Metal oxide nanoparticles and their manufacturing method, and light-emitting device including metal oxide nanoparticles

Abstract

The metal oxide nanoparticles according to one embodiment include a compound represented by the following Chemical Formula 1, and an alkylamine ligand having 8 to 18 carbon atoms located on the surface of the compound. [Chemical formula 1] ZnMo In the above formula 1, M may be one of Ca, Zr, Al, Li, Mg, Ni, Y, W, Co, and Ga.

Description

[Technical Field]

[0001] The present disclosure relates to metal oxide nanoparticles, a method for producing the same, and a light-emitting device including the metal oxide nanoparticles. [Background technology]

[0002] The light-emitting device includes an anode, a cathode, and a light-emitting layer formed between them. Holes injected from the anode and electrons injected from the cathode combine in the light-emitting layer to generate excitons, which emit light as they fall from an excited state to a ground state.

[0003] The light emitting device can be driven at a low voltage, can be constructed in a lightweight and thin form, and has excellent properties such as viewing angle, contrast, and response speed, so its range of applications is expanding from personal portable devices to televisions. Summary of the Invention [Problem to be solved by the invention]

[0004] The embodiments are intended to provide metal oxide nanoparticles, a method for producing the same, and a light-emitting device including the metal oxide nanoparticles and having improved light-emitting properties. [Means for solving the problem]

[0005] According to one embodiment, the metal oxide nanoparticles include a compound represented by the following Chemical Formula 1 and an alkylamine ligand having 8 to 18 carbon atoms located on the surface of the compound:

[0006] [Chemical formula 1] ZnMo

[0007] In the above formula 1, M may be one of Ca, Zr, Al, Li, Mg, Ni, Y, W, Co, and Ga.

[0008] The size of the metal oxide nanoparticles may be 3 nm to 20 nm.

[0009] The metal oxide nanoparticles may be one of ZnMgO, ZnLiO, ZnAlO, and ZnGaO.

[0010] According to one embodiment, a method for producing ZnMgO nanoparticles includes synthesizing ZnMgO using a Sol-Gel method at a temperature of 10° C. or less, and adding an amine to the synthesized ZnMgO.

[0011] The prepared ZnMgO nanoparticles may include alkylamine ligands having 8 to 18 carbon atoms located on the surface.

[0012] The method may further include adding Mg to the synthesized ZnMgO and performing a surface treatment.

[0013] The size of the produced ZnMgO nanoparticles may be 3 nm to 20 nm.

[0014] The size deviation of the prepared ZnMgO nanoparticles may be within 15% based on the median value.

[0015] The size of the ZnMgO nanoparticles can be increased by adding amine to the synthesized ZnMgO.

[0016] According to another embodiment, a method for producing ZnMgO nanoparticles includes synthesizing ZnO using a Sol-Gel method at a temperature of 10°C or less, adding Mg to the synthesized ZnO to obtain ZnMgO, and adding an amine to the obtained ZnMgO.

[0017] The prepared ZnMgO nanoparticles may include alkylamine ligands having 8 to 18 carbon atoms located on the surface.

[0018] The size of the produced ZnMgO nanoparticles may be 3 nm to 20 nm.

[0019] The deviation of the size of the prepared ZnMgO nanoparticles may be within 15% based on the median value.

[0020] According to one embodiment, a light-emitting device includes a first electrode, an electron transport layer located on the first electrode, a light-emitting layer located on the electron transport layer, a hole transport layer located on the light-emitting layer, and a second electrode located on the hole transport layer, wherein the electron transport layer includes metal oxide nanoparticles, and the metal oxide nanoparticles include a compound represented by the following Chemical Formula 1 and an alkylamine ligand having 8 to 18 carbon atoms located on a surface of the compound:

[0021] [Chemical formula 1] ZnMo

[0022] In the above formula 1, M may be one of Ca, Zr, Al, Li, Mg, Ni, Y, W, Co, and Ga.

[0023] The size of the metal oxide nanoparticles may be 3 nm to 20 nm.

[0024] The metal oxide nanoparticles may be one or more of ZnMgO, ZnLiO, ZnAlO, and ZnGaO.

