Compounds for reflective electrode protective layers and backlight-emitting elements containing said compounds.

Abstract

This invention provides a compound for a reflective electrode protective layer of a back-emitting element, represented by the following chemical formula 1. <Chemical Formula 1>

Description

Technical Field

[0001] This invention relates to a compound for a reflective electrode protective layer and a backlight-emitting element comprising said compound. Background Technology

[0002] Materials used as organic layers in organic light-emitting elements can be broadly classified according to their function into light-emitting materials, hole injection materials, hole transport materials, electron transport materials, and electron injection materials.

[0003] Furthermore, the luminescent materials can be classified according to their luminescence mechanism into fluorescent materials originating from the singlet excited state of electrons, phosphorescent materials originating from the triplet excited state of electrons, and delayed fluorescent materials originating from the electron movement from the triplet excited state to the singlet excited state. They can also be classified according to their luminescence color into blue, green, red, and yellow and vermilion luminescent materials required to achieve a more superior natural color.

[0004] A typical organic light-emitting device (OLED) can be structured with an anode formed on the top of a substrate, and a hole transport layer, a light-emitting layer, an electron transport layer, and a cathode sequentially formed on top of the anode. The hole transport layer, the light-emitting layer, and the electron transport layer are organic thin films composed of organic compounds.

[0005] The driving principle of the organic light-emitting element with the structure described above is as follows.

[0006] When a voltage is applied between the anode and cathode, holes injected from the anode move to the light-emitting layer via the hole transport layer, while electrons injected from the cathode move to the light-emitting layer via the electron transport layer. The holes and electrons recombine in the light-emitting layer to generate excitons. Light is generated during the transition of these excitons from the excited state to the ground state.

[0007] Furthermore, the efficiency of organic light-emitting elements can generally be divided into internal luminous efficiency and external luminous efficiency. Internal luminous efficiency is related to the efficiency of generating excitons and achieving light conversion in the organic layers between the first and second electrodes, such as hole transport layers, light-emitting layers, and electron transport layers. Theoretically, the internal luminous efficiency of fluorescence is 25%, while that of phosphorescence is 100%.

[0008] For the front-emitting light-emitting element described above, efforts have been made to develop a cover material with a high refractive index for light extraction.

[0009] Conversely, for back-emitting elements, light reflected from the reflective cathode is emitted towards the transparent anode side, which drives the thin-film transistor. In this case, Alq3, which has excellent thermal stability, is typically used as the protective film to protect the reflective electrode from corrosion, a common problem with organic light-emitting elements. However, because ash is generated during deposition, resulting in an uneven protective film, gaps form between the electrode and the protective film, allowing moisture or oxygen to penetrate, leading to a shorter lifespan. To overcome these drawbacks, organic protective film compounds are used as the material for the protective film. However, to improve the lifespan of increasingly larger back-emitting elements, efforts have been made to develop a reflective electrode protective film compound that can form a more uniform film, has a lower deposition temperature, and excellent thermal stability. Summary of the Invention

[0010] Therefore, the object of the present invention is to provide a backlighting element whose service life is further improved by equipping it with a protective layer that can protect the interior of the reflective electrode and the backlighting element under the influence of moisture, oxygen and external pollution, form a uniform thin film and have excellent thermal stability.

[0011] Next, we will provide a detailed explanation of the topics mentioned above, as well as any additional topics.

[0012] As a means of solving the problems mentioned above,

[0013] As an embodiment of the present invention, a compound for a reflective electrode protective layer of a back-emitting element represented by the following chemical formula 1 is provided:

[0014] <Chemical Formula 1>

[0015]

[0016] In the chemical formula 1,

[0017] Ar1 and Ar2 are each independently a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group.

[0018] L is a substituted or unsubstituted C6-C50 arylene or a substituted or unsubstituted C2-C50 heteroarylene.

