Compound for reflective electrode protective layer and back-emitting device containing the same

Abstract

The present invention provides a compound for a reflective electrode protective layer of a back-emitting device represented by the following Chemical Formula 1. <Chemical Formula 1> #imgabs0#

Description

Technical Field

[0001] The present invention relates to a compound for a reflective electrode protective layer and a back-light emitting device comprising the compound. Background Art

[0002] Materials used as organic layers in organic light-emitting devices can be broadly classified into light-emitting materials, hole-injecting materials, hole-transporting materials, electron-transporting materials, and electron-injecting materials according to their functions.

[0003] In addition, the luminescent materials can be divided 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 movement of electrons from the triplet excited state to the singlet excited state according to the luminescence mechanism, and can also be divided into blue, green, red, and yellow and vermilion luminescent materials required to achieve better natural colors according to the luminescent color.

[0004] A typical organic light-emitting element has an anode formed on a substrate, and a hole transport layer, a light-emitting layer, an electron transport layer, and a cathode formed on the anode in sequence. 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 having the above structure is as follows.

[0006] When a voltage is applied between the anode and cathode, holes injected from the anode move through the hole transport layer to the light-emitting layer, while electrons injected from the cathode move through the electron transport layer to the light-emitting layer. These holes and electrons recombine in the light-emitting layer to form excitons. Light is generated as these excitons transition from an excited state to a ground state.

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

[0008] For the front-emitting element described above, efforts have been made to develop a cover layer material having a high refractive index in order to extract light.

[0009] In contrast, for back-emitting elements, the light reflected by the reflective cathode is radiated toward the direction of the driving thin film transistor, that is, the transparent anode side. At this time, the protective film formed to protect the reflective electrode that is prone to corrosion of the organic light-emitting element usually uses Alq3 with excellent thermal stability. However, because ash is generated during deposition, an uneven protective film is formed, which forms a gap between the electrode and the protective film and causes the penetration of moisture or oxygen, resulting in a shorter service life. In order to compensate for the above shortcomings, organic protective film compounds are used as the material of the protective film. However, in order to improve the service life of the gradually larger back-emitting elements, efforts have been made to develop a reflective electrode protective film compound that can form a more uniform thin 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 back-emitting element with further improved service life by providing a protective layer that can protect the reflective electrode and the interior of the back-emitting element from moisture, oxygen and external contamination, forming a uniform thin film and having excellent thermal stability.

[0011] Next, the above-mentioned issues and additional issues will be described in detail.

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

[0013] As one embodiment of the present invention, a compound for a reflective electrode protective layer of a back-emitting device is provided, which is represented by the following Chemical Formula 1:

[0014] <Chemical Formula 1>

[0015]

[0016] In the chemical formula 1,

[0017] X is NAr, O, S, or CRR,

[0018] Ar, Ar1 to Ar4 are each independently a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group,

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

[0020] R, R', R1 and R2 are each independently 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 thiol, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl, and adjacent R and R' may or may not form a ring by combining with each other.

[0021] l and m are each independently an integer from 0 to 3.

[0022] In addition, as one embodiment of the present invention,

[0023] A back-emitting element is provided, comprising: a first electrode and a second reflective electrode; one or more organic layers interposed between the first electrode and the second reflective electrode; and a reflective electrode protective layer disposed outside the second reflective electrode and containing the reflective electrode protective layer compound.

[0024] The reflective electrode protective layer compound according to the present invention comprises two aromatic amine compounds connected by a three-ring fused group having a five-membered ring. Due to the excellent intermolecular film alignment, it can effectively improve the stability of the device in the presence of oxygen, moisture, and external contamination. Furthermore, since the purity of the compound can be easily improved, the formation of foreign matter during deposition is suppressed. Furthermore, when the aromatic amine groups include extended aromatic groups, fused aromatic groups, or heteroaromatic groups, they can have a higher glass transition temperature (Tg) and a higher decomposition temperature (Td). This prevents intermolecular recrystallization and maintains the stability of the film during the heat generated during the operation of the back-emitting device, thereby achieving a lower deposition temperature.

[0025] Next, the above-mentioned effects and additional effects will be described in detail. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic cross-sectional view illustrating the structure of a back-light emitting element according to an embodiment of the present invention.

[0027] Figure 2 This is a scanning electron microscope (SEM) photograph taken to measure the uniformity of the thin film.

