Organic light-emitting element

Abstract

The present disclosure provides an organic light-emitting element comprising a first electrode 200, a first light-emitting unit 300, a charge-generating layer 400, a second light-emitting unit 500, and a second electrode 600 in this order. The first light-emitting unit 300 has a first organic layer 303, a first light-emitting layer 304, and a second organic layer 305 which are adjacent to one another in this order, and exhibits hole injection properties.

Description

Organic light-emitting devices

[0001] The present invention relates to an organic light-emitting element and various devices and apparatuses having the organic light-emitting element.

[0002] An organic electroluminescence element (hereinafter also referred to as an "organic EL element" or an "organic light-emitting element") is an element that emits light when a current is passed through an organic compound layer that includes an anode, a cathode, and a light-emitting layer disposed between these electrodes.

[0003] In recent years, in addition to monochrome organic light-emitting elements that emit white light by having light-emitting materials that emit red, green, and blue light in one light-emitting layer, stacked organic light-emitting elements have been developed in which light-emitting layers that emit red, green, and blue light are stacked. Stacked organic light-emitting elements tend to have a higher driving voltage than single-layer organic light-emitting elements that have only one light-emitting layer, so a structure in which an intermediate layer called a charge generation layer or intermediate electrode is provided is known. However, such intermediate layers may be more susceptible to deterioration than other organic layers, and deterioration of such intermediate layers leads to higher voltages, lower efficiency, and reduced durability, so there is a demand for the development of stable charge generation layers.

[0004] Patent Document 1 describes a configuration having a charge generation layer, in which the LUMO of the lower layer and the HOMO and LUMO of the charge generation layer are specified, and the energy level between the charge generation layer and its adjacent layer is specified. Patent Document 2 describes a configuration having a charge generation layer, in which the LUMO level difference between the light-emitting layer and the electron blocking layer is specified.

[0005] JP 2022-117963 A JP 2023-029747 A

[0006] However, the stacked organic light-emitting device described in Patent Document 1 has a charge generation layer, and while the lower layer (layer between the anode and the charge generation layer) has energy specifications for the charge generation layer and its adjacent layers, such as LUMOs of the first material and the second material, specifications for the light-emitting layer and its adjacent layers are not made, and the viewpoint of injection properties is not taken into account. In other words, while electron injection properties are important in charge injection from the charge generation layer to the light-emitting layer, Patent Document 1 does not take this point into consideration, which is thought to deteriorate the carrier balance originating from the charge generation layer, and as a result, there is a concern that the durability of the organic light-emitting device will deteriorate.

[0007] Furthermore, in the stacked organic light-emitting device described in Patent Document 2, there is a concern that the carrier balance may be deteriorated due to the charge generation layer for the same reason as above.

[0008] The present invention has been made in view of the above problems, and an object of the present invention is to provide an organic light-emitting device that is highly efficient and has excellent durability.

[0009] The organic light-emitting element of the present invention has a first electrode, a first light-emitting unit, a charge generating layer, a second light-emitting unit, and a second electrode in this order, and the first light-emitting unit has a first organic layer, a first light-emitting layer, and a second organic layer adjacent to each other in this order, and the first organic layer contains organic compound A, the first light-emitting layer contains organic compound B, and the second organic layer contains organic compound C, and is characterized in that the relationship represented by the following formula [1] is satisfied: ΔLUMO1≧0 [1] ΔLUMO1=LUMO(C)−LUMO(B), LUMO(B): LUMO level of organic compound B, LUMO(C): LUMO level of organic compound C.

[0010] According to the present invention, it is possible to provide an organic light-emitting device that is highly efficient and has excellent durability.

[0011] FIG. 1 is a cross-sectional view of an organic light-emitting element according to one embodiment of the present invention. FIG. 2 is a cross-sectional view of an example of a pixel of a display device according to one embodiment of the present invention. FIG. 3 is a cross-sectional view of an example of a display device using an organic light-emitting element according to one embodiment of the present invention. FIG. 4 is a cross-sectional view of an example of a display device according to one embodiment of the present invention. FIG. 5 is a cross-sectional view of an example of an imaging device according to one embodiment of the present invention. FIG. 6 is a cross-sectional view of an example of an electronic device according to one embodiment of the present invention. FIG. 7 is a cross-sectional view of an example of a display device using an organic light-emitting element according to one embodiment of the present invention. FIG. 8 is a cross-sectional view of an example of a display device according to one embodiment of the present invention. FIG. 9 is a cross-sectional view of an example of an imaging device according to one embodiment of the present invention. FIG. 10 is a cross-sectional view of an example of an electronic device using an organic light-emitting element according to one embodiment of the present invention. FIG. 11 is a cross-sectional view of an example of a display device using an organic light-emitting element according to one embodiment of the present invention. FIG. 12 is a cross-sectional view of an example of an imaging device according to one embodiment of the present invention.

[0012] <Organic Light-Emitting Element> The organic light-emitting element of the present invention is a stacked organic light-emitting element having a first light-emitting unit on the first electrode side and a second light-emitting unit on the second electrode side, with a charge-generating layer interposed between a first electrode and a second electrode. The first light-emitting unit has a first organic layer, a first light-emitting layer, and a second organic layer, in this order, which are adjacent to each other. The first organic layer contains organic compound A, the first light-emitting layer, and organic compound B, and the second organic layer contains organic compound C, respectively, and satisfies the following formula [1]: ΔLUMO1≧0 [1] ΔLUMO1=LUMO(C)−LUMO(B) LUMO(B): LUMO level of organic compound B LUMO(C): LUMO level of organic compound C

[0013] In the present invention, HOMO stands for highest occupied molecular orbital, and its energy level is referred to as HOMO level or HOMO. LUMO stands for lowest unoccupied molecular orbital, and its energy level is referred to as LUMO level or LUMO. Both are expressed in units of eV.

[0014] In the organic light-emitting device according to this embodiment, the first electrode may be an anode, and the second electrode may be a cathode.

[0015] The present invention will be described in more detail below with reference to FIG.

[0016] FIG. 1 is a cross-sectional schematic diagram of one embodiment of the organic light-emitting element according to the present embodiment, in which a first electrode 200, a first light-emitting unit 300, a charge generation layer 400, a second light-emitting unit 500, and a second electrode 600 are laminated in this order on a substrate 1.

[0017] In the organic light-emitting device according to this embodiment, the first light-emitting unit 300 includes at least a first organic layer 303, a first light-emitting layer 304, and a second organic layer 305, which are arranged in this order and adjacent to one another. The first organic layer 303 includes an organic compound A, the first light-emitting layer 304 includes an organic compound B, and the second organic layer 305 includes an organic compound C. In the organic light-emitting device according to this embodiment, the first light-emitting unit 300 may include a first hole-injection layer 301, a first hole-transport layer 302, a first electron-transport layer 306, and a first electron-injection layer 307, as shown in FIG.

[0018] In this embodiment, the first organic layer 303 functions as an electron blocking layer, and the second organic layer 305 functions as a hole blocking layer.

[0019] In the organic light-emitting device according to this embodiment, the second light-emitting unit 500 includes a third organic layer 502, a second light-emitting layer 503, and a fourth organic layer 504, in this order. Preferably, a third light-emitting layer (not shown) is included between the second light-emitting layer 503 and the fourth organic layer 504. The third organic layer 502 and the second light-emitting layer 503, and the third light-emitting layer and the fourth organic layer 504 are adjacent to each other. When the third light-emitting layer is not included, the second light-emitting layer 503 and the fourth organic layer 504 are adjacent to each other. Furthermore, the third organic layer 502 includes organic compound D, the second light-emitting layer 503 includes organic compound E, the third light-emitting layer includes organic compound F, and the fourth organic layer 504 includes organic compound G. The second light-emitting unit 500 may include other layers as necessary. Specifically, as shown in FIG. 1 , the second light-emitting unit 500 may include a second hole-transporting layer 501, a second electron-transporting layer 505, and a second electron-injecting layer 506.

[0020] In this embodiment, the third organic layer 502 functions as an electron blocking layer, and the fourth organic layer 504 functions as a hole blocking layer.

[0021] Furthermore, in the organic light-emitting device according to this embodiment, the charge generation layer 400 has at least one n-type charge generation layer. The charge generation layer 400 serves to inject electrons into the first light-emitting unit 300. Therefore, the organic light-emitting device according to this embodiment does not need to have the first electron injection layer 307. By not providing the first electron injection layer 307, it is expected that the driving voltage of the organic light-emitting device according to this embodiment can be reduced.

[0022] Furthermore, when the organic light-emitting element according to this embodiment has the first electron injection layer 307, it is preferable that the first electron injection layer 307 is provided adjacent to the n-type charge generation layer, and that the n-type charge generation layer and the first electron injection layer 307 contain a common material. In this case, the adhesion between the n-type charge generation layer and the first electron injection layer 307 is increased, thereby further improving the function as an electron injection layer.

[0023] Specific configurations of the charge generation layer 400 according to this embodiment are shown below, but are not limited to these. In the following configurations, the n-type charge generation layer is located on the anode side. (i) n-type charge generation layer / hole injection layer (ii) n-type charge generation layer / p-type charge generation layer (iii) n-type charge generation layer / connection layer / hole injection layer (iv) n-type charge generation layer / connection layer / p-type charge generation layer

[0024] In the organic light-emitting device according to this embodiment, the n-type charge generation layer may contain an organic compound having high electron donating properties, such as an alkali metal atom, an alkaline earth metal atom, or a compound having an imidazolidine skeleton, and preferably contains an alkali metal atom or an alkaline earth metal atom, and more preferably contains a lithium atom or a cesium atom. The n-type charge generation layer may also be a mixed layer containing a first organic compound and a second organic compound.

[0025] The first organic compound is, for example, a nitrogen-containing aromatic compound. Specific examples include phenanthrolinyl, oxazolyl, oxadiazolyl, diazolyl, thiadiazolyl, triazolyl, naphthyridinyl, and derivatives thereof. Among these, the first organic compound is preferably a phenanthroline derivative or a naphthyridine derivative. Phenanthroline derivatives and naphthyridine derivatives have particularly strong interactions with alkali metals, and are therefore particularly preferred as materials for the n-type charge generation layer.

[0026] The second organic compound is a condensed polycyclic hydrocarbon compound or an organic compound represented by any of the general formulae (A-1) to (A-10).

[0027]

[0028] In the above general formulas (A-1) and (A-2), R １ ~R ９０９ are each independently selected from the group consisting of a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted silyl group, and a substituted or unsubstituted amino group.

[0029] The p-type charge generation layer may be a mixed layer containing a hole transporting compound and an electron withdrawing compound. The hole injection layer may be a layer containing an electron withdrawing compound or a metal oxide. The connection layer may be a layer containing an electron transporting compound or a hole transporting compound.