[0019] L1 and L2 are each independently a directly bonded, substituted or unsubstituted C6-C50 arylene, or a substituted or unsubstituted C2-C50 heteroarylene.

[0020] Dashed lines may or may not form fused groups when connected.

[0021] Furthermore, as an embodiment of the present invention,

[0022] A backlight-emitting element is provided, comprising: a first electrode and a second reflective electrode; one or more organic layers disposed inside the first electrode and the second reflective electrode; and a reflective electrode protective layer disposed outside the second reflective electrode, containing a compound for the reflective electrode protective layer.

[0023] The reflective electrode protective layer compound according to the present invention is an aromatic amine compound containing four or more amine groups while having a structure in which the substituent volume characteristics at the end of the compound are minimized. Because of its excellent intermolecular film arrangement, it can effectively improve the stability of the back-emitting element under oxygen, moisture, and external contamination. Furthermore, because the high purity of the synthesized compound can be easily ensured, foreign matter formation during deposition is suppressed. In addition, because it contains extended aryl, fused aryl, or heteroaryl groups, it has a high glass transition temperature (Tg) and a high decomposition temperature (Td), thus preventing intermolecular recrystallization and maintaining the stability of the film when heat is generated during the driving of the back-emitting element, thereby achieving a lower deposition temperature.

[0024] Next, we will explain in detail the effects described above and the additional effects. Attached Figure Description

[0025] Figure 1 This is a schematic cross-sectional view illustrating the configuration of a backlight element according to an embodiment of the present invention.

[0026] Figure 2 This is a SEM image used to measure the uniformity of a thin film.

[0027] [Symbol Explanation]

[0028] 200: Hole injection layer

[0029] 300: Hole Transport Layer

[0030] 400: Emissive layer

[0031] 500: Electron transport layer

[0032] 600: Electron Injection Layer

[0033] 1000: Electrode 1 (Anode, transparent electrode)

[0034] 2000: Second electrode (cathode, reflective electrode)

[0035] 3000: Reflective electrode protective layer Detailed Implementation

[0036] Before providing a detailed description of the invention, it should be understood that the terminology used in this specification is for describing specific embodiments only and is not intended to limit the scope of the invention, which should be defined only by the scope of the appended claims. Unless otherwise expressly stated, all technical and scientific terms used in this specification have the same meaning as commonly understood by one of ordinary skill in the art.

[0037] Throughout this specification and the claims, unless otherwise expressly stated, the terms "comprise," "comprises," or "comprising" are used only to indicate that the mentioned object, step, or series of objects and steps are included, and do not preclude any other object, step, or series of objects or steps.

[0038] Throughout this specification and the claims, the term "aryl" may refer to substances including phenyl, benzyl, naphthyl, biphenyl, terphenyl, fluorene, phenanthrene, triphenylene, phenylene, etc. Benzyl, fluoranyl, benzo[a]fluorene, benzo[a]triphenylene, benzo[a] "Hyperaryl" refers to aromatic rings with C5-50 groups, including pyrrole, anthracene, piracene, and pyrene rings. "Heteroaryl" refers to groups containing pyrrole, pyrazinyl, pyridinyl, indole, isoindole, furanyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, benzothiophene, dibenzothiophene, quinolinyl, isoquinolinyl, quinoxalinyl, carbazolyl, phenanthridine, acridine, phenanthridine, thiophene, and those composed of pyridine, pyrazine, pyrimidine, pyridazine, triazine, indole, quinoline, acridine, pyrrolidine, and diphenyl rings. Alkyl ring, piperidine ring, morpholine ring, piperazine ring, carbazole ring, furan ring, thiophene ring, azole ring, A C2-50 aromatic ring containing one or more heterocyclic elements, consisting of a heterocyclic group composed of diazole ring, benzofuran ring, thiazole ring, thiadiazole ring, benzothiophene ring, triazole ring, imidazole ring, benzimidazole ring, pyran ring, dibenzofuran ring, etc.

