Organic compound containing cycloalkyl fluorene and dibenzofuran, and blue light-emitting composition and organic electroluminescent device comprising same

Abstract

The invention discloses an organic compound containing naphthenic fluorene and dibenzofuran, a blue light-emitting composition containing the organic compound and an organic electroluminescent device. The structural general formula of the organic compound is as shown in formula I in the specification. According to the organic compound, electron-rich substituent naphthenic fluorene and electron-deficient substituent dibenzofuran are introduced to specific positions on a boron-nitrogen molecular skeleton, so that electron and hole recombination energy of guest material molecules can be reduced, the transmission capability of carriers on the guest material molecules is improved, the guest material molecules are prevented from becoming traps in carrier transmission, and the transmission efficiency of the guest material molecules is improved. Therefore, the carrier transport process of the light-emitting layer is improved to a certain extent, the guest material is prevented from forming polaritons, the light-emitting efficiency of the light-emitting layer is improved, the host material with the anthracene parent nucleus as the characteristic is used in cooperation, stacking and molecular orientation between the host and the guest can be improved, the carrier transport process and the light-emitting process are improved, and the light-emitting efficiency of the light-emitting layer is improved. Therefore, the organic light-emitting device provided by the invention has more excellent efficiency performance on a top-emitting device. # imgabs0 #

Description

Technical Field

[0001] The invention belongs to the technical field of OLED, and specifically comprises an organic compound containing cycloalkylfluorene and dibenzofluorene, and a blue light-emitting composition and an organic electroluminescent device containing the same. Background Art

[0002] After more than 20 years of rapid development, organic light-emitting diodes (OLEDs) have gradually been recognized by people and have become a favorable competitor for the next generation of flat-panel display devices. OLEDs can provide highly saturated red, green, and blue colors. Full-color display devices made of OLEDs do not require additional backlight sources and have the advantages of brilliant colors, short response time, wide color gamut, and high contrast.

[0003] Among the current OLED luminescent materials, the luminescent properties of red and green materials can already meet the application requirements, while blue materials are limited by the low efficiency and lifespan that they can provide. Therefore, the development of new blue materials is a hot topic in current research. The current mainstream blue luminescent layer is composed of a host-guest doping system. The host material is usually anthracene-based host material, accounting for 97%-99%. The parent core structure of the guest material is also relatively fixed, generally a boron-nitrogen parent core structure. In the host-guest doping system, the guest material is usually doped into the host material at a ratio of 1%-3% and evenly distributed in the light-emitting layer. The excited state energy level and energy gap of the guest material are usually slightly smaller than those of the host material, which results in the generation of local traps in the light-emitting layer that can capture carriers due to the presence of the guest material. This causes the carriers to be injected into the light-emitting layer and then, when migrating in the light-emitting layer, they are captured by the guest material molecules after encountering the guest material and cannot continue to transfer, thereby reducing the transmission of carriers and even affecting the charge balance and reducing efficiency. In addition, after the guest material captures the carriers, when electrons or holes occupy the molecular frontier orbits, the guest material forms polarons due to the charge it carries, and the polaron-exciton quenching effect will seriously affect the process of the guest material obtaining the energy of the host radiation and emitting light. Therefore, it is urgent to develop a blue light doping material with a certain ability to transfer carriers. Summary of the invention

[0004] In view of the above problems existing in the prior art, the present invention provides an organic compound containing cycloalkylfluorene and dibenzofuran, and a blue light-emitting composition and an organic electroluminescent device containing the same.

[0005] To achieve the above objectives, the technical solutions adopted by the present invention include:

[0006] The first aspect of the present invention provides an organic compound containing cycloalkylfluorene and dibenzofuran, the general structural formula of the organic compound is shown in Formula I:

[0007]

[0008] In Formula I,

[0009] One of Ar1 and Ar2 represents a dibenzofuranyl group, and the other of Ar1 and Ar2 represents a carbon atom number of C1 to C 30 Substituted or unsubstituted alkyl, carbon number is C2~C 30 Substituted or unsubstituted alkenyl, carbon number is C3~C 30 Substituted or unsubstituted cycloalkyl, carbon number is C6~C 60 A substituted or unsubstituted aromatic group, with carbon atoms of C5~C 60 Substituted or unsubstituted heteroaryl, carbon number is C6~C 60 Substituted or unsubstituted condensed aromatic group, carbon number is C5~C 60 Any one of substituted or unsubstituted hetero-condensed ring aromatic groups;

[0010] R1 and R2 each independently represent hydrogen, deuterium, halogen, or a carbon number of C1 to C 30 Substituted or unsubstituted alkyl, carbon number is C2~C 30 Substituted or unsubstituted alkenyl, carbon number is C3~C 30 Substituted or unsubstituted cycloalkyl, carbon number is C6~C 60 A substituted or unsubstituted aromatic group, with carbon atoms of C5~C 60 Substituted or unsubstituted heteroaryl, carbon number is C6~C 60 Substituted or unsubstituted condensed aromatic group, carbon number is C5~C 60 Any one of substituted or unsubstituted hetero-condensed aromatic groups, and one of R1 and R2 represents a fluorenyl group containing a cycloalkyl group;

