A monoamine organic compound containing an imidazole heterocyclic group and a benzheterocyclic group, and an organic electroluminescent device comprising the same

Abstract

The present invention discloses a monoamine organic compound containing an imidazole heterocyclic group and a benzheterocyclic group, and an organic electroluminescent device comprising the same. The compound of the present invention is a monoamine compound containing both an imidazole heterocyclic group and a benzoxazole group or a benzothiazole group, having a suitable Eg energy level and thermal stability, a relatively low evaporation temperature and a decomposition temperature higher than the evaporation temperature, and a high extinction coefficient at a wavelength of 380 nm, capable of effectively absorbing high-energy external light sources in the ultraviolet region to minimize damage to the organic materials inside the organic light-emitting device. The compound of the present invention has a high refractive index in the visible light region. After being applied as a cover layer to an OLED device, it can effectively improve the light extraction efficiency of the OLED device and reduce the angular dependence, thereby improving the light-emitting efficiency of the device and optimizing the viewing angle performance.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and particularly to an organic compound of monoamine containing both imidazole heterocyclic group and benzoxazole group or benzothiazole group, and its use as a covering layer in an organic electroluminescent device. Background Art

[0002] Organic Light Emitting Diode (OLED), also known as an organic electroluminescent device, is a technology in which organic materials emit light through carrier injection and recombination under the action of an electric field. It can convert electrical energy into light energy through organic light emitting materials, including passive-driven OLED (PMOLED) and active-driven OLED (AMOLED). OLED is a new generation of display technology following Cathode Ray Tube (CRT) and Liquid Crystal Display (LCD), and is called a fantastic display technology. The essence of OLED is a thin film stacking device. Theoretically, when both the anode and the cathode are transparent electrodes, the light emitted from the light emitting layer can propagate from the anode to the outside of the device and also from the cathode to the outside of the device. Therefore, according to the path of light transmission, the device can be divided into a bottom-emitting device and a top-emitting device.

[0003] In the structure of a top-emitting organic electroluminescent device, since the metal cathode layer and the bottom metal reflective layer will form a resonant cavity (also called a microcavity), there are constructive interference and destructive interference. As the viewing angle changes, the distance between the metal cathode layer and the bottom metal reflective layer (i.e., the cavity length of the microcavity) changes accordingly, which will cause great differences in the brightness and color observed at different viewing angles, seriously affecting the product performance.

[0004] In such a light emitting element, when the light emitted from the light emitting layer is incident on other films, if it is incident at an angle above a certain angle, total reflection will occur at the interface between the light emitting layer and other films. Therefore, only a part of the emitted light can be utilized. In recent years, in order to improve the light extraction efficiency and improve the color shift, a light emitting element has been proposed in which a "covering layer" with a high refractive index is provided outside a semi-transparent electrode with a low refractive index.

[0005] In the formation of the cover layer, although the use of a high-precision metal mask has been proposed, there are the following problems for this metal mask: If the evaporation temperature of the cover layer is too high, due to the deformation caused by heat, the alignment accuracy deteriorates. If it is a high-precision mask, evaporation cannot be performed at the correct position. The evaporation temperatures of many inorganic substances are high, making them unsuitable for use with high-precision masks, and there is a possibility of damaging the light-emitting element itself. Furthermore, for film formation using the sputtering method, since the light-emitting element is damaged, a cover layer made of an inorganic substance cannot be used as a constituent material.

[0006] The following problems mainly exist when using a cover layer to improve the performance of OLED devices currently:

[0007] 1. When the evaporation temperature is too high, the CPL material decomposes severely during long-term evaporation.

[0008] 2. The light extraction efficiency is relatively low. After being applied to an OLED device, the light-emitting efficiency of the device increases only slightly.

[0009] 3. After being applied to an OLED device, the color deviation of the device is not improved significantly, the angular dependence of the emitted light is strong, and as the angle changes, the brightness decays and the emission color changes.

[0010] 4. The optimal evaporation film thickness range is relatively narrow. The CPL material can achieve the best device performance only when the film thickness is within a relatively narrow range, which requires high preparation processes, and the quality of the obtained device products varies greatly, with a low yield.

[0011] In order to continuously improve the performance of OLED devices, not only innovation in the OLED device structure and manufacturing process is required, but also continuous research and innovation in OLED optoelectronic functional materials to create higher-performance OLED functional materials. Therefore, finding a suitable material as a cover layer for OLED devices to solve the above problems is a long-term need in this field. Summary of the Invention

[0012] In view of the above problems existing in the prior art, the present application provides a monoamine organic compound containing an imidazole heterocyclic group and a benzheterocyclic group. The compound of the present invention has a high visible light refractive index and a high extinction coefficient @380 nm, a low evaporation temperature and a high decomposition temperature, and can be used as a cover layer to improve the light extraction efficiency and the angular dependence.

[0013] The present invention provides the following technical solution: A monoamine organic compound containing an imidazole heterocyclic group and a benzheterocyclic group, wherein the monoamine organic compound has a structure shown in the general formula (1):

[0014]

[0015] In general formula (1), X represents O or S;

[0016] In general formula (1), L, L 1 , L 2 each independently represents a single bond, a substituted or unsubstituted C 6 -C 50 arylene, a substituted or unsubstituted C 3 -C 50 heteroarylene; L, L 1 , L 2 may be the same or different;

[0017] In general formula (1), R 1 , R 2 , R 3 , R 4 each independently represents a hydrogen atom, a C 1 -C 10 alkyl or a C 6 -C 30 aryl;

[0018] R 1 and R 2 , R 2 and R 3 , R 3 and R 4 may also each independently be connected to each other to form a benzene ring;

[0019] In general formula (1), Z and Y each independently represent C-R; R represents a hydrogen atom or a phenyl group; Z and Y may be the same or different;

[0020] In general formula (1), Ar 1 represents a substituted or unsubstituted C 6 ~C 50 aryl, a substituted or unsubstituted C 3 ~C 50 heteroaryl;

[0021] The substituents of the said substituted C 6 ~C 50 arylene, the substituted C 3 ~C 50 substituents of the heteroarylene are each independently selected from one or more of a protium atom, a deuterium atom, a tritium atom, a halogen, a cyano group, a C 6 -C 30 aryl, a C 3 -C 30 heteroaryl containing one or more heteroatoms;

[0022] The heteroatoms in the said heteroaryl and heteroarylene are each independently selected from one or more of an oxygen atom, a sulfur atom or a nitrogen atom.

[0023] The present invention also provides an organic electroluminescent device, which includes:

[0024] a substrate layer;

[0025] a first electrode, which is on the substrate;

[0026] an organic light-emitting functional layer, which is on the first electrode;

[0027] a second electrode, which is on the organic light-emitting functional layer; and

[0028] a cover layer, which is on the second electrode;

[0029] The cover layer contains one or more of the monoamine organic compounds containing an imidazole heterocyclic group and a benzheterocyclic group.

[0030] The beneficial effects of the present invention are as follows:

[0031] The compound of general formula (1) of the present invention has excellent properties. Compared with CP-1, CP-2, CP-3, CP-4, and CP-5, it has a higher visible light refractive index and a suitable difference in refractive indices under blue light and red light. The refractive index of the monoamine organic compound containing an imidazole heterocyclic group and a benzheterocyclic group of the present invention ranges from 2.33 to 2.45 under blue light with a wavelength of 450 nm; ranges from 2.14 to 2.24 under green light with a wavelength of 525 nm; and ranges from 2.10 to 2.20 under red light with a wavelength of 620 nm. This is beneficial to improving the light extraction effect of the device and the viewing angle shift effect.

[0032] The compound of general formula (1) of the present invention also has a relatively low evaporation temperature of 300 - 360 °C, preferably 320 - 360 °C, more preferably 330 - 355 °C. This temperature is lower than the decomposition temperature to ensure that it will not decompose during the evaporation process, and it has high thermal stability.

[0033] The extinction coefficient of the compound of general formula (1) of the present invention ranges from 0.9 to 1.3 at a wavelength of 380 nm, which can effectively absorb high-energy external light sources in the ultraviolet region to minimize damage to the organic materials inside the organic electroluminescent device, thereby contributing to significantly improving the stability and service life of the organic electroluminescent device.