[0025] The deviation of the size of the metal oxide nanoparticles contained in the electron transport layer may be within 15% based on the median value.

[0026] The first electrode may be a reflective electrode, and the second electrode may be a semi-transparent electrode.

[0027] The first electrode may be a semi-transparent electrode, and the second electrode may be a reflective electrode. [Effects of the Invention]

[0028] According to the embodiments, there are provided metal oxide nanoparticles, a method for producing the same, and a light-emitting device having improved light-emitting properties due to the inclusion of metal oxide nanoparticles. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a process flow chart showing a process for producing metal oxide nanoparticles according to the present embodiment. [Figure 2] 1 is an image of ZnMgO nanoparticles without amine treatment. [Figure 3] 1 is an image of amine-treated ZnMgO nanoparticles. [Figure 4] 4 shows absorption spectra as a function of wavelength for the ZnMgO nanoparticles of FIG. 2 (Example 1) and the ZnMgO nanoparticles of FIG. 3 (Example 2). [Figure 5] 1 illustrates a process for producing ZnMgO nanoparticles according to one embodiment. [Figure 6] ZnO nanoparticles without amine treatment are shown. [Figure 7] ZnMgO nanoparticles with Mg surface treatment and amine treatment are shown. [Figure 8] 8 shows the absorption spectra as a function of wavelength for the ZnO nanoparticles of FIG. 6 (Example 3) and the ZnMgO nanoparticles of FIG. 7 (Example 4). [Figure 9] 1 shows the absorption spectra of ZnMgO nanoparticles prepared by the Sol-Gel method at room temperature (25° C.) before and after amine treatment. [Figure 10] 1 is a simplified illustration of a light emitting device according to one embodiment. [Figure 11] 1 shows JV graphs for Example 8, which contains amine-treated metal oxide nanoparticles, and Example 7, which contains non-amine-treated metal oxide nanoparticles. [Figure 12] 1 shows the luminous efficiency for Example 8 containing amine-treated metal oxide nanoparticles and Example 7 containing non-amine-treated metal oxide nanoparticles. DETAILED DESCRIPTION OF THE INVENTION

[0030] The present invention may, however, be embodied in various different forms and is not limited to the embodiments set forth herein.

[0031] In order to clearly explain the present invention, parts that are not necessary for the explanation will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0032] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for the convenience of explanation, and the present invention is not necessarily limited to those shown in the drawings. In the drawings, thicknesses are exaggerated to clearly show various layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for the convenience of explanation.

[0033] Furthermore, when a layer, film, region, plate, or other part is said to be "on" or "above" another part, this includes not only the case where it is "directly on" another part, but also the case where there is another part in between. Conversely, when a part is said to be "directly on" another part, it means that there is no other part in between. Furthermore, being "on" or "above" a reference part means being placed above or below the reference part, and does not necessarily mean being placed "on" or "above" in the opposite direction of gravity.

[0034] Furthermore, throughout the specification, when a part is said to "comprise" a certain element, this does not mean that it excludes other elements, but that it may further include other elements, unless otherwise specified.

[0035] Also, throughout the specification, "in a plane" means when the subject part is viewed from above, and "in cross section" means when the subject part is cut vertically and viewed from the side.

[0036] Hereinafter, metal oxide nanoparticles according to an embodiment, a method for manufacturing the same, and a display device including such metal oxide nanoparticles will be described in detail with reference to the accompanying drawings.

[0037] According to one embodiment, the metal oxide nanoparticles may be a compound represented by the following Chemical Formula 1:

[0038] [Chemical formula 1] ZnMo

[0039] In the above formula 1, M may be one of Ca, Zr, Al, Li, Mg, Ni, Y, W, Co, and Ga.

[0040] The compound of Chemical Formula 1 may be in the form of ZnO doped with the metal represented by M, and more specifically, may be a compound represented by the following Chemical Formula 2, reflecting the doping concentration.

[0041] [Chemical formula 2] Zn (1-x) M x O

[0042] In the above Chemical Formula 2, M may be one of Ca, Zr, Al, Li, Mg, Ni, Y, W, Co, and Ga. Here, x may be 0.01 to 0.5. That is, the doping concentration of M with respect to ZnO may be up to 50%.

