Organic compound, organic light-emitting element, display device, photoelectric conversion device, electronic device, lighting device, moving body, and exposure light source

Abstract

To provide an organic compound excellent in luminous efficiency.SOLUTION: An organic compound is expressed by a formula below: (X is one of O, S, Se and Te. R1 to R18 are respectively selected independently from H, 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 aromatic hydrocarbon group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted silyl group, and a cyano group.).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an organic compound, an organic light-emitting element, a display device, a photoelectric conversion device, an electronic device, a lighting device, a moving body, and an exposure light source.

Background Art

[0002] An organic light-emitting element (hereinafter sometimes referred to as an "organic electroluminescence element" or an "organic EL element") is an electronic element having a pair of electrodes and an organic compound layer disposed between these electrodes. By injecting electrons and holes from these 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 element emits light.

[0003] Recent progress in organic light-emitting elements has been remarkable, and its features include low driving voltage, various emission wavelengths, high-speed responsiveness, and the ability to make the light-emitting device thinner and lighter.

[0004] Regarding the improvement of the efficiency of organic light-emitting elements, elements using high-efficiency materials such as phosphorescent materials and delayed fluorescence materials have been reported. Compound 1-a below is described in Patent Document 1, and Compound 2-a below is described in Patent Document 2, respectively.

[0005]

Chemical Formula

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] When Compound 1-a described in Patent Document 1 or Compound 2-a described in Patent Document 2 is used in the light-emitting layer of an organic light-emitting device, there are still problems with luminous efficiency.

[0008] The present invention has been made in view of the above problems, and an object thereof is to provide an organic compound having excellent luminous efficiency.

Means for Solving the Problems

[0009] The organic compound according to one aspect of the present invention is characterized by being represented by the following general formula [1-1].

[0010]

Chemical formula

[0011] (In General Formula [1-1], X is any one of an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom. R 1 ~R 18 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 aromatic hydrocarbon group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted silyl group, and a cyano group.)

Effects of the Invention

[0012] According to the present invention, an organic compound having excellent luminous efficiency can be provided.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0014] ≪Organic Compound≫ First, the organic compound according to the present embodiment will be described. The organic compound according to the present embodiment is represented by the following general formula [1-1].

[0015]

Chemical Formula

[0016] (In general formula [1-1], X is any one of an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom. R 1 ~R 19 are a hydrogen atom, Fluorine atom, a substituted or unsubstituted alkyl group 、 a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted Carbazole group , Trimethyl silyl group, TriphenylThey are each independently selected from a group consisting of a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 60 carbon atoms, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted silyl group, and a cyano group. When the alkyl group, aromatic hydrocarbon group, and carbazole group have substituents, the substituents are each independently selected from an alkyl group, an aralkyl group, an aryl group, and a fluorine atom. )

[0017] In general formula [1-1], R 1 ~R 18 is preferably each independently selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 60 carbon atoms, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted silyl group, and a cyano group.

[0018] In general formula [1-1], X is preferably any one of an oxygen atom, a sulfur atom, and a selenium atom, and more preferably an oxygen atom or a sulfur atom.

[0019] R 1 ~R 18 Suitable halogen atoms for R

[0020] R 1 ~R 18 include, but are not limited to, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc. Suitable alkyl groups for R

[0021] R 1 ~R 18 include, but are not limited to, a methyl group, an ethyl group, a normal propyl group, an isopropyl group, a normal butyl group, a tertiary butyl group, a secondary butyl group, an octyl group, a cyclohexyl group, a 1-adamantyl group, a 2-adamantyl group, etc. Suitable alkoxy groups for R

[0022] R 1 ~R 18Suitable amino groups include, but are not limited to, N-methylamino group, N-ethylamino group, N,N-dimethylamino group, N,N-diethylamino group, N-methyl-N-ethylamino group, N-benzylamino group, N-methyl-N-benzylamino group, N,N-dibenzylamino group, anilino group, N,N-diphenylamino group, N,N-dinaphthylamino group, N,N-difluorenylamino group, N-phenyl-N-tolylamino group, N,N-ditolylamino group, N-methyl-N-phenylamino group, N,N-dianisorylamino group, N-mesityl-N-phenylamino group, N,N-dimesitylamino group, N-phenyl-N-(4-tert-butylphenyl)amino group, N-phenyl-N-(4-trifluoromethylphenyl)amino group, N-piperidyl group, carbazolyl group, acridyl group, etc.

[0023] R 1 ~R 18 Suitable aromatic hydrocarbon groups include, but are not limited to, phenyl group, naphthyl group, indenyl group, biphenyl group, terphenyl group, fluorenyl group, phenanthryl group, triphenylenyl group, pyrenyl group, anthranyl group, perylenyl group, chrysenyl group, fluoranthenyl group, etc.

[0024] R 1 ~R 18 Suitable heterocyclic groups include, but are not limited to, pyridyl group, pyrimidyl group, pyrazyl group, triazyl group, benzofuranyl group, benzothiophenyl group, dibenzofuranyl group, dibenzothiophenyl group, oxazolyl group, oxadiazolyl group, thiazolyl group, thiadiazolyl group, carbazolyl group, acridinyl group, phenanthrollyl group, etc.

[0025] R 1 ~R 18 Suitable aryloxy groups include, but are not limited to, phenoxy group, thienyloxy group, etc.

[0026] R 1 ~R18 Examples of suitable silyl groups include, but are not limited to, trimethylsilyl group, triphenylsilyl group, etc.

[0027] Examples of the substituents that the above alkyl group, alkoxy group, amino group, aryl group, heterocyclic group, aryloxy group, and silyl group may further have include alkyl groups such as methyl group, ethyl group, normal propyl group, isopropyl group, normal butyl group, and tertiary butyl group, aralkyl groups such as benzyl group, aryl groups such as phenyl group and biphenyl group, heterocyclic groups such as pyridyl group and pyrrolyl group, amino groups such as dimethylamino group, diethylamino group, dibenzylamino group, diphenylamino group, and ditolylamino group, alkoxy groups such as methoxy group, ethoxy group, and propoxy group, aryloxy groups such as phenoxy group, halogen atoms such as fluorine, chlorine, bromine, and iodine, and cyano group, etc., but are not limited thereto.

[0028] Next, a method for synthesizing the organic compound according to this embodiment will be described. The organic compound according to this embodiment is synthesized, for example, according to the reaction scheme shown below.

[0029]

Chemical formula

[0030] Here, in the above reaction scheme, by appropriately changing the compounds shown in (a) to (c), various compounds represented by the general formula [1-1] in which the substituents of X and R 1 ~R 18 are different can be obtained. Note that the synthesis method is not limited to this. Specific synthesis methods will be described in detail in the examples.

[0031] Next, the characteristics of the organic compound according to the present embodiment will be described. The organic compound according to the present embodiment has the following characteristics. By using the organic compound according to the present embodiment in an organic light-emitting element, an organic light-emitting element excellent in luminous efficiency can be provided. In the following description, the basic skeleton means that R 1 ~R 18 in the compound represented by the general formula [1-1] are all substituted with hydrogen atoms.

[0032] Hereinafter, the characteristics of the present invention will be described while comparing with Comparative Compound 1-a described in Patent Document 1 using Exemplary Compound A1 which is a compound represented by the general formula [1-1].

[0033]

Chemical Formula

[0034] (1) Since the basic skeleton has an asymmetric structure, the oscillator strength is high and the luminous efficiency is high.

[0035] In an organic compound, the higher the transition probability between the ground state and the excited state, the higher the luminous efficiency when the organic compound is used as a light-emitting material. The oscillator strength is known as one of the indices of the transition probability between the ground state and the excited state. The larger the oscillator strength, the higher the transition probability between the ground state and the excited state, and the higher the luminous efficiency.

[0036] The inventors of the present invention focused on the presence or absence of the symmetry axis of the compound and the transition dipole moment in creating the organic compound represented by the general formula [1-1]. Further, in order to estimate the transition dipole moment, the electron distributions of HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital) were calculated, and their centroids were obtained. The calculation results for Comparative Compound 1-a and Exemplary Compound A1 are shown in Table 1. In the structural formula of Table 1, the centroid position of HOMO is indicated by a black circle, and the centroid position of LUMO is indicated by a square mark (black diamond).

[0037]

Table 1

[0038] As shown in Table 1, Comparative Compound 1-a has a molecular structure that is symmetric at a partial rotational position of the phenyl group bonded to the nitrogen atom. In that case, the center of gravity of the electron distribution of the HOMO and the center of gravity of the electron distribution of the LUMO both exist on this axis of symmetry. Therefore, the transition dipole moment from the HOMO to the LUMO is inhibited, and the transition probability between the ground state and the excited state decreases. When the oscillator strength was calculated for Comparative Compound 1-a, the oscillator strength was 0.

[0039] On the other hand, Exemplary Compound A1 according to this embodiment has a condensed ring structure in which the phenyl group bonded to the nitrogen atom is bonded to another aromatic ring via an oxygen atom. Therefore, it has an asymmetric molecular structure in which the axis of symmetry possessed by Comparative Compound 1-a does not exist. Further, by using a chalcogen atom such as an oxygen atom, a sulfur atom, a selenium atom, or a tellurium atom as the substituent X in the general formula [1-1], the electron orbit of the HOMO is also distributed on X. Actually, as shown in Table 1, in Exemplary Compound A1, the electron orbital distribution of the HOMO also exists on the oxygen atom. As a result, the center of gravity of the electron orbital distribution of the HOMO shifts toward the oxygen atom and deviates from the axis of symmetry in Comparative Compound 1-a. Thereby, the transition dipole moment from the HOMO to the LUMO also deviates from the above axis of symmetry, and a decrease in the transition probability between the ground state and the excited state is suppressed. When the oscillator strength was calculated for Exemplary Compound A1, the oscillator strength was 3×10 -4 and it became a value larger than that of Comparative Compound 1-a.

