Semiconductor nanoparticles and electronic devices containing semiconductor nanoparticles

Abstract

The present application provides semiconductor nanoparticles, thin films containing the semiconductor nanoparticles, and electronic devices including the thin films, wherein the semiconductor nanoparticles include: a cluster composed of a first semiconductor compound; a core covering at least a portion of the surface of the cluster and containing a second semiconductor compound; and a shell covering at least a portion of the surface of the core and containing a third semiconductor compound, wherein the first semiconductor compound and the third semiconductor compound each contain zinc (Zn), the second semiconductor compound contains Zn, tellurium (Te) and selenium (Se), the first semiconductor compound and the second semiconductor compound are different from each other, and the second semiconductor compound and the third semiconductor compound are different from each other.

Description

Technical Field

[0001] Semiconductor nanoparticles and electronic devices including the semiconductor nanoparticles are provided. Background Art

[0002] Semiconductor nanoparticles, which are crystalline materials having a nanoscale size of several nanometers, exhibit a quantum confinement effect and are also called quantum dots.

[0003] Semiconductor nanoparticles receive light from an excitation source and thus enter an excited state, and then emit energy corresponding to the energy band gap. Semiconductor nanoparticles exhibit characteristics such as excellent color purity and high luminous efficiency, and therefore, can be used in various applications. Specifically, semiconductor nanoparticles can be used in lighting equipment, display equipment, etc. Summary of the invention

[0004] Technical issues

[0005] Semiconductor nanoparticles and electronic devices containing the semiconductor nanoparticles are provided. Specifically, cadmium-free semiconductor nanoparticles and electronic devices containing the cadmium-free semiconductor nanoparticles are provided.

[0006] Solution to the problem

[0007] According to one aspect, a semiconductor nanoparticle is provided, comprising: a cluster composed of a first semiconductor compound; a core covering at least a portion of a surface of the cluster and containing a second semiconductor compound; and a shell covering at least a portion of a surface of the core and containing a third semiconductor compound, wherein the first semiconductor compound and the third semiconductor compound each contain zinc (Zn), the second semiconductor compound contains Zn, tellurium (Te) and selenium (Se), the first semiconductor compound and the second semiconductor compound are different from each other, and the second semiconductor compound and the third semiconductor compound are different from each other.

[0008] In an embodiment, the first semiconductor compound may include ZnSe.

[0009] In an embodiment, the second semiconductor compound may be ZnSe 1-x Te x Indicates that x can satisfy 0.05 <x≤0.5。

[0010] In an embodiment, x may satisfy 0.33≤x≤0.5.

[0011] In an embodiment, the third semiconductor compound may include ZnSe or ZnSe y S 1-y, where y can satisfy 0≤y<1.

[0012] In an embodiment, a band gap of the first semiconductor compound may be greater than a band gap of the second semiconductor compound, and a band gap of the third semiconductor compound may be greater than a band gap of the second semiconductor compound.

[0013] In embodiments, the semiconductor nanoparticles may have spherical quantum wells.

[0014] In embodiments, the semiconductor nanoparticles may emit light having a maximum emission wavelength of about 445 nm to about 550 nm.

[0015] In an embodiment, the semiconductor nanoparticle may further include an outer shell covering at least a portion of a surface of the shell and including a fourth semiconductor compound, wherein the fourth semiconductor compound may include a Group II element.

[0016] In an embodiment, the fourth semiconductor compound may include Zn, and may be a binary compound or a ternary compound.

[0017] In an embodiment, the fourth semiconductor compound may include ZnS, ZnSe, ZnTe, ZnO, ZnSeS, ZnSeTe, ZnSTe, or any combination thereof.

[0018] In embodiments, the semiconductor nanoparticles may emit light having a maximum emission wavelength of about 470 nm to about 650 nm.

[0019] In embodiments, the clusters may have an average diameter of less than or equal to about 1.5 nm.

[0020] In embodiments, the core may have an average diameter of about 2 nm to about 5 nm.

[0021] In embodiments, the semiconductor nanoparticles may have an average diameter of about 3 nm to about 13 nm.

[0022] According to another aspect, an electronic device is provided, comprising: a first substrate; a light emitting device; and a second substrate, wherein the second substrate may contain the semiconductor nanoparticles.

[0023] In an embodiment, the semiconductor nanoparticles may be contained in a region of the second substrate and may absorb blue light and emit visible light.

[0024] In an embodiment, the second substrate may further include another region different from the one region, and the another region may not include the semiconductor nanoparticles but include scatterers.

[0025] In an embodiment, the second substrate may be positioned in a direction of travel of light emitted by the light emitting device.

[0026] According to another aspect, an electronic device is provided, the electronic device including: a first electrode; a second electrode; and an intermediate layer disposed between the first electrode and the second electrode, wherein the intermediate layer may contain the semiconductor nanoparticles.

[0027] The beneficial effects of public content

[0028] In the semiconductor nanoparticles, the lattice mismatch between the core and the shell can be reduced, thereby improving the luminous efficiency. In addition, the semiconductor nanoparticles can have a larger diameter because they are prepared by using clusters. Therefore, the electronic device containing the semiconductor nanoparticles can have improved efficiency and improved color purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic diagram of a semiconductor nanoparticle according to an embodiment.

