater than or equal to about 88%. The FWHM of the semiconductor nanoparticles can be less than or equal to about 49 nm. The FWHM of the semiconductor nanoparticles can be less than or equal to about 47 nm.

[0049] In an embodiment, an ink composition comprises the semiconductor nanoparticles and a solvent, wherein the distance (Ra) between the first compound and the second compound relative to the solvent is greater than 0 and less than or equal to about 4, and Ra satisfies the following equation:

[0050] Ra²=4(δD1-δD2)²+(δP1-δP2)²+(δH1-δH2)²

[0051] Ra: Hansen solubility parameter distance

[0052] δD1: Dispersion solubility parameter of the first and second compounds excluding the COO group.

[0053] δD2: Dispersion and solubility parameter of the solvent

[0054] δP1: Polar solubility parameter of the first and second compounds excluding the COO group.

[0055] δP2: Polar solubility parameter of the solvent

[0056] δH1: Hydrogen bond parameter of the first and second compounds excluding the COO group.

[0057] δH2: Hydrogen bonding parameter of the solvent.

[0058] The Hansen solubility parameter distance (Ra) can be greater than or equal to about 1 or can be about 1.5 to about 3.

[0059] Solvents may include substituted or unsubstituted C5 to C40 alicyclic (or alicyclic) hydrocarbon solvents, substituted or unsubstituted C1 to C40 (or C5 to C30) aliphatic hydrocarbon solvents, substituted or unsubstituted C6 to C50 aromatic hydrocarbon solvents, substituted or unsubstituted C5 to C40 aliphatic ester solvents, or combinations thereof.

[0060] Solvents may include cyclohexylbenzene, hexadecane, octylbenzene, 1,3,5-triisopropylbenzene, ethyl dodecanoate, decylcyclohexane, or combinations thereof.

[0061] The solvent may have a boiling point greater than or equal to about 200°C and less than or equal to about 350°C.

[0062] In one embodiment, a method for manufacturing semiconductor nanoparticles includes: Prepare semiconductor nanocrystals (or first particles comprising semiconductor nanocrystals); and heat (e.g., to a reaction temperature) a reaction medium comprising semiconductor nanocrystals, a zinc precursor, a sulfur precursor, a first compound, and a second compound in an organic solvent to form a semiconductor nanocrystal layer comprising zinc and sulfur on the semiconductor nanocrystals (e.g., on at least a portion of the surface of the semiconductor nanocrystals or the first particles).

[0063] The steps for forming a semiconductor nanocrystal layer may include:

[0064] A first medium comprising semiconductor nanocrystals, a zinc precursor, a sulfur precursor, and a second compound is heated to a reaction temperature; and

[0065] The first compound is added to the first medium.

[0066] In an embodiment, the method may include adding a first particle, a second zinc precursor, and a sulfur precursor to an organic solvent, wherein the second zinc precursor may include a second compound.

[0067] The method may further include adding the first compound to a reaction medium or an organic solvent.

[0068] The step of adding the first compound may be carried out at a temperature greater than or equal to about 180°C and less than the reaction temperature (e.g., a second temperature), which is greater than or equal to about 190°C and less than or equal to about 300°C, greater than or equal to about 200°C and less than or equal to about 290°C, greater than or equal to about 210°C and less than or equal to about 280°C, or a combination thereof.

[0069] The addition of the first compound can be carried out at a temperature greater than or equal to approximately the boiling point of the first compound. The second temperature can be greater than or equal to approximately the boiling point of the first compound.

[0070] The amount of the first compound used may be greater than or equal to about 0.1 moles, greater than or equal to about 0.2 moles and less than or equal to about 5 moles, or less than or equal to about 1 mole per 1 mole of the second zinc precursor.

[0071] The first compound may also include a metal (e.g., zinc), and the first compound including the metal may be obtained by reaction between a metal compound (e.g., a metal acetate) and the first compound in the form of a carboxylic acid.

[0072] The details of the first and second compounds are the same as those described herein.

[0073] In one embodiment, an electroluminescent device includes an emitting layer, and the emitting layer includes semiconductor nanoparticles.

[0074] The electroluminescent device may further include a first electrode (e.g., an anode) and a second electrode (e.g., a cathode). An emitting layer may be disposed between the first electrode and the second electrode. The electroluminescent device may also include a hole transport layer, an electron transport layer, or both. The emitting layer may be disposed between the hole transport layer and the electron transport layer.

[0075] A hole transport layer may be disposed between the emitter layer and the first electrode. An electron transport layer may be disposed between the emitter layer and the second electrode.

[0076] Hole auxiliary layers (e.g., hole transport layers) may include poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)-diphenylamine) (TFB), polyarylamines, poly(N-vinylcarbazole), poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), polyaniline, polypyrrole, N,N,N',N'-tetra(4-methoxyphenyl)-benzidine (T PD), 4,4'-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl (α-NPD), m-MTDATA (4,4',4''-tris[phenyl(m-tolyl)amino]triphenylamine), 4,4',4"-tris(N-carbazolyl)-triphenylamine (TCTA), 1,1-bis[di(4-tolyl)aminophenyl]cyclohexane (TAPC), NiO, WO3, MoO3, graphene, graphene oxide, or combinations thereof.

[0077] The electron auxiliary layer (e.g., the electron transport layer) may include 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA), copper bath (BCP), tris[3-(3-pyridyl)-trimethylmethyl]borane (3TPYMB), LiF, tris(8-hydroxyquinoline)aluminum (Alq3), tris(8-hydroxyquinoline)gallium (Gaq3), tris(8-hydroxyquinoline)indium (Inq3), bis(8-hydroxyquinoline)zinc (Znq2), bis(2- (2-hydroxyphenyl)benzothiazole)zinc (Zn(BTZ)2), bis(10-hydroxybenzo[h]quinoline)beryllium (BeBq2), 8-(4-(4,6-di(naphthyl-2-yl)-1,3,5-triazin-2-yl)phenyl)quinolone (ET204), lithium 8-hydroxyquinoline (Liq), zinc oxide nanoparticles, n-type doped zinc metal oxide nanoparticles or zinc oxide nanoparticles, hafnium oxide nanoparticles, or combinations thereof.

[0078] Semiconductor nanoparticles or emitter layers may have a chlorine content of less than or equal to about 10% based on the total molar number of sulfur.

[0079] The embodiments relate to a method for manufacturing an electroluminescent device, the method comprising: obtaining an ink composition; disposing an emitting layer comprising semiconductor nanoparticles on a first electrode; and disposing a second electrode on the emitting layer.

[0080] The method may further include forming a hole transport layer on the first electrode.

[0081] The step of forming the emission layer may include: applying an ink composition onto a first electrode or a hole transport layer to obtain a film; and removing at least a portion of the solvent from the film.

[0082] The emission layer may or may not include a solvent. The emission layer may or may not include octane, cyclohexane, cyclohexylbenzene, hexadecane, octylbenzene, 1,3,5-triisopropylbenzene, ethyl dodecanoate, decylcyclohexane, or combinations thereof.

[0083] The embodiments relate to an electronic device or display device, which includes an electroluminescent device or semiconductor nanoparticles.

[0084] The display device or electronic device may include a virtual reality display device, an augmented reality display device, a wearable device, a portable terminal device, a monitor, a computer, a sensor, a television set, an electronic display panel, a camera, or an automotive electronic component.

[0085] According to embodiments, semiconductor nanoparticles with enhanced properties of controlled dispersion can be manufactured by a relatively simple method. When included in a light-emitting device, the semiconductor nanoparticles according to embodiments can help improve the properties of the device (e.g., enhance lifetime characteristics). Attached Figure Description

[0086] Figure 1 This is a schematic cross-sectional view of a quantum dot light-emitting diode (QD LED) device according to an embodiment.

[0087] Figure 2 This is a schematic cross-sectional view of a QD LED device according to another embodiment.

[0088] Figure 3 This is a schematic cross-sectional view of a QD LED device according to another embodiment.

[0089] Figure 4 This is a schematic cross-sectional view of a QD LED device according to another embodiment.

[0090] Figure 5 This is a schematic cross-sectional view of a light-emitting device (red-green-blue (RGB) pixel) according to an embodiment.

[0091] Figure 6 This is a schematic front view of the display panel according to an embodiment.

[0092] Figure 7 yes Figure 6 A schematic cross-sectional view of the display panel taken along line IV-IV.

[0093] Figure 8 The results of gas chromatography-mass spectrometry analysis are shown, which shows the intensity (count, %) of the semiconductor nanoparticles prepared in Preparation Example 3-2 against the acquisition time (i.e., retention time, RT) (min).

[0094] Figure 9A A graph showing the change in the Hansen solubility parameter distance in relation to a dispersion including semiconductor nanoparticles according to an embodiment and a predetermined solvent in Experimental Example 1, based on a change in the molar ratio of the first compound to the second compound included in the semiconductor nanoparticles.

[0095] Figure 9B A graph showing the change in the Hansen solubility parameter distance in relation to a dispersion including semiconductor nanoparticles according to an embodiment and a predetermined solvent (mixed solvent) in Experimental Example 1, based on the change in the molar ratio of the first compound to the second compound included in the semiconductor nanoparticles.

[0096] Figure 10 This is a diagram showing the results of Experiment Example 2 (fabrication and evaluation of HOD devices). Detailed Implementation

[0097] In the following, various embodiments of this disclosure will be described in detail with reference to the accompanying drawings, enabling those skilled in the art to readily implement this disclosure. This disclosure may be implemented in many different forms and is not limited to the embodiments described herein.

[0098] For clarity of this disclosure, parts unrelated to the description have been omitted, and throughout the specification, the same reference numerals have been assigned to the same or similar elements.

[0099] For better understanding and ease of description, the dimensions and thicknesses of each component shown in the accompanying drawings are arbitrarily indicated, and this disclosure is not necessarily limited to those shown. In the drawings, the thicknesses of layers, films, panels, regions, etc., are exaggerated for clarity. Furthermore, in the drawings, the thicknesses of some layers and regions are exaggerated for ease of description.

[0100] Furthermore, it will be understood that when an element (such as a layer, film, region, or substrate) is referred to as being "on" another element, it 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. Additionally, setting it "on" a reference portion means setting it above or below the reference portion, and does not necessarily mean "above" in the opposite direction of gravity.

[0101] 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, “first element,” “first component,” “first region,” “first layer,” or “first part” discussed below may be designated as a second element, second component, second region, second layer, or second part.

[0102] 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 content clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to include the plural forms containing “at least one.” Thus, a reference to an element (a) followed by a reference to the element (the) in a claim includes one element (a) and multiple elements (a).

[0103] “At least one” will not be construed as limiting “one” or “one (kind / person)”. “Or” means “and / or”. As used herein, the term “and / or” includes any and all combinations of one or more of the relevant listed items.

[0104] It will also be understood that when the terms “comprising” and / or variations thereof or “including” and / or 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.

[0105] Furthermore, relative terms such as “below” or “bottom” and “above” or “top” may be used herein 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 include different orientations of the device (apparatus) other than those depicted in the drawings. For example, if a device (apparatus) in one of the drawings is flipped, an element described as being “below” the other element will subsequently be positioned “above” the other element. The exemplary term “below” can therefore include both “below” and “above” orientations according to the specific orientation in the drawings. Similarly, if a device in one of the drawings is flipped, an element described as being “below” or “under” the other element will subsequently be positioned “above” the other element. The exemplary terms “below” or “under” can therefore include both above and below orientations.

[0106] In the specification, "section" may mean a cross-section observed from a side cut through the target portion generally perpendicularly (substantially perpendicular to the bottom surface).

[0107] Furthermore, unless otherwise stated, the singular includes the plural.

[0108] In the accompanying drawings, the thickness of layers, films, panels, areas, etc., is exaggerated for clarity. Throughout the specification, the same reference numerals designate the same elements.

[0109] As used herein, the values ​​of work function, conduction band, or lowest unoccupied molecular orbital (LUMO) (or valence band or highest unoccupied molecular orbital (HOMO)) energy levels are expressed as absolute values ​​from the vacuum level. Furthermore, deep, high, or large work function or energy level means a large absolute value when the vacuum level is set to "0 electron volts (eV)," and shallow, low, or small work function or energy level means a small absolute value when the vacuum level is set to "0 eV."

[0110] In an embodiment, the work function can refer to the minimum energy required to remove an electron from a solid metal (e.g., a metal surface) into a vacuum (e.g., a portion just outside the solid surface).

[0111] The average value can be either the mean or the median. In this example, the average value is the mean.

[0112] As used herein, the term "peak emission wavelength" is the wavelength at which a given emission spectrum of light reaches its maximum value.

[0113] As used herein, unless otherwise defined, the term "group" in "group I", "group II", "group III", etc., refers to a group of elements in the periodic table.

[0114] As used herein, “family I” may include families IA and IB, and examples may include Li, Na, K, Rb, and Cs, but are not limited thereto.

[0115] As used herein, “Group II” may include Group IIA and Group IIB, and examples of Group II metals may be Cd, Zn, Hg and Mg, but are not limited thereto.

[0116] As used herein, “Group III” may include Group IIIA and Group IIIB, and examples of Group III metals may be (but are not limited to) Al, In, Ga, and Tl.

[0117] As used herein, “Group IV” may include Group IVA and Group IVB, and examples of Group IV metals may be Si, Ge, and Sn, but are not limited thereto. As used herein, “metal” may include half-metals (such as Si).

[0118] "Group V" can include Group VA, and examples can be (but are not limited to) nitrogen, phosphorus, arsenic, antimony, and bismuth.

[0119] As used herein, “Group VI” may include Group VIA, and examples may include sulfur, selenium, tellurium, but are not limited thereto.

[0120] As used herein, unless otherwise defined, “substituted” means, for example, that at least one hydrogen atom of a compound or corresponding moiety is replaced by a substituent, which may be 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 C30 heteroaryl, 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 (-NRR', where R and R' are independently hydrogen or C1 to C6 alkyl), azide The following groups are used: α-N3, α-amidinyl (-C(=NH)NH2), hydrazine (-NHNH2), hydrazone (=N(NH2)), aldehyde (-C(=O)H), carbamoyl (-C(O)NH2), thiol (-SH), ester (-C(=O)OR, where R is a C1 to C6 alkyl or a C6 to C12 aryl), carboxyl (-COOH) or a salt thereof (-C(=O)OM, where M is an organic or inorganic cation), sulfonic acid (-SO3H) or a salt thereof (-SO3M, where M is an organic or inorganic cation), phosphate (-PO3H2) or a salt thereof (-PO3MH or -PO3M2, where M is an organic or inorganic cation) or combinations thereof.

[0121] As used herein, unless otherwise defined, a hydrocarbon group refers to a group comprising both carbon and hydrogen (e.g., an aliphatic group (such as an alkyl group, alkenyl group, or alkynyl group) or an aromatic group (such as an aryl group)). A hydrocarbon group can be a monovalent or polyvalent group formed by removing one or more hydrogen atoms from an alkane, alkene, alkynyl, or aromatic hydrocarbon. In a hydrocarbon group, at least one methylene group may be replaced by an oxide moiety, a carbonyl moiety, an ester moiety, -NH-, or a combination thereof. Unless otherwise stated to the contrary, a hydrocarbon (alkane, alkene, alkynyl, or aromatic) group may have 1 to 60, 2 to 32, 3 to 24, or 4 to 12 carbon atoms.

[0122] As used herein, unless otherwise defined, "alkyl" refers to a straight-chain or branched saturated monovalent hydrocarbon group (methyl, ethylhexyl, etc.).

[0123] As used herein, unless otherwise defined, "alkenyl" refers to a straight-chain or branched monovalent hydrocarbon group having one or more carbon-carbon double bonds.

[0124] As used herein, unless otherwise defined, "alkynyl" refers to a straight-chain or branched monovalent hydrocarbon group having one or more carbon-carbon triple bonds.

[0125] As used herein, unless otherwise defined, "aryl" means a group formed by removing hydrogen (e.g., at least one hydrogen) from an aromatic hydrocarbon (e.g., a phenyl group or a naphthyl group).

[0126] As used herein, unless otherwise defined, “heterogeneous” means one to three heteroatoms comprising N, O, S, Si, P, or combinations thereof.

[0127] As used herein, unless otherwise defined, “alkoxy” means an alkyl group (i.e., alkyl-O-) linked by oxygen (such as methoxy, ethoxy, or sec-butoxy).

[0128] As used herein, unless otherwise defined, “amino” can be -NRR, where R is independently hydrogen, C1 to C12 alkyl, C7 to C20 alkylaryl, C7 to C20 arylalkyl, or C6 to C18 aryl.

[0129] As used herein, the expression "excluding cadmium (or other harmful heavy metals)" may mean that the concentration of cadmium (or other corresponding heavy metals) is less than or equal to about 100 parts per million by weight (100 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, almost zero, or zero (e.g., undetectable by current methods). In embodiments, cadmium, its salts (or other heavy metals or their salts) may be substantially absent, or if present, in amounts or impurity levels below the detection limit of a given detection instrument (e.g., inductively coupled plasma atomic emission spectrometry).

[0130] As used herein, “about,” “basically,” or “approximately” includes the stated value and means within an acceptable range of deviation from the particular value as determined by a person skilled in the art taking into account the measurement in question and the error associated with the corresponding measurement of the particular quantity (i.e., the limitations of the measurement system).

[0131] For example, “basic” or “approximately” can mean within ±10%, ±5%, ±3%, or ±1% of the stated value, or within the standard deviation of the stated value.

[0132] As used herein, nanoparticles refer to structures having a region or characteristic dimension (e.g., at least one region or characteristic dimension) with a nanoscale size. In embodiments, the size (or average size) of the nanostructure is less than or equal to about 500 nm, 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. Such nanoparticles may have any shape.

[0133] Nanoparticles (e.g., semiconductor nanoparticles or metal oxide nanoparticles) may include, but are not limited to, nanowires, nanorods, nanotubes, supported nanostructures, nanoquadrupoles, nanotripods, nanodipods, nanodots, multipod shapes having at least two legs, etc. Nanoparticles may be, for example, substantially crystalline, substantially single-crystal, polycrystalline, (e.g., at least partially) amorphous, or combinations thereof.

[0134] For example, semiconductor nanoparticles (such as quantum dots) can exhibit quantum confinement or exciton confinement. In this specification, unless specifically defined, the term "nanoparticle or quantum dot" is not limited in its shape. Semiconductor nanoparticles (such as quantum dots) can have a size smaller than the diameter of a Bohr excitation in a bulk crystal of the same material and can exhibit quantum confinement effects. Quantum dots can emit light corresponding to their band gap energy by controlling the size of the nanocrystal that serves as the emission center.

[0135] As used herein, the term "T50" is the time (in hours, h) taken for the luminance (e.g., illuminance) of a given device to decrease to 50% of its initial luminance (100%) as the given device is driven (e.g., operated) at a predetermined initial luminance (e.g., 650 nit or 146 nit) (e.g., when the given device is driven (e.g., operated) at a predetermined initial luminance (e.g., 650 nit or 146 nit)).

[0136] As used herein, the term "T90" is the time (h) taken for the brightness (e.g., illuminance) of a given device to decrease to 90% of its initial brightness (100%) as the given device is started to be driven at a predetermined initial brightness (e.g., 650 nit or 146 nit).

[0137] As used herein, external quantum efficiency (EQE) refers to the ratio of the number of photons emitted from a light-emitting diode (LED) to the number of electrons passing through the device. EQE can be a standard for how efficiently an LED converts electrons into photons and allows them to escape. In embodiments, EQE can be determined based on the following equation:

[0138] EQE = [Injection Efficiency] × [Solid-State Quantum Yield] × [Extraction Efficiency]

[0139] Injection efficiency = the proportion of electrons injected into the active region that pass through the device;

[0140] Solid-state quantum yield = the proportion of all electron-hole complexes in the active region that emit radiation and thus produce photons; and

[0141] Extraction efficiency = the proportion of photons generated in the active region that escape from the device.

[0142] As used herein, maximum external quantum efficiency refers to the maximum value of the external quantum efficiency.

[0143] As used herein, maximum brightness refers to the maximum brightness that the device can achieve.

[0144] As used herein, quantum efficiency is a term that can be used interchangeably with quantum yield. Quantum efficiency (or quantum yield) can be measured in solution or in the solid state (in a composite). In embodiments, quantum efficiency (or quantum yield) is the ratio of emitted photons to absorbed photons via a nanostructure or group thereof. In embodiments, quantum efficiency can be measured by any method. For example, for fluorescence quantum yield or efficiency, two methods may exist: absolute methods and relative methods.