[0040] From the above, not only Exemplary Compound A1 but also the organic compounds according to this embodiment all have an asymmetric structure in the basic skeleton. Therefore, the transition dipole moment is not inhibited, the oscillator strength is high, and the light emission efficiency is high.

[0041] (2) Since the basic skeleton does not have a rotation axis, loss of excitation energy is suppressed and the light emission efficiency is high.

[0042] Furthermore, in creating the organic compound represented by the general formula [1-1], the present inventors focused on the presence or absence of a rotation axis in the basic skeleton of the compound.

[0043] When a molecule generates an excited state from light or electrical stimulation and then emits light and returns to the ground state, from the viewpoint of luminescence efficiency, it is desirable that all of the given energy be used for luminescence. However, in reality, a part of the excitation energy is lost as the vibrational energy of the molecule. Therefore, the luminescence efficiency decreases by the amount of the lost energy. Thus, in order to suppress the loss due to molecular vibration and improve the luminescence efficiency, it is preferable that the basic skeleton involved in the luminescence process does not have a bond rotation axis.

[0044] As shown in Table 1, Comparative Compound 1-a has a phenyl group bonded only to a nitrogen atom within the basic skeleton. This phenyl group rotates about the bond axis between the carbon atom bonded to the nitrogen atom and the nitrogen atom. Therefore, in Comparative Compound 1-a, energy loss due to rotational vibration occurs, and the luminescence efficiency decreases.

[0045] On the other hand, as shown in Table 1, Exemplary Compound A1 according to the present embodiment has a condensed ring structure in which a phenyl group bonded to a nitrogen atom is bonded to another aromatic ring via an oxygen atom. Therefore, the rotation of the phenyl group is restricted, and there is no rotation axis that existed in Exemplary Compound 1-a. Thus, energy loss due to vibration is suppressed, and high-efficiency luminescence is obtained.

[0046] From the above, the organic compound according to the present invention, not limited to Exemplary Compound A1, has a structure that does not have a rotation axis in any state as the basic skeleton. Therefore, energy loss due to vibration is suppressed, and the luminescence efficiency is high.

[0047] In this specification, the electron orbital distributions of HOMO and LUMO, oscillator strength, singlet excited state (S 1 ) and triplet excited state (T 1)'s energy was calculated and visualized using molecular orbital calculations. As the calculation method of the molecular orbital calculation method, the currently widely used density functional theory (DFT) was used. The functional is B3LYP and the basis function is 6-31G *It was used. The molecular orbital calculation method was carried out using Gaussian09 (Gaussian09, 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. Hasegawa, 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. Klene, J.E. Knox, J.B. Cross, V. Bakken, C. Adamo, J. Jaramillo, R. Gomperts, 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.). Thereafter, the molecular orbital calculations in this specification were performed using the same method.

[0048] (3) Since the basic skeleton has a condensed ring structure, dissociation due to bond cleavage is less likely to occur, and the durability is high.

[0049] Compounds in the organic layer of the organic light-emitting device, particularly in the light-emitting layer, repeatedly transition between the ground state and the excited state during the light-emitting process of the organic light-emitting device. During this process, intense molecular stretching, rotation, and other movements occur. At this time, if there are sites where bonds are likely to dissociate, the bonds may cleave and part of the compound may become free. When part of the compound becomes free, the structure changes, so the compound is likely to dissociate and its durability as a compound decreases. In addition, when such a compound is used in an organic light-emitting device, the free part becomes a quencher and reduces the device durability. Therefore, the more a molecule has a structure in which bonds are difficult to dissociate and dissociation is less likely to occur, the better the durability.

[0050] As shown in Table 2, when the C-N bond in the portion surrounded by the broken line of Comparative Compound 1-a cleaves, the phenyl group after cleavage is not bonded to other parts of the compound, so it is difficult to re-bond and return to the original compound. Therefore, when cleavage occurs, part of the compound is likely to become free and the structure is likely to change. As a result, the durability decreases.

[0051] On the other hand, in Exemplary Compound A1 according to the present embodiment, even when the C-N bond in the portion surrounded by the broken line cleaves, the phenyl group after cleavage remains bonded to other parts of the compound by a condensed ring structure via an oxygen atom. Therefore, the phenyl group does not become free and remains near the nitrogen atom that was bonded before the C-N bond cleaved, so it is easy to re-bond and return to the original structure. Therefore, the organic compound according to the present embodiment is less likely to dissociate due to bond cleavage than Comparative Compound 1-a, and has high durability. Therefore, when the compound according to the present embodiment is used in the organic layer of an organic light-emitting device, dissociation due to bond cleavage during device driving is less likely to occur, so even when driven for a long time, device degradation is suppressed, and an organic light-emitting device with excellent durability can be obtained.

[0052]

Table 2

[0053] (4) Since the basic skeleton has an asymmetric structure and a condensed ring structure, molecular association is unlikely to occur and the thermal stability is high.

[0054] During the driving of the organic light-emitting device, part of the injected electrical energy can be released as thermal energy in the organic layer. Therefore, if the thermal stability of the compound contained in the organic layer is low, the dissociation of the bond as described above is likely to occur due to the released thermal energy. In addition, crystallization of the organic film can also occur due to the released thermal energy. The dissociation of the bond and the crystallization of the organic film lead to a decrease in device durability. Therefore, by using a compound having good film properties and high thermal stability, the device durability can be improved.

[0055] As described above, Comparative Compound 1-a has a symmetric structure in its basic skeleton. Therefore, molecules are likely to be regularly arranged in the film, and the crystallinity of the film tends to be high. That is, crystallization is likely to occur. In addition, since Comparative Compound 1-a does not have a condensed ring structure such as Exemplary Compound A1, the bond is likely to cleave and a part in the molecule is likely to be released, resulting in low thermal stability.

[0056] On the other hand, Exemplary Compound A1 according to the present embodiment has an asymmetric structure in its basic skeleton. Therefore, molecules are unlikely to be regularly arranged in the film, the crystallinity of the film is low, and an amorphous film can be formed. That is, crystallization is unlikely to occur. As a result, the film formed by Exemplary Compound A1 according to the present embodiment has good film properties. Even when driven for a long time, crystallization is unlikely to occur, and an organic light-emitting device excellent in durability can be obtained. In addition, since Exemplary Compound A1 has a condensed ring structure, the bond is unlikely to cleave and a part in the molecule is unlikely to be released, resulting in high thermal stability.

[0057] In addition, since the basic skeleton has an asymmetric structure, there is also an effect that molecular association is unlikely to occur. Thereby, when the compound of the present embodiment is used in the light-emitting layer of the organic light-emitting device, molecular association is unlikely to occur, so concentration quenching is unlikely to occur, and an organic light-emitting device with high-efficiency light emission can be obtained.

[0058] Furthermore, since the basic skeleton has an asymmetric structure, it also has the effect of improving sublimability. The improvement of sublimability enables the purification of materials by sublimation purification and the fabrication of organic light-emitting devices by vapor deposition. As a result, impurities contained in the organic light-emitting device can be reduced, and it is possible to prevent a decrease in luminous efficiency and a decrease in driving durability due to impurities.

[0059] Next, further features of the present invention will be described using exemplary compound A1, which is a compound represented by general formula [1-1], while comparing it with comparative compound 2-a described in Patent Document 2.

[0060]

Chemical formula

[0061] (5) Since the basic skeleton has an asymmetric structure and has a chalcogen atom in the basic skeleton, S 1 and T 1 have a small energy gap and high luminous efficiency.

[0062] The present inventors have found that the luminous efficiency is further improved by making the HOMO distributed on the chalcogen atom, particularly in the molecule. Chalcogen atoms such as oxygen atoms, sulfur atoms, selenium atoms, and tellurium atoms are atoms with a heavier mass than carbon atoms. By distributing the HOMO on a chalcogen atom heavier than a carbon atom in this way, the transition from the excited triplet state to the excited singlet state is promoted by the heavy atom effect of the chalcogen atom. As a result, delayed fluorescence type emission that causes molecules in the excited triplet state to transition to the excited singlet state and emit light can be generated with high efficiency.

[0063] Table 3 shows the electron distributions of HOMO and LUMO and S 1 and T 1The calculation results of the energy are shown. As shown in Table 3, in the exemplary compound A1 according to the present embodiment, the HOMO is also distributed on the oxygen atom arranged in the basic skeleton. Therefore, in the compound according to the present embodiment, the transition from the excited triplet state to the excited singlet state is promoted, and the luminescence efficiency is increased. On the other hand, the exemplary compound 2-a has no chalcogen atom, and the HOMO is not distributed on the carbon atom arranged at the position corresponding to the chalcogen atom of the exemplary compound A1. Therefore, the transition from the excited triplet state to the excited singlet state is not promoted, and the luminescence efficiency is low.

[0064] Further, in the exemplary compound A1, since the HOMO is also distributed on the oxygen atom, the center of gravity of the HOMO is shifted toward the oxygen atom. Therefore, as indicated by the dashed line in Table 3, in the comparative compound 2-a, the HOMO is also distributed on the spiro carbon atom in the anthraquinone moiety, but in the exemplary compound A1, the HOMO is not distributed on the spiro carbon atom in the anthraquinone moiety. As a result, in the exemplary compound A1, the portion where the LUMO is distributed and the portion where the HOMO is distributed in the molecule are separated, and the portion where both the LUMO and the HOMO are distributed is small. This leads to a decrease in the overlap integral and a decrease in the energy difference between the excited singlet state (S 1 ) and the excited triplet state (T 1 ), which is preferable from the viewpoint of the luminescence efficiency of the delayed fluorescence type.

[0065] Actually, as shown in Table 3, the energy gap (ΔST = T 1 - S 1 ) between the excited singlet state (S 1 ) and the excited triplet state (T 1 ) is smaller for the exemplary compound A1 than for the comparative compound 2-a. Therefore, the exemplary compound A1 has a higher luminescence efficiency than the exemplary compound 2-a.