[0043] The metal oxide nanoparticles according to this embodiment may also include alkylamine ligands located on the surface, where the alkylamine may have 8 to 18 carbon atoms.

[0044] Furthermore, the size of the metal oxide nanoparticles according to this embodiment may be 3 nm to 20 nm. More specifically, it may be 5 nm to 20 nm. As will be described separately below, the metal oxide nanoparticles according to this embodiment are characterized by increasing the size of the metal oxide nanoparticles and the content of the doping material (M) through amine treatment. For example, when M is Mg, ZnMgO without amine treatment has a particle size of about 3 nm, but when amine treatment is performed, the particle size can increase to about 5 nm or more.

[0045] The metal oxide nanoparticles according to this embodiment are formed by amine treatment, and have alkylamine ligands located on the surface. Here, the alkylamine may have 8 to 18 carbon atoms. If the alkylamine has 8 or fewer carbon atoms, dispersibility in non-polar solvents decreases, which is undesirable. If the alkylamine has 18 or more carbon atoms, the influence of the ligand increases, which can reduce conductivity. That is, when the metal oxide nanoparticles according to this embodiment are used as an electron transport layer of a light-emitting device, if the alkylamine has 18 or more carbon atoms, electrical conductivity decreases, and a higher voltage must be applied.

[0046] Table 1 below shows the results of measuring the dispersibility and conductivity depending on the carbon number of the alkylamine ligand located on the surface of the metal oxide nanoparticles according to this embodiment. Referring to Table 1 below, when the carbon number is 8 or less, the dispersibility in octane decreases, and when the carbon number is 18 or more, the electrical conductivity decreases, so that the dispersibility at the same current (5 mA / cm 2 ) was confirmed to flow.

[0047] [Table 1]

[0048] A method for producing metal oxide nanoparticles according to one embodiment of the present invention will now be described. FIG. 1 is a process flowchart illustrating a process for producing metal oxide nanoparticles according to this embodiment. FIG. 1 illustrates an example in which the metal oxide nanoparticles are ZnMgO. Referring to FIG. 1, first, a first solution is prepared (S10). Here, the first solution may be a solution in which zinc acetate dihydrate and magnesium acetate tetrahydrate are dissolved in DMSO. That is, the first solution may be a solution containing a Zn precursor and an Mg precursor. The type of precursor and the solvent may vary depending on the embodiment.

[0049] Also, a second solution is prepared (S20). At this time, the second solution may be a solution in which TMAH (tetramethylammonium hydroxide) is dissolved in ethanol.

[0050] Next, the second solution is added dropwise to the first solution and stirred (S30), and then the ZnMgO thus formed is obtained (S40).

[0051] In this case, the ZnMgO formation steps (S10, S20, S30, S40) can be performed at temperatures below 10°C. If ZnMgO is formed at room temperature (25°C), the particle size does not change even if the subsequent amine treatment is performed. However, as mentioned above, if ZnMgO is formed at temperatures below 10°C, the particle size increases due to the subsequent amine treatment.

[0052] Next, a third solution is prepared (S50). The third solution may be a solution of magnesium acetate tetrahydrate dissolved in ethanol (EtOH). The third solution is used for surface treatment of ZnMgO.

[0053] This third solution is mixed with the previously prepared ZnMgO (S60).

[0054] Next, an amine is added to obtain ZnMgO (S70), where the amine may be a primary amine, a secondary amine, or a tertiary amine.

[0055] That is, in the method for manufacturing metal oxide nanoparticles according to this embodiment, ZnMgO is formed using the Sol-Gel method at a temperature of 10° C. or less, and then alkylamine is formed on the surface through an amine treatment. Through this manufacturing process, it is possible to increase the size, uniformity, and doping concentration of metal oxide nanoparticles.

[0056] 2 is an image of ZnMgO nanoparticles that have not been subjected to an amine treatment. That is, the ZnMgO nanoparticles according to the embodiment of FIG. 2 are particles manufactured through the manufacturing process from steps S10 to S40 of FIG.