[0030] Figure 2 yes Figure 1 A partial enlarged view of .

[0031] Figure 3 is a schematic diagram of a semiconductor nanoparticle according to another embodiment.

[0032] Figure 4 yes Figure 3 A partial enlarged view of .

[0033] Figure 5 It is a graph showing the UV-Vis absorption spectra of Examples and Comparative Examples.

[0034] Figure 6 It is a graph showing the photoluminescence (PL) spectra of Examples and Comparative Examples.

[0035] Figure 7 It is a graph showing the PL quantum yield (QY) of Examples and Comparative Examples.

[0036] Figure 8 It is a graph showing the time-dependent PLQY of Examples and Comparative Examples.

[0037] Fig. 9 is a TEM image of Example 1, and Fig.10 This is a TEM image of Example 2.

[0038] Fig.11 and Fig.12 Each is a schematic cross-sectional view of a structure of an electronic device according to an embodiment. DETAILED DESCRIPTION

[0039] Since the present disclosure can have multiple modified embodiments, the embodiments are illustrated in the drawings and described in the detailed description. When referring to the embodiments described with reference to the drawings, the effects and characteristics of the present disclosure and the methods for achieving these will be apparent. However, the present disclosure can be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein.

[0040] It should be understood that although the terms "first", "second", etc. used herein may be used herein to describe various components, these components should not be limited by these terms. These components are only used to distinguish one component from another.

[0041] An expression used in the singular includes the expression in the plural unless it has an obviously different meaning in the context.

[0042] In the specification, it should be understood that terms such as "include", "have" and "include" are intended to indicate the presence of features or components disclosed in the specification, and are not intended to exclude the possibility that one or more other features or components may exist or may be added. For example, unless otherwise defined, terms such as "include" or "have" may mean consisting of only the features or components described in the specification or further including other components.

[0043] The same reference numerals in the drawings denote the same components, and the size of each component in the drawings may be exaggerated or reduced for clarity and convenience of description.

[0044] When a part of a layer, film, region, plate, etc. is referred to as being "on" another part, this includes not only the case where the part is "directly on" another part, but also the case where an intervening layer is placed therebetween. When a part is placed "directly" on another part, this means that there are no intervening layers.

[0045] The term "maximum emission wavelength" used herein refers to a wavelength value corresponding to a point having a maximum emission intensity in a photoluminescence (PL) spectrum of a solution or a film sample containing a compound.

[0046] The term “full width at half maximum (FWHM)” used herein refers to the wavelength width at a point corresponding to 1 / 2 of the maximum emission intensity in the above-described PL spectrum.

[0047] The term "Group" as used herein refers to a Group as on the IUPAC Periodic Table of the Elements.

[0048] The term "average diameter" used herein refers to the average value of diameters measured from all semiconductor nanoparticles included in any sample.

[0049] The term "average thickness" used herein refers to the average value of thicknesses measured from all semiconductor nanoparticles included in any sample.

[0050] In the following, reference will be made to Figure 1 and Figure 2 The semiconductor nanoparticle 1 according to the embodiment is described.

[0051] Semiconductor nanoparticle 1 includes cluster 110 composed of a first semiconductor compound, core 120 covering at least a portion of a surface of cluster 110 and containing a second semiconductor compound, and shell 130 covering at least a portion of a surface of core 120 and containing a third semiconductor compound.

[0052] When the core 120 included in the semiconductor nanoparticle 1 grows to cover at least a portion of the surface of the cluster 110, the lattice of the second semiconductor compound may be formed into the lattice shape of the first semiconductor compound. Then, the shell 130 may be formed to cover at least a portion of the surface of the core 120, and thus, the lattice mismatch between the core 120 and the shell 130 may be reduced. Therefore, the semiconductor nanoparticle 1 may have improved luminous efficiency.

[0053] The first semiconductor compound may include zinc (Zn).

[0054] In an embodiment, the semiconductor nanoparticle 1 may not include a heavy metal such as cadmium (Cd). Although the semiconductor nanoparticle 1 does not include a heavy metal such as Cd, the semiconductor nanoparticle 1 may have a spherical quantum well (SQW) structure by using Zn.

[0055] In an embodiment, the first semiconductor compound may include Zn and one or more than one selected from Group VI elements.

[0056] In one or more embodiments, the first semiconductor compound may include Zn and one or more selected from sulfur (S), selenium (Se), and tellurium (Te).

[0057] In an embodiment, the first semiconductor compound may be ZnSe.

[0058] In an embodiment, clusters 110 may have an average diameter R of less than or equal to about 1.5 nm. 1 In one or more embodiments, clusters 110 may have an average diameter R of less than or equal to about 1.4 nm. 1Since the average diameter R of the cluster 110 1 The average diameter R of the cluster 110 is less than or equal to about 1.5 nm, so the cluster 110 is distinguished from the core generally referred to in the art. In addition, since the average diameter R of the cluster 110 is 1 Less than or equal to about 1.5 nm, and thus the cluster 110 may not satisfy a band gap suitable for light emission. Typically, the core or the like may have a diameter of about 2 nm to about 7 nm.

[0059] The second semiconductor compound may contain Zn, Te, and Se.

