A multifunctional organic aromatic amine semiconductor material and its light-emitting device application

Abstract

An organic semiconductor compound containing naphthalene spirofluorene aromatic amine has high heat resistance, stability, solubility, sublimation and good hole transport mobility. It is applied to organic light-emitting diodes to obtain high efficiency, long life stability improvement. The organic semiconductor compound has the following structural formula (I), wherein Ar1 and Ar2 only contain an aromatic amine to form a hole transport or blue light-emitting compound. #imgabs0#

Description

Technical Field

[0001] The invention relates to a novel organic aromatic amine semiconductor material and an organic electroluminescent device or an organic light-emitting diode prepared therefrom, and in particular to an improved spirofluorene organic semiconductor, which is applied to an organic light-emitting diode (OLED) device to improve the application performance of a light-emitting OLED display device. Background Art

[0002] Organic semiconductor materials are new optoelectronic materials. Their large-scale research originated in 1977 when Hideki Shirakawa, A. Heeger and A. McDiamid jointly discovered doped polyacetylene with conductivity up to the copper level. Subsequently, in 1987, C. Tang et al. of Kodak invented organic small molecule light-emitting diodes (OLEDs), and in 1990, R. Friend and A. Holmes of Cambridge University invented polymer light-emitting diodes P-OLEDs, and in 1998, S. Forrest and M. Thomson invented more efficient organic phosphorescent light-emitting diodes PHOLEDs. Due to the advantages of easy structural adjustment, diverse varieties, adjustable energy bands, and even low cost like plastic film processing, and the numerous applications of organic semiconductors in conductive films, electrostatic copying, photovoltaic solar cell applications, organic thin film transistor logic circuits, and organic light-emitting OLED flat panel displays and lighting, the three scientists Shirakawa-Heeger-McDiamid won the Nobel Prize in Chemistry in 2000.

[0003] As the next generation of flat panel display applications, organic electroluminescent semiconductor materials require: 1. high luminous efficiency; 2. excellent device stability; 3. suitable luminescent color; 4. excellent film processing. In principle, most conjugated organic molecules (including star emitters), conjugated polymers, and organic heavy metal complexes containing conjugated chromophore ligands have electroluminescent properties and are used in various types of light-emitting diodes, such as organic small molecule light-emitting diodes (OLEDs), polymer organic light-emitting diodes (POLEDs), and organic phosphorescent light-emitting diodes (PHOLEDs). Phosphorescent PHOLEDs use both singlet excited state (fluorescence) and triplet excited state (phosphorescence) luminescence mechanisms, and obviously have much higher luminous efficiency than small molecule OLEDs and polymer POLEDs. PHOLED manufacturing technology and excellent PHOLED materials are essential for achieving low-power OLED display and lighting. The quantum efficiency and luminous efficiency of PHOLED are 3 to 4 times that of fluorescent OLED materials, which also reduces the heat generated and increases the competitiveness of OLED display panels. This provides the possibility that OLED display or lighting will surpass LCD display and traditional light sources in general. Therefore, existing high-end OLED devices contain more or less phosphorescent OLED materials.

[0004] In OLED devices, charge injection is achieved by injecting holes from the anode after applying a positive voltage to the anode, and injecting electrons after applying a negative voltage to the cathode. The electrons pass through the electron transport layer and the hole transfer layer respectively, and enter the bulk material of the emission layer at the same time. The electrons eventually enter the lowest unoccupied molecular orbital (LUMO) of the luminescent dopant, and the holes enter the highest occupied molecular orbital (HOMO) of the luminescent dopant to form excited luminescent dopant molecules (exciton state). After the exciton state returns to the ground state, it is accompanied by the emission of light energy, and the wavelength of the emitted light energy corresponds to the energy gap (HOMO-LUMO energy level difference) of the luminescent molecule dopant.

[0005] There have been many reports of precious metal organic ligand complexes, which have enhanced the spin-orbit effect under the influence of precious metals, making the originally weak phosphorescence become very strong and present excellent phosphorescence emission. For example, the green-emitting tris(phenylpyridine)iridium(III) complex, referred to as Ir(PPY)3, has the structural formula:

[0006]

[0007] The improved efficiency and saturated green light materials are:

[0008]

[0009] FirPic, which emits blue light, has the following structural formula:

[0010]

[0011] The main ligand 4,6-difluorophenylpyridine dominates the emission color.

