Electroluminescent device, multi-nuclear copper cluster complex guest material, preparation method and application thereof

Abstract

The present invention provides a multi-nuclear copper cluster complex guest material synthesized based on a fluorine-containing tridentate phosphine ligand unit, belonging to the technical field of luminescent materials. The present invention uses a fluorine-containing tridentate phosphine as a matrix, introduces different numbers of fluorine atoms into the matrix, and forms a multi-nuclear copper cluster complex by coordinating with copper. The present invention prepares a variety of fluorine-containing tridentate phosphine multi-nuclear copper cluster complex materials by changing the number of fluorine atoms and different coordination conditions. Among them, the rigid multi-nuclear copper cluster complex synthesized using the fluorine-containing tridentate phosphine ligand has excellent photoluminescent properties, and can therefore be used as a luminescent layer guest material to prepare a vapor-deposited electroluminescent device with high external quantum efficiency, high brightness, and low turn-on voltage.

Description

Technical Field

[0001] The present invention relates to the technical field of luminescent materials, and in particular to a multinuclear copper cluster complex guest material synthesized based on a fluorine-containing tridentate phosphine ligand unit, a method for preparing the guest material, an application of the guest material in an electroluminescent device, and an electroluminescent device comprising the multinuclear copper cluster complex guest material. Background Art

[0002] Organic Light Emitting Diodes (OLEDs) are a type of background-free light source used in lighting and display applications. Over the past few decades, OLED research and development has continued uninterrupted, offering a new, efficient and long-lasting approach to both lighting and display. OLEDs are gradually replacing existing technologies and expanding their practical applications. In the display industry, OLEDs have become a focal point in recent years, particularly due to their significantly superior performance compared to established technologies like liquid crystal displays (LCDs).

[0003] In 1963, Pope et al. used organic materials to convert electrical energy into light energy for the first time, which is considered to be the earliest discovery of electroluminescence. They used silver electrodes as a basis and applied direct current to anthracene single crystals to make anthracene emit fluorescence. However, this process requires a very high driving voltage (400V), so it cannot be applied in practice. In 1987, Tang and Van Slyke reported the preparation of a double-layer device by using tris(8-hydroxyquinoline)aluminum as the light-emitting layer and the electron transport layer, which was a major breakthrough in the development of OLEDs. When the driving voltage is lower than 10V, the external quantum efficiency (EQE) of the green light-emitting device is about 1%. This work broke the barriers to the development of OLEDs and ushered in a new era. Academia and industry have shown great interest in this pioneering work and have carried out research. According to spin statistics, in OLED devices, the recombination of charges (holes and electrons) to form excitons produces approximately 25% singlet excitons (S1) and 75% triplet excitons (T1). However, fluorescent devices can only utilize a maximum of 25% of the S1 excitons for light emission. To overcome this low device efficiency, Baldo et al. reported an OLED device in 1998. They used a fluorescent material as the host and a red-emitting organometallic complex as the luminescent material, achieving efficient energy transfer from the host to the guest. Furthermore, due to spin-orbit coupling, they achieved an internal quantum efficiency (IQE) of 100%, with reported EQE and IQE of 4% and 23%, respectively. This was a pioneering study in phosphorescent OLEDs. The value of using organometallic complexes as emitters lies in their ability to achieve a 100% IQE by allowing the S1 to enter the T1 through intersystem crossing (ISC) through strong spin-orbit coupling mediated by heavy metals (such as Ir and Pt) in the complex. However, heavy metal materials are not only expensive, leading to increased costs, but the potential environmental pollution is also a worrying factor. In addition, although the red and green light devices of organometallic materials show excellent performance parameters, the corresponding blue light-emitting materials still need to be improved in terms of their device stability, color purity and brightness. In 2012, Adachi and his colleagues first proposed Thermally Activated Delayed Fluorescence (TADF), which brought the research of OLEDs into a new era. TADF materials use pure organic small molecules. When the energy level difference between S1 and T1 (Singlet-Triplet SplittingEnergies, ΔE ST) is sufficiently small, the T1 state can transition to the S1 state via reverse intersystem crossing (RISC), thereby utilizing the S1 state for emission, also achieving a 100% IQE. In recent years, OLED display technology has been widely used in small and medium-sized displays, but further development is needed in large-scale displays and lighting.

[0004] The OLED device structure typically consists of a glass substrate, anode and cathode electrodes, two injection layers, two transport layers, and, crucially, a light-emitting layer. Under applied voltage, holes generated at the anode and electrons generated at the cathode pass through the hole injection layer, hole transport layer, and electron injection layer, electron transport layer, respectively, before recombining in the light-emitting layer to form excitons. These excitons then radiatively transition back to the ground state, generating light. Currently, OLED fabrication processes commonly used are evaporation and spin coating. Vacuum evaporation deposits materials under high temperature and high vacuum to form dense thin films. While suitable for materials with good thermal stability, it suffers from low material utilization, high material consumption, and complex, costly processes, making it unsuitable for large-area panel fabrication. Spin coating, on the other hand, is simpler to prepare and suitable for materials with good solubility, offering high material utilization and suitability for large-area panel fabrication. However, it suffers from lower device efficiency and stability. Currently, OLEDs still face several challenges, including short device lifespan, poor stability, and currently high production costs. However, we believe that these challenges will be addressed in the near future, enabling greater industrialization.