[0034] The compounds of the present invention are monoamine organic compounds containing both an imidazole heterocyclic group and a benzoxazole group or a benzothiazole group, having a relatively high glass transition temperature and molecular thermal stability, requiring a relatively low temperature for evaporation coating, and the decomposition temperature of the material being higher than the evaporation coating temperature of the material. Therefore, decomposition during evaporation coating is effectively avoided and it is suitable for long-term evaporation coating, while ensuring that crystallization does not occur after the material forms a film. In addition, it has a relatively high visible light refractive index in the visible light region. When a suitable Eg energy level is used as a cover layer in an OLED device, it can effectively improve the light extraction efficiency of the OLED device, reduce the power consumption of the device, improve the viewing angle dependence and the angle dependence of the emitted light, and expand the optimal evaporation coating thickness range on the premise of ensuring the best device performance.

[0035] The compounds of the present invention are suitable for long-term evaporation coating. After being applied to light-related devices, they can improve the light extraction efficiency of the devices and improve the angle dependence of the emitted light, and have a relatively large optimal evaporation coating thickness range on the premise of ensuring the best device performance, thereby being able to reduce the requirements for the manufacturing process and effectively improve the yield of flexible TFE encapsulated devices. Therefore, the compounds of the present invention are particularly suitable for use in light-related devices or components. In particular, the compounds of the present invention can be used as a cover layer in the devices or components to improve the light extraction efficiency and improve the angle dependence. In addition, using the compounds of the present invention as a cover layer to prepare devices or components can expand the optimal evaporation coating thickness range and improve the yield of flexible TFE encapsulated devices. Description of the Drawings

[0036] Figure 1 It is a schematic cross-sectional structure diagram of an application example (top-emitting organic electroluminescent device) of the compound of the present invention.

[0037] Among them, 100 is a substrate, 200 is a first electrode, 300 is an organic light-emitting functional layer, 400 is a second electrode, and 500 is a cover layer.

[0038] Figure 2 is Figure 1 A schematic cross-sectional structure diagram of the organic light-emitting functional layer 300 of the top-emitting organic electroluminescent device in []. Among them, 310 (HIL) is a hole injection layer, 320 (HTL) is a hole transport layer, 330 (EBL) is an electron blocking layer, 340 (EML) is a light-emitting layer, 350 (HBL) is a hole blocking layer, 360 (ETL) is an electron transport layer, and 370 (EIL) is an electron injection layer. Detailed Embodiments

[0039] Throughout the specification, unless explicitly described to the contrary, "comprising" any component shall be understood to implicitly include other elements, rather than excluding any other elements. In addition, it should be understood that throughout the specification, when an element such as a layer, film, region, or substrate is referred to as being "on" or "above" another element, it may be "directly on" the other element, or there may also be intermediate elements. Additionally, "on" or "above" means located above the target portion, and does not necessarily mean located above in the direction of gravity.

[0040] As used herein, "n@450nm" refers to the refractive index of the material relative to vacuum for blue light with a wavelength of 450 nm; "n@525nm" refers to the refractive index of the material relative to vacuum for green light with a wavelength of 525 nm; "n@620nm" refers to the refractive index of the material relative to vacuum for red light with a wavelength of 620 nm; "k@380nm" refers to the extinction coefficient of the material relative to vacuum for a wavelength of 380 nm. n@450nm - n@620nm refers to the difference between the refractive index of blue light at 450 nm and the refractive index of red light at 620 nm.

[0041] As used herein, C 6 -C 50 Aryl refers to a monovalent group including a carbocyclic aromatic system having 6 to 50 carbon atoms as ring-forming atoms. C 6 -C 50 Non-limiting examples of aryl may include phenyl, biphenyl, phenanthryl, terphenyl, naphthyl, phenanthryl, benzophenanthryl, etc. When C 6 -C 50 aryl includes two or more rings, these rings may be fused to each other.

[0042] As used herein, C 3 -C 50 Heteroaryl refers to a monovalent group including a carbocyclic aromatic system having at least one heteroatom selected from N, O, P, and S as ring-forming atoms and 3 to 50 carbon atoms. C 3 -C 50 Non-limiting examples of heteroaryl may include pyridyl, oxadiazolyl, triazinyl, pyrimidinyl, furyl, dibenzofuryl, dibenzothiophenyl, benzoxazolyl, bisbenzoxazolyl, carbazolyl, N-phenylcarbazolyl, quinolinyl, isoquinolinyl, naphthobenzofuryl, naphthofuryl, phenyl-substituted naphthofuryl, imidazopyridyl, imidazoquinolinyl, imidazoisoquinolinyl, etc. When C 3 -C 50 heteroaryl includes two or more rings, these rings may be fused to each other.

[0043] In this text, the C used 6 -C 30 Aryl refers to a monovalent group including a carbocyclic aromatic system having 6 to 30 carbon atoms as ring-forming atoms. The C used 6 -C 30 Aryl refers to a monovalent group including a carbocyclic aromatic system having 6 to 30 carbon atoms as ring-forming atoms. C 6 -C 30 Non-limiting examples of aryl may include phenyl, biphenyl, phenanthryl, terphenyl, naphthyl, phenanthryl, benzophenanthryl, etc.

[0044] In this text, the C used 3 -C 30 Heteroaryl refers to a monovalent group including a carbocyclic aromatic system having at least one heteroatom selected from N, O, P, and S as ring-forming atoms and 3 to 30 carbon atoms. C 3 -C 30 Non-limiting examples of heteroaryl may include pyridyl, oxadiazolyl, triazinyl, pyrimidinyl, furyl, dibenzofuranyl, dibenzothiophenyl, benzoxazolyl, bisbenzoxazolyl, carbazolyl, N-phenylcarbazolyl, quinolinyl, isoquinolinyl, naphthobenzofuranyl, naphthofuranyl, phenyl-substituted naphthofuranyl, imidazopyridyl, imidazoquinolinyl, imidazoisoquinolinyl, etc.

[0045] In this text, the C used 6 -C 30 Arylene refers to a divalent group including a carbocyclic aromatic system having 6 to 30 carbon atoms as ring-forming atoms, and non-limiting examples may include phenylene, biphenylene, phenanthrylene, terphenylenyl, naphthylene, phenanthrylene, benzophenanthrylene, etc.

[0046] In this text, the C used 3 -C 30 Heteroarylene refers to a divalent group including a carbocyclic aromatic system having at least one heteroatom selected from N, O, P, and S as ring-forming atoms and 3 to 30 carbon atoms, and non-limiting examples may include pyridylene, oxadiazolylene, triazinylene, pyrimidinylene, furylene, dibenzofuranylene, dibenzothiophenylene, benzoxazolylene, bisbenzoxazolylene, carbazolylene, N-phenylcarbazolylene, quinolinylene, isoquinolinylene, naphthobenzofuranylene, naphthofuranylene, phenyl-substituted naphthofuranylene, imidazopyridylene, imidazoquinolinylene, imidazoisoquinolinylene, etc.

[0047] C 1 -C 10An alkyl group refers to a monovalent group including an alkyl system having 1 to 10 carbon atoms. C 1 -C 10 Non-limiting examples of each alkyl group may include methyl, ethyl, propyl, butyl, isopropyl, tert-butyl, hexyl, etc.

[0048] The monoamine organic compound represented by the general formula (1)

[0049]

[0050] In the general formula (1), X represents O or S;

[0051] In the general formula (1), L, L 1 , L 2 each independently represents a single bond, a substituted or unsubstituted C 6 -C 50 arylene group, a substituted or unsubstituted C 3 -C 50 heteroarylene group; L, L 1 , L 2 may be the same or different;

[0052] In the general formula (1), R 1 , R 2 , R 3 , R 4 each independently represents a hydrogen atom, a C 1 -C 10 alkyl group or a C 6 -C 30 aryl group;

[0053] R 1 and R 2 , R 2 and R 3 , R 3 and R 4 may also each independently be connected to each other to form a benzene ring;

[0054] In the general formula (1), Z and Y each independently represent C-R; R represents a hydrogen atom or a phenyl group; Z and Y may be the same or different;

[0055] In the general formula (1), Ar 1 represents a substituted or unsubstituted C 6 ~C 50 aryl group, a substituted or unsubstituted C 3 ~C 50 heteroaryl group;

[0056] The substituted C 6 ~C 50 arylene group, the substituted C 3 ~C 50The substituents of the heteroarylene are each independently selected from a hydrogen atom, a deuterium atom, a tritium atom, a halogen, a cyano group, a C 6 -C 30 aryl, a C containing one or more heteroatoms 3 -C 30 heteroarylene, or one or more of the above;

[0057] In the heteroarylene and heteroarylene moiety, the heteroatoms are each independently selected from one or more of an oxygen atom, a sulfur atom or a nitrogen atom.