[0012] Ir(mphmq)2(tmd) that emits red light has the following structure:

[0013]

[0014] Yellow emitting compounds such as:

[0015]

[0016] It has PL=560nm (Chem. Mater. 2004, 16, 2480-2488).

[0017] Phosphorescent OLED materials are composed of organic luminophores with certain conjugation as bidentate chelate ligands, which form cyclometal-ligand complexes with metal elements. Under high-energy light (such as ultraviolet light excitation) or charge injection (electrical excitation), the cyclometal-ligand charge transfer (MLCT) becomes an exciton, and then returns to the ground state to cause light emission. Metal iridium compound phosphorescent materials generally form iridium 3 ligand complexes with chelated homogeneous ligands containing N atoms and Ir, or use one or two chelated auxiliary ligands with shorter emission wavelengths, and form hybrid (hybride or heteroleptic dopants) complex luminescent compounds with two or one main ligand with longer emission wavelengths and precious metal iridium. Due to the natural transfer effect of emission wavelength from high energy (or short wavelength) to low energy (or long wavelength), under light excitation or electrical excitation conditions, hybrid or heteroleptic metal complex materials eventually show the emission wavelength of the main ligand. Therefore, in a heteroleptic iridium complex, the final color and performance are generally determined by the ligand with lower energy and longer emission wavelength as the main ligand, while other non-coloring ligands are auxiliary ligands. As auxiliary ligands, acetylacetone or its derivatives have been successfully used in many red light organometallic luminescent materials (C.Xia, et al, 10,038,151) and yellow light organometallic luminescent materials (PLTBoudreault, et al), and higher efficiency OLED devices are obtained than the original three-ligand organometallic luminescent materials, but the device working life is also shortened accordingly.

[0018] In order to increase the service life and obtain OLEDs with high luminous efficiency and full color gamut, many new structural organic semiconductor materials and OLED device applications emerge in an endless stream. Aromatic amine organic semiconductors have semiconductor properties due to the participation of nitrogen atom lone pair electrons in bonding aromatic heterocyclic conjugation, especially due to good hole injection and transport performance, they are used in OLED device hole injection and transport layers. After combining with developed conjugated chromophores, such as diarylamine styrene and diarylamine pyrene (pyrene), they are still widely used organic blue luminescent compounds. Document WO2012034627 uses spirofluorene structural units to obtain organic aromatic amine hole transport materials with improved performance. In recent years, studies have shown that in order to increase the conjugation of organic semiconductors, documents (WO2010038956, CWLee, etc.) disclose the use of spirofluorene methods to form coplanar units of naphthalene and various fused rings such as naphthalene, anthracene, phenanthrene, pyrene, etc., to obtain main materials, aromatic amines and other compounds, which are applied to blue light OLED devices to improve service life. The document (KR1020120112611) discloses the use of spirofluorene to form coplanar units of naphthalene and benzene rings, which are bonded with aromatic amines to obtain organic diaromatic amine blue light compounds, which have improved luminous efficiency compared to styrene aromatic amine compounds. Similarly, the document (US201710321118) discloses the use of spironaphthene to promote the coplanarity of conjugated benzene rings to obtain a blue light host material with improved efficiency. Compared with LED light-emitting diodes, organic OLED light-emitting diodes have energy-saving, eye protection, and flexible display and lighting-specific properties, but there is still a gap in luminous efficiency and lifespan, and further improvement is still needed.

[0019] In order to obtain efficient organic OLEDs, it is usually necessary to add an electron injection and electron transport layer between the light-emitting layer and the cathode, and a hole injection and hole transport layer between the light-emitting layer and the anode, so as to achieve a balance of electrons and holes in the light-emitting layer. The hole transport layer material usually has a high HOMO-highest occupied orbital energy level, such as aromatic amine organic semiconductors of various structures, but these materials generally have low glass transition temperatures or are easy to crystallize, which affects the long-term life of the device. Therefore, it is imperative to develop better aromatic amine organic semiconductor materials. Summary of the invention