[0030] Examples of alkali metal atoms include, but are not limited to, lithium, sodium, potassium, rubidium, and cesium atoms, with lithium and cesium atoms being preferred.

[0031] Examples of alkaline earth metal atoms include, but are not limited to, beryllium atoms, magnesium atoms, calcium atoms, and strontium atoms.

[0032] The organic compound contained in the charge generating layer is, for example, a nitrogen-containing aromatic compound. Specific examples include phenanthrolinyl, oxazolyl, oxadiazolyl, diazolyl, thiadiazolyl, triazolyl, naphthyridinyl, and derivatives thereof. Among these, phenanthroline derivatives and naphthyridine derivatives are preferred. Phenanthroline derivatives and naphthyridine derivatives have particularly strong interactions with alkali metals, making them particularly preferred materials for the n-type charge generating layer.

[0033] The connection layer may be a layer containing an electron transport compound or a hole transport compound. An n-type organic semiconductor layer containing a compound with a LUMO of -5.0 eV or less may be provided between the n-type charge generation layer and the p-type charge generation layer. The connection layer may also be a layer made of a condensed polycyclic hydrocarbon compound, and more preferably a layer made only of a condensed polycyclic hydrocarbon compound. The connection layer may have both a layer containing an electron transport compound or a hole transport compound and a layer made of a condensed polycyclic hydrocarbon compound.

[0034] The charge generation layer 400 serves to inject electrons into the first light-emitting unit 300. Therefore, in the organic light-emitting device according to this embodiment, the first light-emitting unit 300 does not need to have the first electron injection layer 307. When the first light-emitting unit 300 does not have the first electron injection layer 307, the driving voltage of the organic light-emitting device can be reduced.

[0035] Furthermore, in the organic light-emitting device according to this embodiment, the first light-emitting unit 300 may include a first electron injection layer 307. In this case, it is preferable that the first electron injection layer 307 and the charge generation layer 400 share a common material, and it is also preferable that the first electron injection layer 307 and the n-type charge generation layer share a common material. When the first electron injection layer 307 and the charge generation layer 400 share a common material, the adhesion between the first electron injection layer 307 and the charge generation layer 400 is increased, thereby further improving the function as an electron injection layer.

[0036] The charge generation layer 400 serves to inject holes into the second light-emitting unit 500. Therefore, in the organic light-emitting device according to this embodiment, the second light-emitting unit 500 may or may not have a second hole injection layer. When the second light-emitting unit 500 does not have a second hole injection layer (not shown), the driving voltage of the organic light-emitting device can be reduced.

[0037] Furthermore, when the second light-emitting unit 500 has a second hole injection layer, it is preferable that the second hole injection layer and the charge generation layer 400 have a common material, and it is also preferable that the second hole injection layer and the p-type charge generation layer or the hole injection layer of the charge generation layer 400 have a common material. When the second hole injection layer and the charge generation layer 400 have a common material, the adhesion between the second hole injection layer and the charge generation layer 400 is increased, and the function as a hole injection layer is further improved.

[0038] The organic light-emitting device according to this embodiment may have a third light-emitting unit in addition to the first light-emitting unit 300 and the second light-emitting unit 500. The third light-emitting unit may be provided between the first electrode 200 and the first light-emitting unit 300, between the first light-emitting unit 300 and the second light-emitting unit 500, or between the second light-emitting unit 500 and the second electrode 600.

[0039] Furthermore, the organic light-emitting device according to this embodiment may have an element configuration capable of emitting white light. Specifically, the first light-emitting unit 300 may emit blue light, and the second light-emitting unit 500 may emit red and green light. Alternatively, the first light-emitting unit 300 may emit red and green light, and the second light-emitting unit 500 may emit blue light. The first light-emitting unit 300, the second light-emitting unit 500, and the third light-emitting unit may emit red, green, and blue light, respectively.

[0040] Furthermore, the organic light-emitting device according to this embodiment may have a device configuration capable of emitting light other than white. Specifically, the first light-emitting unit 300 and the second light-emitting unit 500 may emit light of the same color. By using such a device configuration, an organic light-emitting device with improved brightness can be manufactured.

[0041] The light-emitting material may be either a fluorescent material or a phosphorescent material. Preferred examples of the light-emitting material include a structure in which the first light-emitting layer 304 and the second light-emitting layer 503 all contain fluorescent materials, a structure in which the first light-emitting layer 304, the second light-emitting layer 503, and the third light-emitting layer all contain fluorescent materials, and a structure in which the first light-emitting layer 304 contains a fluorescent material and the second light-emitting layer 503 or the second light-emitting layer 503 and the third light-emitting layer all contain phosphorescent materials.

[0042] In the organic light-emitting device according to this embodiment, the first light-emitting layer 304, the second light-emitting layer 503, and the third light-emitting layer each contain a host compound, an assist compound, and a light-emitting compound.

[0043] Here, the host compound is the compound with the largest mass ratio among the compounds constituting the light-emitting layer. The guest compound is the compound with a mass ratio smaller than that of the host compound among the compounds constituting the light-emitting layer, and is the compound that is primarily responsible for emitting light. The assist compound is the compound with a mass ratio smaller than that of the host compound among the compounds constituting the light-emitting layer, and assists the light emission of the guest compound. The assist compound is also called a second host compound.

[0044] In this embodiment, the organic compound B contained in the first light-emitting layer 304, the organic compound E contained in the second light-emitting layer 503, and the organic compound F contained in the third light-emitting layer are preferably host compounds or assist compounds.

[0045] In the organic light-emitting device according to this embodiment, the effect of satisfying formula [1] will be described below.

[0046] Table 1 below shows the combinations of organic compounds A to C in the first light-emitting units of Example 1 and Comparative Examples 1 and 2 in Table 4 described later.

[0047]

[0048] In Table 1, in both Comparative Examples 1 and 2, ΔLUMO1<0 eV, whereas in Example 1, ΔLUMO1≧0 eV.

[0049] This indicates that the light-emitting layer of Example 1 has good electron injection properties from the charge generation layer. Because of its good electron injection properties, electrons generated from the charge generation layer are smoothly injected into the light-emitting layer in the first light-emitting unit located between the charge generation layer and the anode. On the other hand, if charges from the charge generation layer accumulate, this can easily cause deterioration of the charge generation layer, leading to a decrease in the functionality of the charge generation layer. Charge accumulation also leads to deterioration of surrounding layers, resulting in a decrease in durability and a decrease in the carrier recombination rate within the first light-emitting layer. In other words, improving the electron injection properties of the first light-emitting layer is essential from the standpoints of durability and efficiency.

[0050] Incidentally, the electron injection property of the lower layer is expressed by ΔLUMO1 in formula [1]. Here, when the lower layer exhibits electron injection property (ΔLUMO1≧0), it becomes possible to improve durability and efficiency for the reasons described above.

[0051] In the organic light-emitting device according to this embodiment, the lower layer preferably has a higher electron injection ability than a hole injection ability, as shown in the following formula [1-1]. The hole injection ability of the lower layer is expressed by the following ΔHOMO1: ΔHOMO1<ΔLUMO1 and ΔLUMO≧0 [1-1] ΔHOMO1=HOMO(B)−HOMO(A) HOMO(A): HOMO level of organic compound A HOMO(B): HOMO level of organic compound B

[0052] In particular, it is preferable that ΔLUMO1≧0>ΔHOMO1 or ΔLUMO1>ΔHOMO1>0. By satisfying these relationships, electrons supplied from the charge generation layer 400 are more easily injected into the lower layer. In particular, when ΔLUMO1>ΔHOMO1>0, holes are also more easily injected into the lower layer, making it easier to keep the recombination region of electrons and holes within the lower layer. As a result, the organic light-emitting element according to this embodiment can be expected to have improved luminous efficiency.

[0053] Furthermore, the organic light-emitting device according to this embodiment preferably has the following configurations (1-1) to (1-4).

[0054] (1-1) The second light-emitting unit has a third organic layer, a second light-emitting layer, a third light-emitting layer, and a fourth organic layer in this order, and the third organic layer and the second light-emitting layer are adjacent to each other, and the third light-emitting layer and the fourth organic layer are adjacent to each other. The third organic layer has organic compound D, the second light-emitting layer has organic compound E, the third light-emitting layer has organic compound F, and the fourth organic layer has organic compound G, and satisfies the following formula [1-2]. In particular, it is more preferable that formula [1-3] is satisfied. More specifically, it is preferable that formula [1-4] or [1-5] is satisfied. ΔHOMO2≧0 [1-2] ΔHOMO2>ΔLUMO2 and ΔHOMO2≧0 [1-3] ΔHOMO2≧0>ΔLUMO2 [1-4] ΔHOMO2>ΔLUMO2>0 ​​[1-5] ΔHOMO2=HOMO(E)-HOMO(D) ΔLUMO2=LUMO(G)-LUMO(F) HOMO(E): HOMO level of organic compound E HOMO(D): HOMO level of organic compound D LUMO(G): LUMO level of organic compound G LUMO(F): LUMO level of organic compound F

[0055] (1-2) The third light-emitting layer preferably contains at least an organic compound F and an organic compound H, and satisfies the relationship represented by the following formula [2]. It is preferable that when one of the organic compounds F and H is a host material, the other is an assist material or a guest material, and when one is an assist material, the other is a guest material. HOMO(H)<HOMO(F) [2] HOMO(F): HOMO level of the organic compound F HOMO(H): HOMO level of the organic compound H

[0056] (1-3) The third light-emitting layer preferably contains at least an organic compound F and an organic compound H, and satisfies the relationship represented by the following formula [3]. Preferably, one of the organic compounds F and H is a host material and the other is an assist material. LUMO(F)<LUMO(H) [3] LUMO(F): LUMO level of the organic compound F LUMO(H): LUMO level of the organic compound H

[0057] The above (1-1) indicates that the second light-emitting unit has a hole-injecting property, (1-2) indicates that the third light-emitting layer has a hole-trapping property, and (1-3) indicates that the third light-emitting layer has an electron-trapping property.

[0058] The hole-injecting property of the second light-emitting unit located closer to the cathode than the charge-generating layer allows holes generated from the charge-generating layer to be smoothly injected into the second light-emitting layer, which leads to improved durability and efficiency of the second light-emitting unit for the same reasons as the electron-injecting property of the first light-emitting unit.

[0059] Furthermore, the electron trapping property leads to the recombination of holes generated from the charge generating layer closer to the cathode, enabling the holes to be injected into the second light-emitting layer without stagnation, which in turn leads to the suppression of charge accumulation, which in turn leads to the suppression of deterioration of the layers surrounding the light-emitting layer, thereby improving durability.

[0060] Furthermore, the hole-trapping property can reduce holes leaking from the upper layer, and the recombination region of electrons and holes can be confined within the upper layer. As a result, the organic light-emitting device according to this embodiment exhibits excellent luminous efficiency and durability.

