Platinum-based phosphorescent dopant materials, methods of preparation, and organic electroluminescent devices and applications

Abstract

The application discloses a phosphorescent dopant material of a platinum compound, a preparation method, an organic electroluminescent device and application, the phosphorescent dopant material is a platinum compound with a structure shown in chemical formula I, the compound introduces a bicyclic structure on the basis of a parent nucleus, a high conjugated electron distribution system, so that the electron distribution and the excited state can be controlled, and the stability of the material is enhanced. The organic electroluminescent device prepared by adopting the compound as a light-emitting layer dopant material has high luminous efficiency, long service life and the technical effect of improving the driving voltage.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic materials technology, and more specifically, relates to a platinum-based compound phosphorescent doped material, its preparation method, organic electroluminescent device, and its application. Background Technology

[0002] Organic light-emitting diodes (OLEDs) are self-emissive devices that have attracted significant attention in the fields of novel display and lighting technologies due to their advantages such as low driving voltage, high brightness, fast response time, wide viewing angle, high resolution, simple manufacturing process, flexibility, and bendability. For example, OLED display technology has already been applied in smartphones and tablets, and is expected to expand into larger-screen applications such as televisions.

[0003] Organic light-emitting displays (OLEDs) are active-matrix display devices. Currently, small and medium-sized OLED displays have been widely used in high-end smartphones produced by companies such as Huawei, Xiaomi, and Samsung. Achieving the best luminous efficiency of the device under low operating voltage conditions is a common requirement in the OLED field.

[0004] OLED light emission occurs through two main pathways: fluorescence and phosphorescence. Phosphorescence utilizes both singlet and triplet excitons, unlike fluorescent materials which only utilize singlet excitons. The efficient utilization of triplet excitons, up to 75%, theoretically enables phosphorescent OLEDs to achieve 100% internal quantum efficiency. In the past three years, phosphorescent materials have gradually replaced traditional fluorescent materials, becoming a research hotspot in OLED light-emitting materials.

[0005] Currently, luminescent materials are prepared by combining host materials with dopants to improve color purity, luminous efficiency, and stability. Dopants can significantly influence the efficiency and performance of organic light-emitting devices; therefore, developing novel host and dopants that meet practical requirements is crucial. However, due to the complex, time-consuming, and short-lifespan synthesis process of phosphorescent materials, further development of phosphorescent materials is urgently needed. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a platinum-based compound phosphorescent doped material, its preparation method, an organic electroluminescent device, and its application. The green organic electroluminescent device prepared using the platinum-based compound phosphorescent doped material exhibits high luminous efficiency, long lifespan, and improved driving voltage, among other technical advantages.

[0007] To address the above problems, the present invention provides the following technical solution:

[0008] A platinum-based phosphorescent doped material having the compound structure shown in Formula I:

[0009]

[0010] In the formula, R is selected from substituted or unsubstituted C6-C. 30 aryl group; substituted or unsubstituted C6-C 30 The heteroaryl group, wherein the heteroatom is selected from oxygen, nitrogen, and sulfur;

[0011] R1-R3 may be the same as or different from each other, and each is independently selected from hydrogen, deuterium, fluorine, cyano, C1-C 20 Alkyl and C1-C 20 Alkyl group; substituted or unsubstituted C6-C 30 aryl group; substituted or unsubstituted C6-C 30 The heteroaryl group, wherein the heteroatom is selected from oxygen, nitrogen, and sulfur;

[0012] A and B are fused to the benzene ring they belong to, and may be the same as or different from each other. They are each independently selected from hydrogen or any of the following groups. The dashed lines indicate the positions where they are fused to the adjacent benzene ring:

[0013]

[0014] In one embodiment of the present invention, R is selected from one or more of phenyl, biphenyl, terphenyl, naphthyl, furanyl, carbazole, fluorenyl, and pyridyl.

[0015] R1-R3 may be the same as or different from each other, and each is independently selected from one or more of hydrogen, deuterium, fluorine, cyano, methyl, ethyl, isopropyl, tert-butyl, phenyl, naphthyl, biphenyl, terphenyl, furanyl, carbazole, fluorenyl, and pyridyl.

