Three-dimensional printing circular polarization luminescent material and preparation method and application thereof

Abstract

The invention is suitable for the technical field of luminescent materials, and provides a three-dimensional printing circular polarization luminescent material and a preparation method and application thereof, the material comprises a chiral functional material, a luminescent component and an inorganic filler; wherein the chiral functional material is formed by free radical polymerization of a cholesteric liquid crystal precursor, a photocurable monomer and a photoinitiator, and the cholesteric liquid crystal precursor is formed by compounding nematic liquid crystal and a chiral agent. The chiral functional material disclosed by the invention forms a spatial continuous structure in a photocuring process, and keeps a spiral superstructure self-assembled by chiral liquid crystals; the fluorescent light-emitting component is dispersed in the fluorescent powder and can emit left / right-handed circularly polarized light under light excitation; the inorganic filler is uniformly distributed in the system and is used for improving the optical appearance, the mechanical property and the stability of the material. According to the invention, a functional device with a complex structure and stable circular polarization luminescence performance can be obtained only by introducing the inorganic nanofiller into the chiral luminescent ink and directly forming through photocuring three-dimensional printing.

Description

Technical Field

[0001] This invention belongs to the field of luminescent materials technology, and particularly relates to a three-dimensional printed circularly polarized luminescent material, its preparation method, and its application. Background Technology

[0002] Circularly polarized luminescence (CPL) materials are a class of functional materials capable of emitting chiral light, and they have significant application value in fields such as 3D displays, quantum communication, information encryption, holographic storage, and spintronics. Currently, most CPL materials exist in the form of thin films or solutions, resulting in limited fabrication morphologies and making it difficult to directly process them into complex 3D structures, thus restricting their integration and application in practical devices.

[0003] In recent years, the development of 3D printing technology has provided new possibilities for the construction of CPL materials, especially 3D printing technology based on photopolymerization, which can achieve high-precision and rapid 3D molding and has significant advantages in the processing of complex structures. However, the currently disclosed CPL material printing systems have the following shortcomings: poor material compatibility, commonly used photosensitive resin systems lack circularly polarized light emission function, making it difficult to achieve both excellent molding performance and chiral optical properties; insufficient display effect, structures printed by traditional CPL materials often have a transparent appearance, lacking diffuse reflection and surface gloss, making them difficult to distinguish from the background environment in display applications, resulting in insufficient optical contrast and thus reducing the visibility and recognizability of patterns or devices; and imperfect preparation process, some reported 3D CPL materials require complex subsequent processing steps to achieve stable light emission, which is not conducive to widespread application.

[0004] Inorganic fillers, as common polymer composite modifiers, have been widely used in optical resins, decorative coatings, and functional films, primarily to improve the appearance and optical properties of materials. Addressing the shortcomings in the appearance and display effects of current CPL materials in 3D printing applications, introducing appropriate amounts of inorganic fillers into photosensitive resin systems can effectively enhance the surface gloss and visual depth of printed products, expanding their application value in high-end displays, optical devices, and decorative functional components. Therefore, developing a circularly polarized light-emitting material modified with inorganic fillers that can be directly 3D printed can not only overcome the shortcomings of existing technologies but also expand the application value of CPL materials in high-end displays and optical devices. Summary of the Invention

[0005] The purpose of this invention is to provide a three-dimensional printed circularly polarized light-emitting material, which aims to solve the problems mentioned in the background art.

[0006] The present invention is implemented as follows: a three-dimensional printed circularly polarized luminescent material, the material comprising a chiral functional material, a luminescent component, and an inorganic filler;

[0007] The chiral functional material is formed by free radical polymerization of a cholesteric liquid crystal precursor, a photocurable monomer, and a photoinitiator. The cholesteric liquid crystal precursor is composed of a nematic liquid crystal and a chiral agent.