[0020] Ideal organic molecular hole transport materials have excellent thermal stability, film forming properties and film morphology stability, high highest occupied molecular orbital HOMO energy level and good hole mobility. High glass transition temperature is conducive to improving film morphology stability, and high HOMO is conducive to hole injection. The mobility of holes is often controlled by the effective conjugation length of organic compounds. The coplanarity between different units in aromatic heterocyclic amine organic semiconductor molecules controls the effective conjugation length, which is particularly important, but good coplanarity also brings the disadvantages of easy crystallization and difficulty in evaporation film formation, affecting the life of the device. The use of benzylidene has been applied in hole transport (US patent application 2014013866) and electron transport (US patent 8679647). The use of naphthylspirofluorene structure is conducive to increasing the effective conjugated molecules while possibly avoiding the problem of easy crystallization of molecules. Table 1 lists the comparison of the naphthalene units of the two spirofluorene structures. From the molecular structure, A containing naphthalene-naphthalene units should have better conjugation than B containing naphthalene-benzene units. This may be the main consideration of the literature (WO2010038956, CW Lee, etc.) using the spirofluorene method to form a more developed structural unit composed of naphthalene and various fused rings such as naphthalene, anthracene, phenanthrene, pyrene, etc., to obtain OLED application materials. However, the comparison of 3D spatial configurations shows that the two naphthalene rings in the A unit are not completely coplanar, while the naphthalene-benzene in the B unit is completely coplanar and perpendicular to the bonded spirofluorene, so the B unit is likely to obtain a better effective conjugation length and become a hole transport material unit with improved performance.

[0021] Table 1: Comparison of two structural units

[0022]

[0023] Therefore, the present invention adopts the spirofluorene-bonded naphthalene-benzene unit B as a primitive to provide an organic semiconductor compound having the following general structural formula:

[0024]

[0025] It is characterized in that R1, R2, R3, and R4 can each be selected from: H, D, phenyl, an alkyl group with less than 15 carbon atoms, and a cycloalkyl group with less than 15 carbon atoms; optionally, it can also contain a crosslinking group to obtain solution film-forming properties and can obtain crosslinking after film formation;

[0026] Ar1 and Ar2 are independently selected from H atoms and contain at least one aromatic amine donor unit, and the aromatic amine donor unit may contain a unit with less than 80 carbon atoms.

[0027] There are many structures that can satisfy the general formula (I). In one case, the structure suitable for the present invention contains a single aromatic amine, and typical examples include but are not limited to the following structural formula (Table 2):

[0028] Table 2: Examples of structural formulas containing single aromatic amines suitable for the present invention

[0029]

[0030]

[0031]

[0032] In another embodiment, compound (I) further comprises a compound having the following structural formula (Table 3):

[0033] Table 3: Examples of structural formulas suitable for the present invention

[0034]

[0035]

[0036] According to the scope of the general formula (I) described in the present invention, many different structures can be formed. Ar1 and Ar2 only contain mono-aromatic amine, which is beneficial to control the molecular weight so that it does not become too large and cause difficulties in evaporation film formation. Mono-aromatic amine is also beneficial for simple synthesis and preparation, easy control, and easy purification, thus bringing cost advantages and improving the application performance of OLED devices. The general method for synthesizing and preparing organic aromatic amine semiconductor compounds described in this patent can be obtained in a variety of ways. A typical multi-step reaction is shown below:

[0037]

[0038] According to the above reaction formula, each unilateral halide 6a, 7a can be prepared, wherein R1 can be H or other alkyl, aryl, or aromatic hetero group. Each halide can be obtained by Bulkward carbon-nitrogen coupling reaction or Ullmann reaction to obtain aromatic amine compounds. A reaction synthesis example is as follows:

[0039]

[0040] The organic aromatic amine semiconductor material of the present invention is used relative to the general benzene-based spirofluorene organic semiconductor, and the spirofluorene bonding naphthalene-benzene characteristics make the molecule have better coplanarity and more developed conjugation, thereby improving the effective conjugation length and improving the hole transport material injection and mobility, and applying OLED devices to improve performance, reduce driving voltage, and increase device life. Relative to the benzene-benzene molecules (CN201610076386) bonded by spirofluorene, the use of naphthalene can also increase the glass transition temperature of the molecule, which is more conducive to forming a film with stable morphology and increasing the life of the OLED device. Relative to general aromatic amine organic semiconductors, the bonding of spirofluorene can reduce the interaction between molecules and improve the solubility and easy advantages of sublimation evaporation, which is helpful to obtain high-purity materials. In addition, the bonding of naphthalene spirofluorene and its vertical geometric space configuration are also helpful to obtain molecular film materials that are not easy to crystallize and stabilize the film morphology. As a small molecule OLED application material, it is necessary to consider the higher glass transition temperature required to maintain the ideal morphological stability, which is generally higher than 120°C, but at the same time it can be easily evaporated to meet the film formation requirements, so as not to bring the risk of material decomposition during the purification and evaporation process due to the evaporation temperature being close to the thermal decomposition temperature. The use of unilateral aromatic amines in this patent can obviously avoid the disadvantages of difficult synthesis and limited molecular structure selection brought by bilateral aromatic amine molecules, such as the organic blue light compounds disclosed in patent KR1020140046304. In addition, unilateral aromatic amines are also conducive to obtaining multifunctional materials, with the ability to select organic blue luminescent groups with larger molecular weights and bipolar chromophores, thereby giving the material the function of hole transport, bipolar host material, and high-efficiency blue luminescence characteristics.