[0066]

Table 3

[0067] (6) Since it has a low LUMO, its stability against oxygen is high and its durability is high.

[0068] In an organic semiconductor, in the case of a compound having a similar band gap, the lower the HOMO-LUMO level (farther from the vacuum level), the higher the stability against oxygen. Therefore, by lowering the energy level of the LUMO, the stability against oxygen is increased, and the durability of the compound itself and the durability of the organic light-emitting element are improved.

[0069] Therefore, the inventors focused on the LUMO. Table 4 summarizes the molecular structures and the results of molecular orbital calculations (S 1 , T 1 , ΔST, LUMO) of exemplary compounds A1, B1, C1 which are examples of the compounds represented by the general formula [1-1], comparative compound 1-a, and reference compound D1. As shown in Table 4, it was found that the compounds A1, B1, C1 according to the present embodiment have a lower LUMO (farther from the vacuum level) than the comparative compound 1-a.

[0070] In order to lower the LUMO, it is necessary to attract and stabilize the electrons in the LUMO orbit. However, an amino group which is an electron-donating group is bonded immediately adjacent to the anthraquinone moiety which bears the LUMO as in the comparative compound 1-a. Therefore, due to the electron-donating property of the amino group, the LUMO becomes high. On the other hand, in the compound of the present invention, by forming the amine moiety which bears the HOMO into a condensed ring structure, the electron-donating property to the anthraquinone moiety which bears the LUMO is suppressed and the LUMO is stabilized. Therefore, since the compound of the present embodiment has a low LUMO, its stability against oxygen is high and the element durability is high.

[0071]

Table 4

[0072] Furthermore, the compound of the present embodiment is preferably used in the light-emitting layer in an organic light-emitting element, and in that case, it has the following characteristics.

[0073] (7) 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.

[0074] (8) By mixing the compound of this embodiment with a host material in the light-emitting layer and further having a light-emitting material, a highly efficient and high-color-purity light-emitting device is provided.

[0075] (9) When the light-emitting material is a compound composed of hydrocarbons, a highly efficient and durable light-emitting device is provided.

[0076] Hereinafter, the features (7) to (9) above will be described.

[0077] (7) 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.

[0078] The compound of this embodiment is a compound having an electron-withdrawing carbonyl group and an electron-donating amino group. Therefore, by mixing with a host material (second organic compound) in the light-emitting layer of an organic light-emitting device, a light-emitting layer with electron-trapping properties due to the contribution of electron-withdrawing, or a light-emitting layer with hole-trapping properties due to the contribution of electron-donating is formed.

[0079] Therefore, electrons or holes supplied from the transport layer in the light-emitting layer are trapped by the compound of this embodiment, and exciton recombination occurs. As described in the above feature (5), the compound of this embodiment has an S 1 and T 1 Since the energy difference (ΔST) is small, efficient delayed fluorescence-type emission occurs in the light-emitting layer, and more triplet excitons can be utilized for emission.

[0080] In particular, when the host material is a hydrocarbon compound, the LUMO of the compound of the present embodiment tends to be at a lower level (farther from the vacuum level) than the host material, or the HOMO of the compound of the present embodiment tends to be at a higher level (closer to the vacuum level) than the host material. Therefore, it is easier to trap electrons and holes, resulting in a greater effect. Here, a hydrocarbon compound is a compound whose molecules are composed of only carbon and hydrogen.

[0081] Furthermore, the compound of the present embodiment has a spiro site, and as described in (4), the basic skeleton has an asymmetric structure and a fused-ring structure. Therefore, molecular aggregation is less likely to occur, and concentration quenching is less likely to occur in the host material. This effect leads to preventing quenching due to the interaction between excitons when the compound of the present embodiment is in an excited state, and is effective in efficiently generating delayed fluorescence emission in the light-emitting layer.

[0082] (8) By mixing the compound of the present embodiment with a host material in a light-emitting layer and further having a light-emitting material, a light-emitting device with high efficiency and high color purity is provided.

[0083] By using the compound of the present embodiment in a light-emitting layer and further doping a light-emitting material with a high photoluminescence quantum yield or a light-emitting material (a third organic compound) having a spectrum suitable for showing high color purity in the emission spectrum as a light-emitting material, a light-emitting device with even higher efficiency and high color purity is provided. At this time, the compound of the present embodiment functions as an assist material. In this case, since the compound of the present embodiment facilitates exciton recombination, it is preferably configured at a concentration such that electrons and holes can be preferentially trapped in the light-emitting layer. Therefore, the concentration of the organic compound according to the present 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 with respect to the entire light-emitting layer.

[0084] On the one hand, when the compound of the present embodiment is regarded as a luminescent material, a lower doping concentration is preferred because it is less susceptible to concentration quenching due to intermolecular interactions and changes in the emission spectrum. Therefore, it is preferable to dope a luminescent material other than the compound of the present embodiment in the light-emitting layer. The doping concentration of the luminescent material to be further doped in the light-emitting layer is preferably 0.01% by mass or more and 20% by mass or less, more preferably 1% by mass or more and 15% by mass or less, based on the entire light-emitting layer. Thus, a light-emitting device with high efficiency and high color purity can be provided.

[0085] (9) When the luminescent material is a compound composed of hydrocarbons, a light-emitting device with high efficiency and good durability is provided.

[0086] Since the compound of the present embodiment has a strongly electron-withdrawing carbonyl group, as described in (8) above, the luminescent material doped and used together in the light-emitting layer is preferably a luminescent material having no amino group, which is an electron-donating group, and more preferably a compound composed of hydrocarbons. The reason is as follows. When a luminescent material having an amino group is used together with the compound of the present embodiment, the amino group and the carbonyl group of the compound of the present embodiment in the light-emitting layer interact with each other. As a result, the luminescence efficiency may decrease due to exciplex formation, or the color purity of the light-emitting device may decrease due to a change in the emission spectrum of the luminescent material.

[0087] Furthermore, since a luminescent material having an amino group has a low ionization potential, it is easily oxidized and has low device durability. Therefore, the luminescent material is preferably a compound composed of hydrocarbons, more preferably a condensed polycyclic compound having a 5-membered ring. This is because a structure with a higher ionization potential is less likely to be oxidized. Here, a hydrocarbon compound is a compound whose molecules are composed of only carbon and hydrogen.

[0088] As described above, by mixing the compound of the present embodiment with a host material in a light-emitting layer, an organic light-emitting device with high-efficiency light emission can be obtained. At this time, the light-emitting material may be the compound of the present embodiment, or in addition to the compound of the present embodiment, another light-emitting material may be further mixed, and the compound of the present 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. Further, when the host material is a hydrocarbon compound, the compound of the present embodiment is likely to trap electrons and holes, so the effect of improving efficiency is greatly preferable.

[0089] Next, among the compounds represented by the general formula [1-1], more preferable compounds will be described.

[0090] In the general formula [1-1], a compound in which X is an oxygen atom is preferable because the energy of S 1 becomes a value suitable as a green light-emitting material. In other words, it is preferably a compound represented by the following general formula [2-1]. As shown in Table 4, for the exemplified compound A1 in which R 1 ~R 18 are all hydrogen atoms in the following general formula [2-1], the energy of S 1 is 461 nm and shows green light emission.

[0091]

Chemical formula

[0092] In the general formula [2-1], R 1 ~R 18 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 aromatic hydrocarbon group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted silyl group, and a cyano group.

[0093] In the general formula [2-1], R 1 ~R 18is preferably independently selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 60 carbon atoms, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted silyl group, and a cyano group. Note that R 1 ~R 18 Examples of suitable substituents are as described above.

[0094] In general formula [1-1], a compound in which X is a sulfur atom or a selenium atom is preferable because the energy of S 1 becomes a suitable value as a blue light-emitting material. In other words, it is preferably a compound represented by the following general formula [2-2] or the following general formula [2-3]. As shown in Table 4, in the following general formula [2-2], when R 1 ~R 18 are all hydrogen atoms, exemplified compound B1 is a compound in which the energy of S 1 is 432 nm and shows blue light emission. Also, in the following general formula [2-3], when R 1 ~R 18 are all hydrogen atoms, exemplified compound C1 is a compound in which the energy of S 1 is 432 nm and shows blue light emission.

[0095] Furthermore, among the compounds represented by general formula [1-1], a compound in which X is a sulfur atom, that is, a compound represented by general formula [2-2], has the characteristic that the LUMO is lower and is preferable.

[0096]

Chemical formula

[0097] In general formula [2-2], R 1 ~R 18is 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 aromatic hydrocarbon group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted silyl group, and a cyano group.

[0098] In General Formula [2-2], R 1 ~R 18 is preferably independently selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 60 carbon atoms, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted silyl group, and a cyano group. Note that examples of preferred substituents for R 1 ~R 18 are as described above.

[0099]

Chemical formula

[0100] In General Formula [2-3], R 1 ~R 18 is 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 aromatic hydrocarbon group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted silyl group, and a cyano group.

[0101] In General Formula [2-3], R 1 ~R 18is preferably independently selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 60 carbon atoms, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted silyl group, and a cyano group. Here, R 1 ~R 18 Examples of suitable substituents are as described above.

[0102] Reference compound D1 in Table 3 is an example of a compound in which X in general formula [1-1] is substituted with CR 19 R 20 Here, R 19 ~R 20 is 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 aromatic hydrocarbon group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted silyl group, and a cyano group. R 19 ~R 20 is preferably independently selected from a hydrogen atom, a halogen atom, and a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms. Among them, it is preferable that R 19 ~R 20 are all methyl groups, and it is a compound represented by the following general formula [2-4].

[0103]

Chemical formula

[0104] In general formula [2-4], R 1 ~R 18is 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 aromatic hydrocarbon group, a substituted or unsubstituted heterocyclic group, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted silyl group, and a cyano group.