[0060] In an embodiment, the second semiconductor compound may be composed of ZnSe 1-x Te x Indicates that x can satisfy 0.05 <x≤0.5。

[0061] Here, x refers to ZnSe contained in the core 120 of the semiconductor nanoparticle 1. 1-x Te x The composition ratio of Te to Zn. In an embodiment, when x satisfies the range of greater than 0.05 and less than or equal to 0.5, the semiconductor nanoparticles 1 may emit visible light, for example, blue visible light or green visible light. In one or more embodiments, when x is less than or equal to 0.05, the proportion of Te in the core 120 of the semiconductor nanoparticles 1 is reduced, so that the emission wavelength of the semiconductor nanoparticles 1 is shortened. Therefore, the semiconductor nanoparticles 1 may not emit visible light, or may emit purple visible light. In one or more embodiments, when x is less than or equal to 0.05, the film containing the semiconductor nanoparticles 1 may have a low absorbance for visible light, and therefore the electronic device coupled to the light-emitting device emitting visible light may have reduced efficiency.

[0062] For example, x may satisfy 0.33≤x≤0.5. When x satisfies 0.33≤x≤0.5, the semiconductor nanoparticle 1 may emit green light.

[0063] In an embodiment, the core 120 may include two or more types of second semiconductor compounds having different compositions. For example, the core 120 may include ZnSe 0.75 Te 0.25 、ZnSe 0.67 Te 0.33 、ZnSe 0.50 Te 0.50 or any combination thereof.

[0064] In an embodiment, the core 120 may have an average diameter R of about 2.0 nm to about 5.0 nm. 2, for example, greater than or equal to 2.5 nm, greater than or equal to 3 nm, greater than or equal to 3.2 nm, less than or equal to 4.5 nm, or less than or equal to 4 nm.

[0065] The third semiconductor compound may contain Zn.

[0066] In an embodiment, the third semiconductor compound may include Zn and one or more than one selected from Group VI elements.

[0067] In one or more than one embodiments, the third semiconductor compound may include Zn and one or more than one selected from S, Se and Te.

[0068] In an embodiment, the third semiconductor compound may include ZnSe or ZnSe y S 1-y , where y can satisfy 0≤y<1. Here, y refers to ZnSe y S 1-y When the third semiconductor compound includes ZnSe or ZnSe y S 1-y When the core 120 and the shell 130 are thick, the lattice mismatch between the core 120 and the shell 130 can be reduced, thereby minimizing the structural defects of the semiconductor nanoparticle 1. Therefore, the shell 130 can be formed to be sufficiently thick so as to improve the stability of the semiconductor nanoparticle 1.

[0069] For example, the third semiconductor compound may include ZnSe, ZnSeS, or ZnS.

[0070] In an embodiment, the shell 130 may have an average thickness D of 0.25 nm to 1.5 nm. 1 , and for example, the average thickness D of the shell 130 1 It may be greater than or equal to 0.3 nm, greater than or equal to 0.4 nm, greater than or equal to 0.5 nm, less than or equal to 1.3 nm, less than or equal to 1.2 nm, or less than or equal to 1.1 nm.

[0071] The shell 130 may function as a protective layer that prevents chemical denaturation of the core 120 to maintain semiconductor characteristics and / or as a charging layer that imparts electrophoretic characteristics to the semiconductor nanoparticle 1 .

[0072] The shell 130 may be composed of a single layer or a multilayer, and the interface between the core 120 and the shell 130 may have a concentration gradient in which the concentration of an element present in the shell 130 decreases toward the center.

[0073] The first semiconductor compound and the second semiconductor compound may be different from each other, and the second semiconductor compound and the third semiconductor compound may be different from each other.

[0074] In an embodiment, the first semiconductor compound and the third semiconductor compound may be the same as each other.

[0075] For example, the first semiconductor compound may be ZnSe, and the third semiconductor compound may also be ZnSe, but the embodiment is not limited thereto.

[0076] In an embodiment, the band gap of the cluster 110 may be larger than the band gap of the core 120 , and the band gap of the shell 130 may also be larger than the band gap of the core 120 .

[0077] For example, the band gap of the cluster 110 may be 3.7 eV to 3.72 eV, the band gap of the core 120 may be 2.4 eV to 2.95 eV, and the band gap of the shell 130 may be 2.82 eV to 3.2 eV, but the embodiment is not limited thereto. When the above-described conditions are met, a semiconductor nanoparticle 1 having improved efficiency and improved stability may be provided. Specifically, when the band gap meets the above range, a semiconductor nanoparticle 1 having a quasi-II type band structure but having improved efficiency and improved stability may be provided.

[0078] In an embodiment, the semiconductor nanoparticle 1 may have a SQW.

[0079] The semiconductor nanoparticles 1 can emit visible light. For example, the semiconductor nanoparticles 1 can emit light having a maximum emission wavelength of 445 nm to 550 nm. In an embodiment, the semiconductor nanoparticles 1 can emit light having a maximum emission wavelength of 480 nm to 540 nm. In one or more than one embodiment, the semiconductor nanoparticles 1 can emit light having a maximum emission wavelength of 530 nm to 540 nm. Therefore, when the semiconductor nanoparticles 1 are applied to a color conversion member, a blue or green color with high brightness and high color purity can be achieved.

