Organic compound and organic light-emitting device

Abstract

To provide an organic compound that has high light-emitting efficiency.SOLUTION: An organic compound is represented by a general formula [1] or [2], where X1 to X18 and X21 to X38 are each independently selected from a hydrogen atom, a halogen atom, an alkyl group and the like, Y is selected from oxygen, sulfur, selenium, tellurium, a carbonyl group and the like, and Z denotes one of an alkyl group, an aryl group, and a heterocyclic group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an organic compound and an organic light-emitting device using the same. [Background technology]

[0002] An organic light-emitting device (hereinafter sometimes referred to as an "organic electroluminescence device" or "organic EL device") is an electronic device having a pair of electrodes and an organic compound layer disposed between the electrodes. By injecting electrons and holes from the pair of electrodes, excitons of a light-emitting organic compound in the organic compound layer are generated, and when the excitons return to the ground state, the organic light-emitting device emits light. Recent advances in organic light-emitting devices have been remarkable, including low driving voltage, diverse emission wavelengths, high-speed response, and the possibility of thinning and reducing the weight of light-emitting devices. In order to improve the efficiency of light-emitting elements, elements using high-efficiency materials such as phosphorescent materials and delayed fluorescent materials can be mentioned. Patent Document 1 describes the following compound A-1. Non-Patent Document 1 describes the following compound A-2.

[0003] [ka] [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2017 / 092476 [Non-patent literature]

[0005] [Non-Patent Document 1] Chemistry of Materials(2018),30(3),857-863 Summary of the Invention [Problem to be solved by the invention]

[0006] When the compounds A-1 and A-2 described in Patent Document 1 and Non-Patent Document 1 are used in the light-emitting layer of an organic light-emitting device, there is a problem with the luminous efficiency. The present invention has been made to solve the above problems, and an object of the present invention is to provide an organic compound and an organic light-emitting device having excellent luminous efficiency. Another object of the present invention is to provide an organic light-emitting device having excellent luminous efficiency and driving durability. [Means for solving the problem]

[0007] The organic compound of the present invention is characterized by being represented by the following general formula [1] or [2].

[0008] [ka] In formula [1] or [2], X1 to X 18 , X 21 ~X 38 are each independently selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a silyl group. 18 , X 21 ~X 38 In the above, when the alkyl group or the aryl group has a substituent, the substituent is preferably a halogen atom, an alkyl group, or Aryl Based on be. Y represents oxygen, sulfur, selenium, tellurium, a CRR group, or a carbonyl group. R1 and R2 are each independently selected from a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a silyl group. In R1 and R2, when the alkyl group or the aryl group has a substituent, the substituent is preferably a halogen atom, an alkyl group, or Aryl Based on be. Z represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group. [Effects of the Invention]

[0009] The organic compound according to the present invention is less likely to cause molecular association and can reduce concentration quenching, so that when the organic compound according to the present invention is used in an organic light-emitting element, an organic light-emitting element having excellent luminous efficiency and driving durability can be provided. [Brief explanation of the drawings]

[0010] [Figure 1] 1A is a schematic cross-sectional view showing an example of a pixel of a display device according to one embodiment of the present invention, and FIG. 1B is a schematic cross-sectional view showing an example of a display device using an organic light-emitting element according to one embodiment of the present invention. [Figure 2] 1A is a schematic diagram illustrating an example of an image forming apparatus according to an embodiment of the present invention, and FIG. 1B is a schematic diagram illustrating an example of an exposure light source of the image forming apparatus according to an embodiment of the present invention. [Figure 3] 1 is a schematic diagram illustrating an example of a display device according to an embodiment of the present invention. [Figure 4] 1A is a schematic diagram illustrating an example of an imaging device according to an embodiment of the present invention, and FIG. 1B is a schematic diagram illustrating an example of an electronic device according to an embodiment of the present invention. [Figure 5] 1A is a schematic diagram illustrating an example of a display device according to an embodiment of the present invention, and FIG. 1B is a schematic diagram illustrating an example of a foldable display device. [Figure 6] 1A is a schematic diagram showing an example of an illumination device according to an embodiment of the present invention, and FIG. 1B is a schematic diagram showing an example of an automobile having a vehicle lamp according to an embodiment of the present invention. [Figure 7] 1A is a schematic diagram showing an example of a wearable device according to an embodiment of the present invention, and FIG. 1B is a schematic diagram showing another example of a wearable device according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] ≪Organic compounds≫ First, the organic compound according to this embodiment will be described. The organic compound according to this embodiment is represented by the following general formula [1] or [2].

[0012]

Chemical formula

[0013] <X1 to X 18 、X 21 to X 38 > X1 to X 18 、X 21 to X 38 are each independently selected from a hydrogen 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 aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a silyl group, and a cyano group.

[0014] Examples of the halogen atom include, but are not limited to, fluorine, chlorine, bromine, iodine, etc.

[0015] Examples of the alkyl group include, but are not limited to, methyl group, ethyl group, normal propyl group, isopropyl group, normal butyl group, tertiary butyl group, secondary butyl group, octyl group, cyclohexyl group, 1 - adamantyl group, 2 - adamantyl group, etc. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms.

[0016] Examples of the alkoxy group include, but are not limited to, methoxy group, ethoxy group, propoxy group, 2 - ethyl - octyloxy group, benzyloxy group, etc. The alkoxy group is preferably an alkoxy group having 1 to 10 carbon atoms.

[0017] Examples of the amino group include, but are not limited to, an N-methylamino group, an N-ethylamino group, an N,N-dimethylamino group, an N,N-diethylamino group, an N-methyl-N-ethylamino group, an N-benzylamino group, an N-methyl-N-benzylamino group, an N,N-dibenzylamino group, an anilino group, an N,N-diphenylamino group, an N,N-dinaphthylamino group, an N,N-difluorenylamino group, an N-phenyl-N-tolylamino group, an N,N-ditolylamino group, an N-methyl-N-phenylamino group, an N,N-dianisolylamino group, an N-mesityl-N-phenylamino group, an N,N-dimesitylamino group, an N-phenyl-N-(4-tert-butylphenyl)amino group, an N-phenyl-N-(4-trifluoromethylphenyl)amino group, an N-piperidyl group, a carbazolyl group, and an acridyl group.

[0018] Examples of aryl groups include, but are not limited to, phenyl, naphthyl, indenyl, biphenyl, terphenyl, fluorenyl, phenanthryl, triphenylenyl, pyrenyl, anthranyl, perylenyl, chrysenyl, and fluoranthenyl groups. Preferred aryl groups are aromatic hydrocarbon groups having 6 to 60 carbon atoms.

[0019] Examples of heterocyclic groups include, but are not limited to, pyridyl, pyrimidyl, pyrazyl, triazyl, benzofuranyl, benzothiophenyl, dibenzofuranyl, dibenzothiophenyl, oxazolyl, oxadiazolyl, thiazolyl, thiadiazolyl, carbazolyl, acridinyl, and phenanthrolyl groups. Preferred heterocyclic groups are those having 3 to 60 carbon atoms.

[0020] Examples of the aryloxy group include, but are not limited to, a phenoxy group and a naphthoxy group.

[0021] Examples of heteroaryloxy groups include, but are not limited to, furanyloxy groups and thienyloxy groups.

[0022] Examples of the silyl group include, but are not limited to, a trimethylsilyl group and a triphenylsilyl group.

