A phosphorescent doping material with pyridyl azadibenzofuran ligand and its application

Abstract

The present invention provides a phosphorescent doping material with a pyridyl azadibenzofuran ligand and an application thereof, belonging to the technical field of organic electroluminescent diodes. The phosphorescent doping material with a pyridyl azadibenzofuran ligand of the present invention uses metal iridium as a structural core, phenylpyridine as a main ligand, and pyridyl azadibenzofuran as an auxiliary ligand, has a higher decomposition temperature, a lower JNCD value, and exhibits the technical effects of high luminous efficiency, long life, and low driving voltage in the device.

Description

Technical Field

[0001] The invention belongs to the technical field of organic electroluminescent diodes and relates to a phosphorescent doping material with a pyridyl azadibenzofuran ligand and an application thereof. Background Art

[0002] OLED is a light-emitting device with double hole and electron injection, which directly converts electrical energy into light energy of organic semiconductor material molecules. Compared with traditional display devices such as CRT, LCD, PDP, OLED has high brightness, high contrast, high definition, wide viewing angle, and wide color gamut to achieve high-quality images. It also has unique characteristics of OLED display such as low driving voltage, low power consumption, self-luminescence, high luminous efficiency, and short response time. Therefore, OLED has been widely researched, developed, and used.

[0003] As phosphorescent materials, precious metal complexes make full use of singlet and triplet excitons. Compared with fluorescent materials that only use singlet excitons, the effective utilization of triplet excitons, which accounts for up to 75%, enables PhOLED (phosphorescent organic light-emitting device) based on phosphorescent materials to achieve 100% internal quantum efficiency. In recent years, phosphorescent materials have gradually replaced traditional fluorescent materials and become a research hotspot for OLED luminescent materials. Among them, iridium complexes are the most studied and most promising type of phosphorescent materials because of their short triplet lifetime and good luminescence properties. The green phosphorescent material with iridium as the core is the earliest material studied. Ir(ppy)3 is the earliest green phosphorescent material proposed by the Thompson and Forrest team.

[0004] However, the current phosphorescent materials still have the following disadvantages: due to the presence of coordination bonds, the thermal stability of the materials is poor, especially when the device is working for a long time, the materials are prone to decomposition, resulting in reduced efficiency and life of the device. Therefore, it is a technical problem that people in this field need to solve urgently to develop a high-performance phosphorescent material that enables organic electroluminescent devices to have comprehensive characteristics such as high efficiency, long life and low voltage. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a phosphorescent doping material having a pyridyl azadibenzofuran ligand and its application. The phosphorescent doping material of the present invention uses phenylpyridine as the main ligand and pyridyl azadibenzofuran as the auxiliary ligand, has a higher decomposition temperature, a lower JNCD (color accuracy) value, and exhibits the technical effects of high luminous efficiency, long life, and low driving voltage in the device.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] In one aspect, the present invention provides a phosphorescent dopant material having a pyridyl azadibenzofuran ligand, wherein the phosphorescent dopant material having a pyridyl azadibenzofuran ligand has a structure shown in Formula I:

[0008]

[0009] Among them, R1-R 16 independently selected from hydrogen, deuterium, halogen, cyano, substituted or unsubstituted C1-C20 alkyl, substituted or unsubstituted C3-C20 cycloalkyl, substituted or unsubstituted C6-C30 aryl, substituted or unsubstituted C4-C30 heteroaryl, and the substituent is selected from any one or a combination of at least two of deuterium, halogen, cyano, C1-C10 alkyl, C1-C10 alkoxy, C6-C20 aryl, and C4-C20 heteroaryl.

[0010] In the present invention, R1-R 16 The group may be partially deuterated, fully deuterated, or undeuterated.

[0011] In the present invention, the range of the number of carbon atoms of each group is limited, which means that the number of carbon atoms of the group can be any integer in the limited range, for example, C1-C20 means that the number of carbon atoms can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20, and C6-C30 means that the number of carbon atoms can be 6, 8, 10, 12, 15, 18, 20, 23, 25, 28 or 30, and so on.

[0012] In the present invention, the halogen is F, Cl, Br or I.

