Chiral liquid crystal fluorescent materials and their applications

Abstract

The present invention belongs to the technical field of organic electroluminescent materials, and specifically relates to a high-efficiency chiral liquid crystal fluorescent material and its application. The chiral liquid crystal fluorescent material is prepared by using binaphthol as the chiral center, biphenyl derivatives as the liquid crystal primitive, diphenyl sulfone or cyano as the electron acceptor, and aromatic amine derivatives as the electron donor. This type of luminescent material can transition from the triplet state to the singlet state through reverse intersystem crossing to obtain 100% exciton utilization. At the same time, this type of material exhibits obvious liquid crystal properties. Using this type of chiral liquid crystal fluorescent material as the dopant of the luminescent layer, an electroluminescent device is prepared by a solution method, and its maximum external quantum efficiency reaches more than 10%. The present invention discusses in detail the relationship between molecular structure and performance, which is of great significance for constructing a new type of chiral liquid crystal fluorescent material.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic electroluminescent materials, and relates to a class of chiral liquid crystal fluorescent materials, mainly to a class of chiral liquid crystal fluorescent materials with binaphthol as a chiral center, biphenyl-based mesogen units as flexible alkyl chains, diphenyl sulfone or cyano as electron acceptors, and aromatic amine derivatives as electron donors, and their applications in organic electroluminescent devices. Background Art

[0002] The development of OLED luminescent materials has gone through the development of the first generation of traditional fluorescence, the second generation of phosphorescence, and the third generation of thermally activated delayed fluorescence and thermal exciton luminescent materials. Due to the limitation of spin statistics, the exciton utilization rate of traditional fluorescent materials is only 25%. Phosphorescent materials based on precious metal complexes can also emit light through radiation transitions due to the spin-orbit coupling effect, and the exciton utilization rate can reach 100%. However, phosphorescent materials still face problems such as high material cost and short life of blue light devices.

[0003] In this context, the Adachi group proposed TADF materials with reverse intersystem crossing between the lowest singlet (S1) and triplet (T1) excited states, while Professor Ma Yuguang et al. proposed hot exciton materials with high-energy triplet anti-intersystem crossing characteristics. Both can achieve 100% exciton utilization and have received widespread attention. However, it is difficult for hot exciton materials to be applied to daily display fields simply by improving exciton utilization. Because most current display devices require the use of anti-glare filters, including linear polarizers (LP) and quarter-wave plates (QWP) to limit the reflection of external light. The use of this type of filter also means the loss of up to 50% of the electroluminescence generated by the OLED. Therefore, these challenges have prompted the study of a new generation of devices, in which CP-OLEDs can directly emit circularly polarized light, thereby reducing or even eliminating these filters, which can improve image brightness at lower power consumption. And circularly polarized light also has its unique optical properties, such as optical data storage, 3D display, and bio-imaging. In addition, research by Beijing Tongren Hospital and other institutions has shown that watching circularly polarized light displays can effectively alleviate vision loss compared to traditional non-polarized light displays. This is because circularly polarized light is closer to natural light and can effectively reduce people's visual fatigue. In CP-OLEDs, chiral fluorescence, phosphorescence, TADF, and thermoexciton materials have all made great progress, but due to the shortcomings of 25% internal quantum yield of fluorescence and high pollution and high cost of phosphorescence, the research on chiral TADF and thermoexciton materials has attracted the most attention. In theory, there are two main strategies for the construction of chiral TADF and thermoexciton molecules. One is based on the inherent chiral TADF and thermoexciton chromophores (axial, planar or point chirality), and the other is to utilize the chiral perturbation of TADF or thermoexciton units. Although the former method usually gives a higher luminescence asymmetry factor (glum ) value, but it requires the resolution of the enantiomers by different methods (chiral HPLC or resolution by diastereoisomeric separation). In contrast, the latter strategy is based on synthesis, starting from commercially available enantiomeric products, which greatly facilitates their large-scale synthesis and application as emitting materials in OLEDs. However, the chiral TADF designed in this way, as well as the g of the hot excitons lum Usually small (usually 10 -3 ), so it is difficult to commercialize. Summary of the invention