[0058] In a preferred embodiment, the monoamine organic compound has a structure represented by the general formula (2):

[0059]

[0060] In the general formula (2), X represents O or S;

[0061] In the general formula (2), m = 1 or 2;

[0062] In the general formula (2), L and L 1 each independently represent a single bond, a substituted or unsubstituted C 6 -C 50 arylene, a substituted or unsubstituted C 3 -C 50 heteroarylene; L and L 1 may be the same or different;

[0063] In the general formula (2), R 1 , R 2 , R 3 , R 4 each independently represent a hydrogen atom, a C 1 -C 10 alkyl or a C 6 -C 30 aryl;

[0064] R 1 and R 2 , R 2 and R 3 , R 3 and R 4 may also each independently be connected to each other to form a benzene ring;

[0065] In the general formula (2), Z and Y each independently represent C-R; R represents a hydrogen atom or a phenyl group;

[0066] In the general formula (2), Ar 1 represents a substituted or unsubstituted C 6 ~C 50 aryl, a substituted or unsubstituted C 3 ~C 50 heteroaryl;

[0067] The substituted C 6 -C 50 -aryl, substituted C 3 -C 50 -heteroaryl substituents are each independently selected from a hydrogen atom, a deuterium atom, a tritium atom, a halogen, a cyano group, C 6 -C 30 -aryl, C containing one or more heteroatoms 3 -C 30 -heteroaryl;

[0068] The heteroatoms in the heteroaryl and heteroarylene are each independently selected from one or more of an oxygen atom, a sulfur atom, or a nitrogen atom.

[0069] Preferably, the structure of the monoamine organic compound is as shown in the general formula (1-2);

[0070]

[0071] The definitions of X, L, L 1 , Ar 1 , R, and m are the same as defined in the general formula (2).

[0072] Preferably, the structure of the monoamine organic compound is as shown in the general formula (1-3);

[0073]

[0074] The R 1 , R 2 , R 3 , R 4 , X, L, L 1 , Ar 1 , R, and m are the same as defined in the general formula (2).

[0075] Preferably, the Ar 1Each independently represents a substituted or unsubstituted phenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted biphenyl, substituted or unsubstituted terphenyl, substituted or unsubstituted anthryl, substituted or unsubstituted phenanthryl, substituted or unsubstituted benzophenanthryl, substituted or unsubstituted pyridyl, substituted or unsubstituted carbazolyl, substituted or unsubstituted furyl, substituted or unsubstituted naphthobenzofuryl, substituted or unsubstituted thienyl, substituted or unsubstituted pyrimidinyl, substituted or unsubstituted pyrazinyl, substituted or unsubstituted pyridazinyl, substituted or unsubstituted dibenzofuryl, substituted or unsubstituted N-phenylcarbazolyl, substituted or unsubstituted N-biphenylcarbazolyl, substituted or unsubstituted N-naphthylcarbazolyl, substituted or unsubstituted N-dibenzofurylcarbazolyl, substituted or unsubstituted quinolinyl, substituted or unsubstituted isoquinolinyl, substituted or unsubstituted quinazolinyl, substituted or unsubstituted quinoxalinyl, substituted or unsubstituted cinnolinyl, substituted or unsubstituted dibenzothienyl, substituted or unsubstituted carbazolinyl, substituted or unsubstituted naphthyridinyl, substituted or unsubstituted benzoxazolyl, substituted or unsubstituted benzothiazolyl, substituted or unsubstituted naphthofuryl, substituted or unsubstituted naphthothienyl, substituted or unsubstituted imidazo[1,2-a]pyridinyl, substituted or unsubstituted imidazo[2,1-a]isoquinolinyl, substituted or unsubstituted imidazo[1,2-a]quinolinyl, substituted or unsubstituted imidazo[1,2-b]isoquinolinyl;

[0076] Said R 1 , R 2 , R 3 , R 4 Each independently represents a hydrogen atom, methyl, ethyl, propyl, phenyl or naphthyl; said R 1 and R 2 , R 2 and R 3 , R 3 and R 4 can also be independently connected to each other to form a benzene ring;

[0077] Said L, L 1 , L 2 Each independently represents a single bond, substituted or unsubstituted phenylene, substituted or unsubstituted biphenylene, substituted or unsubstituted naphthylene, substituted or unsubstituted pyridylene, substituted or unsubstituted phenanthrylene; L, L 1 , L 2 can be the same or different;

[0078] The substituents of the "substituted or unsubstituted" group are each independently selected from one or more of phenyl, naphthyl, biphenyl, terphenyl, pyridyl, pyrimidinyl, pyrazinyl, pyridazinyl, quinolinyl, isoquinolinyl, benzoxazolyl, benzothiazolyl, benzimidazolyl, quinoxalinyl, quinazolinyl, cinnolinyl, naphthyridinyl, fluorenyl, dibenzofuranyl, N-phenylcarbazolyl, dibenzothiophenyl, naphthofuranyl, naphthothiophenyl, imidazo[1,2-a]pyridyl, imidazo[2,1-a]isoquinolinyl, imidazo[1,2-a]quinolinyl, imidazo[1,2-b]isoquinolinyl.

[0079] Preferably, the structure of the monoamine organic compound is represented by the general formula (I-1) or (I-2);

[0080]

[0081] In the general formulas (I-1) and (I-2), the definitions of X, L, L 1 , Ar 1 , R, and m are the same as those defined in the general formula (2).

[0082] Preferably, the structure of the monoamine organic compound is represented by the general formula (II-1), general formula (II-2), general formula (II-3), general formula (II-4), general formula (II-5), or general formula (II-6);

[0083]

[0084] In the general formulas (II-1), (II-2), (II-3), (II-4), (II-5), and (II-6), the definitions of X, L, L 1 , Ar 1 , R, and m are the same as those defined in the general formula (2).

[0085] Preferably, the structure of the monoamine organic compound is represented by the general formula (III-1), (III-2), (III-3), (III-4), or (III-5);

[0086]

[0087] In the general formulas (III-1), (III-2), (III-3), (III-4), and (III-5), the definitions of R 1 , R 2 , R 3 , R 4 , X, L, L 1 , Z, Y, and m are the same as those defined in the general formula (2);

[0088] In general formula (III-1), the X 1 represents O or S;

[0089] In general formula (III-3), the X 2 represents O, S or N-R 0 ; the R 0 represents phenyl, biphenyl, pyridyl, naphthyl or dibenzofuranyl; the R 5 , R 6 , R 7 , R 8 each independently represents a hydrogen atom, phenyl or naphthyl; the R 5 and R 6 , R 6 and R 7 , R 7 and R 8 can also be independently connected to each other to form a benzene ring.

[0090] Preferably, the structure of the monoamine organic compound is as shown in general formulas (IV-1), (IV-2), (IV-3), (IV-4), (IV-5), (IV-6), (IV-7) or (IV-8);

[0091]

[0092]

[0093] In general formulas (IV-1), (IV-2), (IV-3), (IV-4), (IV-5) and (IV-6), the X, X 1 each occurrence represents -O- or -S- the same or differently; the X, X 1 can be the same or different;

[0094] In general formulas (IV-1), (IV-2), (IV-3), (IV-4), (IV-5), (IV-6), (IV-7) and (IV-8), the L, L 1 , R, m are defined as in general formula (2).

[0095] Preferably, the specific structural formula of the monoamine organic compound is any one of the following structures:

[0096]

[0097]

[0098]

[0099]

[0100]

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107]

[0108] Preferably, the extinction coefficient of the monoamine organic compound ranges from 0.9 to 1.3 at a wavelength of 380 nm; the refractive index ranges from 2.33 to 2.45, preferably from 2.38 to 2.45, under blue light at a wavelength of 450 nm; the refractive index ranges from 2.14 to 2.24 under green light at a wavelength of 525 nm; and the refractive index ranges from 2.10 to 2.20, preferably from 2.12 to 2.17, under red light at a wavelength of 620 nm.

