Light-emitting element

Abstract

A light-emitting element (1) comprises a positive electrode (11) and a negative electrode (16), and further comprises at least one functional layer that is located between the positive electrode (11) and the negative electrode (16) and includes a 1O2 scavenger (31), which is an aprotic singlet-oxygen scavenger.

Description

[Technical Field]

[0001] This disclosure concerns light-emitting elements. to child To relate to. [Background technology]

[0002] A light-emitting element called a QLED (Quantum Dot Light-Emitting Diode) uses quantum dots as the light-emitting material in its light-emitting layer.

[0003] Quantum dots are known to degrade due to oxygen. Within a light-emitting device, there is oxygen from the atmosphere that has entered the device, oxygen from the solvent that remains inside the device, and oxygen contained in the material.

[0004] In the presence of a photosensitizer, when ground-state oxygen (triplet oxygen) is irradiated with excitation light such as ultraviolet light, the triplet oxygen is excited, and singlet oxygen is generated. Quantum dots function as photosensitizers. Many photosensitizers are compounds that transition from the ground state to a singlet excited state by absorption, and then rapidly undergo intersystem crossing to a triplet excited state. Singlet oxygen oxidizes quantum dots.

[0005] Quantum dots are sometimes referred to as semiconductor nanoparticles because their composition is derived from semiconductor materials. Patent Document 1 discloses that singlet oxygen can be removed by coordinating an antioxidant ligand to the surface of semiconductor nanoparticles, thereby suppressing the degradation of the semiconductor nanoparticles. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2017-025220 [Overview of the project] [Problems that the invention aims to solve]

[0007] However, when an antioxidant ligand is coordinated to a quantum dot, for example, the dispersibility of the quantum dot changes, which has the problem of reducing the luminescence characteristics and reliability when the quantum dot is used in a light-emitting device.

[0008] One aspect of this disclosure aims to provide a light-emitting element and a method for manufacturing the same that suppress the degradation of quantum dots by singlet oxygen and have high luminous efficiency and reliability. [Means for solving the problem]

[0009] To solve the above problems, a light-emitting element according to one aspect of the present disclosure comprises a first electrode and a second electrode, and at least one functional layer containing an aprotic singlet oxygen scavenger is provided between the first electrode and the second electrode.

[0010] To solve the above problems, a light-emitting element according to one aspect of the present disclosure comprises a first electrode and a second electrode, and comprises at least one functional layer between the first electrode and the second electrode, the functional layer comprising at least one compound selected from the group consisting of tertiary amines, carotenoids, ethylenic compounds, naphthalene and its derivatives, and anthracene and its derivatives.

[0011] To solve the above problems, a method for manufacturing a light-emitting element according to one aspect of the present disclosure is a method for manufacturing a light-emitting element comprising a first electrode and a second electrode, and having at least one functional layer between the first electrode and the second electrode, the method comprising a functional layer formation step for forming the at least one functional layer, wherein at least one functional layer comprising an aprotic singlet oxygen scavenger is formed as the functional layer.

[0012] To solve the above problems, a method for manufacturing a light-emitting element according to one aspect of the present disclosure is a method for manufacturing a light-emitting element comprising a first electrode and a second electrode, and having at least one functional layer between the first electrode and the second electrode, the method comprising a functional layer formation step for forming the at least one functional layer, wherein at least one functional layer is formed as the functional layer, and the functional layer comprises at least one compound selected from the group consisting of tertiary amines, carotenoids, ethylenic compounds, naphthalene and its derivatives, and anthracene and its derivatives. [Effects of the Invention]

[0013] According to one aspect of this disclosure, it is possible to suppress the degradation of quantum dots by singlet oxygen and provide a light-emitting element and a method for manufacturing the same that have high luminescence efficiency and reliability. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic cross-sectional view showing an example of a light-emitting element according to Embodiment 1. [Figure 2] Figure 1 is a flowchart showing the method for manufacturing a light-emitting element. [Figure 3] This is a schematic cross-sectional view showing an example of a light-emitting element according to Embodiment 2. [Figure 4] Figure 3 shows a flowchart illustrating the method for manufacturing a light-emitting element. [Figure 5] This is a schematic cross-sectional view showing an example of a light-emitting element according to Embodiment 3. [Figure 6] Figure 5 is a flowchart showing the method for manufacturing a light-emitting element. [Figure 7] This is a schematic cross-sectional view showing an example of a light-emitting element according to a modified example 1 of Embodiment 3. [Figure 8] This is a schematic cross-sectional view showing an example of a light-emitting element according to a modified example 2 of Embodiment 3. [Figure 9] This is a schematic cross-sectional view showing an example of a light-emitting element according to Embodiment 4. [Modes for carrying out the invention]

[0015] An embodiment of this disclosure will be described in detail below. Hereinafter, a layer formed in a process earlier than the layer being compared will be referred to as the "lower layer," and a layer formed in a process later than the layer being compared will be referred to as the "upper layer." In the following description, the notation "A to B" for two numbers A and B means "greater than or equal to A and less than or equal to B" unless otherwise specified. Furthermore, the composition shown by chemical formula in this disclosure is preferably stoichiometric; however, this does not exclude the possibility of a composition other than stoichiometric.

[0016] Furthermore, for the sake of clarity, in the following explanation, components having the same function as those described earlier will be denoted by the same reference numerals, and their descriptions will not be repeated. In the embodiments described later, from Embodiment 2 onwards, the differences from the embodiments described earlier will be explained. It goes without saying that, even if not specifically explained, the same modifications as in the embodiments described earlier are possible in Embodiment 2 and later.

[0017] A light-emitting element according to one aspect of this disclosure comprises a first electrode, a second electrode, and at least one functional layer provided between the first electrode and the second electrode. In this disclosure, the layer between the first electrode and the second electrode is collectively referred to as the functional layer.

[0018] The above-mentioned functional layer may be a single-layer type consisting only of a light-emitting layer, or it may be a multi-layer type including a light-emitting layer and functional layers other than the light-emitting layer.

[0019] The above-mentioned light-emitting element is a self-emitting element referred to as a nanoLED (light-emitting diode) or QLED (quantum dot light-emitting diode), and the light-emitting layer in the above-mentioned light-emitting element is a quantum dot light-emitting layer containing quantum dots as a light-emitting material. Therefore, the above-mentioned light-emitting element either includes the quantum dot light-emitting layer as the functional layer, or includes the quantum dot light-emitting layer and a first functional layer other than the quantum dot light-emitting layer.

[0020] The first electrode and the second electrode are configured such that one is the anode and the other is the cathode. The light-emitting element may have a conventional structure in which the anode is the lower electrode and the cathode is the upper electrode, or it may have an inverted structure in which the cathode is the lower electrode and the anode is the upper electrode.

[0021] The above-described light-emitting device comprises at least one functional layer containing an aprotic singlet oxygen scavenger between the first electrode and the second electrode. The functional layer containing the aprotic singlet oxygen scavenger may be a light-emitting layer or the first functional layer. For example, in the above-described light-emitting device, at least one of the light-emitting layer and the first functional layer, which are included in the at least one functional layer, contains an aprotic singlet oxygen scavenger.

[0022] Therefore, the above-mentioned method for manufacturing a light-emitting element comprises a first electrode and a second electrode, and at least one functional layer between the first electrode and the second electrode, and includes a functional layer formation step for forming the at least one functional layer. In the functional layer formation step, at least one functional layer containing an aprotic singlet oxygen scavenger is formed as the functional layer. For example, in the functional layer formation step, at least one of the light-emitting layer containing the aprotic singlet oxygen scavenger and the first functional layer containing the aprotic singlet oxygen scavenger is formed.

[0023] According to one aspect of this disclosure, by forming at least one functional layer containing an aprotic singlet oxygen scavenger as the functional layer, degradation of quantum dots due to singlet oxygen can be suppressed, and a light-emitting element with high luminescence efficiency and reliability can be provided. For example, by including at least one of the light-emitting layer and the first functional layer in the at least one functional layer containing an aprotic singlet oxygen scavenger, degradation of quantum dots due to singlet oxygen can be suppressed, and a light-emitting element with high luminescence efficiency and reliability can be provided.

[0024] Hereafter, the light-emitting layer will be referred to as "EML" and quantum dots as "QD". Furthermore, functional layers other than the EML will be referred to as the "first functional layer". Also, singlet oxygen will be referred to as 1 It is written as "O2" and the singlet oxygen scavenger is " 1 It is labeled as "O2 scavenger".

[0025] [Embodiment 1] Below is an example of EML 1 The above-mentioned light-emitting element will be explained in more detail, using the case where an O2 scavenger is included as an example.

[0026] (Schematic configuration of the light-emitting element) Figure 1 is a schematic cross-sectional view showing an example of a light-emitting element 1 according to this embodiment.

[0027] Hereafter, the electron transport layer will be referred to as "ETL," the hole transport layer as "HTL," and the hole injection layer as "HIL."

[0028] The light-emitting element 1 shown in Figure 1 is equipped with an anode 11, HIL 12, HTL 13, EML 14, ETL 15, and cathode 16 in this order from the bottom layer.

[0029] In Figure 1, as an example, the light-emitting element 1 is shown with a conventional structure in which the anode 11 is the lower electrode and the cathode 16 is the upper electrode. However, this embodiment is not limited to this. As described above, the light-emitting element 1 may have an inverted structure in which the cathode 16 is the lower electrode and the anode 11 is the upper electrode. In this case, the stacking order of the functional layers is reversed from that in Figure 1. That is, the light-emitting element 1 may have a configuration in which the cathode 16, ETL 15, EML 14, HTL 13, HIL 12, and anode 11 are stacked in this order from the bottom.

[0030] In Figure 1, the anode 11 is formed on the substrate 10. The substrate 10 functions as a support for each layer from the anode 11 to the cathode 16. Therefore, the light-emitting element 1 may include the substrate 10 as a support.

[0031] The substrate 10 may be a rigid inorganic substrate such as a glass substrate, or a flexible substrate mainly composed of a resin such as polyimide. The substrate 10 may also be provided with TFTs (thin-film transistors), capacitive elements, etc. (not shown).

[0032] The anode 11 is an electrode that supplies holes to the EML 14 when a voltage is applied. The cathode 16 is an electrode that supplies electrons to the EML 14 when a voltage is applied. The anode 11 and cathode 16 each contain a conductive material and are connected to a power supply (not shown) so that a voltage is applied between them.