[0004] In order to further balance the g value and efficiency and obtain an efficient high-g value CP-OLED, the present invention uses binaphthol as a chiral source, aromatic amine derivatives as donors, diphenyl sulfone or cyano as an acceptor, and biphenyl-based mesogen units as peripheral flexible alkyl chains to construct chiral liquid crystal TADF and chiral liquid crystal thermoexciton luminescent materials. Liquid crystal is introduced into chiral TADF and chiral thermoexciton materials, carbazole is a donor, and cyano is an acceptor. The combination of the two is conducive to the separation of the highest occupied molecular orbital (HOMO) and the lowest occupied molecular orbital (LUMO), further reducing the single-triplet energy range (ΔE ST ), which is conducive to the formation of TADF molecules. The potential energy of dimethylacridine is close to the local excited (LE) state, and its strong electron donating ability will form a charge transfer (CT) transition between the donor and the diphenyl sulfone acceptor, thereby forming a thermoexciton channel. The binaphthol unit is a relatively stable axial chirality source. And due to the vibration of too many flexible chains, it is conducive to suppressing the non-radiative transition of molecules and obtaining high-efficiency chiral liquid crystal thermoexciton materials. At the same time, the present invention also systematically studies the influence of different positions of donors and acceptors and the number of biphenyl-based mesogenic units on the photophysical properties of the material, which is of great significance for exploring efficient chiral liquid crystal thermoexciton materials.

[0005] In order to achieve the above technical purpose, the material synthesized by the present invention has the following structure:

[0006]

[0007] The synthetic material is preferably

[0008]

[0009] Another object of the present invention is to provide an application of a chiral liquid crystal fluorescent material as a dopant for an organic light emitting diode light emitting layer, thereby obtaining an organic light emitting diode with a maximum external quantum efficiency of >10%.

[0010] The structure of the organic light-emitting diode is: ITO / PEDOT:PSS / mCP:30wt%CzAcSF(R) / (S)-1 / TSPO1 / TmPyPB / LiF / Al.

[0011] The thickness of the light-emitting layer is 30 nm; the doping amount of the fluorescent material as a dopant is 0.5-1.5 wt%.

[0012] The technical advantages of this patent are:

[0013] 1. Introduce chiral units and liquid crystal primitives into fluorescent materials to construct a series of new chiral liquid crystal fluorescent materials; give them chirality and liquid crystal properties while maintaining the photophysical properties of the light-emitting units;

[0014] 2. The introduction of fluorine atoms into the liquid crystal unit is beneficial to suppress the non-radiative transition of molecules and improve the luminescence efficiency of chiral liquid crystal fluorescent materials;

[0015] 3. Using this new type of chiral liquid crystal fluorescent material as a dopant for the light-emitting layer, a highly efficient solution-processed electroluminescent device can be obtained, with a maximum external quantum efficiency exceeding 10%. BRIEF DESCRIPTION OF THE DRAWINGS

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Figure 1

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Figure 2

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Figure 3

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Figure 5

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Figure 6

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Figure 7

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Figure 8

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Fig.12

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Fig.15

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Fig.16

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Fig.17

[0033] The following specific implementation cases are intended to further illustrate the present invention, but these specific implementation cases do not limit the protection scope of the present invention in any way.

[0034] Example 1

[0035] The synthesis scheme of the chiral liquid crystal fluorescent material of the present invention is as follows:

[0036]

[0037] Synthesis of compound 1

[0038] 2,3-difluoro-4-ethoxyphenylboronic acid (10g, 50mmol), 1-iodo-4-(4-pentylcyclohexyl)benzene (18g, 50mmol), tetrakistriphenylphosphine palladium (500mg, 0.50mmol), 2M potassium carbonate aqueous solution (30mL) and 150mL tetrahydrofuran were added to a 500mL single-necked flask and heated to reflux for 24h. After the reaction was completed, it was cooled to room temperature, extracted with dichloromethane (3×50mL) after adding water, washed three times with water, dried over anhydrous magnesium sulfate, filtered and collected the filtrate, and the organic solvent was removed by rotary evaporator. The crude product was directly used in the next step with a yield of 95%.