[0061] It is preferable that the third light-emitting layer satisfies the relationship expressed by the following formula [3-1]: LUMO(H)-LUMO(F)≧0.2 eV [3-1]

[0062] As a result of investigation, it was found that by satisfying the above formula [3-1], the difference in LUMO levels between the organic compound F and the organic compound H in the third light-emitting layer is sufficient, and sufficient electron trapping properties are exhibited.

[0063] Furthermore, it is preferable that the third light-emitting layer satisfies the relationship expressed by the following formula [2-1]: HOMO(F)-HOMO(H)>0.2 eV [2-1]

[0064] As a result of investigation, it was found that by satisfying the above formula [2-1], the difference in HOMO levels between the organic compound F and the organic compound H in the third light-emitting layer is sufficient, and sufficient hole-trapping properties are exhibited.

[0065] Furthermore, in the material contained in the first light-emitting layer, it is preferable that all of the freely rotatable bonds are made of carbon, since this provides high bond energy, structural stability, and improved durability.

[0066] The material contained in the first light-emitting layer preferably contains at least one of a pyrene derivative, a perylene derivative, an anthracene derivative, or a fluoranthene derivative. These compounds have high electron mobility and can rapidly transfer electrons from the charge generating layer, thereby suppressing charge accumulation and improving durability.

[0067] In this specification, the closer the HOMO and LUMO are to the vacuum level, the higher they are described as being. The LUMO of the charge generation layer being lower than the HOMO of the hole transport layer means that the LUMO of the charge generation layer is farther from the vacuum level than the HOMO of the hole transport layer.

[0068] The HOMO and LUMO can be calculated using molecular orbital calculations. The molecular orbital calculations may be performed using density functional theory (DFT) or the like, with the functional being B3LYP and the basis function being 6-31G* or the like.Molecular orbital calculations can be performed, for example, using Gaussian 09 (Gaussian 09, Revision C.01, M. J. Frisch, G. W. Trucks, H. B. Schlegel, G. E. Scuseria, M. A. Robb, J. R. Cheeseman, G. Scalmani, V. Barone, B. Mennucci, G. A. Petersson, H. Nakatsuji, M. Caricato, X. Li, H. P. Hratchian, A. F. Izmaylov, J. Bloino, G. Zheng, J. L. Sonnenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasagawa, M. Ishida, T. Nakajima, Y. Honda, O. Kitao, H. Nakai, T. Vreven, J. A. Montgomery, Jr., J. E. Peralta, F. Ogliaro, M. Bearpark, J. J. Heyd, E. Brothers, K. N. Kudin, V. N. Staroverov, T. Keith, R. Kobayashi, J. Normand, K. Raghavachari, A. Rendell, J. C. Burant, S. S. Iyengar, J. Tomasi, M. Cossi, N. Rega, J. M. Millam, M. Klen, J. E. Knox, J. B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gompertz, R. E. Stratmann, O. Yazyev, A. J. Austin, R. Cammi, C. Pomelli, J. W. Ochterski, R. L. Martin, K. Morokuma, V. G. Zakrzewski, G. A. Voth, P. Salvador, J. J. Dannenberg, S. Dapprich, A. D. Daniels, O. Farkas, J. B. Foresman, J. V. Ortiz, J. Cioslowski, and D. J. Fox, Gaussian, Inc., Wallingford CT, 2010.).

[0069] The HOMO and LUMO can be calculated using the ionization potential and band gap. The HOMO can be estimated by measuring the ionization potential. The ionization potential can be measured by depositing the compound to be measured on a substrate such as glass to form a deposited film, and measuring the deposited film with a measuring device such as an AC-3. The ionization potential can be measured by depositing the compound to be measured on a substrate such as glass and irradiating the deposited film with excitation light. The band gap can be measured by measuring the absorption edge of the absorption spectrum where the deposited film absorbs excitation light.

[0070] The LUMO can be calculated using the band gap and ionization potential values. The LUMO can be estimated by adding the band gap value to the ionization potential.

[0071] The LUMO can also be estimated from the reduction potential. For example, the one-electron reduction potential is estimated using CV (cyclic volmetry) measurement. CV measurement is performed, for example, in a 0.1 M tetrabutylammonium perchlorate solution in DMF, and a Ag / Ag reference electrode is used. ＋ Measurements can be performed using a Pt counter electrode and a glassy carbon working electrode. The LUMO can be estimated by subtracting the difference between the reduction potential of the obtained compound and that of ferrocene from the ionization potential of ferrocene, which is −4.8 eV.

[0072] In the present invention, the ionization potential and band gap of the above-described vapor-deposited film are measured, the HOMO is estimated from the obtained ionization potential, and the LUMO is calculated by adding the band gap to the ionization potential.

[0073] The durability of an organic light-emitting element can be evaluated by the time it takes for its luminance to deteriorate. By comparing the time it takes for its luminance to deteriorate from its initial luminance to a certain level, it can be expressed that the longer the time, the better its durability.

[0074] Furthermore, the organic light-emitting device according to this embodiment preferably has the following characteristics.

[0075] (1-3) The freely rotatable bond in the organic compound C is a carbon-carbon bond. In the organic light-emitting device according to this embodiment, the freely rotatable single bond in the organic compound C and the organic compound H is preferably a carbon-carbon bond, and the freely rotatable single bond is preferably an sp ２ Carbon-sp ２ It is more preferable that the freely rotatable single bonds are carbon-carbon bonds, and it is more preferable that all the freely rotatable single bonds are carbon-carbon bonds, and it is more preferable that all the freely rotatable single bonds are sp ２ Carbon-sp ２ The same applies to organic compound F or organic compound H.

[0076] The organic light-emitting element according to this embodiment has a configuration in which holes are injected into the first light-emitting layer via organic compound C. Organic compound C also plays a role in generating excitons in the organic light-emitting element. Therefore, organic compound C preferably has a skeleton that is resistant to decomposition in the presence of holes or in a high-energy excited state. In this specification, a freely rotatable single bond refers to a bond in which unit A and unit B are not fused together, when the single bond between unit A and unit B is represented by "A-B." Units A and B may be atoms such as carbon atoms or nitrogen atoms, or molecules such as benzene or carbazole. Table 2 shows the bond energies of each bond.

[0077]

[0078] The bond energy of F1 and F2, which have carbon-nitrogen bonds, is 3.9 eV. On the other hand, the bond energy of F3, which has a freely rotatable carbon-carbon bond, is 4.5 eV. ２ The bond energy of F4, which has a bond between carbon atoms, is 5.0 eV. Therefore, when the freely rotatable single bond is a carbon-carbon bond, it is preferable because the skeleton is difficult to decompose. Among carbon-carbon bonds, sp ２ The bond between carbon atoms has particularly high bond energy, so the freely rotatable single bond is sp ２ Carbon-sp ２ A carbon-bonded skeleton is more preferred because it is less susceptible to decomposition.

[0079] (1-4) Organic compound H is a compound having a fused polycyclic hydrocarbon skeleton which may have a substituent, or a heterocyclic skeleton which may have a substituent. In the organic light-emitting device according to this embodiment, organic compound H is preferably a compound having a fused polycyclic hydrocarbon skeleton which may have a substituent, or a heterocyclic skeleton which may have a substituent.

[0080] The condensed polycyclic hydrocarbon skeleton may be a skeleton having 10 to 25 carbon atoms, and specific examples thereof include a naphthalene skeleton, a fluorene skeleton, an anthracene skeleton, a phenanthrene skeleton, a pyrene skeleton, a chrysene skeleton, a triphenylene skeleton, a tetracene skeleton, a fluoranthene skeleton, and a perylene skeleton.

[0081] The heterocyclic skeleton may be a skeleton having 3 to 30 carbon atoms, or may be a skeleton having 3 to 18 carbon atoms, and examples thereof include a dibenzofuran skeleton, a dibenzothiophene skeleton, a xanthone skeleton, a thioxanthone skeleton, a carbazole skeleton, an indolocarbazole skeleton, and a triazine skeleton.

[0082] The organic compound H is preferably a compound having a triphenylene skeleton, a xanthone skeleton, or an indolocarbazole skeleton. In other words, the host compound is preferably a triphenylene derivative, a xanthone derivative, or an indolocarbazole derivative. These have highly planar skeletons, which enhance charge mobility. This makes it easier to inject charges into the light-emitting layer, resulting in a lower driving voltage.

[0083] Specific examples of the organic compound H include compounds represented by the following general formulas (B) to (D) and exemplary compounds EM1 to EM40 described later, but are not limited to these.

[0084]

[0085] In general formula (B), Ar １ and Ar ２are each independently selected from a substituted or unsubstituted aryl group consisting of three or more rings, or a substituted or unsubstituted heterocyclic group consisting of three or more rings. The substituent represented by R is selected from a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted silyl group, or a cyano group. When there are multiple R, the multiple R may be the same or different. n is an integer of 2 to 5, and m1 to m3 are each an integer of 0 to 4.

[0086] The compound of general formula (B) may have at least one of the following characteristics: (B-1) In general formula (1), Ar １ and Ar ２ does not have an SP3 carbon. (B-2) In general formula (1), the substituent represented by R is bonded to the m-position of the benzene constituting the phenylene chain. (B-3) In general formula (1), m1 to m3 are 0. (B-4) In general formula (1), n ​​is 3 or 4. (B-5) In general formula (1), Ar １ and Ar ２ (B-6) In the general formula (1), Ar １ and Ar ２ When Ar is a dibenzothiophene skeleton or a dibenzofuran skeleton, the organic compound has at least one substituent. １ and Ar ２ One of the groups is a substituted or unsubstituted aryl group consisting of three or more rings, and the other is a substituted or unsubstituted heterocyclic group consisting of three or more rings.

[0087]

[0088] In general formulas (C) and (D), the cyclic units A to C are each independently selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. １ ~Q ３ is a direct bond, C(R Ａ ) (R Ｂ ), N(RＣ ), an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom. Ａ ~R Ｃ are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group. Ｃ The cyclic units A to C form a ring together with the adjacent cyclic units A to C.

[0089] Specific examples of the skeletons represented by general formulas (C) and (D) are as follows:

[0090]

[0091] Specific examples of general formulas (B) to (D) are shown below, but the invention is not limited to these.

[0092]

[0093]

[0094]

[0095]

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105] (1-5) The upper layer is a phosphorescent-emitting layer and the lower layer is a fluorescent-emitting layer. In the organic light-emitting device according to this embodiment, when the lower layer contains a first light-emitting material and the upper layer contains a second light-emitting material, it is preferable that the first light-emitting material is a fluorescent light-emitting material and the second light-emitting material is a phosphorescent light-emitting material. Furthermore, when the first light-emitting layer contains the first light-emitting material, the second light-emitting layer contains the second light-emitting material, and the third light-emitting layer contains the third light-emitting material, it is preferable that the first light-emitting material is a fluorescent light-emitting material and the second light-emitting material and the third light-emitting material are phosphorescent light-emitting materials.