[0109] Preferably, the difference in refractive index of the monoamine organic compound between blue light and red light is 0.21 - 0.26.

[0110] Preferably, the evaporation temperature of the monoamine organic compound is lower than the decomposition temperature, and the evaporation temperature is 300 - 360 °C, preferably 320 - 360 °C, more preferably 330 - 355 °C.

[0111] Organic electroluminescent device

[0112] The compound of the present invention is particularly suitable for evaporation and for improving light extraction efficiency, and can improve the stability of the production process, increase the optimal evaporation film thickness range, and avoid the phenomenon of black spots in the device, etc. The obtained device or component has a high yield and a high visible light extraction efficiency. Therefore, an object of the present invention is to provide an organic electroluminescent device, which includes: a substrate layer; a first electrode on the substrate; an organic light-emitting functional layer on the first electrode; a second electrode on the organic light-emitting functional layer; and a covering layer on the second electrode; wherein the covering layer includes one or more of the monoamine organic compounds containing an imidazole heterocyclic group and a benzheterocyclic group represented by the general formula (1).

[0113] In one embodiment of the present invention, the capping layer in the organic electroluminescent (OLED) device comprises one or more of the compounds of the general formula (1) above or consists of one or more compounds of the general formula (1) above; wherein the capping layer is 10 - 1000 nm, preferably 40 - 140 nm, more preferably 50 - 90 nm, still more preferably 60 - 80 nm, and most preferably 65 - 75 nm.

[0114] Preferably, the device comprises one or more combinations of blue, green or red organic light-emitting material layers; different organic light-emitting material layers are stacked horizontally or vertically.

[0115] In a preferred embodiment of the present invention, an OLED is provided, which comprises a substrate, an anode, a cathode, an organic light-emitting functional layer and a capping layer, wherein the organic light-emitting functional layer may include a light-emitting layer, a hole transport layer, a hole injection layer, an electron blocking layer, an electron transport layer, an electron injection layer, etc., or may only include a light-emitting layer and one or more other layers, and wherein the capping layer consists of one or more of the compounds of the general formula (1) above or includes one or more compounds of the general formula (1). Optionally, there are a protective layer and a packaging layer above the capping layer.

[0116] As Figure 1 shown, for the substrate 100, any substrate used in a typical organic light-emitting device can be selected. It can be a glass or transparent plastic substrate, or a substrate of an opaque material such as silicon or stainless steel, or a flexible PI film. Different substrates have different mechanical strengths, thermal stabilities, transparencies, surface smoothness, water resistances, and are used in different directions according to the properties of the substrates.

[0117] A first electrode 200 is formed on the substrate 100. The first electrode 200 can be a cathode or an anode. Here, the first electrode 200 can be merely a reflective electrode such as a reflective film formed of silver (Ag), magnesium (Mg), aluminum (Al), gold (Au), nickel (Ni), chromium (Cr)) or an alloy thereof, or can be an electrode formed by combining a reflective film and a transparent or semi-transparent electrode, for example, a transparent or semi-transparent electrode layer having a high work function and formed on the reflective film. The transparent or semi-transparent electrode layer can be formed of indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), aluminum zinc oxide (AZO), indium gallium oxide (IGO), indium oxide (In 2 O 3 ) or tin oxide (SnO 2 ); or can be formed by combining a metal and an oxide, for example, formed of ITO / Ag / ITO, IGO / Al / IGO or AZO / Ag / AZO.

[0118] The first electrode 200 can be formed by methods such as sputtering, ion plating, vacuum evaporation, spin coating, electron beam evaporation, or chemical vapor deposition (CVD), and is preferably formed by sputtering.

[0119] The thickness of the first electrode layer 200 depends on the material used and is generally 5 nm - 1 μm, preferably 10 nm - 1 μm, more preferably 10 nm - 500 nm, particularly preferably 10 nm - 300 nm, and most preferably 10 nm - 200 nm.

[0120] As Figure 2 As shown, the organic light-emitting functional layer 300 may include a light-emitting layer 340 (EML). If the first electrode 200 is an anode, a hole transport region may be formed between the EML and the first electrode 200, and an electron transport region may be formed between the EML and the second electrode layer 400; if the first electrode 200 is a cathode, an electron transport region may be formed between the EML and the first electrode 200, and a hole transport region may be formed between the EML and the second electrode layer 400. The hole transport region may include at least one of a hole injection layer 310 (HIL), a hole transport layer 320 (HTL), and an electron blocking layer 330 (EBL). The electron transport region may include at least one of a hole blocking layer 350 (HBL), an electron transport layer 360 (ETL), and an electron injection layer 370 (EIL). Therefore, the organic light-emitting functional layer 300 includes a light-emitting layer and a combination of at least two layers among a hole injection layer, a hole transport layer, an electron blocking layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

[0121] The thickness of the organic light-emitting functional layer 300 is 50 nm - 1000 nm.

[0122] As the materials for the hole injection layer, hole transport layer, and electron blocking layer (HIL 310, HTL 320, EBL 330), any material can be selected from known related materials for OLED devices for use.

[0123] At least one layer of HIL310 and HTL320 may further include a charge generation material for improving conductivity. The charge generation material may be a p-dopant. Non-limiting compounds of p-dopants such as: quinone derivatives, such as tetracyanoquinodimethane (TCNQ) and 2,3,5,6-tetrafluoro-tetracyano-1,4-benzoquinodimethane (F4-TCNQ); or hexaazatriphenylene derivatives, such as 2,3,6,7,10,11-hexacyano-1,4,5,8,9,12-hexaazatriphenylene (HAT-CN); or cyclopropane derivatives, such as 4,4',4″-((1E,1'E,1″E)-cyclopropane-1,2,3-trimethylenetris(cyanomethylene)) tris(2,3,5,6-tetrafluorobenzyl); or metal oxides, such as tungsten oxide and molybdenum oxide, but not limited thereto.

[0124] It is required that the triplet (T1) energy level of the material in EBL330 is higher than the T1 energy level of the host material in the light-emitting layer 340, which can play a role in blocking the energy loss of the light-emitting layer material; the HOMO energy level of the EBL330 material is between the HOMO energy level of the HTL320 material and the HOMO energy level of the host material in the light-emitting layer 340, which is beneficial to the injection of holes from the positive electrode into the light-emitting layer. At the same time, it is required that the EBL330 material has a high hole mobility, which is beneficial to hole transport and reduces the device application power; the LUMO energy level of the EBL330 material is higher than the LUMO energy level of the host material in the light-emitting layer 340, playing an electron blocking role, that is, it is required that the EBL330 material has a wide bandgap (Eg). The EBL330 material meeting the above conditions can be triarylamine derivatives, fluorene derivatives, spirofluorene derivatives, dibenzofuran derivatives, carbazole derivatives, etc. Among them, triarylamine derivatives are preferred, such as N4,N4-bis([1,1'-biphenyl]-4-yl)-N4'-phenyl N4'-[1,1':4',1″-terphenyl]-4-yl-[1,1'-biphenyl]-4,4'-diamine; spirofluorene derivatives, such as N-([1,1'-diphenyl]-4-yl)-N-(9,9-dimethyl-9H-fluoren-2-yl)-9,9'-spirobifluorene-2-amine; dibenzofuran derivatives, such as N,N-bis([1,1'-biphenyl]-4-yl)-3'-(dibenz[b,d]furan-4-yl)-[1,1'-biphenyl]-4-amine, but not limited thereto.

[0125] In order to obtain a high-efficiency OLED device, the light-emitting layer 340 can use the same doping material or multiple doping materials. The doping materials can be pure fluorescent materials, thermally activated delayed fluorescence (TADF) materials or phosphorescent materials, or combinations of different fluorescent materials, TADF materials and phosphorescent materials. The light-emitting layer 340 can be a single light-emitting layer material or a composite light-emitting layer material stacked horizontally or vertically.

[0126] The host material constituting the light-emitting layer of the above-mentioned OLED light-emitting body needs to have not only bipolar charge transfer characteristics, but also an appropriate energy level, so that the excitation energy generated by the recombination of electrons and holes can be effectively transferred to the guest light-emitting material, that is, the doping material. Such materials include, for example, distyryl arylene derivatives, isocyanate derivatives, carbazole derivatives, triarylamine derivatives, anthracene derivatives, pyrene derivatives, triazine derivatives, xanthone derivatives, triphenylene derivatives, triazine derivatives, hexaphenylene derivatives or bis(2-methyl-8-quinoline)(p-phenylphenol)aluminum (BAlq).