[0041] The organic compound semiconductor materials described in Tables 2 and 3 are generally suitable for vacuum evaporation film formation. Recently, the use of inkjet printing for organic OLED displays in large-screen TVs has shown some advantages. Some or all of the functional materials in the organic light-emitting diodes are connected with cross-linking groups, such as vinyl, acrylate or trifluorovinyl. On the one hand, it increases solubility. On the other hand, after the solution film-forming solvent is dried, under heating conditions, the molecules form an insoluble and infusible macromolecular network structure through chemical cross-linking reactions, which increases the dimensional stability of the film. Moreover, another layer of organic film can be coated on its surface again by a solution method to prepare advanced multilayer OLED devices. The scope described in this patent can be expanded to soluble and cross-linkable organic semiconductors with the following general structural formula (II):

[0042]

[0043] It is characterized in that R1, R2, R3, and R4 can each be selected from H, D, phenyl, aromatic hetero with less than 15 carbon atoms, alkyl with less than 15 carbon atoms, and cycloalkyl with less than 15 carbon atoms;

[0044] Ar1 and Ar2 are independently selected from H atoms, and include at least one aromatic amine having less than 80 donor carbon atoms;

[0045] The invention is characterized in that part or all of Ar1, Ar2, R3 and R4 contain crosslinking groups, and the crosslinking groups are selected from vinyl, acrylate or trifluorovinyl.

[0046] In the above scope, the cross-linkable compound hole transport material in the organic light-emitting diode includes but is not limited to the following compounds containing cross-linking groups of general formula III to VIII:

[0047]

[0048] The chemical bonding cross-linking groups increase the solubility on the one hand, and on the other hand, after the film-forming solvent of the solution is dried, under heating conditions, the molecules form an insoluble and infusible macromolecular network structure through chemical cross-linking reactions. For example, the organic semiconductor compound containing cross-linking groups is heated to 160 ℃ Or higher temperature, an insoluble cross-linked network structure is formed, as shown in reaction formula 3:

[0049]

[0050] or:

[0051] or:

[0052]

[0053] By using an organic semiconductor compound carrying a cross-linking group, it is convenient to use a solution to form a film, and then heat the film to make it insoluble and infusible, which is conducive to realizing a multi-layer thin film OLED device through solution molding, and obtaining a low-cost, continuous printing manufacturing OLED display screen. Specifically, the organic semiconductor aromatic amine material with a cross-linking group includes but is not limited to the following structure Table 4:

[0054] Table 4: Organic semiconductor aromatic amine materials with cross-linking function:

[0055]

[0056]

[0057] The organic semiconductors described in Table 4 additionally contain soluble and cross-linkable functional groups, and are particularly suitable for solution printing or spray coating, spin coating film forming processes. Their synthesis and preparation can be carried out by a variety of known methods, one of which is the following route (reaction formula 6):

[0058]

[0059] The present invention is more important in that the organic semiconductor is applied to a light-emitting device. Specifically, the present invention discloses an organic light-emitting diode, which is characterized in that the organic light-emitting diode is composed of the following parts:

[0060] (a) a cathode,

[0061] (b) an anode,

[0062] (c) A single or multi-layer organic semiconductor sandwiched between the cathode and the anode, characterized in that the chemical structure of the organic semiconductor is generally represented by the structural organic semiconductors described in (I) to (VIII).

[0063] In traditional organic light-emitting diode chips, transparent conductive glass or indium-tin oxide (ITO) is usually used, and a hole injection layer HIL is deposited on it, followed by a hole transport layer HTL, a light-emitting layer EML, an electron transport layer ETL, and an electron injection layer EIL. Finally, a metal layer, such as an aluminum metal layer, is added as the anode conductive and sealing layer. Figure 1 ) When ITO is positively charged and aluminum is negatively charged to a certain electric field, holes are injected from ITO through the HIL and transferred to the EML through the HTL, while electrons are injected from the EIL connected to aluminum and transferred to the EML through the ETL. Electrons and holes meet in the EML and recombine to form excitons, and then some excitons release energy in the form of light radiation and return to the ground state. The wavelength of light radiation is determined by the energy gap of the luminescent dopant in the EML layer.