[0033] At least one of the anode 11 and cathode 16 is a translucent electrode. Alternatively, either the anode 11 or cathode 16 may be a so-called reflective electrode that is light-reflecting. The light-emitting element 1 can extract light from the translucent electrode side.

[0034] If the light-emitting element 1 is a top-emission type light-emitting element that emits light from the upper electrode side, a translucent electrode is used for the upper electrode and a reflective electrode is used for the lower electrode. On the other hand, if the light-emitting element 1 is a bottom-emission type light-emitting element that emits light from the lower electrode side, a translucent electrode is used for the lower electrode and a reflective electrode is used for the lower electrode.

[0035] Translucent electrodes are formed from conductive translucent materials such as ITO (indium tin oxide) and IZO (indium zinc oxide).

[0036] On the other hand, the reflective electrode is formed from a conductive, light-reflective material such as a metal like Al (aluminum) or Ag (silver), or an alloy containing these metals. Alternatively, a reflective electrode may be formed by laminating a layer made of the above-mentioned translucent material with a layer made of the above-mentioned light-reflective material.

[0037] HIL12 is a charge implantation layer that includes a hole-transporting HIL material (hole-transporting material) as a functional material, and has a hole-injection function that enhances the efficiency of hole injection from anode 11 to HTL13. Examples of the above HIL material include a composite of poly(3,4-ethylenedioxythiophene) (PEDOT) and polystyrene sulfonic acid (PSS) (PEDOT:PSS).

[0038] HTL13 is a charge transport layer that contains a hole transport material (HTL material) with hole transport properties as a functional material, and has a hole transport function that enhances the efficiency of hole transport to EML14. The above HTL material may be an organic hole transport material such as poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-(4,4'-(N-4-sec-butylphenyl))diphenylamine)](TFB), poly(4-butyltriphenylamine)(p-TPD), poly(9-vinylcarbazole)(PVK), [9,9'-[1,2-phenylenebis(methylene)]bis[N3,N3,N6,N6-tetrakis(4-methoxyphenyl)-9H-carbazole-3,6-diamine](V886), 7,7'-bi[1,4]benzoxazino[2,3,4-kl]phenoxazine(HN-D1), or an inorganic hole transport material such as nanoparticles of p-type oxide semiconductors such as nickel oxide (NiO). Among these, p-type oxide semiconductor nanoparticles are preferred as the HTL material due to their high chemical stability, and NiO nanoparticles are particularly preferred from the viewpoint of hole transport properties and energy levels.

[0039] In this disclosure, "nanoparticles" means dots (particles) consisting of particles with a maximum width of less than 1000 nm. The shape of the nanoparticles is not particularly restricted and is not limited to a spherical three-dimensional shape (circular cross-sectional shape), as long as it satisfies the above maximum width. For example, it may be a polygonal cross-sectional shape, a rod-shaped three-dimensional shape, a branch-shaped three-dimensional shape, a three-dimensional shape with irregularities on the surface, or a combination thereof.

[0040] ETL15 is a charge transport layer that contains an ETL material (electron transport material) having electron transport properties as a functional material, and has an electron transport function that enhances the efficiency of electron transport to EML14. Examples of the above ETL material include nanoparticles of n-type oxide semiconductors and nanoparticles of organometallic complexes. Examples of n-type oxide semiconductors include n-type metal oxides such as zinc oxide (ZnO) and magnesium zinc oxide (ZnMgO). Examples of organometallic complexes include tris(8-quinolinol)aluminum complex (Alq3). The above ETL material may also be an organic material such as (2,2',2''-(1,3,5-benzintriyl)-tris(1-phenyl-1-H-benzimidazole) (TPBi) or basocuproine (BCP).

[0041] In particular, oxygen adsorption to n-type oxide semiconductors results in defect-type adsorption, creating an electron-deficient layer on the surface of the oxide semiconductor. Therefore, when a large amount of oxygen is adsorbed onto nanoparticles of n-type oxide semiconductors such as ZnO and ZnMgO, the oxygen traps electrons, altering the properties as an ETL (Electron Transducer). Specifically, the adsorbed oxygen consumes some of the electrons flowing through the nanoparticles of the oxide semiconductor, reducing the electron supply. Therefore, if the carrier balance of the light-emitting element 1 is electron-rich, electron injection into the EML 14 can be suppressed, and the carrier balance can be adjusted. For this reason, using nanoparticles of n-type oxide semiconductors as the ETL material improves the luminescence characteristics and enhances the external quantum efficiency (EQE). Consequently, nanoparticles of n-type oxide semiconductors are preferred as the ETL material. Among these, the ETL material preferably contains at least one of ZnO nanoparticles and ZnMgO nanoparticles due to its high chemical stability, and particularly preferably contains ZnMgO nanoparticles from the viewpoint of electron transport and energy levels.

[0042] EML14 is a layer that contains a light-emitting material as a functional material, and the light-emitting material is a nano-sized QD21 corresponding to the emission color, which emits light through the recombination of holes transported from the anode 11 and electrons transported from the cathode 16.

[0043] QD21 is a dot composed of nanoparticles with a maximum width of 100 nm or less. As mentioned above, QDs are generally referred to as semiconductor nanoparticles because their composition is derived from semiconductor materials. QDs are also sometimes referred to as nanocrystals because their structure has, for example, a specific crystalline structure.

[0044] The shape of QD21 is not particularly restricted and is not limited to a spherical solid shape (circular cross-sectional shape), as long as it satisfies the above-mentioned maximum width. For example, it may be a polygonal cross-sectional shape, a rod-shaped solid shape, a branch-shaped solid shape, a solid shape with irregularities on its surface, or a combination thereof.

[0045] QD21 may be a core type, or it may be a core-shell type or core-multi-shell type, including a core and a shell. If QD21 includes a shell, the core is in the center, and the shell may be provided on the surface of the core. It is desirable that the shell covers the entire core, but it is not necessary for the shell to completely cover the core. Furthermore, QD21 may be a two-component core type, a three-component core type, or a four-component core type. In addition, QD21 may contain doped nanoparticles or have a structure with a compositional gradient.

[0046] The core can be made of materials such as Si, Ge, CdSe, CdS, CdTe, InP, GaP, InN, ZnSe, ZnS, ZnTe, CdSeTe, GaInP, ZnSeTe, etc. The shell can be made of materials such as CdS, ZnS, CdSSe, CdTeSe, CdSTe, ZnSSe, ZnSTe, ZnTeSe, AIP, etc.

[0047] QD21's emission wavelength can be varied depending on the particle size, composition, etc. QD21 is a QD that emits visible light, and by appropriately adjusting the particle size and composition of QD21, for example, red light, green light, and blue light can be realized.

[0048] QD is commercially available, and commercially available QDs are generally provided in the form of a quantum dot dispersion containing organic ligands. Hereinafter, regardless of whether or not it contains an organic ligand, a quantum dot dispersion containing quantum dots (QDs) may be referred to as a "QD dispersion". Further, QDs can be synthesized by any method. For example, a wet method is used for the synthesis of QDs, and the particle size of QDs is controlled by coordinating an organic ligand on the surface of the QDs. The organic ligand is used as a dispersant for improving the dispersibility of QDs in the QD dispersion, and is also used for improving the surface stability and storage stability of QDs.

[0049] Therefore, an organic ligand may be coordinated to QD21. Further, QD21 may have a desired organic ligand or inorganic ligand coordinated thereto that has been exchanged by ligand exchange or the like. The types of these ligands are not particularly limited, and various known ligands can be mentioned.

[0050] As described above, the light-emitting element 1 shown in FIG. 1 has 1 an O2 scavenger 31 (singlet oxygen scavenger). Therefore, EML14 contains QD21 and 1 an O2 scavenger 31.

[0051] 1 The O2 scavenger 31 does not consume and remove oxygen in the system but rather deactivates it, deactivating excited state 1 O2 and returning it to the ground state triplet oxygen ( 3 O2) to calm it down.

[0052] As described above, 1 a non-protic 1 O2 scavenger is used for the O2 scavenger 31. A non-protic 1 O2 scavenger refers to an O2 scavenger that does not contain a hetero element such as an oxygen element or a nitrogen element, or, even if it contains a hetero element, the hydrogen element is not directly bonded to the hetero element. 1 O2 scavenger is indicated. 1 A non-protic 1The reasons for using an O2 scavenger are as follows:

[0053] aprotic 1 Unlike O2 scavengers, proton systems have a structure in which hydrogen elements are directly bonded to heteroatoms. 1 Regardless of the amount used, the O2 scavenging agent is a proton system 1 At the point when the O2 scavenger is added, the proton system 1 The O2 scavenger coordinates to QD21.

[0054] Therefore, proton system 1 Even if only a small amount is added, the O2 scavenging agent will coordinate to QD21 at the time of addition. However, the proton system 1 Depending on the amount of O2 scavenger used, the proton system relative to QD21 1 The coordination ratio between the O2 scavenger and the ligand that was previously coordinated to QD21 changes. And the proton system 1 The greater the coordination amount of the O2 scavenger, the higher the risk of degraded luminescence properties and adverse effects on material stability. In particular, proton systems consisting of bifunctional molecules containing two or more primary and secondary amino groups, which are coordinating functional groups, are prone to this. 1 When an O2 scavenger is coordinated to QD21, the dispersibility of QD21 is significantly reduced. 1 When an O2 scavenger is coordinated, the dispersibility of QD21 changes, which degrades the luminescence characteristics and reliability of the light-emitting element 1.

[0055] However, aprotic 1 As described above, the O2 scavenger does not contain heteroatoms such as oxygen or nitrogen, or if it does contain heteroatoms, hydrogen is not directly bonded to the heteroatoms and it does not have coordinating functional groups that can coordinate to QD21. Note that coordinating functional groups are also called ligand coordinating groups.

[0056] The above-mentioned coordinating functional group can be any at least one selected from the group consisting of a thiol group, a primary amino group, a secondary amino group, a carboxyl group, a primary phosphone group, a secondary phosphone group, a primary phosphine group, a secondary phosphine group, a primary phosphine oxide group, and a secondary phosphine oxide group.

[0057] 1 The O2 scavenger 31, as such, does not possess coordinating functional groups, does not react with QD21, and therefore does not act as a ligand. For this reason, 1 The O2 scavenger 31 does not coordinate to QD21 and therefore does not pose a risk of adversely affecting the dispersibility or luminescence properties of QD21.