[0023] Examples of the substituent that the alkyl group, alkoxy group, amino group, aryl group, heterocyclic group, aryloxy group, and heteroaryloxy group may further have include alkyl groups such as a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, and a tertiary butyl group; aralkyl groups such as a benzyl group; aryl groups such as a phenyl group and a biphenyl group; heterocyclic groups such as a pyridyl group and a pyrrolyl group; amino groups such as a dimethylamino group, a diethylamino group, a dibenzylamino group, a diphenylamino group, and a ditolylamino group; alkoxy groups such as a methoxy group, an ethoxy group, and a propoxy group; aryloxy groups such as a phenoxy group; halogen atoms such as fluorine, chlorine, bromine, and iodine; and a cyano group, but are not limited to these.

[0024] <y> Y represents oxygen, sulfur, selenium, tellurium, a CRR group, or a carbonyl group.

[0025] R1 and R2 are each independently selected from a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkoxy group, a substituted or unsubstituted amino group, a substituted or unsubstituted aryl group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted heteroaryloxy group, a silyl group, and a cyano group.

[0026] Specific examples of the alkyl group, alkoxy group, amino group, aryl group, heterocyclic group, aryloxy group, heteroaryloxy group, and silyl group represented by R1 and R2 include X1 and X2. 18 , X 21 ~X 38 Examples of the substituents that may be further introduced by the alkyl group, alkoxy group, and heteroaryl group include, but are not limited to, those described above. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms. The alkoxy group is preferably an alkoxy group having 1 to 10 carbon atoms. The aryl group is preferably an aryl group having 6 to 60 carbon atoms. The heterocyclic group is preferably a heterocyclic group having 3 to 60 carbon atoms. Specific examples of the substituents that may be further introduced by the alkyl group, alkoxy group, amino group, aryl group, heterocyclic group, aryloxy group, and heteroaryloxy group include X1 to X2. 18 , X 21 ~X 38 Examples of the above-described examples include, but are not limited to, those described above.

[0027] <z> Z represents any one of a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a substituted or unsubstituted heterocyclic group, and is preferably a substituted or unsubstituted aryl group.

[0028] Specific examples of the alkyl group, aryl group, and heterocyclic group represented by Z include X1 to X 18 , X 21 ~X 38 Examples of the substituents that may be further introduced by the alkyl group, aryl group, and heterocyclic group include, but are not limited to, those described above. The alkyl group is preferably an alkyl group having 1 to 10 carbon atoms. The aryl group is preferably an aryl group having 6 to 60 carbon atoms. The heterocyclic group is preferably a heterocyclic group having 3 to 60 carbon atoms. Specific examples of the substituents that may be further introduced by the alkyl group, aryl group, and heterocyclic group include X1 to X2. 18 , X 21 ~X 38 Examples of the above-described examples include, but are not limited to, those described above.

[0029] Next, a method for synthesizing the organic compound according to this embodiment will be described. The organic compound according to this embodiment can be synthesized, for example, according to the reaction scheme shown below.

[0030] [ka]

[0031] Here, by appropriately changing the above-mentioned substituent X and appropriately changing Y from oxygen, sulfur, selenium, tellurium, a CRR group, or a carbonyl group, compounds represented by general formulas [1] and [2] can be obtained. However, the synthesis method is not limited to these.

[0032] Next, the organic compound according to this embodiment has the following characteristics, and therefore, when used in an organic light-emitting device, it provides an organic light-emitting device with high light emission efficiency and excellent driving durability. The basic skeleton in this embodiment is the X1 to X2 of the compound represented by general formula [1] or [2]. 18 , X 21 ~X 38 are all hydrogen atoms, Z is an unsubstituted phenyl group, and Y is a CR1R2 group, the skeleton further has R1 to R2 all being hydrogen atoms. (1) The ST gap is small because one of the rings in the spiro structure has an electron-withdrawing carbonyl group on the fluorene ring side and the other ring has an electron-donating acridine ring. (2) By using Y as an electron-donating group, the band gap of the molecule is widened, and the band gap is more suitable for the light-emitting layer. (3) The spiro structure makes molecular association less likely to occur. (4) The spiro structure makes the bond at the quaternary carbon less likely to be cleaved.

[0033] The features will be explained below. (1) The ST gap is small because one of the rings in the spiro structure has an electron-withdrawing carbonyl group on the fluorene ring side and the other ring has an electron-donating acridine ring.

[0034] In the compounds of this embodiment, as shown in Table 1, B-1 to B-3, the portion occupying the LUMO electron orbital distribution and the portion occupying the HOMO electron orbital distribution are separated via the spiro moiety of the spiro structure. In other words, it can be seen that there are few portions occupying both the HOMO and LUMO. This leads to a small overlap integral and a small difference between the excited singlet state (S1) and the excited triplet state (T1).

[0035] The above characteristics are due to the presence of an electron-withdrawing carbonyl group on the fluorene ring, which is one of the rings in the spiro structure, and an electron-donating acridine ring on the other ring. On the other hand, b-1 and b-2 only have either an electron-withdrawing carbonyl group or an electron-donating acridine ring, so the LUMO electron orbital distribution and the HOMO electron orbital distribution are not separated. Furthermore, b-3 does not have an electron-withdrawing carbonyl group or an electron-donating acridine ring via the spiro structure. Therefore, the LUMO electron orbital distribution and the HOMO electron orbital distribution overlap and are not separated in the phenylene group connecting the triazine ring and the acridine ring. This results in a large overlap integral, and a large difference between the excited singlet state (S1) and the excited triplet state (T1). Note that B-1 to B-3 correspond to Exemplary Compounds C-1, D-1, and C-13, respectively, which will be described later. Furthermore, b-3 is compound A-2 of Patent Document 2 (comparative compound J-2 described later).

[0036] [Table 1]

[0037] The above calculation results were visualized using molecular orbital calculations. The calculation method used for molecular orbital calculations was the density functional theory (DFT), which is currently widely used. The functional used was B3LYP, and the basis set was 6-31G. * It is also a smooth-flowing waveguide called Gaussian09(Gaussian09, RevisionC.01,MJFrisch,GWTrucks,HBSchlegel,GEScuse ria, MARobb,JRCheeseman,G.Scalmani,V.Barone,B.Mennucci,GAPetersson,H.Nakatsuji,M.Caricato,X.Li,HPHra tchian, AFIzmaylov, J. Bloino, G. Zheng, JLSonnenberg, M. Hada, M. Ehara, K. Toyota, R. Fukuda, J. Hasegawa, M. Ishi da,T.Nakajima,Y.Honda,O.Kitao,H.Nakai,T.Vreven,JAMontgomery,Jr.,JEPeralta,F.Ogliaro,M.Bearpark,JJHe yd, E. Brothers, KNKudin, VNS Taroverov, T. Keith, R. Kobayashi, J. Normand, K. Raghavachari, A. Rendell, JCBurant ,SSIyengar,J.Tomasi,M.Cossi,N.Rega,JMMillam,M.Klene,JEKnox,JBCross,V.Bakken,C.Adamo,J.Jaramillo,R.G omperts,REStratmann,O.Yazyev,AJAustin,R.Cammi,C.Pomelli,JWOchterski,RLMartin,K.Morokuma,VGZakrzews ki,GAVoth,P.Salvador,JJDannenberg,S.Dapprich,ADDaniels,O.Farkas,JBForesman,JVOrtiz,JCioslowski,and DJFox,Gaussian,Inc.,Wallingford CT,2010.)