[0145] In the absolute method, quantum efficiency is obtained by detecting the fluorescence of all samples via an integrating sphere. In the relative method, the quantum efficiency of the unknown sample is calculated by comparing the fluorescence intensity of a standard dye (standard sample) with the fluorescence intensity of the unknown sample. Coumarin 153, coumarin 545, rhodamine 101 inner salt, anthracene, and rhodamine 6G can be used as standard dyes according to their photoluminescence (PL) wavelengths, but this disclosure is not limited thereto.

[0146] Unless otherwise stated, the range of values ​​stated herein is inclusive.

[0147] Unless otherwise stated, the numerical range described herein includes any real number within the endpoints of the stated range, and includes the endpoints of the stated range. In this specification, numerical endpoints, or upper or lower limits (e.g., described as “greater than or equal to,” “at least,” or “less than or equal to,” or described as “from” or “to”) may be used to form a numerical range for a given characteristic. In other words, the upper and lower endpoints described for various numerical values ​​may be independently combined to provide a range.

[0148] In embodiments, a “dispersion” can be a dispersion in which the dispersed phase is a solid and the continuous medium includes a liquid. In embodiments, a “dispersion” can refer to a colloidal dispersion 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, greater than or equal to about 4 nm, greater than or equal to about 5 nm, or greater than or equal to about 10 nm) and a few micrometers (μm) or smaller (e.g., less than or equal to about 2 μm, or 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).

[0149] The band gap energy of semiconductor nanoparticles can be varied depending on the size, structure, and composition of the nanocrystals. For example, as the size of quantum dots increases, they can exhibit narrower band gap energies and increased emission wavelengths. Semiconductor nanocrystals have attracted attention as luminescent materials in various fields, including display devices, energy devices, and bioluminescent devices.

[0150] Semiconductor nanoparticles with practically applicable levels of electroluminescent properties may include harmful heavy metals (such as cadmium (Cd), lead, mercury, or combinations thereof). It is desirable to provide semiconductor nanoparticles that emit light of desired wavelengths while being substantially free of harmful heavy metals. Furthermore, from an environmental perspective, it is desirable to provide light-emitting devices or display devices having a light-emitting layer based on semiconductor nanoparticles that do not contain cadmium (a harmful heavy metal).

[0151] The semiconductor nanoparticles according to the embodiments are environmentally friendly, can emit blue light with a desired wavelength with improved luminous efficiency, and exhibit improved stability in external environments. The electroluminescent device according to the embodiments is a self-emitting light-emitting device comprising semiconductor nanoparticles and is configured to emit desired light by voltage application with or without a separate light source. From an environmental perspective, the light-emitting device and display device of the embodiments are desirable.

[0152] Current research explores the formation of an emitting layer in an electroluminescent device using inkjet printing, wherein the emitting layer includes semiconductor nanoparticles. Ink compositions including semiconductor nanoparticles used in inkjet printing may include a predetermined solvent and semiconductor nanoparticles. There is a technological need for ink compositions that can be ejected from the printhead of an inkjet printing apparatus and deposited onto a desired substrate (e.g., an electrode or charge transport layer) to form an emitting layer of desired quality. The semiconductor nanoparticles and ink compositions including the semiconductor nanoparticles of the embodiments can be applied to electroluminescent devices or to the manufacture of electroluminescent devices.

[0153] In an embodiment, the semiconductor nanoparticles are configured to emit a first light. The semiconductor nanoparticles include a semiconductor nanocrystal layer comprising zinc and sulfur, and may further include (e.g., incorporated into the semiconductor nanocrystal layer) a first compound and a second compound. The first compound includes: a first functional group; and a substituted or unsubstituted aromatic hydrocarbon group or a substituted or unsubstituted aliphatic hydrocarbon group having a terminal double bond, and the second compound includes: a second functional group; and a substituted or unsubstituted aliphatic hydrocarbon group. The first functional group may include a carboxylic acid or its anion (e.g., a carboxyl group). The second functional group may include a carboxylic acid or its anion (e.g., a carboxyl group).

[0154] The first and second compounds (e.g., the first and second functional groups) can be incorporated into semiconductor nanoparticles or semiconductor nanocrystal layers. In gas chromatography-mass spectrometry (GC-MS) of the semiconductor nanoparticles (e.g., relative to the semiconductor nanoparticles), the first and second compounds exhibit a first peak and a second peak, respectively, and the retention time of the second peak is greater than that of the first peak. The ratio of the area of ​​the first peak to the area of ​​the second peak is greater than or equal to about 0.1:1 and less than or equal to about 3:1.

[0155] The first light can be blue, green, or red.

[0156] In an embodiment, the electroluminescent device includes an emitting layer (light-emitting layer) 3 comprising semiconductor nanoparticles. The electroluminescent device may also include a first electrode 1 and a second electrode 5 spaced apart (e.g., facing each other). The electroluminescent device may also include a hole-assisted layer 2, an electron-assisted layer 4, or both. The emitting layer 3 may be disposed between the first electrode 1 and the second electrode 5. The emitting layer 3 may be disposed between the hole-assisted layer 2 and the electron-assisted layer 4. The hole-assisted layer 2 may be disposed between the first electrode (e.g., anode) 1 and the emitting layer 3. The electron-assisted layer 4 may be disposed between the second electrode (e.g., cathode) 5 and the emitting layer 3 (see [link to documentation]). Figure 1 Semiconductor nanoparticles or emitter layers may or may not contain cadmium, mercury, or lead.

[0157] The first electrode 1 may include an anode, and the second electrode 5 may include a cathode. Optionally, the first electrode 1 may include a cathode, and the second electrode 5 may include an anode. The electroluminescent device may also include a hole-assisted layer 2 between the emitting layer 3 and the first electrode 1. The electroluminescent device may also include an electron-assisted layer 4 between the emitting layer 3 and the second electrode 5.

[0158] In embodiments of the electroluminescent device, the first electrode 10 or the second electrode 50 may be disposed on the (transparent) substrate 100. The transparent substrate 100 may be a light-extracting surface (see...). Figure 2 and Figure 3 ).

[0159] Reference Figure 2 and Figure 3 The light-emitting layer 30 may be disposed between a first electrode (e.g., an anode) 10 and a second electrode (e.g., a cathode) 50. The second electrode or cathode 50 may include an electron injection conductor. The first electrode or anode 10 may include a hole injection conductor. The work function of the electron / hole injection conductors included in the second electrode 50 and the first electrode 10 may be appropriately adjusted and is not particularly limited. For example, the second electrode 50 may have a small work function and the first electrode 10 may have a relatively large work function, or vice versa.

[0160] Electron / hole injection conductors may include, but are not limited to, metallic materials (e.g., metals, metal compounds, alloys, or combinations thereof) such as aluminum, magnesium, tungsten, nickel, cobalt, platinum, palladium, calcium, LiF, etc.), metal oxides (e.g., indium gallium oxide or indium tin oxide (ITO)) or (e.g., conductive polymers with relatively high work function) such as polyethylene dioxythiophene.

[0161] At least one of the first electrode and the second electrode may be a light-transmitting electrode or a transparent electrode. In an embodiment, both the first electrode and the second electrode may be light-transmitting electrodes. One or more electrodes may be patterned. The first electrode and / or the second electrode may be disposed on a substrate 100 (e.g., an insulating substrate). The substrate 100 may be optically transparent (e.g., it 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%, greater than or equal to about 85%, or greater than or equal to about 90%, and for example less than or equal to about 99%, or less than or equal to about 95%). The substrate may also include regions for blue pixels, regions for red pixels, regions for green pixels, or combinations thereof. Thin-film transistors may be disposed in each region of the substrate, and one of the source electrode and drain electrode of the thin-film transistor may be electrically connected to the first electrode or the second electrode.

[0162] The transparent electrode can be disposed on a transparent substrate (e.g., an insulating one). The substrate can be rigid or flexible. The substrate can be plastic, glass, or metal.

[0163] The light-transmitting electrode may have a transmittance of more than or equal to about 50%, more than or equal to about 60%, more than or equal to about 70%, more than or equal to about 80%, or more than or equal to about 90% (e.g., in the range of about 80% to about 100%, about 85% to about 95%, or combinations thereof).

[0164] The transparent electrode may include, for example, a transparent conductor (such as indium tin oxide (ITO) or indium zinc oxide (IZO), gallium indium tin oxide, zinc indium tin oxide, titanium nitride, polyaniline, LiF / Mg:Ag, etc.) or a single or multilayer metal thin film, but is not limited thereto. The first electrode, the second electrode, or combinations thereof may include silver, aluminum (Al), lithium aluminum (Li:Al) alloys, magnesium-silver alloys (Mg:Ag), lithium fluoride-aluminum (LiF:Al), etc. In the alloy electrode, the ratio between the materials may be suitably controlled, for example, within the range of about 1:0.1 to about 1:10, about 1:0.2 to about 1:5, about 1:0.3 to about 1:3, or combinations thereof.

[0165] In an embodiment, the first electrode or the second electrode may be a multilayer electrode. In an embodiment, the first electrode (or anode) may be a multilayer electrode comprising two or more layers, three or more layers and ten or fewer layers, or five or fewer layers of electrode material. In an embodiment, the second electrode (or cathode) may be a multilayer electrode comprising two or more layers, three or more layers and ten or fewer layers, or five or fewer layers of electrode material.

[0166] Multilayer electrodes may include, for example, light-transmitting conductive materials (or transparent conductive materials) (such as indium tin oxide), opaque conductive materials (or reflective electrode materials) (such as aluminum), or combinations thereof. In embodiments, the electrode (e.g., an anode or a cathode) may have a structure in which layers of opaque conductive material (or reflective electrode material) are disposed between layers of transparent conductive material (e.g., transparent conductive material layers). In embodiments, the electrode (anode or cathode) may have a structure in which layers of light-transmitting conductive material (e.g., light-transmitting conductive material layers) are disposed between layers of opaque conductive material (or reflective electrode material).

[0167] When a voltage is applied between the first electrode and the second electrode, the light-emitting layer can emit light upwards and downwards through the electric field, and the light traveling to the reflective electrode can be reflected and emitted in the opposite direction.

[0168] In one embodiment, light may be emitted toward the cathode. In another embodiment, light may be emitted toward the anode.

[0169] There are no particular limitations on the thickness of the electrodes (first electrode and / or second electrode), and they can be appropriately selected with regard to device efficiency. For example, the thickness of the electrodes can be greater than or equal to about 5 nm (e.g., greater than or equal to about 10 nm, greater than or equal to about 20 nm, greater than or equal to about 30 nm, greater than or equal to about 40 nm, or greater than or equal to about 50 nm). For example, the thickness of the electrode may be less than or equal to about 100 micrometers (μm) (e.g., less than or equal to about 90 μm, less than or equal to about 80 μm, less than or equal to about 70 μm, less than or equal to about 60 μm, less than or equal to about 50 μm, less than or equal to about 40 μm, less than or equal to about 30 μm, less than or equal to about 20 μm, less than or equal to about 10 μm, less than or equal to about 1 μm, less than or equal to about 900 nm, less than or equal to about 500 nm, less than or equal to about 100 nm, less than or equal to about 90 nm, less than or equal to about 80 nm, less than or equal to about 70 nm, or less than or equal to about 60 nm).

[0170] There are no particular limitations on the method of forming the electrode, and it can be appropriately selected depending on the material. In embodiments, the electrode can be formed by (but is not limited to) deposition, coating, or a combination thereof.

[0171] A light-emitting layer (emitting layer) 3 or 30 is disposed between the first electrode 1 and the second electrode 5 (e.g., the anode 10 and the cathode 50). The light-emitting layer includes one or more semiconductor nanoparticles (e.g., blue light-emitting nanoparticles, red light-emitting nanoparticles, or green light-emitting nanoparticles). The light-emitting layer may include one or more (e.g., two or more, or three or more and ten or fewer) monolayers of multiple semiconductor nanoparticles.

[0172] The light-emitting layers may be patterned. In embodiments, the patterned light-emitting layers may include a blue light-emitting layer (or blue emitting layer) (e.g., disposed within a blue pixel in a display device described later), a red light-emitting layer (or red emitting layer) (e.g., disposed within a red pixel in a display device described later), a green light-emitting layer (or green emitting layer) (e.g., disposed within a green pixel in a display device described later), or a combination thereof. Each of the light-emitting layers may be separated from an adjacent light-emitting layer (e.g., optically) by a partition wall. In embodiments, the partition wall or dam (such as a black matrix or pixel defining layer (PDL)) may be disposed between (one or more) red emitting layers, (one or more) green emitting layers, and (one or more) blue emitting layers (see reference 1). Figure 4 and Figure 5 In this embodiment, the red, green, and blue emitting layers are each substantially optically isolated.

[0173] In some embodiments, the light-emitting layer or semiconductor nanoparticles may not include cadmium. In some embodiments, the light-emitting layer or semiconductor nanoparticles may not include mercury, lead, or combinations thereof. In some embodiments, the semiconductor nanoparticles may not include, or may include, copper, manganese, or combinations thereof.

[0174] In an embodiment, the semiconductor nanoparticles are configured to emit first light, and the semiconductor nanoparticles include a semiconductor nanocrystal layer comprising zinc and sulfur. In an embodiment, the semiconductor nanoparticles may include zinc, selenium, and sulfur. The semiconductor nanoparticles may have a core-shell structure. In an embodiment, the semiconductor nanoparticles or core-shell structure may include: a first semiconductor nanocrystal (or a core comprising the first semiconductor nanocrystal); and a semiconductor nanocrystal layer disposed on the first semiconductor nanocrystal (or a shell comprising the semiconductor nanocrystal layer).

[0175] In the embodiments, the semiconductor nanoparticles or first semiconductor nanocrystals may or may not include group II-VI compounds, group III-V compounds, group III-VI compounds, group I-III compounds, group I-III-VI compounds, metal halide perovskite compounds, metal chalcogenide perovskite compounds, or combinations thereof. The semiconductor nanoparticles may or may not include zinc selenide, zinc telluride selenide, indium phosphide, indium zinc phosphide, silver indium sulfide, copper indium sulfide, silver gallium sulfide, silver indium gallium sulfide, or combinations thereof.

[0176] Environmentally friendly, Cd-free semiconductor nanoparticles (or quantum dots) may have a structure comprising a core having a predetermined composition (e.g., ZnSe, ZnTeSe, InP, AgInGaS, etc.) and a ZnS shell disposed on the core (e.g., a core / ZnSe / ZnS core / shell / shell structure). In such core-shell quantum dots, the luminescent center is the core, and a ZnS shell having a band gap wider than that of the core may be disposed on the core. In such shell-forming reactions, a portion of a compound used as a precursor or a compound added to the reaction system, or a portion thereof, may be included in or incorporated into the semiconductor nanoparticles (e.g., incorporated into a semiconductor nanocrystal layer). For example, fatty acid compounds (such as oleic acid or stearic acid) are used in the preparation of a precursor (e.g., a zinc precursor), and the resulting semiconductor nanoparticles may also include a portion derived from the fatty acid compound (such as oleic acid).

[0177] In the fabrication of quantum dot-based self-emitting display devices, the formation of an emitting layer (light-emitting layer) using inkjet printing technology has been continuously studied. The ink composition used for inkjet printing may also include a predetermined solvent along with semiconductor nanoparticles. The ink composition can be deposited on electrodes or charge transport layers to form the emitting layer. However, the inventors have discovered that ink compositions comprising semiconductor nanoparticles manufactured by conventional techniques and a predetermined solvent can be difficult to form an emitting layer with the desired quality level on electrodes or portions of some charge transport layers.

[0178] In this regard, attempts have been made to control the composition of organic compounds included in semiconductor nanoparticles by performing ligand exchange (LE) on the manufactured semiconductor nanoparticles. However, the inventors have found that ligand exchange can cause degradation of the luminescent properties of semiconductor nanoparticles (e.g., including organic compounds derived from fatty acids), and can ultimately have a negative impact on the properties of the emission layer. Furthermore, the inventors have confirmed that due to particle aggregation or agglomeration, it is difficult to achieve the desired emission film quality on some charge transport layers using ink compositions including ligand-exchanged semiconductor nanoparticles and a predetermined organic solvent, which can hinder improvements in the properties (e.g., electroluminescent properties and / or lifetime) of the manufactured electroluminescent devices. The inventors have also found that in the case of ligand-exchanged semiconductor nanoparticles, the luminescent efficiency can be significantly lower than the original luminescent efficiency before ligand exchange (e.g., from about 10% to about 30%).

[0179] The semiconductor nanoparticles of the embodiments are intended to address problems of conventional techniques. According to the embodiments, the semiconductor nanoparticles can achieve enhanced optical properties using desired organic compositions without the need for ligand exchange processes. The semiconductor nanoparticles of the embodiments may include both a portion having double bonds or an aromatic portion having a relatively short chain length, and a fatty acid-derived compound having a relatively long chain length, thereby exhibiting the desired dispersibility in a wide range of solvents and providing process flexibility in the preparation of ink compositions. Furthermore, when applied to a charge transport layer (e.g., a hole-assisted layer), ink compositions including the semiconductor nanoparticles of the embodiments can form an emission layer with improved quality (e.g., significantly reduced defects), and the fabricated light-emitting device can exhibit enhanced electroluminescent properties and increased lifetime. In the embodiments, the semiconductor nanoparticles or emission layer also include a first compound and a second compound. The first and second compounds may be, for example, organic substances (e.g., ligands) that the semiconductor nanoparticles possess due to their fabrication (e.g., bound to a semiconductor nanocrystal layer).

[0180] The first compound may include: a first functional group (X1); and a substituted or unsubstituted aromatic hydrocarbon group (Ar) (e.g., C6 to C30 or C6 to C18) or a substituted or unsubstituted aliphatic hydrocarbon group (AL1) having a double bond at its terminal. The second compound may include: a second functional group (X2); and an aliphatic hydrocarbon group having C8 to C40 (AL2). The first and second functional groups may each independently include a carboxylic acid or its anion (e.g., a carboxylate group). The first compound may have a smaller molecular weight than the second compound. The first compound may have a larger molecular weight than the second compound.

[0181] Aliphatic hydrocarbon groups with double bonds at their ends may also include one or more double bonds in the middle portion of the chain. Aliphatic hydrocarbon groups with double bonds at their ends may have a number of carbons greater than or equal to about 5, greater than or equal to about 6, greater than or equal to about 7, greater than or equal to about 8, greater than or equal to about 9, greater than or equal to about 10, greater than or equal to about 11, greater than or equal to about 12, greater than or equal to about 13, greater than or equal to about 14, greater than or equal to about 15, or greater than or equal to about 16. Aliphatic hydrocarbon groups with double bonds at their ends may have a number of carbons less than or equal to about 30, less than or equal to about 27, less than or equal to about 25, less than or equal to about 20, less than or equal to about 18, less than or equal to about 16, less than or equal to about 14, or less than or equal to about 12.

[0182] In the first compound, a linker (L) may be present, connecting the first functional group and the aromatic hydrocarbon group. The linker may include a substituted or unsubstituted hydrocarbon group having a carbon number greater than or equal to about 2, greater than or equal to about 3, greater than or equal to about 4, greater than or equal to about 5, or greater than or equal to about 6 and less than or equal to about 20, less than or equal to about 15, less than or equal to about 10, or less than or equal to about 8 (aliphatic, alicyclic, or aromatic). The linker may include substituted or unsubstituted C5 to C10 hydrocarbon groups.

[0183] In the aliphatic hydrocarbon group having a double bond at its end in the first compound, or in the linking group (L), one or more methylene groups may be replaced by O, CO, COO, S, SO, SOO, NH, NHCO, or combinations thereof. The aliphatic hydrocarbon group having a double bond at its end in the first compound or the linking group (L) may also include one or more (e.g., two, three, four, or five) double bonds in the chain.

[0184] The first compound may also include a metal (e.g., zinc). A first compound including a metal can be obtained by reacting a metal compound (e.g., a metal acetate) with a first compound in the form of a carboxylic acid. The metal compound may include zinc acetate.

[0185] The first compound may include a compound or part represented by chemical formula 1-1, a compound or part represented by chemical formula 1-2, or a combination thereof:

[0186] Chemical Formula 1-1

[0187] X1-L1-Ar

[0188] Chemical formula 1-2

[0189] X1-AL1

[0190] And in the above formula,

[0191] X1 is COOH or COO ,in, This indicates the anionic portion or the site where it binds to a semiconductor nanocrystal or a metal ion;

[0192] L1 is a substituted or unsubstituted hydrocarbon group having C1 to C20, C2 to C18, C3 to C16, C4 to C14, C5 to C12, C6 to C10 or C8 to C9 (e.g., an aliphatic hydrocarbon group (such as an alkylene or alkenylene group) or an alicyclic hydrocarbon group).