[0106] The phosphorescent material is not particularly limited as long as it is a compound that mainly emits phosphorescence, and examples thereof include a compound represented by the following general formula (E) and exemplary compounds BD9, GD10 to GD18, and RD3 to RD10 described below. ｍ (L') ｎ (L”) ｐ (E)

[0107] In general formula (E), M represents a metal atom. Specifically, it is an iridium atom and a platinum atom. L, L', and L" each represent a different bidentate ligand. m is selected from an integer of 1 or more and 3 or less. n and p are selected from integers of 0 or more and 2 or less, provided that m + n + p = 3. When m is 2 or more, L' may be the same or different. When n is 2 or more, L' may be the same or different. When p is 2 or more, L" may be the same or different.

[0108] M (L) ｍ is represented by the following general formula (E-1).

[0109]

[0110] In formula (E-1), Z １ ~Z ４ is C(R ２１ ), and a nitrogen atom. ２１ ~R ２８are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, or a cyano group, provided that R ２１ ~R ２８ At least one of Z is selected from a substituted or unsubstituted aryl group and a substituted or unsubstituted heteroaryl group. １ ~Z ４ is C(R ２１ ), R ２１ may be the same as or different from each other.

[0111] Also, adjacent R ２１ ~R ２８ may be bonded to each other to form a ring.

[0112] M(L') ｎ is represented by the following general formula (E-2).

[0113]

[0114] In formula (E-2), Z ５ ~Z ８ is C(R ３５ ), and a nitrogen atom. ３１ ~R ３５ are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, or a cyano group. ５ ~Z ８ is C(R ３５ ), R ３５ may be the same as or different from each other.

[0115] Also, adjacent R ３１ ~R ３５may be bonded to each other to form a ring.

[0116] M (L”) ｐ is represented by general formula (E-3).

[0117]

[0118] In formula (E-3), R ３９ ~R ４１ are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted silyl group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, and a cyano group.

[0119] The partial structure M(L) of the organometallic complex, which is a light-emitting compound, is shown below. ｍ Specific examples are shown below, but the present invention is not limited to these. In the specific examples shown below, coordinate bonds are shown by straight lines, dotted lines or arrows.

[0120]

[0121]

[0122]

[0123] In the general formulae [Ir-5] to [Ir-8], [Ir-15], and [Ir-16], X' is selected from an oxygen atom, a sulfur atom, a substituted or unsubstituted carbon atom, and a substituted or unsubstituted nitrogen atom. ２１ ~R ２８ is as described above in formula (E-1).

[0124] In the general formulas [Ir-1] to [Ir-20], adjacent R ２１ ~R ２８ may be bonded to each other to form a ring.

[0125] Specific examples of phosphorescent materials are shown below, but the present invention is not limited to these.

[0126]

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138]

[0139]

[0140]

[0141]

[0142] The fluorescent material is not particularly limited as long as it is a compound that mainly emits fluorescence, and examples thereof include compounds represented by the following general formulas (F) to (K), compounds having a plurality of structures represented by general formula (F), compounds having a plurality of structures represented by general formula (H), and exemplary compounds BD1 to BD8, BD10 to BD11, GD1 to GD9, and RD1 to RD2 described later.

[0143]

[0144] In general formulas (F) and (G), the cyclic units A to C are each independently selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. １ ~Q ３ is a direct bond, C(R Ａ ) (R Ｂ ), N(R Ｃ ), B(RＤ ), an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom. １ ~Q ３ is B(R Ｄ ) may be used. Ａ ~R Ｄ are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group. Ａ and R Ｂ may be bonded to each other to form a ring, and R Ａ may bond with adjacent cyclic units A to C to form a ring, R Ｂ and adjacent cyclic units A to C may be bonded to each other to form a ring. Ｃ may form a ring with the adjacent cyclic units A to C.

[0145]

[0146] In general formulas (H) and (I), the cyclic units A to C are each independently selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. １ ~Q ３ is a direct bond, C(R Ａ ) (R Ｂ ), N(R Ｃ ), B(R Ｄ ), an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom. １ ~Q ３ is N(R Ｃ ) may be used. Ａ ~R Ｄ are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group. Ａ and R Ｂ may be bonded to each other to form a ring, and R Ａ may bond with adjacent cyclic units A to C to form a ring, R Ｂand adjacent cyclic units A to C may be bonded to each other to form a ring. Ｃ may form a ring with the adjacent cyclic units A to C.

[0147] In the compound consisting of multiple structures represented by general formula (F), multiple structures represented by general formula (F) may be fused via ring A, multiple structures represented by general formula (F) may be fused via ring B, or multiple structures represented by general formula (F) may be fused via ring C. The same applies to the compound consisting of multiple structures represented by general formula (F). Specific examples of the compound consisting of multiple structures represented by general formula (F) include, but are not limited to, the following compounds.

[0148]

[0149] In addition, in the compound consisting of multiple structures represented by general formula (H), multiple structures represented by general formula (H) may be fused via ring A, multiple structures represented by general formula (H) may be fused via ring B, or multiple structures represented by general formula (H) may be fused via ring C. The same applies to the compound consisting of multiple structures represented by general formula (I).

[0150]

[0151] In general formula (J), the cyclic units A to E are each independently selected from a substituted or unsubstituted aryl group or a substituted or unsubstituted heteroaryl group. The cyclic units A to E may each be a substituted or unsubstituted benzene skeleton. Furthermore, the cyclic units A, B, D, and E may each be a substituted or unsubstituted benzene skeleton, and the cyclic unit C may each be a substituted or unsubstituted benzene skeleton or naphthalene skeleton. Q １ ~Q ３ is a direct bond, C(R Ａ ) (R Ｂ ), N(R Ｃ ), B(R Ｄ ), an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom. １ ~Q ４ may be a direct bond. Ａ ~RＤ are each independently selected from a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heteroaryl group.

[0152] Specific examples of the compound represented by formula (J) include, but are not limited to, the following compounds.

[0153]

[0154]

[0155] In general formula (K), R １ ~R ２０ are each independently selected from the group consisting of a hydrogen atom, a deuterium atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted silyl group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heteroaryl group, and a cyano group. １ ~R ２０ may be bonded to each other to form a ring. The bond may be via a chalcogen atom. ４ and R ５ , R ９ and R １０ , R １４ and R １５ , R １９ and R ２０ At least one of the combinations of R ９ and R １０ , R １９ and R ２０ At least one of the combinations of X is bonded to each other. １ and X ２ are each independently selected from the group consisting of a chalcogen atom, a substituted or unsubstituted imino group, a substituted or unsubstituted methylene group, and a substituted or unsubstituted silylene group.

[0156] Specific examples of general formula (K) are shown below, but the invention is not limited to these.

[0157]

[0158]

[0159]

[0160]

[0161]

[0162]

[0163] The organic light-emitting device according to this embodiment will be further described below.

[0164] <Other Materials> In the organic light-emitting element according to this embodiment, conventionally known low-molecular-weight and high-molecular-weight hole-injecting or hole-transporting compounds, host compounds, light-emitting compounds, electron-injecting or electron-transporting compounds, etc. may also be used as needed. Examples of these compounds are listed below.

[0165] As the hole injection transport material, a material with high hole mobility is preferred so that it can facilitate the injection of holes from the anode and transport the injected holes to the light-emitting layer. Furthermore, a material with a high glass transition temperature is preferred to suppress deterioration of film quality, such as crystallization, in the organic light-emitting device. Examples of low-molecular-weight and high-molecular-weight materials with hole injection and transport properties include triarylamine derivatives, arylcarbazole derivatives, phenylenediamine derivatives, stilbene derivatives, phthalocyanine derivatives, porphyrin derivatives, poly(vinylcarbazole), poly(thiophene), and other conductive polymers. Furthermore, the above-mentioned hole injection and transport materials are also suitable for use in electron blocking layers or p-type charge generating layers. Specific examples of compounds that can be used as hole injection and transport materials are shown below, but are not limited to these.

[0166]

[0167] Examples of light-emitting materials that are primarily involved in light-emitting function include fused ring compounds (e.g., fluorene derivatives, naphthalene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, anthracene derivatives, rubrene, etc.), quinacridone derivatives, coumarin derivatives, stilbene derivatives, organoaluminum complexes such as tris(8-quinolinolato)aluminum, iridium complexes, platinum complexes, rhenium complexes, copper complexes, europium complexes, ruthenium complexes, and polymer derivatives such as poly(phenylenevinylene) derivatives, poly(fluorene) derivatives, and poly(phenylene) derivatives. Specific examples of compounds that can be used as light-emitting materials are shown below, but the present invention is not limited to these.

[0168]

[0169]

[0170]

[0171]

[0172]

[0173] Examples of the host compound and assist compound contained in the first emitting layer and the second emitting layer include, but are not limited to, aromatic hydrocarbon compounds or derivatives thereof (particularly, pyrene derivatives, perylene derivatives, fluoranthene derivatives, anthracene derivatives, etc.), as well as carbazole derivatives, azine derivatives, xanthone derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, organic aluminum complexes such as tris(8-quinolinolato)aluminum, and organic beryllium complexes. Specific examples are shown below.

[0174]

[0175] The electron transport material can be arbitrarily selected from those capable of transporting electrons injected from the cathode to the light-emitting layer, and is selected taking into consideration the balance with the hole mobility of the hole transport material. Examples of materials having electron transport properties include oxadiazole derivatives, oxazole derivatives, pyrazine derivatives, triazole derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, phenanthroline derivatives, naphthyridine derivatives, organoaluminum complexes, and fused ring compounds (e.g., fluorene derivatives, naphthalene derivatives, chrysene derivatives, anthracene derivatives, etc.). Furthermore, the above electron transport materials are also suitable for use in hole blocking layers. Specific examples of compounds used as electron transport materials are shown below, but are not limited thereto. Specific examples are shown below.

[0176]

[0177] Of the above-exemplified compounds, compounds ET1 to 21, ET24 to 26, and ET29 to 30 can be suitably used as the first organic compound of the n-type charge generating layer.

[0178] The electron injection material can be arbitrarily selected from those that can easily inject electrons from the cathode, and is selected taking into consideration the balance with hole injection properties, etc. Examples of organic compounds include n-type dopants and reducing dopants. Examples include compounds containing alkali metals such as lithium fluoride, lithium complexes such as lithium quinolinol, benzimidazolidine derivatives, imidazolidine derivatives, fulvalene derivatives, and acridine derivatives. Furthermore, the electron injection material can be used in combination with the above-mentioned electron transport material.