[0011] R3 and R4 each independently represent a substituted or unsubstituted aryl group, such as a substituted or unsubstituted phenyl group;

[0012] X represents O or S;

[0013] The substituents in R1, R2, R3, R4, Ar1 and Ar2 may be the same or different and are independently selected from deuterium, halogen, cyano, carbon atoms of C1 to C 10 Alkyl, carbon number is C6~C 60 The aromatic group has a carbon number of C5 to C 60 Heteroaryl, carbon number is C6~C 60 The condensed ring aromatic group has a carbon number of C3~C 30 One of a cycloalkyl group or an amino group, wherein two or more substituents may be connected to each other to form an aliphatic ring, an aromatic ring or a condensed ring;

[0014] The hydrogen on the compound represented by formula I can be replaced by deuterium, the nitrogen can be replaced by nitrogen-15, the sulfur can be replaced by sulfur-33, sulfur-34 or sulfur-36, the oxygen can be replaced by oxygen-17 or oxygen-18, the carbon can be replaced by carbon-13, and the boron can be replaced by boron-11.

[0015] Furthermore, the general structural formula of the organic compound is selected from one of the following structures:

[0016]

[0017] Furthermore, one of Ar1 and Ar2 represents a dibenzofuranyl group, and the other of Ar1 and Ar2 represents a carbon atom number of C1 to C 10 Substituted or unsubstituted alkyl, carbon number is C2~C 20 Substituted or unsubstituted alkenyl, carbon number is C3~C 20 Substituted or unsubstituted cycloalkyl, carbon number is C6~C 30 A substituted or unsubstituted aromatic group, with carbon atoms of C5~C 30 Substituted or unsubstituted heteroaryl, carbon number is C6~C 30 Substituted or unsubstituted condensed aromatic group, carbon number is C5~C 30 Any one of a substituted or unsubstituted hetero-condensed ring aromatic group.

[0018] Furthermore, R1 and R2 each independently represent hydrogen, deuterium, halogen, or a carbon number of C1 to C 10 Substituted or unsubstituted alkyl, carbon number is C2~C 20 Substituted or unsubstituted alkenyl, carbon number is C3~C 20 Substituted or unsubstituted cycloalkyl, carbon number is C6~C 30 A substituted or unsubstituted aromatic group, with carbon atoms of C5~C 30 Substituted or unsubstituted heteroaryl, carbon number is C6~C 30 Substituted or unsubstituted condensed aromatic group, carbon number is C5~C 30 any one of substituted or unsubstituted hetero-condensed ring aromatic groups, and one of R1 and R2 represents a fluorenyl group containing a cycloalkyl group.

[0019] Furthermore, the substituents in R1, R2, R3, R4, Ar1, and Ar2 may be the same or different and are independently selected from deuterium, halogen, cyano, a carbon atom number of C1 to C 10 Alkyl, carbon number is C6~C 30 The aromatic group has a carbon number of C5 to C 30 Heteroaryl, carbon number is C6~C30 The condensed ring aromatic group has a carbon number of C3~C 20 One of the cycloalkyl groups or amino groups, wherein two or more substituents can be connected to each other to form an aliphatic ring, an aromatic ring or a condensed ring.

[0020] Furthermore, the fluorenyl group containing a cycloalkyl group is selected from one of the structures shown below:

[0021]

[0022] Furthermore, the fluorenyl group containing a cycloalkyl group is selected from one of the structures shown below:

[0023]

[0024] Furthermore, the fluorenyl group containing a cycloalkyl group is selected from one of the structures shown below:

[0025]

[0026] Furthermore, one of R1 and R2 represents the above-mentioned fluorenyl group containing a cycloalkyl group, and the other represents one of a phenyl group, a C1-C4 alkyl-substituted phenyl group, a C3-C10 cycloalkyl-substituted phenyl group, and a cyclohexylmethyl-substituted phenyl group.

[0027] Furthermore, R3 and R4 each independently represent one of a phenyl group, a cyclohexylmethyl-substituted phenyl group, a C1-C4 alkyl-substituted phenyl group, and a deuterium-substituted phenyl group.

[0028] Furthermore, one of Ar1 and Ar2 represents a dibenzofuranyl group, and the other of Ar1 and Ar2 represents a phenyl group substituted with a C1-C4 alkyl group, a phenyl group substituted with a C3-C10 cycloalkyl group, or a phenyl group substituted with a cyclohexylmethyl group.