[0105] In General Formula [2-4], R 1 ~R 18 is preferably independently selected from a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a substituted or unsubstituted heterocyclic group having 3 to 60 carbon atoms, a substituted or unsubstituted aryloxy group, a substituted or unsubstituted silyl group, and a cyano group. Note that examples of suitable substituents for R 1 ~R 18 are as described above.

[0106] Specific examples of the organic compound according to the present invention are shown below. However, the present invention is not limited thereto.

[0107]

Chemical formula

[0108]

Chemical formula

[0109]

Chemical formula

[0110] Among the above-exemplified compounds, those belonging to Group A (Compounds A1 to A24) are compounds in which X is an oxygen atom in General Formula [1-1]. That is, they are compounds represented by General Formula [2-1]. As described above, among the compounds represented by General Formula [1-1], these compounds have a small S 1 energy. Therefore, when used in, for example, an organic light-emitting device, they can provide green light emission.

[0111] Among the above-exemplified compounds, those belonging to Group B (Compounds B1 to B24) are compounds in which X is a sulfur atom in General Formula [1-1]. That is, they are compounds represented by General Formula [2-2]. As described above, among the compounds represented by General Formula [1-1], these compounds have a low LUMO. Therefore, when used in, for example, an organic light-emitting device, they can provide good durability.

[0112] Among the above-exemplified compounds, those belonging to Group C (C1 to C12) are compounds in General Formula [1-1] in which X is a selenium atom (C1 to C11) or a tellurium atom (C12). As described above, among the compounds represented by General Formula [1-1], these compounds have a large S 1 energy. Therefore, when used in, for example, an organic light-emitting device, they can provide blue light emission.

[0113] In addition, the compounds of this embodiment have a chalcogen atom having a lone pair of electrons in the basic skeleton. This lone pair of electrons has the effect of enhancing the structural stability of the condensed basic skeleton. Therefore, the compounds of this embodiment are highly stable and excellent in durability. When the compounds of this embodiment are used in an organic light-emitting device, an organic light-emitting device having good durability can be provided.

[0114] Also, for reference, specific examples of the organic compound represented by General Formula [2-4] are shown below.

[0115] [Chemical formula]

[0116] Among the above-exemplified compounds, those belonging to Group D (D1 to D16) are compounds represented by General Formula [2-4]. These compounds have a molecular structure in which X in General Formula [1-1] is substituted with a substituent that is sterically bulkier than a chalcogen atom (here, an alkyl group). Therefore, these compounds are less likely to cause molecular association, packing between molecules is suppressed, and high-efficiency light emission can be provided.

[0117] ≪Organic Light-Emitting Device≫ Next, the organic light-emitting device of the present embodiment will be described.

[0118] The organic light-emitting device of the present embodiment has at least an anode (anode) and a cathode (cathode) which are a pair of electrodes, and an organic compound layer disposed between these electrodes. In the organic light-emitting device of the present embodiment, the organic compound layer may be a single layer or a laminate composed of a plurality of layers as long as it has a light-emitting layer.

[0119] Here, when the organic compound layer is a laminate composed of a plurality of 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. Further, the light-emitting layer may be a single layer or a laminate composed of a plurality of layers.

[0120] In the organic light-emitting device of the present embodiment, at least one layer of the organic compound layer contains the organic compound according to the present embodiment. Specifically, the organic compound according to the present embodiment is contained in any one of the above-described 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 the present embodiment is preferably contained in the light-emitting layer.

[0121] In the organic light-emitting device of the present embodiment, when the organic compound according to the present embodiment is included in the light-emitting layer, the light-emitting layer may be a layer composed only of the organic compound according to the present embodiment, or may be a layer composed of the organic compound according to the present embodiment and other compounds. Here, when the light-emitting layer is a layer composed of the organic compound according to the present embodiment and other compounds, the organic compound according to the present embodiment may be used as a host of the light-emitting layer, or may be used as a guest. It may also be used as an assist material that can be included in the light-emitting layer. Here, the host is the compound with the largest mass ratio among the compounds constituting the light-emitting layer. 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 the compound responsible for the main emission. 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 that assists the emission of the guest.

[0122] Here, when the organic compound according to the present embodiment is used as a guest of the light-emitting layer, the concentration of the guest is preferably 0.01% by mass or more and 20% by mass or less, more preferably 0.1% by mass or more and 5% by mass or less, with respect to the entire light-emitting layer. When the organic compound according to the present embodiment is used as an assist material of the light-emitting layer, the concentration of the assist material is preferably 0.1% by mass or more and 45% by mass or less, more preferably 1% by mass or more and 30% by mass or less, with respect to the entire light-emitting layer.

[0123] When the organic compound according to the present embodiment is used as a guest material of the light-emitting layer, the mass ratio (host material / guest material) of the host material (second organic compound) to the guest material, which is the organic compound of the present embodiment, is preferably 1.1 or more and 10000 or less. Further, the mass ratio is more preferably 2 or more and 1000 or less, and even more preferably 2 or more and 100 or less.

[0124] When using the organic compound according to this embodiment 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 a host (a second organic compound). The organic compound according to this embodiment tends to have a low LUMO. Therefore, by using a material having a higher LUMO than the organic compound according to this embodiment as a host, the organic compound according to this embodiment can receive more electrons supplied to the host of the light-emitting layer. When using the organic compound according to this embodiment as a guest material in the light-emitting layer, it is preferable to satisfy the following relationship. The S 1 energy (singlet energy) of the host material is S h1 , and the T 1 energy (triplet energy) of the host material is T h1 . Let the S 1 energy (singlet energy) of the guest material be S g1 , and the T 1 energy (triplet energy) of the guest material be T g1 . At this time, it is preferable to satisfy S h1 >S g1 . Further, it is more preferable to satisfy T h1 >T g1 .

[0125] When using the organic compound according to this embodiment as an assist material 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 a guest (a third organic compound). The organic compound according to this embodiment tends to have a low LUMO. Therefore, by using a material having a higher LUMO than the organic compound according to this embodiment as a light-emitting material (guest), the organic compound according to this embodiment can receive more electrons supplied to the host of the light-emitting layer, and the assist material is responsible for exciton recombination. As a result, it becomes possible to efficiently cause energy transfer to the light-emitting material (guest). When using the organic compound according to this embodiment as an assist material in the light-emitting layer, it is preferable to use a material having a lower S 1 energy (singlet energy) than the organic compound according to this embodiment as a guest material (light-emitting material). The S of the assist material1 Let the energy (singlet energy) be S a1 and the energy (triplet energy) of T 1 be T a1 When the S 1 energy (singlet energy) of the guest material is S g1 and the energy (triplet energy) of T 1 is T g1 it is preferable to satisfy S a1 > S g1 . Furthermore, it is more preferable to satisfy T a1 > T g1 . Furthermore, when the S 1 energy (singlet energy) of the host material is S h1 and the energy (triplet energy) of T 1 is T h1 it is more preferable to satisfy S h1 > S a1 > S g1 . Furthermore, it is more preferable to satisfy T h1 > T a1 > T g1 .

[0126] The 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, an element with high-efficiency and high-brightness light output and extremely high durability can be obtained. Furthermore, it has been found that when used as an assist material in the light-emitting layer, an element with high-efficiency and high-brightness light output and extremely high durability can be obtained. This light-emitting layer may be a single layer or a multilayer, and may also contain a plurality of light-emitting materials. The multilayer may be a state where a light-emitting layer and another light-emitting layer are laminated, or an intermediate layer may be laminated between a plurality of light-emitting layers. Also, it may be fluorescence emission or phosphorescence emission. Also, it may be a tandem element or a stack element. In these cases, the emission color of the organic light-emitting element is not limited to a single color. More specifically, it may be white or an intermediate color. Also, the film-forming method is not particularly limited, and film formation is performed by evaporation or coating film formation. Details of this will be described in detail in the examples described later.

[0127] The organic compound according to this embodiment can be used as a constituent material for an organic compound layer other than the light-emitting layer constituting the organic light-emitting device of this embodiment. Specifically, it may be used as a constituent material for an electron transport layer, an electron injection layer, a hole transport layer, a hole injection layer, a hole blocking layer, or the like.

[0128] <Materials Constituting the Organic Light-Emitting Device> Here, as materials constituting the organic light-emitting device, in addition to the organic compound according to this embodiment, various conventionally known low-molecular and high-molecular compounds can be used as necessary. Typically, a hole injection compound or a hole transport compound, a compound serving as a host, a light-emitting compound, an electron injection compound or an electron transport compound, etc. can be used together. Examples of these compounds are given below.

[0129] As the hole injection / transport material (hole injection material or hole transport material), a material with a high hole mobility is preferable so as to facilitate the injection of holes from the anode and transport the injected holes to the light-emitting layer. Also, in order to suppress deterioration of the film quality such as crystallization in the organic light-emitting device, a material with a high glass transition point temperature is preferable. Examples of low-molecular and high-molecular materials having hole injection / transport performance include triarylamine derivatives, arylcarbazole derivatives, phenylenediamine derivatives, stilbene derivatives, phthalocyanine derivatives, porphyrin derivatives, poly(vinylcarbazole), poly(thiophene), and other conductive polymers. Furthermore, the above hole injection / transport materials are also preferably used for the electron blocking layer.

[0130] Specific examples of the compounds used as the hole injection / transport material are shown below, but of course, they are not limited to these.

[0131]

Chemical formula

[0132] Among the hole injection and transport materials mentioned, HT16 to HT18 can reduce the driving voltage when used in the 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 the organic compound layer adjacent to HT16. Also, multiple materials may be used in one organic compound layer.

[0133] As the light-emitting materials mainly related to the light-emitting function, in addition to the organic compounds represented by the general formula [1-1], condensed ring compounds (such as fluorene derivatives, naphthalene derivatives, pyrene derivatives, perylene derivatives, tetracene derivatives, anthracene derivatives, rubrene, etc.), quinacridone derivatives, coumarin derivatives, stilbene derivatives, organic aluminum complexes such as tris(8-hydroxyquinolato)aluminum, iridium complexes, platinum complexes, rhenium complexes, copper complexes, europium complexes, ruthenium complexes, and polymer derivatives such as poly(phenylene vinylene) derivatives, poly(fluorene) derivatives, and poly(phenylene) derivatives can be mentioned.