[0057] 3 is an image of amine-treated ZnMgO nanoparticles. That is, the ZnMgO nanoparticles according to the embodiment of FIG. 3 are particles manufactured through the manufacturing process from steps S10 to S70 of FIG.

[0058] Comparing the sizes of the ZnMgO nanoparticles in Figures 2 and 3, it was confirmed that the size of the ZnMgO nanoparticles in Figure 3 was larger than that in Figure 2. It was also shown that the Mg content in the nanoparticles in Figure 3 was higher than that in the nanoparticles in Figure 2.

[0059] Table 2 shows the Mg content and particle size of the ZnMgO nanoparticles of FIG. 2 and the ZnMgO nanoparticles of FIG.

[0060] [Table 2]

[0061] As can be seen from Table 2, the size of ZnMgO nanoparticles increases and the Mg content also increases after amine treatment. As the size of metal oxide nanoparticles increases and the dopant (Mg) content increases, the luminous efficiency of light-emitting devices containing such metal oxide nanoparticles improves.

[0062] In addition, as can be seen from Table 2, the size distribution of the ZnMgO nanoparticles prepared according to this embodiment was 5.5±0.8 nm, which was within 15% of the median value of 5.5 nm. In other words, it was confirmed that the method of preparing ZnMgO nanoparticles according to this embodiment produces ZnMgO nanoparticles with a uniform particle size.

[0063] Figure 4 shows the wavelength-dependent absorption spectra of the ZnMgO nanoparticles of Figure 2 (Example 1) and the ZnMgO nanoparticles of Figure 3 (Example 2). As can be seen in Figure 4, the absorption spectrum shifts to the right as the particle size changes. That is, because the ZnMgO nanoparticles of Figure 3 are larger than the ZnMgO nanoparticles of Figure 2, the peak of the absorption spectrum also red-shifted.

[0064] 1 to 4, an embodiment in which ZnMgO nanoparticles are formed and then subjected to an amine treatment is described, but in some embodiments, ZnMgO nanoparticles can be formed by forming ZnO nanoparticles and then performing an Mg surface treatment and an amine treatment. Such an embodiment will be described below.

[0065] 5 illustrates a process for preparing ZnMgO nanoparticles according to one embodiment. Referring to FIG. 5, a first solution is first prepared (S10). The first solution may be a solution in which Zn acetate dihydrate is dissolved in DMSO. That is, the first solution may be a solution containing a Zn precursor. The type of precursor and the solvent may vary depending on the embodiment.

[0066] A second solution is prepared (S20). At this time, the second solution may be a solution in which TMAH is dissolved in ethanol.

[0067] Next, the second solution is added dropwise to the first solution and stirred (S30).

[0068] Thereafter, the ZnO thus formed is obtained (S40).

[0069] In this case, the ZnO formation processes (S10, S20, S30, S40) can be performed at 10°C or below. As mentioned above, when ZnO is formed at room temperature (25°C), the particle size does not change even without amine treatment. However, when ZnO is formed at a temperature below 10°C, the particle size increases due to the amine treatment described below.

[0070] Next, a third solution is prepared (S50). The third solution may be a solution of Mg acetate tetrahydrate dissolved in EtOH.

[0071] This third solution is mixed with the previously prepared ZnO (S60), and the third solution is used for the surface treatment of ZnO.

[0072] An amine is then added to obtain ZnMgO (S70), where the amine may be a primary amine, a secondary amine, or a tertiary amine.

[0073] That is, the method for manufacturing metal oxide nanoparticles according to this embodiment involves forming ZnO using a sol-gel method at a temperature of 10°C or less, then surface-treating the ZnMgO with Mg, and then forming alkylamine on the surface through amine treatment. Through this manufacturing process, it is possible to increase the size, uniformity, and doping concentration of the metal oxide nanoparticles.

[0074] 6 shows ZnO nanoparticles that are not subjected to an amine treatment, that is, the ZnO nanoparticles according to the embodiment of FIG. 6 are particles manufactured through the manufacturing process of steps S10 to S40 of FIG.