[0029] Furthermore, the organic compound is selected from one of the following structures:

[0030]

[0031]

[0032]

[0033]

[0034]

[0035]

[0036]

[0037]

[0038]

[0039]

[0040]

[0041] The second aspect of the present invention provides a blue light-emitting composition, which comprises the organic compound as described above, and a compound having a general structural formula as shown in Formula II:

[0042]

[0043] In Formula II,

[0044] Ar3 represents the number of carbon atoms C6~C 60 a substituted or unsubstituted aryl group;

[0045] Ar4 represents one of the structures shown in Formula III-1 to Formula III-5:

[0046]

[0047] In the compound represented by formula II, at least one hydrogen atom is replaced by deuterium.

[0048] Furthermore, Ar3 represents a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group.

[0049] Further, Ar4 represents one of the structures shown below:

[0050]

[0051]

[0052] Furthermore, the compound of formula II is selected from one of the structures shown below:

[0053]

[0054]

[0055]

[0056]

[0057] The third aspect of the present invention provides an organic electroluminescent device, which includes an anode, a hole transport region, a light-emitting layer, an electron transport region, and a cathode arranged in sequence on a substrate; wherein the light-emitting layer includes one or more organic compounds as described above or includes one or more blue light-emitting compositions as described above.

[0058] Furthermore, the light-emitting layer includes a host material and a guest material, wherein the guest material includes one or more compounds having a general structural formula as shown in Formula I.

[0059] Furthermore, the host material includes one or more compounds having a general structural formula as shown in Formula II.

[0060] Beneficial effects of the present invention:

[0061] The invention provides an organic compound containing cycloalkylfluorene and dibenzofuran. From a structural point of view, the organic compound introduces an electron-rich substituent cycloalkylfluorene (at the R1 or R2 position) and an electron-deficient substituent dibenzofuran (at the Ar1 or Ar2 position) at specific positions on a boron nitrogen molecular skeleton, wherein the cycloalkylfluorene is introduced into the boron nitrogen parent nucleus as an aromatic group on a diarylamine through an aromatic amine substituent, and the dibenzofuran is directly introduced into the boron nitrogen parent nucleus as a substituent, which can reduce the electron and hole reorganization energy of a guest material molecule, improve the carrier transmission ability on the guest material molecule, and avoid the guest material molecule becoming a trap in the carrier transmission, thereby improving the carrier transmission process of a light-emitting layer to a certain extent, avoiding the formation of polarons in the guest material, and improving the luminous efficiency of the light-emitting layer; in addition, since the diarylamine has a large steric hindrance, the boron nitrogen material of the invention can reduce the alkyl substituent around the parent nucleus, and appropriately introduce a plurality of phenyl groups to adjust the molecular orientation and improve the molar absorption coefficient.

[0062] The present invention also provides a blue light-emitting composition, which uses the above-mentioned organic compound containing cycloalkylfluorene and dibenzofuran as a guest material and a compound characterized by an anthracene mother core (compound shown in Formula II) as a host material for the preparation of a light-emitting layer of an organic electroluminescent device. Since both the host and guest materials contain large polar fragments of dibenzofuran / naphthylbenzofuran structure, the two can produce good interaction, and the advantage of the large absorption coefficient of the BD material of the present invention can be further expanded. The dibenzofuran fragment on the guest material and the dibenzofuran / naphthylbenzofuran fragment on the host material are connected to the boron nitrogen mother core and the anthracene core in the form of a single bond substituent, so that the fragment has a certain free rotation ability. Through the interaction between the oxygen atoms with large electronegativity shared by the host and the guest, the stacking and molecular orientation between the host and the guest are improved, and then the carrier transport process and the light extraction process are improved, so that the organic electroluminescent device of the present invention has a more excellent efficiency performance on the top emission device. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 It is a schematic structural diagram of the organic electroluminescent device of the present invention.

[0064] Description of the drawings: 1-substrate, 2-anode, 3-hole injection layer, 4-hole transport layer, 5-luminescence auxiliary layer, 6-luminescent layer, 7-hole blocking layer, 8-electron transport layer, 9-electron injection layer, 10-cathode. DETAILED DESCRIPTION

[0065] In order to more clearly understand the content of the present invention, it will be described in detail with reference to the drawings and embodiments.

[0066] The compounds of the present invention are suitable for use in light-emitting elements, display panels and electronic devices, and are particularly suitable for use in organic electroluminescent devices. The electronic device described in the present invention is a device comprising a layer of at least one organic compound, and the device may also comprise an inorganic material or a layer formed entirely of an inorganic material. The electronic device is preferably an organic electroluminescent device (OLED), an organic integrated circuit (O-IC), an organic field effect transistor (O-FET), an organic thin film transistor (O-TFT), an organic light-emitting transistor (O-LET), an organic solar cell (O-SC), an organic dye-sensitized solar cell (O-DSSC), an organic optical detector, an organic photoreceptor, an organic field quenching device (O-FQD), a light-emitting electrochemical cell (LEC), an organic laser diode (O-laser) and an organic plasma emission device. The electronic device is preferably an organic electroluminescent device (OLED). The structural schematic diagram of an exemplary organic electroluminescent device is shown in FIG. Figure 1 shown.

