A light-emitting circularly polarized light extraction material, a preparation method therefor, and an application thereof

Abstract

The application provides a luminescent circularly polarized light extraction material and a preparation method and application thereof, and belongs to the technical field of organic photoelectric materials and information display. The chiral monomer with a diamino structure and the monomer with a disulfide isothiocyanate group are dissolved in an organic solvent, and then a luminescent circularly polarized light extraction material is obtained through a step-by-step polymerization reaction at normal temperature. The prepared luminescent circularly polarized light extraction material is an optical polymer containing a chiral source and a high-molar polarizability component in a main chain. The material has the ability to induce non-chiral luminescent materials to generate circularly polarized luminescence and excellent light extraction performance, and simultaneously has high transparency and high refractive index characteristics. The application is innovative in that the circularly polarized luminescence induction function and the light extraction function are integrated in a single material system through molecular design, the synergistic enhancement of chiral optical performance and high-refractive light extraction performance is realized, and a new material solution is provided for developing high-efficiency circularly polarized luminescent devices.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic materials and information display technology, specifically a material for extracting luminescent circularly polarized light, its preparation method, and its application. Background Technology

[0002] Circularly polarized luminescent (CPL) materials have attracted much attention due to their enormous application potential in cutting-edge fields such as 3D displays, information encryption, spintronic devices, and biosensing. Currently, the main strategy for obtaining CPLs is to introduce chiral centers into the luminescent system, inducing an asymmetry factor (g) in the luminescent material through chiral transfer. lum However, existing technologies mostly employ physical blending to dope chiral small molecules into polymer matrices or light-emitting layers. This method has significant drawbacks: chiral small molecules are prone to migration and aggregation, leading to phase separation, quenching or inhomogeneity of chiral signals, severely affecting the long-term stability and performance consistency of devices.

[0003] On the other hand, in organic optoelectronic devices (such as OLEDs and QLEDs), the refractive index mismatch between the light-emitting layer and the surrounding air causes a large number of photons to be confined inside the device, significantly reducing the light extraction efficiency. To address this issue, high refractive index (n>1.7) light extraction materials are widely used in devices as optical coupling layers or substrates. However, traditional inorganic light extraction materials (such as TiO2 and ZnS) have poor processability and insufficient flexibility; while organic light extraction materials generally lack chiral optical functions.

[0004] Currently, the circularly polarized light output of devices typically relies on adding a separate circular polarizer on the light-emitting side. This element absorbs most of the light rays with the opposite polarization direction, resulting in a loss of more than 50% of light energy and greatly reducing the energy efficiency of the device.

[0005] Therefore, developing a single material that can integrate chiral emission-inducing function with intrinsic high refractive index light extraction function, enabling it to both induce efficient circularly polarized light and effectively improve light extraction efficiency, is of vital importance for breaking through the performance bottlenecks of next-generation displays and optoelectronic devices. Summary of the Invention

[0006] To provide a novel polymer material that simultaneously possesses a chiral structure and high refractive index and high transparency, this invention discloses a light-emitting circularly polarized light extraction material, its preparation method, and its application. This invention introduces a chiral structure into the polymer backbone through free radical polymerization and appropriately introduces substructures with high molar polarizability to improve the overall refractive index of the material, thereby enabling the material to simultaneously possess a chiral structure and high refractive index and high transparency.

[0007] In a first aspect, the present invention discloses a material for extracting luminescent circularly polarized light, the general structural formula of which is as follows:

[0008] Ar1 is a chiral unit, Ar2 is a unit with an aromatic ring or sulfur element, and the value of n ranges from 7000 to 12000.

[0009] Furthermore, Ar1 is selected from the following structures:

[0010] * indicates a connection point.

[0011] Furthermore, the Ar2 is selected from any of the following structures:

[0012] * indicates a connection point.

[0013] Furthermore, in some embodiments of the present invention, the light-emitting circularly polarized light extraction material has any one of the following structures:

[0014]

[0015]

[0016]

[0017] Secondly, the present invention discloses a method for preparing a luminescent circularly polarized light extraction material. The preparation method is as follows: a chiral monomer with a diamino structure and a monomer with a diisothiocyanate group are dissolved in an organic solvent, and the luminescent circularly polarized light extraction material is obtained by polymerization reaction under room temperature conditions.

