Intrinsic stretchable alternating current electroluminescent device and preparation method thereof
By interacting with the multifunctional acrylate block copolymer with BTO ceramic particles, a composite elastomer with high dielectric constant is prepared, which solves the contradiction between high tensileability and high brightness of traditional electroluminescent materials, and realizes the high-performance application of fully flexible electroluminescent devices.
Patent Information
- Application Number
- CN202510679708.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-26
- Publication Date
- 2025-09-05
AI Technical Summary
Traditional electroluminescent materials cannot take into account high luminescence brightness, low operating voltage and high tensileability. While the existing methods improve the dielectric constant, there are problems such as increased equipment loss, material unevenness and environmental hazards.
The multifunctional acrylate block copolymer interacts with BTO ceramic particles to form a composite elastomer with high dielectric constant. Fully flexible electroluminescent devices are prepared by thermal lamination to eliminate interlayer interfaces and improve interface polarization capabilities and mechanical stability.
The balance between high photoelectric performance and high tensileability has been achieved, and fully flexible, mechanically stable electroluminescent devices are prepared, suitable for wearable electronic display screens, flexible lighting and strain sensors.
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Figure CN120603094A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of flexible luminescent materials, and in particular to an intrinsically stretchable alternating current electroluminescent device and a preparation method thereof. Background Art
[0002] Electroluminescence (EL), the phenomenon of converting electrical energy into light, has achieved remarkable results in fields such as lighting devices and displays, greatly enriching people's visual experience. However, traditional EL materials, constrained by the rigid silicon substrate, have struggled to meet the growing demand for flexible electronic materials as electronic devices become more flexible. Intrinsically stretchable AC EL materials, capable of operating under strain conditions such as stretching, twisting, and bending, offer unique applications in wearable electronic displays, flexible lighting, luminous clothing, and strain sensors.
[0003] High-performance stretchable AC electroluminescent devices should have high luminous brightness, low operating voltage and high stretchability, but taking all these performance requirements into account is a major challenge. The contradiction between high optoelectronic performance and high stretchability is difficult to balance. Although AC electroluminescent materials based on composite polymer elastomers and ELP luminescent particles generally have high stretchability and mechanical stability, their high luminous voltage and low brightness limit their applications. The root of this problem is that the dielectric constant of the elastomer matrix is low, which makes the effective luminous field intensity obtained by the ELP particles in the light-emitting layer low, and ELP usually requires a high electric field to excite visible light.
[0004] Although studies have attempted to improve the dielectric constant of polymers through various methods, these methods all have their own limitations. Although the introduction of polar dipoles can slightly improve the dielectric constant of polymers, high dipole moment groups such as fluorine and cyanide groups are prone to polarization hysteresis under high electric fields, resulting in increased device losses. At the same time, these fluorine-containing chemicals are also harmful to the environment and health. Although blending conductive fillers can significantly improve the dielectric constant when the concentration is close to the percolation threshold, it will also lead to a significant increase in dielectric loss and conductivity, and a significant decrease in dielectric breakdown strength. Dielectric ceramic fillers require a higher filling amount to effectively improve the dielectric constant. Filler particles with high filling amounts are prone to aggregation, sedimentation and stratification, resulting in a decrease in the quality of the composite material and an increase in heterogeneity, making it difficult to significantly improve the dielectric properties of the material. Summary of the Invention
[0005] To address the challenges of existing technologies, this study designed and prepared a thermoplastic functional elastomer containing a large number of polar blocks that has a dispersing effect on filler particles. These blocks interact with inorganic functional filler particles (including BTO ceramic particles and ELP luminescent particles) at the molecular level, achieving uniform dispersion of the filler particles without the need for any additional dispersants. This method allows for the simple preparation of high-quality, low-defect organic-inorganic composite films, significantly improving the dielectric constant. This approach may provide a new approach for developing AC electroluminescent devices with high optoelectronic performance and high stretchability.
[0006] The purpose of the present invention is achieved through the following technical solutions:
[0007] An intrinsically stretchable AC electroluminescent device has a symmetrical structure in which a light-emitting layer is sandwiched between two layers of flexible electrodes. The light-emitting layer is a composite elastomer formed by filling a multifunctional acrylate block copolymer with BTO ceramic fillers of different mass fractions as a dielectric matrix, which is blended with ELP luminescent particles in a proportional manner to form a composite slurry and then coated into a film. The flexible electrodes are thermoplastic single-walled carbon nanotubes / multifunctional acrylate block copolymers.