[0038] As described above, the compounds B-1 to B-3 of this embodiment are characterized by a small difference between S1 and T1. As a result, when the compounds of this embodiment are used in the light-emitting layer of an organic light-emitting device, the device provides highly efficient light emission. This is because the difference between S1 and T1 is small. For excitons generated in a 1:3 ratio of singlet excitons and triplet excitons, the compound can be used for delayed fluorescence emission, in which triplet excitons that have normally been thermally deactivated emit light from the singlet excited state. A small difference between S1 and T1 is advantageous for converting triplet excitons to the singlet excited state, as this reduces the energy barrier. The compounds of this embodiment are advantageous for these conditions, providing devices with highly efficient light emission.

[0039] On the other hand, the comparative compounds b-1 and b-2 have only one of an electron-withdrawing carbonyl group or an electron-donating acridine ring, and b-3 does not have an electron-withdrawing carbonyl group or an electron-donating acridine ring via a spiro structure. Therefore, the difference between S1 and T1 is large, resulting in a large energy barrier, making it disadvantageous for delayed fluorescence emission.

[0040] (2) By using Y as an electron-donating group, the band gap of the molecule is widened, and the band gap is more suitable for the light-emitting layer.

[0041] When Y is oxygen, sulfur, selenium, tellurium, or a CRR group, it has electron-donating properties, and therefore the S1 value is 424 nm to 467 nm, as shown in Table 1, which is a value suitable for blue and green emission in the visible region. On the other hand, when Y is a carbonyl group, it has electron-withdrawing properties, and therefore the S1 value is 550 nm or more, which is a value suitable for a red-emitting layer.

[0042] (3) The spiro structure makes molecular association less likely to occur.

[0043] The compound of this embodiment has a spiro structure, which makes it difficult for molecular association to occur. The two rings are nearly perpendicular to each other via the spiro structure, resulting in low molecular planarity. Therefore, stacking of molecules is unlikely to occur, making molecular association unlikely. On the other hand, in the case of a compound without a spiro structure, such as b-1 in Table 1, the two phenyl groups bonded to the fluorene ring can freely rotate, resulting in high planarity. Therefore, molecular association is likely to occur.

[0044] The above effect is that when the compound of this embodiment is used in the organic layer of an organic light-emitting element, a stable amorphous film is formed that is resistant to crystallization, and an organic light-emitting element that is highly durable and does not crystallize even when driven for a long period of time is obtained.

[0045] Furthermore, when the compound of this embodiment is used in the light-emitting layer of an organic light-emitting device, molecular association is unlikely to occur, and therefore concentration quenching is unlikely to occur, resulting in an organic light-emitting device with high light-emitting efficiency.

[0046] The above effect also improves sublimation properties. Improved sublimation properties enable the high purity of materials through sublimation purification and the fabrication of organic light-emitting devices through vapor deposition. This reduces impurities contained in organic light-emitting devices, preventing impurities from causing a decrease in luminous efficiency and driving durability.

[0047] (4) The spiro structure makes the bond at the quaternary carbon less likely to be cleaved.

[0048] In the compound of this embodiment, the quaternary carbon at the dotted line in the chemical formula below has a spiro structure, and even if cleaved, the cleaved phenyl group remains bonded to the main structure, making it easy to return to the original structure. In the case of a non-spiro structure such as compound A-1 in Patent Document 1, upon cleavage, the cleaved phenyl group is not bonded to the main structure, making it difficult to return to the original structure. Therefore, the device durability deteriorates because the cleavage is easy and the structure is easily changed.

[0049] [ka]

[0050] Furthermore, the compounds of the present embodiment have the following emission wavelength characteristics. That is, among the compounds of the present embodiment, the compound represented by general formula [1] emits light at a longer wavelength than the compound represented by general formula [2]. As shown in Table 1, B-1, which is a compound represented by general formula [1], has an S1 of 467 nm and emits green light, and B-3, which is a compound represented by general formula [2], has an S1 of 424 nm and emits blue light.

[0051] Furthermore, the compound of this embodiment is preferably used in the light-emitting layer of an organic light-emitting device, and in that case, it has the following characteristics. (5) By mixing the compound of this embodiment with a host material in the light-emitting layer, the compound of this embodiment is more likely to cause exciton recombination, providing a highly efficient light-emitting device. (6) By mixing the compound of this embodiment with a host material in the light-emitting layer and further including a light-emitting material, a light-emitting device with high efficiency and high color purity can be provided. (7) When the light-emitting material is a hydrocarbon compound, a light-emitting device with high efficiency and excellent durability can be provided.

[0052] The features will be explained below. (5) By mixing the compound of this embodiment with a host material in the light-emitting layer, the compound of this embodiment is more likely to cause exciton recombination, providing a highly efficient light-emitting device.

[0053] The compound of this embodiment has an electron-withdrawing carbonyl group and an electron-donating acridine ring. Therefore, when mixed with a host material in the light-emitting layer of an organic light-emitting device, the LUMO of the compound of this embodiment is lower than that of the host material (farther from the vacuum level), and the HOMO of the compound of this embodiment is higher than that of the host material (closer to the vacuum level). Therefore, electrons and holes supplied from the transport layer in the light-emitting layer are trapped by the compound of this embodiment, resulting in exciton recombination. As described in Feature (1) above, the compound of this embodiment has a small difference between S1 and T1, which allows efficient delayed fluorescence emission in the light-emitting layer and allows more triplet excitons to be utilized for light emission. This effect is particularly pronounced when the host material is a hydrocarbon compound, as the energy difference between the HOMO and LUMO of the host and the compound of this embodiment is greater, making it easier to trap electrons and holes. A hydrocarbon compound is a compound composed solely of carbon and hydrogen.

[0054] Furthermore, as described in the above feature (3), the compound of this embodiment is less likely to undergo molecular association, and therefore is less likely to undergo concentration quenching in a host material. This effect leads to preventing quenching due to interactions between excitons when the compound of this embodiment is in an excited state, and is effective in efficiently generating delayed fluorescence emission in the light-emitting layer.

[0055] (6) By mixing the compound of this embodiment with a host material in the light-emitting layer and further including a light-emitting material, a light-emitting device with high efficiency and high color purity can be provided.

[0056] By using the compound of this embodiment in the light-emitting layer and further doping it with a light-emitting material having a high luminescence quantum yield or a light-emitting material having an emission spectrum suitable for exhibiting high color purity, a light-emitting device with even higher efficiency and color purity can be provided. In this case, the compound of this embodiment must be present in the light-emitting layer at a concentration sufficient to preferentially trap electrons and holes in order to facilitate exciton recombination. The concentration of the organic compound of this embodiment is preferably 0.1% by mass or more and 45% by mass or less, and more preferably 1% by mass or more and 30% by mass or less, of the entire light-emitting layer.

[0057] On the other hand, a lower doping concentration of the luminescent material is preferable because it is less susceptible to concentration quenching and changes in the emission spectrum due to interactions between molecules, and therefore it is preferable to dope a luminescent material other than the compound of this embodiment into the luminescent layer. The concentration of the luminescent material is preferably 0.01% by mass or more and 20% by mass or less, and more preferably 1% by mass or more and 15% by mass or less, based on the entire luminescent layer. As a result, a light-emitting device with high efficiency and high color purity can be provided.