[0013] Preferably, the R1-R 16 independently selected from hydrogen, deuterium, fluorine, cyano, methyl, ethyl, propyl, n-propyl, isopropyl, butyl, n-butyl, isobutyl, tert-butyl, sec-butyl, 1-methyl-butyl, 1-ethyl-butyl, pentyl, n-pentyl, isopentyl, neopentyl, tert-pentyl, hexyl, n-hexyl, 1-methylpentyl, 2-methylpentyl, 4-methyl-2-pentyl, 3,3-dimethylbutyl, heptyl, n-heptyl, 1-methylhexyl, cyclopentyl methyl, cyclohexylmethyl, octyl, n-octyl, tert-octyl, 1-methylheptyl, 2-ethylhexyl, 2-propylpentyl, n-nonyl, 2,2-dimethylheptyl, 1-ethyl-propyl, 1,1-dimethyl-propyl, isohexyl, 4-methylhexyl, 5-methylhexyl, -CD3, -CF3, -CD2-CD3, -C(CD3)3, -CD2-CD2-CD3, -CH2-CD3, * indicates the position where the substituent is attached.

[0014] Preferably, R1-R 16 Independently selected from cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, 3-methylcyclopentyl, 3-methylcyclohexyl, 4-methylcyclohexyl, 2,3-dimethylcyclohexyl, 3,4,5-trimethylcyclohexyl, 4-tert-butylcyclohexyl, cycloheptyl, cyclooctyl, 2,3-dimethylcyclopentyl, bicyclo[3.1.1]heptyl, and adamantyl.

[0015] Preferably, R1-R 16 The radicals are independently selected from phenyl, biphenyl, terphenyl, naphthyl, phenanthrenyl, anthracenyl, pyrenyl, spirobifluorenyl, 9,9-dimethylfluorenyl, diphenylfluorenyl, peryl, indenyl, azulenyl, triphenylenyl, methylphenyl, ethylphenyl, methoxyphenyl, phenylnaphthyl or cyanophenyl.

[0016] Preferably, R1-R 16 independently selected from pyrrolyl, furanyl, oxazolyl, isoxazolyl, thienyl, thiazolyl, isothiazolyl, thiadiazolyl, oxadiazolyl, imidazolyl, pyrazolyl, triazole, pyridazinyl, pyrazinyl, pyridinyl, pyrimidinyl, triazinyl, indolyl, quinolyl, isoquinolyl, acridinyl, benzofuranyl, anisole, benzothiophenyl, benzimidazolyl, benzothiazolyl, benzotriazolyl, benzoxadiazolyl, benzoxazolyl, cinnoline, quinoxalinyl, dibenzofuranyl, dibenzothiophenyl, phenylpyridinyl, phenylcarbazolyl, carbazolyl, phenanthrolinyl, indolizinyl, naphthyridinyl, phenylpyridinyl, phenylpyrimidinyl, phthalazinyl, 9,9-dimethylxanthenyl or 9-phenyl-9h-carbazolyl.

[0017] Preferably, the phosphorescent doping material having a pyridyl azadibenzofuran ligand has a structure shown in Formula Ia to Formula Ic:

[0018]

[0019] in,

[0020] R2, R3, R5 and R7 are consistent with the scope defined in Formula I, but are not hydrogen at the same time;

[0021] R 10 , R 11 and R 13 The range is consistent with that defined in Formula I, but not hydrogen.

[0022] Preferably, the phosphorescent doping material having a pyridyl azadibenzofuran ligand has a structure shown in Formula Ic, wherein R2, R3, R5, R7, R 10 , R 11 and R 13 The range is consistent with that defined in Formula I, but all are not hydrogen.