[0067] Experimental Section

[0068] In order to understand the content of the present invention more clearly, the polycyclic compound, the preparation method of the compound and the luminescent characteristics of the device will be explained in detail in conjunction with the examples. Various chemical reactions can be applied to the synthetic method of the compound of an embodiment of the present invention. However, it should be noted that the synthetic method of the compound of an embodiment of the present invention is not limited to the synthetic method described below. Unless otherwise indicated, the subsequent synthesis is carried out in anhydrous solvent under a protective gas atmosphere. Solvents and reagents can be purchased from conventional reagent suppliers.

[0069] Synthesis Example 1

[0070]

[0071] A01 (11.65 g; 10 mmol) was added to tert-butylbenzene (125 ml), then the temperature was lowered to -50°C under nitrogen protection, 12.4 ml (21 mmol) of 1.7 M tert-butyl lithium pentane solution was added, the temperature was raised to 60°C and stirred for 2 hours, then the temperature was lowered to 0°C, 2.0 ml (21 mmol) of boron tribromide was added and stirred for 0.5 h, the temperature was lowered to 0°C, 3.65 ml (21 mmol) of N, N-diisopropylethylamine was added, the temperature was raised to 60°C and stirred for 2 h, the temperature was lowered to room temperature, ice water was added to quench and separate the liquids, the organic phase was filtered and dehydrated with anhydrous magnesium sulfate, the organic solvent was removed by rotation, and the crude product was purified by recrystallization from dichloromethane and n-heptane. Finally, the product B01: 0.91 g, yield: 8%, MS (m / z) (M+): 1139 was obtained.

[0072] Synthesis Example 2

[0073]

[0074] The method is the same as that of Synthesis Example 1, except that A02 (12.63 g; 10 mmol) is used to replace A01, and finally the product B02 is obtained: 0.74 g, yield: 6%, MS (m / z) (M+): 1237.

[0075] Synthesis Example 3

[0076]

[0077] The method is the same as that of Synthesis Example 1, except that A03 (12.61 g; 10 mmol) is used to replace A01, and finally product B03 is obtained: 0.99 g, yield: 8%, MS (m / z) (M+): 1235.

[0078] Synthesis Example 4

[0079]

[0080] The method is the same as that of Synthesis Example 1, except that A04 (12.49 g; 10 mmol) is used to replace A01, and finally product B04 is obtained: 0.73 g, yield: 6%, MS (m / z) (M+): 1223.

[0081] Synthesis Example 5

[0082]

[0083] The method is the same as that of Synthesis Example 1, except that A05 (12.19 g; 10 mmol) is used to replace A01, and finally product B05: 0.6 g, yield: 5%, MS (m / z) (M+): 1193.

[0084] Synthesis Example 6

[0085]

[0086] The method is the same as that of Synthesis Example 1, except that A06 (12.07 g; 10 mmol) is used to replace A01, and finally product B06 is obtained: 0.71 g, yield: 6%, MS (m / z) (M+): 1181.

[0087] Synthesis Example 7

[0088]

[0089] The method is the same as that of Synthesis Example 1, except that A07 (12.35 g; 10 mmol) is used to replace A01, and finally the product B07 is obtained: 1.09 g, yield: 9%, MS (m / z) (M+): 1209.

[0090] Synthesis Example 8

[0091]

[0092] The method is the same as that of Synthesis Example 1, except that A08 (11.72 g; 10 mmol) is used to replace A01, and finally the product B08 is obtained: 0.69 g, yield: 6%, MS (m / z) (M+): 1146.

[0093] Synthesis Example 9

[0094]

[0095] The method is the same as that of Synthesis Example 1, except that A09 (12.47 g; 10 mmol) is used to replace A01, and finally the product B09 is obtained: 1.1 g, yield: 9%, MS (m / z) (M+): 1221.

[0096] Synthesis Example 10

[0097]

[0098] The method is the same as that of Synthesis Example 1, except that A10 (12.82 g; 10 mmol) is used to replace A01, and finally product B10 is obtained: 0.88 g, yield: 7%, MS (m / z) (M+): 1256.

[0099] Synthesis Example 11

[0100]

[0101] The method is the same as that of Synthesis Example 1, except that A11 (12.31 g; 10 mmol) is used to replace A01, and finally product B11 is obtained: 0.84 g, yield: 7%, MS (m / z) (M+): 1205.

[0102] Synthesis Example 12

[0103]

[0104] The method is the same as that of Synthesis Example 1, except that A12 (13.05 g; 10 mmol) replaces A01, and finally the product B12 is obtained: 0.89 g, yield: 7%, MS (m / z) (M+): 1279.

[0105] Synthesis Example 13

[0106]

[0107] The method is the same as that of Synthesis Example 1, except that A13 (13.45 g; 10 mmol) is used to replace A01, and finally product B13 is obtained: 0.79 g, yield: 6%, MS (m / z) (M+): 1319.

[0108] Synthesis Example 14

[0109]

[0110] The method is the same as that of Synthesis Example 1, except that A14 (12.47 g; 10 mmol) replaces A01, and finally the product B14 is obtained: 0.85 g, yield: 7%, MS (m / z) (M+): 1221.