[0058] Here, "coordination" refers to the ligand binding to the surface of QD21. Therefore, 1 The fact that the O2 scavenging agent 31 does not coordinate to QD21 means that 1 This demonstrates that the O2 scavenging agent 31 does not bind to the surface of QD21.

[0059] Included in the functional layer 1 The O2 scavenging agent 31 can be identified, for example, by analyzing the elements and molecular structure contained in each location using TOF-SIMS (time-of-flight secondary ion mass spectrometry).

[0060] the above 1 For example, the O2 scavenger 31 is an energy-absorbing aprotic 1 O2 scavengers (energy-absorbing aprotic singlet oxygen scavengers), oxidizable aprotic 1 Examples include O2 scavengers (oxidizable aprotic singlet oxygen scavengers).

[0061] Energy-absorbing aprotic 1 What is an O2 scavenger? 1 It is an aprotic singlet oxygen scavenger that absorbs the energy of O2 and converts it back to triplet oxygen. Hereafter, triplet oxygen will be referred to as " 3 It is written as "O2". Energy-absorbing aprotic singlet oxygen scavengers are 1 Absorbing the energy of O2 3By returning to O2, 1 The O2 is repeatedly erased.

[0062] Oxidizable aprotic 1 O2 scavengers are oxidized themselves. 1 O2 3 Aprotonated, returning to O2 1 It is an O2 scavenger. It is an oxidizable aprotic type. 1 O2 scavengers oxidize themselves 1 By eliminating O2, 1 It functions as a vanguard against the oxidation of QD21 by O2 attack, and loses that function after oxidation.

[0063] the above 1 O2 scavenger 31 is an energy-absorbing aprotic 1 O2 scavenger and oxidizable aprotic 1 Preferably contains at least one of the O2 scavengers, and is an energy-absorbing aprotic type 1 It is more preferable that the product contains an O2 scavenger.

[0064] the above 1 Examples of the O2 scavenger 31 include at least one compound selected from the group consisting of tertiary amines, carotenoids, ethylenic compounds, naphthalene and its derivatives, and anthracene and its derivatives. The light-emitting element 1 is as described above. 1 As the O2 scavenger 31, these examples 1 It is desirable to include at least one selected from the group consisting of O2 scavenging agents.

[0065] aprotic elements containing heteroatoms that are not directly bonded to hydrogen. 1 O2 scavengers are energy-absorbing aprotic 1 It functions as an O2 scavenger. It is aprotic and does not contain heteroatoms. 1 O2 scavengers are mainly oxidizable aprotic 1 It is used as an O2 scavenger, but is an energy-absorbing aprotic type. 1 It is sometimes used as an O2 scavenging agent.

[0066] Energy-absorbing aprotic 1 A non-protic element containing heteroatoms that are not directly bonded to hydrogen, used as an O2 scavenger. 1 Examples of O2 scavenging agents include tertiary amines, ethylenic compounds containing heteroatoms, naphthalenes (naphthalene derivatives) containing heteroatoms, and anthracenes (anthracene derivatives) containing heteroatoms.

[0067] the above 1 Monomers are used in the O2 scavenging agent 31. Monomers are compounds with a molecular weight of 1000 or less. Polymers have a large number of repetitions of a unit structure (monomer) and generally have around 1000 or more atoms, or are polymerized to a molecular weight of 10000 or more. Oligomers, on the other hand, have a small number of repetitions of a unit structure (monomer) and generally have a molecular weight of 1000 to 10000.

[0068] the above 1 The O2 scavenger 31 may contain oligomers or polymers, but may be polymerized or oligomerized. 1 O2 scavengers have larger molecules. Also, polymers are basically highly insulating, which may reduce their luminescence properties. For this reason, 1 The O2 scavenger 31 is preferably a monomer. 1 By using a monomer in the O2 scavenger 31, the gaps between adjacent QD21 can be filled. 1 To effectively suppress attacks on QD21 by O2, 1 O2 can be eliminated.

[0069] therefore, 1 For the O2 scavenger 31, monomers are preferably used for tertiary amines, ethylenic compounds containing heteroatoms, naphthalenes (naphthalene derivatives) containing heteroatoms, and anthracenes (anthracene derivatives) containing heteroatoms.

[0070] Examples of the above-mentioned tertiary amines include triethylamine, N,N-dimethylaniline, 1,4-diazabicyclo[2.2.2]octane (DABCO), and 1-ethylimidazole. Examples of ethylenic compounds containing heteroatoms include 1,2-diethoxyethene.

[0071] Examples of naphthalenes containing heteroatoms include naphthalene derivatives in which at least one of the carbon elements constituting the naphthalene ring, or at least one of the hydrogen elements bonded to the naphthalene ring, is substituted with a heteroatom, and the hydrogen element is not directly bonded to the heteroatom.

[0072] Examples of anthracenes containing heteroatoms include anthracene derivatives in which at least one of the carbon elements constituting the anthracene ring, or at least one of the hydrogen elements bonded to the anthracene ring, is substituted with a heteroatom, and the heteroatom is not directly bonded to a hydrogen element. Examples of such anthracenes include dimethoxyanthracene and 9,10-bis(4-methoxyphenyl)anthracene.

[0073] Oxidizable aprotic 1 A non-heteroatomic aprotic O2 scavenger used 1 Examples of O2 scavenging agents include ethylenic compounds that do not contain heteroatoms, naphthalenes that do not contain heteroatoms (naphthalene, naphthalene derivatives), anthracenes that do not contain heteroatoms (anthracene, anthracene derivatives), and 1,2,3,4-tetraphenyl-1,3-cyclopentadiene, which is a cyclopentadiene that does not contain heteroatoms and is substituted only with a phenyl group.

[0074] Examples of ethylenic compounds that do not contain heteroatoms include tetramethylethylene and cyclopentene.

[0075] Examples of naphthalenes that do not contain heteroatoms include naphthalenes in which at least one of the carbon elements constituting the naphthalene ring, or at least one of the hydrogen elements bonded to the naphthalene ring, may be substituted with an element other than a heteroatom. Examples of such naphthalenes include naphthalene and dimethylnaphthalene.

[0076] Anthracenes that do not contain heteroatoms include anthracenes in which at least one of the carbon elements constituting the anthracene ring, or at least one of the hydrogen elements bonded to the anthracene ring, may be substituted with an element other than a heteroatom. Examples of such anthracenes include anthracene.

[0077] Furthermore, the above 1 The O2 scavenger 31 may be a carotenoid as described above. Examples of such carotenoids include aprotic carotenoids such as lycopene, α-carotene, and β-carotene. These exemplified carotenoids are aprotic carotenoids that do not contain heteroatoms. 1 These carotenoids are O2 scavengers. Due to a combination of factors, under certain conditions, they are oxidizable and aprotic. 1 It is sometimes used as an O2 scavenger, and also as an energy-absorbing aprotic agent. 1 It is sometimes used as an O2 scavenging agent.

[0078] 1 These aprotic 1 The O2 scavenging agent may be used alone, or two or more types may be mixed together as appropriate. 1 As for the O2 scavenging agent 31, these aprotic 1 Among the O2 scavengers, tertiary amines are preferred. Furthermore, among these tertiary amines, at least one selected from the group consisting of 1,4-diazabicyclo[2.2.2]octane, triethylamine, and N,N-dimethylaniline is more preferred.

[0079] Therefore, the light-emitting element 1 is 1 It is preferable that the O2 scavenger 31 contains a tertiary amine. Furthermore, it is more preferable that the light-emitting element 1 contains at least one selected from the group consisting of 1,4-diazabicyclo[2.2.2]octane, triethylamine, and N,N-dimethylaniline as the tertiary amine.

[0080] However, the use in this embodiment 1 The O2 scavenger 31 is aprotic as exemplified above. 1 This is not limited to O2 scavenging agents. 1 The O2 scavenging agent 31 may be, for example, furans such as furans and their derivatives.

[0081] In this embodiment, the ratio of 1 part by weight of QD21 in EML14 1 The content ratio of the O2 scavenger 31 is preferably within the range of 0.001 parts by weight or more and 1 part by weight or less. In EML14, relative to 1 part by weight of QD21 1 If the content ratio of O2 scavenger 31 exceeds 1 part by weight, the film quality of EML14 may deteriorate. Also, a decrease in the proportion of QD21 contained in EML14 may significantly reduce the luminescence properties. On the other hand, in EML14, the ratio of 1 part by weight of QD21 1 If the content ratio of the O2 scavenging agent 31 is less than 0.001 parts by weight, 1 There is a risk that the degradation of QD21 due to O2 may not be sufficiently suppressed.

[0082] (By the way of the light-emitting element 1) The following describes a method for manufacturing a light-emitting element according to one aspect of this disclosure, using the method for manufacturing the light-emitting element 1 shown in Figure 1 as an example.

[0083] Figure 2 is a flowchart showing the manufacturing method of the light-emitting element 1 shown in Figure 1.

[0084] In the manufacturing method of the light-emitting element 1 shown in FIG. 1, as shown in FIG. 2, first, an anode 11 is formed on a substrate 10 (step S1, anode formation step). Next, a functional layer formation step of forming a plurality of functional layers is performed on the anode 11. The functional layer formation step according to the present embodiment includes the following steps S2 to step S5 and step S11.

[0085] In the present embodiment, as the functional layer formation step, after step S1, first, a HIL 12 is formed on the anode 11 (step S2, HIL formation step). Next, a HTL 13 is formed (step S3, HTL formation step). The method up to this point is the same as the general manufacturing method of QLED.

[0086] On the other hand, a QD dispersion liquid (quantum dot dispersion liquid) containing QD 21 and 1 an O2 scavenger 31 and a solvent is prepared (manufactured) (step S11, QD dispersion liquid preparation step).

[0087] As the above solvent, for example, a non-polar solvent such as hexane is used. The concentration of QD 21 in the above QD dispersion liquid may be appropriately set according to the design value of the layer thickness of the EML 14 and the like, and is not particularly limited.