[0039] In addition, Ar in the chemical formula x (where x is an integer) unless otherwise explicitly defined, L represents a substituted or substituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group, L x (where x is an integer) unless otherwise explicitly defined, R represents a directly bonded, substituted or unsubstituted C6–C50 arylene, or a substituted or unsubstituted C2–C50 heteroarylene, R x(where x is an integer) Unless otherwise explicitly defined, it means hydrogen, deuterium, halogen, nitro, nitrile, substituted or unsubstituted C1-C30 alkyl, substituted or unsubstituted C2-C30 alkenyl, substituted or unsubstituted C1-C30 alkoxy, substituted or unsubstituted C1-C30 mercapto, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl.

[0040] Throughout this specification and the claims, the term "substituted or unsubstituted" means derived from deuterium, halogen, amino, cyano, nitrile, nitro, nitrosyl, aminosulfonyl, isothiocyanate, thiocyanate, carboxyl, or C1-C30 alkyl, C1-C30 alkylsulfinyl, C1-C30 alkylsulfonyl, C1-C30 alkylthioalkyl, C1-C12 fluoroalkyl, C2-C30 alkenyl, C1-C30 alkoxy, C1-C12 N The designation may include any one or more groups selected from the group consisting of alkylamino, C2-C20 N,N-dialkylamino, substituted or unsubstituted C1-C30 mercapto, C1-C6 N-alkylaminosulfonyl, C2-C12 N,N-dialkylaminosulfonyl, C3-C30 silyl, C3-C20 cycloalkyl, C3-C20 heterocycloalkyl, C6-C50 aryl, and C2-C50 heteroaryl, but is not specifically limited thereto. Furthermore, throughout this specification, unless otherwise expressly stated, the same symbols have the same meaning.

[0041] Furthermore, unless otherwise expressly stated to the contrary, various embodiments of the present invention may be combined with certain other embodiments. The embodiments of the present invention and their effects will now be described.

[0042] The present invention will now be described in detail.

[0043] The compound used for the reflective electrode protective layer of the back-emitting element according to the present invention can be represented by the following chemical formula 1:

[0044] <Chemical Formula 1>

[0045]

[0046] In the chemical formula 1,

[0047] Ar1 and Ar2 are each independently a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group.

[0048] L is a substituted or unsubstituted C6-C50 arylene or a substituted or unsubstituted C2-C50 heteroarylene.

[0049] L1 and L2 are each independently a directly bonded, substituted or unsubstituted C6-C50 arylene, or a substituted or unsubstituted C2-C50 heteroarylene.

[0050] Dashed lines may or may not form fused groups when connected.

[0051] Specifically, Formula 1 may contain one or more carbazole groups connected by dashed lines. More specifically, it may contain two or more carbazole groups connected by dashed lines, for example, it may simultaneously contain a carbazole group connected by L1 and an adjacent dashed line, and a carbazole group connected by L2 and an adjacent dashed line. This allows for a higher glass transition temperature (Tg), thereby effectively improving the thermal stability during device operation.

[0052] In the chemical formula 1, Ar1 and Ar2 can each be independently an aryl group with 6 or fewer carbon atoms, or a heteroaryl group with 5 or fewer carbon atoms. This allows for improvement in the thermal stability of the compound during deposition by lowering the deposition temperature.

[0053] In the chemical formula 1, L, L1, and L2 can each be independently phenylene or a heteroarylene group with fewer than 5 carbon atoms. This allows for improvement in the thermal stability of the compound during deposition by lowering the deposition temperature.

[0054] Specifically, L can be phenylene or a 6-membered ring structure substituted with one or more nitrogen atoms. As an example, it can be phenylene, pyridyl, pyrimidinyl, or triazineyl. In the case described above, the deposition temperature can be further reduced.