[0111] Synthesis Example 15

[0112]

[0113] The method is the same as that of Synthesis Example 1, except that A15 (12.91 g; 10 mmol) is used to replace A01, and finally product B15 is obtained: 0.89 g, yield: 7%, MS (m / z) (M+): 1265.

[0114] Synthesis Example 16

[0115]

[0116] The method is the same as that of Synthesis Example 1, except that A16 (12.75 g; 10 mmol) is used to replace A01, and finally product B16 is obtained: 0.87 g, yield: 7%, MS (m / z) (M+): 1249.

[0117] Synthesis Example 17

[0118]

[0119] The method is the same as that of Synthesis Example 1, except that A17 (12.19 g; 10 mmol) is used to replace A01, and finally the product B17 is obtained: 1.07 g, yield: 9%, MS (m / z) (M+): 1193.

[0120] Synthesis Example 18

[0121]

[0122] The method is the same as that of Synthesis Example 1, except that A18 (11.56 g; 10 mmol) is used to replace A01, and finally the product B18 is obtained: 1.02 g, yield: 9%, MS (m / z) (M+): 1130.

[0123] Synthesis Example 19

[0124]

[0125] The method is the same as that of Synthesis Example 1, except that A19 (12.19 g; 10 mmol) is used to replace A01, and finally the product B19 is obtained: 0.84 g, yield: 7%, MS (m / z) (M+): 1193.

[0126] Synthesis Example 20

[0127]

[0128] The method is the same as that of Synthesis Example 1, except that A20 (13.03 g; 10 mmol) replaces A01, and finally the product B20 is obtained: 1.02 g, yield: 8%, MS (m / z) (M+): 1277.

[0129] Synthesis Example 21

[0130]

[0131] The method is the same as that of Synthesis Example 1, except that A21 (12.45 g; 10 mmol) replaces A01, and finally the product B21 is obtained: 0.85 g, yield: 7%, MS (m / z) (M+): 1219.

[0132] Synthesis Example 22

[0133]

[0134] The method is the same as that of Synthesis Example 1, except that A22 (13.17 g; 10 mmol) replaces A01, and finally the product B22 is obtained: 0.90 g, yield: 7%, MS (m / z) (M+): 1291.

[0135] Synthesis Example 23

[0136]

[0137] The method is the same as that of Synthesis Example 1, except that A23 (12.05 g; 10 mmol) replaces A01, and finally the product B23 is obtained: 0.59 g, yield: 5%, MS (m / z) (M+): 1179.

[0138] Synthesis Example 24

[0139]

[0140] The method is the same as that of Synthesis Example 1, except that A24 (12.5 g; 10 mmol) is used to replace A01, and finally the product B24 is obtained: 0.98 g, yield: 8%, MS (m / z) (M+): 1224.

[0141] Synthesis Example 25

[0142]

[0143] The method is the same as that of Synthesis Example 1, except that A25 (12.73 g; 10 mmol) is used to replace A01, and finally the product B25 is obtained: 0.75 g, yield: 6%, MS (m / z) (M+): 1247.

[0144] Comparative Example Compound

[0145]

[0146] Compound properties

[0147] In order to further illustrate the reasons why the technical effects of the example compounds of the present invention and the comparative example compounds may differ, the hole reorganization energy, electron reorganization energy, molecular orientation, and molar absorption coefficient of the guest molecule were calculated and tested.

[0148] Calculation / testing method:

[0149] 1. Through ORCA software, based on the density functional theory (DFT) calculation method (basis set level is set to: b3lyp / 6-31g(d), charge number 0), the molecular structure is geometrically optimized (Optimization), and on this basis, the reorganization energy (eV) of the compound under positive and negative charges is further calculated. Generally, the smaller the reorganization energy, the faster the mobility, which means that the probability of carriers being trapped by guest molecules is lower, and the carrier utilization rate is higher, which is conducive to improving efficiency.

[0150] 2. The transition dipole moment orientation of the molecules in the light-emitting layer was measured by angle-dependent fluorescence spectroscopy using a molecular orientation test system produced by Hamamatsu (HAMAMATSU) of Japan. The operation is as follows:

[0151] The compositions are co-evaporated to form an organic film, wherein the guest material is selected from the materials shown in Table 1, the doping mass concentration ratio is 3%, and the host material is selected from BH34, mass concentration ratio 97%, evaluates the performance differences of different compositions in orientation.

[0152] Test method: Use 365nm ultraviolet light for excitation, measure the distribution of the fluorescence intensity of the organic film with the test angle, and determine its anisotropy factor Θ (dimensionless) through optical fitting software.

[0153]

[0154] In formula (1), p z represents the vertical dipole electrode moment, p represents the dipole electrode moment, represents the emission power of the total vertical dipole, ∑p2 represents the total emission power of all dipoles, the completely horizontally aligned transition dipole moment vector leads to Θ=0, the isotropic distribution is Θ=0.33, the vertically oriented dipole is Θ=1, the smaller Θ is, the more horizontal luminescent components there are in the organic film doping material, and the higher the utilization rate of the guest material's radiant luminescence.

