Platinum compound phosphorescent doped material, preparation method, organic electroluminescent device and application

Abstract

The invention discloses a platinum compound phosphorescent doped material, a preparation method, an organic electroluminescent device and application, the phosphorescent doped material is a platinum compound with a structure as shown in a chemical formula I. According to the compound, a double-ring structure and a high-conjugate electron distribution system are introduced on the basis of a parent nucleus, so that electron distribution can be regulated and controlled and an excited state can be stabilized; the stability of the material is enhanced. The organic light-emitting device prepared by using the compound as a light-emitting layer doping material has the technical effects of high light-emitting efficiency, long service life and improvement of driving voltage.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic optoelectronic materials. Specifically, it particularly relates to a phosphorescent doping material of a platinum-based compound, a preparation method, an organic electroluminescent device and an application thereof. Background Art

[0002] An organic electroluminescent (OLED) device is a self-luminous device. Due to its characteristics such as low driving voltage, high brightness, fast response time, wide viewing angle, high resolution, simple process, flexibility and bendability, it has attracted much attention in the fields of new display technology and lighting technology. For example, the organic electroluminescent device (OLED) display technology has been applied in the fields of smart phones, tablet computers, etc., and will also expand to large-size application fields such as televisions.

[0003] An organic electroluminescent display (OLED) is an active light-emitting display device. Currently, small and medium-sized OLED display screens have been widely applied in high-end smart phones produced by companies such as Huawei, Xiaomi, and Samsung. Obtaining the best luminous efficiency of the device under low working voltage conditions is a common requirement in the OLED field.

[0004] OLED luminescence is divided into two ways: fluorescence luminescence and phosphorescence luminescence. In phosphorescence luminescence, singlet and triplet excitons are utilized. Compared with fluorescent materials that only utilize singlet excitons, the effective utilization of triplet excitons with a proportion as high as 75% enables the theoretical realization of 100% internal quantum efficiency for Ph OLEDs based on phosphorescent materials. In the past three years, phosphorescent materials have gradually replaced traditional fluorescent materials and become a research hotspot for OLED luminescent materials.

[0005] Currently, by combining a host material with a dopant to prepare a luminescent material to improve color purity, luminous efficiency, and stability, the dopant material can greatly affect the efficiency and performance of an organic light-emitting device. Therefore, it is crucial to develop a new host material and dopant material that meet the requirements of practicality. However, due to the relatively complex synthesis process, long time consumption, and low lifespan of phosphorescent materials, the further development of phosphorescent materials is extremely urgent. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a phosphorescent doping material of a platinum-based compound, a preparation method, an organic electroluminescent device and an application thereof. The green organic electroluminescent device prepared by using the phosphorescent doping material of the platinum-based compound has technical effects such as high luminous efficiency, long lifespan, and improved driving voltage.

[0007] To solve the above problems, the present invention provides the following technical solutions:

[0008] A phosphorescent doping material of a platinum-based compound has a compound structure shown in Chemical Formula I:

[0009]

[0010] Wherein, R is selected from substituted or unsubstituted C6-C 30 aryl; substituted or unsubstituted C6-C 30 heteroaryl, wherein the heteroatom is selected from oxygen, nitrogen, sulfur;

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

[0012] A and B are fused to the benzene ring where they are located, are the same as or different from each other, and are each independently selected from hydrogen or any one of the following groups, and the dotted part indicates the position fused to the benzene ring to which it is connected:

[0013]

[0014] In one embodiment of the present invention, R is selected from one or more of phenyl, biphenyl, terphenyl, naphthyl, furyl, carbazolyl, fluorene, pyridyl;

[0015] R1-R3 are the same as or different from each other, and are each independently selected from hydrogen, deuterium, fluorine, cyano, methyl, ethyl, isopropyl, tert-butyl, phenyl, naphthyl, biphenyl, terphenyl, furyl, carbazolyl, fluorene, pyridyl.

[0016] Wherein, the "substitution" is single substitution, double substitution, triple substitution or quadruple substitution, and is selected from the following groups: deuterium, fluorine, cyano, unsubstituted C6-C 30 aryl; unsubstituted C6-C30 heteroaryl, wherein the heteroatom is selected from oxygen, nitrogen, sulfur.