[0008] Another objective of this invention is to provide a three-dimensional printed circularly polarized light-emitting material, comprising the following steps:

[0009] A mixture of 4-cyano-4′-pentylbiphenyl was compounded with (R / S)-4-(2-methylbutoxy)biphenyl, and a luminescent component was added. The mixture was stirred evenly under heating conditions for a certain period of time to obtain a cholesteric liquid crystal precursor.

[0010] A photocurable monomer and a photoinitiator were added to a cholesteric liquid crystal precursor and stirred evenly under light-protected conditions to obtain a chiral luminescent ink.

[0011] Inorganic fillers were added to chiral luminescent ink, and the ink was ultrasonicated under light-protected conditions to obtain chiral luminescent printing ink modified with inorganic fillers.

[0012] The three-dimensional printed circularly polarized luminescent material is obtained by using a photopolymerization 3D printing device to solidify the inorganic filler-modified chiral luminescent printing ink layer by layer.

[0013] Another objective of this invention is to provide an application of three-dimensional printed circularly polarized light-emitting materials in optical devices, three-dimensional displays, quantum communication, information encryption, holographic storage, and spintronics.

[0014] The embodiments of the present invention utilize photopolymerization 3D printing technology to achieve the molding of complex three-dimensional structures with a resolution of 10μm, breaking through the limitation that traditional circularly polarized light-emitting materials can only be prepared in thin film or solution state;

[0015] By introducing inorganic nanofillers, its optical appearance is improved, its gloss is significantly enhanced, and its optical appearance is more uniform and bright.

[0016] The three-dimensional structure prepared in the embodiments of the present invention can maintain stable and high-performance CPL output at different spatial angles, ensuring the applicability of the device application;

[0017] The embodiments of the present invention take into account both optical functions and the fabrication of complex structures, and have broad application prospects in quantum optical devices, three-dimensional optical displays and integrated optoelectronic systems. Attached Figure Description

[0018] Figure 1This is a schematic diagram of the fabrication process of the three-dimensional printed circularly polarized light-emitting material provided in Embodiment 1 of the present invention;

[0019] Figure 2 POM characterization of the cholesteric liquid crystal precursor provided in Example 1 of the present invention;

[0020] Figure 3 Photographs of the chiral polymer inks provided in Embodiment 1 and Comparative Example 1 of the present invention;

[0021] Figure 4 CPL characterization of the three-dimensional printed circularly polarized light-emitting material prepared using R5011 as provided in Embodiment 1 of the present invention;

[0022] Figure 5 CPL characterization of the three-dimensional printed circularly polarized light-emitting material prepared using S5011 as provided in Embodiment 7 of the present invention;

[0023] Figure 6 These are photographs of various three-dimensional printed circularly polarized light-emitting devices provided in Embodiment 1 of the present invention;

[0024] Figure 7 The calculation of the emission intensity difference g for the three-dimensional printed circularly polarized light-emitting material provided in Embodiment 1 of the present invention. lum value;

[0025] Figure 8 A high-resolution photograph of the three-dimensionally printed circularly polarized light-emitting material provided in Embodiment 1 of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] A three-dimensional printed circularly polarized light-emitting material, comprising a chiral functional material, a light-emitting component (the light-emitting component is dispersed in the chiral functional material) and an inorganic filler, is directly formed into a three-dimensional structure under photopolymerization 3D printing process, achieving a unity of high asymmetric light-emitting factor value, high stability and complex spatial structure construction, and can emit left / right circularly polarized light at different thicknesses;

[0028] The chiral functional material is formed by free radical polymerization of a cholesteric liquid crystal precursor, a photocurable monomer, and a photoinitiator. It forms a spatially continuous structure through photocuring, and the resulting helical superstructure can be maintained after curing. When the luminescent component is excited by ultraviolet light, it emits light with circular polarization characteristics. The cholesteric liquid crystal precursor is composed of a nematic liquid crystal and a chiral agent.