[0005] Of particular interest is the remarkable luminescence behavior of copper cluster complexes, resulting from their rich coordination modes and inherent copper-philic interactions. These complexes have emerged as emerging emitters for OLEDs, offering promising applications in sustainable displays and lighting. In 2016, our group reported a tridentate phosphine copper iodide complex, designated TTPPCuX, which exhibits excellent thermal stability and rigidity. The incorporated tridentate phosphine ligand exhibits excellent rigidity. When these copper cluster complexes were used to fabricate vapor-deposited devices, the devices exhibited yellow-green emission upon illumination. This work successfully demonstrated the enormous potential and superiority of copper cluster complexes as optoelectronic integrated systems in a variety of device applications, as well as the significance of ligand engineering. Summary of the Invention

[0006] In view of this, to address the technical issues of expensive heavy metals and environmental pollution, as well as the low efficiency of polynuclear copper cluster complexes due to structural distortion and the annihilation of excited states, the present invention provides, in a first aspect, polynuclear copper cluster complex guest materials synthesized based on fluorine-containing tridentate phosphine ligand units. By varying the number of fluorine atoms and different coordination conditions, a variety of fluorine-containing tridentate phosphine polynuclear copper cluster complex materials are prepared. Among them, the rigid polynuclear copper cluster complex synthesized using fluorine-containing tridentate phosphine ligands exhibits excellent photoluminescent properties and can therefore be used as a guest material for the light-emitting layer to prepare vapor-deposited electroluminescent devices with high external quantum efficiency, high brightness, and low turn-on voltage.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] The multi-nuclear copper cluster complex guest material is synthesized based on the fluorine-containing tridentate phosphine ligand unit. The fluorine-containing tridentate phosphine is used as the matrix, and different numbers of fluorine atoms are introduced into the matrix to form a multi-nuclear copper cluster complex by coordinating with copper.

[0009] Preferably, the multi-nuclear copper cluster complex guest material is a compound having the following structural formula:

[0010]

[0011] Wherein, R is the receptor F.

[0012] Preferably, the multi-nuclear copper cluster complex guest material is one of the following compounds I to V:

[0013]

[0014] In a second aspect, the present invention provides a method for preparing the above-mentioned multi-nuclear copper cluster complex guest material, using o-dibromobenzene or p-fluoro-o-dibromobenzene as a raw material and diphenylphosphine to synthesize a monophosphine monobromo ligand, which is then reacted with phenylphosphine dichloride to form a fluorine-containing tridentate phosphine ligand, and finally coordinated with cuprous iodide to prepare the material.

[0015] Preferably, the method specifically includes the following steps:

[0016] Step (1), adding diphenylphosphine to o-dibromobenzene or p-fluoro-o-dibromobenzene compound to obtain a monophosphine monobromo ligand;

[0017] Step (2), adding phenylphosphine dichloride to the monophosphine monobromine ligand prepared in step (1) to obtain a fluorine-containing tridentate phosphine ligand;

[0018] Step (3), adding the fluorine-containing tridentate phosphine ligand obtained in step (2) and cuprous iodide to a solvent, reacting at room temperature to obtain a reaction solution;

[0019] Step (4): post-treating the reaction solution to obtain a multi-nuclear copper cluster complex guest material.

[0020] Preferably, the reaction temperatures of step (1) and step (2) are -120°C and -78°C, respectively.

[0021] Preferably, the molar ratio of the fluorine-containing tridentate phosphine ligand to the cuprous iodide is 1:(1-12).

[0022] In a third aspect, the present invention provides the use of the multi-nuclear copper cluster complex guest material synthesized based on the fluorine-containing tridentate phosphine ligand unit in an electroluminescent device.

[0023] Preferably, the multi-nuclear copper cluster complex guest material synthesized based on the fluorine-containing tridentate phosphine ligand unit is used as the light-emitting layer in the electroluminescent device.

[0024] In a fourth aspect, the present invention provides an electroluminescent device comprising a light-emitting layer, wherein the light-emitting layer comprises the multi-nuclear copper cluster complex guest material synthesized based on the fluorine-containing tridentate phosphine ligand unit.

[0025] By varying the number of fluorine atoms and different coordination conditions, a variety of fluorinated tridentate phosphine multinuclear copper cluster complex materials were prepared. Among them, the rigid multinuclear copper cluster complex synthesized using a fluorinated tridentate phosphine ligand exhibits excellent photoluminescence properties and can therefore be used as a guest material in the light-emitting layer to prepare vapor-deposited electroluminescent devices with high external quantum efficiency, high brightness, and low turn-on voltage. Compared to existing technologies, this method offers the following advantages:

[0026] (1) The multi-nuclear copper cluster complex guest material synthesized based on the fluorine-containing tridentate phosphine ligand unit provided in the present invention has good electron transport properties. Different numbers of fluorine atoms can be modified to adjust different luminescence colors, and different electron-withdrawing abilities can adjust the distance between Cu-Cu. At the same time, the tridentate phosphine ligand is used to provide coordination sites to form a copper complex with a rigid structure, which can be used to prepare high-efficiency vapor-deposited electroluminescent devices.

[0027] (2) The electroluminescence peak of the multinuclear copper cluster complex guest material synthesized based on the fluorine-containing tridentate phosphine ligand unit of the present invention is 450-550nm, which is a type of blue-luminescent organic copper cluster complex guest material. The electroluminescence peak of the trinuclear copper cluster complex guest material is 550-650nm, which is a type of organic copper cluster complex guest material with adjustable luminescence color, providing a new idea for electroluminescent devices based on organic multinuclear copper cluster complex guest materials.