[0127] The materials constituting the hole blocking layer 350 and the electron transport layer 360 of the OLED device can be any materials selected from materials used for OLEDs that have electron transport properties. Examples of such materials include oxadiazole derivatives such as 1,3-bis[5'-(p-tert-butylphenyl)-1,3,4-oxadiazole-2'-yl]benzene, 2-(4-biphenyl)-5-(4-tert-butylphenyl)-1,3,4-oxadiazole, triazole derivatives such as 3-(4'-tert-butylphenyl)-4-phenyl-5-(4″-biphenyl)-1,2,4-triazole, triazine derivatives, quinoline derivatives, quinoxaline derivatives, diphenylquinone derivatives, nitro-substituted quinone derivatives, thiopyran dioxide derivatives, anthraquinone dimethane derivatives, thiopyran dioxide derivatives, heterocyclic tetracarboxylic anhydrides such as naphthyl perylene, carbodiimides, quinone derivatives, anthraquinone dimethane derivatives, anthrone derivatives, distyrylpyrazine derivatives, silcyclopentadiene derivatives, phenanthroline derivatives or imidazopyridine derivatives.

[0128] A second electrode 400 is formed on the organic light-emitting functional layer 300. The second electrode layer can be a cathode or an anode, and can be a transparent electrode or a semi-transparent electrode. The second electrode 400 can be made of a thin film with a low work function made of lithium, calcium, lithium fluoride / calcium, lithium fluoride / aluminum, aluminum, silver, magnesium or an alloy thereof. Further, the second electrode layer 400 can be made of an alloy including silver and at least one metal, wherein the at least one metal includes aluminum, platinum, ytterbium, chromium or magnesium. Moreover, the weight ratio of Ag in the alloy can be the same as that of other metals or greater than or less than the weight of other metals. For example: the second electrode layer 400 can be formed of an Ag-Mg alloy, wherein the mass ratio of Ag to Mg can be 90:10 to 10:90. Alternatively, the second electrode layer 400 can be formed of an alloy including at least one metal such as silver, gold, platinum, copper, nickel or tungsten and at least one metal such as ytterbium, indium, magnesium or chromium. These metal films can form transparent or semi-transparent electrodes by adjusting the thickness of the film. Therefore, the light generated by the organic light emitting functional layer 300 can be emitted through the second electrode layer 400. In addition, the thickness of the second electrode layer 400 can be 5-20 nm.

[0129] A covering layer 500 is formed on the second electrode layer 400, and the material used for the covering layer 500 is composed of one or more of the compounds of the above general formula (1) or includes one or more compounds of the general formula (1).

[0130] The covering layer of the present invention is 10 - 1000 nm, preferably 40 - 140 nm, more preferably 50 - 90 nm, still more preferably 60 - 80 nm, and most preferably 65 - 75 nm.

[0131] Reference Figure 1 The organic electroluminescent device of the present invention includes a substrate layer 100, a first electrode layer 200, an organic light-emitting functional layer 300, a second electrode layer 400, and a covering layer 500.

[0132] A barrier layer (which can be composed of inorganic materials or / and organic materials and is used to prevent foreign substances from penetrating the substrate and the device) and a wiring layer (which can include a driving TFT, a capacitor, a wire, and low-temperature polysilicon LTPS) can be formed on the substrate layer by a known method.

[0133] In a specific embodiment, the first electrode 200 can be a reflective electrode and the second electrode 400 is a transparent or semi-transparent electrode. Therefore, the light generated by the organic light-emitting functional layer 300 can be directly emitted by the second electrode 400, or can be reflected by the first electrode 200 towards the second electrode 400 and then emitted. The first electrode 200 can be prepared by, for example, evaporation or sputtering. The second electrode 400 can be prepared by, for example, vacuum evaporation.

[0134] The organic light-emitting functional layer 300 can include a light-emitting layer 340 (EML), and a hole transport region can be formed between the EML and the first electrode 200, and an electron transport region can be formed between the EML and the second electrode layer 400. The hole transport region can include at least one of a hole injection layer 310 (HIL), a hole transport layer 320 (HTL), and an electron blocking layer 330 (EBL). The electron transport region can include at least one of a hole blocking layer 350 (HBL), an electron transport layer 360 (ETL), and an electron injection layer 370 (EIL).

[0135] The organic light-emitting functional layer 300 can be composed of small molecule organic materials or polymer materials, and the organic light-emitting functional layer 300 can be prepared by various methods, such as vacuum evaporation, solution spin coating, screen printing, and inkjet printing.

[0136] The covering layer 500 can be composed of the organic compound based on the heteroarylamine structure, and the covering layer 500 can be prepared by a variety of methods, such as vacuum evaporation, solution spin coating, screen printing, inkjet printing.

[0137] In addition, it can be prepared by referring to Figure 1 、 Figure 2 the structure of the top-emitting organic electroluminescent device to prepare a full-color top-emitting organic electroluminescent device. That is, the organic light-emitting device according to these embodiments can be configured in a variety of structures, such as a monochromatic light-emitting device, a top-emitting organic electroluminescent device for multi-color light or white light.

[0138] A protective layer is provided on the covering layer 500. The protective layer contains lithium fluoride (LiF). The thickness of the protective layer depends on the material used, usually 20 - 400 nm, preferably 30 - 200 nm and more preferably 40 - 100 nm.

[0139] An encapsulation layer is provided on the protective layer. The encapsulation layer is a protective structure for preventing external substances such as moisture and oxygen from entering the organic layer of the organic electroluminescent device, and is a multi-layer thin film covering the entire surface of the organic layer, the covering layer, and the protective layer. It includes a first encapsulation layer on the protective layer, a second encapsulation layer on the first encapsulation layer, and a third encapsulation layer on the second encapsulation layer; the first encapsulation layer is an inorganic layer; the second encapsulation layer is an organic layer; the third encapsulation layer is an inorganic layer; the inorganic layer contains at least one selected from the group consisting of Al 2 O 3 、SiO x N y 、TiO 2 、SiO x and SiN x wherein x and y are the same or different, and x and y are independently greater than 0 and less than 10, preferably greater than 0 and less than 5, and most preferably greater than 0 and less than 3. The inorganic layer is prepared by chemical vapor deposition (CVD).

[0140] As the organic material for the encapsulation layer of the organic electroluminescent device of the present invention, the organic materials for the encapsulation layer of organic electroluminescent devices known in the prior art can be used. In a preferred embodiment of the present invention, the organic material used for the encapsulation layer is polydimethylsiloxane (PDMS), polymethyl methacrylate (PMMA), polystyrene (PS), a polymer derivative having a phenol group, an acryl-based polymer, an imide-based polymer, an arylether-based polymer, an amide-based polymer, a fluorine-based polymer, a p-xylene-based polymer, a vinyl alcohol-based polymer, or a mixture thereof.

[0141] The thickness of the organic material for the encapsulation layer is sufficient to cover the encapsulation inorganic layer, and the organic material for the encapsulation layer is cured into a polymer by UV curing.

[0142] According to the present invention, the organic electroluminescent device is preferably a top-emitting organic electroluminescent device, which includes, after preparing the anode, cathode, and organic light-emitting functional layer, evaporating a material containing the compound of the general formula (1) of the present invention as a cover layer on the light-emitting side to improve the light extraction efficiency and the viewing angle dependence problem.

[0143] The viewing angle dependence problem mentioned herein refers to the gradual change in the emission color when observing the device at different angles. In this article, improving the viewing angle dependence and reducing the angle dependence are reflected in that as the viewing angle changes, the change trend of the emission color is significantly reduced, and ideally the emission color does not change. It can be measured by the parameter JNCD (JUST NOTICEABLE COLOR DIFFERENCE). JNCD is the obvious color difference perceptible to the human eye. The smaller the JNCD value, the more obvious the effect of improving the viewing angle dependence.

[0144] In addition, the OLED device of the present invention can be used in OLED lighting and display devices.

[0145] Preferably, the OLED device prepared by the present invention is used in fields such as smart phones, tablet computers, etc., the field of smart wearable devices, large-size application fields such as televisions, the VR and microdisplay fields, and automotive center control screens or automotive tail lights.