[0023] Preferably, the phosphorescent doping material having a pyridyl azadibenzofuran ligand is selected from any one of the following complexes:

[0024]

[0025]

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041] In the present invention, the synthesis route of the phosphorescent doping material having a pyridyl azadibenzofuran ligand is as follows: reactant AI and reactant BI react to obtain a phosphorescent doping material having a pyridyl azadibenzofuran ligand as shown in general formula I, and the reaction formula is as follows:

[0042]

[0043] R1-R 16 The same as the scope defined in the above general formula I;

[0044] Add reactant AI (1.0 eq) and reactant BI (2.0-4.0 eq, for example, 2.0 eq, 2.5 eq, 2.8 eq, 3 eq, 3.5 eq, 3.8 eq or 4.0 eq) into a reaction flask, add ethanol, and reflux under nitrogen for 24-36 hours (for example, 24 hours, 28 hours, 30 hours, 35 hours or 36 hours). Solid precipitates during the reaction. After the reaction is completed, cool the mixture and filter it with diatomaceous earth. Purify the remaining substance by column chromatography with the eluent having a volume ratio of petroleum ether: dichloromethane of (2-6):1. Dry the solid to obtain a compound of formula I.

[0045] On the other hand, the present invention provides an organic electroluminescent device, comprising an anode, a cathode and an organic thin film layer disposed between the anode and the cathode, wherein the organic thin film layer comprises the phosphorescent doping material having a pyridylazadibenzofuran ligand as described above.

[0046] Preferably, the organic thin film layer comprises a light-emitting layer, the light-emitting layer comprises a host material and a doping material, and the doping material comprises the phosphorescent doping material having a pyridylazadibenzofuran ligand as described above.

[0047] Preferably, the mass percentage content of the doping material in the light-emitting layer is 0.5-10%, for example, 0.5%, 0.8%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10%.

[0048] Regarding the phosphorescent doping material having a pyridyl azadibenzofuran ligand represented by the above formula I, when manufacturing an organic light-emitting element, a vacuum evaporation method or a solution coating method can be used to form an organic layer. The so-called solution coating method refers to spin coating, dip coating, blade coating, inkjet printing, screen printing, spraying, roller coating, etc., but is not limited thereto.

[0049] The phosphorescent doping material having a pyridyl azadibenzofuran ligand represented by Formula I of the present invention is a green light doping material.

[0050] The organic light emitting device of the present invention may be a top emission type, a bottom emission type or a bidirectional emission type according to the materials used.

[0051] Preferably, the organic thin film layer further comprises any one layer or a combination of at least two layers of a hole injection layer, a hole transport layer, a hole transport auxiliary layer, an electron blocking layer, a luminescence auxiliary layer, a hole blocking layer, an electron transport layer or an electron injection layer.

[0052] The light-emitting material of the light-emitting layer is a material that can receive holes and electrons from the hole transport layer and the electron transport layer, respectively, and combine them to emit light in the visible light region.

[0053] Preferably, the host material in the light-emitting layer is a green light single host material or a green light double host material.

[0054] In the present invention, the main material of the light-emitting layer is preferably an aromatic fused ring derivative, a pentacene derivative, a carbazole derivative, a dibenzofuran derivative or a pyrimidine derivative, etc. Specifically, the green light main material of the present invention is selected from but not limited to the following compounds:

[0055]

[0056] The hole injection layer is preferably a p-doped hole injection layer, which means a hole injection layer doped with a p-dopant. The p-dopant is a material that can impart p-type semiconductor characteristics. The p-type semiconductor characteristics mean the characteristics of injecting holes or transporting holes at the HOMO energy level, that is, the characteristics of a material with high hole conductivity.

[0057] P dopants include but are not limited to the following compounds:

[0058]

[0059] A hole transport layer, a hole transport auxiliary layer, an electron blocking layer, a light emitting auxiliary layer, etc. are placed between the anode and the light emitting layer, and they can be used to promote hole injection and / or hole transport, or to prevent electron overflow.

[0060] In the present invention, the material of the hole transport layer, hole transport auxiliary layer, electron blocking layer or luminescent auxiliary layer can be selected from aromatic amine derivatives, conductive polymers, and block copolymers having both conjugated and non-conjugated parts. Specifically, the material of the hole transport layer, hole transport auxiliary layer, electron blocking layer or luminescent auxiliary layer is selected from but not limited to the following compounds:

[0061]

[0062]

[0063] The electron transport region may include at least one of an electron buffer layer, a hole blocking layer, an electron transport layer, and an electron injection layer, and preferably at least one of an electron transport layer and an electron injection layer. The electron transport region is a layer that can improve the problem of degradation of luminous brightness due to changes in current characteristics in the device when the device is exposed to high temperature during the process of manufacturing the panel, and it can control charge flow characteristics.