[0179] <Configuration of Organic Light-Emitting Element> An organic light-emitting element is typically provided by forming an insulating layer, a first electrode, an organic compound layer, and a second electrode on a substrate. In the organic light-emitting element according to this embodiment, the organic compound layer is a first light-emitting unit, a charge generation layer, a second light-emitting unit, and optionally a third light-emitting unit. A protective layer, a color filter, a microlens, or the like may be provided on the second electrode. When a color filter is provided, a planarizing layer may be provided between the protective layer and the color filter. The planarizing layer may be made of an acrylic resin or the like. The same applies when a planarizing layer is provided between the color filter and the microlens.

[0180] Preferred configurations of the organic light-emitting element of the present invention and the device having the organic light-emitting element will be described below.

[0181] [Substrate] The organic light-emitting element of the present invention may be formed on a substrate, and examples of the substrate include quartz, glass, a silicon wafer, a resin, and a metal. Furthermore, the substrate may be provided with a switching element such as a transistor and wiring, and an insulating layer thereon. Any material can be used for the insulating layer, as long as it can form a contact hole so that wiring can be formed between the first electrode and the insulating layer, and can ensure insulation from wiring that is not connected. For example, resins such as polyimide, silicon oxide, silicon nitride, etc. can be used.

[0182] [Electrodes] An organic light-emitting element has a pair of electrodes, and when an electric field is applied in the direction in which the organic light-emitting element emits light, the electrode with a higher potential is the anode, and the other is the cathode. It can also be said that the electrode that supplies holes to the light-emitting layer is the anode, and the electrode that supplies electrons is the cathode. In the present invention, either the anode or the cathode may be the first electrode (substrate side). Typically, as illustrated in FIG. 1 , the first electrode 200 on the substrate 1 side is the anode, but this is not limited thereto.

[0183] The anode material should preferably have as large a work function as possible. Examples of such materials include simple metals such as gold, platinum, silver, copper, nickel, palladium, cobalt, selenium, vanadium, and tungsten, mixtures containing these metals, alloys of these metals, and metal oxides such as tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and zinc indium oxide. Conductive polymers such as polyaniline, polypyrrole, and polythiophene can also be used.

[0184] These electrode materials may be used alone or in combination of two or more. The anode may be composed of one layer or multiple layers.

[0185] When used as a reflective electrode, for example, chromium, aluminum, silver, titanium, tungsten, molybdenum, or alloys or laminates thereof can be used. The above materials can also function as a reflective film without functioning as an electrode. When used as a transparent electrode, transparent conductive oxide layers such as indium tin oxide (ITO) and indium zinc oxide can be used, but are not limited to these. Photolithography technology can be used to form the electrode.

[0186] On the other hand, materials with a low work function are preferred for the cathode. Examples include alkali metals such as lithium, alkaline earth metals such as calcium, and metals such as aluminum, titanium, manganese, silver, lead, and chromium, as well as mixtures containing these metals. Alternatively, alloys combining these metals can be used. For example, magnesium-silver, aluminum-lithium, aluminum-magnesium, silver-copper, and zinc-silver can be used. Metal oxides such as indium tin oxide (ITO) can also be used. These electrode materials can be used alone or in combination. The cathode can have either a single-layer or multi-layer structure. Among these, silver is preferred, and a silver alloy is even more preferred to reduce silver aggregation. The alloy ratio is not critical as long as silver aggregation can be reduced. For example, the silver:other metal ratio can be 1:1, 3:1, or the like.

[0187] The cathode may be a top-emission element using an oxide conductive layer such as ITO, or a bottom-emission element using a reflective electrode such as aluminum (Al), and is not particularly limited. The method for forming the cathode is not particularly limited, but DC and AC sputtering methods are more preferable because they provide good film coverage and make it easier to reduce resistance.

[0188] 1 are usually called organic compound layers, but may also include a layer composed of an inorganic compound. In addition, an insulating layer, an adhesive layer, or an interference layer may be provided at the interface between the first electrode 200 and the first light-emitting unit 300 and the interface between the second electrode 600 and the second light-emitting unit 500.

[0189] In a configuration in which a plurality of organic light-emitting elements are arranged, the organic compound layer may be formed as a common layer for the plurality of organic light-emitting elements. The common layer is disposed across the plurality of organic light-emitting elements, and can be formed by applying a coating method such as spin coating or a vapor deposition method to the entire surface of the substrate.

[0190] The organic compound layer constituting the organic light-emitting element of the present invention can be formed by dry processes such as vacuum deposition, ionization deposition, sputtering, plasma, etc. Alternatively, instead of the dry process, a wet process can be used in which a compound is dissolved in an appropriate solvent and a layer is formed by a known coating method (e.g., spin coating, dipping, casting, LB method, inkjet method, etc.).

[0191] Here, when a layer is formed by a vacuum deposition method or a solution coating method, crystallization is unlikely to occur and the layer has excellent stability over time. When a film is formed by a coating method, the film can be formed by combining with an appropriate binder resin.

[0192] Examples of the binder resin include, but are not limited to, polyvinyl carbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenol resin, epoxy resin, silicone resin, and urea resin.

[0193] These binder resins may be used singly or in combination as homopolymers or copolymers, and may further contain known additives such as plasticizers, antioxidants, and ultraviolet absorbers, if necessary.

[0194] [Protective Layer] A protective layer may be provided on the second electrode. For example, by adhering glass with a moisture absorbent to the second electrode, the intrusion of water and other contaminants into the organic compound layer can be reduced, thereby reducing the occurrence of display defects. In another embodiment, a passivation film such as silicon nitride may be provided on the second electrode to reduce the intrusion of water and other contaminants into the organic compound layer. For example, after forming the second electrode, the second electrode may be transferred to another chamber without breaking the vacuum, and a 2 μm-thick silicon nitride film may be formed by CVD to serve as a protective layer. A protective layer may be provided using atomic layer deposition (ALD) after the CVD film formation. The material of the film formed by ALD is not limited, and may be silicon nitride, silicon oxide, aluminum oxide, or the like. Silicon nitride may be further formed on the film formed by ALD by CVD. The film formed by ALD may have a thickness smaller than that of the film formed by CVD. Specifically, it may be 50% or less, or even 10% or less.

[0195] [Color Filter] A color filter may be provided on the protective layer. For example, a color filter taking into consideration the size of the organic light-emitting element may be provided on a separate substrate and then bonded to the substrate on which the organic light-emitting element is provided, or a color filter may be patterned on the protective layer described above using photolithography technology. The color filter may be made of a polymer.

[0196] [Planarization Layer] A planarization layer may be provided between the color filter and the protective layer. The planarization layer is provided for the purpose of reducing the unevenness of the underlying layer. It may also be called a material resin layer without limiting its purpose. The planarization layer may be composed of an organic compound, and may be either a low molecular weight or a high molecular weight, but is preferably a high molecular weight.

[0197] The planarizing layer may be provided above or below the color filter, and may be made of the same or different materials, such as polyvinyl carbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenol resin, epoxy resin, silicone resin, and urea resin.

[0198] [Microlens] An organic light-emitting element or an organic light-emitting device having the organic light-emitting element may have an optical component such as a microlens on its light-emitting side. The microlens may be made of acrylic resin, epoxy resin, or the like. The microlens may be intended to increase the amount of light extracted from the organic light-emitting element or organic light-emitting device or to control the direction of the extracted light. The microlens may have a hemispherical shape. When the microlens has a hemispherical shape, among the tangents to the hemisphere, there is a tangent that is parallel to the insulating layer, and the point of contact between this tangent and the hemisphere is the vertex of the microlens. The vertex of the microlens can be determined in the same way in any cross-sectional view. In other words, among the tangents to the semicircle of the microlens in the cross-sectional view, there is a tangent that is parallel to the insulating layer, and the point of contact between this tangent and the semicircle is the vertex of the microlens.

[0199] It is also possible to define the midpoint of a microlens. In the cross section of the microlens, a line segment is imagined from the point where an arc shape ends to the point where another arc shape ends, and the midpoint of this line segment can be called the midpoint of the microlens. The cross section for determining the vertex and midpoint may be a cross section perpendicular to the insulating layer.

[0200] [Counter Substrate] An counter substrate may be provided on the planarization layer. The counter substrate is called a counter substrate because it is provided at a position corresponding to the aforementioned substrate. The constituent material of the counter substrate may be the same as that of the aforementioned substrate (the substrate on the first electrode side). When the aforementioned substrate is the first substrate, the counter substrate may be the second substrate.

[0201] [Pixel Circuit] An organic light-emitting device having an organic light-emitting element may have a pixel circuit connected to the organic light-emitting element. The pixel circuit may be an active matrix type that controls the emission of a plurality of light-emitting elements independently. The active matrix type circuit may be voltage-programmed or current-programmed. The drive circuit has a pixel circuit for each pixel. The pixel circuit may have a light-emitting element, a transistor that controls the emission brightness of the light-emitting element, a transistor that controls the emission timing, a capacitor that holds the gate voltage of the transistor that controls the emission brightness, and a transistor for connecting to GND without going through the light-emitting element.

[0202] The light-emitting device has a display region and a peripheral region arranged around the display region. The display region has a pixel circuit, and the peripheral region has a display control circuit. The mobility of a transistor constituting the pixel circuit may be smaller than the mobility of a transistor constituting the display control circuit. The slope of the current-voltage characteristics of the transistor constituting the pixel circuit may be smaller than the slope of the current-voltage characteristics of the transistor constituting the display control circuit. The slope of the current-voltage characteristics can be measured by the so-called Vg-Ig characteristics. The transistor constituting the pixel circuit is a transistor connected to a light-emitting element, such as a first light-emitting element.

[0203] [Pixel] An organic light-emitting device having an organic light-emitting element may have a plurality of pixels. Each pixel has sub-pixels that emit different colors. The sub-pixels may each emit RGB light, for example.

[0204] A pixel has an area, also called a pixel aperture, from which light is emitted. The pixel aperture may be 15 μm or less, or 5 μm or more. More specifically, it may be 11 μm, 9.5 μm, 7.4 μm, 6.4 μm, etc. The distance between subpixels may be 10 μm or less, more specifically, it may be 8 μm, 7.4 μm, or 6.4 μm.

[0205] The pixels may be arranged in a known manner in a plan view. For example, they may be in a stripe arrangement, a delta arrangement, a pentile arrangement, or a Bayer arrangement. The shape of the subpixels in a plan view may be any known shape. For example, they may be rectangular, quadrilaterals such as diamonds, or hexagons. Of course, a shape that is close to a rectangle, rather than an exact shape, is included in the rectangle. The shape of the subpixels and the pixel arrangement may be used in combination.

[0206] The organic light-emitting device according to this embodiment can be used as a component of a display device or a lighting device. Other applications include an exposure light source for an electrophotographic image forming device, a backlight for a liquid crystal display device, and a light-emitting device having a white light source and a color filter.