[0075] 7 shows ZnMgO nanoparticles that have been subjected to Mg surface treatment and amine treatment. That is, the ZnMgO nanoparticles according to the embodiment of FIG. 7 are particles manufactured through the manufacturing process from steps S10 to S70 of FIG.

[0076] Comparing the sizes of the nanoparticles in FIGS. 6 and 7, it was confirmed that the size of the nanoparticles in FIG. 7 was larger than that in FIG.

[0077] Also, the nanoparticles in FIG. 6 do not contain Mg, but the nanoparticles in FIG. 7 contain Mg due to the Mg treatment.

[0078] Table 3 shows the Mg content and particle size for the nanoparticles of FIGS.

[0079] [Table 3]

[0080] As can be seen from Table 3, the size of ZnMgO nanoparticles increases and the Mg content increases after amine treatment. As will be explained later, the increase in size of metal oxide nanoparticles and the increase in the dopant (Mg) content improves the luminous efficiency of light-emitting devices containing such metal oxide nanoparticles.

[0081] In addition, as can be seen from Table 3, the size distribution of the ZnMgO nanoparticles prepared according to this embodiment was 10.5±1.2 nm, which was within 15% of the median value of 10.5 nm. In other words, it was confirmed that the method of preparing ZnMgO nanoparticles according to this embodiment produces ZnMgO nanoparticles with a uniform particle size.

[0082] Figure 8 shows the wavelength-dependent absorption spectra for the ZnO nanoparticles of Figure 6 (Example 3) and the ZnMgO nanoparticles of Figure 7 (Example 4). As can be seen in Figure 8, the absorption spectrum shifts to the right as the particle size changes. That is, because the ZnMgO nanoparticles of Figure 7 are larger in size than the ZnO nanoparticles of Figure 6, the peak of the absorption spectrum also red-shifts.

[0083] As mentioned above, the formation of ZnO or ZnMgO nanoparticles before amine treatment is carried out at a temperature below 10° C. If the formation of ZnO or ZnMgO nanoparticles is carried out at a temperature above 10° C., it is possible that the size of the nanoparticles does not increase even after amine treatment.

[0084] FIG. 9 shows the absorption spectra of ZnMgO nanoparticles prepared using the Sol-Gel method at room temperature (25°C) before and after amine treatment. Example 5 in FIG. 9 shows ZnMgO nanoparticles prepared at room temperature that were not subjected to amine treatment, while Example 6 in FIG. 9 shows ZnMgO nanoparticles prepared at room temperature that were subjected to amine treatment. Referring to FIG. 9, it was confirmed that when ZnMgO nanoparticles are formed at room temperature, no peak shift in the absorption spectrum occurs before and after amine treatment. In FIG. 9, no peak shift is observed in the absorption spectra for Examples 5 and 6. This means that the size of the ZnMgO nanoparticles does not increase even after amine treatment for ZnMgO prepared at room temperature.

[0085] That is, in the cases of Figures 4 and 8, where nanoparticles were produced at temperatures below 10°C, a red shift in the absorption spectrum peak was observed before and after amine treatment. However, in the case of Figure 9, where nanoparticles were produced at room temperature, no red shift in the absorption spectrum peak was observed before and after amine treatment. Therefore, it was confirmed that synthesizing ZnO or ZnMgO nanoparticles at temperatures below 10°C is an important factor.

[0086] The metal oxide nanoparticles prepared by the above method, which have a large size and an increased dopant content, can be used as an electron transport layer of a light emitting device, and when used as an electron transport layer, the light emitting characteristics of the light emitting device can be improved.

[0087] The effects of the present invention on various doping and amine treating materials are described below.

[0088] Table 4 shows the doping material content and particle size change before and after amine treatment for various amine treatment materials and doping materials. The relative device efficiency was also measured and shown. While the above examples focused on the case where the doping material was Mg, the following experiments will be conducted with the doping materials Mg, Li, Al, and Ga, and the results will be described.