[0028] (3) The fluorine-containing tridentate phosphine multinuclear copper cluster complex guest material in the present invention has good photoluminescence properties. In particular, the external quantum efficiency of the prepared electroluminescent device is the best among the multinuclear fluorine-containing tridentate phosphine copper cluster complex guest materials, and the current efficiency and power efficiency are effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The UV spectrum and fluorescence spectrum test spectra of Example 1 and Example 2 of the present invention are shown;

[0030] Figure 2 The UV spectrum and fluorescence spectrum test spectra of Example 3, Example 4 and Example 5 of the present invention are shown;

[0031] Figure 3 The voltage-brightness relationship curve, voltage-current density relationship curve and electroluminescence spectrum of the electroluminescent device of compound (I) in Example 1 of the present invention are shown;

[0032] Figure 4 The brightness-current efficiency relationship curve, brightness-power efficiency relationship curve and brightness-external quantum efficiency relationship curve of the electroluminescent device of compound (I) in Example 1 of the present invention are shown;

[0033] Figure 5 The voltage-brightness relationship curve, voltage-current density relationship curve and electroluminescence spectrum of the electroluminescent device of compound (II) in Example 2 of the present invention are shown;

[0034] Figure 6 The brightness-current efficiency relationship curve, brightness-power efficiency relationship curve and brightness-external quantum efficiency relationship curve of the electroluminescent device of compound (II) in Example 2 of the present invention are shown;

[0035] Figure 7 The voltage-brightness relationship curve, voltage-current density relationship curve and electroluminescence spectrum of the electroluminescent device of compound (III) in Example 3 of the present invention are shown;

[0036] Figure 8 These are the brightness-current efficiency relationship curve, the brightness-power efficiency relationship curve, and the brightness-external quantum efficiency relationship curve of the electroluminescent device of compound (III) in Example 3 of the present invention.

[0037] Figure 9 The voltage-brightness relationship curve, voltage-current density relationship curve and electroluminescence spectrum of the electroluminescent device of compound (IV) in Example 4 of the present invention are shown;

[0038] Figure 10 The brightness-current efficiency relationship curve, brightness-power efficiency relationship curve and brightness-external quantum efficiency relationship curve of the electroluminescent device of compound (IV) in Example 4 of the present invention are shown;

[0039] Figure 11 The voltage-brightness relationship curve, voltage-current density relationship curve and electroluminescence spectrum of the electroluminescent device of compound (V) in Example 5 of the present invention are shown;

[0040] Figure 12 These are the brightness-current efficiency relationship curve, the brightness-power efficiency relationship curve, and the brightness-external quantum efficiency relationship curve of the electroluminescent device of compound (V) in Example 5 of the present invention.

[0041] Figure 13 The voltage-brightness relationship curve, voltage-current density relationship curve and electroluminescence spectrum of the electroluminescent device of compound (I) in Example 1 of the present invention are shown;

[0042] Figure 14 The brightness-current efficiency relationship curve, brightness-power efficiency relationship curve and brightness-external quantum efficiency relationship curve of the electroluminescent device of compound (I) in Example 1 of the present invention are shown;

[0043] Figure 15 The voltage-brightness relationship curve, voltage-current density relationship curve and electroluminescence spectrum of the electroluminescent device of compound (II) in Example 2 of the present invention are shown;

[0044] Figure 16 The brightness-current efficiency relationship curve, brightness-power efficiency relationship curve and brightness-external quantum efficiency relationship curve of the electroluminescent device of compound (II) in Example 2 of the present invention are shown;

[0045] Figure 17 The voltage-brightness relationship curve, voltage-current density relationship curve and electroluminescence spectrum of the electroluminescent device of compound (III) in Example 3 of the present invention are shown;

[0046] Figure 18 These are the brightness-current efficiency relationship curve, the brightness-power efficiency relationship curve, and the brightness-external quantum efficiency relationship curve of the electroluminescent device of compound (III) in Example 3 of the present invention.

[0047] Figure 19 The voltage-brightness relationship curve, voltage-current density relationship curve and electroluminescence spectrum of the electroluminescent device of compound (IV) in Example 4 of the present invention are shown;

[0048] Figure 20 The brightness-current efficiency relationship curve, brightness-power efficiency relationship curve and brightness-external quantum efficiency relationship curve of the electroluminescent device of compound (IV) in Example 4 of the present invention are shown;

[0049] Figure 21 The voltage-brightness relationship curve, voltage-current density relationship curve and electroluminescence spectrum of the electroluminescent device of compound (V) in Example 5 of the present invention are shown;

[0050] Figure 22These are the brightness-current efficiency relationship curve, the brightness-power efficiency relationship curve, and the brightness-external quantum efficiency relationship curve of the electroluminescent device of compound (V) in Example 5 of the present invention.

[0051] Figure 23 : is the single crystal structure diagram of compound (I) in Example 1 of the present invention;

[0052] Figure 24 : is the single crystal structure diagram of compound (II) in Example 2 of the present invention;

[0053] Figure 25 : is the single crystal structure diagram of compound (IV) in Example 4 of the present invention;

[0054] Figure 26 : is the single crystal structure diagram of compound (V) in Example 5 of the present invention;

[0055] Figure 27 This is the H NMR spectrum of compound (III) in Example 3 of the present invention. DETAILED DESCRIPTION

[0056] The multinuclear copper cluster complex guest material provided in the present invention, which is synthesized based on a fluorine-containing tridentate phosphine ligand unit, is a compound having the following general structural formula:

[0057]

[0058] Wherein R is the acceptor F (fluorine atom).