[0088] In the above QD dispersion liquid, for 1 part by weight of QD 21 1 the content ratio of the O2 scavenger 31 is set so that the content ratio of the O2 scavenger 31 with respect to 1 part by weight of QD 21 in the EML 14 is within the range of 0.001 part by weight or more and 1 part by weight or less. For this reason, in the above QD dispersion liquid, for 1 part by weight of QD 21 1 the content ratio of the O2 scavenger 31 is set, for example, within the range of 0.001 part by weight or more and 1 part by weight or less. When the content ratio of the O2 scavenger 31 with respect to 1 part by weight of QD 21 in the above QD dispersion liquid exceeds 1 part by weight, the film quality of the formed EML 14 may deteriorate. Also, the proportion of QD 21 contained in the formed EML 14 may decrease, and the light-emitting characteristics may be significantly reduced. On the other hand, in the above QD dispersion liquid, for 1 part by weight of QD 21 1 the content ratio of the O2 scavenger 31 is set, for example, within the range of 0.001 part by weight or more and 1 part by weight or less. When the content ratio of the O2 scavenger 31 with respect to 1 part by weight of QD 21 in the above QD dispersion liquid exceeds 1 part by weight, the film quality of the formed EML 14 may deteriorate. Also, the proportion of QD 21 contained in the formed EML 14 may decrease, and the light-emitting characteristics may be significantly reduced. On the other hand, in the above QD dispersion liquid, for 1 part by weight of QD 21 1 the content ratio of the O2 scavenger 31 is set, for example, within the range of 0.001 part by weight or more and 1 part by weight or less. When the content ratio of the O2 scavenger 31 with respect to 1 part by weight of QD 21 in the above QD dispersion liquid exceeds 1 part by weight, the film quality of the formed EML 14 may deteriorate. Also, the proportion of QD 21 contained in the formed EML 14 may decrease, and the light-emitting characteristics may be significantly reduced. On the other hand, in the above QD dispersion liquid, for 1 part by weight of QD 21 1If the content ratio of the O2 scavenging agent 31 is less than 0.001 parts by weight, 1 There is a risk that the degradation of QD21 due to O2 may not be sufficiently suppressed.

[0089] Next, EML14 is formed using the above QD dispersion (Step S4, EML formation step). Note that Step S11 may be performed before Step S4.

[0090] In step S4, the QD dispersion is first applied to the HTL13, which will serve as the base layer for the EML14 (step S4a, QD dispersion application step). This forms a coating film of the QD dispersion. For example, spin coating can be used to apply the QD dispersion.

[0091] Next, the coating film is heated or otherwise removed to remove the solvent contained in the coating film (i.e., the applied QD dispersion) and the coating film is dried (step S4b, solvent removal step). This removes QD21 and 1 EML14 containing O2 scavenging agent 31 is formed.

[0092] Furthermore, a ligand may be coordinated to QD21, and the above-mentioned QD dispersion and EML14 may contain known ligands.

[0093] Next, the ETL 15 is formed (Step S5, ETL formation step). Then, the cathode 16 is formed (Step S6, cathode formation step). This forms the light-emitting element 1 shown in Figure 1.

[0094] Furthermore, the manufacturing method of the light-emitting element 1 is as follows: 1 Except for the addition of the O2 scavenging agent 31, the manufacturing method is the same as that of a typical QLED. The anode 11 and cathode 16 can be formed by, for example, vapor deposition, sputtering, or inkjet. In addition, each functional layer constituting the light-emitting element 1 can be formed by, for example, coating. For the formation of each functional layer, for example, spin coating, vacuum deposition, or inkjet can be used.

[0095] (Specific example of a method for manufacturing the light-emitting element 1) Next, an example of a manufacturing method for the light-emitting element 1 shown in Figure 1 is presented. As described above, the light-emitting element 1 shown in Figure 1 is manufactured, for example, by depositing the anode 11, HIL 12, HTL 13, EML 14, ETL 15, and cathode 16 on a substrate 10 in this order.

[0096] In this embodiment, as an example, an ITO layer was formed on a substrate 10 as the anode 11. Next, a PEDOT:PSS layer was formed as HIL12 by spin-coating a solution containing PEDOT:PSS onto the ITO layer and then evaporating the solvent by baking. Next, a TFB layer was formed as HTL13 by spin-coating a solution containing TFB onto the PEDOT:PSS layer and then evaporating the solvent by baking.

[0097] On the other hand, QD21, which has an InP / ZnS core / shell structure and a number-average particle size (diameter) of 10 nm, was dispersed in hexane as a solvent at a concentration of 6 mg / mL. Then, to the dispersion obtained therefrom, 1 As the O2 scavenging agent 31, DABCO was added to the hexane at a ratio of 5 mg / mL. This prepared a QD dispersion containing 5 mg of DABCO for every 6 mg of QD in 1 mL of hexane.

[0098] Next, the QD dispersion was spin-coated onto the TFB layer at a spin speed of 200 rpm for 30 seconds. Then, by baking at 80°C for 10 minutes to evaporate the hexane, an EML14 layer containing the QD and DABCO, for example, with a thickness of 20 nm, was formed on the TFB layer. Next, a dispersion containing ZnMgO nanoparticles was spin-coated onto the EML14, and the solvent was evaporated by baking to form a ZnMgO nanoparticle layer as ETL15. Then, an Al layer was formed on this ZnMgO nanoparticle layer as cathode 16.

[0099] (effect) As described above, QD21 functions as a photosensitizer. When QD21 is excited, energy is transferred from QD21 to 3 ground-state oxygen 1 O2, and 3 when the excited light is irradiated onto 3 O2 in the presence of the photosensitizer, 1 O2 is excited and 1 singlet oxygen 1 O2 is generated, and QD21 is oxidized. Inside the light-emitting device 1, there are oxygen in the atmosphere that has entered the light-emitting device 1, oxygen in the solvent that has remained in the light-emitting device 1, oxygen contained in the material, and the like.

[0100] However, according to the present embodiment, as described above, since EML14 1 contains an aprotic 1 O2 scavenger as the 1 O2 scavenger 31, the generated 3 singlet oxygen 1 O2 is returned to

[0101] ground-state oxygen

[0102] O2 and eliminated without adversely affecting the dispersibility and light-emitting characteristics of QD21. Therefore, according to the present embodiment, it is possible to suppress the deterioration due to the oxidation of QD21 without adversely affecting the dispersibility and light-emitting characteristics of QD21, and to provide the light-emitting device 1 having high luminous efficiency and reliability. 1 The

[0103] O2 scavenger 31 only deactivates the excited state of oxygen and does not remove oxygen. Therefore, according to the present embodiment, it is possible to suppress a decrease in the light-emitting characteristics of QD21 while allowing oxygen in the system to coexist with QD21.Furthermore, QD21 is also oxidized by exposure to air and solvents during the manufacturing process. For example, fluorescent lamps also function as excitation light. According to this embodiment, EML14 1 The inclusion of the O2 scavenger 31 means that after the formation of the light-emitting element 1, 1 In addition to protecting QD21 from O2, it also protects against the effects of the manufacturing process. 1 It can also protect QD21 from O2.

[0104] Furthermore, according to this embodiment, the QD dispersion is 1 By simply mixing in the O2 scavenger 31, the process itself remains unchanged. 1 An EML14 light-emitting layer containing the O2 scavenging agent 31 can be formed. Therefore, according to this embodiment, it is possible to use the existing equipment as is, and the above method can be easily introduced.

[0105] [Embodiment 2] A light-emitting element according to one aspect of the present disclosure may include an EML14 and a first functional layer as the at least one functional layer, as shown in Embodiment 1. In the light-emitting element according to this embodiment, the first functional layer is adjacent to the EML14 and contains an oxygen element-containing compound, and the EML14 is 1 The O2 scavenger 31 is contained in the portion of the EML14 that is closer to the first functional layer than to the center in the thickness direction of the EML14. 1 The density of the O2 scavenger 31 is greater in the portion of the EML 14 that is further from the first functional layer than in the center of the thickness direction. 1 The density may be higher than that of the O2 scavenging agent 31.

[0106] Furthermore, the above-mentioned light-emitting element is in EML14 1 The density of the O2 scavenger 31 may be higher in the thickness direction of the EML14, closer to the first functional layer. However, in this case, 1 The density distribution of the O2 scavenger 31 does not need to increase linearly (i.e., linearly and continuously) as it approaches the first functional layer; it may increase in steps. In this disclosure, in EML14 1The density of the O2 scavenger 31 is higher in the part closer to the first functional layer, which means that in EML14... 1 This indicates that the density of the O2 scavenger 31 may increase linearly in the thickness direction of the EML 14 as it approaches the first functional layer, or it may increase in a stepwise manner as it approaches the first functional layer.

[0107] In the following, we will explain using the case where the first functional layer is a carrier transport layer as an example, and also using the case where the light-emitting element has a conventional structure and the carrier transport layer as the first functional layer is ETL15 as an example.

[0108] Figure 3 is a schematic cross-sectional view showing an example of a light-emitting element 41 according to this embodiment.

[0109] As an example, the light-emitting element 41 shown in Figure 3, like the light-emitting element 1 shown in Embodiment 1, is equipped with an anode 11, HIL 12, HTL 13, EML 14, ETL 15, and cathode 16 in this order from the bottom layer. Also, like the light-emitting element 1, the ETL 15 contains nanoparticles such as n-type metal oxides like ZnO and ZnMgO, or organometallic complexes containing oxygen, such as Alq3, as an ETL material (oxygen-containing compound) containing the element of oxygen. 1 The O2 scavenging agent 31 is mixed into EML14.

[0110] However, as shown in Figure 3, the light-emitting element 41 is located in the part of the EML14 that is closer to the ETL15 than to the center in the thickness direction of the EML14. 1 The density of the O2 scavenger 31 is greater in the portion of the EML 14 that is further from the ETL 15 than in the center of the thickness direction. 1 Higher than the density of the O2 scavenger 31, more specifically, in EML14 1 The density of the O2 scavenging agent 31 is higher in areas closer to the ETL 15. The light-emitting element 41 differs from the light-emitting element 1 in this respect.

[0111] (Method of manufacturing the luminescent element 41) Figure 4 is a flowchart showing the manufacturing method of the light-emitting element 41 shown in Figure 3.

[0112] In the manufacturing method of the light-emitting element 41 shown in Figure 3, steps S1 (anodic formation step) to S3 (HTL formation step) are performed in the same manner as the manufacturing method of the light-emitting element 1 described above, as shown in Figure 4. Subsequently, in this embodiment, an EML 14 containing QD21 is formed using a QD dispersion containing QD21 and a solvent (step S4, EML formation step). As with Embodiment 1, a non-polar solvent such as hexane is used as the solvent. The concentration of QD21 in the QD dispersion can be appropriately set according to the design value of the layer thickness of the EML 14, etc., and is not particularly limited.