[0064] The material of the electron transport layer (or hole blocking layer) can be a derivative of oxazole, imidazole, thiazole or triazine, a metal chelate, a quinoline derivative, an oxaline derivative, a diazanthracene derivative, a diazanthracene derivative, a silicon-containing heterocyclic compound, a perfluorinated oligomer, etc.; specifically, the electron transport layer material is selected from but not limited to the following compounds:

[0065]

[0066]

[0067] In the present invention, the material of the electron injection layer includes oxazole, oxadiazole, triazole, imidazole, perylenetetracarboxylic acid, fluorenyl methane, anthrone and their derivatives, magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin, ytterbium and other metals or their alloys, metal complexes or nitrogen-containing 5-membered ring derivatives, etc., but is not limited thereto.

[0068] The cathode material is usually a material with a small work function in order to facilitate the injection of electrons into the organic layer. Specific examples of cathode materials include metals such as magnesium, calcium, sodium, potassium, titanium, indium, yttrium, lithium, gadolinium, aluminum, silver, tin and lead, or their alloys: multilayer structures such as LiF / Al or LiO2 / Al, Mg / Ag, etc.

[0069] As the anode material, in order to enable holes to be smoothly injected into the organic layer, a material with a large work function is preferably used. Specific examples of the anode material that can be used in the present invention include metals such as vanadium, chromium, copper, zinc, gold, or their alloys; metal oxides such as zinc oxide, indium oxide, indium tin oxide (ITO), indium zinc oxide (IZO); combinations of metals and oxides such as ZnO:Al or SnO2:Sb; conductive polymers such as polypyrrole and polyaniline, etc.

[0070] Except that the doping material disclosed herein is the compound of Formula I, there is no particular limitation on other layer materials in the OLED device. Existing hole injection materials, hole transport materials, dopant materials, hole blocking layer materials, electron transport layer materials and electron injection materials can be used.

[0071] In another aspect, the present invention provides a display panel, comprising the organic electroluminescent device as described above.

[0072] The display panels described in the present invention include but are not limited to flat panel displays, computer monitors, medical monitors, televisions, billboards, lights for internal or external lighting and / or signals, head-up displays, fully transparent or partially transparent displays, flexible displays, laser printers, telephones, mobile phones, photo albums, personal digital assistants (PDAs), wearable devices, laptops, digital cameras, camcorders, viewfinders, microdisplays, three-dimensional displays, virtual reality or augmented reality displays, vehicles, video walls including multiple displays tiled together, theater or venue screens, light therapy devices and signs, etc.

[0073] Compared with the prior art, the present invention has the following beneficial effects:

[0074] The phosphorescent doping material with pyridylazadibenzofuran ligand of the present invention uses metal iridium as the structural core, phenylpyridine as the main ligand, and pyridylazadibenzofuran as the auxiliary ligand, has a higher decomposition temperature and a lower JNCD value, and exhibits the technical effects of high luminous efficiency, long life, and low driving voltage in the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of compound 3;

[0076] Figure 2 is the hydrogen NMR spectrum of compound 271. DETAILED DESCRIPTION

[0077] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0078] Reactants A-3, A-135, A-249, A-271, and A-343 belong to the prior art and can be prepared according to the prior art scheme. In brief, the corresponding first ligand compound can be reacted with iridium trichloride trihydrate to obtain an intermediate; the intermediate is subjected to a ligand replacement reaction of the metal ligand compound with silver trifluoromethanesulfonate and methanol to obtain a reactant.

[0079] Example 1: Synthesis of Compound 3

[0080]

[0081] Reactant A-3: CAS 1621396-13-1

[0082] Reactant B-3: CAS 2709029-96-7

[0083] Reactant A-3 (20 mmol) and reactant B-3 (50.0 mmol) were added to a reaction flask, and 500 mL of ethanol was added. The mixture was refluxed for 24 hours under nitrogen protection. Solids were precipitated during the reaction. After the reaction was completed, the mixture was cooled and filtered with diatomaceous earth. The obtained solid was purified by column chromatography. The eluent ratio was petroleum ether: dichloromethane = 3:1. The obtained solid was dried to obtain compound 3 (6.56 g, yield: 42%, test value MS (ESI, m / Z): [M+H] + =781.15).