[0058] (7) When the light-emitting material is a hydrocarbon compound, a light-emitting device with high efficiency and excellent durability can be provided.

[0059] Since the compound of this embodiment has a carbonyl group with strong electron-withdrawing properties, the doped light-emitting material described in the above feature (6) is preferably a light-emitting material that does not have an amino group, which is an electron-donating group, and is preferably a hydrocarbon compound. The reason is that a light-emitting material having an amino group may interact with the carbonyl group of the compound of this embodiment in the light-emitting layer, resulting in a decrease in light-emitting efficiency due to exciplex formation and a change in the light-emitting spectrum of the light-emitting material, which may deteriorate the color purity of the light-emitting element.

[0060] Furthermore, light-emitting materials with amino groups have a low ionization potential, making them susceptible to oxidation and resulting in poor device durability. Therefore, hydrocarbon compounds are preferred as light-emitting materials, and fused polycyclic compounds with five-membered rings are even more preferred. This is because their higher ionization potential makes them less susceptible to oxidation. Hydrocarbon compounds are compounds composed only of carbon and hydrogen.

[0061] As described above, by mixing the compound of this embodiment with a host material in the light-emitting layer, an organic light-emitting device with high light emission efficiency can be obtained. In this case, the light-emitting material may be the compound of this embodiment, or an additional light-emitting material may be mixed and the compound of this embodiment may function as an assist material. By using a light-emitting material with good color purity, an organic light-emitting device with high efficiency and high color purity can be obtained. Furthermore, when the host material is a hydrocarbon compound, the compound of this embodiment tends to trap electrons and holes, which is preferable because it significantly improves efficiency.

[0062] Specific examples of the organic compound according to this embodiment are shown below. (C-12, 24, D-12, 24, E-12, F-11, 19, 23, 24, G-8 are examples) However, the present invention is not limited to these.

[0063] [ka]

[0064] [ka]

[0065] [ka]

[0066] [ka]

[0067] [ka]

[0068] [ka]

[0069] [ka]

[0070] [ka]

[0071] Group C includes compounds represented by general formula [1] or [2] in which Y is oxygen. When Y is oxygen, chemical reactions such as oxidation are unlikely to occur, and chemically stable compounds are provided.

[0072] Group D compounds are those represented by the general formula [1] or [2] where Y is sulfur. Because Y is sulfur, the radius of the element is larger than that of oxygen, so the six-membered ring that is formed becomes distorted, destroying the planarity of the molecule. This makes them less susceptible to concentration quenching.

[0073] Group E includes compounds represented by the general formula [1] or [2] where Y is selenium or tellurium. When Y is selenium or tellurium, it has a d orbital and is a metallic element, so electron mobility is high.

[0074] Group F compounds are those represented by general formula [1] or [2] in which Y is a CR1R2 group. The introduction of R1 and R2, especially the introduction of groups other than hydrogen into R1 and R2, disrupts the planarity of the molecule. This makes them less susceptible to concentration quenching.

[0075] Group G is a compound represented by the general formula [1] or [2] in which Y is a carbonyl group. The increased electron-withdrawing ability provides a stable compound that is less susceptible to oxidation.

[0076] <Organic light-emitting element> Next, the organic light-emitting device of this embodiment will be described.

[0077] The organic light-emitting element of this embodiment has at least a pair of electrodes, an anode and a cathode, and an organic compound layer disposed between these electrodes. In the organic light-emitting element of this embodiment, the organic compound layer may be a single layer or a laminate consisting of multiple layers, as long as it has a light-emitting layer. When the organic compound layer is a laminate consisting of multiple layers, the organic compound layer may have, in addition to the light-emitting layer, a hole injection layer, a hole transport layer, an electron blocking layer, a hole / exciton blocking layer, an electron transport layer, an electron injection layer, etc. Furthermore, the light-emitting layer may be a single layer or a laminate consisting of multiple layers.

[0078] In the organic light-emitting device of this embodiment, the organic compound according to this embodiment is contained in at least one of the organic compound layers. Specifically, the organic compound according to this embodiment is contained in any of the above-mentioned light-emitting layer, hole injection layer, hole transport layer, electron blocking layer, light-emitting layer, hole / exciton blocking layer, electron transport layer, electron injection layer, etc. The organic compound according to this embodiment is preferably contained in the light-emitting layer. The light-emitting layer can emit green or red light, but the emitted color is not limited thereto.

[0079] In the organic light-emitting device of this embodiment, when the organic compound according to this embodiment is contained in the light-emitting layer, the light-emitting layer may be a layer consisting solely of the organic compound according to this embodiment, or may be a layer consisting of the organic compound according to this embodiment and other compounds. Here, when the light-emitting layer is a layer consisting of the organic compound according to this embodiment and other compounds, the organic compound according to this embodiment may be used as a host or a guest of the light-emitting layer. It may also be used as an assist material that can be contained in the light-emitting layer. Here, the host is the compound with the largest mass ratio among the compounds constituting the light-emitting layer. Furthermore, the guest is a compound with a mass ratio smaller than that of the host among the compounds constituting the light-emitting layer, and is a compound that is mainly responsible for light emission. Furthermore, the assist material is a compound with a mass ratio smaller than that of the host among the compounds constituting the light-emitting layer, and assists the light emission of the guest.

[0080] When the organic compound according to this embodiment is used as a guest in the light-emitting layer, the concentration of the guest is preferably 0.01% by mass to 20% by mass, and more preferably 1% by mass to 15% by mass, based on the total mass of the light-emitting layer. When the organic compound according to this embodiment is used as an assist material in the light-emitting layer, the concentration of the assist material is preferably 0.1% by mass to 45% by mass, and more preferably 1% by mass to 30% by mass, based on the total mass of the light-emitting layer.

[0081] Furthermore, when the organic compound according to this embodiment is used as a guest in the light-emitting layer, it is preferable to use a material having a higher LUMO than the organic compound according to this embodiment (a material having a LUMO closer to the vacuum level) as the host. This is because the organic compound according to this embodiment tends to have a low LUMO, and by using a material having a higher LUMO than the organic compound according to this embodiment as the host, the organic compound according to this embodiment can receive more electrons supplied to the host in the light-emitting layer.

[0082] Furthermore, when the organic compound according to this embodiment is used as an assist material in the light-emitting layer, it is preferable to use a material with a higher LUMO than the organic compound according to this embodiment (a material with a LUMO closer to the vacuum level) as a guest. This is because the organic compounds according to this embodiment tend to have a low LUMO. Therefore, by using a material with a higher LUMO than the organic compound according to this embodiment as the light-emitting material (guest), the organic compound according to this embodiment can receive more electrons supplied to the host in the light-emitting layer, and the assist material can be responsible for exciton recombination. As a result, energy can be efficiently transferred to the light-emitting material (guest).

[0083] The present inventors have conducted various studies and found that when the organic compound according to this embodiment is used as a host, guest, or assist material in the light-emitting layer, particularly as a guest in the light-emitting layer, a device exhibiting high-efficiency, high-brightness light output and extremely high durability can be obtained. Furthermore, when the organic compound is used as an assist material in the light-emitting layer, a device exhibiting high-efficiency, high-brightness light output and extremely high durability can be obtained. The light-emitting layer may be a single layer or multiple layers, and may contain multiple light-emitting materials. A multiple layer may mean a stack of a light-emitting layer and another light-emitting layer, or a stack of multiple light-emitting layers with an intermediate layer stacked between them. Tandem or stacked elements are also possible. In these cases, the emitted color of the organic light-emitting device is not limited to a single color. More specifically, it may be white or a neutral color. Furthermore, the film formation method is performed by vapor deposition or coating. Details of this will be explained in detail in the examples below.