[0146] Examples

[0147] The present invention will be specifically described below with reference to the accompanying drawings and examples.

[0148] I. Synthesis of Intermediate A

[0149] Synthesis of Intermediate A-1:

[0150]

[0151] Under nitrogen protection, in a 500 ml round-bottom flask, successively add raw material C1 (25 mmol), raw material D1 (62.5 mmol), 1,2-dichloroethane (150 mL), CuI (3.8 mmol), tBuOK (50 mmol), tert-butyl nitrite (50 mmol), di-tert-butyl peroxide (75 mmol). After purging the air three times by passing nitrogen for 30 min, heat the mixture to 80 °C under nitrogen protection and react for 10 h. Take a TLC test of the reaction solution and find that raw material C1 has completely reacted. After the reaction is completed, naturally cool the reaction system to room temperature, quench the reaction with saturated aqueous sodium bicarbonate solution (50 mL), rotary evaporate to remove the solvent, dissolve the residue in ethyl acetate (150 mL), wash with 100 ml of water, pour it into a separatory funnel, shake and then let it stand for liquid separation. After liquid separation, extract the aqueous phase with ethyl acetate (50 ml * 3). Combine the organic phases, add anhydrous magnesium sulfate for drying, filter, rotary evaporate the filtrate to remove ethyl acetate to obtain the crude product, and purify the crude product by silica gel column chromatography to obtain Intermediate A1. LC-MS: Measured value: 323.30 ([M + H]+); exact mass: 322.01.

[0152] The synthesis of Intermediate A-1 was all prepared with reference to the synthesis scheme in the literature of J. Org. Chem. 2018, 83, 1056 - 1064.

[0153] Intermediate A was prepared by a method similar to that of Intermediate A1, and the raw materials C and D used are shown in Table 1;

[0154] Table 1

[0155]

[0156] Mass spectrometry data of Intermediate A3: LC-MS: Measured value: 323.26 ([M + H]+); exact mass: 322.01.

[0157] Mass spectrometry data of Intermediate A4: LC-MS: Measured value: 323.05 ([M + H]+); exact mass: 322.01.

[0158] II. Synthesis of Intermediate B:

[0159] The reactions involved in the preparation of Intermediate B1, Intermediate B2, Intermediate B3, Intermediate B6, Intermediate B7, Intermediate B8, Intermediate B9, and Intermediate B10 are conventional carbon-nitrogen coupling reactions and can be prepared with reference to the existing technology.

[0160] Synthesis of Intermediate B-4:

[0161]

[0162] Under nitrogen protection, in a 500 ml round-bottom flask, successively add raw material E1 (10 mmol), raw material F1 (12 mmol), and stir and mix with 200 ml of toluene. After purging with nitrogen for 30 min to displace air three times, add Pd 2 (dba) 3 (0.05 mmol), P(t-Bu) 3 (0.15 mmol), sodium tert-butoxide (30 mmol), and heat under reflux for 24 h under nitrogen protection. Take the reaction solution for TLC detection and find that raw material E1 has completely reacted. After the reaction is completed, naturally cool the reaction system to room temperature, rotary evaporate to remove the solvent, dissolve the residue in dichloromethane (150 ml), wash with water (100 ml), pour it into a separatory funnel, shake and let it stand for layering. After liquid separation, extract the aqueous phase with dichloromethane (50 ml * 3). Combine the organic phases, add anhydrous magnesium sulfate for drying, filter, rotary evaporate the filtrate to remove dichloromethane to obtain the crude product, and purify the crude product by silica gel chromatography column to obtain Intermediate B4. LC-MS: Measured value: 414.33 ([M + H]+); exact mass: 413.15.

[0163] Intermediate B5 is prepared by a synthesis method similar to that of Intermediate B4, and the raw materials E and F used are shown in Table 2;

[0164] Table 2

[0165]

[0166] III. Preparation of the Compounds of the Present Invention

[0167] Synthesis Example 1: Synthesis of Compound 1:

[0168]

[0169] Under nitrogen protection, in a 500 ml round-bottom flask, successively add Intermediate A1 (10 mmol), Intermediate B1 (12 mmol), and stir and mix with 200 ml of toluene. After purging with nitrogen for 30 min to displace air, add Pd 2 (dba) 3 (0.05 mmol), P(t-Bu) 3(0.15 mmol), sodium tert-butoxide (30 mmol), and heated under reflux for 24 h under nitrogen protection. The reaction solution was taken for TLC detection and it was found that the intermediate A1 had completely reacted. After the reaction was completed, the reaction system was naturally cooled to room temperature, the solvent was removed by rotary evaporation, the residue was dissolved in ethyl acetate (150 ml), washed with water (100 ml), poured into a separatory funnel, shaken, and allowed to stand for layer separation. After liquid separation, the aqueous phase was extracted with ethyl acetate (50 ml * 3). The combined organic phases were dried over anhydrous magnesium sulfate, filtered, and the filtrate was concentrated by rotary evaporation to remove ethyl acetate to obtain the crude product. The crude product was purified by silica gel column chromatography to obtain Compound 1. Elemental analysis of the structure (molecular formula C 43 H 27 N 5 O 2 ) Theoretical values: C, 79.98; H, 4.21; N, 10.85; Measured values: C, 79.95; H, 4.23; N, 10.87. LC-MS: Measured value: 646.29 ([M + H] + );Exact mass: 645.22.

[0170] The compounds of the present invention were prepared by a synthesis method similar to that of Compound 1, and the intermediate A and intermediate B used are shown in Table 3;

[0171] Table 3

[0172]

[0173]

[0174]

[0175] Synthesis Example 17: Synthesis of Compound 214:

[0176]

[0177] Under nitrogen protection, in a 500 ml round-bottom flask, intermediate A5 (25 mmol), raw material F1 (10 mmol), and 200 ml of toluene were successively added and stirred and mixed. After purging with nitrogen for 30 min to displace air, Pd 2 (dba) 3 (0.05 mmol), P(t-Bu) 3(0.15 mmol), sodium tert-butoxide (30 mmol), and heated under reflux for 24 h under nitrogen protection. The reaction solution was taken for TLC detection and it was found that the raw material F1 had completely reacted. After the reaction was completed, the reaction system was naturally cooled to room temperature, the solvent was removed by rotary evaporation, the residue was dissolved in ethyl acetate (150 ml), washed with water (100 ml), poured into a separatory funnel, shaken, and allowed to stand for liquid separation. After liquid separation, the aqueous phase was extracted with ethyl acetate (50 ml * 3). The combined organic phases were dried over anhydrous magnesium sulfate, filtered, and the filtrate was concentrated by rotary evaporation to remove ethyl acetate to obtain the crude product. The crude product was purified by silica gel column chromatography to obtain Compound 214. Elemental analysis results (molecular formula C 39 H 26 N 6 O): theoretical values: C, 78.77; H, 4.41; N, 14.13; measured values: C, 78.75; H, 4.45; N, 14.10. LC-MS: measured value: 595.30 ([M + H] + ); exact mass: 594.22.

[0178] Synthesis Example 18: Synthesis of Compound 272:

[0179]

[0180] Compound 272 was prepared according to the synthesis method of Compound 214 in Example 17, with the difference that Intermediate A6 was selected to replace Intermediate A5 and raw material F2 was selected to replace raw material F1, respectively. Elemental analysis (molecular formula C 39 H 26 N 6 S): theoretical values: C, 76.70; H, 4.29; N, 13.76; S, 5.25; measured values: C, 76.74; H, 4.26; N, 13.73; S, 5.26. LC-MS: measured value: 611.47 ([M + H] + ); exact mass: 610.19.

[0181] IV Determination of the physical properties of the compound

[0182] Determination method: The refractive index n and extinction coefficient k (isotropic glass substrate) were measured by an ellipsometer (model: ALPHA-SE, J.A. Woollam Co., USA) (tested in an atmospheric environment); the band gap Eg was tested by a double-beam ultraviolet-visible spectrophotometer (model: TU-1901, Beijing Purkinje General Instrument Co., Ltd.); the heat resistance experiment was carried out on a thermal stability device (model BOF-800C-8D).

[0183] Using the above measurement method, the compounds of the present invention and comparative compounds CP-1, CP-2, CP-3, CP-4, and CP-5 were measured. All the test result data are shown in Tables 4 and 5 below.