[0059] Preferably, the multi-nuclear copper complex guest material is selected from compounds I to V:

[0060] When R is four fluorine atoms, the compound is (I) (4FTTPPCu6I6) or (IV) (4FTTPP-TPP-Cu3I3);

[0061] When R is five fluorine atoms, the compound is (II) (5FTTPPCu6I6) or (V) (5FTTPP-TPP-Cu3I3);

[0062] When R is a fluorine atom, the compound is (III) (FTTPP-TPP-Cu3I3);

[0063] The structural formulas of the compounds are as follows:

[0064]

[0065] The present invention provides a preparation method for the above-mentioned multi-nuclear copper cluster complex guest material based on the synthesis of fluorine-containing tridentate phosphine ligand units. The method uses a fluorine-containing tridentate phosphine as a matrix, uses o-dibromobenzene or p-fluoro-o-dibromobenzene as a raw material, and synthesizes a monophosphine monobromo ligand with diphenylphosphine, which is then reacted with phenylphosphine dichloride to form a fluorine-containing tridentate phosphine ligand, and finally coordinated with cuprous iodide to prepare the multi-nuclear copper cluster complex guest material.

[0066] The method for preparing the multi-nuclear copper cluster complex guest material based on the synthesis of the fluorine-containing tridentate phosphine ligand unit provided by the present invention may specifically include the following steps:

[0067] Step (1), at a temperature of -120 ° C, diphenylphosphine is added to o-dibromobenzene or p-fluoro-o-dibromobenzene compound to obtain a reaction solution of monophosphine monobromo ligand. Wherein, the temperature is preferably cooled to -120 ° C by mixing n-propanol with liquid nitrogen. This step (1) may also include the operation step of post-treatment after obtaining the monophosphine monobromo ligand. The post-treatment preferably includes extraction, drying and purification. The extraction is preferably performed by extracting the reaction solution with an extractant to obtain an organic layer. The extractant is selected from acetone and dichloromethane, preferably dichloromethane. Drying is preferably performed by drying the organic layer with a desiccant to remove moisture. The desiccant is not specifically limited in the present invention, such as anhydrous sodium sulfate. Purification is preferably performed by column chromatography on the dried organic layer, and the eluent for column chromatography is petroleum ether solvent.

[0068] Step (2), adding phenylphosphine dichloride to the reaction solution of the monophosphine and monobromine ligand at -78°C to obtain a fluorine-containing tridentate phosphine ligand;

[0069] Step (3), adding the obtained fluorine-containing tridentate phosphine ligand and CuI to a mixed solvent, reacting at room temperature to obtain a reaction solution;

[0070] In step (3), the solvent is selected from amide solvents, such as N,N-dimethylformamide, N,N-dimethylacetamide, aromatic hydrocarbon solvents, such as toluene or xylene, and alkane solvents, such as dichloromethane, chloroform or acetonitrile. The preferred solvent is a mixed solvent of N,N-dimethylformamide and acetonitrile.

[0071] The volume ratio of the solvent N,N-dimethylformamide to acetonitrile is 1:(1-20), preferably 1:(4-8), preferably 1:(3-5).

[0072] The molar ratio of the fluorine-containing tridentate phosphine ligand to CuI is 1:(1-12), preferably 1:(2-8), more preferably 1:(4-6), and most preferably 1:6.

[0073] The present invention provides an application of the multi-nuclear copper cluster complex guest material synthesized based on the fluorine-containing tridentate phosphine ligand unit in an electroluminescent device, especially as a light-emitting layer.

[0074] The present invention also provides an electroluminescent device prepared by using the multi-nuclear copper cluster complex guest material synthesized based on the fluorine-containing tridentate phosphine ligand unit.

[0075] In the present invention, the electroluminescent device includes a substrate layer, a conductive anode layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer and a cathode conductive layer.

[0076] The method for preparing the electroluminescent device provided by the present invention specifically comprises the following steps:

[0077] 1. preparing a conductive anode layer;

[0078] The plastic substrate cleaned with deionized water was placed in a vacuum evaporation apparatus with a vacuum degree of 1×10 -6 mbar, and the evaporation rate was set to 0.1 nm s -1 , on a glass or plastic substrate, an anode conductive layer with a thickness of 10 nm is deposited by evaporating indium tin oxide (ITO);

[0079] 2. preparing a hole injection layer;

[0080] MoO3, a hole injection layer material, is evaporated on the anode conductive layer to obtain a hole injection layer with a thickness of 6 nm;

[0081] 3. Preparation of hole transport layer;

[0082] The hole transport layer material TAPC is evaporated on the hole injection layer to obtain a hole transport layer with a thickness of 50 nm;

[0083] 4. preparing a light-emitting layer;

[0084] A mixture of a multi-nuclear copper cluster complex guest material synthesized based on a fluorine-containing tridentate phosphine ligand unit and a host material mCP was evaporated on the hole transport layer to a thickness of 20 nm.

[0085] 5. preparing an electron transport layer;

[0086] Evaporate the electron transport layer material TPBi on the light-emitting layer to form an electron transport layer with a thickness of 50nm;

[0087] 6. Preparation of electron injection layer;

[0088] The electron injection layer material LiF is evaporated on the electron transport layer to form an electron injection layer with a thickness of 1 nm;

[0089] 7. preparing a cathode conductive layer;

[0090] A cathode conductive layer with a thickness of 100 nm and a metal material is evaporated on the electron injection layer to obtain an electroluminescent device. The metal in step seven is aluminum.