[0080] In an embodiment, the semiconductor nanoparticles 1 may have an average diameter R of 3.0 nm to 13.0 nm. 2 +2D 1 For example, the average diameter R of the semiconductor nanoparticles 1 is 2 +2D 1 It may be greater than or equal to 4.0 nm, greater than or equal to 4.5 nm, greater than or equal to 5.0 nm, less than or equal to 7.0 nm, less than or equal to 6.5 nm, or less than or equal to 6.0 nm.

[0081] In an embodiment, the full width at half maximum (FWHM) of the emission wavelength spectrum of the semiconductor nanoparticles 1 may be less than or equal to 60 nm, for example, less than or equal to 55 nm or less than or equal to 40 nm. When the FWHM of the emission wavelength spectrum of the semiconductor nanoparticles 1 is within the above range, the semiconductor nanoparticles 1 may have high color purity, excellent color reproducibility, and a wide viewing angle.

[0082] In the embodiment, the semiconductor nanoparticle 1 can have a reduced lattice mismatch between the core 120 and the shell 130, and have a reduced generation of structural defects at the interface between the core 120 and the shell 130, so that the shell 120 can be formed to a sufficient thickness. In one or more embodiments, when the semiconductor nanoparticle 1 is prepared by using the cluster 110, the semiconductor nanoparticle 1 can be prepared to a relatively large size. In this regard, the semiconductor nanoparticle 1 according to the embodiment can achieve high efficiency and high color purity.

[0083] In one embodiment, the form of the semiconductor nanoparticles 1 is not particularly limited and can be any one commonly used in the art. For example, the semiconductor nanoparticles 1 can be spherical, pyramidal, multi-armed or cubic nanoparticles, nanotubes, nanowires, nanofibers or nanoplates.

[0084] In the embodiment, the semiconductor nanoparticle 1 may further include other compounds in addition to the composition described above.

[0085] For example, the semiconductor nanoparticle 1 may include a II-VI compound, a III-VI compound, a III-V compound, a IV-VI compound, a IV element or compound, a I-III-VI compound, or a combination thereof in the core 120 or the shell 130 .

[0086] For example, the II-VI compounds may include binary compounds selected from the group consisting of CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and mixtures thereof; ternary compounds selected from the group consisting of CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, Cd ZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS and mixtures thereof; a quaternary compound selected from CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe and mixtures thereof; or any combination thereof.

[0087] For example, the III-VI compound may include: a binary compound selected from In 2 S 3 、In 2 Se 3 and mixtures thereof; ternary compounds selected from InGaS 3 、InGaSe 3 and mixtures thereof; or any combination thereof.

[0088] For example, the III-V compound may include a binary compound selected from GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and mixtures thereof; a ternary compound selected from GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InAlP, InNP, InNAs, InNSb, InPAs, InPSb, and mixtures thereof; a quaternary compound selected from GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and mixtures thereof; or any combination thereof. The III-V semiconductor compound may further include a Group II metal (e.g., InZnP, etc.).

[0089] For example, the IV-VI group compounds may include: binary compounds, the binary compounds are selected from SnS, SnSe, SnTe, PbS, PbSe, PbTe and mixtures thereof; ternary compounds, the ternary compounds are selected from SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe and mixtures thereof; quaternary compounds, the quaternary compounds are selected from SnPbSSe, SnPbSeTe, SnPbSTe and mixtures thereof; or any combination thereof.

[0090] For example, the Group IV element or compound may include: a single element selected from Si, Ge, and a mixture thereof; a binary compound selected from SiC, SiGe, and a mixture thereof; or any combination thereof.

[0091] For example, the I-III-VI group compound may include: a ternary compound selected from AgInS, AgInS 2 、CuInS、CuInS 2 、CuGaO 2 、AgGaO 2 、AgAlO 2 and mixtures thereof; or any combination thereof.

[0092] The binary compound, ternary compound, or quaternary compound may be present in a particle at a uniform concentration, or may be present in the same particle in a state in which the concentration distribution is partially different.

[0093] In an embodiment, the shell 130 may further include a metal oxide, a non-metal oxide, or a combination thereof.

[0094] For example, metal oxides or non-metal oxides can be: binary compounds such as SiO 2 、Al 2 O 3 、TiO 2 、ZnO、MnO、Mn 2 O 3 , Mn 3 O 4 , CuO, FeO, Fe 2 O 3 , Fe 3 O 4 , CoO, Co 3 O 4 , NiO, etc.; or ternary compounds, such as MgAl 2 O 4 、CoFe 2 O 4 、NiFe2 O 4 、CoMn 2 O 4 wait.

[0095] In the following, reference will be made to Figure 3 and Figure 4 A semiconductor nanoparticle 2 according to another embodiment is described.