[0028]

Explanation of symbols

[0029] 200: Hole injection layer

[0030] 300: Hole transport layer

[0031] 400: Luminous layer

[0032] 500: electron transport layer

[0033] 600: electron injection layer

[0034] 1000: 1st electrode (anode, transparent electrode)

[0035] 2000: Second electrode (cathode, reflective electrode)

[0036] 3000: Reflective electrode protective layer DETAILED DESCRIPTION

[0037] Before describing the present invention in detail, it should be understood that the terms used in this specification are intended only to describe specific embodiments and are not intended to limit the scope of the present invention, which is to be determined solely by the appended claims. Unless otherwise expressly stated, all technical and scientific terms used in this specification have the same meanings as those commonly understood by persons of ordinary skill in the art.

[0038] Throughout this specification and claims, unless expressly stated otherwise, terms such as comprise, comprise, or comprising merely indicate the inclusion of the stated item, step, or series of items and steps, and do not preclude any other item, step, or series of items or steps.

[0039] Throughout the specification and claims, the term "aryl" may refer to groups such as phenyl, benzyl, naphthyl, biphenyl, terphenyl, fluorenyl, phenanthrenyl, triphenylene, phenylene, Benzotriphenylene, benzophenone, fluoranthene, benzofluorenyl, benzotriphenylene, benzo The term "heteroaryl" refers to a C5-50 aromatic hydrocarbon ring containing an aromatic ring such as pyrrolyl, pyrazinyl, pyridyl, indolyl, isoindolyl, furyl, benzofuranyl, isobenzofuranyl, dibenzofuranyl, benzothiophenyl, dibenzothiophenyl, quinolyl, isoquinolyl, quinoxalinyl, carbazolyl, phenanthridinyl, acridinyl, phenanthrolinyl, thienyl, and a pyridine ring, pyrazine ring, pyrimidine ring, pyridazine ring, triazine ring, indole ring, quinoline ring, acridinium ring, pyrrolidine ring, dibenzothiophenyl ring, Alkane ring, piperidine ring, morpholine ring, piperazine ring, carbazole ring, furan ring, thiophene ring, Azole ring, The heterocyclic group is a C2-50 aromatic ring containing one or more hetero elements, such as a diazole ring, a benzofuran ring, a thiazole ring, a thiadiazole ring, a benzothiophene ring, a triazole ring, an imidazole ring, a benzimidazole ring, a pyran ring, or a dibenzofuran ring.

[0040] In addition, Ar in the chemical formula x (wherein x is an integer) unless otherwise specifically defined, represents a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group, L x (wherein x is an integer) unless otherwise specifically defined, represents a directly bonded, substituted or unsubstituted C6-C50 arylene group, or a substituted or unsubstituted C2-C50 heteroarylene group, R x (wherein x is an integer) unless explicitly defined otherwise, represents 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.

[0041] Throughout the present specification and claims, the term "substituted or unsubstituted" refers to a group substituted with deuterium, halogen, amino, cyano, nitrile, nitro, nitroso, sulfamoyl, isothiocyanate, thiocyanate, carboxyl, or C1-C30 alkyl, C1-C30 alkylsulfinyl, C1-C30 alkylsulfonyl, C1-C30 alkylsulfanyl, C1-C12 fluoroalkyl, C2-C30 alkenyl, C1-C30 alkoxy, C1-C12 N The present invention may be substituted or unsubstituted with one or more groups selected from the group consisting of an alkylamino group, a C2-C20 N,N-dialkylamino group, a substituted or unsubstituted C1-C30 mercapto group, a C1-C6 N-alkylsulfamoyl group, a C2-C12 N,N-dialkylsulfamoyl group, a C3-C30 silyl group, a C3-C20 cycloalkyl group, a C3-C20 heterocycloalkyl group, a C6-C50 aryl group, and a C2-C50 heteroaryl group, but is not particularly limited thereto. Furthermore, throughout the present specification, unless otherwise expressly stated, the same symbols have the same meanings.

[0042] In addition, unless otherwise explicitly stated to the contrary, the various embodiments of the present invention may be combined with other embodiments. Next, the embodiments of the present invention and their effects will be described.

[0043] Next, the present invention will be described in detail.