[0064] According to the organic light emitting diode described in the scope of the present invention, the hole transport material in the organic light emitting diode contains the organic semiconductor compound of the present invention. When applied to an organic OLED device, it can be a blue light emitting device with a light emission wavelength of 440-465nm, or a green light emitting device with a light emission wavelength of 510-550nm; or a yellow light emitting device with a light emission wavelength of 551-580nm, or a red light emitting device with a light emission wavelength of 581-640nm.

[0065] To obtain efficient green and red OLEDs, triplet phosphorescent OLEDs are usually used, in which the emission layer contains phosphorescent luminescent materials, including but not limited to Ir(ppy)3 for green light, or Ir(Piq)3 as a red light dopant. The luminescent dopant is generally used in an amount of 2 to 15% of the luminescent (by weight) material, doped into a host material.

[0066]

[0067] As green and red phosphorescent OLEDs, any host material with a triplet energy level greater than 2.4 eV can be used as the luminescent material OLED of the present invention. The host material is commonly used to contain carbazole or aromatic amine structure materials. A commonly used host material is 4,4'-N,N'-dicarbazole-biphenyl (CBP):

[0068]

[0069] More advanced balanced electron-hole host materials include IPA-PCz and IPA-Ph-PCz (US20140225088):

[0070]

[0071] Or the BPBC host material with the following electronegativity:

[0072]

[0073] Or the auxiliary main material has the electrical conductive material DBPP:

[0074]

[0075] The auxiliary host material can also be the following electronegative material MCBP:

[0076]

[0077] In order to achieve excellent phosphorescent device performance, a hole injection layer may be optionally provided on the anode, such as a compound containing aromatic amine (Appl. Phys. Lett., 69, 2160 (1996), m-TDATA; or HATCN6.

[0078]

[0079] Similarly, a hole transport layer may be selected between the hole injection layer and the emission layer EML, such as the commonly used 4,4'-bis[N-(1-naphthyl)-N-phenylamino]biphenyl (α-NPD)

[0080]

[0081] In order to balance the injection of electrons and holes and improve the luminous efficiency, an electron transport material can be selected. Examples are 1,3,5-tris(1-phenyl-1H-benzimidazol-2-yl)benzene TPBi and BPhen, whose structures are:

[0082]

[0083] The electron injection layer can be a pure organic molecular material, or doped with another electronegative material, such as 8-hydroxylithium (Liq) and its N-type doped material. An electron injection layer is also commonly used between the electron transport layer and the cathode. The electron injection layer is usually a metal lithium with a low work function, a lithium salt such as LiF, or a compound thereof such as 8-hydroxylithium (Liq):

[0084]

[0085] Therefore, the OLED light-emitting device is a complex multi-layer structure. Figure 1 It is a typical structure, but not the only applicable structure. The total thickness of the organic semiconductor layer is 50-250 nanometers, preferably 80-180 nanometers.

[0086] According to the organic light-emitting diode described in the scope of this patent, the organic semiconductor compound contains aromatic amines, which have the function of easy hole injection and transport, and is suitable for use as a hole transport layer. Due to the presence of a naphthalene-benzene structure in the molecule, when combined with a blue luminescent group, the compound of the present invention has effective photoluminescence and electroluminescence properties, and the luminescent wavelength is in the blue light range of 420-470 nanometers. Therefore, the compound of the present invention can also be used in blue light OLED device applications as a luminescent dopant. In principle, the organic aromatic amine compounds described above all have certain luminescent properties, and are particularly suitable for efficient and stable luminescent blue dopant compounds including the following structures:

[0087]

[0088]

[0089] And cross-linkable blue luminescent materials:

[0090]

[0091]

[0092] In order to obtain a light-emitting diode with higher performance, the light-emitting layer may also contain an auxiliary host material that increases the electron or hole injection capability, that is, a mixed host material is used, wherein the ratio of the auxiliary host material to the main host material is 5-48%. The aromatic amine organic semiconductor material of the present invention can be used as an auxiliary host material in the light-emitting layer, especially containing a bipolar group, such as carbazole, carbazole substituents, benzofuran and the derivatives described above, including the following materials:

[0093]

[0094] And cross-linkable main auxiliary materials:

[0095]

[0096] Using OLED light-emitting devices, it can be used for flat screen displays, such as mobile phone screens, i-Pack screens, TV screens, computer screens, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0097] Figure 1 Schematic diagram of the structure of an organic light-emitting diode. DETAILED DESCRIPTION

[0098] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with examples. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0099] Example 1: Synthesis of Compound I-3

[0100] Prepared according to the general reaction route already described, the partial synthesis is as follows:

[0101] 1.1 Reaction conditions and ratios for preparing compound 3

[0102]

[0103]

[0104] Specifically, THF (560 mL) was added to a 1 L three-necked flask, K2CO3 (77 g) was dissolved in water (0.266 L), and then the K2CO3 solution was added to the reaction flask, the nitrogen was replaced once, and then 1,8-dibromonaphthalene 40 g, 4-chlorophenylboric acid 21.8 g, Pd (pph3) 41.6 g were added in sequence, the nitrogen was replaced twice, and after the reaction was completed under TLC monitoring, the temperature was lowered to room temperature, washed with water, separated, mixed with silica gel and passed through a column, concentrated, and dried to obtain product 3 (28 g, yield: 70%, HPLC: 81%).

[0105] 1.2 Reaction conditions and ratios for preparing compounds 5 and 6

[0106]

[0107] In a 500ml three-necked flask, 300ml of anhydrous THF was added, and then 30g of compound 3 was added, and nitrogen was replaced 3 times. The mixture was cooled to -70°C using an acetone dry ice system, and n-butyl lithium (concentration 2.5M, Shanghai Yetan Chemical) was slowly added dropwise, and stirred for 1h. 17.8g of 9-fluorenone was dissolved in 53ml of anhydrous THF, and the mixture was slowly added dropwise to the reaction flask. After the addition was complete, the mixture was gradually changed to room temperature and stirred for 17h. After the reaction was complete under TLC monitoring, a saturated NaHCO3 solution was slowly added to the reaction solution to quench the reaction, and DCM and water were added for extraction. The mixture was separated, concentrated, and passed through a column to obtain compound 5 (25g of oil, HPLC: 36%, yield 78%).

[0108] In a 500ml three-necked flask, add 250ml acetic acid and 4ml hydrochloric acid, then add 25g of oily compound 5 to the reaction flask and heat to 120°C. React for 15h, monitor by TLC, and after the reaction is complete, cool to room temperature, add DCM and water to the reaction solution, extract, concentrate, column, gradient elution, concentrate to a small amount, add PE, stir for 5min, filter, and dry to obtain the product compound 6a (6.2g, HPLC: 97.9%, yield: 72%, Mw = 401).

[0109] Following the similar operation as above, compound 6b was obtained (HPLC: 98%, yield 79%, Mw=366.5).

[0110] 1.3 Reaction conditions and ratios for preparing compound 7a

[0111]

[0112] Preparation reaction process of compound 7a: add 150 ml of dichloromethane to a 250 ml three-necked flask, then add 5.9 g of compound 6b, stir until dissolved, dissolve 2.36 g of liquid bromine (Shanghai Songyuan Chemical) in 14 ml of DCM, slowly add dropwise to the reaction flask, stir at room temperature for 17 hours, monitor by HPLC positioning, after the reaction is complete, add DCM and water to the reaction solution, wash with water 4 times, concentrate, and filter to obtain white solid compound 7a (6.5 g, HPLC: 97%, yield: 91%, Mw = 445.35).

[0113] 1.4. Preparation of Compound I-3

[0114]

[0115] Experimental conditions and ratios for the synthesis of intermediate I-3-1

[0116]

[0117] Experimental process: In a 500mL three-necked flask, add 230mL toluene, then add 23.0g 6a, 11.6g benzidine, 0.522g Pd(OAc)2, 1.27g DPPF, 8.27g NaOtBu, replace with nitrogen 3 times, react at 110℃ for 16h, monitor by TLC, cool down after the reaction, wash with water, pass through two silica columns, concentrate the organic phase, PE reverse precipitate, beat for 2h, dry and recrystallize from IPO to obtain 21.4g of white solid I-3-1 intermediate, Yield: 70%, HPLC: 99.5%

[0118] Experimental conditions and ratios for the synthesis of compound I-3

[0119]