[0018] Specifically, the general reaction formula for the process is as follows:

[0019] Furthermore, the preparation method of the luminescent circularly polarized light extraction material includes the following steps: A chiral monomer with a diamino structure and a monomer with a diisothiocyanate group were added to a reaction vessel, and nitrogen was purged 3-4 times. An organic solvent was added and stirred at room temperature for 5 minutes until completely dissolved. After stirring at room temperature for 24 hours, the reaction solution was dropped into methanol to precipitate, filtered, and dried in a vacuum oven to obtain a powder product, which is the luminescent circularly polarized light extraction material.

[0020] Furthermore, the organic solvent is one or more of propylene glycol methyl ether, toluene, hexane, cyclohexane, dioxane, tetrahydrofuran, diethyl ether, acetonitrile, dichloromethane, acetone, chloroform, propylene glycol methyl ether acetate, dimethyl sulfoxide, N,N-dimethylformamide, and 1,2-dichlorobenzene.

[0021] Thirdly, the luminescent circularly polarized light extraction material prepared by this invention can be used in fields such as organic light-emitting diodes (OLEDs), circularly polarized organic light-emitting diodes (CP-OLEDs), 3D display devices, solar cells, quantum dot light-emitting diodes (QLEDs), optical anti-counterfeiting labels, spintronic devices, and biochiral sensors. In these devices, the luminescent circularly polarized light extraction material prepared by this invention is used to prepare an induced circularly polarized light-emitting optical layer. The luminescent circularly polarized light extraction material is mixed with a nematic liquid crystal to prepare the induced circularly polarized light-emitting optical layer.

[0022] Beneficial effects: 1) This invention uses a chiral monomer with a diamino structure and a monomer with a diisothiocyanate group to obtain a chain polymer through free radical polymerization. By adding a chiral structure to the main chain and appropriately adding a substructure with high molar polarizability, the chiral structure and high refractive index properties are well combined, so that the material can simultaneously possess the excellent properties of induced circularly polarized luminescence, high refractive index and high transparency.

[0023] 2) In the prior art, chiral small molecules are often doped into the polymer matrix or light-emitting layer by physical blending. This method is prone to migration and aggregation of chiral small molecules, which affects the long-term stability and performance consistency of the device. This invention overcomes this problem.

[0024] 3) This invention overcomes the problem that organic light extraction materials generally lack chiral optical functions.

[0025] 4) The material prepared in this invention is a single material that integrates chiral emission induction function with intrinsic high refractive index light extraction function. This allows it to both induce highly efficient circularly polarized light and effectively improve light extraction efficiency, which is of crucial significance for overcoming the performance bottlenecks of next-generation displays and optoelectronic devices. This type of circularly polarized emission extraction material can be applied in fields such as circularly polarized organic light-emitting diodes, 3D display devices, quantum dot light-emitting diodes, solar cells, optical anti-counterfeiting labels, spintronic devices, and biochiral sensors. Attached Figure Description

[0026] Figure 1 The refractive index diagram of polymer P1 obtained in Example 1 of the present invention is shown. As can be seen from the ellipsometer test, the average refractive index in the visible light region is 1.79.

[0027] Figure 2The refractive index diagram of polymer P2 obtained in Example 2 of the present invention shows that the average refractive index in the visible light region is 1.93, as determined by ellipsometer testing.

[0028] Figure 3 The refractive index diagram of polymer P3 obtained in Example 3 of the present invention shows that the average refractive index in the visible light region is 1.76, as determined by ellipsometer testing.

[0029] Figure 4 The refractive index diagram of polymer P4 obtained in Example 4 of the present invention is shown. As can be seen from the ellipsometer test, the average refractive index in the visible light region is 1.69.

[0030] Figure 5 The diagram shows the asymmetry factor of the circularly polarized light emitted by the P1 chiral polymer-induced OLED obtained in Example 1 of this invention. The device structure is P1 / GLASS / ITO / PEDOT:PSS / Super Yellow / TPBi / LiF / Al.

[0031] Figure 6 The diagram shows the asymmetry factor of the circularly polarized light emitted by the P2 chiral polymer-induced OLED obtained in Example 2 of this invention. The device structure is P2 / GLASS / ITO / PEDOT:PSS / Super Yellow / TPBi / LiF / Al.

[0032] Figure 7 The image shows the transparency of polymer P1 obtained in Example 1 of this invention, as measured by a UV-Vis spectrophotometer. Detailed Implementation

[0033] The technical solution of the present invention will be described in detail below through embodiments, but the scope of protection of the present invention is not limited to the embodiments described.