[0096] The semiconductor nanoparticle 2 may include: a cluster 210 composed of a first semiconductor compound; a core 220 covering at least a portion of the surface of the cluster 210 and containing a second semiconductor compound; a first shell 230 covering at least a portion of the surface of the core 220 and containing a third semiconductor compound; and a second shell 240 covering at least a portion of the surface of the first shell 230 and containing a fourth semiconductor compound. Here, the first shell 230 and the second shell 240 may be referred to as an inner shell and an outer shell, respectively. The description of the first semiconductor compound, the second semiconductor compound, and the third semiconductor compound contained in the semiconductor nanoparticle 2 may refer to the description of the first semiconductor compound, the second semiconductor compound, and the third semiconductor compound contained in the semiconductor nanoparticle 2. Figure 1 and Figure 2 Those described above, and may be respectively the same as the first semiconductor compound, the second semiconductor compound, and the third semiconductor compound contained in the semiconductor nanoparticle 1. Therefore, overlapping descriptions will be omitted.

[0097] The fourth semiconductor compound may include a Group II element.

[0098] In an embodiment, the fourth semiconductor compound may include Zn, and may be a binary compound or a ternary compound.

[0099] In one or more embodiments, the fourth semiconductor compound may include ZnS, ZnSe, ZnTe, ZnO, ZnSeS, ZnSeTe or ZnSTe.

[0100] In one or more embodiments, the first semiconductor compound may be ZnS.

[0101] In an embodiment, the shell 240 may have an average thickness D of 0.3 nm to 1.5 nm. 2 For example, the average thickness D of the housing 240 is 2 It may be greater than or equal to 0.4 nm, greater than or equal to 0.5 nm, less than or equal to 1.4 nm, less than or equal to 1.3 nm, less than or equal to 1.2 nm, or less than or equal to 1.1 nm.

[0102] The shell 240 may function as a protective layer that prevents chemical denaturation of the core 220 to maintain semiconductor properties and / or as a charging layer that imparts electrophoretic properties to the semiconductor nanoparticles 2 .

[0103] The outer shell 240 may be composed of a single layer or a plurality of layers, and an interface between the inner shell 230 and the outer shell 240 may have a concentration gradient in which the concentration of an element present in the outer shell 240 decreases toward the center.

[0104] The semiconductor nanoparticles 2 may emit visible light in addition to blue light. The semiconductor nanoparticles 2 may emit light having a maximum emission wavelength of 470 nm to 650 nm. In an embodiment, the semiconductor nanoparticles 2 may emit light having a maximum emission wavelength of 490 nm to 570 nm. Therefore, when the semiconductor nanoparticles 2 are applied to a color conversion member, a green color having high brightness and high color purity may be achieved.

[0105] In an embodiment, the semiconductor nanoparticles 2 may have an average diameter R of 3.0 nm to 13.0 nm. 2 +2D 1 +2D 2 For example, the average diameter R of the semiconductor nanoparticles 2 is 2 +2D 1 +2D 2 It may be greater than or equal to 4.0 nm, greater than or equal to 4.5 nm, greater than or equal to 5.0 nm, greater than or equal to 5.5 nm, greater than or equal to 6.0 nm, less than or equal to 10.0 nm, less than or equal to 9.5 nm, less than or equal to 9.0 nm, less than or equal to 8.5 nm, or less than or equal to 8.0 nm.

[0106] In an embodiment, the FWHM of the emission wavelength spectrum of the semiconductor nanoparticles 2 may be less than or equal to 60 nm, for example, less than or equal to 55 nm or less than or equal to 40 nm. When the FWHM of the emission wavelength spectrum of the semiconductor nanoparticles 2 is within the above range, the semiconductor nanoparticles 2 may have high color purity, excellent color reproducibility, and a wide viewing angle.

[0107] Hereinafter, an electronic device including the semiconductor nanoparticles described above will be described.

[0108] The electronic device may include a light emitting device including: semiconductor nanoparticles and a first electrode; a second electrode; and an intermediate layer disposed between the first electrode and the second electrode.

[0109] In an embodiment, the electronic device may include a liquid crystal display device, an organic light emitting display device, or an inorganic light emitting display device.

[0110] For example, when the electronic device further includes liquid crystal, the electronic device may be a liquid crystal display device. Here, a light emitting device may be used as a light source, and semiconductor nanoparticles may be contained outside the light emitting device and the liquid crystal to serve as a color conversion member.

[0111] In the embodiment, in the case where the intermediate layer of the light-emitting device includes an emission layer and the emission layer contains an organic material, the electronic device can be an organic light-emitting display device. Here, the light-emitting device can be used as a light source, and semiconductor nanoparticles can be contained outside the light-emitting device to serve as a color conversion member.

[0112] In one or more embodiments, in the case where the intermediate layer of the light emitting device includes an emission layer and the emission layer contains an inorganic material such as semiconductor nanoparticles, the electronic device may be an inorganic light emitting display device.

[0113] In addition to the light emitting device described above, the electronic device may further include a thin film transistor. The thin film transistor may include a source electrode, a drain electrode and an active layer, wherein any one of the source electrode and the drain electrode may be electrically connected to any one of the first electrode and the second electrode of the light emitting device.

[0114] The thin film transistor may further include a gate electrode, a gate insulating layer, and the like.

[0115] The active layer may include crystalline silicon, amorphous silicon, an organic semiconductor, an oxide semiconductor, or the like.

[0116] The electronic device may further include a sealing portion for sealing the light emitting device. The sealing portion allows light from the light emitting device to be led out to the outside, and at the same time prevents ambient air and moisture from penetrating into the light emitting device. The sealing portion may be a sealing substrate including a transparent glass substrate or a plastic substrate. The sealing portion may be a thin film encapsulation layer including at least one of an organic layer and an inorganic layer. When the sealing portion is a thin film encapsulation layer, the electronic device may be flexible.