[0039] Synthesis of compound 2

[0040] Compound 1 (18 g, 48 mmol) and anhydrous dichloromethane (100 mL) were added to a 500 mL three-necked flask to fully dissolve, and then boron tribromide (15 g, 60 mmol) was slowly added dropwise under N2 atmosphere at -78 °C. The system was stirred at -78 °C for 1 hour and then heated to room temperature to react overnight. After the reaction was completed, distilled water was slowly added dropwise to quench the reaction, and then washed with sodium carbonate three times. The separated organic phase was washed with water three times and dried with anhydrous magnesium sulfate, and the filtrate was separated by filtration, and the organic solvent was removed by rotary evaporator. 16 g of crude product was obtained, which was directly used in the next step with a yield of 93%.

[0041] Synthesis of compound 3

[0042] The synthesis steps were the same as those of compound 1. 16 g of white solid was obtained with a yield of 70%. 1 H NMR (400MHz, CDCl3): δ7.45(dd,J=6.6Hz,1.9Hz,2H),7.27(d,J=8.4Hz,2H),7.12(td,J=8.7Hz,2.4Hz,1H),6.80-6.75(m,1H),4.06(t,J =6.3Hz,2H),3.45(t,J=6.6Hz,2H),2.55-2.48(m,1H),1.92-1.89(m,8H),1.54-1.47(m,6H),1.32-1.02(m,11H),0.90(t,J=6.9Hz,3H).

[0043] Synthesis of compound SM1

[0044] Compound 3 (3.2 g, 6.04 mmol), 5-bromobenzene-1,2,3-triol (0.36 g, 1.73 mmol), potassium carbonate (1.2 g, 8.65 mmol), and 60 mL of analytically pure acetone solution were added to a 200 mL single-mouth bottle. Nitrogen was passed through and refluxed at 80 ° C for 24 h. After the reaction was completed, it was cooled to room temperature, the solvent was dried, and water was added and extracted with dichloromethane (3×40 mL), washed with water three times, dried over anhydrous magnesium sulfate, filtered and the filtrate was collected, and the solvent was dried. Petroleum ether and dichloromethane (volume ratio 3:2) were used as eluents, and 2.41 g of white solid was obtained by column chromatography, with a yield of 91.4%. 1 H NMR (400MHz, CDCl3) δ7.39(t,J=7.5Hz,6H),7.24(d,J=6.3Hz,6H),7.09–6.98(m,3H),6.79–6.67(m,5H),4.08–4.01(m,6H),3.99–3.91(m,6H) ),2.49(t,J=12.2Hz,3H),1.97–1.70(m,25H),1.58–1.44(m,30H),1.37–1.19(m,29H),1.06(dd,J=23.1,11.2Hz,6H),0.90(t,J=6.9Hz,9H).

[0045] Synthesis of compound SM2

[0046] SM1 (2.3 g, 1.51 mmol), biboronic acid pinacol ester (0.46 g, 1.81 mmol), potassium acetate (0.74 g, 7.53 mmol), [1,1'-bis(diphenylphosphino)ferrocene] palladium dichloride (0.06 g, 0.075 mmol), and 60 mL of analytically pure toluene solution were added to a 200 mL single-mouth bottle. Nitrogen was passed through and refluxed at 110 ° C for 24 h. After the reaction was completed, it was cooled to room temperature, the solvent was dried, and water was added and extracted with dichloromethane (3×40 mL), washed with water three times, dried over anhydrous magnesium sulfate, filtered and the filtrate was collected, and the solvent was dried. Petroleum ether and dichloromethane (volume ratio 1:1) were used as eluents, and 1.2 g of white solid was obtained by column chromatography, with a yield of 50.6%. 1H NMR (400MHz, CDCl3) δ7.46–7.34(m,7H),7.24(d,J=8.0Hz,5H),7.09–6.99(m,5H),6.80–6.69(m,3H),4.03(ddd,J=18.1,12.1,6.4Hz,12H) ,2.49(t,J=11.6Hz,3H),1.99–1.73(m,25H),1.56–1.40(m,14H),1.38–1.19(m,42H),1.05(dd,J=23.7,10.4Hz,6H),0.90(t,J=6.9Hz,9H).