[0016] The "substitution" is monosubstituted, disubstituted, trisubstituted, or tetrasubstituted, and is selected from the following groups: deuterium, fluorine, cyano, and unsubstituted C6-C. 30 aryl; unsubstituted C6-C30 heteroaryl, wherein the heteroatom is selected from oxygen, nitrogen, or sulfur.

[0017] In one embodiment of the present invention, the platinum-based phosphorescent doping material is selected from any one of the following compounds:

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

[0026] The organic electroluminescent compounds of the present invention can be prepared by synthetic methods known to those skilled in the art. For example, they are preferably prepared by the following reaction process.

[0027] Secondly, the present invention also provides a method for synthesizing a platinum-based phosphorescent doped material having the structure shown in the above-described chemical formula I, comprising the following steps:

[0028]

[0029] The specific preparation process includes the following steps:

[0030] a) Under nitrogen atmosphere, raw material A, raw material B, cuprous iodide, 2-pyridinecarboxylic acid, and potassium phosphate were added to a flask, DMSO was added, and the reaction was heated overnight. After cooling to room temperature, a large amount of water was added, the mixture was extracted, the organic phases were combined, evaporated to dryness, and purified by column chromatography to obtain the compound with the structure shown in intermediate 1.

[0031] b) Under nitrogen conditions, intermediate 1, raw material C, Pd(OAc)2, S-Phos, NaOt-Bu, and xylene solution were added to a flask. The reaction was heated and stirred overnight. After cooling to room temperature, the mixture was dried by rotary evaporation and then subjected to column chromatography to obtain the compound with the structure shown in intermediate 2.

[0032] c) Under nitrogen atmosphere, intermediate 2, triethyl formate, and concentrated hydrochloric acid were added to a flask. The reaction was heated to a certain temperature and stirred overnight. The reaction was monitored by TLC until it was completed. The mixture was then cooled to room temperature, dried by rotary evaporation, and the structure of intermediate 3 was obtained by column chromatography.

[0033] d) Under nitrogen atmosphere, intermediate 3, Ag2O, and DCE (dichloroethane) were added to a flask. After the reaction was completed at room temperature, the solvent was evaporated under reduced pressure. Then, (1,5-cyclooctadiene)platinum dichloride (Pt(COD)Cl2) and dichlorobenzene were added. The reaction was heated to a certain temperature and stirred. After the reaction was cooled to room temperature, the compound with the structure shown in formula I was obtained by column chromatography.

[0034] Thirdly, the present invention also provides a green organic electroluminescent device containing a platinum-based phosphorescent doped material having the structure shown in Formula I.

[0035] In one embodiment of the present invention, the green organic electroluminescent device includes a first electrode, a second electrode facing the first electrode, and an organic material layer located between the first electrode and the second electrode; the organic material layer may include a hole transport region, an emissive layer, and an electron transport region; the emissive layer contains a host material and a platinum-based phosphorescent dopant material.

[0036] In one embodiment of the present invention, the main material of the light-emitting layer is a dual-main material, and the evaporation rate ratio of the main material and the doped material is (99-1):(1-99).

[0037] For example, the evaporation rate ratio of the host material to the doped material is 88:12.

[0038] In one embodiment of the present invention, the hole transport region includes at least one of a hole injection layer, a first hole transport layer, a light emission auxiliary layer, a second hole transport layer, and an electron blocking layer; the electron transport region includes at least one of an electron buffer layer, a hole blocking layer, an electron transport layer, and an electron injection layer.

[0039] In one embodiment of the present invention, the organic electroluminescent device further includes an electron injection layer located between the electron transport layer and the cathode.

[0040] In one embodiment of the present invention, the material of the electron injection layer is selected from one or more of LiF, NaCl, CsF, Li2O, Cs2CO3, BaO, Na, Li, and Ca, but is not limited thereto.

[0041] In one embodiment of the present invention, a substrate may be used below the first electrode or above the second electrode.

[0042] Specifically, the substrate can be glass or polymer material with excellent mechanical strength, thermal stability, water resistance, and transparency.

[0043] In one embodiment of the present invention, a thin-film transistor (TFT) may also be incorporated on the substrate used as a display.