[0089] [Table 4]

[0090] Referring to Table 4 above, it was confirmed that even when the doping material was Li, Al, or Ga, the particle size increased after the amine treatment, and the relative efficiency after the amine treatment was higher than that before the amine treatment. In Table 4, the relative device efficiency is shown as the efficiency of each experimental example, with the efficiency before the amine treatment set to 1. As shown in Table 4, even when the doping material was a variety of other metals, it was confirmed that the particle size increased overall and the relative device efficiency was improved. In this regard, it was confirmed that the doping material content was higher and the relative device efficiency was superior when the amine treatment was performed with ZnMO (M is one of Mg, Li, Al, and Ga) than when the amine treatment was performed with ZnO. Hereinafter, a light-emitting device including metal oxide nanoparticles according to this embodiment will be described.

[0091] 10 is a simplified diagram of a light emitting device according to an embodiment. Referring to FIG. 10, the light emitting device according to this embodiment may include a first electrode 191, a hole transport layer HTL, an emission layer EML, an electron transport layer ETL, and a second electrode 270.

[0092] The first electrode 191 and the second electrode 270 may include a conductive oxide such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc tin oxide (ZTO), copper indium oxide (CIO), copper zinc oxide (CZO), gallium zinc oxide (GZO), aluminum zinc oxide (AZO), tin oxide (SnO), zinc oxide (ZnO), or a combination thereof, calcium (Ca), ytterbium (Yb), aluminum (Al), silver (Ag), magnesium (Mg), samarium (Sm), titanium (Ti), gold (Au), or an alloy thereof, graphene, carbon nanotubes, or a conductive polymer such as PEDOT:PSS. However, the first electrode 191 and the second electrode 270 are not limited thereto and may also be formed as a stacked structure of two or more layers.

[0093] In one embodiment, the first electrode 191 may be a reflective electrode having an ITO / Ag / ITO structure, and the second electrode 270 may be a semi-transparent electrode containing AgMg. Light generated in the emitting layer EML is reflected by the first electrode 191, which is a reflective electrode, and resonates and is amplified between the second electrode 270, which is a semi-transparent electrode, and the first electrode 191. The resonated light is reflected by the first electrode 191 and emitted to the upper surface of the second electrode 270.

[0094] Alternatively, the second electrode 270 may be a reflective electrode having an ITO / Ag / ITO structure, and the first electrode 191 may be a semi-transparent electrode containing AgMg. Light generated in the emitting layer EML is reflected by the second electrode 270, which is a reflective electrode, and resonates between the first electrode 191, which is a semi-transparent electrode, and the second electrode 270, and is amplified. The resonated light is reflected by the second electrode 270 and emitted to the upper surface of the first electrode 191.

[0095] In one embodiment, the second electrode 270 may include an alloy of two or more materials selected from the group consisting of Ag, Mg, Al, and Yb. More specifically, the second electrode 270 may include AgMg, and in this case, the Ag content in the second electrode 270 may be greater than the Mg content. In this case, the Mg content may be approximately 10% by volume. The thickness of the second electrode 270 may range from 80 angstroms to 120 angstroms. In addition, the second electrode 270 may include AgYb, and in this case, the Yb content may be approximately 10% by volume. However, this is merely an example and is not intended to be limiting.

[0096] The hole transport layer HTL was prepared using m-MTDATA, TDATA, 2-TNATA, NPB (NPD), β-NPB, TPD, Spiro-TPD, Spiro-NPB, methylated NPB, TAPC, HMTPD, TCTA (4,4',4"-tris(N-carbazolyl)triphenylamine), Pani / DBSA (Polyaniline / Dodecylbenzenesulfonic acid), PEDOT / PSS (Poly(3,4-ethylenedioxythiophene) / Poly(4-styrenesulfonate)), Pani / CSA (Polyaniline / Camphor sulfonic acid), and The hole transport layer may include one or more of polyaniline / camphorsulfonic acid (PANI / PSS), polyaniline / poly(4-styrenesulfonate) (PANI / PSS), or an alkali metal halide or an alkaline earth metal halide.

[0097] The light-emitting layer EML may include an organic material or an inorganic material. The light-emitting layer may include quantum dots. For example, the quantum dots may include at least one of Zn, Te, Se, Cd, In, and P. The quantum dots may include a core including at least one of Zn, Te, Se, Cd, In, and P, and a shell located on a portion of the core and having a different composition from the core.