[0134] Specific examples of the compounds used as the light-emitting materials are shown below, but of course, they are not limited to these.

[0135]

Chemical formula

[0136]

Chemical formula

[0137] When the light-emitting material is a hydrocarbon compound, it is preferable to prevent the decrease in the light-emitting efficiency due to exciplex formation and the decrease in the color purity due to the change in the emission spectrum of the light-emitting material. Here, the hydrocarbon compound is a compound composed only of carbon and hydrogen, and among the specific examples of the compounds used as the above light-emitting materials, BD7, BD8, GD5 to GD9, and RD1 correspond.

[0138] When the luminescent material is a condensed polycycle containing a five-membered ring, it has a high ionization potential, is difficult to oxidize, and is more preferable for providing an element with a highly durable lifespan. Among the specific examples of the compound used as the above luminescent material, BD7, BD8, GD5 to GD9, and RD1 correspond.

[0139] For example, by using the above luminescent material as the guest material in the light-emitting layer and using the organic compound according to this embodiment as the assist material in the light-emitting layer, an element that exhibits a highly efficient and high-brightness light output and has extremely high durability can be obtained. In this case, the color of the light emitted by the organic light-emitting element is determined by the type of the guest material that mainly bears the light emission. When compounds BD1 to BD10 are used as the guest material, a blue-light-emitting organic light-emitting element can be obtained. When compounds GD1 to GD15 are used as the guest material, a green-light-emitting organic light-emitting element can be obtained. When compounds RD1 to RD10 are used as the guest material, a red-light-emitting organic light-emitting element can be obtained.

[0140] Examples of the light-emitting layer host or the light-emitting assist material contained in the light-emitting layer include aromatic hydrocarbon compounds or their derivatives, as well as carbazole derivatives, dibenzofuran derivatives, dibenzothiophene derivatives, organoaluminum complexes such as tris(8-quinolinolato)aluminum, and organoberyllium complexes.

[0141] Specific examples of the compound used as the light-emitting layer host or the light-emitting assist material contained in the light-emitting layer are shown below, but of course, it is not limited to these.

[0142]

Chemical formula

[0143] When the host material is a hydrocarbon compound, the compound of the present invention is likely to trap electrons and holes, so the effect of improving efficiency is greatly preferable. Here, the hydrocarbon compound is a compound composed only of carbon and hydrogen, and among the specific examples of the compound used as the above host material, EM1 to EM12 and EM16 to EM27 correspond.

[0144] As the electron transporting material, it can be arbitrarily selected from those capable of transporting electrons injected from the cathode to the light emitting layer, and is selected in consideration of the balance with the hole mobility of the hole transporting material and the like. As the material having electron transporting performance, oxadiazole derivatives, oxazole derivatives, pyrazine derivatives, triazole derivatives, triazine derivatives, quinoline derivatives, quinoxaline derivatives, phenanthroline derivatives, organic aluminum complexes, condensed ring compounds (for example, fluorene derivatives, naphthalene derivatives, chrysene derivatives, anthracene derivatives, etc.) can be mentioned. Furthermore, the above electron transporting material is also preferably used for the hole blocking layer.

[0145] Specific examples of the compound used as the electron transporting material are shown below, but of course, it is not limited to these.

[0146]

Chemical formula

[0147] As the electron injecting material, it can be arbitrarily selected from those that can easily inject electrons from the cathode, and is selected in consideration of the balance with hole injection and the like. Organic compounds also include n-type dopants and reducing dopants. For example, compounds containing alkali metals such as lithium fluoride, lithium complexes such as lithium quinolinol, benzimidazolide derivatives, imidazolide derivatives, fulvalene derivatives, acridine derivatives can be mentioned.

[0148] <Structure of the organic light emitting device> The organic light emitting device 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 planarization layer may be provided between the protective layer and the color filter. The planarization layer can be composed of an acrylic resin or the like.

[0149] [Substrate] As the substrate, semiconductor substrates such as quartz, glass, and silicon wafers, resins, metals, etc. can be used. Further, the substrate may be provided with switching elements such as transistors and wirings, and an insulating layer may be provided thereon. As the insulating layer, as long as it is possible to form a contact hole to ensure conduction between the anode 2 and the wiring and to ensure insulation from non-connected wirings, the material is not limited. For example, resins such as polyimide, silicon oxide, silicon nitride, etc. can be used.

[0150] [Electrode] As the electrodes, 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. Also, it can 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.

[0151] As the constituent material of the anode, those with as large a work function as possible are good. For example, simple metals such as gold, platinum, silver, copper, nickel, palladium, cobalt, selenium, vanadium, tungsten, etc., mixtures containing these, alloys combined with these, metal oxides such as tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide, etc. can be used. Also, conductive polymers such as polyaniline, polypyrrole, polythiophene, etc. can be used.

[0152] These electrode materials may be used alone or in combination of two or more. Also, the anode may be composed of a single layer or multiple layers.

[0153] When used as a reflective electrode, for example, chromium, aluminum, silver, titanium, tungsten, molybdenum, or alloys thereof, laminated products, etc. can be used. Also, when used as a transparent electrode, oxide transparent conductive layers such as indium tin oxide (ITO), indium zinc oxide, etc. can be used, but it is not limited thereto. For the formation of the electrode, photolithography technology can be used.

[0154] On the other hand, as the constituent material of the cathode, those with a small work function are preferable. For example, alkali metals such as lithium, alkaline earth metals such as calcium, simple metals such as aluminum, titanium, manganese, silver, lead, chromium, or mixtures containing these can be mentioned. Alternatively, alloys combining these simple metals can also be used. For example, magnesium-silver, aluminum-lithium, aluminum-magnesium, silver-copper, zinc-silver, etc. can be used. The use of metal oxides such as indium tin oxide (ITO) is also possible. These electrode materials may be used alone or in combination of two or more. Also, the cathode may have a single-layer structure or a multi-layer structure. Among them, it is preferable to use silver, and in order to suppress the aggregation of silver, it is more preferable to use a silver alloy. As long as the aggregation of silver can be suppressed, the ratio of the alloy does not matter. For example, it may be 1:1.

[0155] As the cathode, an oxide conductive layer such as ITO can be used to make the organic light-emitting device a top-emission device, or a reflective electrode such as aluminum (Al) can be used as the cathode to make the organic light-emitting device a bottom-emission device, and it is not particularly limited. As the method for forming the cathode, although not particularly limited, the use of direct current and alternating current sputtering methods, etc., is more preferable because the film coverage is good and the resistance is easily reduced.

[0156] [Protective layer] After the formation of the cathode, a protective layer may be provided. For example, by adhering glass provided with a moisture absorbent on the cathode, the intrusion of water and the like into the organic compound layer can be suppressed, and the occurrence of display defects can be suppressed. Also, as another embodiment, a passivation film such as silicon nitride may be provided on the cathode to suppress the intrusion of water and the like into the organic EL layer. For example, after the formation of the cathode 7, it can be transported to another chamber without breaking the vacuum, and a silicon nitride film with a thickness of 2 μm can be formed by the CVD method to be used as a protective layer. A protective layer using the atomic layer deposition method (ALD method) may be provided after the film formation by the CVD method.

[0157] [Color filter] A color filter may be provided on the protective layer. For example, a color filter adapted to the size of the organic light-emitting element may be provided on another substrate and bonded to the substrate on which the organic light-emitting element is provided, or a color filter may be patterned on the protective layer such as silicon oxide using photolithography technology. The color filter may be composed of a polymer.

[0158] [Planarization layer] A planarization layer may be provided between the color filter and the protective layer. The planarization layer may be composed of an organic compound, and may be a low molecule or a polymer, but is preferably a polymer.

[0159] The planarization layer may be provided above and below the color filter, respectively, and the constituent materials thereof may be the same or different. Specifically, examples include polyvinylcarbazole resin, polycarbonate resin, polyester resin, ABS resin, acrylic resin, polyimide resin, phenol resin, epoxy resin, silicon resin, urea resin, and the like.

[0160] [Counter substrate] A counter substrate may be provided on the planarization layer. Since the counter substrate is provided at a position corresponding to the aforementioned substrate, it is called a counter substrate. The constituent material of the counter substrate may be the same as that of the aforementioned substrate.

[0161] [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 element according to an embodiment of the present invention are formed by the following method.

[0162] For the organic compound layers constituting the organic light-emitting element according to an embodiment of the present invention, dry processes such as vacuum evaporation, ionization evaporation, sputtering, and plasma can be used. Further, instead of the dry process, a wet process in which the layer is formed by dissolving in an appropriate solvent and using a known coating method (for example, spin coating, dipping, casting method, LB method, inkjet method, etc.) can also be used.

[0163] When a layer is formed by a vacuum evaporation method, a solution coating method, or the like, crystallization and the like hardly occur and the temporal stability is excellent. When forming a film by a coating method, a film can also be formed in combination with an appropriate binder resin.

[0164] 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, urea resin, and the like.

[0165] In addition, these binder resins may be used alone as a homopolymer or a copolymer, or two or more kinds may be mixed and used. Further, additives such as known plasticizers, antioxidants, and ultraviolet absorbers may be used in combination as necessary.

[0166] <Use of the organic light-emitting device according to the present embodiment> The organic light-emitting device according to the present embodiment can be used as a component of a display device or a lighting device. In addition, there are applications such as an exposure light source of an electrophotographic image forming device, a backlight of a liquid crystal display device, and a light-emitting device having a color filter for a white light source.