[0044] In one embodiment of the present invention, the first electrode can be formed by sputtering or depositing a material used as the first electrode on a substrate.

[0045] In one embodiment of the present invention, when the first electrode is used as the anode, transparent conductive oxide materials such as indium tin oxide (ITO), indium zinc oxide (IZO), tin dioxide (SnO2), and zinc oxide (ZnO) and any combination thereof are used.

[0046] In one embodiment of the invention, the anode material is selected from materials and combinations thereof that facilitate hole injection, in addition to the anode materials listed above, including known materials suitable for use as anodes.

[0047] In one embodiment of the present invention, when the first electrode is used as the cathode, it is preferably made of metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), lithium aluminum (Al-Li), calcium (Ca), magnesium-indium (Mg-In), and magnesium-silver (Mg-Ag), or any combination thereof.

[0048] In addition to the cathode materials listed above, cathode materials can also be materials and combinations thereof that facilitate electron injection, including known materials suitable for use as cathodes.

[0049] In one embodiment of the present invention, the green organic electroluminescent device includes an anode, a hole injection layer, a hole transport layer, a light-emitting auxiliary layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode arranged sequentially; the light-emitting layer contains a host material and a platinum-based phosphorescent dopant material.

[0050] In one embodiment of the present invention, the organic material layer can be formed on the electrode by methods such as vacuum thermal evaporation, spin coating, or printing.

[0051] In one embodiment of the present invention, the compound used as the organic material layer can be a small organic molecule, a large organic molecule, a polymer, or a combination thereof.

[0052] In one embodiment of the present invention, the hole transport region is located between the anode and the light-emitting layer.

[0053] In one embodiment of the present invention, the hole transport region can be a single-layer hole transport layer (HTL), including a single-layer hole transport layer containing only one compound and a single-layer hole transport layer containing multiple compounds, or the hole transport region can be a multilayer structure including at least one of a hole injection layer (HIL), a hole transport layer (HTL), and an electron blocking layer (EBL).

[0054] In one embodiment of the present invention, the material of the hole transport layer may be selected from phthalocyanine derivatives such as CuPc, conductive polymers or polymers containing conductive dopants such as polyphenylene ethylene, polyaniline / dodecylbenzenesulfonic acid (Pani / DBSA), poly(3,4-ethylenedioxythiophene) / poly(4-styrenesulfonate) (PEDOT / PSS), polyaniline / camphorsulfonic acid (Pani / CSA), polyaniline / poly(4-styrenesulfonate) (Pani / PSS), aromatic amine derivatives or any combination thereof.

[0055] Fourthly, the present invention also provides an organic electroluminescent device containing the above-mentioned platinum group compound phosphorescent doping material for use in flat panel displays, computer monitors, medical monitors, televisions, billboards, lamps for internal or external lighting and / or signals, head-up displays, fully transparent or partially transparent displays, flexible displays, laser printers, telephones, mobile phones, tablets, photo albums, personal digital assistants (PDAs), wearable devices, laptops, digital cameras, camcorders, viewfinders, microdisplays, 3D displays, virtual reality or augmented reality displays, vehicles, video walls comprising multiple displays tiled together, theater or stadium screens, phototherapy devices, and signs.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] This invention provides a phosphorescent doping material, which is a platinum group compound with the structure shown in Formula I. This compound introduces a bicyclic structure and a highly conjugated electron distribution system into its core, thus allowing for the control of electron distribution and stable excited states, thereby enhancing the material's stability. Organic electroluminescent devices prepared using this compound as the luminescent layer doping material exhibit high luminous efficiency, long lifetime, and improved driving voltage. Attached Figure Description

[0058] Figure 1 This is the 1H NMR spectrum of compound 9 in Example 1 of the present invention. Detailed Implementation

[0059] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanatory of the present invention, and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0060] Unless otherwise stated, the raw materials and reagents used in the following examples are all commercially available products.

