Xanthene spiroazaanthrone organic electroluminescent material, preparation method and application thereof
Technical Field
The invention belongs to the field of organic electroluminescence, and particularly relates to a xanthene spiroazaanthrone organic electroluminescent material, and a preparation method and application thereof.
Background
Since 1987, Organic Light-Emitting Diodes (OLEDs) have become the next generation of flat panel display technology. The traditional organic fluorescent material can only emit light by utilizing 25 percent singlet excitons formed by electric excitation, and the internal quantum efficiency of the device is lowerAlthough the phosphorescence material enhances intersystem crossing due to strong spin-orbit coupling of heavy atom center, singlet excitons and triplet excitons formed by electric excitation can be effectively used for emitting light, and the internal quantum efficiency of the device reaches 100%, the phosphorescence material has the problems of high price, poor material stability, serious device efficiency roll-off and the like, and the application of the phosphorescence material in OLEDs is limited, and the Thermal Activation Delayed Fluorescence (TADF) material is a third generation organic luminescent material developed after organic fluorescent materials and organic phosphorescence materialsST) The triplet excitons may be converted to singlet excitons by intersystem crossing to emit light. This can make full use of singlet excitons and triplet excitons formed under electrical excitation, and the internal quantum efficiency of the device can reach 100%. Meanwhile, the material has controllable structure, stable property, low price and no need of precious metal, and has wide application prospect in the field of OLEDs.
In OLEDs, TADF materials are usually incorporated as a guest into a host to form a light-emitting layer, so as to overcome the low device performance caused by concentration quenching. Because the TADF material and the host material thereof are all pure organic molecules, the high identity in molecular structure and properties easily causes a quenching effect between host and guest molecules, which further increases the difficulty in developing the highly efficient TADF host material. In recent years, although many TADF host materials have appeared, the requirements for improving the performance of OLED devices and the market demand are far from being met, and therefore, it is important to develop TADF host materials with better performance.
Disclosure of Invention
The invention aims to solve the technical problem of providing a xanthene spiroazaanthrone organic electroluminescent material, and a preparation method and application thereof.
The technical scheme for solving the technical problems is as follows: a xanthene spiroazaanthrone organic electroluminescent material has a structural formula as follows:
wherein Ar is1、Ar2The same or different, each independently hydrogen, C6-C60 aryl, heteroaryl, or arylamine groups.
Further, Ar1、Ar2At different times, Ar1Is hydrogen, Ar2Is a C6-C60 aryl, heteroaryl or arylamine group.
Preferably, Ar1、Ar2Each independently is any one of the following groups:
wherein E represents a chemical bond linking site.
The compounds C01-C21 listed below are representative structures in keeping with the spirit and principles of the invention, and it is to be understood that the following structures are listed only for the purpose of better explaining the invention and are not intended to be limiting thereof.
The second purpose of the invention is to provide a preparation method of the xanthene spiroazaanthrone organic electroluminescent material, which comprises the following two methods:
carrying out C-N coupling reaction on the raw material I and Ar-H to prepare a target compound;
the reaction equation is as follows:
or the raw material II and Ar-Br are subjected to C-C coupling reaction to prepare a target compound;
the reaction equation is as follows:
and Ar is hydrogen, C6-C60 aryl, heteroaryl or arylamine.
The third purpose of the invention is to provide an application of the xanthene spiroazaanthrone organic electroluminescent material as a luminescent layer material in the field of manufacturing organic electroluminescent devices.
When in use, the prepared organic electroluminescent device generally comprises an ITO conductive glass substrate (anode), a hole transport layer (NPB-mCP), a luminescent layer (the material in the invention), an electron transport layer (BPhen), an electron injection Layer (LiF) and a cathode layer (Al) which are sequentially and upwards superposed. All functional layers are made by vacuum evaporation process. The molecular structural formula of the organic compound used in the device is shown as follows.
The invention has the beneficial effects that:
1. the compound takes xanthene spiroazaanthrone as a mother nucleus, the spiro structure has high spatial stereo effect, and the highly distorted configuration can effectively inhibit the interaction among all molecules possibly existing among objects, between a host and between the host and the object in a doped film, so that the quenching effect caused by collision is inhibited to the maximum extent.