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

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

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

[0027] In a second aspect, the present invention also provides a method for synthesizing a phosphorescent doping material of a platinum-based compound having the structure shown in Chemical Formula I above, comprising the following steps:

[0028]

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

[0030] a) Under nitrogen conditions, raw material A, raw material B, cuprous iodide, 2-pyridinecarboxylic acid, and potassium phosphate are added to a flask, DMSO is added, and after the reaction temperature is raised, it is heated overnight. After cooling to room temperature, a large amount of water is added, extraction is carried out, the organic phases are combined, and after evaporation to dryness, the compound with the structure shown in Intermediate 1 is purified by column chromatography;

[0031] b) Under nitrogen conditions, Intermediate 1, raw material C, Pd(OAc)2, S-Phos, NaOt-Bu, and a xylene solution are added to a flask, and after the reaction temperature is raised, it is stirred overnight. After cooling to room temperature, the compound with the structure shown in Intermediate 2 is obtained by evaporation to dryness and then by column chromatography;

[0032] c) Under nitrogen conditions, Intermediate 2, triethyl formate, and concentrated hydrochloric acid are added to a flask, and after the reaction temperature is raised to a certain temperature, it is stirred overnight. After detecting the end of the reaction by TLC, it is cooled to room temperature, and the compound with the structure shown in Intermediate 3 is obtained by evaporation to dryness and then by column chromatography;

[0033] d) Under nitrogen conditions, Intermediate 3, Ag2O, and DCE (dichloroethane) are added to a flask. After the reaction is complete at room temperature, the solvent is evaporated under reduced pressure. After adding (1,5-cyclooctadiene) platinum dichloride (Pt(COD)Cl2) and dichlorobenzene, the reaction temperature is raised to a certain temperature and stirred. After the reaction is cooled to room temperature, the compound with the structure shown in Chemical Formula I is obtained by column chromatography.

[0034] In a third aspect, the present invention also provides a green organic electroluminescent device containing the above-mentioned phosphorescent doping material of a platinum-based compound having the structure shown in Chemical Formula I.

[0035] In one embodiment of the present invention, the green organic light-emitting 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, a light-emitting layer, and an electron transport region; the light-emitting layer contains a host material and a platinum-based compound phosphorescent doping material.

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

[0037] For example, the evaporation rate ratio of the host material to the doping 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-emitting 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 light-emitting 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, 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 may be glass or a polymer material with excellent mechanical strength, thermal stability, waterproofness, and transparency.

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

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

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

[0046] In one embodiment of the present invention, the anode material is selected from materials and their combinations that contribute to hole injection other than 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 serves as the cathode, metals or alloys such as magnesium (Mg), silver (Ag), aluminum (Al), aluminum-lithium (Al-Li), calcium (Ca), magnesium-indium (Mg-In), magnesium-silver (Mg-Ag), etc., and any combination thereof are preferably used.

[0048] In addition to the cathode materials listed above, the cathode material can also be materials and their combinations that contribute to 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, which are sequentially arranged; the light-emitting layer contains a host material and a phosphorescent doping material of a platinum-based compound.

[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, printing, etc.

[0051] In one embodiment of the present invention, the compound used as the organic material layer can be an organic small molecule, an organic macromolecule, 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 is a multi-layer 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 can be selected from phthalocyanine derivatives such as CuPc, conductive polymers, or polymers containing conductive dopants such as poly(phenylene vinylene), 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] In a fourth aspect, the present invention also provides an application of an organic electroluminescent device containing the above-mentioned platinum-based compound phosphorescent doping material 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, laptop computers, digital cameras, video cameras, viewfinders, microdisplays, three-dimensional displays, virtual reality or augmented reality displays, vehicles, video walls including a plurality of displays tiled together, theater or venue screens, light therapy devices, and signs.

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

[0057] The present invention provides a phosphorescent doping material, which is a platinum-based compound having the structure shown in Chemical Formula I. A bicyclic structure and a highly conjugated electron distribution system are introduced on the basis of the parent nucleus of the compound. Therefore, the electron distribution can be regulated and the excited state can be stabilized, enhancing the stability of the material. Using this compound as the doping material for the light-emitting layer, the prepared organic electroluminescent device has the technical effects of high luminous efficiency, long lifespan, and improved driving voltage. Description of the Drawings

[0058] Figure 1 It is the nuclear magnetic resonance hydrogen spectrum of Compound 9 in Example 1 of the present invention. Detailed Embodiments

[0059] The technical solutions 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 only for illustrative and explanatory purposes of the present invention, and should not be construed as limiting the protection scope 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 specified, the raw materials and reagents used in the following embodiments are all commercially available products.