[0084] The H NMR spectrum of compound 3 is as follows Figure 1 shown.

[0085] HPLC purity: >99%.

[0086] Elemental Analysis:

[0087] Theoretical values: C, 59.98; H, 4.39; Ir, 24.61; N, 8.97; O, 2.05

[0088] Test values: C, 59.94; H, 4.44; Ir, 24.60; N, 8.99; O, 2.09.

[0089] Example 2: Synthesis of Compound 135

[0090]

[0091] Reactant A-135: CAS 2245340-35-4

[0092] Reactant A-135 (20 mmol) and reactant B-135 (60.0 mmol) were added to a reaction bottle, and 500 mL of ethanol was added. The mixture was refluxed for 24 hours under nitrogen protection. Solids were precipitated during the reaction. After the reaction was completed, the mixture was cooled and filtered with diatomaceous earth. The solid was purified by column chromatography with the eluent ratio of petroleum ether: dichloromethane = 3:1. The solid was dried to obtain compound 135. (5.80 g, yield: 29%, test value MS (ESI, m / Z): [M+H] + =1001.56).

[0093] HPLC purity: >98%.

[0094] Elemental Analysis:

[0095] Theoretical values: C, 65.97; H, 6.24; Ir, 19.20; N, 6.99; O, 1.60

[0096] Test values: C, 65.81; H, 6.39; Ir, 19.22; N, 7.03; O, 1.63.

[0097] Example 3: Synthesis of Compound 249

[0098]

[0099] Reactant A-249: CAS 1532554-40-7

[0100] Reactant B-249: CAS 2709030-45-3

[0101] Reactant A-249 (20 mmol) and reactant B-249 (70 mmol) were added to a reaction bottle, and 500 mL of ethanol was added. The mixture was refluxed for 24 hours under nitrogen protection. Solids were precipitated during the reaction. After the reaction was completed, the mixture was cooled and filtered with diatomaceous earth. The solids were purified by column chromatography. The eluent ratio was petroleum ether: dichloromethane = 3:1. The solids were dried to obtain compound 249. (3.40 g, yield: 20%, test value MS (ESI, m / Z): [M+H] + =851.32).

[0102] HPLC purity: >98.0%.

[0103] Elemental Analysis:

[0104] Theoretical values: C, 63.51; H, 3.79; Ir, 22.59; N, 8.23; O, 1.88

[0105] Test values: C, 63.41; H, 3.88; Ir, 22.56; N, 8.28; O, 1.92.

[0106] Example 4: Synthesis of Compound 271

[0107]

[0108] Reactant A-271: CAS 2135569-36-5

[0109] Reactant B-271: CAS 2709030-27-1

[0110] Reactant A-271 (20 mmol) and reactant B-271 (60.0 mmol) were added to a reaction bottle, and 500 mL of ethanol was added. The mixture was refluxed for 24 hours under nitrogen protection. Solids were precipitated during the reaction. After the reaction was completed, the mixture was cooled and filtered with diatomaceous earth. The obtained solid was purified by column chromatography. The eluent ratio was petroleum ether: dichloromethane = 3:1. The obtained solid was dried to obtain compound 271 (4.75 g, yield: 30%, test value MS (ESI, m / Z): [M+H] + =792.28).

[0111] The H NMR spectrum of compound 271 is as follows Figure 2 shown.

[0112] HPLC purity: >99%.

[0113] Elemental Analysis:

[0114] Theoretical values: C, 60.67; H, 4.20; Ir, 24.27; N, 8.84; O, 2.02

[0115] Test values: C, 60.52; H, 4.33; Ir, 24.30; N, 8.88; O, 2.05.