[0047] Synthesis of compound SM3

[0048] 9,10-dihydro-9,9-dimethylacridine (0.47 g, 2.25 mmol), 1-bromo-4-((4-fluorophenyl)sulfonyl)benzene (0.85 g, 2.70 mmol), palladium acetate (0.03 g, 0.12 mmol), tri-tert-butylphosphinofluoroboric acid (0.07 g, 0.23 mmol), sodium tert-butoxide (0.87 g, 9 mmol), and 20 mL of redistilled toluene were added to a 100 mL single-mouth bottle in sequence, and the mixture was heated to 120 ° C under nitrogen protection and refluxed for 24 hours. Cool to room temperature, spin dry the solvent, add water and extract with dichloromethane (3×15 mL), wash three times with water, dry over anhydrous magnesium sulfate, filter and collect the filtrate, and spin dry the solvent. Use petroleum ether and dichloromethane (volume ratio 3:2) as eluents, and separate by column chromatography to obtain 0.74 g of white solid with a yield of 73.2%. 1 H NMR (400MHz, CDCl3) δ8.14(d,J=8.5Hz,2H),8.10–8.04(m,2H),7.54–7.43(m,4H),7.28(d,J=1 .9Hz,1H),7.24(s,1H),6.97(dt,J=9.4,3.6Hz,4H),6.25(dd,J=6.0,3.4Hz,2H),1.65(s,6H).

[0049] Synthesis of compound (R)-SM4

[0050] In a 50mL single-mouth bottle, (R)-6,6'-dibromo-[1,1'-binaphthyl]-2,2'-diol (0.14g, 0.31mmol), SM3 (0.3g, 0.68mmol), cesium carbonate (0.4g, 1.23mmol), and 12mL of anhydrous N,N-dimethylformamide were added in sequence, and the mixture was heated to 100°C under nitrogen protection for 24 hours. After cooling to room temperature, water was added, and then extracted with dichloromethane (3×15mL), washed with water three times, dried over anhydrous magnesium sulfate, filtered and the filtrate was collected, and the solvent was dried by spin drying. With petroleum ether and dichloromethane (volume ratio 3:2) as eluents, 0.31g of white solid was obtained by column chromatography, and the yield was 78.5%. 1 H NMR(400MHz, CDCl3)δ8.08(t,J=5.6Hz,6H),7.90–7.78(m,6H),7.44(ddd,J=11.9,8.7,3.9Hz,10H),7.27(s,1H),7.25(s, 1H),7.14(d,J=9.0Hz,2H),6.96(dd,J=5.9,3.4Hz,8H),6.87(d,J=8.8Hz,4H),6.27–6.19(m,4H),1.65(d,J=5.5Hz,12H).

[0051] Synthesis of compound (S)-SM4

[0052] Its synthetic route and method are the same as those of compound (R)-SM4, except that (R)-6,6'-dibromo-[1,1'-binaphthyl]-2,2'-diol is replaced by (S)-6,6'-dibromo-[1,1'-binaphthyl]-2,2'-diol.

[0053] Synthesis of Compound (R)-1

[0054] In a 50mL single-mouth bottle, (R)-SM4 (0.15g, 0.12mmol), SM2 (0.45g, 0.29mmol), tetrakis(triphenylphosphine)palladium (0.01g, 0.006mmol), 10mL tetrahydrofuran and 3mL of 2mol / L potassium carbonate aqueous solution were added in sequence. The mixture was heated to 80℃ under nitrogen protection and refluxed for 24 hours. After cooling to room temperature, water was added and extracted with dichloromethane (3×15mL), washed with water three times, dried over anhydrous magnesium sulfate, filtered and the filtrate was collected, and the solvent was dried. With petroleum ether and dichloromethane (volume ratio 1:2) as eluents, 0.32g of white solid was obtained by column chromatography, and the yield was 69.4%. 1H NMR(400MHz, CD2Cl2)δ8.02–7.93(m,8H),7.74(d,J=8.7Hz,4H),7.52(d,J=9.2Hz,2H),7.38–7.26(m,22H),7.1 8(dd,J=17.1,8.5Hz,14H),7.01–6.93(m,6H),6.89–6.79(m,16H),6.69(t,J=7.9Hz,6H),6.14–6.08(m,4H),4. 08–3.84(m,24H),2.41(t,J=12.0Hz,6H),1.79(d,J=10.9Hz,40H),1.69(d,J=6.3Hz,4H),1.54(s,12H),1.49(s ,16H),1.46(s,14H),1.43–1.32(m,12H),1.27–1.12(m,52H),0.97(q,J=11.8Hz,12H),0.81(t,J=6.8Hz,18H).