[0061] Example 1

[0062] Step 1) Preparation of raw material B:

[0063]

[0064] S1. Under nitrogen protection, 1.0 eq of B-1 (CAS:2980689-07-2) and 1.1 eq of pinacol diborate were dissolved in 1,4-dioxane solution, and potassium acetate (2.0 eq) and PdCl2 (dppf) (0.05 eq) were added. The mixture was stirred until homogeneous, heated to 110 °C, and refluxed for 10 h. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with ethyl acetate. The organic phases were combined and dried with anhydrous magnesium sulfate. The solvent was removed using a rotary evaporator. The remaining substance was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:4) to obtain intermediate B-1 (yield 69.5%).

[0065] S2. 1.1 eq of intermediate B-1 and 1.0 eq of B-2 (CAS: 59557-92-5) were added to a mixed solution of toluene, ethanol, and water (V:V:V = 2:1:1). The mixture was then purged three times. Under nitrogen protection, potassium carbonate (2.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added, and the mixture was stirred until homogeneous. The mixture was heated to 85°C and refluxed for 8 hours. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water. The organic phase was retained, and the aqueous phase was extracted with ethyl acetate. The organic phases were combined and dried with anhydrous magnesium sulfate. The solvent was removed using a rotary evaporator to obtain a fixed powder, namely the compound shown as intermediate B-2 (yield 75.1%).

[0066] S3. Add 1.0 eq intermediate B-2, 0.1 eq bis(trifluoromethanesulfonyl)imide, and 2.0 eq hexafluoroisopropanol to a dry 100 ml round-bottom flask, add magnetic stirring until completely dissolved, then slowly add 1.3 eq bis(trifluoroacetic acid)iodobenzene over a period of about 5 min. Then stir at room temperature for 0.5 h. After the reaction is complete, separate by column chromatography to obtain the compound shown as intermediate B-3 (yield 61.5%).

[0067] S4. 1.0 eq intermediate B-3 and 1.0 eq starting material B-3 (CAS: 94665-63-1) were dissolved in toluene. Then, under a N2 atmosphere, 0.1 eq of Pd2(dba)3, 0.5 eq of P(t-Bu)3, and 2.0 eq of t-BuONa were added. The mixture was heated to 120 °C and stirred for 12 h. After the reaction was complete, the mixture was filtered hot using diatomaceous earth to remove salts and catalyst. After the filtrate was cooled to room temperature, distilled water was added to the filtrate for washing. The organic phase was separated, and the aqueous phase was extracted with ethyl acetate. The combined organic layers were then dried with magnesium sulfate, and the solvent was removed using a rotary evaporator. Finally, the remaining substances were purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:14) as the eluent to obtain the compound shown in intermediate B-4 (yield: 70.4%).

[0068] S5. Mix the above products 1.0 eq intermediate B-4, 2.0 eq boron tribromide and 200 ml toluene, heat under reflux at 120 °C for 1 h, cool naturally, add 25 ml of 18% hydrochloric acid, cool to obtain a solid, add 5% NaOH solution to dissolve, filter out the insoluble matter, add 18% hydrochloric acid solution again, and precipitate a solid, which is the compound shown in the starting material B, with a yield of 64.3%.

[0069] HPLC purity: >99.7%.

[0070] Mass spectrometry test: Waters XEVO TQD mass spectrometer with ESI source.

[0071] MS(ESI, m / Z): [M+H]+: 410.36

[0072] Step 2) Preparation of compound 9

[0073]

[0074] a) Under nitrogen atmosphere, 1.0 eq of starter B, 1.2 eq of starter A (CAS: 99266-81-6), 0.1 eq of cuprous iodide, 0.2 eq of 2-pyridinecarboxylic acid, and 2.0 eq of potassium phosphate were added to a flask, followed by 200 mL of DMSO. The reaction mixture was heated to 150 °C overnight. After cooling to room temperature, a large amount of water was added, and the mixture was extracted three times with dichloromethane. The organic phases were combined, evaporated to dryness, and purified by column chromatography to obtain the compound with the structure shown in intermediate 1 (yield: 72.5%).