[0084] The organic compound according to this embodiment can be used as a constituent material of an organic compound layer other than the light-emitting layer that constitutes the organic light-emitting device of this embodiment, specifically, as a constituent material of an electron transport layer, an electron injection layer, a hole transport layer, a hole injection layer, a hole blocking layer, etc.

[0085] In addition to the organic compound 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 together as needed. Examples of these compounds are listed below.

[0086] As the hole injection and transport material, a material with high hole mobility is preferred so that holes can be easily injected from the anode and the injected holes can be transported to the light-emitting layer. Furthermore, a material with a high glass transition temperature is preferred to reduce deterioration of film quality, such as crystallization, in organic light-emitting devices. 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. Specific examples of compounds that can be used as hole injection and transport materials are listed below, but the present invention is not limited to these.

[0087] [ka]

[0088] Among the hole transport materials listed above, HT16 to HT18 can reduce the driving voltage when used in a layer in contact with the anode. HT16 is widely used in organic light-emitting devices. HT2, HT3, HT4, HT5, HT6, HT10, and HT12 may be used in an organic compound layer adjacent to HT16. Furthermore, multiple materials may be used in one organic compound layer.

[0089] Examples of light-emitting materials that are primarily involved in light-emitting function include organic compounds represented by general formulas [1] and [2], as well as 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 listed below, but of course, they are not limited to these.

[0090] [ka]

[0091] [ka]

[0092] The light-emitting material is preferably a hydrocarbon compound, as this prevents a decrease in luminous efficiency due to exciplex formation and a deterioration in color purity due to changes in the light-emitting spectrum of the light-emitting material. Hydrocarbon compounds are compounds composed only of carbon and hydrogen, and examples of these include BD7, BD8, GD5 to GD9, and RD1. The light-emitting material is more preferably a fused polycyclic ring containing a five-membered ring, as this has a high ionization potential, making it less susceptible to oxidation and providing a device with a long, durable lifespan. Examples of these include BD7, BD8, GD5 to GD9, and RD1.

[0093] Examples of the light-emitting layer host or light-emitting assist material contained in the light-emitting layer include aromatic hydrocarbon compounds or derivatives thereof, as well as carbazole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, organoaluminum complexes such as tris(8-quinolinolato)aluminum, and organic beryllium complexes. Specific examples of compounds used as the light-emitting layer host or light-emitting assist material contained in the light-emitting layer are shown below, but the present invention is not limited to these.

[0094] [ka]

[0095] When the host material is a hydrocarbon compound, the compound of this embodiment is more likely to trap electrons and holes, which is preferable because it significantly improves efficiency. Hydrocarbon compounds are compounds composed only of carbon and hydrogen, and examples of these compounds include EM1 to EM12 and EM16 to EM27.

[0096] 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, 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 of course, the present invention is not limited to these.

[0097] [ka]

[0098] The electron injection material can be selected from those that allow easy electron injection from the cathode, taking into consideration the balance with hole injection properties, etc. 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, benzimidazolidene derivatives, imidazolidene derivatives, fulvalene derivatives, and acridine derivatives.

[0099] <Configuration of organic light-emitting element> The organic light-emitting element is provided by forming an anode, an organic compound layer, and a cathode on a substrate. A protective layer, a color filter, etc. may be provided on the cathode. 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 acrylic resin or the like.

[0100] [substrate] Examples of the substrate include quartz, glass, silicon wafer, resin, and metal. Furthermore, the substrate may be provided with a switching element such as a transistor and wiring, and an insulating layer thereon. The insulating layer may be made of any material as long as it can form a contact hole to ensure electrical continuity between the anode and the wiring and can ensure insulation from unconnected wiring. For example, resins such as polyimide, silicon oxide, silicon nitride, etc. can be used.

[0101] [electrode] A pair of electrodes can be used. The pair of electrodes may be an anode and a cathode. 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.

[0102] The anode material should have as high a work function as possible. Examples 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.

[0103] 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.

[0104] When used as a reflective electrode, for example, chromium, aluminum, silver, titanium, tungsten, molybdenum, or alloys or laminates thereof can be used. 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 techniques can be used to form the electrodes.

[0105] 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, a 1:1 ratio is acceptable.

[0106] 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 preferred because they provide good film coverage and make it easier to reduce resistance.

[0107] [Protective layer] A protective layer may be provided on the cathode. For example, by adhering glass provided with a moisture absorbent on the cathode, it is possible to prevent water and other substances from penetrating the organic compound layer, thereby suppressing display defects. In another embodiment, a passivation film such as silicon nitride may be provided on the cathode to prevent water and other substances from penetrating the organic compound layer. For example, after forming the cathode, the device may be transported to another chamber without breaking the vacuum, and a silicon nitride film with a thickness of 2 μm may be formed by CVD to serve as a protective layer. A protective layer may also be provided using atomic layer deposition (ALD) after film formation by CVD.

[0108] [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.

[0109] [Planarization layer] A planarizing layer may be provided between the color filter and the protective layer. The planarizing layer may be made of an organic compound, and may be either a low molecular weight or a high molecular weight, but is preferably a high molecular weight.

[0110] 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.

[0111] [Counter substrate] A 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 counter substrate may be made of the same material as the aforementioned substrate.

[0112] [Organic layer] The organic compound layers (hole injection layer, hole transport layer, electron blocking layer, light emitting layer, hole blocking layer, electron transport layer, electron injection layer, etc.) constituting the organic light emitting device according to one embodiment of the present invention are formed by the method shown below.

[0113] The organic compound layer constituting the organic light-emitting device according to one embodiment of the present invention can be formed by dry processes such as vacuum deposition, ionization deposition, sputtering, plasma, etc. Alternatively to the dry process, a wet process can be used in which the compound is dissolved in an appropriate solvent and a layer is formed by a known coating method (for example, spin coating, dipping, casting, LB method, inkjet method, etc.).

[0114] 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.

[0115] Examples of the binder resin include, but are not limited to, polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenol resin, epoxy resin, silicone resin, and urea resin.

[0116] 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.

[0117] <Uses of the organic light-emitting device according to this embodiment> The organic light-emitting device according to this embodiment can be used as a component of a display device or a lighting device, and can also be used as an exposure light source for an electrophotographic image forming device, a backlight for a liquid crystal display device, or a light-emitting device having a white light source and a color filter.

[0118] 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 may have the organic light-emitting element of this embodiment and a transistor connected to the organic light-emitting element.

[0119] 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.

[0120] Next, a display device according to this embodiment will be described with reference to the drawings. Fig. 1 is a cross-sectional view showing an example of a display device having an organic light-emitting element and a transistor connected to the organic light-emitting element. The transistor is an example of an active element. The transistor may be a thin-film transistor (TFT).

[0121] FIG. 1(a) shows an example of a pixel, which is a component of the display device according to this embodiment. The pixel includes sub-pixels 10. The sub-pixels are divided into 10R, 10G, and 10B based on the light emitted from the sub-pixels. The emitted colors may be distinguished by the wavelength of light emitted from the light-emitting layer, or the light emitted from the sub-pixels may be selectively transmitted or color-converted using a color filter or the like. Each sub-pixel 10 includes a reflective electrode serving as a first electrode 2 on an interlayer insulating layer 1, an insulating layer 3 covering the edges of the first electrode 2, an organic compound layer 4 covering the first electrode 2 and the insulating layer 3, a transparent electrode serving as a second electrode 5, a protective layer 6, and a color filter 7.