[0091] The vapor-deposited electroluminescent device prepared from the multi-nuclear copper complex guest material provided by the present invention reduces the turn-on voltage to below 3.5V and has good photoluminescent performance. At the same time, it improves the luminous efficiency and brightness of the organic electroluminescent material, and can prepare an organic electroluminescent diode with excellent performance.

[0092] The technical solution of the present invention is described in detail below with reference to specific embodiments.

[0093] Example 1

[0094] In Ar, p-fluoro-o-dibromobenzene 10mmol was dissolved in anhydrous ether 50mL and cooled to -120 ℃. Then, n-butyl lithium 10mmol was added dropwise under agitation. Then, diphenylphosphine chloride 10mmol was added dropwise. The cold bath was removed and the reaction mixture was stirred for another 16 hours. Then, the reaction was quenched with water (50mL). The mixture was extracted with dichloromethane. The organic layers were combined and dried with anhydrous Na2SO4, and the solvent was removed in vacuo. Purification by flash column chromatography, eluent was PE, and monophosphine monobromine ligand was obtained.

[0095] In Ar, 10 mmol of the monophosphine monobromine ligand was dissolved in 50 mL of tetrahydrofuran and cooled to -78 ° C. Then, 10 mmol of n-butyl lithium was added dropwise under stirring. Then, 5 mmol of phenylphosphine dichloride was added dropwise. The cold bath was removed and the reaction mixture was stirred for another 16 hours. The reaction was then quenched with water (50 mL). The mixture was extracted with dichloromethane. The organic layers were combined and dried over anhydrous Na2SO4, and the solvent was removed in vacuo. Purification by flash column chromatography with DCM:PE (1:5) as the eluent gave a fluorinated tridentate phosphine ligand.

[0096] In the presence of Ar, 1 mmol of the obtained ligand and 6 mmol of CuI were dissolved in 1 mL of N,N-dimethylformamide and 5 mL of acetonitrile and stirred at room temperature for 15 hours. The solvent was evaporated to obtain a crude complex, which was then recrystallized from a dichloromethane / n-hexane solution to obtain yellow crystals 4FTTPPCu6I6, which is compound (I).

[0097] The molecular formula of compound (I) is C 85 H 58 P6F8Cu6I6 was tested by nuclear magnetic resonance hydrogen spectrometer, and the data were as follows: 1H NMR (400MHz, CDCl3) δ7.85 (s, 4H), 7.53 (s, 2H), 7.40 (t, J = 7.3Hz, 2H), 7.36-7.23 (m, 11H), 7.20 ( t,J=7.3Hz,2H),7.13(d,J=3.5Hz,2H),7.03(t,J=7.5Hz,4H),6.92(t,J=8.4Hz,2H),6.68(s,4H).

[0098] The obtained compound (I) was tested by UV spectrum and fluorescence spectrum. The test spectrum is as follows Figure 1 Its single crystal structure is shown as Figure 23 shown.

[0099] An electroluminescent device is prepared using the obtained mixture of compound (I) and mCP as a light-emitting layer material, as follows:

[0100] 1. preparing a conductive anode layer;

[0101] The plastic substrate cleaned with deionized water was placed in a vacuum evaporation apparatus with a vacuum degree of 1×10 -6 mbar, and the evaporation rate was set to 0.1 nm s -1 , on a glass or plastic substrate, an anode conductive layer with a thickness of 10 nm is deposited by evaporating indium tin oxide (ITO);

[0102] 2. preparing a hole injection layer;

[0103] MoO3, a hole injection layer material, is evaporated on the anode conductive layer to obtain a hole injection layer with a thickness of 6 nm;

[0104] 3. Preparation of hole transport layer;

[0105] The hole transport layer material TAPC is evaporated on the hole injection layer to obtain a hole transport layer with a thickness of 50 nm;

[0106] 4. preparing a light-emitting layer;

[0107] On the hole transport layer, a mixture of tridentate phosphine-coordinated hexanuclear copper cluster complex electroluminescent dye and host material mCP was evaporated to a thickness of 20 nm.

[0108] 5. preparing an electron transport layer;

[0109] Evaporate the electron transport layer material TPBi on the light-emitting layer to form an electron transport layer with a thickness of 50nm;

[0110] 6. Preparation of electron injection layer;

[0111] The electron injection layer material LiF is evaporated on the electron transport layer to form an electron injection layer with a thickness of 1 nm;

[0112] 7. preparing a cathode conductive layer;

[0113] A cathode conductive layer with a thickness of 100 nm and a metal material is evaporated on the electron injection layer to obtain an electroluminescent device. The metal in step seven is aluminum.

[0114] The structure of the electroluminescent device in this embodiment is: ITO / MoO3 (6 nm) / TAPC (50 nm) / mCP:4FTTPPCu6I6 (20 nm) / TPBi (50 nm) / LiF (1 nm) / Al.

[0115] The voltage-brightness relationship curve, voltage-current density relationship curve, electroluminescence spectrum, brightness-current efficiency relationship curve, brightness-power efficiency relationship curve and brightness-external quantum efficiency relationship curve of the electroluminescent device are as follows: Figure 3-4 shown.