[0113] In this embodiment, 1 The above QD dispersion, which does not contain an O2 scavenger, is applied to the HTL13 to form a coating of the QD dispersion. Then, the solvent contained in the coating is removed by heating or other means. This allows, 1 EML14 without an O2 scavenger is first formed. Note that, in this embodiment as well, the preparation of the QD dispersion can be done before step S4. The method up to this point is the same as that of a general QLED manufacturing method.

[0114] On the other hand, in this embodiment, as shown in Figure 4, 1 The O2 scavenger 31 and a solvent are included. 1 Prepare (manufacture) the O2 scavenging agent solution (step S21, 1 (O2 scavenger solution preparation step). For example, amphoteric solvents such as isopropyl alcohol (IPA) and ethanol can be used as the solvent. 1 In O2 scavenging solution 1 The concentration of O2 scavenger 31 in EML14 1 The density distribution of the O2 scavenger 31 can be appropriately set according to the layer thickness of the EML 14, etc., so that it becomes the desired density distribution, and is not particularly limited.

[0115] Next, the above EML14 1 The O2 scavenger solution is supplied, 1 The O2 scavenging agent solution is permeated into the EML14 (step S31). 1(O2 scavenging agent solution supply step). Note that step S21 may be performed before step S31.

[0116] In step S31, first, 1 On EML14 that does not contain an O2 scavenger, the above 1 The O2 scavenging agent solution is added dropwise, 1 The O2 scavenging agent solution is applied to the EML14. This allows the O2 to be absorbed into the EML14. 1 Permeate with the O2 scavenging agent solution. 1 For applying the O2 scavenging agent solution, for example, spin coating can be used.

[0117] Next, the above 1 By heating the EML14 coated with the O2 scavenging agent solution, etc. 1 The solvent contained in the O2 scavenging agent solution is removed (step S32, solvent removal step). This removes QD21 and 1 EML14 containing O2 scavenging agent 31 is formed.

[0118] Subsequently, steps S5 (ETL formation step) and S6 (cathode formation step) are performed in the same manner as in the manufacturing method of the light-emitting element 1. This forms the light-emitting element 41 shown in Figure 3.

[0119] The method for manufacturing the light-emitting element 41 is the same as the method for manufacturing the light-emitting element 1, except for the points mentioned above.

[0120] (Specific example of a method for manufacturing the light-emitting element 41) Next, an example of a manufacturing method for the light-emitting element 41 shown in Figure 3 is presented.

[0121] In this embodiment, as an example, an ITO layer was formed as the anode 11 on a 25 mm square substrate 10 as a support. Next, a PEDOT:PSS layer was formed as HIL 12 by spin-coating a solution containing PEDOT:PSS onto the ITO layer and then evaporating the solvent by baking. Next, a TFB layer was formed as HTL 13 by spin-coating a solution containing TFB onto the PEDOT:PSS layer and then evaporating the solvent by baking.

[0122] On the other hand, QD21, which has an InP / ZnS core / shell structure and a number-average particle size (diameter) of 10 nm, was dispersed in hexane as a solvent at a concentration of 13 mg / mL. This prepared a QD dispersion containing the above QD and solvent.

[0123] Next, the QD dispersion was spin-coated onto the TFB layer at a spin speed of 200 rpm for 30 seconds. Then, by baking at 80°C for 10 minutes to evaporate the hexane, a QD layer containing the QDs, for example with a thickness of 20 nm, was formed on the TFB layer as EML14.

[0124] on the other hand, 1 DABCO, used as the O2 scavenging agent 31, was dispersed in IPA as a solvent to a concentration of 20 mg / mL. This resulted in... 1 A 20 mg / mL concentration DABCO-IPA solution was prepared as the O2 scavenging agent solution.

[0125] Next, 200 μL of the DABCO-IPA solution was dropped onto the QD layer formed on the 25 mm square substrate 10 as described above, and after 30 seconds, the DABCO-IPA solution was spin-coated at a spin speed of 3000 rpm for 60 seconds.

[0126] Furthermore, immediately after starting the spin coating process, IPA was added dropwise as a rinse solution, 200 μL at a time, three times (a total of 600 μL). This washed the QD layer and removed excess DABCO.

[0127] Then, by baking at 80°C for 10 minutes to evaporate the IPA, QD21 and 1 EML14 containing O2 scavenging agent 31 was formed.

[0128] Next, a dispersion containing ZnMgO nanoparticles was spin-coated onto the QD layer, and then the solvent was evaporated by baking to form a ZnMgO nanoparticle layer as ETL15. Then, an Al layer was formed on this ZnMgO nanoparticle layer as cathode16.

[0129] DABCO penetrated the QD layer and was mixed in with it. Although some remained on the surface of the QD layer, it did not form a DABCO layer on top of the QD layer, and there was virtually no increase in the thickness of the laminate due to DABCO.

[0130] Furthermore, the added DABCO remained in the QD layer with a density distribution, and the density of DABCO on the upper side of the QD layer (towards the ZnMgO nanoparticle layer) was higher than the density of DABCO on the lower side, meaning that the density of DABCO was higher towards the upper part of the QD layer. Here, "upper side" refers to the part of the QD layer above the center in the thickness direction of the QD layer (closer to the ZnMgO nanoparticle layer), and "lower side" refers to the part of the QD layer below the center in the thickness direction of the QD layer (further from the ZnMgO nanoparticle layer).

[0131] (effect) As described above, the light-emitting element 41 shown in Figure 3 has a first functional layer adjacent to the EML14, for example, ETL15, which contains an oxygen-containing compound, and the EML14 is 1 It contains an O2 scavenging agent 31. And, in the EML14, the portion closer to the ETL15 than the center in the thickness direction of the EML14 1 The density of the O2 scavenger 31 is greater in the portion of the EML 14 that is further from the ETL 15 than in the center of the thickness direction. 1 It is higher than the density of the O2 scavenger 31. More specifically, in EML14 1 The density of the O2 scavenging agent 31 is higher in the thickness direction of the EML14, particularly in areas closer to the EML14.

[0132] Therefore, according to this embodiment, in the portion of EML14 close to the EML14 containing the oxygen element compound, 1 It can capture O2.

[0133] In this embodiment as well, in EML14, relative to 1 part by weight of QD21 1 For the same reasons as in Embodiment 1, the content ratio of the O2 scavenging agent 31 is preferably within the range of 0.001 parts by weight or more and 1 part by weight or less.

[0134] However, according to this embodiment, 1 Compared to the case where the O2 scavenging agent 31 is uniformly mixed throughout the EML14, 1 The amount of O2 scavenging agent 31 used can be reduced.

[0135] In EML14 1 As the proportion of O2 scavenging agent 31 increases, the effect on the film formation properties and surface roughness of EML14 becomes greater. Therefore, 1 If the amount of O2 scavenging agent 31 used is too large, it may adversely affect the luminescence. However, according to this embodiment, as described above... 1 Since the amount of O2 scavenging agent 31 used can be reduced, 1 This reduces the risk of the O2 scavenging agent 31 having the adverse effects on the EML14 as described above. Furthermore, it reduces material costs and lowers the overall manufacturing cost of the light-emitting element.

[0136] In this embodiment, the ratio of 1 part by weight of QD21 in EML14 1 The content ratio of O2 scavenger 31 is EML14. 1 As a result of supplying the O2 scavenging agent solution, it permeated EML14. 1 This is the content ratio of O2 scavenger 31 to QD21. In this embodiment, as described above, washing is performed with a rinse solution, so in this case, the EML14 is penetrated. 1 The content ratio of the O2 scavenging agent 31 is such that it remains in EML14 after removal with the rinsing solution. 1 This shows the content ratio of the O2 scavenging agent 31.

[0137] According to this embodiment, as described above, on EML14, 1 The O2 scavenger 31 and a solvent are included. 1By supplying the O2 scavenging agent solution and allowing the solution to permeate the EML14, within the EML14, 1 The density distribution of the O2 scavenger 31 can be adjusted.

[0138] In this embodiment, as described above, the QD dispersion is 1 By adding O2 scavenger 31, QD21 and 1 Instead of forming a mixed film with the O2 scavenger 31, 1 An EML14 without the O2 scavenger 31 is formed, and the EML14 1 The O2 scavenging agent solution is supplied and allowed to permeate. Therefore, EML14 and 1 The longer the contact time with the O2 scavenging solution, the better. 1 The O2 scavenging agent solution can be permeated into the EML14. 1 If the O2 scavenging agent solution is supplied to EML14 and then immediately removed, 1 The O2 scavenging agent solution can be supplied only to the vicinity of the surface of EML14. In this way, 1 The density distribution of the O2 scavenger 31 can be intentionally adjusted.

[0139] Also, 1 The density distribution of the O2 scavenger 31 is, for example, 1 The viscosity of the O2 scavenging agent solution can also be adjusted. Therefore, 1 The density distribution of the O2 scavenger 31 depends on the solvent used and 1 It can be changed depending on the type of O2 scavenger 31. 1 In O2 scavenging solution 1 The concentration of the O2 scavenging agent 31 can also be changed.

[0140] Also, 1 The density distribution of the O2 scavenger 31 is, for example, 1 The O2 scavenger solution 1 O2 scavenging solution 1 It can also be adjusted by the wettability of the layer to which the O2 scavenging agent solution is supplied. In this embodiment, 1 The density distribution of the O2 scavenger 31 is: 1The wettability of EML14 to the O2 scavenging agent solution can also be adjusted.

[0141] 1 O2 scavenger solution supplied to the layer 1 When the O2 scavenging agent solution is added dropwise, 1 In the O2 scavenger solution supplied layer 1 Wettability of O2 scavenging agent solution ( 1 O2 scavenger solution supplied layer and 1 (Polarity-nonpolarity relationship with the O2 scavenger solution) 1 In the O2 scavenger solution supplied layer 1 The way the O2 scavenging agent solutions wet (affinity) differs. 1 In the O2 scavenger solution supplied layer 1 The wettability of the O2 scavenging agent solution depends not only on the affinity between the components, but also on the affinity between the components. 1 It also varies depending on the shape of the layer to which the O2 scavenging agent solution is supplied (for example, the size, shape, and number of irregularities). If the above wettability is poor, 1 O2 scavenger solution within the supplied layer 1 The O2 scavenging agent solution becomes less permeable, and an uneven distribution of density is more likely to occur. On the other hand, if the wettability is good, 1 O2 scavenger solution within the supplied layer 1 The O2 scavenging agent solution penetrates more easily, making it less likely for density distribution to occur, and resulting in a more uniform density distribution. 1 The wettability of the O2 scavenging agent solution-supplied layer depends, for example, on the polarity of the ligand and the length of the ligand chain. 1 The particle size and shape of nanoparticles such as QD21 contained in the O2 scavenging solution supply layer can also be varied.