[0207] The display device may be an image information processing device that has an image input unit that inputs image information from an area CCD, a linear CCD, a memory card, etc., has an information processing unit that processes the input information, and displays the input image on a display unit. The display device may have a plurality of pixels, at least one of which has the organic light-emitting element according to this embodiment and a transistor connected to the organic light-emitting element.

[0208] The display unit of the imaging device or inkjet printer may have a touch panel function. The driving method of this touch panel function may be an infrared method, a capacitance method, a resistive film method, or an electromagnetic induction method, and is not particularly limited. The display device may also be used in the display unit of a multifunction printer.

[0209] Next, the display device according to this embodiment will be described with reference to the drawings.

[0210] 2A and 2B are cross-sectional views showing examples of a display device having an organic light-emitting element according to this embodiment and a transistor connected to the organic light-emitting element.

[0211] 2A shows an example of a pixel, which is a component of the display device according to this embodiment. The pixel includes subpixels 20. The subpixels are divided into 20R, 20G, and 20B based on their light emission. The emitted colors may be distinguished by the wavelength of light emitted from the light-emitting layer, or the light emitted from the subpixels may be selectively transmitted or color-converted using a color filter or the like. Each subpixel includes a first electrode 12, which serves as a reflective electrode, on an interlayer insulating layer 11, an insulating layer 13 covering the edges of the first electrode 12, an organic compound layer 14 covering the first electrode 12 and the insulating layer 13, a second electrode 15, a protective layer 16, and a color filter 17. The first electrode 12, the organic compound layer 14, and the second electrode 15 constitute an organic light-emitting element 18 according to this embodiment.

[0212] A transistor and a capacitor may be disposed below or inside the interlayer insulating layer 11. The transistor and the first electrode 12 may be electrically connected via a contact hole or the like (not shown).

[0213] The insulating layer 13 is also called a bank or a pixel separation film. It covers the ends of the first electrodes 12 and is disposed to surround the first electrodes 12. The portions where the insulating layer 13 is not disposed are in contact with the organic compound layer 14 and become light-emitting regions.

[0214] The second electrode 15 may be a transparent electrode, a reflective electrode, or a semi-transparent electrode.

[0215] The protective layer 16 reduces the penetration of moisture into the organic compound layer 14. Although the protective layer 16 is illustrated as being a single layer, it may be a multi-layer layer, and each layer may be an inorganic compound layer and an organic compound layer.

[0216] The color filters 17 are divided into 17R, 17G, and 17B depending on their colors. The color filters may be formed on a planarization film (not shown). A resin protective layer (not shown) may be provided on the color filters. The color filters 17 may be formed on a protective layer 16. Alternatively, the color filters 17 may be provided on an opposing substrate such as a glass substrate and then bonded thereto.

[0217] 2B has an organic light-emitting element 36 and a TFT 28 as an example of a transistor. Specifically, a substrate 21 made of glass, silicon, or the like is provided with an insulating layer 22 on top of it, and a TFT 28 having a gate electrode 23, a gate insulating film 24, a semiconductor layer 25, a drain electrode 26, and a source electrode 27 is disposed on the insulating layer 22. An insulating film 29 is provided on top of the TFT 28, and an anode 31 constituting the organic light-emitting element 36 and the source electrode 27 are connected via a contact hole 30 provided in the insulating film 29.

[0218] The electrical connection between the electrodes (anode 31, cathode 33) included in the organic light-emitting element 36 and the electrodes (source electrode 27, drain electrode 26) included in the TFT 28 is not limited to the mode shown in Fig. 2B. In other words, it is sufficient that either the anode 31 or the cathode 33 is electrically connected to either the source electrode 27 or the drain electrode 26. The TFT 28 refers to a thin film transistor.

[0219] A first protective layer 34 and a second protective layer 35 are provided on the cathode 33 to reduce deterioration of the organic light-emitting element.

[0220] The organic light emitting element 36 according to this embodiment has its light emission brightness controlled by the TFT 28, and by providing a plurality of organic light emitting elements 36 on a surface, an image can be displayed with the respective light emission brightnesses.

[0221] Although the display device of FIG. 2B uses transistors as switching elements, other switching elements may be used instead.

[0222] 2B is not limited to a TFT having an active layer on an insulating surface of a substrate, but may be a transistor using a single-crystal silicon wafer. The active layer may be made of non-single-crystal silicon such as amorphous silicon or microcrystalline silicon, or a non-single-crystal oxide semiconductor such as indium zinc oxide or indium gallium zinc oxide.

[0223] Alternatively, the transistor may be formed from low-temperature polysilicon, or an active matrix driver formed on a substrate such as a Si substrate. "On a substrate" can also mean "within the substrate." Whether to provide a transistor within the substrate or use a TFT is determined by the size of the display unit. For example, for a display size of about 0.5 inches, it is preferable to provide an organic light-emitting element on a Si substrate. Here, "formed within the substrate" means that the substrate itself, such as a Si substrate, is processed to fabricate the transistor. In other words, having a transistor within a substrate can be considered as the substrate and the transistor being integrally formed.

[0224] 3 is a schematic diagram showing an example of a display device according to this embodiment. The display device 1000 has a touch panel 1003, a display panel 1005, a frame 1006, a circuit board 1007, and a battery 1008 between an upper cover 1001 and a lower cover 1009. The touch panel 1003 and the display panel 1005 are connected by flexible printed circuits FPCs 1002 and 1004. Transistors are printed on the circuit board 1007. The battery 1008 may not be provided if the display device is not a portable device, and may be provided in a different position even if the display device is a portable device.

[0225] The display device according to this embodiment may have color filters having red, green, and blue colors, and the red, green, and blue colors may be arranged in a delta configuration in the color filters.

[0226] The display device according to the present embodiment is used as a display unit of a mobile terminal. In this case, the display device may have both a display function and an operation function. Examples of the mobile terminal include a mobile phone such as a smartphone, a tablet, and a head-mounted display.

[0227] The display device according to this embodiment is used in a display unit of an imaging device having an optical unit with multiple lenses and an imaging element that receives light that has passed through the optical unit. The imaging device may have a display unit that displays information acquired by the imaging element. The display unit may be a display unit exposed to the outside of the imaging device or a display unit located within the viewfinder. The imaging device may be a digital camera or a digital video camera.

[0228] 4A is a schematic diagram showing an example of an imaging device according to this embodiment. The imaging device 1100 has a viewfinder 1101, a rear display 1102, an operation unit 1103, and a housing 1104. The viewfinder 1101 has a display device according to this embodiment. In this case, the display device may display not only an image to be captured, but also environmental information, imaging instructions, and the like. The environmental information may include the intensity of external light, the direction of external light, the speed at which the subject is moving, the possibility that the subject will be blocked by an obstruction, and the like.

[0229] Since the optimum timing for capturing an image is very short, it is better to display information as soon as possible. Therefore, it is preferable to use a display device using the organic light-emitting element according to this embodiment. This is because the organic light-emitting element has a fast response speed. A display device using the organic light-emitting element can be used more preferably than a liquid crystal display device, which requires a high display speed.

[0230] The imaging device 1100 has an optical section (not shown). The optical section has multiple lenses, which form an image on an imaging element housed in a housing 1104. The focus of the multiple lenses can be adjusted by adjusting their relative positions. This operation can also be performed automatically. The imaging device may also be called a photoelectric conversion device. Instead of sequentially capturing images, the photoelectric conversion device may include an imaging method that detects the difference from the previous image, or a method of cutting out an image that is constantly being recorded.

[0231] FIG. 4B is a schematic diagram illustrating an example of an electronic device according to this embodiment. The electronic device 1200 has a display unit 1201, an operation unit 1202, and a housing 1203. The housing 1203 may have a circuit, a printed circuit board having the circuit, a battery, and a communication unit. The operation unit 1202 may be a button or a touch panel type reaction unit. The operation unit may be a biometric recognition unit that recognizes a fingerprint to unlock the device, etc. An electronic device having a communication unit may also be called a communication device. The electronic device may further have a camera function by including a lens and an image sensor. An image captured by the camera function is displayed on the display unit. Examples of the electronic device include a smartphone and a laptop computer.

[0232] 5A and 5B are schematic diagrams illustrating an example of a display device according to this embodiment. FIG. 5A illustrates a display device such as a television monitor or a PC monitor. The display device 1300 includes a frame 1301 and a display unit 1302. The display unit 1302 uses the light-emitting device according to this embodiment. The display device 1300 includes the frame 1301 and a base 1303 that supports the display unit 1302. The base 1303 is not limited to the form shown in FIG. 5A . The lower side of the frame 1301 may also serve as the base. The frame 1301 and the display unit 1302 may be curved. The radius of curvature may be 5000 mm or more and 6000 mm or less.

[0233] FIG. 5B is a schematic diagram illustrating another example of a display device according to the present embodiment. The display device 1310 in FIG. 5B is configured to be bendable, and is a so-called foldable display device. The display device 1310 includes a first display unit 1311, a second display unit 1312, a housing 1313, and a bending point 1314. The first display unit 1311 and the second display unit 1312 include a light-emitting device according to the present embodiment. The first display unit 1311 and the second display unit 1312 may be a single, seamless display device. The first display unit 1311 and the second display unit 1312 can be separated by the bending point. The first display unit 1311 and the second display unit 1312 may each display different images, or the first and second display units may display a single image.

[0234] 6A is a schematic diagram illustrating an example of an illumination device according to this embodiment. The illumination device 1400 includes a housing 1401, a light source 1402, a circuit board 1403, an optical filter 1404, and a light diffusion unit 1405. The light source 1402 includes an organic light-emitting element according to this embodiment. The optical filter 1404 may be a filter that improves the color rendering of the light source. The light diffusion unit 1405 can effectively diffuse light from the light source 1402, such as for illumination, and deliver the light over a wide area. The optical filter 1404 and the light diffusion unit 1405 may be provided on the light output side of the illumination device. If necessary, a cover may be provided on the outermost surface.

[0235] The lighting device is, for example, a device that illuminates a room. The lighting device may emit white, daylight white, or any other color from blue to red. It may have a dimming circuit that dims these colors. The lighting device has an organic light-emitting element according to this embodiment and a power supply circuit connected to it. The power supply circuit is a circuit that converts AC voltage into DC voltage. Furthermore, white has a color temperature of 4200K, and daylight white has a color temperature of 5000K. The lighting device may have a color filter.

[0236] The lighting device according to this embodiment may also include a heat dissipation unit, which dissipates heat from within the device to the outside, and may be made of a material such as metal or liquid silicone with a high specific heat.

[0237] 6B is a schematic diagram of an automobile, which is an example of a moving body according to this embodiment. The automobile has tail lamps, which are an example of a lighting device. The automobile 1500 has tail lamps 1501, and may be configured to turn on the tail lamps when braking or the like is performed.