[0116] Example 2

[0117] In Ar, p-fluoro-o-dibromobenzene 10mmol was dissolved in anhydrous ether 50mL and cooled to -120 ℃. Then, n-butyl lithium 10mmol was added dropwise under stirring. Then, diphenylphosphine chloride 10mmol was added dropwise. The cold bath was removed and the reaction mixture was stirred for another 16 hours. Then, the reaction was quenched with water (50mL). The mixture was extracted with dichloromethane. The organic layers were combined and dried over anhydrous Na2SO4. The solvent was removed in vacuo. Purification by flash column chromatography, eluent being PE, gave monophosphine monobromine ligands.

[0118] In Ar, 10 mmol of the monophosphine monobromine ligand was dissolved in 50 mL of tetrahydrofuran and cooled to -78 ° C. Then, 10 mmol of n-butyl lithium was added dropwise under stirring. Then, 5 mmol of phenylphosphine dichloride was added dropwise. The cold bath was removed and the reaction mixture was stirred for another 16 hours. The reaction was then quenched with water (50 mL). The mixture was extracted with dichloromethane. The organic layers were combined and dried over anhydrous Na2SO4. The solvent was removed in vacuo. Purification by flash column chromatography with DCM:PE (1:5) as the eluent gave a fluorinated tridentate phosphine ligand.

[0119] In the presence of Ar, 1 mmol of the obtained ligand and 6 mmol of CuI were dissolved in 1 mL of N,N-dimethylformamide and 5 mL of acetonitrile and stirred at room temperature for 15 hours. The solvent was evaporated to obtain a crude complex, which was then recrystallized from a dichloromethane / n-hexane solution to obtain yellow crystals 5FTTPPCu6I6, compound (II).

[0120] The molecular formula of compound (II) is C 85 H 56 P6F 10Cu6I6 was tested by nuclear magnetic resonance hydrogen spectrometer, and the data were as follows: 1 H NMR (400MHz, CDCl3) δ7.79 (dd, J=10.4, 6.7Hz, 8H), 7.39-7.27 (m, 24H), 7.18 (t ,J=7.5Hz,8H),7.00(t,J=8.0Hz,4H),6.94-6.87(m,4H),6.84(t,J=8.5Hz,8H).

[0121] The obtained compound (II) was tested by UV spectrum and fluorescence spectrum. The test spectrum was as follows: Figure 1 Its single crystal structure is shown as Figure 24 shown.

[0122] An electroluminescent device was prepared using the obtained mixture of compound (II) and mCP as the light-emitting layer material. The method was the same as the method for preparing the electroluminescent device in Example 1, except that the mixture of compound (II) and mCP obtained in Example 2 was used as the light-emitting layer material.

[0123] The structure of the electroluminescent device in this embodiment is: ITO / MoO3 (6 nm) / TAPC (50 nm) / mCP:5FTTPPCu6I6 (20 nm) / TPBi (50 nm) / LiF (1 nm) / Al.

[0124] The voltage-brightness relationship curve, voltage-current density relationship curve, electroluminescence spectrum, brightness-current efficiency relationship curve, brightness-power efficiency relationship curve and brightness-external quantum efficiency relationship curve of the electroluminescent device are as follows: Figure 5-6 shown.

[0125] Example 3

[0126] In Ar, p-fluoro-o-dibromobenzene 10mmol was dissolved in anhydrous ether 50mL and cooled to -120 ℃. Then, n-butyl lithium 10mmol was added dropwise under agitation. Then, diphenylphosphine chloride 10mmol was added dropwise. The cold bath was removed and the reaction mixture was stirred for another 16 hours. Then, the reaction was quenched with water (50mL). The mixture was extracted with dichloromethane. The organic layers were combined and dried with anhydrous Na2SO4, and the solvent was removed in vacuo. Purification by flash column chromatography, eluent was PE, and monophosphine monobromine ligand was obtained.

[0127] In Ar, 10 mmol of the monophosphine monobromine ligand was dissolved in 50 mL of tetrahydrofuran and cooled to -78 ° C. Then, 10 mmol of n-butyl lithium was added dropwise under stirring. Then, 5 mmol of phenylphosphine dichloride was added dropwise. The cold bath was removed and the reaction mixture was stirred for another 16 hours. The reaction was then quenched with water (50 mL). The mixture was extracted with dichloromethane. The organic layers were combined and dried over anhydrous Na2SO4. The solvent was removed in vacuo. Purification by flash column chromatography with DCM:PE (1:5) as the eluent gave a fluorinated tridentate phosphine ligand.

[0128] In the presence of Ar, 1 mmol of the obtained fluorinated tridentate phosphine ligand and 1 mmol of triphenylphosphine were dissolved with 6 mmol of CuI in 1 mL of N,N-dimethylformamide and 5 mL of acetonitrile and stirred at room temperature for 15 hours. The solvent was evaporated to obtain a crude complex, which was then recrystallized from a dichloromethane / n-hexane solution to obtain yellow crystalline FTTPP-TPP-Cu3I3, compound (III).

[0129] The molecular formula of compound (III) is C 60 H 47 P4FCu3I3, and tested it with a hydrogen nuclear magnetic resonance spectrometer, the data is: 1 H NMR (400MHz, CDCl3) δ7.85 (s, 4H), 7.53 (s, 2H), 7.40 (t, J = 7.3Hz, 8H), 7.36-7.23 (m, 14H), 7.20 ( t,J=7.3Hz,2H),7.13(d,J=3.5Hz,8H),7.03(t,J=7.5Hz,4H),6.92(t,J=8.4Hz,2H),6.68(s,4H).

[0130] The obtained compound (III) was tested by UV spectrum and fluorescence spectrum. The test spectrum is as follows Figure 2 Its H NMR spectrum Figure 27 shown.