[0184] Table 4

[0185]

[0186]

[0187] Table 5

[0188]

[0189] Note: The evaporation temperature is the evaporation temperature of the material when TS (TS is the vertical distance from the evaporation substrate to the evaporation source) is 500 mm, the vacuum degree < 1.0E-5 Pa, and the evaporation rate is ; The judgment criterion for material decomposition is: HPLC before heat resistance minus HPLC after heat resistance > 0.1%, that is, when the difference in HPLC before and after heat resistance is greater than 0.1%, it can be determined as decomposition.

[0190] From the data in Table 4 above, it can be seen that compared with the comparative compounds CP-1, CP-2, CP-3, CP-4, and CP-5, the compounds of the present invention have higher refractive indices under blue light, green light, and red light, which is beneficial to improving the light extraction efficiency of OLED devices. At the same time, while the compounds of the present invention have higher refractive indices under blue light, green light, and red light, the compounds of the present invention have a suitable difference in refractive indices between blue light and red light, within the range of 0.21 - 0.26, which is comprehensively beneficial to reducing color shift and thus improving the viewing deviation effect of the screen. The compounds of the present invention have a high extinction coefficient at a wavelength of 380 nm in the ultraviolet region, which will effectively absorb high-energy external light sources in the ultraviolet region to minimize damage to the organic materials inside the organic light-emitting device, thereby contributing to significantly improving the stability and service life of the organic light-emitting device.

[0191] The compound of general formula (1) of the present invention has a high refractive index in the visible light field. After being applied as a cover layer to an OLED device, it can effectively improve the light extraction efficiency of the OLED device and reduce power consumption.

[0192] From the data in Table 5 above, it can be seen that compared with the comparative compounds CP-2 and CP-5, the compounds of the present invention have a lower evaporation temperature, and the decomposition temperature of the material is higher than the evaporation temperature of the material, thus ensuring thermal stability at the evaporation temperature.

[0193] In summary, the compounds of the present invention have good thermal stability, a relatively appropriate Eg energy level, a large extinction coefficient k@380nm; and excellent refractive indices under blue, green, and red lights, especially a suitable difference range between the refractive indices under blue light and red light.

[0194] V Device Examples

[0195] The following device examples are provided to further illustrate the beneficial technical effects of the compounds of the present invention when used as a cover layer in OLED devices.

[0196] 1. Materials, Equipment, and Test Methods Used in the Examples

[0197] Source of Materials: Commercially purchased or synthesized by referring to the literature in the prior art.

[0198] The molecular structural formulas of the related materials are shown below:

[0199]

[0200] Equipment:

[0201] Vacuum Evaporation Apparatus: 200*200mm evaporation equipment from Nagatec Industry Co., Ltd., Japan

[0202] Test Methods:

[0203] Determination of Current Efficiency, CIEx, CIEy, and Just Noticeable Color Difference (JNCD):

[0204] Using an IVL (Current-Voltage-Brightness) test system (Suzhou Fosida Scientific Instruments Co., Ltd.), select software EILV20060707 to test the OLED devices in the following device examples and device comparative examples, and simultaneously obtain data such as the IVL characteristic curve, efficiency-current density relationship curve, and color coordinate position of the device. The test process must be carried out in a dark environment under a masking device. Based on the data under the condition of @10mA / cm 2 Condition (i.e., the performance values corresponding to the test current density reaching 10mA / cm 2 )

[0205] 2. Device Examples

[0206] (1) Cover Layers with Different Film Thicknesses

[0207] Prepare devices with the compounds of the present invention and the comparative material CP-5 as the cover layer, change the thickness of the cover layer, and measure the performance of the devices.

[0208] Structure and Fabrication Method of Device Example 1-1:

[0209] Device Structure: Substrate layer 100 / First electrode (anode) layer 200 (ITO (15 nm) / Ag (150 nm) / ITO (15 nm)) / Hole injection layer 310 (HT-1:HI-1 = 97:3 by mass ratio, thickness 10 nm) / Hole transport layer 320 (HT-1, thickness 135 nm) / Electron blocking layer 330 (EB-1, thickness 5 nm) / Light-emitting layer 340 (BH-1:BD-1 = 97:3 by mass ratio, thickness 20 nm) / Hole blocking / electron transport layer 360 (ET-1:LiQ = 1:1 by mass ratio, thickness 35 nm) / Electron injection layer 370 (Yb, thickness 1 nm) / Second electrode (cathode) layer 400 (Mg:Ag = 1:9 by mass ratio, thickness 13 nm) / Cover layer 500 (Compound 1 of the present invention, thickness 60 nm).

[0210] Fabrication Method: The substrate layer is a PI film. The ITO (15 nm) / Ag (150 nm) / ITO (15 nm) anode layer is washed, that is, alkali washing, pure water washing, and drying are carried out in sequence, and then ultraviolet-ozone washing is carried out to remove organic residues on the surface of the anode layer. On the anode layer after the above washing, using a vacuum evaporation device, HT-1 and HI-1 with a thickness of 10 nm are evaporated as the hole injection layer, and the mass ratio of HT-1 and HI-1 is 97:3. Then, HT-1 with a thickness of 135 nm is evaporated as the hole transport layer. Subsequently, EB-1 with a thickness of 5 nm is evaporated as the electron blocking layer. After the evaporation of the above electron blocking material is completed, the light-emitting layer of the OLED light-emitting device is fabricated, which uses BH-1 as the host material and BD-1 as the doping material, and the mass ratio of BH-1 and BD-1 is 97:3, and the film thickness of the light-emitting layer is 20 nm. After the above light-emitting layer, ET-1 and LiQ are continuously evaporated by vacuum evaporation, and the mass ratio of ET-1 and LiQ is 1:1, and the film thickness is 35 nm. This layer is the hole blocking / electron transport layer. On the hole blocking / electron transport layer, a Yb layer with a thickness of 1 nm is fabricated by a vacuum evaporation device, and this layer is the electron injection layer. On the electron injection layer, a Mg:Ag electrode layer with a thickness of 13 nm is fabricated by a vacuum evaporation device, and the mass ratio of Mg and Ag is 1:9, and this layer is used as the cathode layer. On the cathode layer, Compound 1 of the present invention with a thickness of 60 nm is vacuum-evaporated as the cover layer.

[0211] Device Examples 1-2 to 1-5

[0212] The device structure and fabrication method are similar to those of Device Example 1-1, except that: the film thicknesses of the cover layer are 65 nm, 70 nm, 75 nm, and 80 nm respectively, as described in Table 6 below.

[0213] Comparative Device Examples 1-1 to 1-5

[0214] The device structure and manufacturing method are similar to those of Device Example 1-1, except that: the comparative compound CP-5 is used as the covering layer material of the OLED device; and the film thicknesses of the covering layer are 60nm, 65nm, 70nm, 75nm, and 80nm respectively, as described in Table 6 below.

[0215] Table 6

[0216]

[0217]

[0218] Note: Index = current efficiency / CIEy, and it is only applicable to blue light devices. Generally, the quality of blue light device efficiency is not referenced by current efficiency, but by Index (industry standard);

[0219] During the process of device fabrication by evaporation, there are errors and fluctuations in the film thickness. It is impossible to be accurate within the range of 1nm. It is very likely that the set film thickness by the equipment is 70nm, but the actual film thickness finally evaporated is within the range of 65 - 75nm, and even the fluctuation range may be wider, which depends on the accuracy of the equipment itself. The wider the optimal film thickness range, the smaller the impact on device efficiency. A fluctuation of Index within 1% is considered data of devices at the same level. From the data in Table 7 above, it can be seen that compared with the comparative compound CP-5, when the covering layer is 60 - 80nm, the efficiency of the OLED device containing Compound 1 of the present invention (with Index as the reference data) fluctuates within the range of 228.44 - 235.88 cd / A / CIEy; while for the comparative compound CP-5, its fluctuation range is within 199.78 - 209.55. Obviously, the efficiency of the OLED device containing the compound of the present invention is higher and the fluctuation amplitude is smaller, indicating that the device efficiency is less affected by the film thickness. Therefore, a wider film thickness can be allowed during device fabrication while maintaining the stability of high device efficiency.