[0116] Example 5: Synthesis of Compound 343

[0117]

[0118] Reactant A-343: CAS 1795515-71-7

[0119] Reactant A-343 (20 mmol) and reactant B-343 (60.0 mmol) were added to a reaction bottle, and 500 mL of ethanol was added. The mixture was refluxed for 24 hours under nitrogen protection. Solids were precipitated during the reaction. After the reaction was completed, the mixture was cooled and filtered with diatomaceous earth. The obtained solid was purified by column chromatography with the eluent ratio of petroleum ether: dichloromethane = 3:1. The obtained solid was dried to obtain compound 343 (6.13 g, yield: 35%, test value MS (ESI, m / Z): [M+H] + =876.34).

[0120] HPLC purity: >99%.

[0121] Elemental Analysis:

[0122] Theoretical values: C, 63.06; H, 5.18; Ir, 21.94; N, 7.99; O, 1.83

[0123] Test values: C, 92.92; H, 5.30; Ir, 21.96; N, 8.02; O, 1.85.

[0124] Example 6-32

[0125] The following compounds were synthesized by referring to the synthesis methods of Examples 1 to 5. Their molecular formulas and mass spectra are shown in Table 1. The mass spectrometer model was Waters XEVO TQD with low precision and the test was performed using an ESI source.

[0126] Table 1 Molecular formula and mass spectrum

[0127]

[0128]

[0129] The structural formula of the comparative compound 1-12 used in the present invention is as follows:

[0130]

[0131] The decomposition temperature (Td) of the compounds of the present invention and the comparative compounds was tested. The thermal weight loss temperature Td is the temperature at which the weight loss is 1% in a nitrogen atmosphere. The test was performed on a TGA-50H thermogravimetric analyzer of Shimadzu Corporation, Japan. The results are shown in Table 2 below:

[0132] Table 2

[0133]

[0134]

[0135] It can be seen from the data in Table 2 above that compared with the comparative compounds, the compounds of the present application have a higher decomposition temperature, can inhibit the crystallization of the material and improve the intermolecular stacking effect, avoid carrier accumulation traps, improve the carrier balance of the device, inhibit the decomposition of the material at high brightness, and increase the device service life.

[0136] Application Example 1 Preparation of green organic electroluminescent device:

[0137] A method for preparing a green organic electroluminescent device comprises the following steps:

[0138] a. ITO anode: wash an ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 150nm in distilled water twice, ultrasonically wash for 30 minutes, and then repeatedly wash it with distilled water twice, ultrasonically wash for 10 minutes, and bake it in a vacuum oven at 220°C for 2 hours. After baking, cool it down and it can be used; use the substrate as the anode, use an evaporation machine to carry out the evaporation device process, and evaporate other functional layers on it in sequence;

[0139] b. HIL (hole injection layer): The evaporation rate of the hole injection layer is HT1-10 and P-5, and the chemical formula thereof is shown below; the evaporation rate ratio of HT1-10 and P-5 is 97:3, and the thickness is 10 nm;

[0140] c. HTL (hole transport layer): At a deposition rate of 100%, 120 nm of HT1-10 was vacuum-deposited on the hole injection layer as a hole transport layer.

[0141] d. Prime (luminous auxiliary layer): At a deposition rate of , 45nm of HT1-24 was vacuum-deposited on the hole transport layer as a light-emitting auxiliary layer;

[0142] e. EML (light-emitting layer): Then on the above-mentioned light-emitting auxiliary layer, The evaporation rate is 40 nm, and the main material (Host) and the compound 1 of the present invention as the dopant material (Dopant) of the light-emitting layer are vacuum-evaporated with a total thickness of 40 nm. GH-5 and GH-2 are co-evaporated as dual main materials and dopant materials. The ratio of GH-5 to GH-2 is 50%:50%, and the evaporation rate ratio of the main material to the Dopant is 88:12.

[0143] f. HBL (hole blocking layer): The evaporation rate is 5.0 nm, and the hole blocking layer ET-15 is vacuum-deposited.