[0061] Example 1

[0062] Step 1) Prepare raw material B:

[0063]

[0064] S1. Under nitrogen protection, 1.0 eq of B-1 (CAS: 2980689-07-2) and 1.1 eq of bis(pinacolato)diboron were dissolved in a 1,4-dioxane solution. Potassium acetate (2.0 eq) and PdCl2(dppf) (0.05 eq) were added, and the mixture was stirred evenly. Then the temperature was raised to 110 °C and refluxed for 10 h. After the reaction, the temperature was slightly lowered, and filtration was carried out using diatomaceous earth to remove salts and the catalyst. After the filtrate was cooled to room temperature, it was washed three times with water, and the organic phase was retained. Then the aqueous phase was extracted with ethyl acetate. After combining the organic phases, drying was carried out using anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator. The remaining material 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). Then the gas was replaced three times, and potassium carbonate (2.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added under nitrogen protection. The mixture was stirred evenly, the temperature was raised to 85 °C and refluxed for 8 h. After the reaction, the temperature was slightly lowered, and filtration was carried out using diatomaceous earth to remove salts and the catalyst. After the filtrate was cooled to room temperature, it was washed three times with water, and the organic phase was retained. Then the aqueous phase was extracted with ethyl acetate. After combining the organic phases, drying was carried out using anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator to obtain a solid powder, namely the compound shown in intermediate B-2 (yield 75.1%).

[0066] S3. 1.0 eq of intermediate B-2, 0.1 eq of bis(trifluoromethanesulfonyl)imide and 2.0 eq of hexafluoroisopropanol were added to a dry 100 ml round-bottom flask, and a magnetic stirrer was added and stirred until completely dissolved. Then 1.3 eq of iodobenzene bis(trifluoroacetate) was slowly added over about 5 min. Subsequently, the mixture was stirred at room temperature for 0.5 h. After the reaction was complete, column chromatography separation was carried out to obtain the compound shown in intermediate B-3 (yield 61.5%).

[0067] S4. Dissolve 1.0 eq of intermediate B-3 and 1.0 eq of raw material B-3 (CAS: 94665-63-1) in toluene. Then, under a nitrogen atmosphere, add 0.1 eq of Pd2(dba)3, 0.5 eq of P(t-Bu)3, and 2.0 eq of t-BuONa. Heat the mixture to 120 °C and stir for 12 h. After the reaction is completed, filter while hot using diatomaceous earth to remove salts and catalysts. After the filtrate is cooled to room temperature, add distilled water to the filtrate for washing. After liquid separation, retain the organic phase. Extract the aqueous phase with ethyl acetate. Then, dry the combined organic layers using magnesium sulfate and remove the solvent using a rotary evaporator. Finally, purify the remaining material 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 1.0 eq of the above product intermediate B-4, 2.0 eq of boron tribromide, and 200 ml of toluene. Heat under reflux at 120 °C for 1 h, cool naturally, add to 25 ml of 18% hydrochloric acid by mass concentration. After cooling, a solid is obtained. Add a 5% NaOH solution by mass concentration to dissolve it, filter out the insoluble matter, and then add an 18% hydrochloric acid solution by mass concentration. A solid precipitates, which is the compound shown in raw material B, with a yield of 64.3%.

[0069] HPLC purity: >99.7%.

[0070] Mass spectrometry test: A mass spectrometer of model Waters XEVO TQD, using an ESI source.

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

[0072] Step 2) Prepare compound 9

[0073]

[0074] a) Under nitrogen conditions, add 1.0 eq of raw material B, 1.2 eq of raw material 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 to a flask. Add 200 ml of DMSO. After the reaction temperature is raised to 150 °C, heat overnight. After cooling to room temperature, add a large amount of water. Extract three times using dichloromethane, combine the organic phases, and after rotary evaporation, purify 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 raw 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 temperature was raised to 140 °C and stirred overnight. After cooling to room temperature, the solvent was evaporated under reduced pressure and the compound with the structure shown in intermediate 2 was obtained by column chromatography (yield: 68.3%).

[0076] c) Under nitrogen atmosphere, 1.0 eq of intermediate 2, 35 eq of triethyl formate and 0.5 mL of concentrated hydrochloric acid were added to a flask. The reaction temperature was raised to 100 °C and stirred overnight. After the reaction was completed as detected by TLC, it was cooled to room temperature. The solvent was evaporated under reduced pressure and the compound with the structure shown in intermediate 3 was obtained by column chromatography (yield: 69.2%).