[0167] The display device may be an image information processing device that has an image input unit for inputting image information from an area CCD, a linear CCD, a memory card, etc., has an information processing unit for processing the input information, and displays the input image on a display unit. The display device may have a plurality of pixels, and at least one of the plurality of pixels may have the organic light-emitting device according to the present embodiment and a transistor connected to the organic light-emitting device. At this time, the substrate may be a semiconductor substrate such as silicon, and the transistor may be a MOSFET formed on the substrate.

[0168] In addition, the display unit included in the imaging device or the 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. Further, the display device may be used for the display unit of a multifunction printer.

[0169] Next, the display device according to the present embodiment will be described with reference to the drawings.

[0170] FIG. 1 is a cross-sectional schematic 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).

[0171] FIG. 1(a) is an example of a pixel which is a component of the display device according to the present embodiment. The pixel has a sub-pixel 10. The sub-pixel is divided into 10R, 10G, and 10B according to its light emission. The emission color may be distinguished by the wavelength emitted from the light-emitting layer, or the light emitted from the sub-pixel may be selectively transmitted or color-converted by a color filter or the like. Each sub-pixel has a reflective electrode 2 which is a first electrode on an interlayer insulating layer 1, an insulating layer 3 covering the edge of the reflective electrode 2, an organic compound layer 4 covering the first electrode and the insulating layer, a transparent electrode 5, a protective layer 6, and a color filter 7.

[0172] A transistor and a capacitive element may be arranged in the lower layer or inside the interlayer insulating layer 1. The transistor and the first electrode may be electrically connected via a contact hole or the like (not shown).

[0173] The insulating layer 3 is also called a bank or a pixel isolation film. It covers the edge of the first electrode and is arranged surrounding the first electrode. The portion where the insulating layer is not arranged is in contact with the organic compound layer 4 and becomes a light-emitting region.

[0174] The organic compound layer 4 has 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.

[0175] The second electrode 5 may be a transparent electrode, a reflective electrode, or a transflective electrode.

[0176] The protective layer 6 reduces the penetration of moisture into the organic compound layer. Although the protective layer is shown as a single layer, it may be a plurality of layers. Each layer may be an inorganic compound layer or an organic compound layer.

[0177] The color filter 7 is divided into 7R, 7G, and 7B according to its color. The color filter may be formed on a planarization film (not shown). Further, a resin protective layer (not shown) may be provided on the color filter. Also, the color filter may be formed on the protective layer 6. Alternatively, it may be bonded after being provided on a counter substrate such as a glass substrate.

[0178] The display device 100 in FIG. 1(b) includes an organic light-emitting element 26 and a TFT 18 which is an example of a transistor. A substrate 11 such as glass or silicon has an insulating layer 12 provided thereon. Active elements such as the TFT 18 are arranged 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 provided.

[0179] The TFT 18 has a semiconductor layer 15, a drain electrode 16, and a source electrode 17. An insulating film 19 is provided on the TFT 18. The anode 21 constituting the organic light-emitting element 26 and the source electrode 17 are connected via a contact hole 20.

[0180] Note that the method of electrical connection 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 is not limited to the mode shown in FIG. 1(b). That is, either one of the anode 21 or the cathode 23 and either one of the source electrode 17 or the drain electrode 16 of the TFT 18 may be electrically connected.

[0181] In the display device 100 of FIG. 1(b), the organic compound layer 22 is illustrated as a single layer, but the organic compound layer 22 may be a plurality of layers. On the cathode 23, a first protective layer 25 and a second protective layer 24 for suppressing deterioration of the organic light-emitting element are provided.

[0182] In the display device 100 of FIG. 1(b), a transistor is used as the switching element, but other switching elements such as MIM elements may be used instead.

[0183] Also, the transistor used in the display device 100 of FIG. 1(b) is not limited to a thin-film transistor having an active layer on an insulating surface of a substrate, and a transistor using a single-crystalline silicon wafer may also be used. Examples of the active layer include non-single-crystalline silicon such as single-crystalline silicon, amorphous silicon, and microcrystalline silicon, and non-single-crystalline oxide semiconductors such as indium zinc oxide and indium gallium zinc oxide. Note that a thin-film transistor is also called a TFT element.

[0184] The transistor included in the display device 100 of FIG. 1(b) may be formed in a substrate such as a Si substrate. Here, forming in the substrate means manufacturing a transistor by processing the substrate itself such as a Si substrate. That is, having a transistor in the substrate can also be regarded as the substrate and the transistor being integrally formed.

[0185] The organic light-emitting element according to this embodiment has its emission luminance controlled by a TFT which is an example of a switching element, and an image can be displayed by the emission luminance of each organic light-emitting element provided in a plurality of planes. Note that the switching element according to this embodiment is not limited to a TFT, and may be a transistor formed of low-temperature polysilicon or an active matrix driver formed on a substrate such as a Si substrate. Forming on the substrate can also mean forming in the substrate. Whether to provide a transistor in the substrate or use a TFT is selected according to the size of the display portion. For example, if the size is about 0.5 inches, it is preferable to provide an organic light-emitting element on a Si substrate.

[0186] FIG. 2 is a schematic diagram showing an example of a display device according to the present 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 to flexible printed circuits FPC 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, or may be provided at another position even if the display device is a portable device.

[0187] The display device according to the present embodiment may be used for a display unit of an imaging device having an optical unit having 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. Further, the display unit may be a display unit exposed outside the imaging device or a display unit disposed in a viewfinder. The imaging device may be a digital camera or a digital video camera. The imaging device may be alternatively referred to as an optoelectronic conversion device.

[0188] FIG. 3(a) is a schematic diagram showing an example of an imaging device according to the present 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 the display device according to the present embodiment. In that case, the display device may display not only the 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 moves, the possibility that the subject is blocked by an obstacle, and the like.

[0189] Since the timing suitable for imaging is a very short time, it is better to display information as soon as possible. Therefore, it is preferable to use the display device using the organic light-emitting element of the present embodiment. This is because the organic light-emitting element has a high response speed. The display device using the organic light-emitting element can be more suitably used than these devices, such as a liquid crystal display device, for which a display speed is required.

[0190] The imaging device 1100 has an optical unit (not shown). The optical unit has a plurality of lenses and forms an image on an imaging element housed in the housing 1104. The plurality of lenses can adjust the focus by adjusting their relative positions. This operation can also be performed automatically.

[0191] The display device according to this embodiment may have a color filter having red, green, and blue. The red, green, and blue of the color filter may be arranged in a delta array.

[0192] The display device according to this embodiment may be used for a display unit of an electronic device such as a mobile terminal. In that case, it may have both a display function and an operation function. Examples of the mobile terminal include mobile phones such as smartphones, tablets, head-mounted displays, and the like.

[0193] FIG. 3(b) is a schematic diagram showing an example of the 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 reaction unit of a touch panel method. The operation unit may be a biometric recognition unit that recognizes a fingerprint and performs unlocking or the like. An electronic device having a communication unit can also be called a communication device.

[0194] FIG. 4 is a schematic diagram showing an example of the display device according to this embodiment. FIG. 4(a) is a display device such as a TV monitor or a PC monitor. The display device 1300 has a frame 1301 and a display unit 1302. The light-emitting device according to this embodiment may be used for the display unit 1302. The display device 1300 has a base 1303 that supports the frame 1301 and the display unit 1302. The base 1303 is not limited to the form of FIG. 4(a). The lower side of the frame 1301 may also serve as the base. Further, the frame 1301 and the display unit 1302 may be curved so that the display surface of the display unit 1302 is curved. The radius of curvature may be 5000 mm or more and 6000 mm or less.

[0195] FIG. 4(b) is a schematic diagram showing another example of the display device according to the present embodiment. The display device 1310 in FIG. 4(b) is configured to be foldable 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 may include the 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 at the bending point. The first display unit 1311 and the second display unit 1312 may display different images, or may display one image together with the first and second display units.

[0196] FIG. 5(a) is a schematic diagram showing an example of the lighting device according to the present embodiment. The lighting device 1400 may include a housing 1401, a light source 1402, a circuit board 1403, an optical film 1404 that transmits the light emitted by the light source 1402, and a light diffusing portion 1405. The light source 1402 may include the organic light-emitting element according to the present embodiment. The optical filter may be a filter that improves the color rendering property of the light source. The light diffusing portion can effectively diffuse the light of the light source, such as lighting up, and deliver the light to a wide range. The optical filter and the light diffusing portion may be provided on the light-emitting side of the lighting. If necessary, a cover may be provided on the outermost side.

[0197] The lighting device is, for example, a device for lighting an indoor space. The lighting device may emit any color from white, day white, or other colors from blue to red. It may have a dimming circuit for dimming them or a color mixing circuit for mixing the emission colors. The lighting device may include the organic light-emitting element of the present embodiment and a power supply circuit connected thereto. The power supply circuit is a circuit that converts an AC voltage into a DC voltage. Also, white has a color temperature of 4200K and day white has a color temperature of 5000K. The lighting device may have a color filter.

[0198] In addition, the lighting device according to the present embodiment may have a heat radiating portion. The heat radiating portion releases the heat inside the device to the outside of the device, and examples thereof include metals with high specific heat and liquid silicon.

[0199] FIG. 5(b) is a schematic diagram of an automobile which is an example of the moving body according to the present embodiment. The automobile has a tail lamp which is an example of a lighting device. The automobile 1500 may have a form in which the tail lamp 1501 is lit when a braking operation or the like is performed.

[0200] The tail lamp 1501 may have an organic light-emitting element according to the present embodiment. The tail lamp 1501 may have a protective member for protecting the organic EL element. The protective member has a certain degree of strength and may be made of any material as long as it is transparent, but is preferably made of polycarbonate or the like. A phthalic acid derivative, an acrylonitrile derivative or the like may be mixed with the polycarbonate.

[0201] The automobile 1500 may have a vehicle 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 the present embodiment. In this case, constituent materials such as electrodes of the organic light-emitting element are made of transparent members.