[0193] Ar is a substituted or unsubstituted C6 to C20 aromatic hydrocarbon group (e.g., aryl (such as phenyl or benzyl) or naphthyl);

[0194] AL1 is a group represented by the following chemical formula 1-2-1:

[0195] Chemical formula 1-2-1

[0196] -L2-CR=CR2

[0197] Furthermore, in the above formula, L2 is a substituted or unsubstituted aliphatic hydrocarbon group having C1 to C20, C2 to C18, C3 to C16, C4 to C14, C5 to C12, C6 to C10, or C8 to C9.

[0198] R is independently hydrogen, substituted or unsubstituted C1 to C5 alkyl groups, or combinations thereof, and

[0199] This indicates the site connected to X1.

[0200] In L1 and L2, one or more methylene groups may be replaced by O, CO, COO, S, SO, SOO, NH, NHCO, or combinations thereof. In embodiments, L1 and L2 may also include one or more (e.g., two or five) double bonds, aryl moieties, or combinations thereof in the chain.

[0201] In the embodiments, the first compound further includes a metal, and the first compound may be represented by the following formula:

[0202] Chemical formula 1-1-1

[0203]

[0204] Chemical formula 1-2-2

[0205]

[0206] Furthermore, in the above formula, M can be a metal (such as a monovalent, divalent, or trivalent metal) and may include, for example, zinc, and n may correspond to the valence of the metal. X1, L1, Ar, and AL1 are as defined herein.

[0207] The first compound may include substituted or unsubstituted phenylhexanoic acid, substituted or unsubstituted phenylhexanoate, substituted or unsubstituted phenylvaleric acid, substituted or unsubstituted phenylvaleric acid, substituted or unsubstituted phenylbutyric acid, substituted or unsubstituted phenylbutyrate, substituted or unsubstituted phenylisopropionic acid, substituted or unsubstituted phenylisopropionic acid, substituted or unsubstituted phenylpropionic acid, substituted or unsubstituted phenylpropionic acid, substituted or unsubstituted phenylpropionic acid, substituted or unsubstituted 9-decenoic acid, substituted or unsubstituted 9-decenoate, substituted or unsubstituted 10-undecenoic acid, substituted or unsubstituted 10-undecenoate, substituted or unsubstituted 11-dodecenoic acid, substituted or unsubstituted 11-dodecenoate, or combinations thereof.

[0208] The second compound may include: a second functional group (X2); and a substituted or unsubstituted aliphatic hydrocarbon group having C6 to C50, C8 to C40, C9 to C38, C10 to C36, C11 to C34, C12 to C32, C14 to C30, C15 to C28, C16 to C26, C17 to C24, or C18 to C22 (AL2). The second functional group of the second compound may be a carboxylic acid or its anion (carboxylate group). The aliphatic hydrocarbon group of the second compound may be alkyl, alkenyl, or alkynyl. The aliphatic hydrocarbon group of the second compound may also include one or more double bonds in the middle of the chain. In the aliphatic hydrocarbon group of the second compound, one or more methylene groups may be replaced by O, CO, COO, S, SO, SOO, NH, NHCO, or combinations thereof.

[0209] The second compound can be represented by the following chemical formula 2:

[0210] Chemical formula 2

[0211] X2-AL2

[0212] In the above formula, X2 is COOH or COO ,in, This indicates anion sites or sites that bind to semiconductor nanocrystals;

[0213] AL2 is a group represented by the following chemical formula 2-1:

[0214] Chemical formula 2-1

[0215] -L3-CR3

[0216] Furthermore, in the above formula, L3 is a substituted or unsubstituted aliphatic hydrocarbon group having C6 to C50, C8 to C40, C10 to C36, C12 to C32, C14 to C28, C16 to C26, or C18 to C24. The site is indicated by the connection to X2; and each R is independently hydrogen, substituted or unsubstituted C1 to C5 alkyl, or a combination thereof.

[0217] In L3, one or more methylene groups may be replaced by O, CO, COO, S, SO, SOO, NH, NHCO, or combinations thereof. L3 may also include one or more (e.g., two or five) double bonds in the chain.

[0218] The second compound may include oleic acid, oleate, myristic acid, myristic acid salt, stearic acid, stearate, lauric acid, laurate, or combinations thereof.

[0219] In the embodiments, the semiconductor nanoparticles comprise a first compound and a second compound. Therefore, when the semiconductor nanoparticles are analyzed by gas chromatography-mass spectrometry (GC-MS), the gas chromatogram shows a first peak for the first compound (i.e., attributed to the first compound) and a second peak for the second compound (i.e., attributed to the second compound). In the gas chromatography, the retention time of the second peak is greater than that of the first peak, and the area ratio of the first peak to the second peak is greater than or equal to about 0.1:1 and less than or equal to about 3:1.

[0220] The retention time of the second peak may be longer than that of the first peak. The ratio of the retention time of the first peak (i.e., the elution time of the first compound) to the retention time of the second peak (i.e., the elution time of the second compound) may be greater than or equal to about 0.1:1, greater than or equal to about 0.2:1, greater than or equal to about 0.3:1, greater than or equal to about 0.4:1, greater than or equal to about 0.5:1, greater than or equal to about 0.6:1, greater than or equal to about 0.7:1, greater than or equal to about 0.75:1, or greater than or equal to about 0.8:1. The ratio of the retention time of the first peak to the retention time of the second peak may be less than 1:1, less than or equal to about 0.9:1, less than or equal to about 0.8:1, less than or equal to about 0.7:1, less than or equal to about 0.6:1, or less than or equal to about 0.5:1.

[0221] The difference in retention time between the second peak and the first peak may be greater than or equal to approximately 2 minutes, greater than or equal to approximately 3 minutes, greater than or equal to approximately 4 minutes, greater than or equal to approximately 5 minutes, greater than or equal to approximately 6 minutes, greater than or equal to approximately 8 minutes, greater than or equal to approximately 9 minutes, or greater than or equal to approximately 10 minutes. The difference in retention time between the second peak and the first peak may be less than or equal to approximately 15 minutes, less than or equal to approximately 13 minutes, less than or equal to approximately 12 minutes, less than or equal to approximately 11 minutes, less than or equal to approximately 10 minutes, less than or equal to approximately 9 minutes, less than or equal to approximately 7 minutes, or less than or equal to approximately 2 minutes.

[0222] The area ratio of the first peak to the second peak can be greater than or equal to approximately 0.1:1, greater than or equal to approximately 0.13:1, greater than or equal to approximately 0.15:1, greater than or equal to approximately 0.17:1, greater than or equal to approximately 0.19:1, greater than or equal to approximately 0.2:1, greater than or equal to approximately 0.23:1, greater than or equal to approximately 0.25:1, greater than or equal to approximately 0.27:1, greater than or equal to approximately 0.3:1, greater than or equal to approximately 0.32:1, greater than or equal to approximately 0.33:1, greater than or equal to approximately 0.35:1, greater than or equal to approximately 0.4:1, greater than or equal to approximately 0.42:1, greater than or equal to approximately 0.44:1, greater than or equal to approximately 0.46:1, greater than or equal to approximately 0.48:1, greater than or equal to approximately 0.5:1, greater than or equal to approximately 0.55:1, greater than or equal to approximately 0.6:1, or larger. The ratio is greater than or equal to approximately 0.65:1, 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 0.9:1, greater than or equal to approximately 0.95:1, greater than or equal to approximately 1:1, greater than or equal to approximately 1.1:1, greater than or equal to approximately 1.2:1, greater than or equal to approximately 1.3:1, greater than or equal to approximately 1.4:1, greater than or equal to approximately 1.5:1, greater than or equal to approximately 1.6:1, greater than or equal to approximately 1.7:1, greater than or equal to approximately 1.8:1, greater than or equal to approximately 1.9:1, greater than or equal to approximately 2.1:1, greater than or equal to approximately 2.3:1, greater than or equal to approximately 2.5:1, greater than or equal to approximately 2.7:1, greater than or equal to approximately 2.9:1, or greater than or equal to approximately 2.95:1. The area ratio of the first peak to the second peak can be less than or equal to approximately 3:1, less than or equal to approximately 2.8:1, less than or equal to approximately 2.6:1, less than or equal to approximately 2.4:1, less than or equal to approximately 2.2:1, less than or equal to approximately 2:1, less than or equal to approximately 1.85:1, less than or equal to approximately 1.75:1, less than or equal to approximately 1.65:1, less than or equal to approximately 1.55:1, less than or equal to approximately 1.45:1, less than or equal to approximately 1.35:1, less than or equal to approximately 1.25:1, less than or equal to approximately 1.15:1, less than or equal to approximately 1:1, or smaller. The ratios are approximately 0.97:1, 0.93:1, 0.91:1, 0.89:1, 0.84:1, 0.79:1, 0.74:1, 0.72:1, 0.71:1, 0.68:1, 0.64:1, 0.59:1, 0.57:1, 0.53:1, or 0.49:1.

[0223] Gas chromatography (GC) is an analytical technique used to separate, identify, and quantify individual chemical components in complex mixtures. In GC, a gas carrying the sample passes through a GC instrument. In embodiments, the carrier gas or mobile phase is not particularly limited and can be high-purity helium, hydrogen, or nitrogen. In embodiments, the gas chromatographic analytical apparatus may include, but is not limited to, an injector (e.g., a split / splitless (SSL) injector), a column (e.g., a wall-coated open-tube (WCOT) capillary column comprising a thin layer of dimethylpolysiloxane stationary phase), and a detector (e.g., a flame ionization detector (FID) or mass spectrometry (MS)). In embodiments, the GC column may be a capillary column and may be a fused silica capillary comprising a polymer outer coating. In chromatograms obtained by GC, the x-axis represents retention time (typically in minutes), and the y-axis represents detector response. In embodiments, the GC apparatus may be a py-GC / MS. In a GC, the temperature of the pyrolyzer can be greater than or equal to about 100°C, greater than or equal to about 150°C, greater than or equal to about 200°C, or greater than or equal to about 250°C, and can be from about 400°C to about 600°C or from about 450°C to about 550°C. GC equipment may include a capillary column. The capillary column may include a stationary phase of a polysiloxane (e.g., dimethylpolysiloxane, 5% to 65% diphenyldimethylpolysiloxane, polyethylene glycol, etc.), and the polarity may be suitably selected.

[0224] The flow rate of the mobile phase (gas) can be appropriately selected and can be in the range of 0.5 mL / min to 10 mL / min, or 1 mL / min to 5 mL / min, or 1.5 mL / min to 3 mL / min. The inlet temperature of the GC apparatus can be appropriately selected and can be in the range of 100°C to 400°C, 150°C to 300°C, or 200°C to 250°C. The GC oven temperature can be appropriately controlled. The analyzer can be a quadrupole type (range: mass-to-charge ratio (m / z) of 10 to 550).

[0225] For gas chromatography analysis, semiconductor nanoparticles of a predetermined weight (e.g., 0.1 mg) can be treated with approximately 1 μL of an alkaline solution (e.g., trimethylammonium hydroxide), and the resulting solution can be analyzed. For mass spectrometry, solvent delay can be used to remove data from the extraction solvent.

[0226] In semiconductor nanoparticles, the molar ratio of the first compound to the second compound may be greater than or equal to about 0.1:1, greater than or equal to about 0.15:1, greater than or equal to about 0.19:1, greater than or equal to about 0.2:1, greater than or equal to about 0.25:1, greater than or equal to about 0.3:1, greater than or equal to about 0.31:1, greater than or equal to about 0.32:1, greater than or equal to about 0.35:1, greater than or equal to about 0.4:1, greater than or equal to about 0.45:1, greater than or equal to about 0.5:1, greater than or equal to about 0.55:1, greater than or equal to about 0.6:1, or greater than or equal to about 0.65:1.

[0227] In semiconductor nanoparticles, the molar ratio of the first compound to the second compound can be less than or equal to approximately 3:1, less than or equal to approximately 2.7:1, less than or equal to approximately 2.5:1, less than or equal to approximately 2.3:1, less than or equal to approximately 2.2:1, less than or equal to approximately 2.1:1, less than or equal to approximately 2:1, less than or equal to approximately 1.8:1, less than or equal to approximately 1.7:1, less than or equal to approximately 1.6:1, less than or equal to approximately 1.5:1, or less than or equal to approximately 0.95:1. Less than or equal to approximately 0.9:1, less than or equal to approximately 0.85:1, less than or equal to approximately 0.8:1, less than or equal to approximately 0.75:1, less than or equal to approximately 0.7:1, less than or equal to approximately 0.65:1, less than or equal to approximately 0.6:1, less than or equal to approximately 0.55:1, less than or equal to approximately 0.5:1, less than or equal to approximately 0.45:1, less than or equal to approximately 0.4:1, less than or equal to approximately 0.35:1, or less than or equal to approximately 0.33:1.

[0228] In the embodiments, semiconductor nanoparticles can exhibit improved dispersibility in various types of solvents and can be included in ink compositions, for example, for inkjet printing. To fabricate the emitting layer of an electroluminescent device using an inkjet printing process, suitable ink compositions need to be developed. Organic solvents for inkjet printing include predetermined solvents with relatively high boiling points. The ink solvent can have a high boiling point, and for ejection stability at the nozzle and pixel consistency (uniformity), the ink solvent can be in the form of a mixture comprising straight-chain aliphatic hydrocarbons, cyclic aliphatic hydrocarbons, and aromatic hydrocarbons, rather than a single solvent.

[0229] The inventors have discovered that semiconductor nanoparticles prepared according to conventional techniques (e.g., semiconductor nanoparticles comprising compounds derived from oleic acid) can exhibit desired dispersibility or compatibility in some organic solvents, but may not provide the required level of dispersibility or compatibility in organic solvents used for inkjet printing. For example, if the semiconductor nanoparticles include ligands with short chain lengths, the dispersibility of the semiconductor nanoparticles in ink solvents can be reduced, which can be a technical obstacle to forming an emitter layer via inkjet printing.

[0230] Surprisingly, the inventors have discovered that the semiconductor nanoparticles of the embodiments exhibit desired levels of dispersibility in high-boiling-point organic solvents (e.g., mixtures of high-boiling-point organic solvents) suitable for inkjet printing processes due to the features described herein (e.g., the presence of the first and second compounds). After being formed as an emitter layer, the semiconductor nanoparticles can provide improved charge transport properties (e.g., hole transport properties), initial drive stability, and extended lifetime characteristics in the device. The semiconductor nanoparticles of the embodiments can exhibit enhanced hole transport properties while including the amount of organic material specified herein.

[0231] Therefore, in the embodiments, the ink composition includes semiconductor nanoparticles and a solvent. The semiconductor nanoparticles may be dispersed in the solvent and may be, for example, a colloidal dispersion.

[0232] In the semiconductor nanoparticles of the embodiment, the first compound and the second compound have a Hansen solubility parameter distance (Ra) calculated relative to a predetermined solvent, which is greater than 0, or greater than or equal to about 0.1 and less than or equal to about 4, or less than or equal to about 3.

[0233] The Hansen solubility parameter (HSP) is known as a factor for predicting whether one substance will dissolve in another to form a solution. For example, compounds with chemical structures can be used to calculate dispersion solubility parameters, polar solubility parameters, and hydrogen bond parameters. Among these, the dispersion solubility parameter δD is related to the energy arising from the dispersion forces between molecules; the polar solubility parameter δP is related to the energy from intermolecular dipole-dipole interactions; and the hydrogen bond parameter δH is related to the energy from hydrogen bonds between molecules. These three parameters can be treated as coordinates in a three-dimensional space (called Hansen space), and the distance Ra of the Hansen solubility parameter in this three-dimensional space satisfies the following equation:

[0234] Ra²=4(δD1-δD2)²+(δP1-δP2)²+(δH1-δH2)²

[0235] Ra: Hansen solubility parameter distance

[0236] δD1: Dispersion solubility parameter of the first and second compounds excluding the COO group.

[0237] δD2: Dispersion and solubility parameter of the intended solvent

[0238] δP1: Polar solubility parameter of the first and second compounds excluding the COO group.

[0239] δP2: Polar solubility parameter of the intended solvent

[0240] δH1: Hydrogen bond parameter of the first and second compounds excluding the COO group.

[0241] δH2: Hydrogen bonding parameter of the intended solvent

[0242] Hansen solubility parameters (i.e., hydrogen bond parameters, dispersion solubility parameters, and polar solubility parameters) can be readily and reproducibly obtained from the chemical structures of individual compounds using commercially available software. Such software includes (but is not limited to) HPiP (Hansen Solubility Parameters in Practice), COSMOlogic TURBOMOLE / COSMOtherm, and Solvit. These software tools take the chemical structure of each compound as input, calculate the Hansen solubility parameters, and then calculate the Ra value based on these parameters.

[0243] In the semiconductor nanoparticles of the embodiment, the solubility parameters of the first and second compounds can be determined taking into account the molar ratio between the first and second compounds included in the semiconductor nanoparticles. For example, solubility parameter values ​​of the first and second compounds can be obtained, and each solubility parameter value can be multiplied by the molar fraction of the corresponding compound in the semiconductor nanoparticle. Then, the molar fraction-weighted solubility parameter values ​​can be summed to calculate the overall solubility parameter.

[0244] The solubility parameter of a predetermined solvent can be calculated based on the chemical structure of the solvent. In the case of a mixed solvent, the solubility parameter of each component solvent can be obtained, and the solubility parameter of each component solvent can be multiplied by its mole fraction in the mixed solvent. The resulting values ​​can be summed to determine the Hansen solubility parameter of the mixed solvent.

[0245] In the embodiments, the Hansen solubility parameter distance Ra can be greater than or equal to about 0.3, greater than or equal to about 0.5, greater than or equal to about 0.7, greater than or equal to about 1, greater than or equal to about 1.2, greater than or equal to about 1.4, greater than or equal to about 1.6, greater than or equal to about 1.8, greater than or equal to about 2, greater than or equal to about 2.2, greater than or equal to about 2.4, or greater than or equal to about 2.6. The Hansen solubility parameter distance Ra can be less than or equal to about 3.8, less than or equal to about 3.6, less than or equal to about 3.4, less than or equal to about 3.2, less than or equal to about 3, less than or equal to about 2.9, less than or equal to about 2.7, less than or equal to about 2.5, less than or equal to about 2.3, less than or equal to about 2.1, less than or equal to about 1.9, less than or equal to about 1.7, less than or equal to about 1.5, or less than or equal to about 1.3.

[0246] The intended solvent may include substituted or unsubstituted aliphatic hydrocarbon solvents of C1 to C40, C5 to C30, or C8 to C12; substituted or unsubstituted alicyclic hydrocarbon solvents of C3 to C40, C6 to C30, or C8 to C12; substituted or unsubstituted aromatic hydrocarbon solvents of C6 to C50 or C8 to C36; substituted or unsubstituted aliphatic ester solvents of C6 to C50, C5 to C40, or C8 to C36; or combinations thereof (e.g., mixtures of two or more of the listed solvents). The intended solvent may include cyclohexylbenzene, hexadecane, octylbenzene, 1,3,5-triisopropylbenzene, ethyldodecanoate, decylcyclohexane, or combinations thereof.

[0247] In embodiments, the predetermined solvent may be a mixture of solvents, and the ratio (e.g., volume ratio) between the solvents may be appropriately selected. In embodiments, the predetermined solvent may be a mixture of alicyclic and aliphatic solvents, a mixture of aliphatic and aromatic solvents, a mixture of alicyclic and aromatic solvents, or a combination thereof.

[0248] The predetermined solvent may include a solvent with a relatively high boiling point. In embodiments, the predetermined solvent may have a boiling point greater than or equal to about 200°C, greater than or equal to about 210°C, greater than or equal to about 220°C, greater than or equal to about 225°C, greater than or equal to about 230°C, greater than or equal to about 235°C, greater than or equal to about 240°C, greater than or equal to about 245°C, greater than or equal to about 250°C, greater than or equal to about 255°C, greater than or equal to about 260°C, greater than or equal to about 265°C, greater than or equal to about 270°C, greater than or equal to about 275°C, greater than or equal to about 280°C, or greater than or equal to about 285°C. The boiling point of the predetermined solvent may be less than or equal to about 350°C, less than or equal to about 335°C, less than or equal to about 330°C, less than or equal to about 325°C, less than or equal to about 320°C, less than or equal to about 315°C, less than or equal to about 310°C, less than or equal to about 305°C, less than or equal to about 300°C, less than or equal to about 295°C, less than or equal to about 290°C, less than or equal to about 285°C, less than or equal to about 280°C, less than or equal to about 275°C, less than or equal to about 270°C, less than or equal to about 265°C, less than or equal to about 260°C, less than or equal to about 255°C, less than or equal to about 250°C, less than or equal to about 245°C, less than or equal to about 240°C, or less than or equal to about 235°C.