[0142] Also, 1 The density distribution of the O2 scavenger 31 is, for example, 1 The solution can also be adjusted by the boiling point of the solvent used in the O2 scavenging agent solution. While it is also affected by the processing environment, solvents generally volatilize more easily the lower their boiling point. Therefore, 1 If a solvent with a low boiling point is used as the solvent for the O2 scavenging agent solution, 1 O2 scavenging agent solution 1 The penetration depth of the O2 scavenging agent solution into the supplied layer becomes shallower, making it easier for unevenness in the density distribution to occur. 1If a solvent with a high boiling point is used as the solvent for the O2 scavenging agent solution, the solvent will not volatilize easily. 1 O2 scavenging agent solution 1 The depth to which the O2 scavenging solution penetrates into the supplied layer increases.

[0143] Also, 1 The density distribution of the O2 scavenger 31 can also be adjusted, for example, by the processing environment (process environment). In step S32 (solvent removal step), the applied 1 When removing the solvent contained in the O2 scavenging agent solution, removing (drying) the solvent under reduced pressure or a dry environment accelerates the volatilization of the solvent. Therefore, performing step S32 under such conditions tends to result in an uneven density distribution. Here, "dry environment" refers to a situation where there is little solvent vapor, not limited to water.

[0144] Also, 1 The density distribution of the O2 scavenger 31 is: 1 The temperature of the O2 scavenging agent solution and the temperature of the processing environment can also be adjusted. Generally, the higher the temperature of the solution used and the processing environment, the more the solvent volatilizes, which tends to cause an uneven distribution of the density.

[0145] Furthermore, if the ambient atmosphere is circulated and ventilated during processing, solvent volatilization is accelerated, which can easily lead to uneven density distribution. Therefore, 1 The density distribution of the O2 scavenging agent 31 can also be adjusted by the processing method.

[0146] Thus, 1 The density distribution of the O2 scavenger 31 can be adjusted by various methods, and by combining the conditions described above, it is possible to adjust it to any desired density distribution. 1 As mentioned above, the density distribution of the O2 scavenger 31 does not necessarily need to change linearly.

[0147] (modified version) As described above, Figures 3 and 4 illustrate the case where the light-emitting element 41 has a conventional structure and the first functional layer is ETL 15. However, this embodiment is not limited to this. The light-emitting element 41 may have an inverted structure, and the first functional layer may be HTL 13. HTL 13 contains an oxygen element-containing compound such as nanoparticles of a p-type oxide semiconductor such as NiO, and in the portion of EML 14 closer to HTL 13 than the center in the thickness direction of EML 14 1 The density of the O2 scavenger 31 is determined in the portion of the EML14 that is further from the HTL13 than the center in the thickness direction. 1 By making the density higher than that of the O2 scavenger 31, the same effect as described above can be obtained. In this case, in EML14 1 The density of the O2 scavenger 31 may be higher in the part closer to HTL13. Thus, even when the first functional layer is HTL13, in EML14 1 The density distribution of the O2 scavenger 31 does not need to increase linearly the closer it is to the first functional layer; it can increase in steps.

[0148] [Embodiment 3] In embodiments 1 and 2, EML14 1 The example given was the case in which O2 scavenger 31 is included. However, as mentioned above, aprotic 1 The O2 scavenger may be included in at least one of the EML14 and the first functional layer, which are included in the at least one functional layer.

[0149] Hereinafter, a light-emitting element according to one aspect of the present disclosure includes, as at least one functional layer, an EML14 and a first functional layer, wherein the first functional layer is adjacent to the EML14 and 1 We will explain using the case in which O2 scavenging agent 31 is included as an example.

[0150] Furthermore, the following explanation will use the case where the first functional layer is a carrier transport layer as an example, and will also use the case where the light-emitting element has a conventional structure and the carrier transport layer as the first functional layer is ETL15 as an example.

[0151] Figure 5 is a schematic cross-sectional view showing an example of a light-emitting element 51 according to this embodiment.

[0152] The light-emitting element 51 shown in Figure 5, as an example, is equipped with an anode 11, HIL 12, HTL 13, EML 14, ETL 15, and cathode 16 in this order from the bottom layer, similar to the light-emitting elements shown in Embodiments 1 and 2. Also, similar to the light-emitting elements shown in Embodiments 1 and 2, the ETL 15 contains nanoparticles 52 as an ETL material (oxygen-containing compound) containing an oxygen element, such as n-type metal oxides like ZnO and ZnMgO, or organometallic complexes containing an oxygen element such as Alq3.

[0153] However, as shown in Figure 5, the light-emitting element 51 is 1 The O2 scavenging agent 31 is mixed into the ETL 15. The light-emitting element 51 differs in this respect from the light-emitting elements shown in Embodiments 1 and 2.

[0154] In this embodiment, the ratio of 1 part by weight of nanoparticles 52 in ETL15 1 The content ratio of the O2 scavenger 31 is preferably within the range of 0.001 parts by weight or more and 1 part by weight or less. In ETL15, per 1 part by weight of nanoparticles 52 1 If the content ratio of O2 scavenging agent 31 exceeds 1 part by weight, the film quality of ETL15 may deteriorate. On the other hand, in ETL15, the ratio of 1 part by weight of nanoparticles 52 1 If the content ratio of the O2 scavenging agent 31 is less than 0.001 parts by weight, 1 O2 could not be captured sufficiently. 1 There is a risk that O2 may enter EML14 and degrade QD21. Therefore, 1 There is a risk that the degradation of QD21 due to O2 may not be sufficiently suppressed.

[0155] (Method for manufacturing the light-emitting element 51) Figure 6 is a flowchart showing the manufacturing method of the light-emitting element 51 shown in Figure 5.

[0156] In the manufacturing method of the light-emitting element 41 shown in Figure 3, steps S1 (anodic formation step) to S4 (EML formation step) are performed in the same manner as the manufacturing method of the light-emitting element 1 described above, as shown in Figure 4. The method up to this point is the same as that of a general QLED manufacturing method.

[0157] On the other hand, EML material containing nanoparticle 52 as an oxygen element-containing compound and 1 An EML material dispersion containing an O2 scavenger 31 and a solvent is prepared (manufactured) (Step S41, EML material dispersion preparation step). As shown in Figure 6, the nanoparticles 52 (EML material) can be, for example, ZnMgO nanoparticles (hereinafter referred to as "ZnMgO-NP"). In this embodiment, as an example, the EML material dispersion is made of ZnMgO-NP and as shown in Figure 6. 1 Prepare a ZnMgO-NP dispersion containing O2 scavenger 31 and a solvent.

[0158] For example, amphoteric solvents such as IPA and ethanol can be used as the solvent. The concentration of the ETL material in the EML material dispersion can be set appropriately according to the design value of the ETL 15 layer thickness, etc., and is not particularly limited.

[0159] In the above ETL material dispersion, per 1 part by weight of nanoparticles 52 1 The content ratio of the O2 scavenger 31 is as follows: 1 part by weight of nanoparticles 52 in ETL15 1 The content ratio of the O2 scavenger 31 is set to be within the range of 0.001 parts by weight or more and 1 part by weight or less. For this reason, in the above ETL material dispersion, the ratio of 1 part by weight of nanoparticles 52 1 The content ratio of the O2 scavenger 31 is set, for example, within the range of 0.001 parts by weight or more and 1 part by weight or less. In the above ETL material dispersion, per 1 part by weight of nanoparticles 52 1 If the content ratio of the O2 scavenger 31 exceeds 1 part by weight, the film quality of the formed ETL 15 may decrease. On the other hand, in the above ETL material dispersion, per 1 part by weight of nanoparticles 52 1 If the content ratio of the O2 scavenging agent 31 is less than 0.001 parts by weight, 1O2 could not be captured sufficiently. 1 There is a risk that O2 may enter EML14 and degrade QD21. Therefore, 1 There is a risk that the degradation of QD21 due to O2 may not be sufficiently suppressed.

[0160] Next, ETL 15 is formed using the ETL material dispersion (for example, the ZnMgO-NP dispersion) (Step S5, ETL formation step). Note that Step S41 may be performed before Step S5.

[0161] In step S41, the ETL material dispersion (for example, the ZnMgO-NP dispersion) is first applied to the EML 14, which will serve as the base layer for the ETL 15 (step S5a, ETL material dispersion application step). This forms a coating film of the ETL material dispersion. For example, spin coating can be used to apply the ETL material dispersion.

[0162] Next, the coating film is dried by removing the solvent contained in the coating film (i.e., the applied ETL material dispersion) by heating or other means (step S5b, solvent removal step). This removes the nanoparticles 52 and 1 ETL15 is formed, which includes the O2 scavenging agent 31.

[0163] Furthermore, the nanoparticles 52 may have ligands coordinated to them, and the ETL material dispersion and ETL 15 may contain known ligands.

[0164] Subsequently, the cathode 16 is formed (step S6, cathode formation step). This forms the light-emitting element 51 shown in Figure 5.

[0165] Furthermore, the manufacturing method of the light-emitting element 51 is as follows: 1 Except for the addition of the O2 scavenging agent 31, the manufacturing method is the same as that of a typical QLED.

[0166] (Specific example of a method for manufacturing the light-emitting element 51) Next, an example of a manufacturing method for the light-emitting element 51 shown in Figure 5 is presented.

[0167] In this embodiment, as an example, an ITO layer was formed on a substrate 10 as the anode 11. Next, a PEDOT:PSS layer was formed as HIL12 by spin-coating a solution containing PEDOT:PSS onto the ITO layer and then evaporating the solvent by baking. Next, a TFB layer was formed as HTL13 by spin-coating a solution containing TFB onto the PEDOT:PSS layer and then evaporating the solvent by baking.