[0055] Synthesis of Compound (S)-1

[0056] Its synthetic route and method are the same as those of compound (R)-1, except that (R)-SM4 is replaced by (S)-SM4.

[0057] Synthesis of compound (R)-SM5

[0058] In a 50mL single-mouth bottle, (R)-6,6'-dibromo-[1,1'-binaphthyl]-2,2'-diol (0.5g, 1.13mmol), 2,3,5,6-tetrafluoroterephthalonitrile (0.23g, 1.13mmol), potassium carbonate (0.31g, 2.25mmol), and 8mL of anhydrous N,N-dimethylformamide were added in sequence. The mixture was reacted at room temperature for 12 hours under nitrogen protection. After monitoring that the reaction was complete, carbazole (0.47g, 2.8mmol) and potassium carbonate (0.78g, 5.63mmol) were added again, and the reaction was stopped for another 12 hours. After adding water, the mixture was extracted with dichloromethane (3×15mL), washed with water three times, dried over anhydrous magnesium sulfate, filtered and the filtrate was collected, and the solvent was spin-dried. 0.56 g of a white solid was obtained by column chromatography using petroleum ether and dichloromethane (volume ratio 1:1) as eluent. The yield was 54.5%. 1HNMR(400MHz, CD2Cl2)δ8.19(d,J=1.9Hz,2H),8.05(d,J=8.9Hz,2H),7.76–7.68(m,4H),7.63(d,J=7.7Hz,2H),7.49(dd,J=9.0,2.0H z,2H),7.31(d,J=9.0Hz,2H),7.22–7.17(m,2H),7.15–7.09(m,4H),6.93(td,J=7.5,1.2Hz,2H),6.77(ddd,J=14.8,11.0,4.5Hz,4H).

[0059] Synthesis of Compound (R)-2

[0060] In a 50mL single-mouth bottle, (R)-SM5 (0.1g, 0.11mmol), SM2 (0.43g, 0.27mmol), tetrakis(triphenylphosphine)palladium (0.01g, 0.006mmol), 10mL tetrahydrofuran and 3mL of 2mol / L potassium carbonate aqueous solution were added in sequence. The mixture was heated to 80℃ and refluxed for 24 hours under nitrogen protection. After cooling to room temperature, water was added and extracted with dichloromethane (3×15mL), washed three times with water, dried over anhydrous magnesium sulfate, filtered and the filtrate was collected, and the solvent was dried by spin drying. With petroleum ether and dichloromethane (volume ratio 1:2) as eluents, 0.22g of white solid was obtained by column chromatography with a yield of 55%. 1 H NMR (400MHz, CD2Cl2) δ8.18(d,J=9.0Hz,4H),7.69(ddd,J=17.1,13.0,7.8Hz,8H),7.56(d,J=8.9Hz ,2H),7.29(dd,J=8.1,1.6Hz,12H),7.24–7.09(m,18H),7.01–6.91(m,8H),6.88(s,4H),6.82–6.65( m,10H),4.07–3.91(m,24H),2.40(ddd,J=12.1,7.4,2.8Hz,6H),1.86–1.69(m,48H),1.59–1.48(m,2 2H),1.37(dd,J=17.4,7.7Hz,12H),1.30–1.09(m,58H),1.03–0.92(m,12H),0.81(t,J=7.0Hz,18H).

[0061] Synthesis of Compound (S)-2

[0062] Its synthetic route and method are the same as those of compound (R)-2, except that (R)-SM5 is replaced by (S)-SM5.

[0063] Example 2

[0064] The compound (R) / (S)-1 in Example 1 was heated at a rate of 20°C per minute in the range of 30-600°C under N2, and a thermogravimetric curve was obtained. Figure 1 It can be seen that the temperatures at which the compound (R) / (S)-1 decomposes to 5% are 384°C and 385°C, respectively.