[0122] A transistor and a capacitor element may be disposed below or inside the interlayer insulating layer 1. The transistor and the first electrode 2 may be electrically connected via a contact hole or the like (not shown). The insulating layer 3 is also called a bank or a pixel separation film. It covers the edges of the first electrode 2 and is disposed to surround the first electrode 2. The portion where the insulating layer 3 is not disposed is in contact with the organic compound layer 4 and becomes a light-emitting region.

[0123] The organic compound layer 4 includes a hole injection layer 41 , a hole transport layer 42 , a first light-emitting layer 43 , a second light-emitting layer 44 , and an electron transport layer 45 . The second electrode 5 may be a transparent electrode, a reflective electrode, or a semi-transparent electrode. The protective layer 6 reduces the penetration of moisture into the organic compound layer 4. Although the protective layer 6 is illustrated as being one layer, it may be multiple layers, and each layer may be an inorganic compound layer and an organic compound layer.

[0124] The color filters 7 are divided into 7R, 7G, and 7B depending on their colors. The color filters 7 may be formed on a planarization film (not shown). A resin protective layer (not shown) may be provided on the color filters 7. The color filters 7 may be formed on a protective layer 6. Alternatively, the color filters 7 may be provided on an opposing substrate such as a glass substrate and then bonded thereto.

[0125] The display device 100 in FIG. 1(b) has an organic light-emitting element 26 and a TFT 18 as an example of a transistor. A substrate 11 made of glass, silicon, or the like is provided with an insulating layer 12 on top of it. An active element such as the TFT 18 is disposed on the insulating layer 12, and a gate electrode 13, a gate insulating film 14, and a semiconductor layer 15 of the active element are disposed on top of it. The TFT 18 also comprises a drain electrode 16 and a source electrode 17. An insulating film 19 is provided on top of the TFT 18. An anode 21 constituting the organic light-emitting element 26 and the source electrode 17 are connected via a contact hole 20 provided in the insulating film 19.

[0126] The electrical connection method between the electrodes (anode 21, cathode 23) included in the organic light-emitting element 26 and the electrodes (source electrode 17, drain electrode 16) included in the TFT 18 is not limited to the embodiment shown in Fig. 1(b). In other words, it is sufficient that either the anode 21 or the cathode 23 is electrically connected to either the source electrode 17 or the drain electrode 16 of the TFT 18. TFT stands for thin film transistor.

[0127] 1(b), the organic compound layer 22 is illustrated as a single layer, but may be a multi-layer organic compound layer 22. A first protective layer 24 and a second protective layer 25 are provided on the cathode 23 to reduce deterioration of the organic light-emitting element 26.

[0128] Although the display device 100 in FIG. 1(b) uses transistors as switching elements, other switching elements may be used instead.

[0129] The transistors used in the display device 100 of Fig. 1(b) are not limited to transistors using single-crystal silicon wafers, but may also be thin-film transistors having an active layer on an insulating surface of a substrate. Examples of active layers include single-crystal silicon, amorphous silicon, microcrystalline silicon, and other non-single-crystal silicon, as well as non-single-crystal oxide semiconductors such as indium zinc oxide and indium gallium zinc oxide. Thin-film transistors are also called TFT elements.

[0130] The transistors included in the display device 100 of Fig. 1(b) may be formed within a substrate such as a Si substrate. Here, "formed within a substrate" means that the substrate itself, such as a Si substrate, is processed to form the transistors. In other words, having a transistor within a substrate can be seen as the substrate and the transistor being integrally formed.

[0131] The organic light-emitting element according to this embodiment has its emission brightness controlled by a TFT, which is an example of a switching element. By providing multiple organic light-emitting elements on a surface, an image can be displayed based on the emission brightness of each element. Note that the switching element according to this embodiment is not limited to a TFT, and may be a transistor formed from low-temperature polysilicon or an active matrix driver formed on a substrate such as a Si substrate. "On the substrate" can also be referred to as "inside the substrate." Whether to provide a transistor in the substrate or to 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 the organic light-emitting element on a Si substrate.

[0132] FIG. 2(a) is a schematic diagram showing an example of an image forming apparatus according to one embodiment of the present invention. The image forming apparatus 40 is an electrophotographic image forming apparatus and includes a photoconductor 27, an exposure light source 28, a charging unit 30, a developing unit 31, a transfer unit 32, a transport roller 33, and a fixing unit 35. Light 29 is irradiated from the exposure light source 28, and an electrostatic latent image is formed on the surface of the photoconductor 27. The exposure light source 28 includes an organic light-emitting element according to this embodiment. The developing unit 31 includes toner and the like. The charging unit 30 charges the photoconductor 27. The transfer unit 32 transfers the developed image to a recording medium 34. The transport roller 33 transports the recording medium 34. The recording medium 34 is, for example, paper. The fixing unit 35 fixes the image formed on the recording medium 34.

[0133] 2(b) and 2(c) are diagrams showing the exposure light source 28 and are schematic diagrams illustrating multiple light-emitting units 36 arranged on a long substrate. Arrow 37 indicates the direction parallel to the axis of the photoconductor, which 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 27 rotates. This direction can also be referred to as the long axis direction of the photoconductor 27. FIG. 2(b) shows a configuration in which the light-emitting units 36 are arranged along the long axis direction of the photoconductor 27. FIG. 2(c) shows a different configuration from FIG. 2(b), in which the light-emitting units 36 are arranged alternately in the column direction in 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 36 are arranged at intervals. In the second column, light-emitting units 36 are located at positions corresponding to the intervals between the light-emitting units 36 in the first column. In other words, multiple light-emitting units 36 are also arranged at intervals in the row direction. The arrangement in FIG. 2(c) can also be described as a grid-like arrangement, a houndstooth arrangement, or a checkerboard pattern.

[0134] 3 is a schematic diagram illustrating an example of a display device according to this embodiment. The display device 1000 may include 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.

[0135] The display device according to this embodiment may have color filters having red, green, and blue colors, which may be arranged in a delta arrangement.

[0136] The display device according to the present embodiment may be 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.

[0137] The display device according to this embodiment may be used as a display unit of an imaging device having an optical unit with a plurality of 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 disposed within a viewfinder. The imaging device may be a digital camera or a digital video camera.

[0138] 4A is a schematic diagram showing an example of an imaging device according to this embodiment. The imaging device 1100 may include a viewfinder 1101, a rear display 1102, an operation unit 1103, and a housing 1104. The viewfinder 1101 may include 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.

[0139] 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 of 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.

[0140] 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 can include an imaging method that detects the difference from the previous image, or a method of cutting out an image from a constantly recorded image, etc.

[0141] FIG. 4(b) 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 1202 may be a biometric recognition unit that recognizes a fingerprint to perform unlocking or the like. An electronic device having a communication unit can also be called a communication device. The electronic device 1200 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 1201. Examples of the electronic device 1200 include a smartphone and a laptop computer.