[0155] 3. Maximum absorption wavelength and maximum molar absorption coefficient test: The guest materials shown in Table 1 were mixed with toluene to a concentration of 1×10 -2 mol / L toluene solution, the UV absorption spectrum of the solution in the range of 290-600nm was tested by PerkinELmer's LAMBDA35 UV-visible spectrophotometer, and the wavelength at the rightmost absorption peak is the maximum absorption wavelength λ max , corresponding to the maximum molar absorption coefficient ε max (L / (mol·cm)) was calculated by formula (2);

[0156] ε max =A / (b×c)————Formula (2);

[0157] In formula (2), A is the absorbance at the maximum absorption peak; b is the optical path length, mm; and c is the concentration of the guest material, mol / L.

[0158] Table 1

[0159]

[0160]

[0161] It can be seen from the above table that the materials of the present invention have smaller hole and electron reorganization energies than the comparative materials. Although DBBD01 has a very small electron reorganization energy, this is because it introduces multiple dibenzofurans and the electron cloud density is not dispersed by directly replacing the aromatic group on the lower side of the parent nucleus, which makes it less likely to capture electrons, but the hole reorganization energy is significantly increased, which greatly increases the probability of capturing holes to form polarons, and the possibility of capturing holes is high. Generally, the hole transmission of organic semiconductors is faster than that of electrons, so that the hole concentration in the light-emitting recombination zone is slightly higher than that of electrons. In other words, this material is more likely to form hole traps, which has a greater negative impact on the overall carrier transport. Compared with the other two comparative examples DBBD02 and DBBD03, which do not introduce cycloalkylfluorenyl fragments, the present invention simultaneously introduces cycloalkylfluorenyl fragments and dibenzofuran, so that the hole reorganization energy and electron reorganization energy of the material of the present invention are relatively smaller, which means that the material of the present invention is more difficult to capture and limit carriers, and is more conducive to the transport and recombination of carriers in the light-emitting layer; in addition, compared with the comparative example, the material of the present invention has a smaller anisotropy factor and a larger molar absorption coefficient. This may be because the present invention introduces aromatic substituents into the lower phenyl and thienyl parts of the parent core skeleton. On the one hand, the size of the parent core boron nitrogen plane is expanded, which is beneficial to the horizontal orientation of the material during evaporation, reducing the anisotropy factor, which is beneficial to the light extraction process of the organic device and improving the device efficiency. On the other hand, the introduction of aromatic groups can also improve the molar absorption coefficient to a certain extent, which is beneficial to improve the energy transfer process between the host and the guest, thereby improving the device efficiency. DBBD02 does not introduce phenyl substituents on the thiophene part, which limits its performance in terms of absorption coefficient. The absorption coefficient of DBBD03 is relatively good, but its side groups all have large steric hindrance groups, which results in poor molecular orientation performance.

[0162] Fabrication and characterization of OLEDs

[0163] Device Embodiment

[0164] The organic electroluminescent device provided by the present invention comprises an anode, a hole transport region, a light-emitting layer, an electron transport region, and a cathode which are sequentially arranged on a substrate;

[0165] Furthermore, the hole transport region includes a hole injection layer, a hole transport layer and a light-emitting auxiliary layer; and the electron transport region includes an electron transport layer and an electron injection layer.

[0166] Furthermore, the light-emitting layer is composed of a host material and a guest material, and the host material of the light-emitting layer can be composed of one molecular material or multiple molecular materials.

[0167] The composition of the present invention can be used for the light-emitting layer of the above-mentioned organic electroluminescent device.

[0168] The anode in the embodiment adopts anode materials commonly used in the art, such as ITO, Ag or their multilayer structures. The hole injection layer adopts hole injection materials commonly used in the art, and F4TCNQ, HATCN, NDP-9, etc. are added for doping. The hole transport layer adopts hole transport materials commonly used in the art. The light-emitting layer adopts the host and guest material composition provided by the present invention. The electron transport layer adopts electron transport materials commonly used in the art. The electron injection layer adopts electron injection materials commonly used in the art, such as Liq, LiF, Yb, etc. The cathode adopts materials commonly used in the art, such as metal Al, Ag or metal mixtures (Ag-doped Mg, Ag-doped Ca, etc.).