[0220] (2) Blue Light Device Example

[0221] Structure of the blue light device in Embodiment B-1: Substrate layer 100 / First electrode (anode) layer 200 (ITO (15 nm) / Ag (150 nm) / ITO (15 nm)) / Hole injection layer 310 (HT-1:HI-1 = 97:3 mass ratio, thickness 10 nm) / Hole transport layer 320 (HT-1, thickness 135 nm) / Electron blocking layer 330 (EB-1, thickness 5 nm) / Light emitting layer 340 (BH-1:BD-1 = 97:3 mass ratio, thickness 20 nm) / Hole blocking / electron transport layer 360 (ET-1:LiQ = 1:1 mass ratio, thickness 35 nm) / Electron injection layer 370 (Yb, thickness 1 nm) / Second electrode (cathode) layer 400 (Mg:Ag = 1:9 mass ratio, thickness 13 nm) / Cover layer 500 (Compound 1 of the present invention, thickness 70 nm).

[0222] Fabrication method: The substrate layer is a PI film. The ITO (15 nm) / Ag (150 nm) / ITO (15 nm) anode layer is washed, that is, alkali washing, pure water washing, and drying are carried out in sequence, and then ultraviolet-ozone washing is carried out to remove organic residues on the surface of the anode layer. On the anode layer after the above washing, using a vacuum evaporation device, HT-1 and HI-1 with a film thickness of 10 nm are evaporated as the hole injection layer, and the mass ratio of HT-1 and HI-1 is 97:3. Then, HT-1 with a thickness of 135 nm is evaporated as the hole transport layer. Subsequently, EB-1 with a thickness of 5 nm is evaporated as the electron blocking layer. After the evaporation of the above electron blocking material is completed, the light emitting layer of the OLED light emitting device is fabricated, which uses BH-1 as the host material and BD-1 as the doping material, and the mass ratio of BH-1 and BD-1 is 97:3, and the film thickness of the light emitting layer is 20 nm. After the above light emitting layer, ET-1 and LiQ are continuously evaporated by vacuum evaporation, and the mass ratio of ET 1 and LiQ is 1:1, and the film thickness is 35 nm. This layer is the hole blocking / electron transport layer. On the hole blocking / electron transport layer, a Yb layer with a film thickness of 1 nm is fabricated through a vacuum evaporation device, and this layer is the electron injection layer. On the electron injection layer, a Mg:Ag electrode layer with a film thickness of 13 nm is fabricated through a vacuum evaporation device, and the mass ratio of Mg and Ag is 1:9, and this layer is used as the cathode layer. On the cathode layer, 70 nm of Compound 1 of the present invention is vacuum evaporated as the cover layer.

[0223] Blue light device Examples B-2 to B-18

[0224] The device structure and fabrication method are similar to those of Device Example B-1, except that other compounds of the present invention are used as the cover layer material; the specific compounds are as described in Table 7 below.

[0225] Blue light device Comparative Examples B-01 to B-05

[0226] The device structure and manufacturing method are similar to those of Device Example B-1, except that a comparative compound is used as the covering layer material; the specific compounds are as described in Table 7 below.

[0227] The test data of the material of the covering layer in the OLED device, the current efficiency of the device, CIEx, CIEy, and the perceptible color difference are listed in Table 7.

[0228] Table 7

[0229]

[0230]

[0231] Note: Index = current efficiency / CIEy, and it is only applicable to blue light devices. Generally, the quality of blue light device efficiency is not referenced by current efficiency, but by Index (industry standard); the perceptible color difference, unit: JNCD; 1 JNCD = 0.004

[0232] The data in Table 7 show that compared with the blue light device Comparative Examples B-01, B-02, B-03, B-04, and B-05, the Index of the blue light OLED device prepared with the compound of the present invention as the covering layer is significantly improved, and the perceptible color difference is smaller, so the angle change amount is smaller, and the color shift effect is significantly improved.

[0233] It should be understood that the smaller the perceptible color difference, the smaller the chromaticity change amount, which means that the angle dependence of the emission light wavelength of the organic electroluminescent device is suppressed better.

[0234] In summary, the compound of the present invention used as the covering layer for the OLED device significantly improves the light extraction efficiency, significantly improves the current efficiency, and improves the angle dependence.

[0235] In conclusion, the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A monoamine organic compound containing an imidazole heterocyclic group and a benzo heterocyclic group, characterized in that, the structure of the monoamine organic compound is shown as general formula (I-2): In general formula (I-2), X represents O or S; m＝1； L represents a single bond, a phenylene group; L 1 represents a single bond, a phenylene group; L, L 1 may be the same or different; R represents a phenyl group; Ar 1 represents one of dibenzofuranyl, N-phenylcarbazolyl, dibenzothiophenyl, benzoxazolyl, benzothiazolyl, phenyl-substituted or unsubstituted imidazo[1,2-a]pyridinyl.

2. A monoamine organic compound containing an imidazole heterocyclic group and a benzo heterocyclic group, characterized in that, the structure of the monoamine organic compound is shown as general formula (II-1), general formula (II-3), general formula (II-4) or general formula (II-6); In general formula (II-1), general formula (II-3), general formula (II-4) and general formula (II-6), X represents O or S; m＝1； L represents a single bond, a phenylene group; L 1 represents a single bond, a phenylene group, a pyridylene group; L, L 1 may be the same or different; R represents a hydrogen atom or a phenyl group; Ar 1 represents one of phenyl, naphthyl, biphenylyl, phenanthryl, benzophenanthryl, dibenzofuranyl, N-phenylcarbazolyl, dibenzothiophenyl, benzoxazolyl, benzothiazolyl.

3. The monoamine organic compound according to claim 1, characterized in that, the structure of the monoamine organic compound is shown as general formula (IV-2) or (IV-8); In general formula (IV-2), the X and X 1 each occurrence is the same or different and represents -O- or -S-; the X and X 1 may be the same or different; In General Formulas (IV-2) and (IV-8), L and L 1 are as defined in claim 1, and R is as defined in claim 1.

4. The monoamine organic compound according to claim 2, characterized in that, the structure of the monoamine organic compound is shown as general formula (IV-3), (IV-4), (IV-5) or (IV-6); In general formulas (IV-3), (IV-4), (IV-5) and (IV-6), the X, X 1 each occurrence independently represents -O- or -S-; the X, X 1 may be the same or different; In general formulas (IV-3), (IV-4), (IV-5) and (IV-6), L and L 1 are as defined in claim 2, and R is as defined in claim 2.

5. The monoamine organic compound according to claim 1, characterized in that, the specific structural formula of the monoamine organic compound is any one of the following structures:

6. The monoamine organic compound according to claim 2, characterized in that, the specific structural formula of the monoamine organic compound is any one of the following structures:

7. The monoamine organic compound according to any one of claims 1-6, characterized in that, the extinction coefficient of the monoamine organic compound at a wavelength of 380 nm ranges from 0.9 to 1.3; the refractive index at a wavelength of 450 nm under blue light ranges from 2.33 to 2.45, the refractive index at a wavelength of 525 nm under green light ranges from 2.14 to 2.24; the refractive index at a wavelength of 620 nm under red light ranges from 2.10 to 2.20; and the difference in refractive index between blue light and red light is 0.21 to 0.26, and the evaporation temperature of the organic compound is less than the decomposition temperature, and the evaporation temperature is 300-360 °C.

8. The monoamine organic compound according to claim 7, characterized in that, the refractive index of the monoamine organic compound at a wavelength of 450 nm under blue light ranges from 2.38 to 2.

45.

9. The monoamine organic compound according to claim 7, characterized in that, the refractive index of the monoamine organic compound at a wavelength of 620 nm under red light ranges from 2.12 to 2.

17.

10. The monoamine organic compound according to claim 7, characterized in that, the evaporation temperature of the monoamine organic compound is 320-360 °C.

11. The monoamine organic compound according to claim 7, characterized in that, the evaporation temperature of the monoamine organic compound is 330-355 °C.

12. An organic electroluminescent device, the organic electroluminescent device comprises: a substrate layer; a first electrode, the first electrode being on the substrate; an organic light-emitting functional layer, the organic light-emitting functional layer being on the first electrode; a second electrode, which is on the organic light-emitting functional layer; and a covering layer, which is on the second electrode; It is characterized in that the covering layer contains one or more of the monoamine organic compounds containing imidazole heterocyclic groups and benzheterocyclic groups according to any one of claims 1-6.

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