[0142] FIG. 5 is a schematic diagram illustrating an example of a display device according to this embodiment. FIG. 5(a) illustrates a display device such as a television monitor or a PC monitor. The display device 1300 has a frame 1301 and a display unit 1302. The display unit 1302 may use a light-emitting element according to this embodiment. The display device 1300 has 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. 5(a). 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.

[0143] FIG. 5(b) is a schematic diagram illustrating another example of a display device according to this embodiment. The display device 1310 in FIG. 5(b) is configured to be bendable, and is a so-called foldable display device. The display device 1310 has 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 may include light-emitting elements according to this embodiment. The first display unit 1311 and the second display unit 1312 may be a single, seamless display unit. 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.

[0144] FIG. 6(a) is a schematic diagram illustrating an example of a lighting device according to this embodiment. The lighting device 1400 may include a housing 1401, a light source 1402, a circuit board 1403, an optical filter 1404 that transmits light emitted by the light source 1402, and a light diffusion unit 1405. The light source 1402 may include 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, 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 emission side of the lighting. If necessary, a cover may be provided on the outermost surface.

[0145] 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 may have the organic light-emitting element of this embodiment and a power supply circuit connected thereto. The power supply circuit is a circuit that converts AC voltage to 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.

[0146] 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 a metal with a high specific heat capacity or liquid silicon.

[0147] 6(b) 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 lighting fixtures. The automobile 1500 has tail lamps 1501, and may be configured to turn on the tail lamps when braking or the like is performed.

[0148] The tail lamp 1501 may include an 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.

[0149] 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 an 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.

[0150] The moving body according to this embodiment may be a ship, an aircraft, a drone, or the like. The moving body may have a body and a lighting device provided on the body. The lighting device may emit light to indicate the position of the body. The lighting device has the organic light-emitting element according to this embodiment.

[0151] An application example of the display device of each of the above-described embodiments will be described with reference to Fig. 7. The display device can be applied to a system that can be attached as a wearable device, such as smart glasses, an HMD, or a smart contact lens. The image capturing and display device used in such an application example includes an image capturing device capable of photoelectrically converting visible light and a display device capable of emitting visible light.

[0152] Fig. 7(a) is a schematic diagram showing an example of a wearable device according to an embodiment of the present invention. Using Fig. 7(a), glasses 1600 (smart glasses) according to one application example will be described. An imaging device 1602 such as a CMOS sensor or SPAD is provided on the front side of a lens 1601 of the glasses 1600. In addition, a display device according to each of the above-mentioned embodiments is provided on the back side of the lens 1601.

[0153] 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. 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.

[0154] FIG. 7(b) is a schematic diagram showing another example of a wearable device according to an embodiment of the present invention. Using FIG. 7(b), glasses 1610 (smart glasses) according to one application example will be described. The glasses 1610 have a control device 1612, which is equipped with an imaging device corresponding to the imaging device 1602 in FIG. 7(a) and a display device. A lens 1611 is formed with an optical system for projecting light emitted from the imaging device in the control device 1612 and the display device, and an image is projected onto the lens 1611. The control device 1612 functions as a power source that supplies power to the imaging device and the display device, and also controls the operation of the imaging device and the display device.

[0155] The control device 1612 may include a gaze detection unit that detects the wearer's gaze. The gaze detection may use infrared light. The infrared light emitter emits infrared light toward the eyeball of the user gazing at the display image. An imaging unit with a light-receiving element detects the reflected infrared light from the eyeball, thereby obtaining a captured image of the eyeball. A reduction unit that reduces light from the infrared light emitter to the display unit in a planar view reduces degradation of image quality. The user's gaze toward the displayed image is detected from the captured image of the eyeball obtained by capturing infrared light. Any known method can be applied to gaze detection using the captured 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 based on the pupil-corneal reflex method is performed. Using the pupil-corneal reflex method, a gaze vector representing the orientation (rotation angle) of the eyeball is calculated based on the image of the pupil and the Purkinje image included in the captured image of the eyeball, thereby detecting the user's gaze.

[0156] A display device according to one embodiment of the present invention 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.

[0157] The display area includes a first display area and a second display area different from the first display area, and a high-priority area is determined from the first display area and the second display area based on 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. 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.

[0158] 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 an 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 an external device, it is transmitted to the display device via communication.

[0159] 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.

[0160] 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. [Example]

[0161] The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0162] [Example 1 (Synthesis of Exemplary Compound C-1)] Exemplary compound C-1 was synthesized according to the following scheme.

[0163] [ka]

[0164] (1) Synthesis of compound m-3 The following reagents and solvents were placed in a 200 ml recovery flask. Compound m-1: 3.9g (20.0mmol) Compound m-2: 3.1g (20.0mmol) Sodium tert-butyloxide: 5.8g (60.0mmol) Pd(dba)2: 575mg Tri-tert-butylphosphine: 606 mg Orthoxylene: 60ml The reaction solution was then heated and stirred at 140°C for 5 hours under a nitrogen stream. After the reaction was completed, the mixture was filtered through Celite and concentrated to dryness. The resulting solid was purified by silica gel column chromatography (toluene:ethyl acetate mixture) to obtain 4.1 g (yield: 76%) of a yellowish white solid m-3.

[0165] (2) Synthesis of compound m-6 The following reagents and solvents were placed in a 200 ml recovery flask. Compound m-4: 3.2g (10.0mmol) Compound m-5: 2.2g (11.0mmol) Sodium carbonate: 5.3 g (50.0 mmol) Pd(PPh3)4: 578 mg Toluene: 35 ml Water: 35ml Ethanol: 10ml The reaction solution was then heated and stirred at 60°C for 5 hours under a nitrogen stream. After the reaction was completed, the mixture was extracted with toluene, and the organic layer was concentrated to dryness. The resulting solid was purified by silica gel column chromatography (toluene:ethyl acetate mixture) to obtain 1.9 g (yield: 54%) of a yellow solid m-6.

[0166] (3) Synthesis of Compound C-1 The following reagents and solvents were placed in a 200 ml recovery flask. Compound m-6: 1.8g (5.0mmol) THF: 70ml Next, the reaction solution was cooled to -78°C under a nitrogen stream, and 8.3 ml of nBuLi (0.6 M) was added dropwise. After the addition, the reaction solution was stirred at room temperature for 2 hours. The reaction solution was again cooled to -78°C, and 10 ml of a THF solution containing 1.4 g (5.0 mmol) of compound m-3 was added dropwise. After the addition, the reaction solution was stirred at room temperature for 4 hours. After the reaction, the mixture was poured into ice water and extracted with toluene. The organic layer was concentrated to dryness to obtain a solid.

[0167] Next, the solid was dissolved in 80 ml of acetic acid under a nitrogen stream, and 1.5 ml of concentrated hydrochloric acid was added dropwise at room temperature. The reaction solution was stirred at room temperature for 5 hours. After the reaction was completed, the reaction solution was poured into ice water, and the precipitated solid was filtered. The filtered solid was purified by silica gel column chromatography (toluene:ethyl acetate mixture) to obtain 1.2 g of exemplary compound C-1 (yield: 22%).

[0168] Exemplary Compound C-1 was subjected to mass spectrometry using MALDI-TOF-MS (Autoflex LRF, manufactured by Bruker). [MALDI-TOF-MS] Measured value: m / z=526 Calculated value: C 38 H 23 NO2=526

[0169] Examples 2 to 14 (Synthesis of Exemplary Compounds) (Example 7 is a reference example) ] As shown in Tables 2 and 3, the exemplary compounds shown in Examples 2 to 14 were synthesized in the same manner as in Example 1, except that raw material m-2 in Example 1 was replaced with raw material 1, raw material m-4 with raw material 2, and raw material m-5 with raw material 3. The actual measured values ​​(m / z) of the mass spectrometry results measured in the same manner as in Example 1 are also shown.