[0044] The compound for the reflective electrode protective layer of the back-light emitting device according to the present invention can be represented by the following Chemical Formula 1:

[0045] <Chemical Formula 1>

[0046]

[0047] In the chemical formula 1,

[0048] X is NAr, O, S, or CRR,

[0049] Ar, Ar1 to Ar4 are each independently a substituted or unsubstituted C6-C50 aryl group, or a substituted or unsubstituted C2-C50 heteroaryl group,

[0050] L1 and L2 are each independently a directly bonded, substituted or unsubstituted C6-C50 arylene group, or a substituted or unsubstituted C2-C50 heteroarylene group,

[0051] R, R', R1 and R2 are each independently 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 thiol, substituted or unsubstituted C6-C50 aryl, or substituted or unsubstituted C2-C50 heteroaryl, and adjacent R and R' may or may not form a ring by combining with each other.

[0052] l and m are each independently an integer from 0 to 3.

[0053] Specifically, in Chemical Formula 1, Ar, Ar1 to Ar4 can each independently be an aryl group having three or fewer rings, or a heteroaryl group having three or fewer rings. This can improve the thermal stability of the compound during deposition by lowering the deposition temperature.

[0054] More specifically, Ar, Ar1 to Ar4 can each independently be a monocyclic aryl group, a monocyclic heteroaryl group, a condensed bicyclic aryl group, or a condensed bicyclic heteroaryl group, thereby further improving the service life of the device.

[0055] Furthermore, at least one of Ar, Ar1 to Ar4 may be a fused aromatic group having C10 or greater.

[0056] Furthermore, two or more of Ar, Ar1 to Ar4 may each independently be a heteroaryl group having three or fewer rings and containing N. In this case, excellent intermolecular alignment can be ensured by the nitrogen atom, and the service life can be effectively improved.

[0057] In the chemical formula 1, Ar, Ar1 to Ar4 can each independently be a phenyl group, a biphenyl group, a pyridyl group, a phenylpyridyl group, a quinolyl group, a naphthyl group, or a phenanthrenyl group. In this case, even with a low molecular weight, a high glass transition temperature (Tg) can be achieved, thereby achieving excellent thermal stability during deposition and driving.

[0058] In the chemical formula 1, at least two of Ar1 to Ar4 may be the same. Specifically, Ar1 and Ar2, and Ar3 and Ar4 may be the same. In the case of adopting the above structure, it is advantageous to form a uniform thin film. Optionally, Ar1 to Ar4 may not include a fluorenyl group. In the above case, due to its excellent thermal stability, the service life of the component can be more effectively improved.

[0059] In addition, in the chemical formula 1, X may be NAr or O. In the above case, it is possible to ensure excellent thin film stability while having a lower deposition temperature.

[0060] The L1 and L2 can each independently be a direct bond, a phenyl group, or a pyridyl group, thereby preventing the distortion of the compound while achieving a lower deposition temperature.

[0061] More specifically, the chemical formula 1 can also be represented by the following chemical formula 2. In the above case, the aromatic amine can be directly bonded to the 3rd and 6th positions of the carbazole group, thereby facilitating the formation of a uniform thin film.

[0062] <Chemical Formula 2>

[0063]

[0064] In Chemical Formula 2, the definitions of Ar, Ar1 to Ar4 are the same as those in Chemical Formula 1. In addition, in the above description of Chemical Formula 1, matters related to Ar, Ar1 to Ar4 are also applicable to Chemical Formula 2, and thus the relevant detailed description will be omitted.

[0065] The deposition temperature of the compounds of Chemical Formula 1 and Chemical Formula 2 is The temperature can be below 320°C.

[0066] The glass transition temperature (Tg) of the compounds of Chemical Formula 1 and Chemical Formula 2 may be 85° C. or higher.

[0067] The following compounds are specific examples of the compound of Chemical Formula 1 according to the present invention. The following examples are merely illustrative for illustrating the present invention, and the present invention is not limited thereby.

[0068]

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075]

[0076]

[0077]

[0078]

[0079]

[0080]

[0081] The schematic synthesis reaction formula of the compound according to one embodiment of the present invention is shown below, but the present invention is not limited thereto.

[0082] <Reaction Formula 1>

[0083]

[0084] In another embodiment of the present invention, there is provided a back-light emitting device comprising a reflective electrode protective layer containing the compound for a reflective electrode protective layer according to the present invention.