[0034] Example 1 Select Ar1 as Ar2 is The preparation process of the luminescent circularly polarized light extraction material P1 is as follows:

[0035] The monomers containing Ar2 (2.0 mmol, 1 equiv.) and Ar1 (2.0 mmol, 1 equiv.) were added to the reaction vessel, and the nitrogen atmosphere was purged 3-4 times. Dimethyl sulfoxide (15 mL) was added, and the mixture was stirred at room temperature for 5 minutes until completely dissolved. After stirring at room temperature for 24 hours, the reaction solution was added dropwise to methanol (500 mL) to precipitate. After filtration, the solution was dried in a vacuum oven to obtain a white powder product P1 with a yield of 97%. By comparing OLED devices with and without the light extraction layer, it was found that the luminous efficiency of the light extraction layer was increased by 10%, where n ranged from 7000 to 12000.

[0036] Figure 1 The refractive index diagram of polymer P1 obtained in Example 1 of the present invention is shown. As can be seen from the ellipsometer test, the average refractive index in the visible light region is 1.79.

[0037] Figure 5 The diagram shows the asymmetry factor of the circularly polarized light emitted by the OLED induced by the chiral polymer P1 obtained in Example 1 of this invention. The asymmetry factor glum reflects the difference in intensity of left-hand and right-hand circularly polarized light during the emission process of the chiral compound. The device structure is P1 / GLASS / ITO / PEDOT:PSS / Super Yellow / TPBi / LiF / Al, where P1 represents the circularly polarized light inducing layer.

[0038] Figure 7 The image shows the transparency of polymer P1 obtained in Example 1 of this invention, as measured by a UV-Vis spectrophotometer.

[0039] Example 2 Select Ar1 as Ar2 is The preparation process of the luminescent circularly polarized light extraction material P2 is as follows:

[0040] The monomers containing Ar2 (1.4 mmol, 1 equiv.) and Ar1 (1.4 mmol, 1 equiv.) were added to the reaction vessel, and the nitrogen atmosphere was purged 3-4 times. Chloroform (17 mL) was added, and the mixture was stirred at room temperature for 5 minutes until completely dissolved. After stirring at room temperature for 24 hours, the reaction solution was added dropwise to methanol (500 mL) to precipitate. After filtration, the solution was dried in a vacuum oven to obtain a white powder product P2 with a yield of 93%. By comparing OLED devices with and without the light extraction layer, it was found that the luminous efficiency of the light extraction layer was increased by 12%, where n ranged from 7000 to 12000.

[0041] Figure 2 The refractive index diagram of polymer P2 obtained in Example 2 of the present invention shows that the average refractive index in the visible light region is 1.93, as determined by ellipsometer testing.

[0042] Figure 6 The diagram shows the asymmetry factor of the circularly polarized light emitted by the P2 chiral polymer-induced OLED obtained in Example 2 of this invention. The asymmetry factor glum reflects the difference in intensity of left- and right-handed circularly polarized light during the emission process of the chiral compound. The device structure is P2 / GLASS / ITO / PEDOT:PSS / Super Yellow / TPBi / LiF / Al.

[0043] Example 3 Select Ar1 as Ar2 is The preparation process of the luminescent circularly polarized light extraction material P3 is as follows:

[0044] The monomers containing Ar2 (1.3 mmol, 1 equiv.) and Ar1 (1.3 mmol, 1 equiv.) were added to the reaction vessel, and the nitrogen atmosphere was purged 3-4 times. Tetrahydrofuran (10 mL) was added, and the mixture was stirred at room temperature for 5 minutes until completely dissolved. After stirring at room temperature for 24 hours, the reaction solution was added dropwise to cyclohexane (500 mL) to settle. After filtration, the solution was dried in a vacuum oven to obtain a white powder product P3 with a yield of 91%. By comparing OLED devices with and without the light extraction layer, it was found that the luminous efficiency of the light extraction layer was increased by 11%, where n ranged from 7000 to 12000.

[0045] Figure 3 The refractive index diagram of polymer P3 obtained in Example 3 of the present invention shows that the average refractive index in the visible light region is 1.76, as determined by ellipsometer testing.