[0238] The tail lamp 1501 includes the organic light-emitting element according to this embodiment. The tail lamp 1501 may include a protective member for protecting the organic light-emitting element. The protective member may be made of any material as long as it has a certain degree of strength and is transparent, but is preferably made of polycarbonate or the like. Polycarbonate may be mixed with a furandicarboxylic acid derivative, an acrylonitrile derivative, or the like.

[0239] The automobile 1500 may have a body 1503 and a window 1502 attached thereto. The window 1502 may be a transparent display as long as it is not a window for checking the front and rear of the automobile. The transparent display may have the organic light-emitting element according to this embodiment. In this case, the constituent materials of the electrodes and the like of the organic light-emitting element are made of transparent materials.

[0240] The moving body according to this embodiment may be a ship, an aircraft, a drone, or the like. The moving body has a body and a lighting device provided on the body. The lighting device emits light to indicate the position of the body. The lighting device has the organic light-emitting element according to this embodiment.

[0241] 7A and 7B , application examples of the display devices according to the above-described embodiments will be described. The display device can be applied to systems that can be worn as wearable devices, such as smart glasses, HMDs, and smart contact lenses. The image capturing and display device used in such application examples includes an image capturing device capable of photoelectrically converting visible light and a display device capable of emitting visible light.

[0242] 7A illustrates glasses 1600 (smart glasses) according to one application example. An imaging device 1602 such as a CMOS sensor or a SPAD is provided on the front side of a lens 1601 of the glasses 1600. Furthermore, a display device according to any of the above-described embodiments is provided on the back side of the lens 1601.

[0243] The glasses 1600 further include a control device 1603. The control device 1603 functions as a power source that supplies power to the image capture device 1602 and the display device according to each embodiment. The control device 1603 also controls the operations of the image capture device 1602 and the display device. The lens 1601 is formed with an optical system for focusing light onto the image capture device 1602.

[0244] FIG. 7B illustrates glasses 1610 (smart glasses) according to one application example. The glasses 1610 include a control device 1612, which is equipped with an imaging device corresponding to the imaging device 1602 in FIG. 7A and a display device. A lens 1611 includes an optical system for projecting light emitted from the imaging device and the display device within the control device 1612, and an image is projected onto the lens 1611. The control device 1612 functions as a power source for supplying power to the imaging device and the display device, and controls the operation of the imaging device and the display device. The control device 1612 may also include a gaze detection unit for detecting the wearer's gaze. Infrared light may be used for gaze detection. The infrared light emitter emits infrared light toward the eyeball of a user gazing at a displayed image. An imaging unit with a light-receiving element detects the reflected light of the emitted infrared light from the eyeball, thereby obtaining an image of the eyeball. By including a reduction unit for reducing light from the infrared light emitter to the display unit in a planar view, degradation of image quality is reduced.

[0245] The user's line of sight with respect to the displayed image is detected from an image of the eyeball obtained by capturing infrared light. Any known method can be applied to gaze detection using an image of the eyeball. As an example, a gaze detection method based on a Purkinje image formed by reflection of irradiated light on the cornea can be used. More specifically, gaze detection processing is performed based on the pupil-corneal reflex method. Using the pupil-corneal reflex method, a gaze vector representing the direction (rotation angle) of the eyeball is calculated based on the image of the pupil and the Purkinje image included in the image of the eyeball, thereby detecting the user's gaze.

[0246] The display device according to this embodiment may include an imaging device having a light-receiving element, and may control the display image of the display device based on user line-of-sight information from the imaging device. Specifically, the display device determines a first field of view area where the user gazes and a second field of view area other than the first field of view area based on the line-of-sight information. The first field of view area and the second field of view area may be determined by a control device of the display device, or may be determined by an external control device and received. In the display area of ​​the display device, the display resolution of the first field of view area may be controlled to be higher than the display resolution of the second field of view area. In other words, the resolution of the second field of view area may be lower than that of the first field of view area.

[0247] The display area may include a first display area and a second display area different from the first display area, and a high-priority area may be determined from the first display area and the second display area based on line-of-sight information. The first and second field-of-view areas may be determined by a control device of the display device, or may be determined by an external control device and received. The resolution of the high-priority area may be controlled to be higher than the resolution of areas other than the high-priority area. In other words, the resolution of an area with a relatively low priority may be lowered.

[0248] Note that AI may be used to determine the first field of view area and areas with high priority. The AI ​​may be a model configured to estimate the angle of gaze and the distance to an object in the line of sight from the image of the eyeball, using as training data an image of the eyeball and the direction in which the eyeball in the image was actually looking. The AI ​​program may be included in the display device, the imaging device, or an external device. If included in the external device, it is transmitted to the display device via communication.

[0249] When display control is performed based on visual recognition detection, the smart glasses can be preferably applied to smart glasses that further include an imaging device for capturing images of the outside world. The smart glasses can display captured external information in real time.

[0250] 8A is a schematic diagram showing an example of an image forming apparatus according to one embodiment of the present invention. The image forming apparatus 1700 is an electrophotographic image forming apparatus and includes a photoconductor 1707, an exposure light source 1708, a charging unit 1710, a developing unit 1711, a transfer unit 1712, transport rollers 1713, and a fixing unit 1715. Light 1709 is irradiated from the exposure light source 1708, and an electrostatic latent image is formed on the surface of the photoconductor 1707. The exposure light source 1708 includes an organic light-emitting element according to this embodiment. The developing unit 1711 includes toner and the like. The charging unit 1710 charges the photoconductor 1707. The transfer unit 1712 transfers the developed image to a recording medium 1714. The transport rollers 1713 transport the recording medium 1714. The recording medium 1714 is, for example, paper. The fixing unit 1715 fixes the image formed on the recording medium 1714.

[0251] 8B and 8C are diagrams showing an exposure light source 1708 and are schematic diagrams illustrating a state in which multiple light-emitting units 1726 are arranged on a long substrate. Arrow 1727 is a direction parallel to the axis of the photoconductor and represents the column direction in which the organic light-emitting elements are arranged. This column direction is the same as the axis direction about which the photoconductor 1707 rotates. This direction can also be referred to as the long axis direction of the photoconductor 1707. FIG. 8B shows a configuration in which the light-emitting units 1726 are arranged along the long axis direction of the photoconductor 1707. The light-emitting units 1726 include organic light-emitting elements according to this embodiment. FIG. 8C shows a configuration different from FIG. 8B , in which the light-emitting units 1726 are alternately arranged in the column direction in each of the first and second columns. The first and second columns are arranged at different positions in the row direction. In the first column, multiple light-emitting units 1726 are arranged at intervals. The second column has light-emitting units 1726 at positions corresponding to the spacing between the light-emitting units 1726 in the first column. That is, the light-emitting units 1726 are also arranged at intervals in the row direction. The arrangement in Fig. 8C can also be described as, for example, a grid-like arrangement, a houndstooth arrangement, or a checkerboard pattern.

[0252] As described above, by using a device using the organic light-emitting element according to this embodiment, it is possible to provide a stable display with good image quality even over a long period of time.

[0253] [Configurations Included] The disclosure of this embodiment includes the following configurations.

[0254] (Structure 1) An organic light-emitting device comprising a first electrode, a first light-emitting unit, a charge generating layer, a second light-emitting unit, and a second electrode in this order, the first light-emitting unit comprising a first organic layer, a first light-emitting layer, and a second organic layer adjacent to one another in this order, the first organic layer comprising an organic compound A, the first light-emitting layer comprising an organic compound B, and the second organic layer comprising an organic compound C, wherein the relationship represented by the following formula [1] is satisfied: ΔLUMO1≧0 [1] ΔLUMO1=LUMO(C)−LUMO(B), where LUMO(B): LUMO level of organic compound B, and LUMO(C): LUMO level of organic compound C.

[0255] (Configuration 2) The organic light-emitting device according to claim 1, wherein the organic light-emitting device satisfies the relationship represented by the following formula [1-1]: ΔHOMO1<ΔLUMO1 and ΔLUMO1≧0 [1-1] ΔHOMO1=HOMO(B)−HOMO(A), where HOMO(A): HOMO level of organic compound A, HOMO(B): HOMO level of organic compound B.

[0256] (Structure 3) The organic light-emitting element according to Structure 1 or 2, wherein the second light-emitting unit has a third organic layer, a second light-emitting layer, a third light-emitting layer, and a fourth organic layer in this order, the third organic layer and the second light-emitting layer, and the third light-emitting layer and the fourth organic layer are adjacent to each other, and the third light-emitting layer has an organic compound F and an organic compound H, and the relationship represented by the following formula [2] is satisfied: HOMO(H)<HOMO(F) [2] HOMO(F): HOMO level of organic compound F HOMO(H): HOMO level of organic compound H

[0257] (Structure 4) The organic light-emitting element according to any one of Structures 1 to 3, wherein the second light-emitting unit has a third organic layer, a second light-emitting layer, a third light-emitting layer, and a fourth organic layer in this order, the third organic layer and the second light-emitting layer, and the third light-emitting layer and the fourth organic layer are adjacent to each other, and the third light-emitting layer has an organic compound F and an organic compound H, and the relationship represented by the following formula [3] is satisfied: LUMO(F)<LUMO(H) [3] LUMO(F): LUMO level of organic compound F LUMO(H): LUMO level of organic compound H

[0258] (Configuration 5) The organic light-emitting device according to Configuration 4, wherein the third light-emitting layer satisfies the relationship represented by the following formula [3-1]: LUMO(H)-LUMO(F)≧0.2 eV [3-1]

[0259] (Structure 6) The organic light-emitting element according to any one of Structures 3 to 5, wherein the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer contain a fluorescent material.

[0260] (Structure 7) The organic light-emitting element according to any one of Structures 3 to 5, wherein the first light-emitting layer contains a fluorescent material, and the second light-emitting layer and the third light-emitting layer contain phosphorescent materials.

[0261] (Configuration 8) The organic light-emitting element according to any one of Configurations 1 to 7, wherein the first light-emitting layer contains a compound in which all of the freely rotatable bonds are made of carbon.

[0262] (Configuration 9) The organic light-emitting device according to any one of Configurations 1 to 8, wherein the first light-emitting layer contains a material that assists hole trapping.

[0263] (Structure 10) The organic light-emitting device according to any one of Structures 1 to 9, wherein the first light-emitting layer contains at least one selected from the group consisting of pyrene derivatives, perylene derivatives, anthracene derivatives, and fluoranthene derivatives.

[0264] (Configuration 11) A display device comprising: a display unit having the organic light-emitting element according to any one of configurations 1 to 10; and a housing in which the display unit is provided.