[0085] Next, the back-light emitting element according to the present invention will be described in more detail.

[0086] The present invention provides a back-emitting device comprising: a first electrode and a second reflective electrode; one or more organic layers interposed between the first and second reflective electrodes; and a reflective electrode protective layer disposed outside the second reflective electrode and containing the compound described above for the reflective electrode protective layer. Specifically, the back-emitting device may be an organic light-emitting device that emits light from the back side.

[0087] The reflective electrode is an opaque electrode that reflects light transmitted from the light-emitting layer located inside the electrode.

[0088] The organic layer may be a stacked structure of two or more light-emitting layers, and a second protective layer may be provided outside the reflective electrode protective layer. Specifically, the second protective layer may be an inorganic material, such as silicon nitride or silicon oxide.

[0089] The thickness of the reflective electrode protection layer can be 2500 to Specifically, it can be 4000 to In the case described above, the service life of the reflective electrode can be further improved.

[0090] Furthermore, the organic layer may include a hole transport layer, a light emitting layer, and an electron transport layer that generally constitute a light emitting portion, but is not limited thereto.

[0091] Specifically, a back-emitting element according to one embodiment of the present invention may include one or more organic layers constituting a light-emitting portion, such as a hole injection layer (HIL), a hole transport layer (HTL), a light-emitting 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.

[0092] Figure 1 The back-light emitting element according to an embodiment of the present invention is schematically illustrated in a cross-sectional view. Figure 1 The structure shown is manufactured.

[0093] like Figure 1 As shown, a back-emitting element can have a structure that, from bottom to top, consists of 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 protection 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, generating back-emitting light, the second electrode, acting as a reflective electrode, can reflect the light generated internally back toward the first electrode.

[0094] The first electrode 1000 is used as a hole injection electrode for injecting holes into the back-emitting element. To achieve hole injection, the first electrode 1000 is made of a material with the lowest possible work function, such as indium tin oxide (ITO), indium zinc oxide (IZO), or graphene, which are transparent materials.

[0095] Meanwhile, the hole injection layer 200 can be formed by depositing a hole injection layer material on the upper portion of the first electrode 1000 using methods such as vacuum deposition, spin coating, casting, and Langmuir-Blodgett (LB) methods. When forming the hole injection layer 200 by vacuum deposition, the deposition conditions 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 the thermal properties. Generally, the deposition temperature can be 50 to 500°C, 10 -8 to 10 -3 Torr vacuum degree, 0.01 to / s deposition rate and The thickness can be appropriately selected within the range of 1 to 5 μm. In addition, a charge generation layer can be additionally deposited on the surface of the hole injection layer 200 as needed. As the charge generation layer material, a general material can be used, for example, hexacyano-hexaazatriphenylene (HATCN) can be used.

[0096] In addition, the hole transport layer 300 can be formed by depositing a hole transport layer material on the upper part of the hole injection layer 200 using a method such as vacuum deposition, spin coating, casting, Langmuir-Brøgeta (LB) method, etc. When the hole transport layer 300 is formed by the vacuum deposition method, its deposition conditions will vary depending on the compound used, but it is generally appropriate to select conditions within a range that is almost the same as the conditions for forming the hole injection layer 200. The hole transport layer 300 can be formed using well-known compounds. The hole transport layer 300 as described above can be more than one layer, and although in Figure 1 Although not shown in the figure, a luminescence auxiliary layer may be additionally formed on the hole transport layer 300 .

[0097] Meanwhile, 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, and the Langmuir-Brötten (LB) method. When forming the light-emitting layer 400 by the vacuum deposition method, the deposition conditions will vary depending on the compound used, but are generally preferably selected within a range of conditions that are substantially the same as those used for forming the hole injection layer 200. As the light-emitting layer material, known compounds can be used as a main agent or a dopant.

[0098] When a phosphorescent dopant is used in the light-emitting layer material, in order to prevent triplet excitons or holes from diffusing to the electron transport layer 500, a stacked hole blocking material (HBL) can be added on the upper part of the light-emitting layer 400 by vacuum deposition or spin coating. The hole blocking material that can be used is not particularly limited, and any known material can be used. For example, Examples of hole-blocking materials include oxadiazole derivatives, benzotriazole derivatives, o-phenanthroline derivatives, and those described in Japanese Patent Application Laid-Open No. 11-329734(A1). Representative examples include Balq (bis(8-hydroxy-2-methylquinolinol)-(4-phenylphenoxy)aluminum) and phenanthroline compounds (e.g., BCP (bathocuproine) from UDC). The light-emitting layer 400 of the present invention may include one or more blue light-emitting layers, or two or more blue light-emitting layers.