[0249] The emission layer may or may not include a predetermined solvent. The emission layer may or may not include cyclohexylbenzene, hexadecane, octylbenzene, 1,3,5-triisopropylbenzene, ethyl dodecanoate, decylcyclohexane, or combinations thereof (mixtures thereof).

[0250] Semiconductor nanoparticles can exhibit enhanced dispersibility in organic solvents (e.g., aliphatic hydrocarbon solvents such as octane or a predetermined solvent). In one embodiment, when the semiconductor nanoparticles are dispersed in octane or a predetermined solvent and measured by dynamic light scattering (DLS) analysis, the semiconductor nanoparticles can exhibit a DLS (average) particle size of less than or equal to about 600 nm, less than or equal to about 300 nm, or less than or equal to about 200 nm. The DLS (average) particle size can be less than or equal to about 200 nm, less than or equal to about 100 nm, less than or equal to about 80 nm, less than or equal to about 60 nm, less than or equal to about 50 nm, less than or equal to about 40 nm, less than or equal to about 30 nm, or less than or equal to about 20 nm. The DLS particle size can be greater than or equal to about 5 nm, greater than or equal to about 7 nm, greater than or equal to about 10 nm, greater than or equal to about 15 nm, or greater than or equal to about 20 nm.

[0251] Examples of semiconductor nanoparticles exhibit a relatively reduced organic content in thermogravimetric analysis while still exhibiting the desired degree of dispersion in organic solvents (or predetermined organic solvents). In these examples, the semiconductor nanoparticles may exhibit a weight loss in the range of 200°C to 550°C, based on the total weight of the semiconductor nanoparticles, that weight loss is less than or equal to about 13.5% by weight (wt%), less than or equal to about 13% by weight, less than or equal to about 12.5% ​​by weight, less than or equal to about 12% by weight, less than or equal to about 11.5% by weight, less than or equal to about 11% by weight, or less than or equal to about 10.5% by weight. In thermogravimetric analysis, the semiconductor nanoparticles may exhibit a weight loss in the range of 200°C to 550°C, based on the total weight of the semiconductor nanoparticles, that weight loss is greater than or equal to about 1% by weight, greater than or equal to about 3% by weight, greater than or equal to about 5% by weight, greater than or equal to about 7% by weight, greater than or equal to about 8% by weight, greater than or equal to about 9% by weight, greater than or equal to about 9.5% by weight, greater than or equal to about 10% by weight, or greater than or equal to about 10.5% by weight.

[0252] In thermogravimetric analysis, the semiconductor nanoparticles exhibit a residue content at a temperature greater than or equal to about 550°C, which, based on the total weight of the semiconductor nanoparticles, is greater than or equal to about 80 wt%, greater than or equal to about 83 wt%, greater than or equal to about 86 wt%, greater than or equal to about 86.5 wt%, greater than or equal to about 87 wt%, greater than or equal to about 88 wt%, greater than or equal to about 90 wt%, or greater than or equal to about 91 wt% and less than or equal to about 99 wt%, less than or equal to about 97 wt%, less than or equal to about 92 wt%, less than or equal to about 90 wt%, less than or equal to about 88.5 wt%, less than or equal to about 88.1 wt%, or less than or equal to about 88 wt%.

[0253] Semiconductor nanoparticles may or may not include halogens. Halogens may be fluorine, chlorine, bromine, iodine, or combinations thereof. In this embodiment, the halogen may be chlorine.

[0254] The semiconductor nanoparticles of the embodiments may include a limited amount of halogen (e.g., halide) derived from a zinc compound (e.g., zinc halide) added during synthesis. In the semiconductor nanoparticles of the embodiments, based on the total amount of all elements contained in the semiconductor nanoparticles, the halogen (or chlorine) content may be less than or equal to about 3 molar percentage (mol%), less than or equal to about 2.5 mol%, less than or equal to about 2 mol%, less than or equal to about 1.5 mol%, less than or equal to about 1 mol%, less than or equal to about 0.9 mol%, or less than or equal to about 0.8 mol%.

[0255] In semiconductor nanoparticles, based on the total molar number of sulfur, the content of halogens (or chlorine) (e.g., molar content) may be 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 8.5%, less than or equal to about 8%, less than or equal to about 7.5%, less than or equal to about 7%, less than or equal to about 6.5%, less than or equal to about 6%, less than or equal to about 5.5%, less than or equal to about 5%, less than or equal to about 4.5%, less than or equal to about 4%, less than or equal to about 3.5%, less than or equal to about 3%, or less than or equal to about 2.5%. In semiconductor nanoparticles, based on the total molar number of sulfur, the content of halogens (or chlorine) (e.g., molar content) may be greater than or equal to about 0.1%, greater than or equal to about 0.5%, greater than or equal to about 0.9%, greater than or equal to about 1.1%, greater than or equal to about 1.3%, greater than or equal to about 1.8%, greater than or equal to about 2%, greater than or equal to about 2.2%, greater than or equal to about 2.6%, greater than or equal to about 2.8%, greater than or equal to about 3.2%, or greater than or equal to about 3.6%.

[0256] The semiconductor nanoparticles may also include selenium, and based on the total number of moles of selenium, the content of halogen (or chlorine) (e.g., molar content) may be 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 8.5%, less than or equal to about 8%, less than or equal to about 7.5%, less than or equal to about 7%, less than or equal to about 6.5%, less than or equal to about 6%, less than or equal to about 5.5%, less than or equal to about 5%, less than or equal to about 4.5%, less than or equal to about 4%, less than or equal to about 3.5%, less than or equal to about 3%, or less than or equal to about 2.5%.

[0257] In semiconductor nanoparticles, based on the total number of moles of selenium, the content of halogens (or chlorine) (e.g., molar content) may be greater than or equal to about 0.1%, greater than or equal to about 0.5%, greater than or equal to about 0.9%, greater than or equal to about 1.1%, greater than or equal to about 1.3%, greater than or equal to about 1.8%, greater than or equal to about 2%, greater than or equal to about 2.2%, greater than or equal to about 2.6%, greater than or equal to about 2.8%, greater than or equal to about 3.2%, or greater than or equal to about 3.6%.

[0258] In semiconductor nanoparticles, the molar ratio of halogen (or chlorine) to zinc can be greater than or equal to about 0.005:1, greater than or equal to about 0.01:1, greater than or equal to about 0.02:1, greater than or equal to about 0.03:1, greater than or equal to about 0.04:1, greater than or equal to about 0.05:1, greater than or equal to about 0.08:1, greater than or equal to about 0.1:1, greater than or equal to about 0.15:1, or greater than or equal to about 0.2:1. In semiconductor nanoparticles, the molar ratio of halogen (or chlorine) to zinc can be less than or equal to about 1:1, less than or equal to about 0.9:1, less than or equal to about 0.7:1, less than or equal to about 0.6:1, less than or equal to about 0.4:1, less than or equal to about 0.2:1, less than or equal to about 0.12:1, less than or equal to about 0.09:1, less than or equal to about 0.07:1, less than or equal to about 0.06:1, or less than or equal to about 0.05:1.

[0259] In semiconductor nanoparticles, the molar ratio of carbon to zinc can be greater than or equal to approximately 0.005:1, greater than or equal to approximately 0.01:1, greater than or equal to approximately 0.05:1, greater than or equal to approximately 0.1:1, greater than or equal to approximately 0.15:1, greater than or equal to approximately 0.2:1, greater than or equal to approximately 0.25:1, greater than or equal to approximately 0.3:1, greater than or equal to approximately 0.35:1, greater than or equal to approximately 0.4:1, or greater than or equal to approximately 0.45:1. In semiconductor nanoparticles, the molar ratio of carbon to zinc can be less than or equal to approximately 1:1, less than or equal to approximately 0.9:1, less than or equal to approximately 0.7:1, or less than or equal to approximately 0.5:1.

[0260] As used herein, the molar ratio between elements can be determined by appropriate analytical methods, such as inductively coupled plasma atomic emission spectroscopy (ICP-AES), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy-energy dispersive X-ray spectroscopy (TEM-EDX), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX), X-ray fluorescence (XRF), etc.

[0261] Semiconductor nanoparticles may have a core-shell structure. The semiconductor nanoparticle or core-shell structure may include a first semiconductor nanocrystal (e.g., a core comprising the first semiconductor nanocrystal) and a shell disposed on the first semiconductor nanocrystal (or core). The shell may include a semiconductor nanocrystal layer comprising zinc and sulfur (comprising a third semiconductor nanocrystal). The shell may also include a second semiconductor nanocrystal comprising zinc and selenium, or an intermediate shell layer comprising the second semiconductor nanocrystal. The intermediate shell layer may be disposed between the first semiconductor nanocrystal (or core) and the semiconductor nanocrystal layer.

[0262] Semiconductor nanoparticles or first semiconductor nanocrystals may include indium phosphide, zinc indium phosphide, zinc selenide, zinc telluride, zinc telluride selenide, silver indium gallium sulfide, silver indium sulfide, or combinations thereof.

[0263] The semiconductor nanoparticles or shell may include zinc selenide, zinc telluride selenide, zinc selenide sulfide, zinc sulfide, or combinations thereof. The shell may include a first shell layer and a second shell layer (or a semiconductor nanocrystal layer), the first shell layer including a second semiconductor nanocrystal, and the second shell layer including, for example, a third semiconductor nanocrystal and disposed on the first shell layer. The first shell layer or the second semiconductor nanocrystal may include zinc selenide, zinc telluride selenide, zinc selenide sulfide, or combinations thereof. The semiconductor nanocrystal layer or the third semiconductor nanocrystal may include zinc selenide sulfide, zinc sulfide, or combinations thereof. In embodiments, the core-shell semiconductor nanoparticles may have type I, type II, or quasi-type II band alignment depending on the composition of the first semiconductor nanocrystal and the shell, and may be configured to emit light of a desired wavelength in response to voltage application or optical excitation.

[0264] In the embodiments, the semiconductor nanoparticles, the first semiconductor nanocrystals, or the shell (e.g., the second semiconductor nanocrystals or the third semiconductor nanocrystals) may each independently comprise a group II-VI compound, a group III-V compound, a group IV-VI compound, a group IV element or compound, a group II-III-VI compound, a group I-III-VI compound, a group I-II-IV-VI compound, a metal halide perovskite compound, a metal chalcogenide perovskite compound, or a combination thereof.

[0265] Group II-VI compounds may include: binary compounds (such as CdS, CdSe, CdTe, CdO, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, or combinations thereof); ternary compounds (such as CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, or combinations thereof); quaternary compounds (such as HgZnTeS, HgZnSeS, HgZnSeTe, HgZnSTe, or combinations thereof); or combinations thereof. Group II-VI compounds may also include Group III metals.

[0266] Group III-V compounds may include: binary compounds (such as GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, or combinations thereof); ternary compounds (such as GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, or combinations thereof); quaternary compounds selected from GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, or combinations thereof; or combinations thereof. Group III-V compounds may also include Group II elements. An example of such semiconductor nanocrystals is InZnP.

[0267] Group IV-VI compounds may include: binary compounds (such as SnS, SnSe, SnTe, or combinations thereof); ternary compounds (such as SnSeS, SnSeTe, SnSTe, or combinations thereof); quaternary compounds (such as SnSSeTe); or combinations thereof.

[0268] Examples of group I-III-VI compounds include (but are not limited to) CuInSe2, CuInS2, CuInGaSe, and CuInGaS. Examples of group I-III-VI semiconductor compounds may include: ternary compounds (such as AgInS, AgInS2, AgInSe2, AgGaS, AgGaS2, AgGaSe2, CuInS, CuInS2, CuInSe2, CuGaS2, CuGaSe2, CuGaO2, AgGaO2, AgAlO2, or combinations thereof); quaternary compounds (such as AgInGaS2, AgInGaSe2, or combinations thereof); or combinations thereof.

[0269] Examples of group I-II-IV-VI compounds may include (but are not limited to) CuZnSnSe and CuZnSnS.

[0270] Group IV elements or compounds may include: single elements (such as Si, Ge, or combinations thereof); binary compounds (such as SiC, SiGe, or combinations thereof); or combinations thereof.

[0271] Each element included in a multi-element compound (such as a binary, ternary, or quaternary compound) may exist within the particles in a consistent (homogeneous) or inconsistent (non-homogeneous) concentration. For example, the chemical formulas described above indicate the types of elements included in the compound, and the element ratios within the compound can vary. For example, AgInGaS2 may include AgIn. x Ga 1-x S2 (where x is a real number equal to or greater than 0 and equal to or less than 1), but not limited to this.

[0272] In one embodiment, the first semiconductor nanocrystal may include a metal selected from indium, zinc, or combinations thereof, and a nonmetal selected from phosphorus, selenium, tellurium, sulfur, or combinations thereof. In another embodiment, the second semiconductor nanocrystal may include a metal selected from indium, zinc, or combinations thereof, and a nonmetal selected from phosphorus, selenium, tellurium, sulfur, or combinations thereof.

[0273] In embodiments, the first semiconductor nanocrystal may include InP, InZnP, ZnSe, ZnSeS, ZnSeTe, or combinations thereof, and / or the second semiconductor nanocrystal may include ZnSe, ZnSeS, ZnS, ZnTeSe, or combinations thereof. In embodiments, the semiconductor nanocrystal layer may include zinc, sulfur, and optionally selenium.

[0274] In embodiments, the semiconductor nanoparticles may emit blue or green light and may have a core comprising ZnSeTe, ZnSe, or combinations thereof, and a shell comprising zinc chalcogenides (e.g., ZnS, ZnSe, and / or ZnSeS). Within the shell, the sulfur content may increase or decrease in the radial direction (from the core toward the surface).

[0275] In the embodiments, the semiconductor nanoparticles may emit red or green light, and the core may include indium phosphide (InP), indium zinc phosphide (InZnP), or a combination thereof, and the shell may include a group II metal containing zinc and a nonmetallic element containing at least one of sulfur and selenium.

[0276] In the embodiments, when the semiconductor nanoparticles have a core-shell structure, an alloy layer may or may not be present at the interface between the core and the shell. The alloy layer may be a homogeneous alloy or a gradient alloy. In a gradient alloy, the concentration of the element present in the shell may vary in the radial direction (e.g., increasing or decreasing towards the center) and may have a concentration gradient.

[0277] In embodiments, the shell may have a composition that varies in the radial direction. In embodiments, the shell may be a multilayer shell comprising two or more layers. In a multilayer shell, two adjacent layers may have different compositions. In a multilayer shell, one or more layers may each independently comprise semiconductor nanocrystals having a single composition. In a multilayer shell, one or more layers may each independently comprise alloy semiconductor nanocrystals. In a multilayer shell, one or more layers may have a compositional gradient in the radial direction regarding the composition of the semiconductor nanocrystals.

[0278] In semiconductor nanoparticles with a core-shell structure, the band gap energy of the shell material can be greater than that of the core material, but is not limited to this. The band gap energy of the shell material can also be less than that of the core material. In the case of multilayer shells, the outermost layer material can have a larger band gap compared to the materials of the core and inner shell layers (i.e., the layers closer to the core). In multilayer shells, the band gap of the semiconductor nanocrystals in each layer can be appropriately selected to effectively exhibit quantum confinement effects.

[0279] In embodiments, the semiconductor nanoparticles can be configured to control their absorption / emission wavelengths, for example, by adjusting the composition, particle size, or combinations thereof. The semiconductor nanoparticles included in the emitting layer 3 or 30 can be configured to emit light of a desired color. The semiconductor nanoparticles may include semiconductor nanoparticles that emit blue light, green light, or red light.

[0280] Semiconductor nanoparticles, emitting layers, or electroluminescent devices can emit first light. The peak emission wavelength of the first light can fall within the ultraviolet to infrared range or a wider range. For example, the peak emission wavelength of the first light emitted from semiconductor nanoparticles, emitting layers, or electroluminescent devices can be greater than or equal to about 300 nm, greater than or equal to about 500 nm, greater than or equal to about 510 nm, greater than or equal to about 520 nm, greater than or equal to about 530 nm, greater than or equal to about 540 nm, greater than or equal to about 550 nm, greater than or equal to about 560 nm, greater than or equal to about 570 nm, greater than or equal to about 580 nm, greater than or equal to about 590 nm, greater than or equal to about 600 nm, or greater than or equal to about 610 nm. The peak emission wavelength can be less than or equal to approximately 800 nm, less than or equal to approximately 650 nm, less than or equal to approximately 640 nm, less than or equal to approximately 630 nm, less than or equal to approximately 620 nm, less than or equal to approximately 610 nm, less than or equal to approximately 600 nm, less than or equal to approximately 590 nm, less than or equal to approximately 580 nm, less than or equal to approximately 570 nm, less than or equal to approximately 560 nm, less than or equal to approximately 550 nm, or less than or equal to approximately 540 nm. The peak emission wavelength can be in the range of 500 nm to 650 nm.

[0281] Semiconductor nanoparticles, emitting layers, or electroluminescent devices may emit a first light (e.g., green light) when a voltage is applied or when illuminated by light, and the peak emission wavelength of the first light or green light may be greater than or equal to about 500 nm (e.g., greater than or equal to about 510 nm, or greater than or equal to about 520 nm) and less than or equal to about 560 nm (e.g., less than or equal to about 540 nm, or less than or equal to about 530 nm). Semiconductor nanoparticles, emitting layers, or electroluminescent devices may emit a first light (e.g., red light) when a voltage is applied or when illuminated by light, and the peak emission wavelength of the first light or red light may be greater than or equal to about 600 nm (e.g., greater than or equal to about 610 nm) and less than or equal to about 650 nm (e.g., less than or equal to about 640 nm).

[0282] Semiconductor nanoparticles, emitting layers, or electroluminescent devices may emit a first light (e.g., blue light) when a voltage is applied or when illuminated by light, and the peak emission wavelength of the first light or blue light may be as described herein. The peak emission wavelength of the blue light may be greater than or equal to about 440 nm (e.g., greater than or equal to about 450 nm, or greater than or equal to about 455 nm) and less than or equal to about 480 nm (e.g., less than or equal to about 470 nm, or less than or equal to about 465 nm).

[0283] Semiconductor nanoparticles, emitting layers, electroluminescent devices, or first light may exhibit photoluminescence or electroluminescence spectra with relatively narrow full width at half maximum (FWHM). In embodiments, the semiconductor nanoparticles, emitting layers, electroluminescent devices, or first light may have an FWHM in their emission spectrum that is 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, less than or equal to about 40 nm, less than or equal to about 39 nm, less than or equal to about 38 nm, less than or equal to about 37 nm, less than or equal to about 36 nm, or less than or equal to about 35 nm.

[0284] Semiconductor nanoparticles may have a quantum yield (or absolute quantum yield) greater than or equal to about 10%, greater than or equal to about 20%, greater than or equal to about 30%, greater than or equal to about 40%, 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%, greater than or equal to about 90%, or even about 100%. In embodiments, semiconductor nanoparticles may have a quantum yield (or absolute quantum yield) greater than or equal to about 91%, greater than or equal to about 92%, greater than or equal to about 93%, greater than or equal to about 94%, greater than or equal to about 95%, greater than or equal to about 96%, or greater than or equal to about 97%.

[0285] In embodiments, the semiconductor nanoparticles may include a first compound and a second compound as defined herein, and may exhibit relatively high quantum efficiency. In embodiments, the semiconductor nanoparticles may include a first compound and a second compound, and may exhibit an absolute quantum yield greater than or equal to about 80%, greater than or equal to about 83%, greater than or equal to about 85%, greater than or equal to about 87%, greater than or equal to about 89%, greater than or equal to about 90%, greater than or equal to about 91%, greater than or equal to about 93%, or greater than or equal to about 95%.

[0286] The semiconductor nanoparticles of the embodiments may have the dimensions as described herein. The term "size" may refer to the individual size of the particle or the average size of the particle. The size may be the diameter of the particle or the equivalent diameter calculated assuming a spherical shape. For example, the size may be the diameter or equivalent diameter from an electron microscope image when the particle is not spherical, which is obtained by converting an assumed spherical shape. The size may be calculated from the results of inductively coupled plasma atomic emission spectroscopy (ICP-AES) analysis.