[0120] Experimental process: In a 500mL three-necked flask, add 220mL toluene, then add 21.0g I-3-1`, 10.8g 2-bromo-9,9,-dimethylfluorene, 0.13g Pd(OAc)2, 0.464g TTBP, 9.46g NaOtBu, replace with nitrogen 3 times, react at 110℃ for 16h, monitor by TLC, cool down after the reaction, wash with water, pass through two silica columns, concentrate the organic phase, PE reverse precipitation, beat for 2h, dry and recrystallize from toluene to obtain 21.4g of white solid I-3 compound, Yield: 70%, HPLC: 99.5%; theoretical molecular formula C 56 H 39 The calculated molecular mass of N is 725.31, the Mass detection m / e=725.3; PL=415nm, UV absorption 358nm, energy gap Eg=2.9eV, and the DSC instrument detects the glass transition temperature Tg=143°C.

[0121] Example 2: Synthesis of other compounds:

[0122] Similarly, according to the above synthetic chemistry principles and general reaction formulas 1, 2, and 3, without violating the scope of the present invention, the following organic semiconductor material compounds were synthesized. The molecular weights and molecular fragments of the specific compounds listed were verified by mass spectrometry, and the specific summary is shown in Table 5 below:

[0123] Table 5: Compound synthesis and characterization

[0124]

[0125]

[0126]

[0127]

[0128] By using general organic chemical reactions, according to the above chemical principles and similar steps, the following cross-linkable aromatic amine organic semiconductor materials can be obtained.

[0129] Table 6: Synthesis and performance characterization of cross-linkable aromatic amine organic semiconductor materials

[0130]

[0131]

[0132] Example 4. Application example of hole transport material in OLED device (comparative device):

[0133] In a background vacuum up to 10 -5 The following device structure is used in the multi-source evaporation OLED preparation equipment of Pa: ITO / HATCN6 / HT / Host:5% luminescent dopant 5% / ET / LiF / Al, using different HT hole transport material OLED light emitting devices for comparison. The vacuum deposition speed of each organic layer and electrode is listed in Table 7.

[0134] Table 7: OLED device preparation conditions (doping wt concentration in the light-emitting layer 5%)

[0135] Material Deposition rate (angstroms / second) Thickness Control (Angstroms) Time required (seconds) <![CDATA[HIL:HATCN6]]> 0.5 50 100 HTL: Ref-HT 2.0 600 300 EML:Host / Dopant5% 1.5 300 200 ETL:BPhen 1.0 350 350 EIL:LiF 0.5 10 20 Al 5.6 1000 180

[0136] The known or common materials used in the experiment are as follows in Table 8:

[0137] Table 8: Known or common materials used in the experiments

[0138]

[0139] Example 5 Application example of the organic aromatic amine compound of this patent as a hole transport material in OLED device:

[0140] According to the preparation method of the OLED device described in Example 4, the following OLED device comparison table 9 is obtained using a transport material containing aromatic amine:

[0141] Table 9: Comparison of OLED devices obtained using transport materials containing aromatic amines

[0142]

[0143]

[0144] The above shows that relative to the reference device B0 blue light OLED, the HT compounds I-3, I-11, and I-23 described in the present invention have the advantage of extending the device life. Referring to the reference device G0 green light OLED, the HT compounds I-6, I-33, and I-46 described in the present invention have the advantage of extending the device life. Referring to the device R0 red light OLED, the HT compounds II-5, II-15, and II-24 described in the present invention have the advantage of extending the device life. It shows that the use of naphthalene-phenylspirofluorene aromatic amine analogs has the effect of increasing the life of OLED devices compared to previously reported phenylspirofluorene aromatic amine compounds.

[0145] Example 6. Application example of auxiliary main layer material in OLED device:

[0146] According to the preparation method of the OLED device described in Example 4, the aromatic amine compound material containing carbazole, carbazole derivatives or benzofuran groups described in the present invention can be used as a triplet red light and green light auxiliary host material to obtain improved device efficiency and working life. The results are as follows: OLED device comparison table 10:

[0147] Table 10: Comparison of OLED devices

[0148]

[0149] Comparing G0 and R0 devices, the use of I-20, I-31, and I-32 aromatic amine organic semiconductors containing carbazole as auxiliary materials for the main material can effectively reduce the operating voltage, improve the device's luminous efficiency, and extend its working life.