[0117] Depending on the purpose of the electronic device, various functional layers may be additionally located on the seal. Examples of functional layers are color filters, color conversion layers, touch screen layers, and polarization layers. The touch screen layer may be a pressure-sensitive touch screen layer, a capacitive touch screen layer, or an infrared touch screen layer.

[0118] In the following, reference will be made to Fig.11 The electronic device 3 according to the embodiment is described in detail.

[0119] The electronic device 3 may include a first substrate 310 , a light emitting device 320 , and a second substrate 340 .

[0120] Semiconductor nanoparticles may be included outside the light emitting device 320 (ie, on the first electrode and / or the second electrode). Specifically, semiconductor nanoparticles may be included in the second substrate 340 located outside the light emitting device 320. The second substrate 340 may serve as a color conversion member, and the light emitting device 320 may serve as a light source.

[0121] The light emitting device 320 may include a first electrode 321 , a second electrode 323 , and an intermediate layer 322 disposed between the first electrode 321 and the second electrode 323 .

[0122] The electronic device 3 may be an organic light emitting display device. Therefore, the light emitting device 320 may include an organic emission layer in the intermediate layer 322 .

[0123] The pixel defining layer 330 may be disposed on the first electrode 321. The pixel defining layer 330 exposes a region of the first electrode 321, and the intermediate layer 322 may be disposed in the exposed region.

[0124] In an embodiment, region 341 of second substrate 340 may contain semiconductor nanoparticles. In this case, second substrate 340 may be positioned in a direction in which light emitted by light emitting device 320 travels.

[0125] Semiconductor nanoparticles can absorb blue light and emit visible light. Therefore, the second substrate 340 can be designed to absorb blue light and emit light with a wide color range wavelength. Therefore, the light emitting device 320 can emit blue light with a maximum emission wavelength of, for example, 400nm to 490nm, and the film can absorb blue light and emit visible light with a maximum emission wavelength of, for example, 445nm to 650nm.

[0126] In an embodiment, the second substrate 340 may further include a scatterer.

[0127] In an embodiment, the second substrate 340 may further include another region (not shown) different from the region 341, and the other region may not include semiconductor nanoparticles, and the other region may transmit blue light from the light emitting device 320. Specifically, only the region 341 may include semiconductor nanoparticles, and the other region may include only scatterers.

[0128] In an embodiment, the second substrate 340 may further include a light shielding pattern 344 between the region 341 and another region.

[0129] In the following, reference will be made to Fig.12 An electronic device 4 according to another embodiment is described in detail.

[0130] The electronic device 4 includes a first substrate 410 and a light emitting device 420 .

[0131] The light emitting device 420 includes a first electrode 421 , a second electrode 423 , and an intermediate layer 422 disposed between the first electrode 421 and the second electrode 423 .

[0132] Semiconductor nanoparticles may be included in the intermediate layer 422 , for example, in an emission layer in the intermediate layer 422 .

[0133] Semiconductor nanoparticles can emit visible light. Therefore, the light emitting device 420 can be designed to emit light having a wide color range wavelength. For example, semiconductor nanoparticles can emit visible light having a maximum emission wavelength of 445nm to 650nm.

[0134] The intermediate layer 422 may further include an auxiliary layer between the emission layer and the first electrode 421 and / or between the emission layer and the second electrode 423. The auxiliary layer may directly contact the emission layer. The auxiliary layer may improve the thin film characteristics of the emission layer.

[0135] The intermediate layer 422 may further include a first charge transfer region between the emission layer and the first electrode 421 and / or a second charge transfer region between the emission layer and the second electrode 423 .

[0136] Hereinafter, a method of preparing semiconductor nanoparticles will be described in detail.

[0137] The method for preparing semiconductor nanoparticles includes: forming a cluster composed of a first semiconductor compound, and then forming a core containing a second semiconductor compound to cover at least a portion of the surface of the cluster; and forming a shell containing a third semiconductor compound to cover at least a portion of the surface of the core.

[0138] The first semiconductor compound and the third semiconductor compound may each contain Zn, and the second semiconductor compound may contain Zn, Te, and Se. The first semiconductor compound and the second semiconductor compound may be different from each other, and the second semiconductor compound and the third semiconductor compound may be different from each other.

[0139] In an embodiment, the mixture of the precursor of the first semiconductor compound and the solvent may be allowed to react at a cluster forming temperature, such as 200° C. to 250° C., such as 230° C., to form clusters composed of the first semiconductor compound. The precursor of the first semiconductor compound mainly contains Zn.

[0140] The cluster thus formed does not undergo any separate separation process, and a Se precursor and / or a Te precursor can be directly added thereto to form a core including the second semiconductor compound.

[0141] Since the cluster thus formed does not undergo any separate separation process, a core covering at least a portion of the cluster can be formed just on top of the cluster after the cluster grows. Therefore, the core can grow along the lattice of the cluster. For example, when the cluster undergoes a separation process, a highly reactive Se precursor and / or a Te precursor can react with Zn to form a core that does not include the cluster, rather than a core that covers at least a portion of the cluster. That is, when the cluster contains Cd, due to the large difference in reactivity to Zn, a core may not be formed according to the method described above.