[0075] b) Under nitrogen atmosphere, 1.0 eq of intermediate 1, 1.1 eq of starting material C (CAS: 534-85-0), 0.05 eq of Pd(OAc)2, 1.4 eq of S-Phos, 2.0 eq of NaOt-Bu, and 200 mL of xylene solution were added to a flask. The reaction was heated to 140 °C and stirred overnight. After cooling to room temperature, the mixture was evaporated to dryness and then subjected to column chromatography to obtain the compound with the structure shown in intermediate 2 (yield: 68.3%).

[0076] c) Under nitrogen atmosphere, 1.0 eq intermediate 2, 35 eq triethyl formate, and 0.5 mL concentrated hydrochloric acid were added to a flask. The reaction was heated to 100 °C and stirred overnight. The reaction was monitored by TLC until it was completed. After cooling to room temperature, the mixture was dried by rotary evaporation and then subjected to column chromatography to obtain the compound with the structure shown in intermediate 3 (yield: 69.2%).

[0077] d) Under nitrogen atmosphere, 1.0 eq intermediate 3, 0.6 eq Ag2O, and 20 mL DCE were added to a flask and reacted at room temperature for 12 h. After the reaction was complete, the solvent was evaporated under reduced pressure, and 1.1 eq (1,5-cyclooctadiene)platinum dichloride (Pt(COD)Cl2) was added. After adding 200 mL dichlorobenzene, the reaction was heated to 200 °C and stirred for 24 h. After the reaction was cooled to room temperature, the compound with the structure shown in compound 9 was obtained by column chromatography (yield: 51.6%).

[0078] HPLC purity: >99.7%.

[0079] Mass spectrometry test: Waters XEVO TQD mass spectrometer with ESI source.

[0080] MS (ESI, m / Z): [M+H]+: 871.41.

[0081] Example 2

[0082] Step 1) Preparation of raw material B

[0083]

[0084] S1. Under nitrogen protection, 1.0 eq of B-1-45 (CAS:1259033-32-3) and 1.1 eq of pinacol diborate were dissolved in 1,4-dioxane solution, and potassium acetate (2.0 eq) and PdCl2 (dppf) (0.05 eq) were added. The mixture was stirred until homogeneous, heated to 110 °C, and refluxed for 10 h. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with ethyl acetate. The organic phases were combined and dried with anhydrous magnesium sulfate. The solvent was removed using a rotary evaporator. The remaining substance was purified by column chromatography using a mixed solution of dichloromethane and petroleum ether (V:V = 1:4) to obtain intermediate B-1-45 (yield 71.1%).

[0085] S2. 1.1 eq of intermediate B-1-45 and 1.0 eq of B-2-45 (CAS: 59557-92-5) were added to a mixed solution of toluene, ethanol, and water (V:V:V = 2:1:1). The mixture was then purged three times. Under nitrogen protection, potassium carbonate (2.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added, and the mixture was stirred until homogeneous. The mixture was heated to 85°C and refluxed for 8 hours. After the reaction was completed, the temperature was slightly lowered, and the mixture was filtered with diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature and washed three times with water, retaining the organic phase. The aqueous phase was then extracted with ethyl acetate. The organic phases were combined and dried with anhydrous magnesium sulfate. The solvent was removed using a rotary evaporator to obtain a fixed powder, namely intermediate B-2-45 (yield 70%).

[0086] S3. Add 1.0 eq intermediate B-2-45, 0.1 eq bis(trifluoromethanesulfonyl)imide, and 2.0 eq hexafluoroisopropanol to a dry 100 ml round-bottom flask, add magnetic stirring until completely dissolved, then slowly add 1.3 eq bis(trifluoroacetic acid)iodobenzene over a period of about 5 min. Then stir at room temperature for 0.5 h. After the reaction is complete, separate by column chromatography to obtain intermediate B-3-45 (yield 69.3%).

[0087] S4. 1.0 eq intermediate B-3-45 and 1.0 eq starting material B-3-45 (CAS: 94665-63-1) were dissolved in toluene. Then, under a N2 atmosphere, 0.1 eq of Pd2(dba)3, 0.5 eq of P(t-Bu)3, and 2.0 eq of t-BuONa were added. The mixture was heated to 120 °C and stirred for 12 h. After the reaction was complete, the mixture was filtered hot using diatomaceous earth to remove salts and catalysts. The filtrate was cooled to room temperature, and distilled water was added to wash the filtrate. After separation, the organic phase was retained. The aqueous phase was extracted with ethyl acetate, and the combined organic layers were dried with magnesium sulfate. The solvent was removed using a rotary evaporator. Finally, the remaining substances were purified by column chromatography using a mixture of dichloromethane and petroleum ether (V:V = 1:14) as the eluent to obtain the compound shown in intermediate B-4-45 (yield: 67.2%).