[0055] Furthermore, one or more of L, L1, and L2 may have meta- or ortho-linking groups. Specifically, L may be m-phenylene, o-phenylene, m-pyridyl, or o-pyridyl. Under the conditions described above, a lower deposition temperature can be achieved, and the twisting of the compound facilitates an increase in the thickness of the protective layer, further extending the device's lifespan.

[0056] In the chemical formula 1, one or more of Ar1, Ar2, L, L1, and L2 can be pyridyl, pyrimidinyl, pyrazinyl, or triazineyl. In the case described above, excellent intermolecular arrangement can be ensured by means of nitrogen atoms, and the lifespan of the component can be effectively improved by enhancing its performance as a protective layer.

[0057] The deposition temperature of the compound of chemical formula 1 is at The temperature can be below 320℃.

[0058] The glass transition temperature (Tg) of the compound of chemical formula 1 can be above 85°C.

[0059] The following compounds are specific examples of compounds of Formula 1 according to the present invention. These examples are merely illustrative and are not intended to limit the scope of the invention.

[0060]

[0061]

[0062]

[0063]

[0064]

[0065]

[0066]

[0067]

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074] The schematic synthetic reaction formula of the compound according to an embodiment of the present invention is shown below, but is not limited thereto.

[0075] <Reaction Formula 1>

[0076]

[0077] In another embodiment of the invention, a backlight-emitting element is provided in which a reflective electrode protective layer contains the compound for reflective electrode protective layer according to the invention as described above.

[0078] Next, the back-emitting element according to the present invention will be described in more detail.

[0079] This invention provides a back-emitting element, comprising: a first electrode and a second reflective electrode; one or more organic layers disposed inside the first electrode and the second reflective electrode; and a reflective electrode protective layer disposed outside the second reflective electrode, containing a compound for the reflective electrode protective layer. Specifically, the back-emitting element can be an organic light-emitting element that emits light from the back.

[0080] The reflective electrode refers to an opaque electrode that reflects light transmitted from a light-emitting layer located inside the electrode.

[0081] The organic layer can be composed of two or more light-emitting layers stacked together, and a second protective layer can be provided on the outside of the reflective electrode protective layer. Specifically, the second protective layer can be an inorganic material, such as silicon nitride or silicon oxide.

[0082] The thickness of the reflective electrode protective layer can be 2500 to... Specifically, it could be 4000 to Under the conditions described above, the lifespan of the reflective electrode can be further improved.

[0083] Furthermore, the organic layer may include a hole transport layer, a light-emitting layer, and an electron transport layer that typically constitute the light-emitting part, but is not limited to these.

[0084] Specifically, according to one embodiment of the present invention, a back-emitting element may include one or more organic layers forming light-emitting portions such as a hole injection layer (HIL), a hole transport layer (HTL), an electron emission layer (EML), an electron transport layer (ETL), and an electron injection layer (EIL) between a first electrode (anode, transparent electrode) and a second electrode (cathode, reflective electrode). The first electrode may be a transparent electrode, and the second electrode may be a reflective electrode.

[0085] Figure 1 This is a cross-sectional view illustrating the structure of a back-emitting element according to an embodiment of the present invention. A back-emitting element according to one embodiment of the present invention can be configured as follows... Figure 1 The structure shown is manufactured.

[0086] like Figure 1As shown, the back-emitting element can be structured by stacking, from bottom to top, a first electrode 1000, a hole injection layer 200, a hole transport layer 300, a light-emitting layer 400, an electron transport layer 500, an electron injection layer 600, a second electrode 2000, and a reflective electrode protective layer 3000. The first electrode can be a transparent electrode, while the second electrode can be a reflective electrode. When light is emitted to the outside through the first electrode to emit light from the back, the second electrode, as a reflective electrode, can reflect the light generated inside back towards the first electrode.

[0087] The first electrode 1000 is used as a hole injection electrode for injecting holes into the back-side light-emitting element. To achieve hole injection, the first electrode 1000 is manufactured using a material with the lowest possible work function, and can be formed using transparent materials such as indium tin oxide (ITO), indium zinc oxide (IZO), and graphene.