2. The xanthene ring and the azaanthrone ring are connected through the spiro carbon, so that the conjugation degree of the xanthene ring and the azaanthrone ring can be effectively reduced, and the xanthene ring and the azaanthrone ring have proper HOMO and LUMO energy levels; by modifying the xanthene ring, the twisted structure of the xanthene ring and the azaanthrone ring can be further changed, the rigidity and asymmetry of molecules are enhanced, the rigid structure can effectively inhibit the relaxation of the structure, the stability of the material is enhanced, and the photoelectric property is improved; the asymmetric structure can greatly inhibit the intermolecular interaction and form a highly disordered molecular packing pattern in the solid film.
3. The compound can be applied to the preparation of OLED light-emitting devices and can obtain good device performance, and when the compound is used as a light-emitting layer material of the OLED light-emitting devices, the prepared devices have good photoelectric properties. The compound has good application effect in OLED luminescent devices and good industrialization prospect.
Drawings
FIG. 1 is a schematic view of the structure of an organic electroluminescent device according to the present invention;
in the figure, 1, an ITO conductive glass substrate; 2. a hole transport layer; 3. a light emitting layer; 4. an electron transport layer; 5. an electron injection layer; 6. a cathode layer.
Detailed Description
The principles and features of this invention are described below in conjunction with examples which are set forth to illustrate, but are not to be construed to limit the scope of the invention.
EXAMPLE 1 Synthesis of Compound C01
Under the protection of nitrogen, raw material II (1.53g, 2.5mmol), bromobenzene (0.86g, 5.5mmol), 80mL of toluene and 20mL of water are added into a 250mL three-necked bottle, and then catalyst tetrakis (triphenylphosphine) palladium (0.029g, 0.025mmol) and acid-binding agent potassium carbonate (1.04g, 7.5mmol) are added. And heating the system to reflux reaction for 8 hours, naturally cooling to 20-25 ℃, separating liquid, removing the solvent, and crystallizing the crude product by using toluene to obtain 1.12g of a target object C01 with the yield of 87.5%.
High resolution mass spectrum, ESI source, positive ion mode, molecular formula C37H23NO2Theoretical value 513.173, test value 513.173. Elemental analysis (C)37H23NO2) Theoretical value C: 86.53, H: 4.51, N: 2.73, O: 6.23. found value C: 86.53, H: 4.50, N: 2.74, O: 6.23.
EXAMPLE 2 Synthesis of Compound C05
Referring to example 1, the target product C05 was obtained in 76.6% yield.
High resolution mass spectrum, ESI source, positive ion mode, molecular formula C43H26N2O2Theoretical value 602.199, test value 602.199. Elemental analysis (C)43H26N2O2) Theoretical value C: 85.69, H: 4.35, N: 4.65, O: 5.31. found value C: 85.70, H: 4.34, N: 4.65, O: 5.31.
EXAMPLE 3 Synthesis of Compound C08
Referring to example 1, the target product C08 was obtained in 76.1% yield.
High resolution mass spectrum, ESI source, positive ion mode, molecular formula C41H25NO2Theoretical value 563.189, test value 563.181. Elemental analysis (C)41H25NO2) Theoretical value C: 87.37, H: 4.47, N: 2.49, O: ,5.68. Found value C: 87.37, H: 4.47, N: 2.49, O: 5.68.
EXAMPLE 4 Synthesis of Compound C13
Under the protection of nitrogen, mixing a raw material I (1.30g, 2.5mmol), carbazole (0.011g, 0.05mmol), a catalyst ligand tri-tert-butylphosphine tetrafluoroborate (0.026g, 0.1mmol) and an acid-binding agent sodium tert-butoxide (1.44g, 15mmol), heating the system to reflux reaction for 8 hours, naturally cooling to 20-25 ℃, adding 50mL of water to quench the reaction, separating liquid, removing the solvent, crystallizing the crude product with toluene to obtain 1.41g of a target product C13, wherein the yield is 81.5%.