[0029] The nematic liquid crystal is a mixture of 4-cyano-4′-pentylbiphenyl; the chiral agent is (R / S)-4-(2-methylbutoxy)biphenyl.

[0030] The photocurable monomer is an acrylic or methacrylic monomer; more preferably, it is a multifunctional acrylic monomer with crosslinking properties.

[0031] The photoinitiator is a phosphonooxy photoinitiator or an α-hydroxy ketone photoinitiator; more preferably, it is a phosphonooxy photoinitiator.

[0032] The luminescent component is one of coumarin, carbazole, or rhodamine fluorescent dyes; more preferably, it is a coumarin fluorescent dye, which has high fluorescence quantum efficiency and excellent photostability, and good compatibility with chiral liquid crystal systems.

[0033] The inorganic filler is at least one of titanium dioxide nanoparticles, silicon dioxide nanoparticles, and zinc oxide nanoparticles.

[0034] A three-dimensional printed circularly polarized luminescent material includes the following steps:

[0035] A mixture of 4-cyano-4′-pentylbiphenyl (E7) and (R / S)-4-(2-methylbutoxy)biphenyl (R / S5011) was compounded, and a luminescent component (coumarin 7 could be selected) was added. The mixture was stirred evenly under heating conditions for a certain period of time to obtain a cholesteric liquid crystal precursor.

[0036] A photocurable monomer (a mixed acrylic monomer, which is obtained by compounding branched polyester polyurethane acrylate, octadecyl acrylate, hydroxyethyl methacrylate and cyclopentadiene acrylate) and a photoinitiator (2-hydroxy-2-methyl-1-phenyl-1-propanone (TPO)) are added to a cholesteric liquid crystal precursor and stirred evenly under light-protected conditions to obtain a chiral luminescent ink.

[0037] Inorganic fillers were added to chiral luminescent ink, and the ink was ultrasonicated under light-protected conditions to obtain chiral luminescent printing ink modified with inorganic fillers.

[0038] The three-dimensional printed circularly polarized luminescent material was obtained by using a photopolymerization 3D printing device to solidify layer by layer an inorganic filler-modified chiral luminescent printing ink.

[0039] The mass ratio of the 4-cyano-4′-pentylbiphenyl mixture, (R / S)-4-(2-methylbutoxy)biphenyl, and the luminescent component is 96.24:2.77:0.99;

[0040] The chiral luminescent ink contains 30-60% photocurable monomer and 1% photoinitiator by mass.

[0041] The amount of inorganic filler added is 1% of the chiral luminescent ink, and the particle size range is 20-200nm.

[0042] Preferably, in the step of layer-by-layer curing, the thickness of a single layer is 10 μm, the curing time is 20 s, and the exposure light intensity is 50 mW / cm². 2 .

[0043] This invention utilizes the synergistic effect of chiral liquid crystal superstructure and inorganic nanofillers to enhance the CPL signal. Three-dimensional devices with complex spatial morphology and stable circularly polarized light emission performance can be fabricated using high-resolution projection micro-stereolithography. These devices feature simple fabrication processes, scalable fabrication, high design freedom and complexity, high material forming precision, excellent CPL performance, and omnidirectional CPL light emission. They can be widely applied to high-resolution three-dimensional optical display devices, quantum optical devices, and integrated optoelectronic systems.

[0044] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0045] Example 1: A three-dimensional printed circularly polarized luminescent material, the preparation process of which is as follows: Figure 1 As shown, the specific steps include:

[0046] (1) Preparation of cholesteric liquid crystal precursor (chiral liquid crystal precursor): Weigh 9.72 g of 4-cyano-4′-pentylbiphenyl mixture (E7), 0.28 g of (R)-4-(2-methylbutoxy)biphenyl (R5011), and 0.1 g of coumarin 7. Stir thoroughly under heating conditions until the solution is clear to obtain 10 g of chiral liquid crystal precursor;