[0131] An electroluminescent device was prepared using the obtained mixture of compound (III) and mCP as the light-emitting layer material. The method was the same as the method for preparing the electroluminescent device in Example 1, except that the mixture of compound (III) and mCP obtained in Example 3 was used as the light-emitting layer material.

[0132] The structure of the electroluminescent device in this embodiment is: ITO / MoO3 (6 nm) / TAPC (50 nm) / mCP:FTTPP-TPP-Cu3I3 (20 nm) / TPBi (50 nm) / LiF (1 nm) / Al.

[0133] The voltage-brightness relationship curve, voltage-current density relationship curve, electroluminescence spectrum, brightness-current efficiency relationship curve, brightness-power efficiency relationship curve and brightness-external quantum efficiency relationship curve of the electroluminescent device are as follows: Figure 7-8 shown.

[0134] Example 4

[0135] In Ar, p-fluoro-o-dibromobenzene 10mmol was dissolved in anhydrous ether 50mL and cooled to -120 ℃. Then, n-butyl lithium 10mmol was added dropwise under agitation. Then, diphenylphosphine chloride 10mmol was added dropwise. The cold bath was removed and the reaction mixture was stirred for another 16 hours. Then, the reaction was quenched with water (50mL). The mixture was extracted with dichloromethane. The organic layers were combined and dried with anhydrous Na2SO4, and the solvent was removed in vacuo. Purification by flash column chromatography, eluent was PE, and monophosphine monobromine ligand was obtained.

[0136] In Ar, 10 mmol of the monophosphine monobromine ligand was dissolved in 50 mL of tetrahydrofuran and cooled to -78 ° C. Then, 10 mmol of n-butyl lithium was added dropwise under stirring. Then, 5 mmol of phenylphosphine dichloride was added dropwise. The cold bath was removed and the reaction mixture was stirred for another 16 hours. The reaction was then quenched with water (50 mL). The mixture was extracted with dichloromethane. The organic layers were combined and dried over anhydrous Na2SO4. The solvent was removed in vacuo. Purification by flash column chromatography with DCM:PE (1:5) as the eluent gave a fluorinated tridentate phosphine ligand.

[0137] In the presence of Ar, 1 mmol of the obtained ligand and 1 mmol of triphenylphosphine were dissolved with 6 mmol of CuI in 1 mL of N,N-dimethylformamide and 5 mL of acetonitrile and stirred at room temperature for 15 hours. The solvent was evaporated to obtain a crude complex, which was then recrystallized from a dichloromethane / n-hexane solution to give yellow crystals of 4FTTPP-TPP-Cu3I3, compound (IV).

[0138] The molecular formula of compound (IV) is C 60 H 44 P4F4Cu3I3 was tested by nuclear magnetic resonance hydrogen spectrometer, and the data were as follows: 1 H NMR (400MHz, CDCl3) δ7.79 (dd, J=10.4, 6.7Hz, 4H), 7.39-7.27 (m, 17H), 7.18 (t, J=7.5 Hz,10H),7.00(t,J=8.0Hz,8H),6.94-6.87(m,2H),6.84(t,J=8.5Hz,4H).

[0139] The obtained compound (Ⅳ) was tested by UV spectrum and fluorescence spectrum. The test spectrum is as follows Figure 2Its single crystal structure is shown as Figure 25 shown.

[0140] An electroluminescent device is prepared using the obtained mixture of compound (IV) and mCP as the light-emitting layer material. The method for preparing an electroluminescent device is the same as the method for preparing the electroluminescent device in Example 1, except that the mixture of compound (III) and mCP obtained in Example 4 is used as the light-emitting layer material.

[0141] The structure of the electroluminescent device in this embodiment is: ITO / MoO3 (6 nm) / TAPC (50 nm) / mCP:4FTTPP-TPP-Cu3I3 (20 nm) / TPBi (50 nm) / LiF (1 nm) / Al.

[0142] The voltage-brightness relationship curve, voltage-current density relationship curve, electroluminescence spectrum, brightness-current efficiency relationship curve, brightness-power efficiency relationship curve and brightness-external quantum efficiency relationship curve of the electroluminescent device are as follows: Figure 9-10 shown.

[0143] Example 5

[0144] In Ar, p-fluoro-o-dibromobenzene 10mmol was dissolved in anhydrous ether 50mL and cooled to -120 ℃. Then, n-butyl lithium 10mmol was added dropwise under agitation. Then, diphenylphosphine chloride 10mmol was added dropwise. The cold bath was removed and the reaction mixture was stirred for another 16 hours. Then, the reaction was quenched with water (50mL). The mixture was extracted with dichloromethane. The organic layers were combined and dried with anhydrous Na2SO4, and the solvent was removed in vacuo. Purification by flash column chromatography, eluent was PE, and monophosphine monobromine ligand was obtained.

[0145] In Ar, 10 mmol of the monophosphine monobromine ligand was dissolved in 50 mL of tetrahydrofuran and cooled to -78 ° C. Then, 10 mmol of n-butyl lithium was added dropwise under stirring. Then, 5 mmol of phenylphosphine dichloride was added dropwise. The cold bath was removed and the reaction mixture was stirred for another 16 hours. The reaction was then quenched with water (50 mL). The mixture was extracted with dichloromethane. The organic layers were combined and dried over anhydrous Na2SO4. The solvent was removed in vacuo. Purification by flash column chromatography with DCM:PE (1:5) as the eluent gave a fluorinated tridentate phosphine ligand.