High resolution mass spectrum, ESI source, positive ion mode, molecular formula C49H29N3O2Theoretical value 691.226, test value 691.227. Elemental analysis (C)49H29N3O2) Theoretical value C: 85.07, H: 4.23, N: 6.07, O: 4.63. found value C: 85.08, H: 4.22, N: 6.07, O: 4.63.
EXAMPLE 5 Synthesis of Compound C15
Referring to example 4, the target product C15 was obtained in 77.2% yield.
High resolution mass spectrum, ESI source, positive ion mode, molecular formula C49H27NO4Theoretical value 693.194, test value 693.193. Elemental analysis (C)49H27NO4) Theoretical value C: 84.83, H: 3.92, N: 2.02, O: 9.22. found value C: 84.83, H: 3.91, N: 2.03, O: 9.22.
EXAMPLE 6 Synthesis of Compound C16
Referring to example 4, the target product C16 was obtained in 71.6% yield.
High resolution mass spectrum, ESI source, positive ion mode, molecular formula C45H40N2O2Theoretical value 640.309, test value 640.309. Elemental analysis (C)45H40N2O2) Theoretical value C: 84.34, H: 6.29, N: 4.37, O: 4.99. found value C: 84.34, H: 6.30, N: 4.36, O: 4.99.
EXAMPLE 7 Synthesis of Compound C21
Referring to example 4, the target product C21 was obtained in 76.5% yield.
High resolution mass spectrum, ESI source, positive ion mode, molecular formula C46H32N2O2Theoretical value 644.246, test value 644.216. Elemental analysis (C)46H32N2O2) Theoretical value C: 85.69, H: 5.00, N: 4.34, O: 4.96. found value C: 85.70, H: 5.01, N: 4.33, O: 4.95.
application examples of the organic electroluminescent device:
the compound C01, the compound C05, the compound C08, the compound C13, the compound C15, the compound C16 and the compound C21 are selected as light-emitting layers to manufacture an organic electroluminescent device, and a commercialized phosphorescent host material mCP is selected as a comparative example.
It should be understood that the device implementation and results are merely for better explanation of the present invention and are not meant to be a limitation of the present invention.
Application example 1
Application of the compound C01 in an organic electroluminescent device:
a) cleaning of ITO (indium tin oxide) glass: respectively ultrasonically cleaning the ITO glass by using deionized water, acetone and ethanol for 30 minutes, and then treating the ITO glass in a plasma cleaner for 5 minutes;
b) sequentially vacuum evaporating a hole transport layer NPB (70nm) and a hole transport layer mCP (20nm) on the anode ITO glass at the evaporation rate of 0.1 nm/s;
c) vacuum evaporation of the light emitting layer, 4CzCNPy (10% wt): compound C01 (prepared in example 1), deposition Rate 0.1nm/s, Total film thickness by deposition 20nm
d) Vacuum evaporating BPhen as an electron transport layer on the luminescent layer, wherein the thickness of the BPhen is 30 nm; (ii) a
e) Vacuum evaporating an electron injection layer LiF on the electron transport layer, wherein the thickness of the electron injection layer LiF is 1 nm;
f) on the electron injection layer, cathode Al was vacuum-evaporated to a thickness of 100 nm.
The structure of the first device is ITO/NPB (70nm), mCP (20nm)/4CzCNPy (10% wt), compound C01(20nm)/BPhen (30nm)/LiF (1nm)/Al (100nm), compound C01 is used as the main material of the first device, and pressure is applied during vacuum evaporation<4.0×10-4Pa。
The light-emitting layers of application examples 2 to 7 were used to replace the compound C01 in application example 1 with the compound C05, the compound C08, the compound C13, the compound C15, the compound C16, and the compound C21, respectively, to obtain devices two to seven; light-emitting layer of comparative example a device eight was prepared by replacing compound C01 in application example 1 with mCP. The resulting device test results are shown in table 1.
TABLE 1
At 1000cd/m2Under the brightness, the device manufactured by the material has stable performance and higher current efficiency and power efficiency.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.