[0287] In embodiments, the semiconductor nanoparticles may have an average size greater than or equal to about 8 nm, greater than or equal to about 8.5 nm, greater than or equal to about 9 nm, greater than or equal to about 9.5 nm, greater than or equal to about 10 nm, greater than or equal to about 10.5 nm, greater than or equal to about 11 nm, greater than or equal to about 11.5 nm, greater than or equal to about 12 nm, greater than or equal to about 12.5 nm, greater than or equal to about 12.8 nm, greater than or equal to about 13 nm, greater than or equal to about 13.5 nm, greater than or equal to about 14 nm, or greater than or equal to about 14.2 nm. The (average) size of one or more semiconductor nanoparticles may be less than or equal to about 50 nm, for example, less than or equal to about 40 nm, less than or equal to about 35 nm, less than or equal to about 29 nm, less than or equal to about 28 nm, less than or equal to about 27 nm, less than or equal to about 26 nm, less than or equal to about 25 nm, less than or equal to about 24 nm, less than or equal to about 23 nm, less than or equal to about 22 nm, less than or equal to about 21 nm, less than or equal to about 20 nm, less than or equal to about The nanoparticles may have a size of 19 nm or less than or equal to about 18 nm, 17.5 nm or less than or equal to about 17 nm, 16.5 nm or less than or equal to about 16 nm, 15.5 nm or less than or equal to about 15 nm, 14.5 nm or less than or equal to about 14 nm, 13.5 nm or less than or equal to about 13 nm, 12.5 nm or less than or equal to about 12 nm, or 11.5 nm or less than or equal to about 11.5 nm. Here, the average value may be the arithmetic mean. The average value may also be the median. The values ​​described in this specification may include approximate values. Semiconductor nanoparticles may have a particle size greater than or equal to about 9 nm, greater than or equal to about 10 nm, or greater than or equal to about 12 nm and less than or equal to about 50 nm.

[0288] The semiconductor nanoparticles of the embodiments may have a particle size distribution (standard deviation of particle size) of about 15%, about 14%, about 13%, about 12%, or about 11% of the average value, less than or equal to the average value. This particle size distribution may be greater than or equal to about 1%, greater than or equal to about 5%, or greater than or equal to about 7%.

[0289] The size of the particles can be easily and reproducibly obtained from images of the particles taken by an electron microscope (e.g., scanning electron microscope or transmission electron microscope) using known or commercially available image analysis tools (e.g., ImageJ) according to the manufacturer's manual or similar means. There are no particular limitations on the image analysis tools and measurement conditions.

[0290] In the embodiments, semiconductor nanoparticles may be prepared according to the methods described herein.

[0291] In an embodiment, a method for manufacturing semiconductor nanoparticles includes: preparing a first semiconductor nanocrystal or particles comprising the first semiconductor nanocrystal (e.g., a first particle); and heating (e.g., to a reaction temperature) a reaction medium comprising the first semiconductor nanocrystal, a zinc precursor, a sulfur precursor, a first compound, and a second compound in an organic solvent to form a semiconductor nanocrystal layer comprising zinc and sulfur on the first semiconductor nanocrystal (or on at least a portion of the surface of the nanocrystal or particle). Forming the semiconductor nanocrystal layer may include: reacting the first medium comprising the particle, the zinc precursor, the sulfur precursor, and the second compound at a reaction temperature; and adding the first compound to the first medium.

[0292] In an embodiment, a method for manufacturing semiconductor nanoparticles includes: obtaining a reaction medium (e.g., a first medium) in an organic solvent comprising first particles containing first semiconductor nanocrystals, a second zinc precursor, and a sulfur precursor; and heating the reaction medium to a reaction temperature to form a semiconductor nanocrystal layer comprising zinc and sulfur, wherein the second zinc precursor may comprise a second compound, and the method may further include adding the first compound to the reaction medium.

[0293] In the embodiments, the addition of the first compound can be carried out at a temperature greater than or equal to about 180°C and less than the reaction temperature.

[0294] The first particle may include a second zinc chalcogenide (or a second semiconductor nanocrystal comprising the second zinc chalcogenide), the second zinc chalcogenide comprising zinc, selenium, and optionally sulfur. The second semiconductor nanocrystal, or an intermediate shell comprising the second semiconductor nanocrystal, may be disposed on the first semiconductor nanocrystal or core. Details regarding the first and second semiconductor nanocrystals are described herein.

[0295] There are no particular limitations on the formation of the first particle, and it can be appropriately selected. In embodiments, the first semiconductor nanocrystal or the core comprising the first semiconductor nanocrystal can be manufactured by a suitable method taking into account its composition and the desired properties of the final nanoparticle, or it can be commercially available.

[0296] In embodiments, the first semiconductor nanocrystal or the core comprising the first semiconductor nanocrystal may include zinc and selenium, and optionally tellurium. In embodiments, the first semiconductor nanocrystal or core may include a zinc chalcogenide comprising zinc, selenium, and tellurium, and the first semiconductor nanocrystal or core may be obtained by: preparing a zinc precursor solution comprising a first zinc precursor and an organic ligand; preparing a selenium precursor and a tellurium precursor; heating the zinc precursor solution to a nucleation reaction temperature; and adding the selenium precursor and the tellurium precursor (optionally, the selenium precursor and the tellurium precursor are added together with the organic ligand), and performing a nucleation reaction.

[0297] In embodiments, the first semiconductor nanocrystal, or a core comprising the first semiconductor nanocrystal, can be formed by a thermal injection method, in which a phosphorus precursor is injected into a solution comprising a metal precursor (such as an indium precursor) and optionally a ligand, while the solution is heated to a high temperature (e.g., to a temperature greater than or equal to about 200°C). In embodiments, the core can be prepared by a heating-up method, in which a phosphorus precursor is injected at a predetermined temperature, followed by an increase in the temperature of the reaction system.

[0298] In the nucleation reaction, the ratio between the precursors (e.g., the molar ratio of tellurium to selenium precursor) or the reaction time can be appropriately selected taking into account factors such as the emission wavelength of the final semiconductor nanoparticles, the reactivity of the precursors, and the reaction temperature. The nucleation reaction temperature can be appropriately selected. It can be greater than or equal to about 240°C, greater than or equal to about 250°C, greater than or equal to about 260°C, greater than or equal to about 270°C, greater than or equal to about 280°C, or, for example, greater than or equal to about 290°C. The reaction temperature used for nucleation can be in the range of about 280°C to about 340°C (e.g., about 290°C to about 330°C, or about 300°C to about 320°C). The reaction time used for nucleation can be adjusted taking into account the desired nucleus size and the reactivity of the precursors, and is not particularly limited. For example, the reaction time can be greater than or equal to about 5 minutes, greater than or equal to about 30 minutes, or greater than or equal to about 50 minutes, but is not limited thereto. For example, the reaction time may be less than or equal to about 2 hours, but is not limited to this. The formed nuclei may be separated from the reaction system (e.g., by non-solvent precipitation), or they may not be separated from the reaction system. The separated nuclei may optionally be washed and then added to subsequent reactions.

[0299] In embodiments, the first particle may also include a second semiconductor nanocrystal or an intermediate shell containing the second semiconductor nanocrystal on the core or the first semiconductor nanocrystal. The method for forming the second semiconductor nanocrystal or the intermediate shell containing the second semiconductor nanocrystal is not particularly limited and can be suitably selected.

[0300] In the method of the embodiment, forming a second semiconductor nanocrystal (or an intermediate shell including the second semiconductor nanocrystal) on the first semiconductor nanocrystal includes: contacting (reacting) a first zinc precursor and a chalcogen element precursor (e.g., a selenium precursor and optionally a sulfur precursor) at a reaction temperature in the presence of an organic solvent and the first semiconductor nanocrystal.

[0301] Organic solvents may include: primary amines having C6 to C22 carbon atoms (such as hexadecylamine); secondary amines having C6 to C22 carbon atoms (such as dioctylamine); tertiary amines having C6 to C40 carbon atoms (such as trioctylamine); nitrogen-containing heterocyclic compounds (such as pyridine); alkenes having C6 to C40 carbon atoms (such as octadecene); aliphatic hydrocarbons having C6 to C40 carbon atoms (such as hexadecane, octadecane, or squalane); aromatic hydrocarbons substituted with alkyl groups having C6 to C30 carbon atoms (such as phenyldodecane, phenyltetradecane, or phenylhexadecane); primary, secondary, or tertiary phosphines substituted with at least one (e.g., one, two, or three) C6 to C22 alkyl groups (e.g., trioctylphosphine); phosphine oxides substituted with one, two, or three C6 to C22 alkyl groups (e.g., trioctylphosphine oxide); aromatic ethers having C12 to C22 carbon atoms (such as phenyl ethers or benzyl ethers); or combinations thereof.

[0302] Organic ligands can coordinate to the surface of the resulting semiconductor nanoparticles, allowing the semiconductor nanoparticles to be well dispersed in solution. Organic ligands may include RCOOH, RNH2, R2NH, R3N, RSH, RH2PO, R2HPO, R3PO, RH2P, R2HP, R3P, ROH, RCOOR', RPO(OH)2, or R2POOH (wherein R and R' are each independently a substituted or unsubstituted aliphatic hydrocarbon, a substituted or unsubstituted aromatic hydrocarbon, or a combination thereof, wherein the aliphatic hydrocarbon has a carbon atom greater than or equal to about C1, greater than or equal to about C6, or greater than or equal to about C10 and less than or equal to about C40, less than or equal to about C35, or less than or equal to about C25, and the aromatic hydrocarbon has carbon atoms from C6 to C40) or combinations thereof. The ligands may be used alone or as a combination of two or more compounds.

[0303] Examples of organic ligands may include: thiols (such as methanethiol, ethanethiol, propanethiol, butanethiol, pentathiol, hexanethiol, octylthiol, dodecylthiol, hexadecylthiol, octadecylthiol, and benzylthiol); amines (such as methylamine, ethylamine, propylamine, butylamine, pentaamine, hexylamine, octylamine, nonylamine, decylamine, dodecylamine, hexadecylamine, octadecylamine, dimethylamine, diethylamine, dipropylamine, tributylamine, and trioctylamine); carboxylic acid compounds (such as formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, dodecanoic acid, hexadecanoic acid, octanoic acid, oleic acid, myristic acid, stearic acid, lauric acid, and benzoic acid); and phosphine compounds (such as methylphosphine, ethylphosphine, propionic acid, propylphosphine, etc.). Phosphorus, butylphosphine, pentylphosphine, octylphosphine, dioctylphosphine, tributylphosphine, and trioctylphosphine; phosphine compounds (such as methylphosphine oxide, ethylphosphine oxide, propylphosphine oxide, butylphosphine oxide, pentylphosphine oxide, tributylphosphine oxide, octylphosphine oxide, dioctylphosphine oxide, trioctylphosphine oxide, and diphenylphosphine (DPP) or its oxides, diphenylphosphine, triphenylphosphine compounds or their oxides); C5 to C20 alkylphosphino acids (such as hexylphosphino acid, octylphosphino acid, dodecylphosphino acid, tetradecylphosphino acid, hexadecylphosphino acid, or octadecylphosphino acid); C5 to C20 alkylphosphino acids; etc., but the examples are not limited thereto.

[0304] The first zinc precursor may include Zn metal powder, ZnO, alkylated Zn compounds (e.g., C2 to C30 dialkyl zinc (such as diethylzinc)), Zn alkoxides (e.g., zinc ethoxide), Zn carboxylates (e.g., zinc acetate), Zn nitrates, Zn perchlorates, Zn sulfates, Zn acetylacetonates, Zn halides (e.g., zinc chloride), Zn cyanides, zinc hydroxides, zinc carbonates, zinc peroxides, or combinations thereof. Examples of zinc precursors may include dimethyl zinc, diethylzinc, 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, or combinations thereof.

[0305] There are no particular limitations on the type of indium precursor, and it can be selected appropriately. Indium precursors can be indium powder, indium alkylates, indium alkoxides, indium carboxylates, indium nitrates, indium perchlorates, indium sulfates, indium acetylacetonates, indium halides, indium cyanides, indium hydroxides, indium oxides, indium peroxides, indium carbonates, or combinations thereof. Indium precursors may include indium carboxylate (such as indium oleate or indium myristate), indium acetate, indium hydroxide, indium chloride, indium bromide, and indium iodide. The formation of indium precursors can be performed 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.

[0306] 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.

[0307] Selenium precursors may include, but are not limited to, selenium-trioctylphosphine (Se-TOP), selenium-tributylphosphine (Se-TBP), selenium-triphenylphosphine (Se-TPP), selenium-diphenylphosphine (Se-DPP), or combinations thereof.

[0308] Tellurium precursors may include, but are not limited to, tellurium-tributylphosphine (Te-TBP), tellurium-triphenylphosphine (Te-TPP), tellurium-diphenylphosphine (Te-DPP), or combinations thereof.

[0309] Sulfur precursors may include hexamethylenetetramine, octanethiol, decanethiol, dodecanethiol, hexadecethiol, mercaptopropylsilane, thio-trioctylphosphine (S-TOP), thio-tributylphosphine (S-TBP), thio-triphenylphosphine (S-TPP), thio-trioctylamine (S-TOA), bis(trialkylsilyl) sulfides, bis(trialkylsilyl) alkyl sulfides (e.g., bis(trimethylsilyl) methyl sulfide), ammonium sulfide, sodium sulfide, or combinations thereof.

[0310] After synthesis and before use in subsequent reactions (e.g., reactions for forming a semiconductor nanocrystal shell comprising zinc and sulfur), the first particles comprising the first semiconductor nanocrystal and optionally the second semiconductor nanocrystal can be separated and washed according to the methods described herein. The separated and washed particles can be dispersed in a suitable organic solvent (e.g., an aromatic solvent (such as toluene) or an aliphatic hydrocarbon solvent (such as octane)) and then added to the subsequent reaction.

[0311] In embodiments of the method, a reaction medium comprising a first particle, a second zinc precursor, and a sulfur precursor in an organic solvent may be heated to a reaction temperature to form a semiconductor nanocrystal layer comprising zinc and sulfur, and a first compound may be added to the reaction medium. The first compound may be added before, during, or after the formation of the semiconductor nanocrystal layer. The second zinc precursor comprises a second compound. Detailed descriptions of the first and second compounds are as described herein. Details regarding the first particle, the sulfur precursor, the organic ligand, and the organic solvent are also as described herein.

[0312] In the embodiments, the first compound may further include metal ions, and in order to prepare the first compound, a metal compound containing metal ions (e.g., a metal acetate) and the first compound (e.g., the first compound in the form of a carboxylic acid) may (e.g., under vacuum) react at a predetermined temperature (e.g., greater than or equal to about 50°C, greater than or equal to about 100°C, greater than or equal to about 150°C and less than or equal to about 300°C, less than or equal to about 200°C, or less than or equal to about 180°C).

[0313] The reaction temperature can be appropriately selected. In an embodiment, the vacuum-treated reaction medium can be first heated to a first temperature, followed by the addition of the first particles, the second zinc precursor, and the sulfur precursor, and then the reaction medium is further heated to the reaction temperature. The first temperature can be lower than the reaction temperature. The temperature difference between the first temperature and the reaction temperature can be within the range of 10°C to 200°C, 30°C to 190°C, 50°C to 185°C, 70°C to 180°C, 80°C to 180°C, 90°C to 180°C, 100°C to 180°C, 120°C to 180°C, 140°C to 160°C, or combinations thereof.

[0314] In an embodiment, during or after forming a semiconductor nanocrystal layer of desired thickness by heating the reaction medium to the reaction temperature, the first compound may be added to the reaction medium at a second temperature. The reaction medium containing the first compound may be stirred for a predetermined time to complete the reaction.

[0315] The second temperature for adding the first compound can be greater than or equal to about 150°C, greater than or equal to about 170°C, greater than or equal to about 180°C, and less than or equal to the reaction temperature.

[0316] Surprisingly, the inventors have discovered that, in the formation of a shell comprising zinc and sulfur, semiconductor nanoparticles prepared by the methods described herein can include a first compound and a second compound in a manner disclosed herein, and can provide enhanced properties and lifetime within an electroluminescent device, while exhibiting desired dispersibility for subsequent emitter layer formation processes.

[0317] In commonly known ligand exchange reactions, the first compound may fail to achieve the desired degree of exchange due to, for example, overreaction. Surprisingly, the inventors have discovered that when the first compound is introduced into the reaction medium during or after the formation of semiconductor nanocrystals, but before the reaction is complete, in the synthesis steps of semiconductor nanoparticles, the first compound competes with the second compound for binding to the surface of the semiconductor nanoparticles, and an equilibrium is reached. As a result, the semiconductor nanoparticles prepared by the methods of the embodiments can include the first and second compounds in a stable state and have been confirmed to exhibit the desired dispersibility not only in conventional organic solvents but also in high-boiling-point solvents or solvent mixtures for inkjet printing ink compositions having the Hansen solubility parameter distance as described herein. The semiconductor nanoparticles prepared according to the methods described herein include the first and second compounds (e.g., the first and second compounds stably attached to the semiconductor nanocrystal layer at a desired ratio) and have thus been confirmed to be capable of forming stable ink compositions and high-quality emission layers.

[0318] The reaction temperature can be greater than or equal to about 250°C, greater than or equal to about 260°C, greater than or equal to about 270°C, greater than or equal to about 280°C, greater than or equal to about 300°C, greater than or equal to about 320°C, greater than or equal to about 340°C, or greater than or equal to about 350°C. The reaction temperature can be less than or equal to about 400°C, less than or equal to about 390°C, less than or equal to about 380°C, less than or equal to about 370°C, less than or equal to about 360°C, less than or equal to about 350°C, less than or equal to about 345°C, less than or equal to about 340°C, less than or equal to about 330°C, less than or equal to about 320°C, less than or equal to about 310°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 250°C. In embodiments of the method, the reaction temperature can vary within the range of about 250°C to about 340°C.

[0319] The temperature difference between the second temperature and the reaction temperature can be in the range of about 20°C to about 100°C, about 30°C to about 90°C, about 40°C to about 80°C, about 50°C to about 70°C, or about 55°C to about 65°C.

[0320] In an embodiment, the second temperature may be greater than or equal to about 155°C, greater than or equal to about 175°C, greater than or equal to about 185°C, greater than or equal to about 190°C, greater than or equal to about 195°C, greater than or equal to about 200°C, greater than or equal to about 205°C, greater than or equal to about 210°C, greater than or equal to about 220°C, greater than or equal to about 230°C, greater than or equal to about 240°C, greater than or equal to about 250°C, greater than or equal to about 260°C, greater than or equal to about 270°C, greater than or equal to about 280°C, greater than or equal to about 290°C, or greater than or equal to about 300°C. The second temperature may be less than or equal to about 380°C, less than or equal to about 360°C, less than or equal to about 340°C, less than or equal to about 320°C, less than or equal to about 300°C, less than or equal to about 295°C, less than or equal to about 285°C, less than or equal to about 275°C, less than or equal to about 265°C, less than or equal to about 255°C, or less than or equal to about 245°C.

[0321] There are no specific restrictions on the booking time, and you can choose as appropriate. Booking times can be approximately 1 minute, 3 minutes, 5 minutes, 7 minutes, or 10 minutes. Booking times can be less than or equal to 2 hours, 90 minutes, 1 hour, 50 minutes, 40 minutes, 30 minutes, or 20 minutes.

[0322] The total reaction time for forming the semiconductor nanocrystal layer can be appropriately selected taking into account the type of precursor, reaction temperature, and the desired thickness of the ZnS shell in the final semiconductor nanoparticles. The total reaction time can be greater than or equal to about 10 minutes, greater than or equal to about 15 minutes, greater than or equal to about 20 minutes, greater than or equal to about 25 minutes, greater than or equal to about 30 minutes, greater than or equal to about 35 minutes, or greater than or equal to about 40 minutes. The total reaction time can also be less than or equal to about 200 minutes, less than or equal to about 180 minutes, less than or equal to about 160 minutes, less than or equal to about 140 minutes, less than or equal to about 120 minutes, less than or equal to about 100 minutes, less than or equal to about 90 minutes, or less than or equal to about 80 minutes.

[0323] The molar ratio between the first compound and the zinc precursor (or the second compound) can be appropriately selected taking into account the reactivity of the compounds, the desired thickness of the semiconductor nanocrystal layer, and the desired ratio between the compounds.