[0098] Specifically, the quantum dots can be selected from group II-VI compounds, group I-III-VI compounds, group III-V compounds, group IV-VI compounds, group IV elements, group IV compounds, and combinations thereof.

[0099] The quantum dots may be selected from the group consisting of II-VI compounds CdSe, CdTe, CdS, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, MgSe, MgS, and mixtures thereof, binary compounds CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdH The compound may be selected from the group consisting of ternary compounds selected from the group consisting of HgZnTe, HgZnS, HgZnSe, HgZnTe, MgZnSe, MgZnS, and mixtures thereof, and quaternary compounds selected from the group consisting of HgZnTeS, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, and mixtures thereof.

[0100] The quantum dots may be selected from ternary compounds selected from the group consisting of I-III-VI compounds AgInS, CuInS, AgGaS, CuGaS, and mixtures thereof, or quaternary compounds such as AgInGaS, CuInGaS.

[0101] The III-V compounds include binary compounds selected from the group consisting of GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, and mixtures thereof; ternary compounds selected from the group consisting of GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InGaP, InAlP, InNP, InNAs, InNSb, InPAs, InPSb, and mixtures thereof; and and quaternary compounds selected from the group consisting of GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb, and mixtures thereof, while the III-V compound may further comprise a Group II metal (e.g., InZnP) and may be selected from these compounds.

[0102] The IV-VI compound may be selected from the group consisting of a binary compound selected from the group consisting of SnS, SnSe, SnTe, PbS, PbSe, PbTe, and mixtures thereof, a ternary compound selected from the group consisting of SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, and mixtures thereof, and a quaternary compound selected from the group consisting of SnPbSSe, SnPbSeTe, SnPbSTe, and mixtures thereof. The group IV element may be selected from the group consisting of Si, Ge, and mixtures thereof, and the group IV compound may be a binary compound selected from the group consisting of SiC, SiGe, and mixtures thereof.

[0103] The electron transport layer (ETL) may include the metal oxide nanoparticles described above. Detailed description of the same components will be omitted. That is, the electron transport layer (ETL) may include metal oxide nanoparticles, which are compounds represented by the following Chemical Formula 1:

[0104] [Chemical formula 1] ZnMo

[0105] In the above formula 1, M may be one of Ca, Zr, Al, Li, Mg, Ni, Y, W, Co, and Ga.

[0106] The metal oxide nanoparticles according to this embodiment may also include alkylamine ligands located on the surface, where the alkylamine may have 8 to 18 carbon atoms.

[0107] The size of the metal oxide nanoparticles according to this embodiment may be 3 nm to 20 nm, more specifically 5 nm to 20 nm.

[0108] That is, the metal oxide nanoparticles contained in the electron transport layer ETL of the light-emitting device according to this embodiment have alkylamine ligands having 8 to 18 carbon atoms disposed on their surfaces by the amine treatment described above, which can increase the luminous efficiency of the light-emitting device.

[0109] Table 5 below shows the results of measuring the current efficiency of light-emitting devices containing the ZnMgO nanoparticles of FIG. 2 and the ZnMgO nanoparticles of FIG. 3 in the electron transport layer.

[0110] [Table 5]

[0111] As can be seen from Table 5 above, Example 8, which contains amine-treated metal oxide nanoparticles, showed an increase in device current efficiency compared to Example 7, which contains non-amine-treated metal oxide nanoparticles.

[0112] 11 shows a JV graph for Example 8 containing amine-treated metal oxide nanoparticles and Example 7 containing non-amine-treated metal oxide nanoparticles. Referring to FIG. 11, it can be seen that Example 8 containing amine-treated metal oxide nanoparticles has improved efficiency compared to Example 7 containing non-amine-treated metal oxide nanoparticles.

[0113] Figure 12 shows the luminous efficiency of Example 8, which includes amine-treated metal oxide nanoparticles, and Example 7, which includes non-amine-treated metal oxide nanoparticles. Referring to Figure 12, it can be seen that Example 8, which includes amine-treated metal oxide nanoparticles, has improved efficiency compared to Example 7, which includes non-amine-treated metal oxide nanoparticles.