[0047] (2) Preparation of chiral luminescent ink: Add 15 g of mixed acrylic monomers (branched polyester polyurethane acrylate, octadecyl acrylate, hydroxyethyl methacrylate and cyclopentadiene acrylate in a mass ratio of 1:1:1:1) and 0.253 g of photoinitiator TPO to the above chiral liquid crystal precursor, stir at room temperature until the solution is clear and uniform, and obtain a circularly polarized luminescent ink that can be used for photopolymerization 3D printing;

[0048] (3) Introduction of inorganic fillers: 0.25 g of TiO2 nanoparticles with a particle size of about 50 nm were added to the above-mentioned photocurable 3D printed circularly polarized luminescent ink, and after ultrasonication, a transparent and uniform nanocomposite chiral luminescent ink was formed.

[0049] (4) Photopolymerization 3D printing process: Inject the ink obtained in step (3) into the resin tank of the photopolymerization 3D printing equipment, set the exposure wavelength to 405 nm, the layer thickness to 10 μm, and the exposure intensity to 50 mW / cm².2 The CPL three-dimensional structural parts were prepared by a layer-by-layer exposure curing method with an exposure time of 20 s.

[0050] Example 2 differs from Example 1 only in that, in step (3), the inorganic filler added is SiO2 nanoparticles with a particle size of about 50 nm.

[0051] Example 3 differs from Example 1 only in that, in step (3), the inorganic filler added is ZnO nanoparticles with a particle size of about 50 nm.

[0052] Example 4 differs from Example 1 only in that, in step (2), the mass ratio of the mixed acrylic monomer to the cholesteric liquid crystal precursor is adjusted to 3:7.

[0053] Example 5 differs from Example 1 only in that, in step (2), the mass ratio of the mixed acrylic monomer to the cholesteric liquid crystal precursor is adjusted to 1:1.

[0054] Example 6 differs from Example 1 only in that, in step (2), the mass ratio of the mixed acrylic monomer to the cholesteric liquid crystal precursor is adjusted to 6:4.

[0055] Example 7 differs from Example 1 only in that, in step (1), R5011 is replaced with S5011.

[0056] The only difference between Comparative Example 1 and Example 1 is that step (3) is not performed.

[0057] Performance characterization:

[0058] The cholesteric liquid crystal precursor prepared in Example 1 was characterized, and the POM characterization was as follows: Figure 2 As shown, the precursor system exhibits a typical chiral liquid crystal helical structure, indicating that it has a good molecular ordered orientation structure, which provides a foundation for the superior luminescence performance of subsequent 3D circularly polarized materials.

[0059] The chiral polymer inks prepared in Example 1 with added TiO2 nanoparticles and those without added TiO2 nanoparticles, respectively, were analyzed, and the resulting images are shown below. Figure 3 As shown in the figure, the system obtained after adding inorganic filler showed a significant improvement in appearance compared to the system without filler, indicating that the introduction of TiO2 nanoparticles can improve the surface gloss and visual effect of the printing material.

[0060] The 3D-printed circularly polarized luminescent materials prepared using R5011 and S5011 in Examples 1 and 7, respectively, were characterized, and the CPL characterization results are as follows: Figure 4 , 5As shown in the figure, the two exhibit mirror-image CPL signals, and chiral luminescence characteristics can be detected at different thicknesses of the printed samples (ranging from 150 μm to 2 mm), indicating that the material prepared in the embodiments of the present invention can maintain chiral luminescence behavior after 3D printing with different numbers of layers.

[0061] Photographs of various 3D-printed circularly polarized light-emitting devices obtained based on Example 1 are shown below. Figure 6 As shown in the figure, the ink prepared in the embodiment of the present invention can achieve the molding of complex structures (cubes, chess pieces, iconic patterns, etc.), and the molding materials all maintain bright luminescent properties, indicating that the system has good printing adaptability and molding stability.