[0046] Example 4 Select Ar1 as Ar2 is The preparation process of the luminescent circularly polarized light extraction material P4 is as follows:

[0047] A monomer containing Ar2 (1.0 mmol, 1 equiv.) and a monomer containing Ar1 (1.0 mmol, 1 equiv.) were added to the reaction vessel, and the nitrogen atmosphere was purged 3-4 times. Dioxane (15 mL) was added, and the mixture was stirred at room temperature for 5 minutes until completely dissolved. After stirring at room temperature for 24 hours, the reaction solution was added dropwise to methanol (500 mL) to precipitate. After filtration, the solution was dried in a vacuum oven to obtain a white powder product P4 with a yield of 90%. By comparing OLED devices with and without the light extraction layer, it was found that the luminous efficiency of the light extraction layer was increased by 18%, where n ranged from 7000 to 12000.

[0048] Figure 4 The refractive index diagram of polymer P4 obtained in Example 4 of the present invention is shown. As can be seen from the ellipsometer test, the average refractive index in the visible light region is 1.69.

[0049] Example 5 Select Ar1 as Ar2 is The preparation process of the luminescent circularly polarized light extraction material P5 is as follows:

[0050] The monomers containing Ar2 (1.5 mmol, 1 equiv.) and Ar1 (1.5 mmol, 1 equiv.) were added to the reaction vessel, and the nitrogen atmosphere was purged 3-4 times. Dichloromethane (17 mL) was added, and the mixture was stirred at room temperature for 5 minutes until completely dissolved. After stirring at room temperature for 24 hours, the reaction solution was added dropwise to methanol (500 mL) to precipitate. After filtration, the solution was dried in a vacuum oven to obtain a white powder product P5 with a yield of 93%. By comparing OLED devices with and without the light extraction layer, it was found that the luminous efficiency of the light extraction layer was increased by 14%, where n ranged from 7000 to 12000.

[0051] Example 6 Select Ar1 as Ar2 is The preparation process of the luminescent circularly polarized light extraction material P6 is as follows:

[0052] The monomers containing Ar2 (1.0 mmol, 1 equiv.) and Ar1 (1.0 mmol, 1 equiv.) were added to the reaction vessel, and the nitrogen atmosphere was purged 3-4 times. Dimethyl sulfoxide (14 mL) was added, and the mixture was stirred at room temperature for 5 minutes until completely dissolved. After stirring at room temperature for 24 hours, the reaction solution was added dropwise to hexane (500 mL) to settle. After filtration, the solution was dried in a vacuum oven to obtain a white powder product P6 with a yield of 92%. By comparing OLED devices with and without the light extraction layer, it was found that the luminous efficiency of the light extraction layer was increased by 13%, where n ranged from 7000 to 12000.

[0053] Example 7 Select Ar1 as Ar2 is The preparation process of the luminescent circularly polarized light extraction material P7 is as follows:

[0054] The monomers containing Ar2 (2.0 mmol, 1 equiv.) and Ar1 (2.0 mmol, 1 equiv.) were added to the reaction vessel, and the nitrogen atmosphere was purged 3-4 times. Propylene glycol methyl ether (20 mL) was added, and the mixture was stirred at room temperature for 5 minutes until completely dissolved. After stirring at room temperature for 24 hours, the reaction solution was added dropwise to methanol (500 mL) to precipitate. After filtration, the solution was dried in a vacuum oven to obtain a white powder product P7 with a yield of 94%. By comparing OLED devices with and without the light extraction layer, it was found that the luminous efficiency of the light extraction layer was increased by 11%, where n ranged from 7000 to 12000.

[0055] Example 8 Select Ar1 as Ar2 is The preparation process of the luminescent circularly polarized light extraction material P8 is as follows:

[0056] The monomers containing Ar2 (2.4 mmol, 1 equiv.) and Ar1 (2.4 mmol, 1 equiv.) were added to the reaction vessel, and the nitrogen atmosphere was purged 3-4 times. Propylene glycol methyl ether acetate (20 mL) was added, and the mixture was stirred at room temperature for 5 minutes until completely dissolved. After stirring at room temperature for 24 hours, the reaction solution was added dropwise to methanol (500 mL) to precipitate. After filtration, the solution was dried in a vacuum oven to obtain a white powder product P8 with a yield of 95%. By comparing OLED devices with and without the light extraction layer, it was found that the luminous efficiency of the light extraction layer was increased by 13%, where n ranged from 7000 to 12000.