[0142] In contrast, after the Se precursor and / or the Te precursor are added to the clusters, the resulting mixture can be allowed to react at a temperature of 200° C. to 250° C., for example, at a temperature of 230° C. For example, after the Se precursor and / or the Te precursor are immediately added to the mixture of the precursor of the first semiconductor compound and the solvent, the reaction can be carried out for 30 minutes to form the core.

[0143] Next, a precursor of a third semiconductor compound may be added and reacted to form a shell. In an embodiment, the reaction temperature for forming the shell may be 280°C to 320°C, such as 300°C to 320°C, and the reaction time for forming the shell is 15 minutes.

[0144] In an embodiment, after the core is formed, a purification process and / or a separation process may be further performed or may be omitted.

[0145] In an embodiment, the solvent may be an organic solvent. For example, the solvent may be trioctylamine, oleylamine, 1-octadecene (ODE), and the like.

[0146] Regarding other details of the method of preparing semiconductor nanoparticles, those skilled in the art will understand with reference to embodiments to be described later.

[0147] Hereinafter, semiconductor nanoparticles according to embodiments will be described in more detail.

[0148] [Example]

[0149] Example 1: ZnSe / ZnSe 0.67 Te 0.33 Synthesis of ZnSe semiconductor nanoparticles

[0150] In a three-necked flask, 0.6 mmol of zinc oleate and 10 mL of ODE were added. 0.2 mmol of diphenylphosphine selenide was added thereto at 230° C., and then 0.1 mmol of trioctylphosphine telluride was immediately added. The mixture was allowed to react for 30 minutes.

[0151] Next, 1 mmol of zinc oleate and 1 mmol of trioctylphosphine selenide were added thereto, and then allowed to react at a temperature elevated to 300° C. for 15 minutes, thereby forming a zinc selenide shell and the semiconductor nanoparticles of Example 1.

[0152] The semiconductor nanoparticles of Example 1 include ZnSe clusters, ZnSe 0.67 Te 0.33 core and ZnSe shell. Fig. 9 A TEM image of the semiconductor nanoparticles of Example 1 is shown.

[0153] Example 2: ZnSe / ZnSe 0.67 Te 0.33 Synthesis of ZnSe / ZnS Semiconductor Nanoparticles

[0154] In a three-necked flask, 0.6 mmol of zinc oleate and 10 mL of ODE were added. 0.2 mmol of diphenylphosphine selenide was added thereto at 230° C., and then 0.1 mmol of trioctylphosphine telluride was immediately added. The mixture was allowed to react for 30 minutes.

[0155] Next, 1 mmol of zinc oleate and 1 mmol of trioctylphosphine selenide were added thereto, and then allowed to react at a temperature elevated to 300° C. for 15 minutes, thereby forming a zinc selenide shell.

[0156] Then, 2 mmol of zinc oleate and 2 mmol of trioctylphosphine sulfide were added thereto and reacted for 1 hour to form a zinc sulfide shell to obtain the semiconductor nanoparticles of Example 2.

[0157] The semiconductor nanoparticles of Example 2 include ZnSe clusters, ZnSe 0.67 Te 0.33 core, ZnSe shell and ZnS outer shell. Fig.10 A TEM image of the semiconductor nanoparticles of Example 2 is shown.

[0158] Comparative Example 1: ZnSe 0.67 Te 0.33 Synthesis of ZnSe semiconductor nanoparticles

[0159] In a three-necked flask, 0.6 mmol of zinc oleate, 0.2 mmol of diphenylphosphine selenide, 0.1 mmol of trioctylphosphine telluride, and 10 mL of ODE were added simultaneously and allowed to react at 230° C. for 30 minutes.

[0160] Next, 1 mmol of zinc oleate and 1 mmol of trioctylphosphine selenide were added thereto, and then allowed to react at a temperature elevated to 300° C. for 15 minutes, thereby forming a zinc selenide shell and the semiconductor nanoparticles of Comparative Example 1.

[0161] Comparative Example 2: ZnSe 0.67 Te 0.33 Synthesis of ZnSe / ZnS Semiconductor Nanoparticles

[0162] In a three-necked flask, 0.6 mmol of zinc oleate, 0.2 mmol of diphenylphosphine selenide, 0.1 mmol of trioctylphosphine telluride, and 10 mL of ODE were added simultaneously and allowed to react at 230° C. for 30 minutes.

[0163] Next, 1 mmol of zinc oleate and 1 mmol of trioctylphosphine selenide were added thereto, and then allowed to react at a temperature elevated to 300° C. for 15 minutes, thereby forming a zinc selenide shell.

[0164] Then, 2 mmol of zinc oleate and 2 mmol of trioctylphosphine sulfide were added thereto and reacted for 1 hour to form a zinc sulfide shell to obtain semiconductor nanoparticles of Comparative Example 2.