[0065] Example 3

[0066] The liquid crystal properties of the compound (R) / (S)-1 in Example 1 were studied using a polarizing microscope (POM). Figure 2-3 During the cooling process, it was observed that compound (R) / (S)-1 had obvious birefringence, obvious fluidity during the cooling process, and exhibited a typical smectic liquid crystal striae texture, indicating that compound (R) / (S)-1 may have liquid crystal properties.

[0067] Example 4

[0068] The compound (R) / (S)-1 in Example 1 was subjected to variable temperature X-ray diffraction (XRD) test. Figure 4-5 As shown, the diffraction pattern of compound (R)-1 shows a sharp and intense reflection at 1.97° at 2θ at 164°C, corresponding to In addition, a weak reflection at 2θ of 3.97° (interlaminar spacing of ). The ratio of their interlamellar spacing reciprocals is about 1:2, which is a typical feature of the smectic phase. Compound (S)-1 shows a SAXS pattern similar to that of compound (R)-1, which is ) shows sharp and strong diffraction, and at 4.00° (the layer spacing is ) shows a broad peak, indicating that compound (S)-1 also has the characteristics of smectic phase layered structure.

[0069] Example 5

[0070] The compounds (R) / (S)-1 and (R) / (S)-2 in Example 1 were dissolved in toluene to prepare 10 -5 M solution, and test its UV-visible absorption and photoluminescence spectrum. Figure 6 It can be seen that the UV-visible absorption spectra of compounds (R) / (S)-1 and (R) / (S)-2 in solution have roughly two absorption peaks: the absorption peak at short wavelength (280nm) is mainly attributed to the π-π* transition absorption of the molecule; the absorption peak at long wavelength (310nm) is attributed to the charge transfer (ICT) transition absorption peak from the donor unit to the acceptor unit in the molecule. Figure 2As shown, the maximum emission peak of compound (R) / (S)-1 is 466 nm, which is in the blue light region; the emission peak of compound (R) / (S)-2 is 522 nm, which is in the green light region.

[0071] Example 6

[0072] The photoluminescence performance of the compound (R) / (S)-1 in Example 1 in different solutions was tested. The compound (R) / (S)-1 was dissolved in petroleum ether, n-hexane, dioxane, toluene, triethylamine, ether, ethyl acetate, tetrahydrofuran, dichloromethane, N,N-dimethylformamide, acetone and acetonitrile solutions, and its photoluminescence spectra in different solutions were tested. Figure 7 As shown in the figure, as the polarity of the solvent increases, the three compounds all show obvious solvatochromism, which is a typical sign of the CT characteristics of the corresponding excited state molecules. In addition, compared with the acetonitrile solution, the maximum red shift of compound (R)-1 in the petroleum ether solution is 96nm, and the maximum red shift of compound (S)-1 is 95nm.

[0073] Example 7

[0074] The relationship between the Stokes shift and the solvent polarity parameter of the compound (R) / (S)-1 in Example 1 is plotted according to the Lippert-Mataga solvatochromic model, as shown in FIG. Figure 8 As shown, due to the HLCT characteristics of (R) / (S)-1 in the S1 state, they can also obtain moderate dipole moments (31.16, 31.26 debye) in the excited state.

[0075] Example 8

[0076] The fluorescence lifetime of the compound (R) / (S)-1 in Example 1 in a 10% doped PMMA film was tested under a nitrogen atmosphere. Fig. 9 As shown, the fitting results show that the delay lifetimes of (R) / (S)-1 are 16.6 and 17.2 ns, respectively, both of which are short lifetimes.

[0077] Example 9

[0078] Compound (R)-2 in Example 1 was tested under nitrogen atmosphere for its -5 M fluorescence lifetime in toluene solution, such as Fig.10 As shown, the delayed lifetime of (R)-2 is 53.7 μs after fitting, which is a long lifetime.

[0079] Example 10

[0080] Compound (R)-2 in Example 1 was tested under nitrogen atmosphere for its -5 The variable temperature lifetime spectrum of M in toluene solution, such as Fig.11 As shown, it can be seen that the delay component increases with the increase of temperature, which further proves the TADF characteristics of (R)-2.

[0081] Embodiment 11

[0082] The electroluminescence spectrum of compound (R)-1 in Example 1 in an organic electroluminescent device. Fig.12 As shown, (R)-1 exhibits blue light emission in devices with 0.5, 1.0, and 1.5 wt% doping, and its emission peak is 485 nm.