[0114] As described above, the metal oxide nanoparticles according to this embodiment have alkylamine ligands having 8 to 18 carbon atoms located on the surface, and such metal oxide nanoparticles can be formed at a temperature of 10° C. or less. The size of the metal oxide nanoparticles formed in this manner increases due to the amine treatment, and the content of the dopant (M) increases. When the metal oxide nanoparticles produced by this method are applied to the electron transport layer of a light-emitting device, the luminous efficiency is improved.

[0115] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited to these, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention.

Claims

1. Metal oxide nanoparticles comprising a compound represented by the following chemical formula 1 and an alkylamine ligand having 8 to 18 carbon atoms positioned on the surface of the compound: [Chemical formula 1] ZnMo In the above formula 1, M may be one of Ca, Zr, Al, Li, Mg, Ni, Y, W, Co, and Ga.

2. The metal oxide nanoparticles according to claim 1, wherein the size of the metal oxide nanoparticles is 3 nm to 20 nm.

3. 2. The metal oxide nanoparticles of claim 1, wherein the metal oxide nanoparticles are one of ZnMgO, ZnLiO, ZnAlO, and ZnGaO.

4. Synthesizing ZnMgO using a sol-gel method at a temperature of 10°C or less; and adding an amine to the synthesized ZnMgO.

5. The method for producing ZnMgO nanoparticles according to claim 4, wherein the produced ZnMgO nanoparticles contain alkylamine ligands having 8 to 18 carbon atoms located on the surface.

6. The method for producing ZnMgO nanoparticles according to claim 4 , further comprising the step of adding Mg to the synthesized ZnMgO to perform a surface treatment.

7. The method for producing ZnMgO nanoparticles according to claim 4, wherein the size of the produced ZnMgO nanoparticles is 3 nm to 20 nm.

8. The method for producing ZnMgO nanoparticles according to claim 4, wherein the deviation of the size of the produced ZnMgO nanoparticles is within 15% based on the median.

9. The method of claim 4, wherein the size of the ZnMgO nanoparticles is increased by adding an amine to the synthesized ZnMgO.

10. synthesizing ZnO using a Sol-Gel method at a temperature below 10°C; adding Mg to the synthesized ZnO to obtain ZnMgO; adding an amine to the obtained ZnMgO.

11. The method for producing ZnMgO nanoparticles according to claim 10, wherein the produced ZnMgO nanoparticles contain alkylamine ligands having 8 to 18 carbon atoms located on the surface.

12. The method for producing ZnMgO nanoparticles according to claim 10, wherein the produced ZnMgO nanoparticles have a size of 3 nm to 20 nm.

13. The method for producing ZnMgO nanoparticles according to claim 10, wherein the deviation of the size of the produced ZnMgO nanoparticles is within 15% based on the median.

14. The method of claim 10, wherein the size of the ZnMgO nanoparticles is increased by adding an amine to the synthesized ZnMgO.

15. first electrode; an electron transport layer overlying the first electrode; an emissive layer overlying the electron transport layer; a hole transport layer overlying the light-emitting layer; a second electrode overlying the hole transport layer; the electron transport layer comprises metal oxide nanoparticles; The metal oxide nanoparticles include a compound represented by the following Chemical Formula 1, and an alkylamine ligand having 8 to 18 carbon atoms located on the surface of the compound: [Chemical formula 1] ZnMo In the above formula 1, M may be one of Ca, Zr, Al, Li, Mg, Ni, Y, W, Co, and Ga.

16. The light-emitting device according to claim 15, wherein the size of the metal oxide nanoparticles is 3 nm to 20 nm.

17. The light-emitting device of claim 15, wherein the metal oxide nanoparticles are one or more of ZnMgO, ZnLiO, ZnAlO, and ZnGaO.

18. The light emitting device of claim 15, wherein the deviation of the size of the metal oxide nanoparticles contained in the electron transport layer is within 15% based on the median.

19. The light-emitting device according to claim 15 , wherein the first electrode is a reflective electrode and the second electrode is a semi-transparent electrode.

20. The light-emitting device according to claim 15 , wherein the first electrode is a semi-transparent electrode and the second electrode is a reflective electrode.

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