[0202] The moving body according to the present embodiment may be a ship, an aircraft, a drone or the like. The moving body may have a fuselage and a lighting device provided on the fuselage. The lighting device may emit light for notifying the position of the fuselage. The lighting device has an organic light-emitting element according to the present embodiment.

[0203] With reference to FIG. 6, application examples of the display device of each of the above embodiments will be described. The display device can be applied to a system wearable as a wearable device such as smart glasses, an HMD, or smart contacts. The imaging display device used in such an application example has an imaging device capable of photoelectrically converting visible light and a display device capable of emitting visible light.

[0204] FIG. 6(a) 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 surface side of the lens 1601 of the glasses 1600. Also, a display device according to each of the above-described embodiments is provided on the back surface side of the lens 1601.

[0205] The glasses 1600 further include a control device 1603. The control device 1603 functions as a power source that supplies power to the imaging device 1602 and the display device according to each embodiment. Also, the control device 1603 controls the operations of the imaging device 1602 and the display device. An optical system for condensing light onto the imaging device 1602 is formed in the lens 1601.

[0206] FIG. 6(b) illustrates glasses 1610 (smart glasses) according to one application example. The glasses 1610 have a control device 1612, and an imaging device corresponding to the imaging device 1602 and a display device are mounted on the control device 1612. An optical system for the imaging device within the control device 1612 and for projecting light emitted from the display device is formed in the lens 1611, 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 controls the operations of the imaging device and the display device. The control device may have a gaze detection unit that detects the wearer's gaze. Infrared rays may be used for gaze detection. The infrared light emitting unit emits infrared light toward the eyeball of the user who is gazing at the display image. An imaging unit having a light receiving element detects the reflected light of the emitted infrared light from the eyeball, thereby obtaining an imaging image of the eyeball. By having a reduction means for reducing the light from the infrared light emitting unit to the display unit in a plan view, a reduction in image quality is reduced.

[0207] The user's gaze with respect to the display image is detected from the imaging image of the eyeball obtained by imaging infrared light. Any known method can be applied to gaze detection using the imaging image of the eyeball. As an example, a gaze detection method based on a Purkinje image by reflection of irradiation light on the cornea can be used.

[0208] More specifically, a line-of-sight detection process based on the pupil corneal reflex method is performed. Using the pupil corneal reflex method, a line-of-sight 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 line of sight.

[0209] The display device according to an 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 the user's line-of-sight information from the imaging device.

[0210] Specifically, the display device determines a first visual field region that the user gazes at and a second visual field region other than the first visual field region based on the line-of-sight information. The first visual field region and the second visual field region may be determined by the control device of the display device, or may be received from an external control device. In the display area of the display device, the display resolution of the first visual field region may be controlled to be higher than that of the second visual field region. That is, the resolution of the second visual field region may be made lower than that of the first visual field region.

[0211] Also, the display area has a first display area and a second display area different from the first display area, and based on the line-of-sight information, a region with a higher priority is determined from the first display area and the second display area. The first visual field region and the second visual field region may be determined by the control device of the display device, or may be received from an external control device. The resolution of the region with a higher priority may be controlled to be higher than that of the region other than the region with a higher priority. That is, the resolution of the region with a relatively lower priority may be made lower.

[0212] Note that AI may be used to determine the first visual field region or the region with a higher priority. AI may be a model configured to estimate the angle of the line of sight and the distance to the target at the tip of the line of sight from the image of the eyeball, using the image of the eyeball and the direction in which the eyeball in the image is actually looking as teacher data. The AI program may be possessed by the display device, the imaging device, or an external device. When an external device has it, it is transmitted to the display device via communication.

[0213] When performing display control based on visual recognition, it can be preferably applied to smart glasses that further include an imaging device for imaging the outside. The smart glasses can display the captured external information in real time.

[0214] FIG. 7 is a schematic diagram showing an example of the image forming apparatus according to the present embodiment. The image forming apparatus 40 is an electrophotographic image forming apparatus, and includes a photoreceptor 27, an exposure light source 28, a charging unit 30, a developing unit 31, a transferrer 32, a conveyance roller 33, and a fixing unit 35. Light 29 is emitted from the exposure light source 28, and an electrostatic latent image is formed on the surface of the photoreceptor 27. This exposure light source 28 has the organic light emitting element according to the present embodiment. The developing unit 31 has toner and the like. The charging unit 30 charges the photoreceptor 27. The transferrer 32 transfers the developed image onto a recording medium 34. The conveyance roller 33 conveys 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.

[0215] FIGS. 8(a) and 8(b) are views showing the exposure light source 28, and are schematic diagrams showing a state in which a plurality of light emitting portions 36 are arranged on a long substrate. Arrow 37 represents the column direction in which the organic light emitting elements are arranged. This column direction is the same as the direction of the axis around which the photoreceptor 27 rotates. This direction can also be called the major axis direction of the photoreceptor 27. FIG. 8(a) shows a form in which the light emitting portions 36 are arranged along the major axis direction of the photoreceptor 27. FIG. 8(b) shows a form different from FIG. 8(a), in which the light emitting portions 36 are alternately arranged in the column direction in each of the first column and the second column. The first column and the second column are arranged at different positions in the row direction. In the first column, a plurality of light emitting portions 36 are arranged at intervals. The second column has light emitting portions 36 at positions corresponding to the intervals between the light emitting portions 36 in the first column. That is, also in the row direction, a plurality of light emitting portions 36 are arranged at intervals. The arrangement in FIG. 8(b) can also be described as, for example, a state of being arranged in a grid pattern, a state of being arranged in a staggered grid, or a checkered pattern.

[0216] As described above, by using the device using the organic light-emitting element according to the present embodiment, it is possible to achieve a good image quality and a stable display even for a long-time display.

Example

[0217] Hereinafter, the present invention will be described by way of examples. However, the present invention is not limited thereto.

[0218] <Example 1 (Synthesis of Exemplary Compound A1)> According to the following scheme, the exemplary compound A1 was synthesized. The following scheme is a reaction scheme when compound E1 in which X is an oxygen atom is used as compound (a) in the above-described reaction scheme.

[0219]

Chemical formula

[0220] (1) Synthesis of Compound E3 The following reagents and solvents were charged into a 300 ml eggplant flask. Compound E1: 5.0 g (27.3 mmol) Compound E2: 7.7 g (27.3 mmol) Pd 2 (dba) 3 : 0.7 g (0.8 mmol) P(t-Bu) 3 : 0.6 g (2.7 mmol) NaO-t-Bu: 5.2 g (54.6 mmol) Toluene: 100 ml

[0221] Next, the reaction solution was heated and stirred at 100 ° C for 12 hours under a nitrogen stream. After heating and stirring, extraction was performed with toluene, and the organic layer was concentrated to dryness to obtain a solid. The obtained solid was purified by silica gel column chromatography (toluene: heptane mixture) to obtain 6.5 g of compound E3 (yield: 70%).

[0222] (2) Synthesis of Compound E5 A 300-ml eggplant flask was charged with the reagents and solvents shown below. Compound E3: 6.0 g (17.7 mmol) THF: 200 ml

[0223] Next, 11 ml of n-butyllithium (1.6 mol / L, hexane solution) was slowly added dropwise to the above reaction solution at -78°C under a nitrogen stream. After the addition, the reaction solution was stirred at -78°C for 1 hour. Then, 3.3 g (15.9 mmol) of Compound E4 dissolved in 30 ml of THF was slowly added dropwise to the reaction solution at -78°C. After the addition, the mixture was slowly returned to room temperature and stirred at room temperature for 2 hours. The reaction solution was quenched with an aqueous ammonium chloride solution and extracted with ethyl acetate. The organic layer was concentrated to dryness to obtain 2.3 g of Compound E5 (yield: 28%).

[0224] (3) Synthesis of Exemplary Compound A1 A 200-ml eggplant flask was charged with the reagents and solvents shown below. Compound E5: 2.0 g (4.3 mmol) Acetic acid: 100 ml Hydrochloric acid: 10 ml

[0225] Next, the above reaction solution was heated and stirred under reflux for 10 hours under a nitrogen stream. After completion of the reaction, water was added, and the precipitated solid was collected by filtration. The obtained solid was purified by silica gel column chromatography (chloroform:ethyl acetate mixture) to obtain 0.7 g of a yellow solid (Compound A1) (yield: 38%).

[0226] Mass spectrometry was performed on the obtained yellow solid (Compound A1) using MALDI-TOF-MS (Autoflex LRF manufactured by Bruker). Mass spectrometry confirmed that the target compound C-1 was successfully synthesized.

[0227] [MALDI-TOF-MS] Measured value: m / z = 450 Calculated value: C 32 H 19 NO 2 = 450

[0228] <Examples 2 to 17, Reference Examples 18 to 22 (Synthesis of Exemplary Compounds and Reference Compounds)> For the exemplary compounds shown in Examples 2 to 17 and the reference compounds shown in Reference Examples 18 to 22, each compound was synthesized in the same manner as in Example 1, except that starting material E1 in Example 1 was changed to starting material 1, starting material E2 was changed to starting material 2, and starting material E4 was changed to starting material 3. Also shown in Tables 5 to 7 are the measured values (m / z) of the mass spectrometry results measured in the same manner as in Example 1.

[0229]

Table 5

[0230]

Table 6

[0231]

Table 7

[0232] <Example 23> In this example, an organic EL device having a bottom emission type structure 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 was fabricated.

[0233] First, ITO was deposited on a glass substrate, and an ITO electrode (anode) was formed by performing a desired patterning process. At this time, the film thickness of the ITO electrode was set to 100 nm. The substrate on which the ITO electrode was thus formed was used as an ITO substrate in the following steps. Next, vacuum evaporation by resistance heating in a vacuum chamber was performed to continuously form an organic compound layer and an electrode layer shown in Table 7 below on the ITO substrate. At this time, the electrode area of the electrode (metal electrode layer, cathode) facing the ITO electrode was 3 mm 2 so as to be.