[0144] g. ETL (Electron Transport Layer): ET-5 and Liq were vacuum-deposited at a deposition rate of 30 nm as an electron transport layer; the deposition rate ratio of ET-5 to Liq was 1:1;

[0145] h. EIL (electron injection layer): The evaporation rate is 1.0 nm, and a Yb film layer is evaporated to form an electron injection layer;

[0146] i. Cathode: 18 nm of magnesium and silver were evaporated at a deposition rate ratio of 1:9 to form a cathode;

[0147] j. Light extraction layer: At a deposition rate of , CPL with a thickness of 70 nm was vacuum-deposited on the cathode as a light extraction layer;

[0148] k. Package the vapor-deposited substrate; first, use the glue coating equipment to coat the cleaned cover with UV glue, then move the coated cover to the pressing section, place the vapor-deposited substrate on the upper end of the cover, and finally bond the substrate and the cover with the bonding equipment, and complete the light curing of the UV glue at the same time.

[0149] The green light device structure is as follows:

[0150] ITO / Ag / ITO / HT1-10:P-5(10nm) / HT1-10(125nm) / HT1-24(45nm) / (GH-5+GH-2):Compound of formula I (40nm) / ET-15(5nm) / ET-5:Liq(30nm) / Yb(1nm) / Mg:Ag(18nm) / CPL(70nm).

[0151] The material structures involved in device preparation are as follows:

[0152]

[0153] Application Example 2-62

[0154] The organic electroluminescent devices of Application Examples 2-62 were prepared according to the above-mentioned method for preparing an organic electroluminescent device, except that Compound 1 in Application Example 1 was replaced by the corresponding compounds in Table 3.

[0155] Comparative Application Example 1-Comparative Application Example 12

[0156] An organic electroluminescent device was prepared according to the above method for preparing an organic electroluminescent device, except that the compound 1 in Application Example 1 was replaced by comparative compounds 1-12 respectively.

[0157] The driving voltage, luminous efficiency, lifespan, chromaticity (CIE), and color accuracy (JNCD) of the organic electroluminescent devices obtained in Example 1-62 and Comparative Application Example 1-12 at a brightness of 15000 (nits) were characterized. The test results are shown in Table 3.

[0158] Table 3

[0159]

[0160]

[0161]

[0162] Color accuracy is measured by JNCD (Just Noticeable Color Difference). JNCD reflects the degree of color deviation and is one of the important indicators for measuring screen color accuracy. The smaller the value, the better the screen restores the original color. The current industry standard is JNCD <2.

[0163] It can be seen from Table 3 above that the compound of the present invention uses metal iridium as the structural core, phenylpyridine as the main ligand, and pyridyl azadibenzofuran as the auxiliary ligand, and has a lower JNCD value than the comparative compound in the prior art, showing the technical effects of high luminous efficiency, long life, and low driving voltage.

[0164] The comparative compounds 1-5 of the present invention use phenylpyridine as the main ligand and less than 2 pyridyl azadibenzofuran auxiliary ligands. The auxiliary ligands of the present invention introduce 3 N atoms and have a greater conjugated property. On the one hand, they can improve the stacking effect between molecules, and on the other hand, they can increase the horizontal arrangement of the molecules, so that the molecules can be effectively arranged horizontally, thereby effectively increasing the photon extraction efficiency, improving the viewing angle of the green light device, and greatly improving the device life.

[0165] Among them, compared with comparative compound 1, compound 191 of the present invention is compared with comparative compound 2, compound 254 of the present invention is compared with comparative compound 4, and compound 275 of the present invention is compared with comparative compound 5, there are differences in the number of N contained in the auxiliary ligand. From the results in Table 3, it can be seen that the compounds of the present invention have the technical effects of improving luminous efficiency, extending life, reducing driving voltage, and having a lower JNCD value.

[0166] In order to clearly present the differences between the above compounds, the corresponding compounds are compared together as shown below:

[0167]

[0168] The comparative compound 6-12 of the present invention uses pyridyl azaphenyl as the main ligand. The main ligand of the present invention is phenylpyridine. The function of the main ligand is to regulate the energy level and avoid the loss of energy transfer efficiency by directly transferring holes to the doping material.

[0169] Compared with comparative compound 9, compared with comparative compound 191, compared with comparative compound 10, compared with comparative compound 11, compared with comparative compound 12, the difference between compound 1 of the present invention and comparative compound 191, compound 266 of the present invention and comparative compound 11, and compound 272 of the present invention and comparative compound 12 lies in the difference in the main ligand. It can be seen from the data in Table 3 that the compounds of the present invention have the technical effects of improving luminous efficiency, improving lifespan, reducing driving voltage, and having a lower JNCD value.