[0077] d) Under nitrogen atmosphere, 1.0 eq of intermediate 3, 0.6 eq of Ag2O and 20 mL of 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. 1.1 eq of dichlorobis(1,5-cyclooctadiene)platinum (Pt(COD)Cl2) was added. After adding 200 mL of dichlorobenzene, the reaction temperature was raised 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: A mass spectrometer of model Waters XEVO TQD was used, with an 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 bis(pinacolato)diboron were dissolved in 1,4-dioxane solution. Potassium acetate (2.0 eq) and PdCl2(dppf) (0.05 eq) were added, and the mixture was stirred evenly. Then the temperature was raised to 110 °C and refluxed for 10 h. After the reaction, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and catalysts. After the filtrate was cooled to room temperature, it was washed three times with water, and the organic phase was retained. Then the aqueous phase was extracted with ethyl acetate. After combining the organic phases, they were dried with anhydrous magnesium sulfate, and 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). Then the gas was exchanged three times, and potassium carbonate (2.0 eq) and tetrakis(triphenylphosphine)palladium (0.01 eq) were added under nitrogen protection. The mixture was stirred evenly, the temperature was raised to 85 °C and refluxed for 8 h. After the reaction, the temperature was slightly lowered, and the mixture was filtered through diatomaceous earth to remove salts and catalysts. After the filtrate was cooled to room temperature, it was washed three times with water, and the organic phase was retained. Then the aqueous phase was extracted with ethyl acetate. After combining the organic phases, they were dried with anhydrous magnesium sulfate, and the solvent was removed using a rotary evaporator to obtain a solid powder, i.e., intermediate B-2-45 (yield 70%);

[0086] S3. 1.0 eq of intermediate B-2-45, 0.1 eq of bis(trifluoromethanesulfonyl)imide and 2.0 eq of hexafluoroisopropanol were added to a dry 100 ml round-bottom flask. A magnetic stirrer was added and stirred until completely dissolved. Then 1.3 eq of iodobenzene bis(trifluoroacetate) was slowly added over about 5 min. Subsequently, the mixture was stirred at room temperature for 0.5 h. After the reaction was complete, it was separated by column chromatography to obtain intermediate B-3-45 (yield 69.3%);

[0087] S4. Dissolve 1.0 eq of intermediate B-3-45 and 1.0 eq of raw material B-3-45 (CAS: 94665-63-1) in toluene, then add 0.1 eq of Pd2(dba)3, 0.5 eq of P(t-Bu)3 and 2.0 eq of t-BuONa under a N2 atmosphere. Heat the mixture to 120 °C and stir for 12 h. After the reaction is completed, filter while hot using diatomaceous earth to remove salts and catalysts. After the filtrate is cooled to room temperature, add distilled water to the filtrate for washing. After liquid separation, retain the organic phase, extract the aqueous phase with ethyl acetate, then dry the combined organic layers using magnesium sulfate, and remove the solvent using a rotary evaporator. Finally, use a mixture of dichloromethane and petroleum ether (V:V = 1:14) as the eluent to purify the remaining material by column chromatography to obtain the compound shown in intermediate B-4-45 (yield: 67.2%);

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

[0089] HPLC purity: >99.7%.

[0090] Mass spectrometry test: A mass spectrometer of model Waters XEVO TQD, using an ESI source.

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

[0092] Step 2) Prepare compound 45

[0093]

[0094] a) Under nitrogen conditions, add 1.2 eq of raw material A (CAS: 99266-81-6), 1.0 eq of raw material B, 0.1 eq of cuprous iodide, 0.2 eq of 2-pyridinecarboxylic acid, and 2.0 eq of potassium phosphate to a flask, add 200 ml of DMSO, heat the reaction to 150 °C and heat overnight. After cooling to room temperature, add a large amount of water, extract three times with dichloromethane, combine the organic phases, spin dry and purify 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 raw 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 solvent was evaporated under reduced pressure, and intermediate 2 was obtained by column chromatography (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. After monitoring the reaction by TLC until completion, the reaction mixture was cooled to room temperature, the solvent was evaporated under reduced pressure, and intermediate 3 was obtained by column chromatography (yield: 66.1%).