[0099] Furthermore, the electron transport layer 500 is formed on the upper portion of the light-emitting layer 400 and can be formed by methods such as vacuum deposition, spin coating, and casting. The deposition conditions of the electron transport layer 500 vary depending on the compound used, but are generally preferably selected within a range of conditions that are substantially the same as those used for forming the hole injection layer 200.

[0100] Furthermore, the electron injection layer 600 can be formed by depositing an electron injection layer material on the electron transport layer 500 , and can be formed by methods such as vacuum deposition, spin coating, and casting.

[0101] Furthermore, the second electrode 2000 serves as an electron injection electrode, reflecting light generated in the light-emitting layer within the electrode. It can be formed on top of the electron injection layer 600 by vacuum deposition or spin coating. The second electrode 2000 can be made of various reflective metals, such as aluminum (Al) and silver (Ag), but is not limited thereto.

[0102] The back-light emitting device of the present invention may further include various layers in addition to the above-mentioned layers as needed.

[0103] Furthermore, the thickness of each organic layer formed by the present invention can be adjusted as needed, and specifically can be 10 to 1000 nm, more specifically 20 to 150 nm.

[0104] The reflective electrode protection layer 3000 is as follows Figure 1 As shown, the reflective electrode is protected by being formed on the outer side surface of the second electrode 2000 .

[0105] Next, the present invention will be described in more detail by a synthesis example of a compound according to an embodiment of the present invention and an example of manufacturing a back-emitting device. The following synthesis example and examples are only used to illustrate the present invention, and the scope of the present invention is not limited to the following examples.

[0106] Synthesis Example 1: Synthesis of Compound 3

[0107]

[0108] In a round-bottom flask, 3.0 g of N-phenylnaphthalen-2-amine, 2.7 g of 3,6-dibromo-9-phenyl-9H-carbazole, 2.0 g of t-BuONa, 0.5 g of Pd2(dba)3, and 0.3 ml of (t-Bu)3P were dissolved in 100 ml of toluene and stirred under reflux. The reaction was confirmed by thin layer chromatography (TLC) and terminated by adding water. The organic layer was extracted with MC (methylene chloride) and recrystallized after vacuum filtration to obtain 6.3 g of compound 3. (Yield: 68%)

[0109] m / z: 677.28 (100.0%), 678.29 (54.5%), 679.29 (14.6%), 680.29 (2.6%), 678.28 (1.1%)

[0110] Synthesis Example 2: Synthesis of Compound 13

[0111]

[0112] Compound 13 was synthesized by the same method as in Synthesis Example 1, using diphenylamine and 3,6-dibromo-9-(naphthalen-2-yl)-9H-carbazole instead of N-phenylnaphthalen-2-amine and 3,6-dibromo-9-phenyl-9H-carbazole. (Yield: 65%)

[0113] m / z: 627.27 (100.0%), 628.27 (50.1%), 629.27 (12.7%), 630.28 (2.0%), 628.26 (1.1%)

[0114] Synthesis Example 3: Synthesis of Compound 25

[0115]

[0116] Compound 25 was synthesized by the same method as in Synthesis Example 1, using N-phenylpyridin-2-amine instead of N-phenylnaphthalen-2-amine. (Yield: 59%)

[0117] m / z: 579.24 (100.0%), 580.25 (43.6%), 581.25 (9.3%), 580.24 (1.8%), 582.25 (1.4%)

[0118] Synthesis Example 4: Synthesis of Compound 34

[0119]

[0120] Compound 34 was synthesized by the same method as in Synthesis Example 1, using N-phenylquinolin-8-amine instead of N-phenylnaphthalen-2-amine. (Yield: 63%)

[0121] m / z: 679.27 (100.0%), 680.28 (52.3%), 681.28 (13.4%), 682.28 (2.4%), 680.27 (1.8%)

[0122] Synthesis Example 5: Synthesis of Compound 63

[0123]

[0124] Compound 63 was synthesized by the same method as in Synthesis Example 1, using 2,8-dibromodibenzo[b,d]furan instead of 3,6-dibromo-9-phenyl-9H-carbazole (yield: 60%).