[0088] Meanwhile, the hole injection layer 200 can be formed by depositing the hole injection layer material on the upper part of the first electrode 1000 using methods such as vacuum deposition, spin coating, casting, or the Langmuir-Blodgett method. When forming the hole injection layer 200 by vacuum deposition, the deposition conditions will vary depending on the compound used as the material of the hole injection layer 200, the desired structure of the hole injection layer 200, and its thermal properties. Typically, deposition temperatures of 50–500°C and 10… -8 Up to 10 -3 The vacuum level of the Torr is 0.01 to... The deposition rate and The layer thickness should be appropriately selected within the range of up to 5 μm. Furthermore, a charge generation layer can be deposited on the surface of the hole injection layer 200 as needed. Common materials can be used as the charge generation layer material, such as hexacyano-hexaazabenzophenanthrene (HATCN).

[0089] Furthermore, the hole transport layer 300 can be formed by depositing hole transport layer material on top of the hole injection layer 200 using methods such as vacuum deposition, spin coating, casting, or the Langmuir-Brønder (LB) method. When forming the hole transport layer 300 by the vacuum deposition method, the deposition conditions will vary depending on the compound used, but it is generally preferable to select conditions within a range almost identical to those for forming the hole injection layer 200. The hole transport layer 300 can be formed using known compounds. The hole transport layer 300 described above can be one or more layers, and although... Figure 1 Although not illustrated, a light-emitting auxiliary layer can be added above the hole transport layer 300.

[0090] Simultaneously, the light-emitting layer 400 can be formed by depositing a light-emitting layer material on top of the hole transport layer 300 or the light-emitting auxiliary layer using methods such as vacuum deposition, spin coating, casting, or the Langmuir-Brønder (LB) method. When forming the light-emitting layer 400 by vacuum deposition, the deposition conditions will vary depending on the compound used, but are generally preferably selected within a range of conditions almost identical to those for forming the hole injection layer 200. Known compounds can be used as the light-emitting layer material, either as the main agent or dopant.

[0091] When phosphorescent dopants are used simultaneously in the light-emitting layer material, to prevent triplet excitons or holes from diffusing into the electron transport layer 500, a stacked hole-blocking material (HBL) can be added to the upper part of the light-emitting layer 400 using vacuum deposition or spin coating. The hole-blocking material used is not particularly limited; any known material can be used. For example, it can be... Diazole derivatives or benzotriazole derivatives, o-diazaphenanthroline derivatives, or hole-blocking materials described in Japanese Patent Application Publication No. 11-329734 (A1), among which the most representative include Balq (bis(8-hydroxy-2-methylquinoline)-(4-phenylphenoxy)aluminum), phenanthroline compounds (e.g., UDC's BCP), etc. The light-emitting layer 400 of the present invention, as described above, may comprise one or more blue light-emitting layers.

[0092] Furthermore, the electron transport layer 500 is formed on top of the light-emitting layer 400 and can be formed by methods such as vacuum deposition, spin coating, or casting. The deposition conditions of the electron transport layer 500 will vary depending on the compound used, but are generally preferably selected within the same range as those for the formation of the hole injection layer 200.

[0093] Furthermore, the electron injection layer 600 can be formed by depositing electron injection layer material on the upper part of the electron transport layer 500, and can be formed by methods such as vacuum deposition, spin coating, casting, etc.

[0094] Furthermore, the second electrode 2000 serves as an electron injection electrode, capable of reflecting light generated in the light-emitting layer within the electrode. It can be formed on the upper part of the electron injection layer 600 using methods such as vacuum deposition or spin coating. Various reflective metals can be used as the material for the second electrode 2000, such as aluminum (Al) and silver (Ag), but it is not limited to these.