[0169] The electrode preparation method and the deposition method of each functional layer in this embodiment are conventional methods in the art, such as vacuum thermal evaporation or inkjet printing, etc., which will not be described in detail here. Only some process details and test methods in the preparation process are supplemented as follows:

[0170] Device Example 1

[0171] The substrates used in the present invention were subjected to the following operations: the ITO substrate was patterned so that its luminous area had a size of 3 mm×3 mm, and then water / isopropanol ultrasound, UV / ozone irradiation, and then dried at 100°C. After that, the ITO substrate was mounted on a substrate holder of a vacuum deposition device and the pressure was adjusted so that the vacuum rate became 1×10 -7torr. Then the following operations were performed: first, on the ITO layer (anode) formed on the substrate, the compound HT01 and the compound PD01 (the mass ratio of HT01 to PD01 was 97:3) were vacuum deposited with a thickness of 10 nm to form a hole injection layer; secondly, on the hole injection layer, the compound HT01 was vacuum deposited with a thickness of 120 nm to form a hole transport layer; secondly, on the hole transport layer, the compound BP01 was vacuum deposited with a thickness of 5 nm to form an electron blocking layer; secondly, on the electron blocking layer, a mixture of the compound BH01 and the compound BD01 provided by the present invention was vacuum deposited with a thickness of 20 nm to form a light-emitting layer, wherein BH01 was used as a host material and B01 was used as a guest material, and the mass ratio of the host to the guest material was 98:2; then, on the light-emitting layer, the compound HB01 was vacuum deposited with a thickness of 5 nm to form a hole blocking layer; then Then, on the hole blocking layer, compound ET01 and compound Liq (the mass ratio of ET01 to Liq is 1:1) are vacuum deposited with a thickness of 20 nm to form an electron transport layer; then, on the electron transport layer, Yb is vacuum deposited with a thickness of 1 nm to form an electron injection layer, and then on the electron injection layer, Mg and Ag (the mass ratio of Mg and Ag is 1:9) are deposited with a thickness of 15 nm to form a cathode, and then on the cathode, compound CP01 is deposited with a thickness of 50 nm to form a covering layer. Finally, the vapor-deposited substrate is packaged, and the cleaned cover plate is coated with UV glue using a glue coating equipment, and then the coated cover plate is moved to the pressing section, and the vapor-deposited substrate is placed on the upper end of the cover plate. Finally, the substrate and the cover plate are bonded under the action of a bonding device, and the UV glue is light-cured to prepare a laminated organic electroluminescent device.

[0172] Except for the guest material of the light-emitting layer, the molecular structures of the materials in the remaining layers are as follows:

[0173]

[0174] Device Examples 2-25

[0175] The above method was used to prepare organic electroluminescent devices from other embodiments in Table 2, and the guest materials shown in the embodiments in Table 2 were used to replace BD01 in device embodiment 1, and the host materials were used to replace BH01 in device embodiment 1 to prepare blue light organic electroluminescent device embodiments 2-25.

[0176] The compound structures of the host materials described in Table 2 are provided below:

[0177]

[0178]

[0179] Device Comparison Examples 1-4

[0180] The comparative examples in Table 2 were made into organic electroluminescent devices by adopting the above method, and the guest materials shown in the comparative examples in Table 2 were used to replace BD01 in device example 1, and the host materials were used to replace BH01 in device example 1 to prepare blue light organic electroluminescent device comparative examples 1-4.

[0181] The OLED devices described above were tested by standard methods. For this purpose, at J = 10 mA / cm 2 The driving voltage and luminous efficiency of the organic electroluminescent device are determined at a current density of J = 10 mA / cm 2 When working under LT95, the luminous brightness drops to 95% of its initial value L0 after time LT95.

[0182] The test instruments and methods for testing the performance of the OLED devices in the above embodiments and comparative examples are as follows:

[0183] The luminous efficiency CE (cd / A) and color coordinates (CIEy) were tested using a spectrum scanner PhotoResearch PR-635;

[0184] Current density and lighting voltage: tested using a digital source meter Keithley 2400;

[0185] The luminous efficiency of blue light devices is greatly affected by chromaticity. The industry generally uses BI value as the basis for the efficiency of blue light devices. BI (Blue index) is obtained by dividing the luminous efficiency CE (cd / A) by the color coordinate (CIEy);

[0186] Life test: Use silicon photoelectric OLED device life test system.

[0187] The performance test results of the above devices are listed in Table 2.

[0188] Table 2 Blue light device performance test results

[0189]

[0190]

[0191] It can be seen from the above results that compared with the comparative example, under a similar mother core skeleton, the present invention can significantly improve the BI efficiency of the top emission device. This is the effect of introducing phenyl substituents on the thienyl group and the lower phenyl group of the mother core, as well as introducing two fluorene structures. In particular, by using the main material defined by the present invention, since both the host and the guest contain large polar fragments of dibenzofuran / naphthylbenzofuran structure, the two can produce good interaction, and the advantage of the large absorption coefficient of the BD material of the present invention can be further expanded. The dibenzofuran fragment on the guest and the dibenzofuran / naphthylbenzofuran fragment on the host are connected to the boron nitrogen mother core and the anthracene core in the form of a single bond substituent, so that the fragment has a certain free rotation ability, and the stacking and molecular orientation between the host and the guest are improved through the interaction between the oxygen atoms with large electronegativity shared by the host and the guest. , thereby improving the carrier transport process and the light extraction process, so that compared with the device formed by the host without furan structure in the comparative example, the device of the present invention has a more excellent efficiency performance in the top emission device. Compared with the device comparative example 3, although the host material of the present invention is used to improve the lifespan to a certain extent, both the host and the guest contain dibenzofuran structure, but it may be because DBBD03 lacks cycloalkylfluorene structure and is easy to capture holes to form polarons, so the BI efficiency of the comparative example is not good. Compared with the device comparative example 4, both the host and the guest contain dibenzofuran, but the host is not deuterated, and the lifespan of the comparative example is not good. The deuterated host used in the device of the present invention significantly improves the lifespan performance of the device and has a good interaction with the guest. By combining with the BD material of the present invention to construct a device, an electroluminescent organic light-emitting device with both high efficiency and lifespan performance is provided.