[0057] Example 9 Select Ar1 as Ar2 is The preparation process of the luminescent circularly polarized light extraction material P9 is as follows:

[0058] The monomers containing Ar2 (3.0 mmol, 1 equiv.) and Ar1 (3.0 mmol, 1 equiv.) were added to the reaction vessel, and the nitrogen atmosphere was purged 3-4 times. N,N-dimethylamide (15 mL) was added, and the mixture was stirred at room temperature for 5 minutes until completely dissolved. After stirring at room temperature for 24 hours, the reaction solution was added dropwise to methanol (500 mL) to settle. After filtration, the solution was dried in a vacuum oven to obtain a white powder product P9 with a yield of 92%. Comparison between OLED devices containing the light extraction layer and those without showed that the luminous efficiency of the light extraction layer was increased by 19%, where n ranged from 7000 to 12000.

[0059] This invention involves dissolving a chiral monomer with a diamino structure and a monomer with a diisothiocyanate group in an organic solvent, and then performing a stepwise polymerization reaction at room temperature to obtain a luminescent circularly polarized light extraction material. The prepared luminescent circularly polarized light extraction material is an optical polymer with a chiral source and a high molar polarizability component in its main chain. This material possesses the ability to induce circularly polarized luminescence in chiral luminescent materials and exhibits excellent light extraction performance, while also possessing high transparency and high refractive index characteristics.

[0060] The innovation of this invention lies in integrating circularly polarized light emission induction and light extraction functions into a single material system through molecular design. This achieves a synergistic enhancement of chiral optical properties and high-refractive-index light extraction performance, providing a new material solution for developing high-efficiency circularly polarized light-emitting devices. This material has broad application prospects in fields such as circularly polarized organic light-emitting diodes, 3D display devices, quantum dot light-emitting diodes, optical anti-counterfeiting labels, solar cells, spintronic devices, and biochiral sensing.

[0061] As described above, although the invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the invention itself. Various changes in form and detail may be made without departing from the spirit and scope of the invention.

Claims

1. A material for extracting luminescent circularly polarized light, characterized in that, The general structural formula of the luminescent circularly polarized light extraction material is as follows: ； Ar1 is a chiral unit, Ar2 is a unit with an aromatic ring or sulfur element, and the value of n ranges from 7000 to 12000. The structure of Ar1 is as follows: ； * indicates a connection point.

2. The luminescent circularly polarized light extraction material according to claim 1, characterized in that, The Ar2 is selected from any of the following structures: ； * indicates a connection point.

3. The luminescent circularly polarized light extraction material according to claim 1, characterized in that, The luminescent circularly polarized light extraction material is selected from any one of the following structures: ； ； 。 4. The method for preparing the luminescent circularly polarized light extraction material according to any one of claims 1 to 3, characterized in that, A material for extracting luminescent circularly polarized light is obtained by dissolving a chiral monomer with a diamino structure and a monomer with a diisothiocyanate group in an organic solvent and then polymerizing them at room temperature.

5. The preparation method according to claim 4, characterized in that, The preparation method of the luminescent circularly polarized light extraction material specifically includes the following steps: A chiral monomer with a diamino structure and a monomer with a diisothiocyanate group were added to a reaction vessel, and nitrogen was purged 3-4 times. An organic solvent was added and stirred at room temperature for 5 minutes until completely dissolved. After stirring at room temperature for 24 hours, the reaction solution was dropped into methanol to precipitate, filtered, and dried in a vacuum oven to obtain a powder product, which is the luminescent circularly polarized light extraction material.

6. The preparation method according to claim 4, characterized in that, The organic solvent is one or more of propylene glycol methyl ether, toluene, hexane, cyclohexane, dioxane, tetrahydrofuran, diethyl ether, acetonitrile, dichloromethane, acetone, chloroform, propylene glycol methyl ether acetate, dimethyl sulfoxide, N,N-dimethylformamide, and 1,2-dichlorobenzene.

7. The application of the luminescent circularly polarized light extraction material according to any one of claims 1 to 3 in organic light-emitting diodes, circularly polarized organic light-emitting diodes, 3D display devices, solar cells, quantum dot light-emitting diodes, optical anti-counterfeiting labels, spintronic devices, or biochiral sensors.

8. The luminescent circularly polarized light extraction material according to any one of claims 1 to 3 is used to prepare an induced circularly polarized light emission optical layer after being mixed with a nematic liquid crystal.

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