[0095] In addition to the aforementioned layers, the back-emitting element of the present invention can also have multiple additional layers added as needed.

[0096] Furthermore, the thickness of each organic layer formed by the present invention can be adjusted according to the desired degree, specifically from 10 to 1000 nm, and more specifically from 20 to 150 nm.

[0097] The reflective electrode protective layer 3000, as shown Figure 1 As shown, the reflective electrode is protected by forming on the outer surface of the second electrode 2000.

[0098] Next, the present invention will be described in more detail through examples of the synthesis of compounds according to an embodiment of the present invention and examples of the manufacture of back-emitting elements. The following synthesis examples and embodiments are merely illustrative of the present invention, and the scope of the present invention is not limited to the following examples.

[0099] Synthesis Example 1: Synthesis of Compound 37

[0100]

[0101] In a round-bottom flask, 5.0 g of 3-bromo-9-phenyl-9H-carbazole, 4.0 g of N1,N4-diphenylbenzene-1,4-diamine, 2.3 g of t-BuONa, 0.6 g of Pd2(dba)3, and 0.7 mL of (t-Bu)3P were dissolved in 150 mL of toluene and refluxed with stirring. The reaction was confirmed by thin-layer chromatography (TLC), and the reaction was stopped after the addition of water. The organic layer was extracted with MC (methylene chloride) and recrystallized under reduced pressure after filtration to give 7.8 g of compound 37 (yield 68%).

[0102] m / z: 742.31 (100.0%), 743.31 (59.9%), 744.32 (17.0%), 745.32 (3.2%)

[0103] Synthesis Example 2: Synthesis of Compound 133

[0104]

[0105] Compound 133 was synthesized by substituting 3-bromo-9-phenyl-9H-carbazole with 9-(4-bromophenyl)-9H-carbazole (yield 70%).

[0106] m / z: 742.31 (100.0%), 743.31 (59.9%), 744.32 (17.0%), 745.32 (3.2%)

[0107] Synthesis Example 3: Synthesis of Compound 41

[0108]

[0109] Compound 41 was synthesized by substituting N1,N4-diphenylbenzene-1,4-diamine with N1,N3-diphenylbenzene-1,3-diamine, following the same method as in Synthetic Example 1 (yield 65%).

[0110] m / z: 742.31 (100.0%), 743.31 (59.9%), 744.32 (17.0%), 745.32 (3.2%)

[0111] Synthesis Example 4: Synthesis of Compound 160

[0112]

[0113] Compound 160 was synthesized by substituting N1,N4-diphenylbenzene-1,4-diamine with N2,N6-diphenylpyridine-2,6-diamine (yield 63%).

[0114] m / z: 743.30 (100.0%), 744.31 (57.7%), 745.31 (17.4%), 746.31 (3.3%), 744.30 (1.8%)

[0115] Synthesis Example 5: Synthesis of Compound 49

[0116]

[0117] Compound 49 was synthesized by substituting N1,N4-diphenylbenzene-1,4-diamine with N4,N4'-diphenyl-[1,1'-biphenyl]-4,4'-diamine (yield 67%).

[0118] m / z: 818.34 (100.0%), 819.34 (66.4%), 820.35 (21.0%), 821.35 (4.4%)

[0119] Manufacturing of back-lit elements

[0120] According to Figure 1 The structure shown creates a back-emitting element. The back-emitting element is formed by stacking the following layers from bottom to top: substrate 100 / anode (hole injection electrode, transparent electrode 1000) / hole injection layer 200 / hole transport layer 300 / light-emitting layer 400 / electron transport layer 500 / electron injection layer 600 / cathode (electron injection electrode, reflective electrode 2000) / reflective electrode protective layer 3000.

[0121] The compounds used in the organic layer located inside the electrode of the back-side light-emitting element of the present invention are shown in Table 1 below.