[0170] In order to clearly present the differences between the above compounds, the corresponding compounds are compared together as shown below:

[0171]

[0172] Through further analysis of the device results, it was found that there were differences in the improvement of device effects when only the main ligand phenylpyridine had substituents, only the auxiliary ligand pyridylazadibenzofuran had substituents, and when substituents existed on both the main ligand and the auxiliary ligand.

[0173] The compounds with substituents only on the auxiliary ligands have a very significant improvement in device life, extending the life by about 150-200 hours, but the efficiency is basically the same as that of the comparative compound; the compounds of the present invention with substituents only on the main ligands extend the life by about 60-120 hours, the efficiency is generally improved by 2-4%, and the driving voltage is reduced by 0.1-0.15V; when substituents are present on both the main ligand and the auxiliary ligand, the comprehensive performance improvement is stronger and the efficiency improvement is more significant. Compared with the comparative compound, the efficiency is improved by 6-8%, and the life is extended by about 100-160 hours.

[0174] In summary, the performance test results in Table 2 and Table 3 show that the compounds of the present invention have a higher decomposition temperature and a lower JNCD value compared with the prior art, and exhibit the technical effects of high luminous efficiency, long life, and low driving voltage in the device.

[0175] The applicant declares that the present invention uses the above-mentioned embodiments to illustrate the phosphorescent doping material having a pyridyl azadibenzofuran ligand and its application, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A phosphorescent doping material having a pyridyl azadibenzofuran ligand, characterized in that: The phosphorescent doping material having a pyridyl azadibenzofuran ligand has a structure shown in Formula Ic: in, R2, R3, R6 and R7 are not hydrogen at the same time; R 10 , R 11 and R 13 Not at the same time hydrogen; Among them, R2, R3, R6, R7, R 10 , R 11 and R 13 independently selected from hydrogen, fluoro, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, -CD3, -CF3, -CD2-CD3, -C(CD3)3, -CD2-CD2-CD3, -CH2-CD3, Cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, phenyl, biphenyl, terphenyl, naphthyl, methylphenyl, ethylphenyl, methoxyphenyl, phenylnaphthyl, cyanophenyl or pyridyl; * indicates the attachment position of the substituent.

2. A phosphorescent doping material having a pyridyl azadibenzofuran ligand, characterized in that: The phosphorescent doping material having a pyridyl azadibenzofuran ligand is selected from any one of the following complexes:

3. The method for preparing a phosphorescent doping material having a pyridylazadibenzofuran ligand according to claim 1, characterized in that: The preparation method comprises the following steps: Reactant AI reacts with reactant BI to obtain a phosphorescent doping material having a pyridyl azadibenzofuran ligand as shown in Formula Ic, and the reaction formula is as follows: Among them, R2, R3, R6, R7, R 10 , R 11 and R 13 The scope of the invention is the same as that of claim 1.

4. The preparation method according to claim 3, characterized in that: The molar ratio of reactant AI to reactant BI is 1:2.0-4.

0.

5. The preparation method according to claim 3, characterized in that: The reaction was carried out under nitrogen protection.

6. The preparation method according to claim 3, characterized in that: The solvent for the reaction is ethanol.

7. The preparation method according to claim 3, characterized in that: The reaction is carried out under reflux for 24-36 hours.

8. An organic electroluminescent device, characterized in that: The organic electroluminescent device comprises an anode, a cathode and an organic thin film layer arranged between the anode and the cathode; the organic thin film layer is a light-emitting layer, the light-emitting layer comprises a main material and a doping material, and the doping material comprises the phosphorescent doping material having a pyridylazadibenzofuran ligand as claimed in claim 1 or 2.

9. The organic electroluminescent device according to claim 8, characterized in that: The mass percentage content of the doping material in the light-emitting layer is 0.5-10%.

10. A display panel, characterized in that: The display panel comprises the organic electroluminescent device according to claim 8 or 9.

Images