[0062] The emission intensity difference g was calculated by detecting the material prepared in Example 1 in a circumferential direction of 60°–360° using a fiber optic spectrometer. lum The result of the value is as follows Figure 7 As shown in the figure, the obtained circularly polarized luminescent material exhibits a stable optical response under omnidirectional detection, and its g lum The values ​​are basically consistent at different angles, proving that the system has excellent isotropic CPL output characteristics;

[0063] High-resolution photograph of the 3D-printed circularly polarized luminescent material prepared in Example 1 is shown below. Figure 8 As shown in the figure, the embodiments of the present invention can achieve microstructure printing with a maximum precision of about 10 micrometers, proving its potential application value in the field of high-resolution photopolymerization printing.

[0064] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A three-dimensional printed circularly polarized luminescent material, characterized in that, The material includes chiral functional materials, luminescent components, and inorganic fillers; The chiral functional material is formed by free radical polymerization of a cholesteric liquid crystal precursor, a photocurable monomer, and a photoinitiator. The cholesteric liquid crystal precursor is composed of a nematic liquid crystal and a chiral agent.

2. The three-dimensional printed circularly polarized light-emitting material according to claim 1, characterized in that, The nematic liquid crystal is a mixture of 4-cyano-4′-pentylbiphenyl; the chiral agent is (R / S)-4-(2-methylbutoxy)biphenyl.

3. The three-dimensional printed circularly polarized light-emitting material according to claim 1, characterized in that, The photocurable monomer is an acrylic or methacrylic monomer.

4. The three-dimensional printed circularly polarized light-emitting material according to claim 1, characterized in that, The photoinitiator is a phosphonooxy photoinitiator or an α-hydroxy ketone photoinitiator.

5. The three-dimensional printed circularly polarized light-emitting material according to claim 1, characterized in that, The luminescent component is one of the following: coumarin, carbazole, or rhodamine fluorescent dyes.

6. The three-dimensional printed circularly polarized light-emitting material according to claim 1, characterized in that, The inorganic filler is at least one of titanium dioxide nanoparticles, silicon dioxide nanoparticles, and zinc oxide nanoparticles.

7. A three-dimensional printed circularly polarized light-emitting material as described in any one of claims 1-6, characterized in that, Includes the following steps: A mixture of 4-cyano-4′-pentylbiphenyl was compounded with (R / S)-4-(2-methylbutoxy)biphenyl, and a luminescent component was added. The mixture was stirred evenly under heating conditions for a certain period of time to obtain a cholesteric liquid crystal precursor. A photocurable monomer and a photoinitiator were added to a cholesteric liquid crystal precursor and stirred evenly under light-protected conditions to obtain a chiral luminescent ink. Inorganic fillers were added to chiral luminescent ink, and the ink was ultrasonicated under light-protected conditions to obtain chiral luminescent printing ink modified with inorganic fillers. The three-dimensional printed circularly polarized luminescent material is obtained by using a photopolymerization 3D printing device to solidify the inorganic filler-modified chiral luminescent printing ink layer by layer.

8. The method for preparing a three-dimensional printed circularly polarized luminescent material according to claim 7, characterized in that, The mass ratio of the 4-cyano-4′-pentylbiphenyl mixture, (R / S)-4-(2-methylbutoxy)biphenyl, and the luminescent component is 96.24:2.77:0.99; The chiral luminescent ink contains 30-60% photocurable monomer and 1% photoinitiator by mass. The amount of inorganic filler added is 1% of the chiral luminescent ink, and the particle size range is 20-200nm.

9. The method for preparing a three-dimensional printed circularly polarized luminescent material according to claim 7, characterized in that, In the layer-by-layer curing step, the thickness of a single layer is 10 μm, the curing time is 20 s, and the exposure light intensity is 50 mW / cm². 2 .

10. The application of a three-dimensional printed circularly polarized light-emitting material as described in any one of claims 1-6 in optical devices, three-dimensional displays, quantum communication, information encryption, holographic storage, and spintronics.

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