[0265] (Configuration 12) A photoelectric conversion device comprising: an imaging element that receives light; and a display unit that displays an image captured by the imaging element, wherein the display unit has the organic light-emitting element according to any one of configurations 1 to 10.

[0266] (Configuration 13) An electronic device comprising: a display unit having the organic light-emitting element according to any one of Configurations 1 to 10; a housing in which the display unit is provided; and a communication unit provided in the housing and communicating with an external device.

[0267] (Configuration 14) A wearable device comprising: a display unit having the organic light-emitting element according to any one of Configurations 1 to 10; an optical system that focuses light from the display unit; and a control device that controls display on the display unit.

[0268] (Configuration 15) A lighting device comprising: a light source having the organic light-emitting element according to any one of Configurations 1 to 10; and a housing in which the light source is provided.

[0269] (Configuration 16) A moving body comprising: a lighting fixture having the organic light-emitting element according to any one of configurations 1 to 10; and a vehicle on which the lighting fixture is provided.

[0270] (Configuration 17) An image forming apparatus comprising: a photosensitive member; and an exposure light source for exposing the photosensitive member, the exposure light source comprising the organic light-emitting element according to any one of claims 1 to 10.

[0271] Examples are shown below, but the present invention is not limited to the following contents.

[0272] In this example, a top-emission stacked organic light-emitting device was fabricated by sequentially forming an anode as a first electrode, a first light-emitting unit, a charge generating layer, a second light-emitting unit, and a cathode as a second electrode on a substrate. An organic light-emitting device with a double-sided emission structure was fabricated by sequentially forming a blue light-emitting layer for the first light-emitting unit and a yellow light-emitting layer for the second light-emitting unit.

[0273] First, an ITO film was formed on a glass substrate and then patterned as desired to form an ITO electrode (anode). The ITO electrode had a thickness of 100 nm. The substrate on which the ITO electrode was formed was used as an ITO substrate. Next, a first light-emitting unit, a charge-generating layer, a second light-emitting unit, and a cathode were formed in this order on the ITO substrate by vacuum deposition using resistance heating in a vacuum chamber. Note that, at this time, the electrode areas of the opposing electrodes (anode and cathode) were 3 mm2. ２ After the layers up to the cathode were formed, the substrate was transferred to a glove box and sealed with a glass cap containing a desiccant in a nitrogen atmosphere, to obtain a stacked organic light-emitting device.

[0274]

[0275] (Examples 2 to 13, Comparative Examples 1 to 4) Organic light-emitting devices were fabricated in the same manner as in Example 1, except that the various organic compounds used in the first light-emitting unit and the second light-emitting unit were changed to the compounds listed in Table 6. In Example 6, an organic light-emitting device was fabricated in the same manner as in Example 1, except that the configuration was changed to that listed in Table 4. Table 5 shows the HOMO and LUMO values ​​of the compounds used in these examples and comparative examples. The unit is "eV".

[0276] In addition, "ΔLUMO3" in Table 6 is the value of "LUMO(H)-LUMO(F)".

[0277]

[0278] (Evaluation) The voltage-current characteristics of the obtained organic light-emitting devices were measured using a microcurrent meter 4140B manufactured by Hewlett-Packard, and the emission spectrum was measured using an SR-3 manufactured by Topcon. The organic light-emitting devices of Examples 1 to 13 exhibited good white light emission. ２ A drive test of the organic light-emitting device was performed under a constant current condition of 1.0 V, and the LT80, which is the time it takes for the luminance to deteriorate by 20% from the initial luminance, and the drive voltage were evaluated. The results are shown in Table 6. The voltage ratio and durability ratio values ​​are relative values ​​when the LT80 and voltage of Comparative Example 1 are set to 1.0.

[0279]

[0280]

[0281] As can be seen from Table 6, in Examples 1 to 2 and 9 to 11, the first light-emitting layer between the charge generation layer and the anode has a good electron injection property, so that electrons generated from the charge generation layer are smoothly injected into the light-emitting layer in the first light-emitting unit. Injecting electrons into the light-emitting layer without stagnation around the charge generation layer improves durability and simultaneously achieves high efficiency.

[0282] Furthermore, a comparison between Examples 1 and 3 shows that when the second light-emitting unit has superior hole injection properties, holes generated from the charge generation layer are smoothly injected into the second light-emitting layer of the second light-emitting unit, which is an upper layer than the charge generation layer, leading to improved durability and efficiency.

[0283] Furthermore, a comparison between Examples 1 and 4 shows that the electron trapping property of the third light-emitting layer leads to the recombination of holes generated from the charge generating layer closer to the cathode side, enabling the holes to be injected into the third light-emitting layer without stagnation, which in turn leads to the suppression of charge accumulation, which in turn leads to the suppression of deterioration of the layers surrounding the light-emitting layer, thereby improving durability.

[0284] Furthermore, as shown in Examples 1 to 2 and 9 to 11, when a pyrene derivative, a perylene derivative, an anthracene derivative, or a fluoranthene derivative is used as organic compound B in the first light-emitting layer, the electron mobility is higher and electrons can be migrated more quickly from the charge generation layer, compared to when a compound other than the above is used as organic compound B in the first light-emitting layer as in Example 12. This makes it possible to suppress charge accumulation and improve durability, thereby enabling the effects of the present invention to be more effectively exhibited.

[0285] Furthermore, when a compound in which all of the freely rotatable bonds are composed of carbon is used as organic compound B in the first light-emitting layer as shown in Example 1, the bond energy is high and the structure is stable, and durability is improved, compared to when a compound other than the above is used as organic compound B in the first light-emitting layer as shown in Example 7, and therefore the effects of the present invention can be more effectively exhibited.

[0286] On the other hand, in Comparative Examples 1 to 4, the first light-emitting layer of the first light-emitting unit does not have good electron injection properties, and electrons from the charge generation layer remain, leading to deterioration of the surrounding layers, thereby reducing the durability of the light-emitting element.

[0287] The present invention is not limited to the above-described embodiments, and various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, the following claims are appended to apprise the public of the scope of the present invention.

[0288] This application claims priority based on Japanese Patent Application No. 2024-034331, filed March 6, 2024, the entire contents of which are incorporated herein by reference.

[0289] 200 First electrode 300 First light-emitting unit 303 First organic layer 304 First light-emitting layer 305 Second organic layer 400 Charge generation layer 500 Second light-emitting unit 502 Third organic layer 503 Second light-emitting layer 504 Fourth organic layer 600 Second electrode 1000, 1300, 1310 Display device 1100 Imaging device 1104, 1203, 1313 Housing 1200 Electronic device 1201 Display section 1302, 1311, 1312 Display section 1707 Photoconductor 1708 Exposure light source

Claims

1. An organic light-emitting device comprising a first electrode, a first light-emitting unit, a charge generating layer, a second light-emitting unit, and a second electrode in this order, the first light-emitting unit comprising a first organic layer, a first light-emitting layer, and a second organic layer adjacent to one another in this order, the first organic layer comprising organic compound A, the first light-emitting layer comprising organic compound B, and the second organic layer comprising organic compound C, satisfying the relationship represented by the following formula [1]: ΔLUMO1≧0 [1] ΔLUMO1=LUMO(C)−LUMO(B), LUMO(B): LUMO level of organic compound B, LUMO(C): LUMO level of organic compound C.

2. The organic light-emitting device according to claim 1, wherein the organic light-emitting device satisfies the relationship represented by formula [1-1]: ΔHOMO1<ΔLUMO1 and ΔLUMO1≧0 [1-1] ΔHOMO1=HOMO(B)−HOMO(A), where HOMO(A): HOMO level of organic compound A, HOMO(B): HOMO level of organic compound B.

3. The organic light-emitting device according to claim 1 or 2, characterized in that the second light-emitting unit has a third organic layer, a second light-emitting layer, a third light-emitting layer, and a fourth organic layer in this order, the third organic layer and the second light-emitting layer, and the third light-emitting layer and the fourth organic layer are adjacent to each other, and the third light-emitting layer has an organic compound F and an organic compound H, and the relationship represented by the following formula [2] is satisfied: HOMO(H)<HOMO(F) [2] HOMO(F): HOMO level of organic compound F HOMO(H): HOMO level of organic compound H 4. The organic light-emitting device according to claim 1 or 2, characterized in that the second light-emitting unit has a third organic layer, a second light-emitting layer, a third light-emitting layer, and a fourth organic layer in this order, the third organic layer and the second light-emitting layer, and the third light-emitting layer and the fourth organic layer are adjacent to each other, and the third light-emitting layer has an organic compound F and an organic compound H, and the relationship represented by the following formula [3] is satisfied: LUMO(F)<LUMO(H) [3] LUMO(F): LUMO level of organic compound F LUMO(H): LUMO level of organic compound H 5. The organic light-emitting element according to claim 4, wherein the third light-emitting layer satisfies the relationship represented by the following formula [3-1]: LUMO(H)-LUMO(F)≧0.2 eV [3-1] 6. The organic light-emitting device according to claim 3, wherein the first light-emitting layer, the second light-emitting layer, and the third light-emitting layer contain fluorescent light-emitting materials.

7. The organic light-emitting element according to claim 3, wherein the first light-emitting layer contains a fluorescent light-emitting material, and the second light-emitting layer and the third light-emitting layer contain phosphorescent light-emitting materials.

8. The organic light-emitting device according to claim 1 or 2, wherein the first light-emitting layer contains a compound in which all of the freely rotatable bonds are carbon.

9. The organic light-emitting element according to claim 1 or 2, wherein the first light-emitting layer contains a material that assists hole trapping.

10. The organic light-emitting element according to claim 1 or 2, wherein the first light-emitting layer contains at least one selected from the group consisting of pyrene derivatives, perylene derivatives, anthracene derivatives, and fluoranthene derivatives.

11. A display device comprising: a display unit having the organic light-emitting element according to claim 1 or 2; and a housing in which the display unit is provided.

12. A photoelectric conversion device comprising an image sensor that receives light and a display unit that displays an image captured by said image sensor, wherein said display unit comprises the organic light-emitting element according to claim 1 or 2.

13. An electronic device comprising: a display unit having the organic light-emitting element according to claim 1 or 2; a housing in which the display unit is provided; and a communication unit provided in the housing for communicating with the outside.

14. A wearable device comprising a display unit having the organic light-emitting element according to claim 1 or 2, an optical system for focusing light from the display unit, and a control device for controlling the display of the display unit.

15. A lighting device comprising a light source having the organic light-emitting element according to claim 1 or 2, and a housing in which the light source is provided.

16. A moving object comprising a lighting fixture having the organic light-emitting element according to claim 1 or 2, and a vehicle on which the lighting fixture is mounted.

17. An image forming apparatus comprising a photosensitive member and an exposure light source for exposing said photosensitive member, said exposure light source comprising the organic light-emitting element according to claim 1 or 2.

Images