[0168] On the other hand, QD21, which has an InP / ZnS core / shell structure and a number-average particle size (diameter) of 10 nm, was dispersed in hexane as a solvent at a concentration of 13 mg / mL. This prepared a QD dispersion containing the above QD and solvent.

[0169] Next, the QD dispersion was spin-coated onto the TFB layer at a spin speed of 200 rpm for 30 seconds. Then, by baking at 80°C for 10 minutes to evaporate the hexane, a QD layer containing the QDs, for example with a thickness of 20 nm, was formed on the TFB layer as EML14.

[0170] On the other hand, ZnMgO-NP with a number-average particle size (diameter) of 10 nm was dispersed in ethanol as a solvent to a concentration of 25 mg / mL as nanoparticle 52. Then, the resulting dispersion was used. 1 As the O2 scavenging agent 31, DABCO was added to the ethanol at a ratio of 10 mg / mL. This prepared a ZnMgO-NP dispersion containing 25 mg of ZnMgO-NP and 10 mg of DABCO per 1 mL of ethanol.

[0171] Next, the ZnMgO-NP dispersion was spin-coated onto the QD layer at a spin speed of 200 rpm for 30 seconds. Then, by baking at 80°C for 10 minutes to evaporate the ethanol, an ETL15, for example with a thickness of 50 nm, containing the ZnMgO-NP and DABCO was formed on the QD layer. Next, an Al layer was formed on the ETL15 as the cathode 16.

[0172] (effect) According to this embodiment, as described above, the at least one functional layer includes, for example, EML14 and a first functional layer, wherein the first functional layer is adjacent to EML14 and 1 By including the O2 scavenger 31, 1 This can reduce the risk of O2 entering EML14.

[0173] In particular, carrier transport materials containing oxygen elements (oxygen-containing compounds), such as nanoparticles of metal oxides and nanoparticles of organometallic complexes containing oxygen elements, 1 It can serve as an O2 light source. Since nanoparticles such as ZnMgO also function as photosensitizers, 1 O2 is generated. QD21 and nanoparticles such as ZnMgO 52 are in contact at the stacking interface. Therefore, from ETL15 to EML14 1 The movement of O2 oxidizes QD21.

[0174] However, as mentioned above, for example, ETL15, 1 As O2 scavenger 31, aprotic 1 By including an O2 scavenger, the ETL15 is improved to EML14. 1 This can reduce the risk of O2 intrusion. Also, ETL15, 1 As O2 scavenger 31, aprotic 1 By containing an O2 scavenger, EML14 becomes aprotic 1 Compared to the case containing an O2 scavenger, the above aprotic 1 This can reduce the risk of O2 scavenging agents adversely affecting EML14.

[0175] In addition, in Embodiment 2, 1 a time is provided for the O2 scavenger solution to penetrate into the EML14 so that 1 the O2 scavenger solution and the EML14 come into contact with each other. However, in the step S5a (ETL material dispersion coating step), the time for the ETL material dispersion and the EML14 to come into contact with each other by applying the ETL material dispersion on the EML14 is extremely short whether spin coating is used for the coating or inkjet coating is used. Therefore, in FIG. 5, although the case where the O2 scavenger 31 is slightly included in the EML14 is illustrated as an example, 1 it can be said that the O2 scavenger 31 hardly penetrates into the EML14. 1

[0176] (Modification 1) As described above, in this embodiment as well, the case where the light-emitting element 51 has a conventional structure and the first functional layer is the ETL15 has been described as an example. However, this embodiment is not limited thereto.

[0177] FIG. 7 is a cross-sectional view schematically showing an example of a light-emitting element 61 according to this Modification 1.

[0178] The light-emitting element 61 shown in FIG. 7 includes an anode 11, a HIL 12, a HTL 13, an EML 14, an ETL 15, and a cathode 16 in this order from the lower layer side, similar to the light-emitting element 51 shown in FIG. 5. In this modification, the HTL 13 contains nanoparticles 62 such as a p-type metal oxide such as NiO as a HTL material containing an oxygen element (oxygen element-containing compound). As shown in FIG. 7, the light-emitting element 61 1 has the O2 scavenger 31 mixed in the HTL 13.

[0179] As described above, a carrier transport material containing an oxygen element (oxygen element-containing compound) such as nanoparticles of a metal oxide or nanoparticles of an organometallic complex containing an oxygen element 1 can be a light source of O2. Since nanoparticles such as NiO also function as a photosensitizer, 1 ​It generates O2. Therefore, when HTL13 adjacent to QD21 contains nanoparticles 62 such as NiO as an HTL material (oxygen element-containing compound) containing an oxygen element, O2 moves from HTL13 to EML14, 1 oxidizing QD21. Therefore, the first functional layer may be HTL13.

[0180] Anyway, when the first functional layer 1 contains an aprotic 1 O2 scavenger as the O2 scavenger 31, the possibility of O2 invading from the first functional layer to EML14 can be reduced. Also, when the first functional layer 1 contains an aprotic 1 O2 scavenger as the O2 scavenger 31, the possibility that the aprotic 1 O2 scavenger has an adverse effect on EML14 can be reduced compared with the case where EML14 contains the above aprotic 1 O2 scavenger. 1

[0181] Note that whether the first functional layer is ETL15 or HTL13 as described above, the content ratio of the O2 scavenger 31 to 1 part by weight of the nanoparticles in the first functional layer is preferably in the range of 0.001 part by weight or more and 1 part by weight or less for the same reason as described above. 1

[0182] Also, whether the first functional layer is ETL15 or HTL13 as described above, by including a step of forming EML14 containing QD21 and a step of forming the first functional layer containing the O2 scavenger 31 in the functional layer forming step, 1 [[ID=​​​​​​​​​In Figures 5 and 7, the first functional layer adjacent to EML14 is a carrier transport layer, and this carrier transport layer contains a carrier transport material (oxygen-containing compound) that contains oxygen element, and 1 The example described was that which includes the O2 scavenging agent 31. However, the light-emitting element according to this embodiment is not limited thereto.

[0184] The light-emitting element according to this embodiment includes, for example, an EML14 as the at least one functional layer, a first functional layer, and a second functional layer provided between the first electrode and the first functional layer, wherein the second functional layer contains an oxygen element-containing compound, and the first functional layer is 1 It may also contain an O2 scavenging agent 31.

[0185] The following explanation will use the example where the first functional layer is HTL13 and the second functional layer is HIL12.

[0186] Figure 8 is a schematic cross-sectional view showing an example of a light-emitting element 63 according to this modified example.

[0187] The light-emitting element 63 shown in Figure 8, as an example, is equipped with an anode 11, HIL 12, HTL 13, EML 14, ETL 15, and cathode 16 in this order from the bottom layer, similar to the light-emitting elements shown in Embodiments 1 and 2. As mentioned above, for HIL 12, for example, PEDOT:PSS is used as the HIL material. PEDOT:PSS is an HIL material (oxygen-containing compound) that contains the element oxygen. In this case, where the second functional layer is, for example, HIL 12 and HIL 12 contains an oxygen-containing compound, as shown in Figure 8, the HTL 13 as the first functional layer is 1 It may also contain an O2 scavenging agent 31. In this case, the HTL 13 may be an HTL material that does not contain oxygen, such as the TFB mentioned above.

[0188] Thus, the second functional layer contains an oxygen-containing compound, and the first functional layer is 1 By including the O2 scavenger 31, the second functional layer is transferred to EML14. 1 Before O2 moves, in the first functional layer, 1It can capture O2. Also, in this case, the first functional layer is used instead of EML14. 1 By including the O2 scavenger 31, 1 The risk of the O2 scavenging agent 31 adversely affecting EML14 can be reduced.

[0189] Furthermore, in this case, the portion of the first functional layer (HTL13 in the example shown in Figure 8) that is closer to the second functional layer (HIL12 in the example shown in Figure 8) than the center of the first functional layer in the thickness direction. 1 The density of the O2 scavenger 31 is greater in the portion further from the second functional layer than in the center of the thickness direction of the first functional layer. 1 It is desirable that the density is higher than that of the O2 scavenger 31. In this case, for example, in the first functional layer described above 1 It is more desirable that the density of the O2 scavenger 31 is higher in the thickness direction of the first functional layer, closer to the second functional layer (HIL12 in the example shown in Figure 8). However, in this case, the density of the first functional layer 1 The density distribution of the O2 scavenger 31 does not need to increase linearly the closer it is to the second functional layer; it may increase in steps. In this disclosure, in the first functional layer 1 The density of the O2 scavenger 31 is higher in the part closer to the second functional layer, which means that in the first functional layer... 1 This indicates that the density of the O2 scavenger 31 may increase linearly in the thickness direction of the first functional layer as it approaches the second functional layer, or it may increase gradually as it approaches the second functional layer.

[0190] In this case, efficiently in the portion of the first functional layer that is close to the second functional layer containing the oxygen element compound, 1 It can capture O2. Also, 1 Compared to the case where the O2 scavenging agent 31 is uniformly mixed throughout the first functional layer under the same conditions, 1 The amount of O2 scavenging agent 31 used can be reduced. 1 This reduces the risk of adverse effects from the O2 scavenging agent 31, and also reduces material costs, thereby lowering manufacturing costs.

[0191] (Variation 3) Figures 5, 7, and 8 illustrate the case where the light-emitting element according to this embodiment has a conventional structure. However, the light-emitting element according to this embodiment may also have an inverted structure. Even when the light-emitting element has an inverted structure, the first functional layer may be HTL13 or ETL15.

[0192] [Embodiment 4] As described above, the light-emitting element includes EML14 and a first functional layer as at least one functional layer, and the first functional layer is 1 When the O2 scavenger 31 and an oxygen element-containing compound are included, the first functional layer is not limited to a layer having a carrier transport function as in Embodiment 3. The first functional layer may be any of ETL15, electron injection layer (hereinafter referred to as "EIL"), HTL13, HIL, and intermediate layer.

[0193] Here, "intermediate layer" refers to functional layers other than ETL15, EIL, HTL13, and HIL that are added for various purposes. Note that ETL15 may also be an electron transport layer and electron injection layer. Also, HTL13 or HIL may be a hole transport layer and hole injection layer.

[0194] The objectives mentioned above include, for example, passivation, adjustment of carrier balance (e.g., preventing excessive carrier injection into EML14 by inserting insulating materials), improvement of wettability, and suppression of interlayer material reactions (e.g., interactions such as quenching or alteration due to chemical reactions).