[0125] m / z: 602.24(100.0%), 603.24(48.0%), 604.24(11.6%), 605.25(1.7%)

[0126] Synthesis Example 6: Synthesis of Compound 145

[0127]

[0128] Compound 145 was synthesized by the same method as in Synthesis Example 1, using diphenylamine instead of N-phenylnaphthalen-2-amine and 2,7-dibromo-9-phenyl-9H-carbazole instead of 3,6-dibromo-9-phenyl-9H-carbazole. (Yield: 58%)

[0129] m / z: 577.25 (100.0%), 578.26 (45.8%), 579.26 (10.2%), 580.26 (1.6%), 578.25 (1.1%)

[0130] Manufacturing of back-emitting elements

[0131] According to Figure 1 The structure shown here produces a back-emitting element. The back-emitting element is stacked in the following order: 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, from bottom to top.

[0132] The compounds used in the organic layer located inside the electrode of the back-light emitting device of the present invention are shown in Table 1 below.

[0133]

Table 1

[0134]

[0135] Example 1

[0136] A hole injection layer is formed on the indium tin oxide (ITO) substrate. HI01 HATCN and as a hole transport layer HT01, then doped with BH01:BD01 3% to form a film Next, a film is formed as an electron transport layer. ET01:Liq (1:1) was deposited LiF is deposited to form an electron injection layer. A thickness of Al is deposited on the reflective electrode (cathode) to form a reflective electrode protection layer. The thickness of the compound 3 prepared in Synthesis Example 1 was 0.5 Å. The device was encapsulated in a glove box to produce a back-emitting device.

[0137] Example 2 to Example 6

[0138] The same method as in Example 1 was used to produce a back-emitting device, except that the compounds produced in Synthesis Examples 2 to 6 were used to form a film to form a reflective electrode protective layer.

[0139] Example 7

[0140] The same method as in Example 1 was used to manufacture the reflective electrode protective layer. A back-light emitting device was manufactured using Compound 3 manufactured in Synthesis Example 1 with a thickness of 1000 nm.

[0141] Example 8

[0142] The same method as in Example 1 was used to manufacture the reflective electrode protective layer. A back-light emitting device was manufactured using Compound 3 manufactured in Synthesis Example 1 with a thickness of 1000 nm.

[0143] Comparative Example 1 and Comparative Example 2

[0144] In the same manner as in Example 1, a reflective electrode protective layer was formed by forming a film using Comparative Compound 1 (Ref. 1) and Comparative Compound 2 (Ref. 2) shown in Table 2 below, thereby producing a back-emitting device.

[0145]

Table 2

[0146]

[0147] Comparative Example 3: Fabrication of a front-emitting element

[0148] A hole injection layer was formed on an indium tin oxide (ITO) substrate having a reflective layer containing Ag. HI01 HATCN and as a hole transport layer HT01, then doped with BH01:BD013% to form a film Next, a film is formed as an electron transport layer. ET01:Liq (1:1) was deposited Next, MgAg was deposited to a thickness of 15 nm as a transparent electrode (cathode), and then Comparative Compound 1 (Ref. 1) was deposited to a thickness of 15 nm as a light efficiency improvement layer on top of the cathode. The front-emitting element was manufactured by encapsulating the element in a glove box.

[0149] Component performance evaluation

[0150] By applying voltage to a Keithley 2400 source measurement unit to inject electrons and holes, and measuring the brightness of the emitted light using a Konica Minolta spectroradiometer (CS-2000), the performance of the elements of Examples 1 to 8 and Comparative Examples 1 to 3, namely, the current density and brightness relative to the applied voltage, were evaluated under atmospheric pressure conditions. The results are shown in Table 3 below.