[0324] In the embodiments, for every 1 mol of zinc precursor (second zinc precursor), the amount of the first compound may be greater than or equal to about 0.1 mol, greater than or equal to about 0.2 mol, greater than or equal to about 0.24 mol, greater than or equal to about 0.3 mol, greater than or equal to about 0.4 mol, greater than or equal to about 0.45 mol, greater than or equal to about 0.5 mol, greater than or equal to about 0.55 mol, greater than or equal to about 0.6 mol, greater than or equal to about 0.65 mol, greater than or equal to about 0.7 mol, greater than or equal to about 0.75 mol, greater than or equal to about 0.8 mol, greater than or equal to about 0.85 mol, greater than or equal to about 0.9 mol, greater than or equal to about 0.95 mol, or greater than or equal to about 1 mol. For every 1 mol of zinc precursor, the amount of the first compound can be less than or equal to about 5 mol, less than or equal to about 3 mol, less than or equal to about 2 mol, less than or equal to about 1.9 mol, less than or equal to about 1.7 mol, less than or equal to about 1.5 mol, less than or equal to about 1.3 mol, less than or equal to about 1.1 mol, or less than or equal to about 0.9 mol. The molar ratio between precursors in the reaction can be appropriately selected taking into account the reactivity of the precursors, the reaction temperature, the desired thickness of the semiconductor nanocrystal layer, etc., and there are no particular limitations.

[0325] After the reaction is complete, the first semiconductor nanocrystal, the first particle, or the resulting semiconductor nanoparticles can be recovered by adding an excess of non-solvent to remove excess organic material that is not coordinated to the surface, and by centrifuging the resulting mixture. For example, after the reaction is complete, if a non-solvent is added to the reaction product, the semiconductor nanoparticles coordinated with the ligand compound can be separated. The non-solvent can be a polar solvent that is miscible with the solvent used in the core-forming reaction and / or shell-forming reaction and cannot disperse the manufactured nanocrystals. The non-solvent can be selected according to the solvent used in the reaction and can include, for example, acetone, ethanol, butanol, isopropanol, ethylene glycol, water, tetrahydrofuran (THF), dimethyl sulfoxide (DMSO), diethyl ether, formaldehyde, acetaldehyde, ethylene glycol, solvents with similar solubility parameters to the aforementioned solvents, or combinations thereof. Separation can be performed by centrifugation, precipitation, chromatography, or distillation. If necessary, the separated nanocrystals can be added to a washing solvent and washed. There are no particular restrictions on the washing solvent, and it can have a solubility parameter similar to that of the ligand, and can include, for example, hexane, heptane, octane, chloroform, toluene, benzene, etc.

[0326] The semiconductor nanoparticles of the embodiments may be non-dispersible or insoluble in water, the aforementioned non-solvents, or combinations thereof. The semiconductor nanoparticles of the embodiments may be dispersed in the aforementioned organic solvents. In the embodiments, the semiconductor nanoparticles may be dispersed in C6 to C40 aliphatic hydrocarbons, C6 to C40 substituted or unsubstituted aromatic hydrocarbons, or combinations thereof.

[0327] The obtained semiconductor nanoparticles can exhibit the properties described herein.

[0328] The semiconductor nanoparticles of the embodiments can be used to form a composition (ink) for an inkjet printing process and to provide a patterned light-emitting layer through the inkjet printing process. In the embodiments, the composition for the inkjet process may include semiconductor nanoparticles and a liquid carrier. The semiconductor nanoparticles of the embodiments may form a colloidal dispersion within the liquid carrier. At least a portion of the liquid carrier may be removed from the light-emitting layer after the inkjet process. The liquid carrier may include an organic solvent. The organic solvent may include a dispersing solvent as described herein. The organic solvent may be an organic solvent having a relatively high boiling point at normal or atmospheric pressure. The boiling point of the organic solvent or liquid carrier may be 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, greater than or equal to about 160°C, greater than or equal to about 170°C, or greater than or equal to about 180°C. The boiling point of the organic solvent may be less than or equal to about 300°C, less than or equal to about 280°C, less than or equal to about 270°C, less than or equal to about 250°C, or less than or equal to about 200°C. Organic solvents may include substituted or unsubstituted aromatic solvents (such as cyclohexylbenzene), substituted or unsubstituted C6 to C15 aliphatic hydrocarbon solvents (such as hexane, octane, decane), or combinations thereof. When using mixed solvents, the mixing ratio may be adjusted taking into account the conditions used in the inkjet process (e.g., boiling point, viscosity, etc.). Mixed solvents may include at least one (e.g., at least two) aromatic solvents, at least one (e.g., at least two) aliphatic solvents, or at least one (e.g., at least two) aromatic solvents and at least one (e.g., at least two) aliphatic solvents. In the mixed solvents of the examples, the ratio between solvents (e.g., aromatic solvents, aliphatic solvents, or aromatic solvents and aliphatic solvents) may be adjusted to about 1:0.1 to about 1:10, about 1:0.3 to about 1:3, about 1:0.5 to about 1:2 (volume:volume), but is not limited thereto.

[0329] Ink compositions including semiconductor nanoparticles can exhibit the viscosity required in inkjet printing processes. The viscosity can be in the range of about 0.5 centipoise (cP) to about 30 cP, about 1 cP to about 15 cP, about 1.5 cP to about 10 cP, about 2 cP to about 8 cP, about 2.5 cP to about 5 cP, about 2.8 cP to about 3.5 cP, or combinations thereof.

[0330] Compositions used in inkjet printing processes may exhibit surface tension or wettability relative to a common layer (e.g., a hole-assisted layer or an electron-assisted layer). Surface tension may be in the range of about 10 millinewtons per meter (mN / m) to about 100 mN / m, about 15 mN / m to about 80 mN / m, about 20 mN / m to about 50 mN / m, about 25 mN / m to about 45 mN / m, about 30 mN / m to about 40 mN / m, about 33 mN / m to about 38 mN / m, or combinations thereof.

[0331] Forming a light-emitting layer by inkjet printing may include: placing or accommodating an ink composition comprising semiconductor nanoparticles in a device equipped with an inkjet printing nozzle, and jetting / depositing droplets of the composition from the nozzle toward a desired location (e.g., the surface of a hole transport layer or electron transport layer defined by a partition wall or dam, such as a pixel-defined layer (PDL)). (See...) Figure 4 and Figure 5 )

[0332] In the electroluminescent device of the embodiments, the thickness of the light-emitting layer may be suitably selected. In one embodiment, the light-emitting layer 3 or 30 may comprise one or more monolayers of semiconductor nanoparticles. In another embodiment, the light-emitting layer 3 or 30 may comprise one or more monolayers of semiconductor nanoparticles (e.g., two or more layers, three or more layers, or four or more layers, and 20 or fewer layers, 10 or fewer layers, 9 or fewer layers, 8 or fewer layers, 7 or fewer layers, or 6 or fewer layers). The light-emitting layer 3 or 30 may have a thickness greater than or equal to about 5 nm (e.g., greater than or equal to about 10 nm, greater than or equal to about 20 nm, or greater than or equal to about 30 nm) and less than or equal to about 200 nm (e.g., less than or equal to about 150 nm, less than or equal to about 100 nm, less than or equal to about 90 nm, less than or equal to about 80 nm, less than or equal to about 70 nm, less than or equal to about 60 nm, or less than or equal to about 50 nm). The light-emitting layer may have a thickness of, for example, about 10 nm to about 150 nm, for example, about 20 nm to about 100 nm, for example, about 30 nm to about 50 nm, or a combination thereof.

[0333] Forming a light-emitting layer comprising semiconductor nanoparticles can be performed by obtaining a composition comprising semiconductor nanoparticles and an organic solvent, and applying or depositing the composition onto a substrate or charge-assisted layer via a suitable method (e.g., via spin coating, inkjet printing, etc.). Forming the light-emitting layer may also include heat-treating the applied or deposited semiconductor nanoparticle layer. The heat-treating temperature is not particularly limited and can be appropriately selected taking into account factors such as the boiling point of the organic solvent. For example, the heat-treating temperature may be greater than or equal to about 60°C (e.g., greater than or equal to about 70°C) and less than or equal to about 250°C, or less than or equal to about 180°C. The type of organic solvent is not particularly limited and can be appropriately selected. In embodiments, the organic solvent may include (substituted or unsubstituted) aliphatic hydrocarbon organic solvents, (substituted or unsubstituted) aromatic hydrocarbon organic solvents, acetate solvents, or combinations thereof.

[0334] The emitting layer may be a single layer or a multilayer structure in which two or more layers are stacked. Adjacent layers in the multilayer structure (e.g., a first emitting layer and a second emitting layer) may be configured to emit light of the same color (green, blue, or red). In the multilayer structure, adjacent layers (e.g., a first emitting layer and a second emitting layer) may have the same or different compositions and / or ligands.

[0335] Electroluminescent devices may include a charge (hole or electron) auxiliary layer between a first electrode and a second electrode (e.g., first electrode 10 and second electrode 50). For example, an electroluminescent display device may include a hole auxiliary layer (HTL) 20 between the first electrode 10 and the light-emitting layer 30 and / or an electron auxiliary layer (ETL) 40 between the second electrode 50 and the light-emitting layer 30 (see reference). Figure 2 and Figure 3 ).

[0336] The light-emitting device according to the embodiment may further include a hole auxiliary layer. The hole auxiliary layer 20 may be disposed between the first electrode 10 and the light-emitting layer 30. The hole auxiliary layer 20 may include a hole injection layer, a hole transport layer, and / or an electron (or hole) blocking layer. The hole auxiliary layer 20 may be a single-component layer or a multilayer structure in which adjacent layers include different components.

[0337] To enhance the mobility of holes transferred from the hole assist layer 20 to the light-emitting layer 30, the hole assist layer 20 may have HOMO levels that match the HOMO levels of the light-emitting layer 30 (e.g., 30R, 30G, or 30B). In an embodiment, the hole assist layer 20 may include a hole injection layer near the first electrode 10 and a hole transport layer near the light-emitting layer 30.

[0338] The materials included in the hole assist layer 20 (e.g., hole transport layer, hole injection layer, or electron blocking layer) are not particularly limited and may include at least one of the following: for example, poly(9,9-dioctyl-fluorene-co-N-(4-butylphenyl)-diphenylamine) (TFB), polyarylamine, poly(N-vinylcarbazole), poly(3,4-ethylenedioxythiophene) (PEDOT), poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), polyaniline, polypyrrole, fluorene arylamine compounds, N,N,N',N'-tetra(4-methyl) (Oxyphenyl)-benzidine (TPD), 4,4'-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl (α-NPD), m-MTDATA (4,4',4''-tris[phenyl(m-tolyl)amino]triphenylamine), 4,4',4"-tris(N-carbazolyl)-triphenylamine (TCTA), 1,1-bis[di(4-tolyl)aminophenyl]cyclohexane (TAPC), p-type metal oxides (e.g., NiO, WO3, MoO3, etc.), carbon-containing materials (such as graphene oxide), or combinations thereof, but not limited thereto.

[0339] In one or more hole-assisted layers, the thickness of each layer may be appropriately selected. For example, the thickness of each layer may be greater than or equal to about 5 nm, greater than or equal to about 10 nm, greater than or equal to about 15 nm, or greater than or equal to about 20 nm and less than or equal to about 100 nm, less than or equal to about 90 nm, less than or equal to about 80 nm, less than or equal to about 70 nm, less than or equal to about 60 nm, less than or equal to about 50 nm, less than or equal to about 40 nm, less than or equal to about 35 nm, or less than or equal to about 30 nm, but is not limited thereto.

[0340] An electron auxiliary layer 40 may be disposed between the light-emitting layer 30 and the second electrode 50. The electron auxiliary layer 40 may include, for example, an electron injection layer, an electron transport layer, and / or a hole (or electron) blocking layer. The electron auxiliary layer may include, for example, an electron injection layer (EIL) that promotes electron injection, an electron transport layer (ETL) that promotes electron transport, a hole blocking layer (HBL) that inhibits hole transport, or a combination thereof.

[0341] In this embodiment, the electron injection layer may be disposed between the electron transport layer and the second electrode. For example, a hole blocking layer may be disposed between the emitter layer and the electron transport (injection) layer, but is not limited thereto. The thickness of each layer may be appropriately selected. For example, the thickness of each layer may be greater than or equal to about 1 nm and less than or equal to about 500 nm, but is not limited thereto. The electron injection layer may be an organic layer formed by deposition. The electron transport layer may include inorganic oxide nanoparticles, or may be an organic layer formed by deposition.

[0342] The electron transport layer (ETL), electron injection layer (EIL), and / or hole blocking layer may include, for example, 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA), bath copper (BCP), tris[3-(3-pyridyl)-trimethylmethyl]borane (3TPYMB), LiF, tris(8-hydroxyquinoline)aluminum (Alq3), tris(8-hydroxyquinoline)gallium (Gaq3), tris(8-hydroxyquinoline)indium (Inq3), bis(8-hydroxyquinoline)zinc (… Zinc(2-(2-hydroxyphenyl)benzothiazole)zinc (or bis[2-(2-benzothiazole)phenol]zinc) (Zn(BTZ)2), beryllium(10-hydroxybenzo[h]quinoline) (BeBq2), 8-(4-(4,6-di(naphthyl-2-yl)-1,3,5-triazin-2-yl)phenyl)quinolone (ET204), lithium 8-hydroxyquinoline (Liq), n-type metal oxides (e.g., ZnO, HfO2, etc.) and combinations thereof, but not limited thereto.

[0343] The electron auxiliary layer 40 may include an electron transport layer. The electron transport layer may include multiple nanoparticles. The multiple nanoparticles may include a zinc-containing metal oxide.

[0344] Metal oxides may include zinc oxide, zinc magnesium oxide, or combinations thereof. Metal oxides may include Zn. 1-x M x O (where M is Mg, Ca, Zr, W, Li, Ti, Y, Al or a combination thereof, and 0 ≤ x ≤ 0.5). In the examples, Zn 1-x M x M in O can be magnesium (Mg). In the examples, Zn 1-x M x x in O can be greater than or equal to about 0.01 and less than or equal to about 0.3 (e.g., less than or equal to about 0.25, less than or equal to about 0.2, or less than or equal to about 0.15).

[0345] The absolute value of the LUMO of the aforementioned nanoparticles included in the light-emitting layer may be greater than or less than the absolute value of the LUMO of the metal oxide. The average size of the nanoparticles may be 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, or greater than or equal to about 3 nm and 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 nm, or less than or equal to about 5 nm.

[0346] In embodiments, the thickness of each of the electron auxiliary layers 40 (e.g., an electron injection layer, an electron transport layer, or a hole blocking layer) may be greater than or equal to about 5 nm, greater than or equal to about 6 nm, greater than or equal to about 7 nm, greater than or equal to about 8 nm, greater than or equal to about 9 nm, greater than or equal to about 10 nm, greater than or equal to about 11 nm, greater than or equal to about 12 nm, greater than or equal to about 13 nm, greater than or equal to about 14 nm, greater than or equal to about 15 nm, greater than or equal to about 16 nm, or greater than or equal to... The wavelengths are approximately 17 nm, greater than or equal to approximately 18 nm, greater than or equal to approximately 19 nm, or greater than or equal to approximately 20 nm and less than or equal to approximately 120 nm, less than or equal to approximately 110 nm, less than or equal to approximately 100 nm, less than or equal to approximately 90 nm, less than or equal to approximately 80 nm, less than or equal to approximately 70 nm, less than or equal to approximately 60 nm, less than or equal to approximately 50 nm, less than or equal to approximately 40 nm, less than or equal to approximately 30 nm, or less than or equal to approximately 25 nm, but are not limited thereto.

[0347] The device according to the embodiment may have a general structure. In the embodiment, in the device, the first electrode 10 disposed on the transparent substrate 100 may include a transparent electrode containing a metal oxide (e.g., an indium tin oxide (ITO) electrode), and the second electrode (cathode) 50 facing the first electrode 10 may include a conductive metal (e.g., a conductive metal with a relatively low work function, such as Mg, Al, etc.). A hole-assisted layer 20 (e.g., a hole injection layer such as poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) and / or a p-type metal oxide, and / or a hole transport layer such as 2-(trifluoromethyl)benzimidazole (TFB) and / or polyvinylcarbazole (PVK)) may be disposed between the first electrode 10 and the light-emitting layer 30. The hole injection layer may be disposed near the transparent electrode, and the hole transport layer may be disposed near the light-emitting layer. An electron-assisted layer 40 (e.g., an electron injection / transport layer) may be disposed between the light-emitting layer 30 and the second electrode 50. (See...) Figure 2 )

[0348] The device according to another embodiment may have an inverted structure. As used herein, the second electrode 50 disposed on the transparent substrate 100 may include a transparent electrode containing a metal oxide (e.g., ITO), and the first electrode 10 facing the second electrode 50 may include a metal (e.g., a metal with a relatively high work function, Au, Ag, etc.). For example, an n-type metal oxide (optionally, a doped n-type metal oxide) (crystalline Zn metal oxide) may be disposed as an electron auxiliary layer 40 (e.g., an electron transport layer) between the second electrode 50 and the light-emitting layer 30. MoO3 or other p-type metal oxides may be disposed as a hole auxiliary layer 20 (e.g., a hole transport layer including TFB and / or PVK, and / or a hole injection layer including MoO3 or other p-type metal oxides) between the first electrode 10 and the light-emitting layer 30. (Ref.) Figure 3 )

[0349] The aforementioned device can be manufactured by suitable methods. For example, an electroluminescent device can be manufactured by forming a hole-assist layer on a substrate on which electrodes are optionally disposed (e.g., via deposition or coating), forming a light-emitting layer comprising nanoparticles (e.g., a pattern of the aforementioned semiconductor nanoparticles), and forming electrodes (optionally, an electron-assist layer and electrodes) on the light-emitting layer (e.g., via vapor deposition or coating). The method for forming the electrodes / hole-assist layer / electron-assist layer can be suitably selected and is not particularly limited. In embodiments, various methods (such as vacuum deposition, spin coating, casting, Langmuir-Blodgett (LB) method, inkjet printing, laser printing, laser-induced thermal imaging (LITI), etc.) can be used to form each layer included in the hole transport region, each layer included in the light-emitting layer, and each layer included in the electron transport region in a predetermined area. For example, the light-emitting layer can be formed by inkjet printing. The inkjet process is as described herein.

[0350] In this embodiment, each layer comprising the hole transport region, the light-emitting layer, and each layer comprising the electron transport region are formed by vacuum deposition, and the deposition conditions can be appropriately selected. For example, the deposition temperature can be from about 100°C to about 500°C, and the vacuum level can be about 10... -8 torr to about 10 -3 The deposition rate can range from about 0.01 Å / sec to about 100 Å / sec. The deposition conditions can be selected by taking into account the materials to be included in the layer to be formed and the structure of the layer to be formed.

[0351] The electroluminescent device can be configured to emit blue light. The wavelength range of blue light is as described above. The electroluminescent device can be configured to emit green light. The wavelength range of green light is as described above. The electroluminescent device can be configured to emit red light. The wavelength range of red light is as described above.

[0352] Electroluminescent devices may have a maximum external quantum efficiency of about 4%, about 5%, about 5.3%, about 5.4%, about 6%, about 7%, about 8%, about 9%, about 10%, about 10.5%, about 11%, about 11.5%, about 12%, about 12.5%, about 13%, about 13.5%, or about 14%. Electroluminescent devices may have a maximum external quantum efficiency of less than or equal to about 50%, less than or equal to about 40%, less than or equal to about 30%, or less than or equal to about 20%.

[0353] Electroluminescent devices can have a density greater than or equal to approximately 1000 nits (cd / m²). 2 Maximum brightness of approximately 3,000 nits, 10,000 nits, 40,000 nits, 50,000 nits, 60,000 nits, 70,000 nits, 80,000 nits, 90,000 nits, 95,000 nits, 100,000 nits, 105,000 nits, 110,000 nits, 115,000 nits, 120,000 nits, or 125,000 nits or more. Maximum brightness can be from approximately 3,000 nits to approximately 500,000 nits.

[0354] Electroluminescent devices can exhibit improved lifetime. In an embodiment, the lifetime of the electroluminescent device can be measured while being driven at a predetermined initial brightness (e.g., about 146 nits or about 650 nits).