[0088] S5. Mix the above products 1.0 eq intermediate B-4, 2. eq boron tribromide and 200 ml toluene, heat under reflux at 120 °C for 1 h, cool naturally, add to 25 ml 18% hydrochloric acid, cool to obtain a solid, add 5% NaOH to dissolve, filter out the insoluble matter, add 18% hydrochloric acid again, and the precipitated solid is the raw material B, with a yield of 60.8%.

[0089] HPLC purity: >99.7%.

[0090] Mass spectrometry test: Waters XEVO TQD mass spectrometer with ESI source.

[0091] MS (ESI, m / Z): [M+H]+: 411.45.

[0092] Step 2) Preparation of compound 45

[0093]

[0094] a) Under nitrogen atmosphere, 1.2 eq of starter A (CAS: 99266-81-6), 1.0 eq of starter B, 0.1 eq of cuprous iodide, 0.2 eq of 2-pyridinecarboxylic acid, and 2.0 eq of potassium phosphate were added to a flask, followed by 200 mL of DMSO. The reaction mixture was heated to 150 °C overnight. After cooling to room temperature, a large amount of water was added, and the mixture was extracted three times with dichloromethane. The organic phases were combined, evaporated to dryness, and purified by column chromatography to obtain intermediate 1 (yield: 67.9%).

[0095] b) Under nitrogen atmosphere, 1.0 eq of intermediate 1, 1.1 eq of starting material C (CAS: 534-85-0), 0.05 eq of Pd(OAc)2, 1.4 eq of S-Phos, 2.0 eq of NaOt-Bu, and 200 ml of xylene solution were added to a flask. The reaction was heated to 140 °C and stirred overnight. After cooling to room temperature, the mixture was evaporated to dryness and then purified by column chromatography to obtain intermediate 2 (yield: 67.5%).

[0096] c) Under nitrogen atmosphere, 1.0 eq of intermediate 3, 35 eq of triethyl formate, and 0.5 mL of concentrated hydrochloric acid were added to a flask. The reaction was heated to 100 °C and stirred overnight. The reaction was monitored by TLC until it was completed. After cooling to room temperature, the mixture was dried by rotary evaporation and then subjected to column chromatography to obtain intermediate 3 (yield: 66.1%).

[0097] d) Under nitrogen atmosphere, 1.0 eq intermediate 3, 0.6 eq Ag2O, and 20 mL DCE were added to a flask and reacted at room temperature for 12 h. After the reaction was complete, the solvent was evaporated under reduced pressure, and 1.1 eq (1,5-cyclooctadiene) platinum dichloride (Pt(COD)Cl2) was added. After adding 200 mL dichlorobenzene, the reaction was heated to 200 °C and stirred for 24 h. After the reaction was cooled to room temperature, compound 45 was obtained by column chromatography (yield: 59.7%).

[0098] HPLC purity: >99.7%.

[0099] Mass spectrometry test: Waters XEVO TQD mass spectrometer with ESI source.

[0100] MS (ESI, m / Z): [M+H]+: 872.47.

[0101] The synthesis methods for other compounds are the same as those in the above examples, and will not be described in detail here.

[0102] Device Example 1

[0103] The fabrication of a green organic electroluminescent device containing compound 9 specifically includes the following steps:

[0104] a. ITO anode: ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrates with coating thicknesses of 14nm / 150nm / 14nm are cleaned twice in distilled water, ultrasonically washed for 30 minutes, then repeatedly cleaned twice in distilled water, ultrasonically washed for 10 minutes, and baked in a vacuum oven at 220℃ for 2 hours. After baking, the substrates are cooled down before use. Using this substrate as the anode, the device is deposited using a vapor deposition machine, and other functional layers are deposited sequentially on it.