[0151]

Table 3

[0152] Op.V <![CDATA[mA / cm 2 ]]> Cd / A LT50 Example 1 3.5 10 8.5 1130 Example 2 3.5 10 8.5 1120 Example 3 3.5 10 8.5 1150 Example 4 3.5 10 8.5 1140 Example 5 3.5 10 8.5 1110 Example 6 3.5 10 8.5 1050 Example 7 3.5 10 8.5 1350 Example 8 3.5 10 8.5 1340 Comparative Example 1 3.5 10 8.5 800 Comparative Example 2 3.5 10 8.5 700 Comparative Example 3 3.6 10 4.8 550

[0153] It can be found that compared with Comparative Examples 1 and 2, the compound of the present invention uses two aromatic amine structures connected by a three-ring condensed group having a five-membered ring, so bubbles and recrystallization will not form on the upper end and side characteristics of the deposition, thereby stably forming a thin film. Thereby, the stability of the element under oxygen, moisture and external pollution can be effectively improved, and the service life can be significantly improved. In addition, it can be found that the back-light emitting structure of the present invention uses a reflective electrode to protect it and increase its service life. The electrode protection layer with the thickness above is suitable, but in the front light emitting structure shown in Comparative Example 3, the stacked When a light efficiency improvement layer with a certain thickness is added, the efficiency and service life will be significantly reduced. That is, in order to fully achieve the role of the electrode protection layer in the front light emitting structure, when a certain thickness is stacked, the transmittance will be significantly reduced and the light extraction efficiency will be reduced, which will eventually lead to the destruction of the element balance and the reduction of service life. In addition, by comparing Example 7 and Example 8, it can be found that specifically in The service life can be further improved even in stacked Above the thickness, the service life improvement effect proportional to the thickness will not be shown. The thickness range can reduce the consumption of protective film materials and achieve commercialization more effectively.

[0154] Film uniformity measurement

[0155] 3 g of each of Comparative Compound 1 (Ref. 1), Comparative Compound 2 (Ref. 2), Compound 34, and Compound 25 were vacuum deposited on a glass substrate, and then heat-treated at 100°C for 30 minutes. The top and side surfaces were then measured using a scanning electron microscope (SEM, Hitachi, SU8010). Figure 2 It can be found that compared with the comparative example, the compound of the present invention forms a uniform film on both the upper end and the side, indicating that a stable film can be effectively formed. Although not shown, other compounds proposed in the preparation examples of the present invention can also form a uniform film.

Claims

1. A back-emitting element, characterized in that: Include: a first electrode and a second reflective electrode; One or more organic layers are interposed between the first electrode and the second reflective electrode; and The reflective electrode protection layer is arranged outside the second reflective electrode and contains a compound for the reflective electrode protection layer. The compound for the reflective electrode protective layer is represented by the following chemical formula 1: Chemical formula 1 In the chemical formula 1, X is NAr, O, S, or CRR, Ar, Ar1 to Ar4 are each independently an aryl group having three or fewer rings, or a heteroaryl group having three or fewer rings, L1 and L2 are each independently a direct bond, a phenylene group or a pyridylene group, R and R' are each independently hydrogen, deuterium, C1 alkyl, or C6 aryl, and R and R' may or may not form a ring by combining with each other. R1 and R2 are each independently hydrogen or deuterium, l and m are each independently an integer from 0 to 3.

2. The back-light emitting element according to claim 1, Ar, Ar1 to Ar4 are each independently a monocyclic aryl group, a monocyclic heteroaryl group, a condensed bicyclic aryl group, or a condensed bicyclic heteroaryl group.

3. The back-light emitting element according to claim 1, Two or more of Ar, Ar1 to Ar4 are each independently a heteroaryl group having three or fewer rings and containing nitrogen.

4. The back-light emitting element according to claim 1, Ar, Ar1 to Ar4 are each independently phenyl, biphenyl, pyridyl, phenylpyridyl, quinolyl, naphthyl or phenanthrenyl.

5. The back-light emitting element according to claim 1, Ar1 and Ar2, and Ar3 and Ar4 are respectively the same as each other.

6. The back-light emitting element according to claim 1, The X is NAr or O.

7. The back-light emitting element according to claim 1, The chemical formula 1 is represented by the following chemical formula 2: Chemical formula 2 In the chemical formula 2, The definitions of Ar, Ar1 to Ar4 are the same as those in Chemical Formula 1.

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

9. The back-light emitting element according to claim 1, The thickness of the reflective electrode protection layer is 2500 to 10. The back-light emitting element according to claim 1, The organic layer has a structure in which two or more light-emitting layers are stacked.

11. The back-light emitting element according to claim 1, A second protective layer is further provided on the outer side of the reflective electrode protective layer.

12. The back-light emitting element according to claim 11, The second protective layer includes silicon nitride or silicon oxide.

Images