[0150] Example 6. Application example of blue light emitting material in OLED device:

[0151] According to the preparation method of the OLED device described in Example 4, the following OLED device comparison table 11 is obtained using a material containing aromatic amine:

[0152] Table 11: Comparison of OLED devices

[0153]

[0154] The above shows that compared with the reference device B0 blue light OLED, the compound II-19 described in the present invention is a unilateral substitution of the Ref-BD compound, showing a higher luminous efficiency (increased by 18%); the compounds I-3, I-11, and I-23 described in the present invention have the advantages of extending the device life and increasing the luminous efficiency.

[0155] Example 7: Cross-linkable aromatic amine organic semiconductor material is applied to the hole transport functional layer in solution-plated OLED device:

[0156] On a conductive glass ITO surface, after solvent and plasma cleaning, a PEDOT conductive polymer was solution-spin-coated as a hole injection layer HIL, and the crosslinkable compounds X-1, X-5, and X-9 of the present invention were used as solution spin-coated films as hole transport layers HTL. After heating to 160°C for 30 minutes under nitrogen, the film was cross-linked to form an infusible and insoluble HT layer; for other layers such as the main material / luminescent dopant green or red light, or blue light emitting layer, the comparative experiment was that the solution spin-coated HT layer was not heated to 160°C for 30 minutes under nitrogen, and the other steps were exactly the same. The results of the OLED device showed that the life of the OLED device after thermal crosslinking increased by 20%.

[0157] Example 8: Application of cross-linkable aromatic amine organic semiconductor in solution-coated OLED device and blue light emitting material:

[0158] On a conductive glass ITO surface, after solvent and plasma cleaning, a PEDOT conductive polymer is solution-spin-coated as a hole injection layer HIL, and a cross-linkable compound X-6 solution spin-coated film of the present invention is used as a hole transport layer HTL. After heating to 160°C for 30 minutes under nitrogen, the film is cross-linked to form an infusible and insoluble HT layer; a cross-linkable compound X-4 solution spin-coated film of the present invention is used as a hole transport electron blocking EB layer. After heating to 160°C for 30 minutes under nitrogen, the film is cross-linked to form an infusible and insoluble HTEB layer; a cross-linkable compound X-9 containing carbazole is selected as the main material, and a mixed solution of blue light dopants X-10 to X-15 (doping concentration 4% by weight) is spin-coated, and then heated to 160°C for 30 minutes under nitrogen to form an infusible and insoluble light-emitting layer EML; finally, in a background vacuum of 10 -5 In the multi-source evaporation OLED preparation equipment of Pa, the electron transport layer, electron injection layer and metal electrode Al layer were evaporated similarly to Example 4 to prepare OLED devices. The comparative experiment was that the solution was spin-coated with the EML layer without heating to 160°C for 30 minutes under nitrogen, and the other steps were exactly the same. The results of the OLED device showed that the life of the OLED device after thermal cross-linking increased by 16%.

[0159] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the technical content disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. An organic light emitting diode, the organic light emitting diode comprising the following parts: (a) a cathode, (b) an anode, (c) a single layer or multiple layers of organic semiconductor compounds sandwiched between the cathode and the anode, characterized in that the organic semiconductor compound is used as a hole transport layer material or as an auxiliary host material of the light-emitting layer, and the organic semiconductor compound comprises the following compounds:

2. The organic light emitting diode according to claim 1, characterized in that: The light-emitting layer contains the organic semiconductor compound as an auxiliary main material of the light-emitting layer, and the weight of the organic semiconductor compound in the light-emitting layer is 20-48%.

3. The organic light emitting diode according to claim 1, characterized in that: The organic semiconductor compound forms an organic light-emitting device functional layer through a solution film-forming process, and becomes an insoluble and infusible cross-linked network film after being heated and cross-linked.

4. An organic light emitting diode, the organic light emitting diode comprising the following parts: (a) a cathode, (b) an anode, (c) a single layer or multiple layers of organic semiconductor compound sandwiched between the cathode and the anode, characterized in that the organic semiconductor compound is a blue light-emitting material with an emission wavelength of 440-480 nm, and the organic semiconductor compound comprises the following compounds:

5. The organic light emitting diode according to claim 4, characterized in that: The luminescent layer contains the organic semiconductor compound as a blue luminescent material of the luminescent layer, and the weight of the organic semiconductor compound in the luminescent layer is 1-40%.

6. The organic light emitting diode according to claim 4, characterized in that: The organic semiconductor compound forms an organic light-emitting device functional layer through a solution film-forming process, and becomes an insoluble and infusible cross-linked network film after being heated and cross-linked.

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