[0355] The lifetime T50 of electroluminescent devices can be greater than or equal to about 10 hours, greater than or equal to about 50 hours, greater than or equal to about 80 hours, greater than or equal to about 100 hours, greater than or equal to about 120 hours, greater than or equal to about 130 hours, greater than or equal to about 150 hours, greater than or equal to about 160 hours, greater than or equal to about 200 hours, greater than or equal to about 250 hours, greater than or equal to about 260 hours, greater than or equal to about 270 hours, greater than or equal to about 300 hours, or greater than or equal to [other values]. Approximately 308 hours, greater than or equal to approximately 310 hours, greater than or equal to approximately 320 hours, greater than or equal to approximately 350 hours, greater than or equal to approximately 380 hours, greater than or equal to approximately 400 hours, greater than or equal to approximately 450 hours, greater than or equal to approximately 500 hours, greater than or equal to approximately 600 hours, greater than or equal to approximately 700 hours, greater than or equal to approximately 800 hours, greater than or equal to approximately 900 hours, greater than or equal to approximately 1000 hours, greater than or equal to approximately 1500 hours, or longer.

[0356] The lifetime T90 of electroluminescent devices can be greater than or equal to about 10 hours, greater than or equal to about 15 hours, greater than or equal to about 20 hours, greater than or equal to about 25 hours, greater than or equal to about 30 hours, greater than or equal to about 33 hours, greater than or equal to about 35 hours, greater than or equal to about 40 hours, greater than or equal to about 45 hours, greater than or equal to about 50 hours, greater than or equal to about 75 hours, greater than or equal to about 100 hours, greater than or equal to about 125 hours, greater than or equal to about 150 hours, greater than or equal to about 175 hours, greater than or equal to about 18 hours, and greater than or equal to about 18 hours. 0 hours, greater than or equal to about 200 hours, greater than or equal to about 210 hours, greater than or equal to about 300 hours, greater than or equal to about 310 hours, greater than or equal to about 350 hours, greater than or equal to about 380 hours, greater than or equal to about 400 hours, greater than or equal to about 450 hours, greater than or equal to about 500 hours, greater than or equal to about 600 hours, greater than or equal to about 700 hours, greater than or equal to about 800 hours, greater than or equal to about 900 hours, greater than or equal to about 1000 hours, greater than or equal to about 1500 hours, or longer.

[0357] In embodiments, T50 may be about 150 hours to about 5000 hours, about 400 hours to about 4000 hours, about 500 hours to about 3500 hours, about 750 hours to about 2000 hours, about 1000 hours to about 1500 hours, or a combination thereof.

[0358] In embodiments, T90 may be within the range of about 13 hours to about 5000 hours, about 15 hours to about 2800 hours, about 18 hours to about 1200 hours, about 22 hours to about 1000 hours, about 31 hours to about 800 hours, about 50 hours to about 700 hours, about 60 hours to about 500 hours, about 80 hours to about 400 hours, or combinations thereof.

[0359] In an embodiment, the display device (e.g., a display panel) includes the electroluminescent device described herein.

[0360] A display device (e.g., a display panel) may include a first pixel and a second pixel configured to emit light of a different color than the first pixel. In an embodiment, the first light from the light-emitting layer may be extracted via a second electrode (e.g., in the z-direction) (see reference). Figure 4 or Figure 5 In one embodiment, the first light can be extracted via a (transparent) first electrode and an optional substrate 100 (see reference). Figure 3 The light-emitting layer may be arranged within the pixels (or subpixels) of the display device (display panel) described later (see reference). Figure 4 or Figure 5 ).

[0361] Reference Figure 6 According to an embodiment, the display panel 1000 may include a display area 1000D for displaying images and an optional non-display area 1000P located around the display area 1000D and having an adhesive material disposed thereon.

[0362] Display area 1000D may include a plurality of pixels PX arranged along rows (e.g., in the x-direction) and / or along columns (e.g., in the y-direction), and each pixel PX may include a plurality of sub-pixels PX1, PX2, and PX3 displaying different colors. Here, as an example, a configuration in which three sub-pixels PX1, PX2, and PX3 form a pixel is shown, but this disclosure is not limited thereto, and may also include additional sub-pixels (such as white sub-pixels), or may also include one or more sub-pixels displaying the same color. The plurality of sub-pixels PX1, PX2, and PX3 may be arranged, for example, in a Bayer matrix, a PenTile matrix, and / or a diamond matrix, but are not limited thereto.

[0363] Each sub-pixel PX1, PX2, and PX3 can display a color from the three primary colors or a combination of the three primary colors (e.g., red, green, blue, or combinations thereof). For example, the first sub-pixel PX1 can display red, the second sub-pixel PX2 can display green, and the third sub-pixel PX3 can display blue.

[0364] Although the accompanying drawings show an example in which all subpixels have the same size, this disclosure is not limited thereto, and at least one subpixel may be larger or smaller than the other subpixels. Although the accompanying drawings show an example in which all subpixels have the same shape, this disclosure is not limited thereto, and at least one subpixel may have a different shape from the other subpixels.

[0365] In an embodiment, the display panel may include a light-emitting panel (see reference). Figure 7 The light-emitting panel includes a substrate 110, a buffer layer 111, a thin-film transistor (TFT), and light-emitting devices 180. The display panel may include circuit elements for switching and / or driving each light-emitting device.

[0366] Reference Figure 7 In the light-emitting panel, light-emitting devices 180 may be arranged in each sub-pixel PX1, PX2, and PX3, and the light-emitting devices 180 arranged in the sub-pixels PX1, PX2, and PX3 may be driven independently. Sub-pixels may include blue pixels, red pixels, or green pixels. At least one of the light-emitting devices 180 may be an electroluminescent device according to an embodiment.

[0367] The substrate 110 is as described above. The buffer layer 111 may comprise organic, inorganic, or organic-inorganic materials, and may comprise, for example, oxides, nitrides, or oxynitrides, and may comprise, for example, silicon oxide, silicon nitride, silicon oxynitride, or combinations thereof, but is not limited thereto. The buffer layer 111 may have one layer or two or more layers, and may cover the entire surface of the substrate 110. The buffer layer 111 may be omitted.

[0368] The thin-film transistor (TFT) can be a three-terminal device used for switching and / or driving the light-emitting device 180, and one or more TFTs may be included for each sub-pixel. The TFT includes a gate electrode 124, a semiconductor layer 154 stacked with the gate electrode 124, a gate insulating film 140 between the gate electrode 124 and the semiconductor layer 154, and a source electrode 173 and a drain electrode 175 electrically connected to the semiconductor layer 154. A coplanar top-gate structure is shown as an example, but is not limited thereto, and the TFT may have various structures.

[0369] The gate electrode 124 is electrically connected to the gate line (not shown) and may include, but is not limited to, a low-resistance metal (such as aluminum (Al), molybdenum (Mo), copper (Cu), titanium (Ti), silver (Ag), gold (Au), alloys thereof, or combinations thereof).

[0370] Semiconductor layer 154 may be: inorganic semiconductor (such as amorphous silicon, polycrystalline silicon, oxide semiconductor); organic semiconductor; organic-inorganic semiconductor; or a combination thereof. For example, semiconductor layer 154 may include an oxide semiconductor comprising at least one of indium (In), zinc (Zn), tin (Sn), and gallium (Ga), and the oxide semiconductor may include, for example, indium-gallium-zinc oxide, zinc-tin oxide, or a combination thereof, but is not limited thereto. Semiconductor layer 154 may include a channel region and a doped region, the doped region being disposed on both sides of the channel region and electrically connected to the source electrode 173 and the drain electrode 175, respectively.

[0371] The gate insulating film 140 may comprise organic, inorganic, or organic-inorganic materials, and may include, for example, oxides, nitrides, or oxynitrides, and may include, for example, silicon oxide, silicon nitride, silicon oxynitride, or combinations thereof, but is not limited thereto. The accompanying drawings illustrate an example in which the gate insulating film 140 is formed over the entire surface of the substrate 110, but are not limited thereto, and the gate insulating film 140 may be selectively formed between the gate electrode 124 and the semiconductor layer 154. The gate insulating film 140 may have one layer or two or more layers.

[0372] The source electrode 173 and drain electrode 175 may comprise, but are not limited to, low-resistance metals (such as aluminum (Al), molybdenum (Mo), copper (Cu), titanium (Ti), silver (Ag), gold (Au), alloys thereof, or combinations thereof). The source electrode 173 and drain electrode 175 may each be electrically connected to a doped region of the semiconductor layer 154. The source electrode 173 may be electrically connected to a data line (not shown), and the drain electrode 175 may be electrically connected to the light-emitting device 180, which will be described later.

[0373] An interlayer insulating film 145 may be additionally formed between the gate electrode 124 and the source electrode 173 and drain electrode 175. The interlayer insulating film 145 may comprise organic materials, inorganic materials, or organic-inorganic materials, and may include, for example, oxides, nitrides, or oxynitrides, and may include, for example, silicon oxide, silicon nitride, silicon oxynitride, or combinations thereof, but is not limited thereto. The interlayer insulating film 145 may have one layer or two or more layers.

[0374] In an embodiment, a protective film 160 may be formed on a thin-film transistor (TFT). The protective film 160 may be, for example, a passivation film, but is not limited thereto. The protective film 160 may comprise organic materials, inorganic materials, or organic-inorganic materials, and may comprise, but is not limited to, polyacrylic acid, polyimide, polyamide, polyamide-imide, or combinations thereof. The protective film 160 may have one or more layers.

[0375] In an embodiment, one of the first electrodes 1 and 10 and the second electrodes 5 and 50 may be a pixel electrode connected to a thin-film transistor TFT, and the other may be a common electrode.

[0376] The electroluminescent device or display device including the electroluminescent device in the embodiments can be used in a top-emitting mode, a bottom-emitting mode, a dual-sided emitting mode, or a combination thereof.

[0377] In one embodiment, the first electrodes 1 and 10 can be light-transmitting electrodes, and the second electrodes 5 and 50 can be reflective electrodes. The display panel can be a bottom-emitting type display panel that emits light toward the first electrode 10 and (if present) the substrate 110. In another embodiment, the first electrodes 1 and 10 can be reflective electrodes, and the second electrodes 5 and 50 can be light-transmitting electrodes. The display panel can be a top-emitting type display panel that emits light opposite to the first electrode 10 and (if present) the substrate 100. In yet another embodiment, both the first and second electrodes can be light-transmitting electrodes, and the display panel 1000 can be a two-sided emitting type display panel that emits light toward the substrate 110 side and the opposite side of the substrate 110.

[0378] Display devices may include or may be devices or equipment such as: virtual reality / augmented reality (VR / AR) devices, wearable devices, portable terminal devices, monitors, computers, laptops, sensors, televisions, electronic display panels, cameras, or (for example, automotive) electronic components.

[0379] Specific examples are shown below. However, these examples are exemplary, and this disclosure is not limited thereto.

[0380] Example

[0381] Analytical methods

[0382] 1. Photoluminescence (PL) analysis and TRPL analysis

[0383] The photoluminescence spectra and absolute quantum yield (QY) of nanoparticles were obtained at room temperature using a Hitachi F-7000 spectrophotometer or a Hamamatsu QY spectrophotometer (Quantaurus-QY absolute PL quantum yield spectrophotometer C11347-11) with an excitation wavelength of 372 nm.

[0384] 2. GC Analysis

[0385] Gas chromatography analysis was performed using an Agilent GC-MS 7890B / 5977A. No standards were used.

[0386] After separating the crude product containing the manufactured semiconductor nanoparticles twice with ethanol (EtOH) and vacuum drying, 0.1 mg of the manufactured semiconductor nanoparticles was mixed with 1 μL of TMAH (tetramethylammonium hydroxide) and left in a hood for 2 minutes before performing py-GC / MS measurements.

[0387] Pyrolysis unit temperature: 450℃

[0388] Column: 30m × 0.25mm × 0.25mm (UA5)

[0389] Mobile phase: He2 (1 mL / min)

[0390] Inlet temperature: 300℃

[0391] Furnace temperature: 50℃ (hold for 2 minutes), then increase to 320℃ at a rate of 20℃ / min (hold for 10 minutes).

[0392] Analyzer: Quadrupole type (range: 10 m / z to 550 m / z)

[0393] 3. TGA

[0394] Thermogravimetric analysis was performed using a Trios V3.2 system (TA Instruments) under nitrogen atmosphere at a heating rate of 10 °C / min from 20 °C to 600 °C. The weight loss from 200 °C to 550 °C was measured as the organic matter content.

[0395] 4. Electroluminescence measurement and lifetime

[0396] The current was measured according to the applied voltage using a Keithley 2635B source meter, and the electroluminescence properties (e.g., luminance and EQE) of the light-emitting device were measured using a CS2000 spectrometer.

[0397] T90(h): The time (in hours) taken for the brightness to reach 90% of the initial brightness when driven at a predetermined brightness (e.g., 650 nit or 146 nit).

[0398] T50(h): The time (in hours) taken for the brightness to reach 50% of the initial brightness when driven at a predetermined brightness (e.g., 650 nit or 146 nit).

[0399] The following synthesis is performed under an inert gas atmosphere (e.g., under nitrogen) unless otherwise specified. Precursor content is provided in molar amounts unless otherwise specified.

[0400] Reference Example 1: Synthesis of ZnMgO Nanoparticles

[0401] Zinc acetate dihydrate and magnesium acetate tetrahydrate were added to a reactor containing dimethyl sulfoxide and then heated to 60°C under air. Subsequently, an ethanol solution of tetramethylammonium hydroxide pentahydrate was added to the reactor. After stirring the mixture for 1 hour, the precipitate was centrifuged and then dispersed in ethanol to obtain Zn. 1-x Mg x O nanoparticles (x=0.15).

[0402] The obtained nanoparticles were analyzed by transmission electron microscopy. The results confirmed that the nanoparticles have an average size of approximately 3 nm.

[0403] Reference Example 2: Manufacturing of the First Particle

[0404] Selenium (Se), sulfur (S), and tellurium (Te) were dispersed in trioctylphosphine (TOP) to obtain a 2 mol / L (M) Se / TOP stock solution, a 1 M S / TOP stock solution, and a 0.1 M Te / TOP stock solution.

[0405] 4.5 mmol of zinc acetate was added together with oleic acid (OA) into a 300 mL reaction flask containing trioctylamine (TOA), and then heated to 120 °C under vacuum. After 1 hour, the atmosphere inside the reactor was converted to an inert gas.

[0406] After heating the flask to 240°C to 300°C, the prepared Se / TOP and Te / TOP stock solutions were rapidly injected into the flask at a Te / Se ratio of 1 / 15. The reaction proceeded for 40 minutes. When the reaction was complete, the reaction solution was rapidly cooled to room temperature, and ethanol was added to the reaction solution. Then, centrifugation was performed to obtain ZnTeSe semiconductor nanocrystals. The obtained precipitate was dispersed in hexane to obtain ZnSeTe cores. The cores had an average size of approximately 3 nm.

[0407] Zinc acetate and oleic acid were added together to a 300 mL reaction flask containing TOA, and then the mixture was vacuum-treated at 120 °C. Nitrogen (N2) was used to replace the internal atmosphere of the flask. The reaction flask was heated to a reaction temperature of 340 °C. After the hexane dispersion of the ZnSeTe core was rapidly added to the reaction flask, a Se / TOP stock solution was subsequently added to initiate the reaction. To form the ZnSe shell, a selenium precursor was used at a rate of 0.67 mol per mol of zinc precursor.

[0408] After the reaction was complete, the reactor was cooled to room temperature, and ethanol was added to the reaction solution to precipitate first particles comprising first semiconductor nanocrystals (ZnTeSe) and second semiconductor nanocrystals (ZnSe). The precipitate was recovered by centrifugation.

[0409] Preparation Example 1:

[0410] Zinc acetate and oleic acid were added to trioctylamine, and then heated at 120°C for 1 hour under vacuum to prepare a second zinc precursor.

[0411] After adding trioctylamine to a 300 mL reaction flask, the flask was heated to 120 °C under vacuum for 1 hour, and then the atmosphere inside the flask was replaced with nitrogen (N2). While raising the flask temperature to the reaction temperature (340 °C), a hexane dispersion of the first particles prepared in Reference Example 2 was added. Subsequently, the second zinc precursor and dodecyl mercaptan (sulfur precursor) were added to the reaction system as two separate portions.

[0412] After 40 minutes, the reaction temperature was lowered to 280°C, and 4-phenylbutyric acid (4PhBA) (CAS No. 1821-12-1, manufactured by Sigma-Aldrich) with the following chemical formula was injected into the reaction system, and the reaction continued:

[0413]

[0414] The total reaction time is 70 minutes.

[0415] The molar ratio of the second zinc precursor to the sulfur precursor is 2.5:1.4. The molar ratio of the second zinc precursor to phenylbutyric acid is 2.5:0.6.

[0416] After cooling the reactor to room temperature, ethanol was added to the reaction solution to promote the precipitation of semiconductor nanoparticles, which were then recovered by centrifugation. The obtained semiconductor nanoparticles were dispersed in octane.

[0417] Photoluminescence spectroscopy and thermogravimetric analysis (TGA) were performed on the obtained semiconductor nanoparticles, and the results are summarized in Table 1.

[0418] The obtained semiconductor nanoparticles were analyzed by gas chromatography (GC), and the results are summarized in Table 2.

[0419] According to GC-MS analysis, a first peak corresponding to the phenylbutyrate fraction was identified at a retention time of 9.05 minutes, and a second peak corresponding to the oleate fraction was identified at a retention time of 13.13 minutes.

[0420] Preparation Example 2:

[0421] Semiconductor nanoparticles were fabricated in the same manner as in Preparation Example 1, except that 6-phenylhexanoic acid (6PhHA) (phenylhexanoic acid, CAS No. 5581-75-9, manufactured by Sigma Aldrich) was used instead of 4-phenylbutyric acid:

[0422]

[0423] The reactor was cooled to room temperature, and ethanol was added to the reaction solution to promote the precipitation of semiconductor nanoparticles. The semiconductor nanoparticles were then recovered by centrifugation. The obtained semiconductor nanoparticles were dispersed in octane.

[0424] Photoluminescence spectroscopy and TGA were performed on the obtained semiconductor nanoparticles, and the results are summarized in Table 1.

[0425] GC analysis was performed on the obtained semiconductor nanoparticles, and the results are summarized in Table 2. According to GC-MS analysis, a first peak belonging to the phenylhexanoate moiety was observed at a retention time of 10.41 min, and a second peak belonging to the oleate moiety was observed at a retention time of 13.13 min.

[0426] Preparation Examples 3-1 and 3-2:

[0427] Semiconductor nanoparticles were prepared in the same manner as in Preparation Example 2, except that the amount of 6-phenylhexanoic acid (phenylhexanoic acid, CAS No. 5581-75-9, manufactured by Sigma Aldrich) was increased by two times (Preparation Example 3-1) or four times (Preparation Example 3-2).

[0428] The reactor was cooled to room temperature, and ethanol was added to the reaction solution to promote the precipitation of semiconductor nanoparticles. The semiconductor nanoparticles were then recovered by centrifugation. The obtained semiconductor nanoparticles were dispersed in octane.

[0429] Photoluminescence spectroscopy and TGA were performed on the obtained semiconductor nanoparticles, and the results are summarized in Table 1.

[0430] GC analysis was performed on the obtained semiconductor nanoparticles, and the results are summarized in Table 2. According to GC-MS analysis, a first peak belonging to the phenylhexanoate moiety was observed at a retention time of 10.44 min, and a second peak belonging to the oleate moiety was observed at a retention time of 13.06 min.

[0431] Preparation Example 4:

[0432] Semiconductor nanoparticles were fabricated in the same manner as in Preparation Example 1, except that 9-decenoic acid (9DeA) (9-decenoic acid, CAS No. 14436-32-9, manufactured by Sigma Aldrich) with the following chemical formula was used instead of 4-phenylbutyric acid.

[0433]

[0434] Photoluminescence spectroscopy and TGA were performed on the obtained semiconductor nanoparticles, and the results are summarized in Table 1.

[0435] GC analysis was performed on the obtained semiconductor nanoparticles, and the results are summarized in Table 2.

[0436] Comparative preparation example 1:

[0437] Semiconductor nanoparticles were prepared in the same manner as in Preparation Example 1, except that 4-phenylbutyric acid (the first compound) was not used.

[0438] Photoluminescence spectroscopy and TGA were performed on the obtained semiconductor nanoparticles, and the results are summarized in Table 1.

[0439] GC analysis was performed on the obtained semiconductor nanoparticles, and the results are summarized in Table 2.

[0440] Comparative preparation example 2:

[0441] Semiconductor nanoparticles were fabricated in the same manner as in Preparation Example 1, except that benzoic acid (BzA) (CAS No. 65-85-0, manufactured by Sigma Aldrich) with the following chemical formula was used instead of 4-phenylbutyric acid:

[0442]

[0443] Photoluminescence spectroscopy and TGA were performed on the obtained semiconductor nanoparticles, and the results are summarized in Table 1.