[0170] [Table 2]

[0171] [Table 3]

[0172] [Example 15] In this example, a bottom-emission organic EL device was fabricated in which an anode, a hole injection layer, a hole transport layer, an electron blocking layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode were sequentially formed on a substrate.

[0173] First, an ITO film was formed on a glass substrate and then patterned as desired to form an ITO electrode (anode). At this time, the film thickness of the ITO electrode was set to 100 nm. The substrate on which the ITO electrode was formed was used as the ITO substrate in the following steps. Next, vacuum deposition was performed by resistance heating in a vacuum chamber to successively form the organic compound layer and electrode layer shown in Table 4 on the ITO substrate. At this time, the electrode area of ​​the opposing electrode (metal electrode layer, cathode) was set to 3 mm2. 2 The "% ratio" in Table 4 is a mass ratio.

[0174] [Table 4]

[0175] The device characteristics were measured and evaluated. The initial light-emitting characteristics were green light emission with a maximum external quantum efficiency (EQE) of 5.8%. Specifically, the current-voltage characteristics were measured using a Hewlett-Packard 4140B microcurrent meter, and the light-emitting brightness was measured using a Topcon BM7. Furthermore, the device was heated at a current density of 50 mA / cm. 2 A continuous driving test was conducted at 122 hours, and the time (LT95) until the brightness degradation rate reached 5% was measured.

[0176] [Examples 16 to 20] An organic light-emitting device was produced in the same manner as in Example 15, except that the compounds in Example 15 were appropriately changed to those shown in Table 5. The characteristics of the obtained device were measured and evaluated in the same manner as in Example 15. The measurement results are shown in Table 5.

[0177] [Table 5]

[0178] [Example 21] An organic light-emitting device was produced in the same manner as in Example 15, except that the organic compound layer and electrode layer shown in Table 6 were successively formed. In Table 6, "ratio %" denotes a mass ratio.

[0179] [Table 6]

[0180] The device characteristics were measured and evaluated in the same manner as in Example 20. As the initial light-emitting characteristics, green light emission with a maximum external quantum efficiency (EQE) of 6.9% was obtained. Furthermore, at a current density of 50 mA / cm 2 A continuous driving test was conducted at 1000 rpm, and the time until the brightness degradation rate reached 5% (LT95) was measured, which was 158 hours.

[0181] [Examples 22 to 38, Comparative Examples 1 and 2] An organic light-emitting device was produced in the same manner as in Example 21, except that the compounds in Example 21 were appropriately changed to those shown in Table 7. The characteristics of the obtained device were measured and evaluated in the same manner as in Example 21. The measurement results are shown in Table 7. The guest materials used in the comparative examples are shown below.

[0182] [ka]

[0183] [Table 7]

[0184] As shown in Table 7, the maximum external quantum efficiency (EQE) of Comparative Examples 1 and 2 is low, at 4.0 or less. This is because the difference between S1 and T1 is large, resulting in the absence of light-emitting components due to delayed fluorescence. On the other hand, the device using the compound of the present invention has an acridine ring and a ring having a carbonyl group via a spiro structure, resulting in a small difference between S1 and T1, and exhibits highly efficient light emission due to light emission due to delayed fluorescence. Furthermore, the device using the compound of the present invention exhibited good durability characteristics, with a 5% degradation life (LT95) of 100 hours or more. [Explanation of symbols]

[0185] 1: interlayer insulating layer, 2: first electrode, 3: insulating layer, 4: organic compound layer, 5: second electrode, 6: protective layer, 7: color filter, 10: subpixel, 11: substrate, 12: insulating layer, 13: gate electrode, 14: gate insulating film, 15: semiconductor layer, 16: drain electrode, 17: source electrode, 18: TFT, 19: insulating film, 20: contact hole, 21: anode, 22: organic compound layer, 23: cathode, 24: first protective layer, 25: second protective layer, 26: organic light-emitting element, 100: display device< / z> < / y>

Claims

1. An organic compound represented by the following general formula [1] or [2]: 【Chemical 1】 In formula [1] or [2], X 1 ~X 18 , X 21 ~X 38 are each independently selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a silyl group. 1 ~X 18 , X 21 ~X 38 In the formula (I), when the alkyl group or the aryl group has a substituent, the substituent is a halogen atom, an alkyl group, or an aryl group. Y is oxygen, sulfur, selenium, tellurium, Cr 1 R 2 R represents either a hydroxyl group or a carbonyl group. 1 ~R 2 are each independently selected from a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a silyl group. 1 ~R 2 In the formula (I), when the alkyl group or the aryl group has a substituent, the substituent is a halogen atom, an alkyl group, or an aryl group. Z represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a substituted or unsubstituted heterocyclic group.

2. The X 1 ~X 18 , X 21 ~X 38 2. The organic compound according to claim 1, wherein each of the groups is independently selected from a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, and a silyl group.

3. The X 1 ~X 18 , X 21 ~X 38 is a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group, a substituent on the alkyl group or the aryl group is an alkyl group or an aryl group, The R 1 ~R 2 3. The organic compound according to claim 1, wherein when either of the groups is a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, a substituent of the alkyl group or the aryl group is an alkyl group or an aryl group.

4. 4. The organic compound according to claim 1, wherein Y is oxygen or sulfur.

5. 5. The organic compound according to claim 1, wherein Z is a substituted or unsubstituted aryl group.

6. an anode and a cathode, an organic compound layer disposed between the anode and the cathode, An organic light-emitting device, wherein at least one of the organic compound layers comprises the organic compound according to claim 1 .

7. 7. The organic light-emitting element according to claim 6, wherein the layer containing the organic compound is a light-emitting layer.

8. The organic light-emitting device according to claim 7 , wherein the light-emitting layer further comprises a host material.

9. The organic light-emitting device according to claim 8 , wherein the host material is a hydrocarbon compound.

10. The organic light-emitting device according to claim 8 or 9, wherein the light-emitting layer further comprises a light-emitting material.

11. The organic light-emitting device according to claim 10, wherein the light-emitting material is a hydrocarbon compound.

12. 12. The organic light-emitting device according to claim 7, wherein the light-emitting layer emits green or red light.

13. A display device comprising a plurality of pixels, at least one of the plurality of pixels comprising the organic light-emitting element according to claim 6 and an active element connected to the organic light-emitting element.

14. an optical unit having a plurality of lenses, an image pickup element that receives light that has passed through the optical unit, and a display unit that displays an image picked up by the image pickup element; The photoelectric conversion device, wherein the display section comprises the organic light-emitting element according to claim 6 .

15. 13. An electronic device comprising: a display unit having the organic light-emitting element according to claim 6; a housing in which the display unit is provided; and a communication unit provided in the housing and communicating with an external device.

16. 13. A lighting device comprising: a light source having the organic light-emitting element according to claim 6; and a light diffusion section or an optical filter that transmits light emitted by the light source.

17. A moving body comprising: a lamp having the organic light-emitting element according to claim 6; and a vehicle on which the lamp is provided.

18. An exposure light source for an electrophotographic image forming apparatus, comprising the organic light-emitting element according to claim 6 .

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