[0122] Table 1

[0123]

[0124] Example 1

[0125] A film is formed on top of an indium tin oxide (ITO) substrate to serve as a hole injection layer. HI01, HATCN and its role as a hole transport layer The HT01 was then doped with 3% BH01:BD01 to form a film. The light-emitting layer is then formed. Next, a film is formed as an electron transport layer. ET01:Liq (1:1) was deposited afterward. An electron-injected layer is formed by the deposition of LiF. Subsequently, it is deposited as a reflective electrode. A layer of Al with a thickness of [thickness] is deposited on top of the reflective electrode (cathode) to form a protective layer for the reflective electrode. Compound 37, produced in Synthesis Example 1, was of a thickness that was used in this study. A back-emitting element was manufactured by encapsulating the element in a glove box.

[0126] Examples 2 to 5

[0127] Following the same method as in Example 1, back-emitting elements were fabricated by forming a reflective electrode protective layer using the compounds produced in Synthesis Examples 2 to 5.

[0128] Example 6

[0129] Following the same method as in Example 1, a film was formed as a protective layer for the reflective electrode. The thickness of the compound 37 produced by Synthesis Example 1 was used to manufacture a back-emitting element.

[0130] Example 7

[0131] Following the same method as in Example 1, a film was formed as a protective layer for the reflective electrode. The thickness of the compound 37 produced by Synthesis Example 1 was used to manufacture a back-emitting element.

[0132] Comparative Example 1 and Comparative Example 2

[0133] Back-emitting elements were fabricated by forming reflective electrode protective layers using comparative compound 1 (Ref. 1) and comparative compound 2 (Ref. 2) as shown in Table 2 below, respectively, in the same manner as in Example 1.

[0134] Table 2

[0135]

[0136] Comparative Example 3: Manufacturing of Front-Emitting Light Elements

[0137] A hole injection layer is formed on top of an indium tin oxide (ITO) substrate having an Ag-containing reflective layer. HI01, HATCN and its role as a hole transport layer The HT01 was then doped with BH01:BD01 3% to form a film. The light-emitting layer is then formed. Next, a film is formed to serve as the electron transport layer. ET01:Liq (1:1) was deposited afterward. An electron-injected layer is formed by LiF. Next, MgAg is deposited at a thickness of 15 nm as a transparent electrode (cathode), and then comparative compound 1 (Ref. 1) is applied as a light efficiency improvement layer above the cathode. A thickness of [amount missing] is deposited. A front-facing light-emitting element is fabricated by encapsulating the element within a glove box.

[0138] Component performance evaluation

[0139] By injecting electrons and holes by applying a voltage to a Kiethley 2400 source measurement unit and measuring the brightness of the emitted light using a Konica Minolta spectroradiometer (CS-2000), the performance of the components of Examples 1 to 7 and Comparative Examples 1 to 3 was evaluated under atmospheric pressure conditions, namely, the current density and brightness relative to the applied voltage. The results are shown in Table 3 below.

[0140] Table 3

[0141] Op.V <![CDATA[mA / cm 2 ]]> Cd / A LT50 Example 1 3.5 10 9.0 1040 Example 2 3.5 10 9.0 1035 Example 3 3.5 10 9.0 1065 Example 4 3.5 10 9.0 1075 Example 5 3.5 10 9.0 1020 Example 6 3.5 10 9.0 1320 Example 7 3.5 10 9.0 1310 Comparative Example 1 3.5 10 9.0 790 Comparative Example 2 3.5 10 9.0 670 Comparative Example 3 3.6 10 4.3 900