[0097] d) Under nitrogen atmosphere, 1.0 eq of intermediate 3, 0.6 eq of Ag2O, and 20 ml of DCE were added to a flask. The reaction was carried out at room temperature for 12 h. After the reaction was complete, the solvent was evaporated under reduced pressure. Then, 1.1 eq of dichlorobis(1,5-cyclooctadiene)platinum(II) (Pt(COD)Cl2) was added, and 200 mL of dichlorobenzene was added. 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: A mass spectrometer of model Waters XEVO TQD was used, with an ESI source.

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

[0101] The synthesis methods of other compounds are the same as those in the above examples and will not be elaborated here one by one.

[0102] Device Example 1

[0103] To fabricate a green organic light-emitting device containing compound 9, the following steps are specifically included:

[0104] a. ITO anode: An ITO (indium tin oxide)-Ag-ITO (indium tin oxide) glass substrate with a coating thickness of 14 nm / 150 nm / 14 nm was washed twice in distilled water, ultrasonically washed for 30 min, then repeatedly washed twice with distilled water, ultrasonically washed for 10 min, and baked in a vacuum oven at 220 °C for 2 hours. After baking, it was cooled to room temperature for use. Using this substrate as the anode, a vapor deposition machine was used for the vapor deposition process of the device, and other functional layers were sequentially vapor deposited thereon;

[0105] b. HIL (Hole Injection Layer): Vacuum deposit the hole injection layer materials HT-1 and P-1 at a deposition rate of 1 Å / s, and their chemical formulas are as follows; 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): Vacuum deposit HT-1 with a thickness of 125 nm as the hole transport layer on the hole injection layer at a deposition rate of 1.0 Å / s;

[0107] d. Prime (Luminescence-Assisting Layer): Vacuum deposit HT-2 with a thickness of 45 nm as the luminescence-assisting layer on the hole transport layer at a deposition rate of 0.5 Å / s;

[0108] e. EML (Emission Layer): On the luminescence-assisting layer, vacuum deposit a total thickness of 40 nm of the (GH-1 + GH-2) host material and the doping material (Compound 9 of the present invention) at a deposition rate of 1 Å / s. Among them, the GH-1 and GH-2 compounds are co-evaporated with the doping material as a double host material, and the mass ratio of the GH-1 and GH-2 compounds is 50%:50%. The deposition rate ratio of the host material and the doping material is 88:12;

[0109] f. HBL (Hole Blocking Layer): Vacuum deposit the hole blocking layer ET-1 with a thickness of 5.0 nm at a deposition rate of 0.5 Å / s;

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

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

[0112] i. Cathode: Deposit magnesium and silver with a thickness of 13 nm at a deposition rate ratio of 1 Å / s, and the deposition rate ratio is 1:9 to form the cathode;

[0113] j. Light Extraction Layer: Vacuum deposit CPL with a thickness of 60 nm on the cathode at a deposition rate of 1 Å / s as the light extraction layer;

[0114] k. Package the deposited substrate; use a coating device to coat the cleaned cover plate with UV glue, move the coated cover plate to the lamination section, place the deposited substrate on the upper end of the cover plate, and laminate the substrate and the cover plate under the action of a laminating device, while completing the photo-curing of the UV glue.

[0115] The structures of the required materials are as follows:

[0116]

[0117] Device Example 2 - Device Example 29

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

[0119] Device Comparative Examples 1 - 2:

[0120] The preparation method is the same as that of Device Example 1, except that: in Device Comparative Examples 1 - 2, the existing comparative compound a and comparative compound b were respectively used to replace the doping material in the above Device Example 1 for evaporation coating.

[0121] Among them, 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 above-mentioned organic electroluminescent devices obtained in Device Examples 1 - 29 and Device Comparative Examples 1 - 2 were characterized at a brightness of 15000 (nits), and the test results are shown in Table 1 below (the test results are normalized with respect to Comparative Example 1).

[0124] Table 1. Device Test Results

[0125]

[0126]

[0127] As can be seen from Table 1, the compound of the present application has a better spatial torsion ability by improving the intermolecular spatial configuration, effectively regulates the HOMO and LUMO energy levels, thereby avoiding carrier migration, and can be used as a specific doping material for the light-emitting layer and applied to organic electroluminescent devices. Compared with Device Comparative Examples 1 - 2 prepared with Comparative Compounds 1 - 2, the driving voltage, luminous efficiency and lifetime of Device Examples 1 - 29 obtained using the light-emitting layer doping material provided by the present invention are all improved.