[0195] Examples of materials for the above-mentioned intermediate layer include metal oxides and self-assembled films (self-assembled monolayers, hereinafter referred to as "SAMs").

[0196] As mentioned above, ETL15 uses nanoparticles 52 such as n-type metal oxides like ZnO and ZnMgO, or organometallic complexes containing oxygen, such as Alq3, as the ETL material (oxygen-containing compound) containing oxygen. HTL13 uses nanoparticles 62 such as p-type metal oxides like NiO as the HTL material (oxygen-containing compound) containing oxygen. In Embodiment 3, as a modification, the case in which the HTL material (oxygen-containing compound) containing oxygen is nanoparticles 62 such as p-type metal oxides like NiO, as described above, was explained as an example. However, the organic hole transport materials such as V886 or HN-D1 are also HTL materials (oxygen-containing compounds) containing oxygen. HIL12 uses PEDOT:PSS as the HIL material (oxygen-containing compound) containing oxygen. The intermediate layer may be a passivation layer containing oxygen, such as Al2O3. Examples of SAMs used in the intermediate layer include films composed of 2-(3,6-dimethoxy)-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACz), [2-(9H-carbazole-9-yl)ethyl]phosphonic acid (2PACz), silane coupling agents, etc.

[0197] Furthermore, as described above, if any of the functional layers surrounding EML14, such as ETL15, EIL, HTL13, HIL, and the intermediate layer, contains an oxygen-containing compound, the functional layer containing the oxygen-containing compound may further contain a crosslinking agent.

[0198] The above crosslinking agent may be a photocrosslinking agent or a thermal crosslinking agent. Examples of the above crosslinking agent include a crosslinking agent containing at least one epoxy group. Examples of the above crosslinking agent include 1,2-epoxyoctane and diglycidyl-1,2-cyclohexanedicarboxylate.

[0199] These crosslinking agents contain, for example, an epoxy group as a functional group that easily undergoes a chemical reaction by light, heat, or the like, and may be incorporated into any layer. These crosslinking agents may be used, for example, to crosslink and chemically stabilize EML14, HTL13, or the like.

[0200] Hereinafter, specific examples of the light-emitting device according to the present embodiment will be described.

[0201] FIG. 9 is a cross-sectional view schematically showing an example of the light-emitting device 71 according to the present embodiment.

[0202] The light-emitting device 1 shown in FIG. 9 includes an anode 11, a HIL 12, a HTL 13, a SAM 81, an EML 14, an ETL 15, an EIL 82, and a cathode 16 in this order from the lower layer side.

[0203] In FIG. 9, as an example, a case where the light-emitting device 1 has a conventional structure is illustrated. However, the present embodiment is not limited thereto, and the light-emitting device 71 may have an inverted structure.

[0204] Also, in FIG. 9, as an example, a case where all the functional layers between the anode 11 and the cathode 16 1 include an O2 scavenger 31 is illustrated.

[0205] The light-emitting device 71 shown in FIG. 9 includes a SAM 81 as an intermediate layer between the anode 11 and the cathode 16, includes an EIL 82, and all the functional layers between the anode 11 and the cathode 16 1 include an O2 scavenger 31. Except for this point, the light-emitting device 71 shown in FIG. 9 has the same configuration as the light-emitting devices according to Embodiments 1 to 3.

[0206] EIL82 is a charge injection layer that contains an EIL material (electron transport material) having electron transport properties as a functional material, and has an electron injection function that enhances the electron injection efficiency from cathode 16 to ETL15. Conventional known electron transport materials can be used as the EIL material for EIL82. EIL82 may also contain, for example, Alq3 as an oxygen-containing compound. Furthermore, as described above, EIL82 may contain a crosslinking agent, for example, an epoxy group. EIL82 can be formed by the same method as ETL15.

[0207] The SAM81 shown in Figure 9 is a hole-transporting buffer layer used to improve hole transport and wettability of the QD dispersion applied on the SAM81. It also functions as a buffer layer to prevent the QD21 from chemically degrading due to direct contact between the QD21 and an HTL material such as NiO. The SAM81 is provided between the anode 11 and the EML14 (for example, between the HTL13 and the EML14 as shown in Figure 9). For example, an organic insulating material can be used as the material for the SAM81. Alternatively, the material for the SAM81 may be a hole-transporting material.

[0208] In the following, we will explain the method for forming SAM81, using the example where SAM81 is a self-assembled membrane made of MeO-2PACz, and the underlying layer HTL13 of SAM81 contains NiO nanoparticles as nanoparticles 62.

[0209] SAM81 can be formed on HTL13 by, for example, spin-coating an EBL material solution containing EBL material, and then volatilizing the solvent by baking.

[0210] In this embodiment, MeO-2PACz was dispersed in ethanol as a solvent to a concentration of 0.01 mol / L as the EBL material solution. This prepared a MeO-2PACz-ethanol solution as the EBL material solution. Next, for example, the MeO-2PACz-ethanol solution was spin-coated onto a NiO-NP layer formed as HTL13 on a 25 mm square substrate 10 at a spin speed of 300 rpm for 30 seconds. Subsequently, the ethanol was evaporated by baking at 100°C for 10 minutes, thereby forming a MeO-2PACz layer as SAM81 on the NiO-NP layer.

[0211] The above MeO-2PACz layer 1 To incorporate the O2 scavenger 31, for example, after the formation of the MeO-2PACz layer, the PACz layer is mixed as shown in Embodiment 2. 1 After supplying the O2 scavenging agent solution, 1 The solvent contained in the O2 scavenging agent solution may be removed. Alternatively, the above MeO-2PACz-ethanol solution may be used. 1 By adding O2 scavenger 31, MeO-2PACz and 1 A SAM81 containing an O2 scavenging agent 31 may be formed.

[0212] In any case, the amount of the oxygen-containing compound in each of the above functional layers is 1 part by weight 1 The content ratio of the O2 scavenger 31 is preferably in the range of 0.001 parts by weight or more and 1 part by weight or less, for the same reasons as described in Embodiments 1 to 3.

[0213] Furthermore, as mentioned above, in Figure 9, as an example, all functional layers between the anode 11 and cathode 16 are 1 An example is shown in which the O2 scavenging agent 31 is included. However, in one aspect of the present disclosure, between the anode 11 and the cathode 16, 1 It is sufficient to have at least one layer containing the O2 scavenging agent 31. Therefore, in the functional layer formation process, 1 It is sufficient to form at least one layer containing the O2 scavenging agent 31.

[0214] Furthermore, although Figure 9 uses the case where the intermediate layer is SAM81 as an example, as mentioned above, the intermediate layer is a functional layer other than ETL15, EIL, HTL13, and HIL that is added for various purposes. The intermediate layer may be, for example, a hole blocking layer or an electron blocking layer, or it may be a passivation layer.

[0215] This disclosure is not limited to the embodiments described above, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of this disclosure. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment. [Explanation of Symbols]

[0216] 1, 41, 51, 61, 63, 71 Light-emitting elements 11. Anode (first electrode or second electrode) 12. HIL (Functional Layer, First Functional Layer, Second Functional Layer) 13. HTL (Functional Layer, First Functional Layer) 14 EML (Emitting Layer) 15 ETL (Functional Layer, First Functional Layer) 16. Cathode (first electrode or second electrode) 21 QD (Quantum Dots) 31 1 O2 scavenger 52, 62 nanoparticles 81 SAM (Intermediate Layer, Functional Layer, First Functional Layer) 82 EIL (Functional Layer, First Functional Layer, Second Functional Layer)

Claims

1. It comprises a first electrode and a second electrode, Between the first electrode and the second electrode, there is at least one functional layer containing a non-protic singlet oxygen scavenger. Between the first electrode and the second electrode, a functional layer comprising a light-emitting layer containing quantum dots and a first functional layer other than the light-emitting layer is provided. The above-mentioned first functional layer is adjacent to the above-mentioned light-emitting layer and contains an oxygen element-containing compound, The above-mentioned light-emitting layer contains the above-mentioned aprotic singlet oxygen scavenger, A light-emitting element characterized in that the density of the aprotic singlet oxygen scavenger in the portion of the light-emitting layer closer to the first functional layer than to the center of the light-emitting layer in the thickness direction is higher than the density of the aprotic singlet oxygen scavenger in the portion of the light-emitting layer further from the first functional layer than to the center of the light-emitting layer in the thickness direction.

2. The light-emitting element according to claim 1, characterized in that the above-mentioned aprotic singlet oxygen scavenger includes at least one compound selected from the group consisting of tertiary amines, carotenoids, ethylenic compounds, naphthalenes and their derivatives, and anthracenes and their derivatives.

3. The light-emitting element according to claim 1 or 2, characterized in that it comprises a tertiary amine as the above-mentioned aprotic singlet oxygen scavenger.

4. The light-emitting element according to claim 3, characterized in that the above tertiary amine includes at least one selected from the group consisting of 1,4-diazabicyclo[2.2.2]octane, triethylamine, and N,N-dimethylaniline.

5. The light-emitting element according to claim 1 or 2, characterized in that the above-mentioned aprotic singlet oxygen scavenger is a monomer.

6. The light-emitting element according to claim 1, characterized in that the density of the aprotic singlet oxygen scavenger in the light-emitting layer is higher in the portion of the light-emitting layer that is closer to the first functional layer in the thickness direction of the light-emitting layer.

7. It comprises a first electrode and a second electrode, Between the first electrode and the second electrode, there is at least one functional layer containing a non-protic singlet oxygen scavenger. Between the first electrode and the second electrode, the device comprises a functional layer comprising a light-emitting layer containing quantum dots, a first functional layer other than the light-emitting layer, and a second functional layer provided between the first electrode and the first functional layer. The above-mentioned second functional layer contains an oxygen-containing compound, The above-mentioned first functional layer includes the above-mentioned aprotic singlet oxygen scavenger, A light-emitting element characterized in that, in the first functional layer, the density of the aprotic singlet oxygen scavenger in the portion closer to the second functional layer than to the center of the first functional layer in the thickness direction is higher than the density of the aprotic singlet oxygen scavenger in the portion further from the second functional layer than to the center of the first functional layer in the thickness direction.

8. The light-emitting element according to claim 7, characterized in that the density of the aprotic singlet oxygen scavenger in the first functional layer is higher in the portion of the first functional layer that is closer to the second functional layer in the thickness direction of the first functional layer.

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