[0146] In the presence of Ar, 1 mmol of the obtained ligand and 1 mmol of triphenylphosphine were dissolved with 6 mmol of CuI in 1 mL of N,N-dimethylformamide and 5 mL of acetonitrile and stirred at room temperature for 15 hours. The solvent was evaporated to obtain a crude complex, which was then recrystallized from a dichloromethane / n-hexane solution to yield yellow crystals of 5FTTPP-TPP-Cu3I3, compound (V).

[0147] The molecular formula of compound (V) is C 60 H 43 P4F5Cu3I3 was tested by nuclear magnetic resonance hydrogen spectrometer, and the data were as follows: 1 H NMR (400MHz, CDCl3) δ7.79 (dd, J=10.4, 6.7Hz, 4H), 7.39-7.27 (m, 16H), 7.18 (t, J=7.5 Hz,10H),7.00(t,J=8.0Hz,8H),6.94-6.87(m,2H),6.84(t,J=8.5Hz,4H).

[0148] The obtained compound (V) was tested by UV spectrum and fluorescence spectrum. The test spectrum is as follows: Figure 2 Its single crystal structure is shown as Figure 26 shown.

[0149] An electroluminescent device is prepared using the obtained mixture of compound (V) and mCP as the light-emitting layer material. The method is the same as the method for preparing the electroluminescent device in Example 1, except that the mixture of compound (V) and mCP obtained in Example 4 is used as the light-emitting layer material.

[0150] The structure of the electroluminescent device in this embodiment is: ITO / MoO3 (6 nm) / TAPC (50 nm) / mCP:5FTTPP-TPP-Cu3I3 (20 nm) / TPBi (50 nm) / LiF (1 nm) / Al.

[0151] The voltage-brightness relationship curve, voltage-current density relationship curve, electroluminescence spectrum, brightness-current efficiency relationship curve, brightness-power efficiency relationship curve and brightness-external quantum efficiency relationship curve of the electroluminescent device are as follows: Figure 11-12 shown.

[0152] Comparative Example: Electroluminescent devices were prepared using the obtained compounds (I)-(V) as light-emitting layer materials. The voltage-brightness relationship curve, voltage-current density relationship curve, electroluminescence spectrum, brightness-current efficiency relationship curve, brightness-power efficiency relationship curve, and brightness-external quantum efficiency relationship curve of the electroluminescent device are shown in FIG. Figure 13-22 shown.

[0153] The present invention has been described in detail above with reference to specific embodiments and / or exemplary examples and the accompanying drawings. However, these descriptions should not be construed as limiting the present invention. Those skilled in the art will appreciate that various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present invention without departing from the spirit and scope of the present invention, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A multi-nuclear copper cluster complex guest material synthesized based on a fluorine-containing tridentate phosphine ligand unit, characterized in that: The multi-nuclear copper cluster complex guest material is one of the following compounds I to V:

2. The multi-nuclear copper cluster complex guest material synthesized based on a fluorine-containing tridentate phosphine ligand unit according to claim 1, characterized in that: The multi-nuclear copper cluster complex guest material is a compound having the following structural formula: Wherein, R is the receptor F.

3. The method for preparing a multi-nuclear copper cluster complex guest material based on the synthesis of a fluorine-containing tridentate phosphine ligand unit according to claim 1 or 2, characterized in that: The monophosphine monobromo ligand is synthesized from o-dibromobenzene or p-fluoro-o-dibromobenzene with diphenylphosphine, and then reacted with phenylphosphine dichloride to form a fluorine-containing tridentate phosphine ligand, which is finally coordinated with cuprous iodide to prepare the product.

4. The method for preparing a multi-nuclear copper cluster complex guest material based on the synthesis of a fluorine-containing tridentate phosphine ligand unit according to claim 3, characterized in that: The specific steps include: Step (1), adding diphenylphosphine to o-dibromobenzene or p-fluoro-o-dibromobenzene compound to obtain a monophosphine monobromo ligand; Step (2), adding phenylphosphine dichloride to the monophosphine monobromine ligand prepared in step (1) to obtain a fluorine-containing tridentate phosphine ligand; Step (3), adding the fluorine-containing tridentate phosphine ligand obtained in step (2) and cuprous iodide to a solvent, reacting at room temperature to obtain a reaction solution; Step (4): post-treating the reaction solution to obtain a multi-nuclear copper cluster complex guest material.

5. The method for preparing a multi-nuclear copper cluster complex guest material based on the synthesis of a fluorine-containing tridentate phosphine ligand unit according to claim 4, characterized in that: The reaction temperatures of step (1) and step (2) are -120°C and -78°C, respectively.

6. The method for preparing a multi-nuclear copper cluster complex guest material based on the synthesis of a fluorine-containing tridentate phosphine ligand unit according to claim 3, characterized in that: The molar ratio of the fluorine-containing tridentate phosphine ligand to the cuprous iodide is 1:(1-12).

7. Use of the multinuclear copper cluster complex guest material synthesized based on the fluorine-containing tridentate phosphine ligand unit according to claim 1 or 2 in an electroluminescent device.

8. The use according to claim 7, characterized in that The multi-nuclear copper cluster complex guest material synthesized based on the fluorine-containing tridentate phosphine ligand unit serves as a light-emitting layer in the electroluminescent device.

9. An electroluminescent device, characterized in that The invention comprises a light-emitting layer, wherein the light-emitting layer comprises the multi-nuclear copper cluster complex guest material synthesized based on the fluorine-containing tridentate phosphine ligand unit according to claim 1 or 2.

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