[0142] It can be observed that, compared to Comparative Examples 1 and 2, the compound of the present invention has a minimized volume characteristics at the terminal portion and contains an aromatic amine structure with four or more amine groups. Therefore, it does not form bubbles or recrystallize on the deposited surface and sides, thereby allowing for stable film formation. This effectively improves the stability of the device under oxygen, moisture, and external contamination, and significantly improves its lifespan. Furthermore, it can be observed that the back-emitting structure of the present invention uses [specific features] to protect the reflective electrode and extend its lifespan. Electrode protective layers of the above thickness are preferable, but they are stacked in the front-emitting light-emitting structure shown in Comparative Example 3. While increasing the thickness of the light efficiency improvement layer can improve light transmission, it can also lead to a significant decrease in efficiency and lifespan. Specifically, in a front-emitting structure, when a certain thickness is stacked to fully function as an electrode protection layer, the significant decrease in transmittance and light extraction efficiency ultimately disrupts the element's balance and reduces its lifespan. A comparison of Examples 6 and 7 reveals that, specifically... This can further improve service life, even in stacked systems. Even with the thicknesses mentioned above, there is no proportional improvement in service life. Therefore, it can be concluded that by applying... The range of thicknesses allows for reduced consumption of protective film materials and more effective commercialization.

[0143] Thin film uniformity measurement

[0144] Comparative compound 1 (Ref. 1), comparative compound 2 (Ref. 2), compound 37, and compound 41 were vacuum deposited on a glass substrate, respectively. After heat treatment at 100°C for 30 minutes, the top and side surfaces were measured using a scanning electron microscope (SEM, Hitachi, SU8010). The results are as follows: Figure 2 As shown. See also Figure 2 It can be observed that, compared to the comparative examples, the compounds of the present invention form uniform films on both the top and sides, indicating that stable films can be effectively formed. Although not illustrated, other compounds presented in the manufacturing examples of the present invention can also form uniform films.

Claims

1. A back-emitting element, characterized in that, Include: The first electrode and the second reflective electrode; One or more organic layers are located inside the first electrode and the second reflective electrode; and, A reflective electrode protective layer, disposed outside the second reflective electrode, contains a compound for the reflective electrode protective layer. The reflective electrode protective layer is represented by a compound with the following chemical formula 1: Chemical Formula 1 In the chemical formula 1, Ar1 and Ar2 are each independently an aryl group with a C6 to C50 structure, or a heteroaryl group with a C2 to C50 structure. L is a C6–C50 arylene or a C2–C50 heteroarylene. L1 and L2 are each independently directly bonded, C6-C50 arylene or C2-C50 heteroarylene. Dashed lines may or may not connect to form fused groups. However, it contains more than one carbazole group connected by dashed lines.

2. The back-emitting element according to claim 1, The compound used for the reflective electrode protective layer contains both a carbazole group formed by L1 and an adjacent dashed line, and a carbazole group formed by L2 and an adjacent dashed line.

3. The back-emitting element according to claim 1, Ar1 and Ar2 are each independently an aryl group with a C6 or less, or a heteroaryl group with a C5 or less.

4. The back-emitting element according to claim 1, The L, L1, and L2 are each independently phenylene or heteroaryl groups with a C5 or less.

5. The back-emitting element according to claim 1, The L is a phenylene oxide or a 6-membered ring structure substituted with one or more N atoms.

6. The back-emitting element according to claim 1, One or more of L, L1, and L2 have inter- or adjacent connection bases.

7. The back-emitting element according to claim 1, The L is m-phenylene, o-phenylene, m-pyridyl or o-pyridyl.

8. The back-emitting element according to claim 1, One or more of Ar1, Ar2, L, L1 and L2 are pyridyl, pyrimidinyl, pyrazinyl or triazineyl.

9. The back-emitting element according to claim 1, The compound of chemical formula 1 is any one of the following compounds represented by chemical formulas:

10. The back-emitting element according to claim 1, The thickness of the reflective electrode protective layer is 2500 to 11. The back-emitting element according to claim 1, The organic layer adopts a structure composed of two or more layers of light-emitting layers.

12. The back-emitting element according to claim 1, A second protective layer is also provided on the outside of the reflective electrode protective layer.

13. The back-emitting element according to claim 12, The second protective layer comprises silicon nitride or silicon oxide.

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