[0128] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0129] The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present 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 present invention. Thus, the present invention is not intended 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 compound phosphorescent doping material, characterized in that, The phosphorescent doping material has a compound structure shown in Chemical Formula I: In the formula, R is selected from substituted or unsubstituted C6-C 30 aryl; substituted or unsubstituted C6-C 30 heteroaryl, wherein the heteroatom is selected from oxygen, nitrogen, sulfur; R1 - R3 are the same as or different from each other and are each independently selected from hydrogen, deuterium, fluorine, cyano, C1 - C 20 alkyl and C1 - C 20 alkoxy; substituted or unsubstituted C6 - C 30 aryl; substituted or unsubstituted C6 - C 30 heteroaryl, wherein the heteroatom is selected from oxygen, nitrogen, sulfur; A and B are fused to the benzene ring where they are located, the same or different from each other, and each independently selected from hydrogen or any one of the following groups. The dotted part indicates the position fused to the benzene ring to which it is connected:

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

3. The platinum-based compound phosphorescent doping material according to claim 1, characterized in that, The "substitution" is mono-substitution, di-substitution, tri-substitution or tetra-substitution, and is selected from the following groups: deuterium, fluorine, cyano group, unsubstituted C6-C 30 aryl; unsubstituted C6-C 30 heteroaryl, wherein the heteroatom is selected from oxygen, nitrogen or sulfur.

4. The platinum group compound phosphorescent doping material according to claim 1, characterized in that, The platinum-based compound phosphorescent doping material is selected from any one of the following compounds:

5. A method for synthesizing a platinum-based compound phosphorescent doping material according to any one of claims 1 to 4, characterized in that, Comprising the following steps: The specific preparation process includes: a) Under nitrogen conditions, raw material A, raw material B, cuprous iodide, 2-pyridinecarboxylic acid, and potassium phosphate are added to a flask, DMSO is added, and after the reaction temperature is raised, it is heated overnight. After cooling to room temperature, a large amount of water is added, extracted, the organic phases are combined, and after evaporation to dryness, the compound with the structure shown in Intermediate 1 is purified by column chromatography; b) Under nitrogen conditions, Intermediate 1, raw material C, Pd(OAc)2, S-Phos, NaOt-Bu, and xylene solution are added to a flask, and after the reaction temperature is raised, it is stirred overnight. After cooling to room temperature, the compound with the structure shown in Intermediate 2 is obtained by column chromatography after evaporation to dryness; c) Under nitrogen conditions, Intermediate 2, triethyl formate, and concentrated hydrochloric acid are added to a flask, and after the reaction temperature is raised to a certain temperature, it is stirred overnight. After detecting the end of the reaction by TLC, it is cooled to room temperature, and the compound with the structure shown in Intermediate 3 is obtained by column chromatography after evaporation to dryness; d) Under nitrogen conditions, Intermediate 3, Ag2O, and DCE (dichloroethane) are added to a flask. After the reaction is complete at room temperature, the solvent is evaporated under reduced pressure. After adding (1,5-cyclooctadiene) platinum dichloride (Pt(COD)Cl2) and dichlorobenzene, the reaction temperature is raised to a certain temperature and stirred. After the reaction is cooled to room temperature, the compound with the structure shown in Chemical Formula I is obtained by column chromatography.

6. An organic electroluminescent device, characterized in that, The 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 in sequence; the light-emitting layer contains a host material and the platinum-based compound phosphorescent doping material according to any one of Claims 1 to 4.

7. The organic electroluminescent device according to claim 6, wherein, The host material of the light-emitting layer is a double host material, and the evaporation rate ratio of the host material to the doping material is (99 - 1):(1 - 99).

8. The organic electroluminescent device according to claim 7, wherein The host material of the light-emitting layer is a double host material, and the evaporation rate ratio of the host material to the doping material is 88:

12.

9. Use of the platinum-based compound phosphorescent doping material according to any one of claims 1 to 4 or the organic electroluminescent device according to any one of claims 6 to 8 in a smart phone, a flat panel display, a computer monitor, a medical monitor, a television set, a billboard, a lamp for internal or external illumination and / or signaling, a head-up display, a fully transparent or partially transparent display, a flexible display, a laser printer, a telephone, a tablet, an album, a personal digital assistant, a wearable device, a laptop computer, a digital camera, a video camera, a viewfinder, a microdisplay, a three-dimensional display, a virtual reality or augmented reality display, a vehicle, a video wall including a plurality of displays tiled together, a theater or venue screen, a light therapy device, and a sign.

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