[0234]

Table 8

[0235] For the obtained device, the characteristics of the device were measured and evaluated. As the initial characteristics regarding light emission, green light emission with a maximum external quantum efficiency (E.Q.E.) of 11.2% was obtained. Specifically, the current-voltage characteristics were measured with a Keithley Instruments, Inc. picoammeter 4140B, and the emission luminance was measured with a Topcon BM7. Further, a continuous driving test was conducted at a current density of 50 mA / cm 2 and the time (LT95) until the luminance degradation rate reached 5% was measured, and it was 110 hours.

[0236] <Examples 24 to 27, Reference Example 28, Comparative Examples 1 to 2> In Example 23, an organic light-emitting device was fabricated in the same manner as in Example 23, except that the materials forming each layer were appropriately changed to the compounds shown in Table 9. For the layers not described in Table 8, the same configuration as in Example 23 was adopted. For the obtained device, the characteristics of the device were measured and evaluated in the same manner as in Example 23. The measurement results are shown in Table 9 together with the measurement results of Example 23.

[0237]

Table 9

[0238] As shown in Table 9, in Examples 23 to 27, organic light-emitting devices with a high maximum external quantum efficiency (E.Q.E.) and a long 5% degradation lifetime (LT95) were obtained. That is, in Examples 23 to 27, organic light-emitting devices with excellent luminous efficiency and excellent driving durability were obtained. In other words, it was found that each of the exemplified compounds shown in Table 9 is a compound excellent in luminous efficiency and driving durability when used in the light-emitting layer in an organic light-emitting device, and more specifically, when used as a light-emitting material in the light-emitting layer.

[0239] On the other hand, as shown in Table 9, in the organic light-emitting devices of Comparative Examples 1 and 2 using Comparative Compounds 1-a and 2-a, the following results were obtained: the maximum external quantum efficiency (E.Q.E.) was low, and the 5% degradation lifetime (LT95) was short.

[0240] Here, Comparative Examples 1 to 2 and Example 23 have the same configuration in all aspects except for the light-emitting material. In Comparative Examples 1 to 2, Comparative Compounds 1-a and 2-a are used as the light-emitting material, while in Example 23, Compound A1, which is one of the compounds of the present invention, is used as the light-emitting material. As described with reference to Table 1 and Table 2, Comparative Compound 1-a has a structure in which one of the aromatic rings having an amino group in the basic skeleton is not condensed with other aromatic rings, and the basic skeleton has a symmetric structure. Therefore, for the reasons described above, the organic light-emitting device of Comparative Example 1 had low luminous efficiency and low driving durability. Further, Comparative Compound 2-a has a structure having no chalcogen atom in the basic skeleton. Therefore, for the reasons described above, the organic light-emitting device of Comparative Example 2 had low luminous efficiency. On the other hand, as described with reference to Table 1 and Table 2, Compound A1 has a structure in which the aromatic ring having an amino group is condensed with another site bonded to the amino group via a chalcogen atom. Further, Compound A1 has an asymmetric basic skeleton. Furthermore, the HOMO is distributed in the chalcogen atom in the basic skeleton. Therefore, for the reasons described above, the organic light-emitting device of Example 23 had high luminous efficiency and high driving durability.

[0241] <Example 29> In this example, a bottom-emission type organic EL device having a structure 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 was fabricated.

[0242] First, ITO was deposited on a glass substrate, and an ITO electrode (anode) was formed by performing a desired patterning process. At this time, the film thickness of the ITO electrode was set to 100 nm. The substrate on which the ITO electrode was thus formed was used as an ITO substrate in the following steps. Next, vacuum evaporation by resistance heating in a vacuum chamber was performed to continuously deposit an organic compound layer and an electrode layer shown in Table 9 below on the ITO substrate. At this time, the electrode area of the electrode (metal electrode layer, cathode) facing the ITO electrode was 3 mm 2 to be this size.

[0243]

Table 10

[0244] Regarding the obtained device, the characteristics of the device were measured and evaluated. As the initial characteristics regarding light emission, green light emission with a maximum external quantum efficiency (E.Q.E.) of 10.3% was obtained. Specifically, the current-voltage characteristics of the measuring device were measured with a Keithley Instruments, Inc. microammeter 4140B, and the emission luminance was measured with a Topcon BM7. Furthermore, a continuous drive test was performed at a current density of 50 mA / cm 2 and the time (LT95) until the luminance degradation rate reached 5% was measured, and it was 170 hours.

[0245] <Examples 30 to 36, Reference Examples 37 to 39, Comparative Example 2> In Example 29, an organic light-emitting device was fabricated in the same manner as in Example 29, except that the compounds shown in Table 11 were appropriately changed. For the layers not described in Table 11, the same configuration as in Example 29 was adopted. Regarding the obtained device, the characteristics of the device were measured and evaluated in the same manner as in Example 29. The measurement results are shown in Table 11 together with the measurement results of Example 29.

[0246]

Table 11

[0247] As shown in Table 11, in Examples 29 to 36, organic light-emitting devices with high maximum external quantum efficiency (E.Q.E.) and long 5% degradation lifetime (LT95) were obtained. That is, in Examples 29 to 36, organic light-emitting devices with excellent luminous efficiency and excellent driving durability were obtained. In other words, it was found that each of the exemplified compounds shown in Table 11 is a compound excellent in luminous efficiency and driving durability when used in the light-emitting layer in an organic light-emitting device, and more specifically, when used as an assist material in the light-emitting layer.

[0248] On the other hand, as shown in Table 11, in the organic light-emitting devices of Comparative Examples 3 to 4 using Comparative Compounds 1-a and 2-a, the results showed that the maximum external quantum efficiency (E.Q.E.) was low and the 5% degradation lifetime (LT95) was short.

[0249] Here, Comparative Examples 3 to 4 and Example 29 have the same configuration in all aspects except for the assist material. In Comparative Examples 3 to 4, Comparative Compounds 1-a and 2-a are used as the assist material, and in Example 29, Compound A1, which is one of the compounds of the present invention, is used as the assist material. As described with reference to Table 1 and Table 2, Comparative Compound 1-a has a structure in which one of the aromatic rings having an amino group in the basic skeleton is not fused with other aromatic rings, and the basic skeleton has a symmetric structure. Therefore, for the reasons described above, the organic light-emitting device of Comparative Example 3 had low luminous efficiency and low driving durability. Further, Comparative Compound 2-a has a structure having no chalcogen atom in the basic skeleton. Therefore, for the reasons described above, the organic light-emitting device of Comparative Example 4 had low luminous efficiency. On the other hand, as described with reference to Table 1 and Table 2, Compound A1 has a structure in which the aromatic ring having an amino group is fused with another site bonded to the amino group via a chalcogen atom. Further, Compound A1 has an asymmetric basic skeleton. Furthermore, HOMO is distributed on the chalcogen atom in the basic skeleton. Therefore, for the reasons described above, the organic light-emitting device of Example 29 had high luminous efficiency and high driving durability.

Explanation of symbols

[0250] 1 Organic light-emitting device 11 Substrate 21 Anode 22 Organic compound layer 23 Cathode

Claims

1. An organic compound characterized by being represented by the following general formula [1-1]. 【Chemical 1】 (In the general formula [1-1], X is any one of an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom. R １ ~R19 are each independently selected from a hydrogen atom, a fluorine atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aromatic hydrocarbon group, a substituted or unsubstituted carbazole group, a trimethylsilyl group, and a triphenylsilyl group.) When the alkyl group, the aromatic hydrocarbon group, and the carbazole group have substituents, the substituents are each independently selected from an alkyl group, an aralkyl group, an aryl group, and a fluorine atom.)

2. The organic compound according to claim 1, wherein in the general formula [1-1], X is an oxygen atom.

3. The organic compound according to claim 1, wherein in the general formula [1-1], X is a sulfur atom.

4. The organic compound according to claim 1, wherein in the general formula [1-1], X is a selenium atom.

5. R １ R to R19 are each independently selected from a hydrogen atom, a fluorine atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 60 carbon atoms, a substituted or unsubstituted carbazole group, a trimethylsilyl group, and a triphenylsilyl group. The organic compound according to any one of claims 1 to 4, characterized in that.

6. Said R １９ is an organic compound according to any one of claims 1 to 5, characterized in that it is a hydrogen atom.

7. An anode and a cathode, In an organic light-emitting device having at least one organic compound layer disposed between the anode and the cathode, The organic light-emitting device, wherein the organic compound layer contains the organic compound according to any one of claims 1 to 6.

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

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

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

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

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

13. The organic light-emitting device according to any one of claims 8 to 12, wherein the light-emitting layer emits green light.

14. The organic light-emitting device according to any one of claims 8 to 13, wherein the light-emitting layer emits red light.

15. A display device having a plurality of pixels, wherein at least one of the plurality of pixels has the organic light-emitting device according to any one of claims 7 to 14 and a transistor connected to the organic light-emitting device.

16. A display device having a plurality of pixels, wherein at least one of the plurality of pixels has the organic light-emitting device according to any one of claims 7 to 14, a transistor connected to the organic light-emitting device, and a color filter.

17. An optical unit having a plurality of lenses, an image sensor that receives light that has passed through the optical unit, and a display unit that displays an image captured by the image sensor. The display unit has an organic light-emitting element according to any one of claims 7 to 14, and the photoelectric conversion device is characterized in that.

18. An electronic device, comprising: a display unit having an organic light-emitting element according to any one of claims 7 to 14; a housing provided with the display unit; and a communication unit provided in the housing and communicating with the outside.

19. An illumination device, comprising: a light source having an organic light-emitting element according to any one of claims 7 to 14; and a light diffusing unit or an optical filter that transmits light emitted by the light source.

20. A moving body, comprising: a lighting fixture having an organic light-emitting element according to any one of claims 7 to 14; and a body provided with the lighting fixture.

21. An exposure light source of an electrophotographic image forming apparatus, characterized by having an organic light-emitting element according to any one of claims 7 to 14.

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