[0165] Comparative Example 3: ZnSe / ZnSe 0.67 Te 0.33 Synthesis of semiconductor nanoparticles

[0166] In a three-necked flask, 0.6 mmol of zinc oleate and 10 mL of ODE were added. 0.2 mmol of diphenylphosphine selenide was added thereto at 230° C., and then 0.1 mmol of trioctylphosphine telluride was immediately added. The mixture was allowed to react at 230° C. for 30 minutes to obtain semiconductor nanoparticles of Comparative Example 3.

[0167] Comparative Example 4: Synthesis of ZnSe semiconductor nanoparticles

[0168] In a three-necked flask, 0.6 mmol of zinc oleate and 10 mL of ODE were added. 0.2 mmol of diphenylphosphine selenide was added thereto at 230° C., and then 0.2 mmol of trioctylphosphine telluride was added. The mixture was allowed to react at a temperature raised to 300° C. for 15 minutes to obtain semiconductor nanoparticles of Comparative Example 4.

[0169] Evaluation Example 1

[0170] Each of the semiconductor nanoparticles of Examples 1 and 2 and Comparative Examples 1 to 4 was evaluated in terms of UV-Vis spectrum, PL spectrum, maximum emission wavelength, FWHM, and PLQY, and the results thereof are shown in Tables 1 and 2. Figures 5 to 8 Here, PLQY was measured by dispersing semiconductor nanoparticles in toluene and adjusting the absorbance at 450 nm to 0.1.

[0171] Table 1

[0172]

[0173] Referring to Table 1, it was confirmed that the semiconductor nanoparticles of Example 1 and Example 2 had narrow FWHM and excellent PLQY.

[0174] In addition, refer to Table 1 and Figure 6 , it was confirmed that, unlike the semiconductor nanoparticles of Example 1 and Example 2 emitting green light, the semiconductor nanoparticles of Comparative Examples 3 and 4 emitted visible light having a maximum emission wavelength of less than 500 nm.

[0175] refer to Figure 5 , it was confirmed that the semiconductor nanoparticles of Examples 1 and 2 had high absorbance for blue light compared with the semiconductor nanoparticles of Comparative Examples 3 and 4.

[0176] Refer to Table 1 and Figure 7 , it was confirmed that the semiconductor nanoparticles of Example 2 including clusters had significantly improved PLQY compared to the semiconductor nanoparticles of Comparative Example 2 not including clusters.

[0177] refer to Figure 8 , it was confirmed that the semiconductor nanoparticles of Example 2 including clusters had a significantly longer service life compared to the semiconductor nanoparticles of Comparative Example 2 not including clusters.

Claims

1. Semiconductor nanoparticles, including: a cluster consisting of a first semiconductor compound; covering at least a portion of the surface of the cluster and comprising a core of a second semiconductor compound; as well as a shell covering at least a portion of the surface of the core and comprising a third semiconductor compound, wherein the third semiconductor compound is ZnSe, The first semiconductor compound is ZnSe, The second semiconductor compound is ZnSe 1-x Te x indicates that, and x satisfies 0.33≤x≤0.

5.

2. The semiconductor nanoparticle of claim 1, wherein the band gap of the cluster is larger than the band gap of the core, and The band gap of the shell is larger than the band gap of the core. The semiconductor nanoparticle of claim 1 , wherein the semiconductor nanoparticle has a spherical quantum well. The semiconductor nanoparticle of claim 1 , wherein the semiconductor nanoparticle emits light having a maximum emission wavelength of 510 nm to 550 nm.

5. The semiconductor nanoparticle of claim 1, further comprising an outer shell covering at least a portion of a surface of the shell and comprising a fourth semiconductor compound, The fourth semiconductor compound includes a Group II element. 6 . The semiconductor nanoparticle of claim 5 , wherein the fourth semiconductor compound comprises Zn and is a binary compound or a ternary compound.

7. The semiconductor nanoparticle of claim 5, wherein the fourth semiconductor compound comprises ZnS, ZnSe, ZnTe, ZnO, ZnSeS, ZnSeTe, ZnSTe, or any combination thereof. 8 . The semiconductor nanoparticle of claim 5 , wherein the semiconductor nanoparticle emits light having a maximum emission wavelength of 490 nm to 570 nm.

9. The semiconductor nanoparticle of claim 1, wherein the average diameter of the clusters is less than or equal to 1.5 nm.

10. The semiconductor nanoparticle of claim 1, wherein the average diameter of the core is 2.0 nm to 5.0 nm. 11 . The semiconductor nanoparticles of claim 1 , wherein an average diameter of the semiconductor nanoparticles is 3.0 nm to 13.0 nm.

12. An electronic device comprising a first substrate, a light emitting device and a second substrate, The second substrate comprises the semiconductor nanoparticles according to any one of claims 1 to 11.

13. The electronic device of claim 12, wherein the semiconductor nanoparticles are contained in a region of the second substrate, and The semiconductor nanoparticles absorb blue light and emit visible light.

14. The electronic device of claim 13, wherein the second substrate further comprises another region different from the one region, and The other region contains scatterers but does not contain the semiconductor nanoparticles. 15 . The electronic device of claim 12 , wherein the second substrate is positioned in a direction in which light emitted from the light emitting device travels.

16. An electronic device comprising a first electrode, a second electrode, and an intermediate layer between the first electrode and the second electrode, The intermediate layer comprises the semiconductor nanoparticles according to any one of claims 1 to 11.

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