[0444] GC analysis was performed on the obtained semiconductor nanoparticles, and the results are summarized in Table 2.

[0445] Comparative preparation example 3-1:

[0446] [1] Semiconductor nanoparticles were obtained in the same manner as in Preparation Example 1, except that 4-phenylbutyric acid was not used.

[0447] [2] Surface ligand exchange (LE)

[0448] The semiconductor nanoparticles obtained above were dispersed in an organic solvent to obtain an organic dispersion of semiconductor nanocrystals. A solution containing benzoic acid (concentration: 10 wt%) was added to the prepared organic dispersion of semiconductor nanocrystals, and a surface exchange reaction was carried out by stirring at 60 °C for 30 minutes. After the reaction, ethanol was added to induce precipitation, and the semiconductor nanocrystals were recovered by centrifugation. The recovered semiconductor nanocrystals were subjected to the same surface exchange reaction again to obtain semiconductor nanocrystals (semiconductor nanoparticles) with surface exchange involving chlorides and benzoates.

[0449] Photoluminescence spectroscopy and TGA were performed on the obtained semiconductor nanoparticles, and the results are summarized in Table 1.

[0450] GC-MS analysis was performed on the obtained semiconductor nanoparticles. It was confirmed that the molar ratio of the benzoic acid-derived compound to the oleic acid-derived compound in the obtained semiconductor nanoparticles was greater than approximately 3.2:1.

[0451] Comparative preparation example 3-2:

[0452] Zinc chloride was dissolved in ethanol to prepare a zinc chloride solution with a concentration of 10 wt%. The zinc chloride solution was added to an organic dispersion of previously prepared semiconductor nanocrystals, and a surface exchange reaction was initiated by stirring at 60 °C for 30 minutes. After the reaction, ethanol was added to induce precipitation, and the semiconductor nanocrystals were recovered by centrifugation. The recovered semiconductor nanocrystals were subjected to the same surface exchange reaction again to obtain chloride-treated semiconductor nanocrystals.

[0453] Subsequently, the chloride-treated semiconductor nanocrystals were dispersed in toluene to obtain an organic dispersion of the semiconductor nanocrystals.

[0454] A solution containing benzoic acid (concentration: 10 wt%) was added to the prepared organic dispersion of semiconductor nanocrystals, and a surface exchange reaction was carried out by stirring at 60 °C for 30 minutes. After the reaction, ethanol was added to induce precipitation, and the semiconductor nanocrystals were recovered by centrifugation. The recovered semiconductor nanocrystals were subjected to the same surface exchange reaction again to obtain semiconductor nanocrystals (semiconductor nanoparticles) with surface exchange involving chlorides and benzoates.

[0455] It has been confirmed that the molar ratio of the benzoic acid-derived compound to the oleic acid-derived compound in the obtained semiconductor nanoparticles is greater than 3.2:1 (e.g., greater than or equal to about 4:1).

[0456] Table 1

[0457] PWL: Peak emission wavelength

[0458] FWHM: Full Width at Half Peak

[0459] QY: Absolute quantum yield

[0460] According to Table 1, compared to Comparative Preparation Example 1, the example semiconductor nanoparticles exhibit the desired dispersibility while showing a lower organic content. According to Table 1, it is confirmed that the example semiconductor nanoparticles exhibit quantum efficiencies comparable to or higher than those of Comparative Preparation Example 1 and Comparative Preparation Example 2. It is confirmed that, compared to Comparative Preparation Example 1, the ligand-exchanged semiconductor nanoparticles of Comparative Preparation Example 3 exhibit significantly reduced luminescence properties.

[0461] Table 2

[0462] The molar ratio of the first compound to the second compound was calculated based on the organic matter content obtained from TGA, the area ratio (weight ratio) of the chromatograms obtained from GC-MS results, and the molecular weight (g / mol) of the first and second compounds.

[0463] Experimental Example 1

[0464] Using HSPiP (Hansen Solubility Parameters in Practice), Hansen solubility parameters (i.e., dispersion solubility parameters, polar solubility parameters, and hydrogen bond parameters) were obtained for the fraction from the first compound (phenylhexanoic acid) with the COO group removed (hereinafter referred to as the first fraction) and for the fraction from the second compound (oleic acid) with the COO group removed (hereinafter referred to as the second fraction).

[0465] For the predetermined solvent (cyclohexylbenzene), the Hansen solubility parameter was also calculated using HSPiP. The Hansen solubility parameter distance between the portions of the first and second compounds (excluding the COO group) and cyclohexylbenzene was calculated while changing the molar fraction of the first portion relative to the total amount of the first and second portions to 0%, 20%, 40%, 60%, 80%, and 100%. The results are shown in... Figure 9A middle.

[0466] Hansen solubility parameters were obtained for a mixed solvent comprising cyclohexylbenzene, hexadecane, and octylbenzene. The distances between the Hansen solubility parameters of the first and second compounds (excluding the COO group) and the mixed solvent were calculated while changing the molar fraction of the first portion relative to the total amount of the first and second portions to 0%, 20%, 40%, 60%, 80%, and 100%. The results are shown in... Figure 9Bmiddle.

[0467] from Figure 9A and Figure 9B It has been confirmed that the Hansen solubility parameter distance (Ra) between the first and second parts (or the semiconductor nanoparticles containing them) and the solvent can be controlled to be less than about 4.

[0468] Device Examples

[0469] Example 1

[0470] An electroluminescent device with the structure ITO / PEDOT:PSS (300 Å) / TFB (250 Å) / semiconductor nanoparticle emission layer (360 Å) / ZnMgO (240 Å) / Al was fabricated using the semiconductor nanoparticles prepared in Preparation Example 1, and its electroluminescent properties were measured as follows:

[0471] On a glass substrate with an ITO electrode (first electrode) deposited thereon, a PEDOT:PSS layer and a TFB layer are formed by spin coating as a hole injection layer and a hole transport layer, respectively. On the formed TFB layer (25 nm), a semiconductor nanoparticle solution prepared in Example 1 is spin-coated to form an emission layer. On the emission layer, a zinc oxide magnesium nanoparticle layer is formed as an electron-assisted layer, and then an Al electrode is deposited to fabricate an electroluminescent device.

[0472] The electroluminescence properties and lifetime of the manufactured devices were measured. The lifetime characteristics are summarized in Table 3.

[0473] Example 2

[0474] The electroluminescent device was fabricated in the same manner as in Example 1, except that the semiconductor nanoparticles used in Preparation Example 2 were used. The electroluminescent properties and lifetime of the fabricated device were measured. The lifetime characteristics are summarized in Table 3 below.

[0475] Example 3

[0476] The electroluminescent device was fabricated in the same manner as in Example 1, except that the semiconductor nanoparticles fabricated in Preparation Example 3 were used. The electroluminescent properties and lifetime of the fabricated device were measured. The lifetime characteristics are summarized in Table 3 below.

[0477] Example 4

[0478] The electroluminescent device was fabricated in the same manner as in Example 1, except that the semiconductor nanoparticles fabricated in Preparation Example 4 were used. The electroluminescent properties and lifetime of the fabricated device were measured. The lifetime characteristics are summarized in Table 3 below.

[0479] Comparison Example 1

[0480] Electroluminescent devices were fabricated in the same manner as in Example 1, except that the semiconductor nanoparticles used in Comparative Fabrication Example 1 were employed. The electroluminescent properties and lifetime of the fabricated devices were measured. The lifetime characteristics are summarized in Table 3 below.

[0481] Comparison Example 2

[0482] Electroluminescent devices were fabricated in the same manner as in Example 1, except that the semiconductor nanoparticles fabricated in Comparative Fabrication Example 2 were used. The electroluminescent properties and lifetime of the fabricated devices were measured. The lifetime characteristics are summarized in Table 3 below.

[0483] Compare Example 3-1

[0484] Electroluminescent devices were fabricated in the same manner as in Example 1, except that the semiconductor nanoparticles fabricated in Comparative Fabrication Example 3-1 were used. The electroluminescent properties and lifetime of the fabricated devices were measured. The lifetime characteristics are summarized in Table 3 below.

[0485] Compare Example 3-2

[0486] Electroluminescent devices were fabricated in the same manner as in Example 1, except that the semiconductor nanoparticles fabricated in Comparative Fabrication Example 3-2 were used. The electroluminescent properties and lifetime of the fabricated devices were measured. The lifetime characteristics are summarized in Table 3 below.

[0487] Table 3

[0488] Relative T90: T90 (in hours) of a device operating at an initial brightness of 146 nits / T90 of the device in Comparative Example 1.

[0489] The results in Tables 1 and 3 confirm that, compared with the devices in the comparative examples, the example electroluminescent devices exhibit improved electroluminescent properties and extended lifetime.

[0490] Regarding the electroluminescence properties, it was confirmed that the devices of Examples 1 to 3 exhibited similar, equivalent, or higher electroluminescence performance (EQE and brightness) compared to the device of Comparative Example 1. It was confirmed that the device of Comparative Example 2 exhibited significantly lower EQE and brightness compared to the device of Comparative Example 1, even though the semiconductor nanoparticles prepared in Comparative Preparation Example 2 exhibited essentially the same QY as the semiconductor nanoparticles prepared in Comparative Preparation Example 1.

[0491] Experimental Example 2 (Hole device only, HOD fabrication)

[0492] Except for using a small-molecule organic hole transport material (e.g., LG101 (from LG Chem)) to form a hole-assisted layer instead of an electron transport layer, and setting the thickness of the semiconductor nanoparticle emitter layer to 40 nm, HOD 1, HOD 3, and HOD 4 (reference) were fabricated in the same manner as Examples 1, 3, and Comparative Example 1. Voltages ranging from 0 V to 8 V were applied three times to the fabricated devices, and hole transport capability (current density at 5 V during the third scan, in mA / cm²) was measured. The results are summarized in... Figure 10 middle.

[0493] It has been confirmed that, compared with HOD 4 (reference) which includes semiconductor nanoparticles from preparation example 1, HOD 1 which includes semiconductor nanoparticles from preparation example 1 and HOD 3 which includes semiconductor nanoparticles from preparation example 3 exhibit significantly improved hole transport properties.

[0494] Experimental Example 3

[0495] Semiconductor nanoparticles obtained from Comparative Preparation Example 1 were dispersed in cyclohexylbenzene to prepare an ink composition. An emission layer was formed in the same manner as in Example 1, except that the obtained ink composition was used. It was confirmed that significant aggregation occurred in the formed emission layer.

[0496] Semiconductor nanoparticles obtained from Comparative Preparation Examples 3-2 were dispersed in cyclohexylbenzene to prepare an ink composition. An emission layer was formed in the same manner as in Example 1, except that the obtained ink composition was used. It was confirmed that the emission layer was formed without substantial aggregation.

[0497] While this disclosure has been described in conjunction with what is now considered to be actual embodiments, it will be understood that the invention is not limited to the disclosed embodiments. Rather, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims

1. A semiconductor nanoparticle, in, The semiconductor nanoparticles are configured to emit light in response to external stimuli. The semiconductor nanoparticles include: semiconductor nanocrystals comprising zinc and selenium; and a semiconductor nanocrystal layer comprising zinc and sulfur, and wherein, on the semiconductor nanocrystals, The semiconductor nanoparticles further include a first compound and a second compound. The first compound includes a first functional group and an aromatic hydrocarbon group or an aliphatic hydrocarbon group, wherein the aliphatic hydrocarbon group has a terminal double bond. The second compound includes a second functional group and an aliphatic hydrocarbon group. The first and second functional groups each independently include a carboxylic acid or a carboxylic acid anion. In the gas chromatography-mass spectrometry (GC-MS) of the semiconductor nanoparticles, the first compound and the second compound exhibit a first peak and a second peak, respectively. The retention time of the second peak is longer than that of the first peak, and The ratio of the area of ​​the first peak to the area of ​​the second peak is greater than or equal to 0.1:1 and less than or equal to 3:

1.

2. The semiconductor nanoparticles according to claim 1, wherein, Semiconductor nanocrystals include zinc selenide, zinc telluride selenide, or combinations thereof.

3. The semiconductor nanoparticles according to claim 1, wherein, The molecular weight of the second compound is greater than that of the first compound.

4. The semiconductor nanoparticles according to claim 1, wherein, The first compound has a molecular weight greater than or equal to 150 g / mol and less than or equal to 500 g / mol, and The second compound has a molecular weight greater than or equal to 180 g per mole and less than or equal to 600 g per mole.

5. The semiconductor nanoparticles according to claim 1, wherein, The difference in molecular weight between the first compound and the second compound is greater than or equal to 90 g per mole and less than or equal to 150 g per mole.

6. The semiconductor nanoparticles according to claim 1, wherein, The first compound has a molecular weight greater than or equal to 165 g / mol and less than or equal to 400 g / mol, and The second compound has a molecular weight greater than or equal to 260 g per mole and less than or equal to 550 g per mole.

7. The semiconductor nanoparticles according to claim 1, wherein, The first compound further includes a linking group that connects the first functional group and the aromatic hydrocarbon group, and Linking groups include substituted or unsubstituted hydrocarbon groups having 3 or more and 19 or fewer carbon atoms.

8. The semiconductor nanoparticles according to claim 1, wherein, The first compound includes substituted or unsubstituted phenylhexanoic acid, substituted or unsubstituted phenylhexanoate, substituted or unsubstituted phenylvaleric acid, substituted or unsubstituted phenylvaleric acid, substituted or unsubstituted phenylbutyric acid, substituted or unsubstituted phenylbutyrate, substituted or unsubstituted phenylisopropionic acid, substituted or unsubstituted phenylisopropionic acid, substituted or unsubstituted phenylpropionic acid, substituted or unsubstituted phenylpropionic acid, substituted or unsubstituted phenylpropionic acid, substituted or unsubstituted 9-decenoic acid, substituted or unsubstituted 9-decenoate, substituted or unsubstituted 10-undecenoic acid, substituted or unsubstituted 10-undecenoate, substituted or unsubstituted 11-dodecenoic acid, substituted or unsubstituted 11-dodecenoate, or combinations thereof. The second compound includes: oleic acid, oleate, myristic acid, myristic acid salt, stearic acid, stearate, lauric acid, laurate, or combinations thereof.

9. The semiconductor nanoparticles according to claim 1, wherein, In the gas chromatography-mass spectrometry of the semiconductor nanoparticles, the ratio of the area of ​​the first peak to the area of ​​the second peak is greater than or equal to 0.5:1 and less than or equal to 1.45:

1.

10. The semiconductor nanoparticles according to claim 1, wherein, The semiconductor nanoparticles have an organic content of greater than or equal to 9.5% by weight and less than or equal to 13% by weight, as determined by thermogravimetric analysis.

11. The semiconductor nanoparticles according to claim 1, wherein, The semiconductor nanoparticles have an absolute quantum yield of greater than or equal to 80%, and The semiconductor nanoparticles have a chlorine content of less than or equal to 10% based on the total molar number of sulfur.

12. An ink composition comprising: The semiconductor nanoparticles according to claim 1; And solvents, In the semiconductor nanoparticles, the Hansen solubility parameter Ra of the first and second compounds relative to the solvent is greater than 0 and less than 4, and Ra satisfies the following equation: Ra²=4(δD1-δD2)²+(δP1-δP2)²+(δH1-δH2)² Ra: Hansen solubility parameter distance δD1: Dispersion solubility parameter of the first and second compounds excluding the COO group. δD2: Dispersion and solubility parameter of the solvent δP1: Polar solubility parameter of the first and second compounds excluding the COO group. δP2: Polar solubility parameter of the solvent δH1: Hydrogen bond parameter of the first and second compounds excluding the COO group. δH2: Hydrogen bonding parameter of the solvent.

13. The ink composition according to claim 12, wherein, The solvent is a substituted or unsubstituted C5 to C40 alicyclic hydrocarbon solvent, a substituted or unsubstituted C5 to C40 aliphatic hydrocarbon solvent, a substituted or unsubstituted C5 to C40 alicyclic hydrocarbon solvent, a substituted or unsubstituted C6 to C50 aromatic hydrocarbon solvent, a substituted or unsubstituted C5 to C40 aliphatic ester solvent, or a combination thereof. Optionally, the solvent has a boiling point greater than or equal to 200°C and less than or equal to 350°C.

14. A method for manufacturing semiconductor nanoparticles according to claim 1, the method comprising: Preparation of semiconductor nanocrystals; as well as A reaction medium comprising semiconductor nanocrystals, zinc precursor, sulfur precursor, a first compound, and a second compound in an organic solvent is heated to form a semiconductor nanocrystal layer on the semiconductor nanocrystals.

15. The method according to claim 14, wherein, The steps for forming a semiconductor nanocrystal layer include: A first medium comprising semiconductor nanocrystals, a zinc precursor, a sulfur precursor, and a second compound is reacted at a reaction temperature; and The first compound is added to the first medium.

16. The method of claim 14, wherein, The first compound includes substituted or unsubstituted phenylhexanoic acid, substituted or unsubstituted phenylhexanoate, substituted or unsubstituted phenylvaleric acid, substituted or unsubstituted phenylvaleric acid, substituted or unsubstituted phenylbutyric acid, substituted or unsubstituted phenylbutyrate, substituted or unsubstituted phenylisopropionic acid, substituted or unsubstituted phenylisopropionic acid, substituted or unsubstituted phenylpropionic acid, substituted or unsubstituted phenylpropionic acid, substituted or unsubstituted phenylpropionic acid, substituted or unsubstituted 9-decenoic acid, substituted or unsubstituted 9-decenoate, substituted or unsubstituted 10-undecenoic acid, substituted or unsubstituted 10-undecenoate, substituted or unsubstituted 11-dodecenoic acid, substituted or unsubstituted 11-dodecenoate, or combinations thereof. The second compound includes oleic acid, oleate, myristic acid, myristic acid salt, stearic acid, stearate, lauric acid, laurate, or combinations thereof.

17. The method according to claim 15, in, The step of adding the first compound is performed at a temperature greater than or equal to 180°C and less than the reaction temperature; or The second compound is included in the zinc precursor, and the molar ratio of the first compound to the zinc precursor is greater than or equal to 0.1:1 and less than or equal to 5:

1.

18. An electroluminescent device, in, The electroluminescent device includes a hole transport layer, an electron transport layer, and an emitting layer disposed between the hole transport layer and the electron transport layer. The emitter layer includes semiconductor nanoparticles according to claim 1.

19. The electroluminescent device according to claim 18, in, The hole transport layer includes poly(9,9-dioctylfluorene-co-N-(4-butylphenyl)diphenylamine), polyarylamine, poly(N-vinylcarbazole), poly(3,4-ethylenedioxythiophene): polystyrene sulfonate, polyaniline, polypyrrole, fluorene arylamine compounds, N,N,N',N'-tetra(4-methoxyphenyl)benzidine, 4,4'-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl, 4,4',4"-tris[phenyl(m-tolyl)amino]triphenylamine, 4,4',4"-tris(N-carbazolyl)-triphenylamine, 1,1-bis[di(4-tolyl)aminophenyl]cyclohexane, NiO, WO3, MoO3, graphene oxide, or combinations thereof, and The electron transport layer includes 1,4,5,8-naphthyl-tetracarboxylic dianhydride, copper bath, tris[3-(3-pyridyl)trimethylmethyl]borane, LiF, tris(8-hydroxyquinoline)aluminum, tris(8-hydroxyquinoline)gallium, tris(8-hydroxyquinoline)indium, bis(8-hydroxyquinoline)zinc, bis(2-(2-hydroxyphenyl)benzothiazole)zinc, bis(10-hydroxybenzo[h]quinoline)beryllium, 8-(4-(4,6-di(naphthyl-2-yl)-1,3,5-triazin-2-yl)phenyl)quinolone, lithium 8-hydroxyquinoline, zinc oxide nanoparticles, n-type doped zinc metal oxide nanoparticles, hafnium oxide nanoparticles, or combinations thereof.

20. The electroluminescent device according to claim 18, in, Semiconductor nanoparticles have a chlorine content of less than or equal to 10% based on the total molar number of sulfur.

21. A display device comprising semiconductor nanoparticles according to claim 1.

22. The display device according to claim 21, wherein, The display device is configured to be included in a virtual reality display device, an augmented reality display device, a wearable device, a portable terminal device, a monitor, a computer, a sensor, a television set, an electronic display panel, a camera, or an automotive electronic component.

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