[0192] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the protection scope of the present invention.

Claims

1. An organic compound containing cycloalkylfluorene and dibenzofuran, characterized in that: The general structural formula of the organic compound is shown in Formula I: In Formula I, One of Ar1 and Ar2 represents a dibenzofuranyl group, and the other of Ar1 and Ar2 represents a carbon atom number of C1 to C 30 Substituted or unsubstituted alkyl, carbon number is C2~C 30 Substituted or unsubstituted alkenyl, carbon number is C3~C 30 Substituted or unsubstituted cycloalkyl, carbon number is C6~C 60 A substituted or unsubstituted aromatic group, with carbon atoms of C5~C 60 Substituted or unsubstituted heteroaryl, carbon number is C6~C 60 Substituted or unsubstituted condensed aromatic group, carbon number is C5~C 60 Any one of substituted or unsubstituted hetero-condensed ring aromatic groups; R1 and R2 each independently represent hydrogen, deuterium, halogen, or a carbon number of C1 to C 30 Substituted or unsubstituted alkyl, carbon number is C2~C 30 Substituted or unsubstituted alkenyl, carbon number is C3~C 30 Substituted or unsubstituted cycloalkyl, carbon number is C6~C 60 A substituted or unsubstituted aromatic group, with carbon atoms of C5~C 60 Substituted or unsubstituted heteroaryl, carbon number is C6~C 60 Substituted or unsubstituted condensed aromatic group, carbon number is C5~C 60 any one of substituted or unsubstituted hetero-condensed aryl groups, and one of R1 and R2 represents a fluorenyl group containing a cycloalkyl group; R3 and R4 each independently represent a substituted or unsubstituted aryl group; X represents O or S; The substituents in R1, R2, R3, R4, Ar1 and Ar2 may be the same or different and are independently selected from deuterium, halogen, cyano, carbon atoms of C1 to C 10 Alkyl, carbon number is C6~C 60 The aromatic group has a carbon number of C5 to C 60 Heteroaryl, carbon number is C6~C 60 The condensed ring aromatic group has a carbon number of C3~C 30 One of a cycloalkyl group or an amino group, wherein two or more substituents may be connected to each other to form an aliphatic ring, an aromatic ring or a condensed ring; The hydrogen on the compound represented by formula I can be replaced by deuterium, the nitrogen can be replaced by nitrogen-15, the sulfur can be replaced by sulfur-33, sulfur-34 or sulfur-36, the oxygen can be replaced by oxygen-17 or oxygen-18, the carbon can be replaced by carbon-13, and the boron can be replaced by boron-11.

2. The organic compound according to claim 1, characterized in that The general structural formula of the organic compound is selected from one of the following structures:

3. The organic compound according to claim 1, characterized in that The fluorenyl group containing a cycloalkyl group is selected from one of the structures shown below:

4. The organic compound according to claim 1, characterized in that The fluorenyl group containing a cycloalkyl group is selected from one of the structures shown below:

5. The organic compound according to claim 1, characterized in that The organic compound is selected from one of the following structures:

6. A blue light-emitting composition, characterized in that: The organic compound comprises the organic compound as described in any one of claims 1 to 5, and the compound with the general structural formula as shown in Formula II: In Formula II, Ar3 represents the number of carbon atoms C6~C 60 a substituted or unsubstituted aryl group; Ar4 represents one of the structures shown in Formula III-1 to Formula III-5: In the compound represented by formula II, at least one hydrogen atom is replaced by deuterium.

7. The blue light-emitting composition according to claim 6, characterized in that: Ar3 represents a substituted or unsubstituted phenyl group or a substituted or unsubstituted naphthyl group.

8. The blue light-emitting composition according to claim 6, characterized in that: The Ar4 represents one of the structures shown below:

9. The blue light-emitting composition according to claim 6, characterized in that: The compound of formula II is selected from one of the structures shown below:

10. An organic electroluminescent device, characterized in that: It includes an anode, a hole transport region, a light-emitting layer, an electron transport region, and a cathode arranged in sequence on a substrate; wherein the light-emitting layer includes one or more organic compounds as described in any one of claims 1 to 5 or includes one or more blue light-emitting compositions as described in any one of claims 6 to 9.

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