[0105] b. HIL (Hole Injection Layer): Hole injection layer materials HT-1 and P-1 are vacuum-deposited at a deposition rate of 1 Å / s, and their chemical formulas are shown below; the deposition rate ratio of HT-1 and P-1 is 95:5, and the thickness is 10 nm.

[0106] c. HTL (Hole Transport Layer): HT-1 with a thickness of 125 nm is vacuum-deposited on the hole injection layer at a deposition rate of 1.0 Å / s as the hole transport layer.

[0107] d. Prime (light-emitting auxiliary layer): HT-2 with a thickness of 45 nm was vacuum-deposited on the hole transport layer at a deposition rate of 0.5 Å / s as a light-emitting auxiliary layer;

[0108] e. EML (Light Emitting Layer): On the light-emitting auxiliary layer, a host material (GH-1+GH-2) and a dopant material (compound 9 of the present invention) with a total thickness of 40 nm are vacuum-deposited at a deposition rate of 1 Å / s. The GH-1 and GH-2 compounds are co-deposited with the dopant material as dual host materials. The mass ratio of GH-1 and GH-2 compounds is 50%:50%, and the deposition rate ratio of the host material to the dopant material is 88:12.

[0109] f. HBL (Hole Blocking Layer): A hole blocking layer ET-1 with a thickness of 5.0 nm is vacuum-deposited at a deposition rate of 0.5 Å / s.

[0110] g. ETL (Electron Transport Layer): ET-2 and Liq with a thickness of 30 nm are vacuum-deposited at a deposition rate of 1 Å / s as the electron transport layer; the deposition rate ratio of ET-2 to Liq is 1:1.

[0111] h. EIL (Electron Injection Layer): A 1.0 nm Yb film is deposited at a deposition rate of 0.5 Å / s to form an electron injection layer;

[0112] i. Cathode: Magnesium and silver are deposited at a deposition rate of 1 Å / s for 13 nm, with a deposition rate ratio of 1:9, to form the cathode;

[0113] j. Optical extraction layer: A CPL with a thickness of 60 nm is vacuum-deposited on the cathode at a deposition rate of 1 Å / s to serve as the optical extraction layer;

[0114] k. Encapsulate the vapor-deposited substrate; use a coating equipment to coat the cleaned cover plate with UV adhesive, move the coated cover plate to the pressing section, place the vapor-deposited substrate on the top of the cover plate, and bond the substrate and cover plate together under the action of the bonding equipment, while simultaneously completing the UV adhesive photocuring.

[0115] The required material structure is shown below:

[0116]

[0117] Device Examples 2-29

[0118] Referring to the above method, the doping material compound 9 used in device embodiment 1 was replaced with other compounds of the present invention as doping materials, as shown in Table 1.

[0119] Device Comparison Example 1-2:

[0120] The preparation method is the same as that of device example 1, except that: for device comparative examples 1-2, existing comparative compounds a and b are used to replace the doping materials in device example 1 for vapor deposition.

[0121] The chemical structural formulas of comparative compound a and comparative compound b are as follows:

[0122]

[0123] The driving voltage, luminous efficiency, and lifetime of the organic electroluminescent devices obtained in Examples 1 to 29 and Comparative Examples 1 to 2 were characterized at a brightness of 15000 nits. The test results are shown in Table 1 below (the test results are normalized to Comparative Example 1).

[0124] Table 1. Device Test Results

[0125]

[0126]

[0127] As shown in Table 1, the compounds of this application improve the intermolecular spatial configuration, exhibiting better spatial torsion capability and effectively modulating the HOMO and LUMO energy levels, thereby preventing carrier migration. They can be used as specific doping materials for the luminescent layer in organic electroluminescent devices. Devices 1-29 prepared using the luminescent layer doping materials provided by this invention show improved driving voltage, luminous efficiency, and lifetime compared to devices prepared using comparative compounds 1-2.