[0083] Example 12

[0084] The application of compound (R)-1 in Example 1 in organic electroluminescent devices. The compound is used as a dopant in the light-emitting layer of the device to prepare an organic electroluminescent diode with a structure of: ITO / PEDOT:PSS (40nm) / mCP:30wt%CzAcSF:(R)-1 (0.5, 1.0, 1.5wt%) (30nm) / TSPO1 (9nm) / TmPyPB (45nm) / LiF (0.5nm) / Al (120nm). Among them, PEDOT:PSS is a hole injection layer, mCP is the main material of the light-emitting layer, CzAcSF is a sensitizer, TSPO1 is a hole blocking layer, TmPyPB is an electron transport layer, LiF is an electron injection layer, and Al is a cathode. The maximum external quantum efficiency of the device doped with 1wt% is 13.9%, such as Fig.13 shown.

[0085] Example 13

[0086] The electroluminescence spectrum of compound (S)-1 in Example 1 in an organic electroluminescent device. Fig.14 As shown, (S)-1 exhibits blue light emission in devices with 0.5, 1.0, and 1.5 wt% doping, and its emission peak is 485 nm.

[0087] Embodiment 14

[0088] The application of compound (S)-1 in Example 1 in organic electroluminescent devices. The compound is used as a dopant in the light-emitting layer of the device to prepare an organic electroluminescent diode with a structure of: ITO / PEDOT:PSS (40nm) / mCP:30wt%CzAcSF:(S)-1 (0.5, 1.0, 1.5wt%) (30nm) / TSPO1 (9nm) / TmPyPB (45nm) / LiF (0.5nm) / Al (120nm). Among them, PEDOT:PSS is a hole injection layer, mCP is the main material of the light-emitting layer, CzAcSF is a sensitizer, TSPO1 is a hole blocking layer, TmPyPB is an electron transport layer, LiF is an electron injection layer, and Al is a cathode. The maximum external quantum efficiency of the device doped with 1wt% is 17.3%, such as Fig.15 ( Fig.15 (S-1 data).

[0089] Embodiment 15

[0090] The electroluminescence spectrum of compound (R)-2 in Example 1 in an organic electroluminescent device. Fig.16 As shown, (R)-2 exhibits green emission in devices with 10, 20, and 30 wt% doping, and its emission peaks are 514, 534, and 528 nm, respectively.

[0091] Example 16

[0092] The application of the compound (R)-2 in Example 1 in an organic electroluminescent device. The compound is used as a dopant in the light-emitting layer of the device to prepare an organic electroluminescent diode with a structure of: ITO / PEDOT:PSS(40nm) / CzAcSF:10, 20, 30wt% (R)-2(30nm) / TmPyPB(45nm) / LiF(0.5nm) / Al(120nm). Among them, PEDOT:PSS is a hole injection layer, CzAcSF is a main material, TmPyPB is an electron transport layer, LiF is an electron injection layer, and Al is a cathode. The maximum external quantum efficiency of the device doped at 10wt% is 2.53%, as shown in FIG. Fig.17 shown.

Claims

1. A chiral liquid crystal fluorescent material, characterized in that: The fluorescent material structural formula is as follows: 。 2. The use of the chiral liquid crystal fluorescent material according to claim 1, characterized in that: The fluorescent material is used as a dopant for the light-emitting layer of an organic light-emitting diode.

3. The use of the chiral liquid crystal fluorescent material according to claim 2, characterized in that: The structure of the organic light emitting diode is: ITO / hole injection layer PEDOT:PSS / luminescent layer main material mCP: 30 wt% sensitizer CzAcSF: ( R ) / ( S )-1 / hole blocking layer TSPO1 / electron transport layer TmPyPB / electron injection layer LiF / cathode Al.

4. The use of the chiral liquid crystal fluorescent material according to claim 2, characterized in that: The thickness of the light-emitting layer is 30 nm, and the doping amount of the fluorescent material as a dopant is 0.5-1.5 wt %.

5. The use of the chiral liquid crystal fluorescent material according to claim 4, characterized in that: The fluorescent material obtains an organic light emitting diode with an external quantum efficiency of > 10%.

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