[0128] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0129] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A platinum-based phosphorescent doped material, characterized in that, The phosphorescent doped material has the compound structure shown in Formula I: In the formula, R is selected from substituted or unsubstituted C6-C. 30 aryl group; substituted or unsubstituted C6-C 30 The heteroaryl group, wherein the heteroatom is selected from oxygen, nitrogen, and sulfur; R1-R3 may be the same as or different from each other, and each is independently selected from hydrogen, deuterium, fluorine, cyano, C1-C 20 Alkyl and C1-C 20 Alkyl group; substituted or unsubstituted C6-C 30 aryl group; substituted or unsubstituted C6-C 30 The heteroaryl group, wherein the heteroatom is selected from oxygen, nitrogen, and sulfur; A and B are fused to the benzene ring, may be the same as or different from each other, and are each independently selected from hydrogen or any of the following groups. The dashed lines indicate the positions where they are fused to the adjacent benzene ring. At least one of A and B is one of the following groups: ； The substitution is monosubstituted, disubstituted, trisubstituted, or tetrasubstituted, and is selected from the following groups: deuterium, fluorine, cyano, and unsubstituted C6-C. 30 aryl group; unsubstituted C6-C 30 The heteroaryl group, wherein the heteroatom is selected from oxygen, nitrogen or sulfur.

2. The platinum-based phosphorescent doped material according to claim 1, characterized in that, R is selected from one or more of phenyl, biphenyl, terphenyl, naphthyl, carbazolyl, and fluorenyl; R1-R3 may be the same as or different from each other, and each is independently selected from one or more of hydrogen, deuterium, fluorine, cyano, methyl, ethyl, isopropyl, tert-butyl, phenyl, naphthyl, biphenyl, terphenyl, carbazole, and fluorenyl.

3. A platinum-based phosphorescent doped material, characterized in that, The platinum group compound phosphorescent doping material is selected from any one of the following compounds: 。 4. A method for synthesizing a platinum group compound phosphorescent doped material according to any one of claims 1 to 2, characterized in that, Includes the following steps: ； a) Under nitrogen atmosphere, raw material A, raw material B, cuprous iodide, 2-pyridinecarboxylic acid, and potassium phosphate were added to a flask, DMSO was added, the reaction was heated overnight after heating, and after cooling to room temperature, a large amount of water was added, the mixture was extracted, the organic phases were combined, dried by rotary evaporation, and purified by column chromatography to obtain the compound with the structure shown in intermediate 1. b) Under nitrogen atmosphere, intermediate 1, raw material C, Pd(OAc)2, S-Phos, NaOt-Bu, and xylene solution were added to a flask. The reaction was heated and stirred overnight. After cooling to room temperature, the mixture was dried by rotary evaporation and then subjected to column chromatography to obtain the compound with the structure shown in intermediate 2. c) Under nitrogen conditions, intermediate 2, triethyl formate, and concentrated hydrochloric acid were added to a flask. The reaction was heated to a certain temperature and stirred overnight. The reaction was monitored by TLC until it was completed. After cooling to room temperature, the mixture was dried by rotary evaporation and then subjected to column chromatography to obtain the compound with the structure shown in intermediate 3. d) Under nitrogen atmosphere, intermediate 3, Ag2O, and DCE (dichloroethane) were added to a flask. After the reaction was completed at room temperature, the solvent was evaporated under reduced pressure. Then, (1,5-cyclooctadiene)platinum dichloride (Pt(COD)Cl2) and dichlorobenzene were added. The reaction was heated to a certain temperature and stirred. After the reaction was cooled to room temperature, the compound with the structure shown in chemical formula I was obtained by column chromatography.

5. An organic electroluminescent device, characterized in that, The organic electroluminescent device comprises, in sequence, an anode, a hole injection layer, a hole transport layer, a light-emitting auxiliary layer, a light-emitting layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a cathode; the light-emitting layer contains a host material and a platinum-based phosphorescent doping material as described in any one of claims 1 to 3.

6. The organic electroluminescent device according to claim 5, characterized in that, The main material of the light-emitting layer is a dual-main material, and the evaporation rate ratio of the main material and the doped material is (99-1):(1-99).

7. The organic electroluminescent device according to claim 6, characterized in that, The main material of the light-emitting layer is a dual-material substrate, and the evaporation rate ratio of the main material to the doped material is 88:12.

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