[0008] Specifically, the light-emitting layer and the flexible electrode are integrated by thermal lamination through heating to a viscous flow state.
[0009] Specifically, the multifunctional acrylic block copolymer contains polar segments with a mass fraction of ≥60 wt % and has a dispersing effect on alkaline metal compound BTO particles, thereby enabling the composite elastomer to have a high dielectric constant.
[0010] Specifically, the multifunctional acrylate block copolymer has a multi-component structure of poly(ABCD), wherein A is a dispersed chain segment having a functional group, and its content in the copolymer component is 0.1-4.8wt%; B is a hard block with a high glass transition temperature, and its molecular weight ranges from 1-60kg / mol; C is a polar soft block with a low glass transition temperature, and its molecular weight ranges from 8-320kg / mol, and its content in the copolymer component is 60-90wt%; D is a monomer with a high glass transition temperature, and its molecular weight ranges from 1-60kg / mol.
[0011] The present invention also discloses a method for preparing an intrinsically stretchable AC electroluminescent device, which comprises the following steps:
[0012] (1) 4 parts by mass of a multifunctional acrylate block copolymer was dissolved in 40 parts by mass of a tetrahydrofuran solution, 6 parts by mass of BTO particles and 15 parts by mass of ELP particles were added, the mixture was fully stirred and sheared and dispersed using an ultrasonic cell crusher with a power of ≥350 W to obtain a composite luminescent slurry;
[0013] (2) coating the composite luminescent slurry on the PET release film with a 150 μm scraper, drying, thermal annealing, and peeling off to obtain a composite luminescent layer film;
[0014] (3) Single-walled carbon nanotubes and sodium dodecyl thiosulfate were mixed in a mass ratio of 1:1 and added to deionized water. The mixture was sheared and dispersed in an ultrasonic cell crusher with a set power of 250 W for 15 minutes to obtain an aqueous dispersion of the electrode material. The electrode dispersion was filtered on a polyvinylidene fluoride organic filter membrane and rinsed three times with deionized water to obtain a single-walled carbon nanotube flexible electrode.
[0015] (4) dissolving 1 part by mass of the multifunctional block copolymer in 8 parts by mass of tetrahydrofuran solution and coating the solution on a PET release film with a 150 μm doctor blade, and obtaining a multifunctional acrylate block copolymer film after drying. Subsequently, the single-walled carbon nanotube flexible electrode prepared in (3) was transferred to the multifunctional acrylate block copolymer film and thermally annealed to obtain a single-walled carbon nanotube / multifunctional acrylate block copolymer intrinsically stretchable transparent electrode;
[0016] (5) The composite light-emitting layer film was sandwiched between two single-walled carbon nanotube / multifunctional acrylate block copolymer intrinsically stretchable transparent electrodes, aligned and compacted, and hot-pressed on a water platform at 85°C for 30 seconds under a pressure of 25 kPa. After the temperature dropped to room temperature, the applied pressure was removed to obtain an intrinsically stretchable AC electroluminescent device with a laminated structure.
[0017] Specifically, the total molecular weight of poly(acrylic acid-b-styrene-b-butyl acrylate-b-styrene) and poly(acrylic acid-b-styrene-b-isooctyl acrylate-b-styrene) in the multifunctional acrylate block copolymer in step (1) is in the range of 51-290 kg / mol, the mass fraction of the polar soft block is in the range of 60-90 wt%, and the mass fraction of the functional dispersed chain segment is in the range of 0.1-4.8 wt%.
[0018] Specifically, the ELP particles in step (1) are any one of Cu-doped ZnS phosphor, Mn-doped ZnS phosphor, Al-doped ZnS phosphor, and Cu-doped CdS phosphor.
[0019] Specifically, the BTO particles have a particle size of 700-1000 nm and a tetragonal crystal form.
[0020] Specifically, the BTO particles need to undergo surface hydroxylation treatment before use.
[0021] The beneficial effects of the present invention are as follows:
[0022] The copolymerization of high-mass fraction polar soft segment monomers in the poly(acrylic acid-b-styrene-b-butyl acrylate-b-styrene) proposed in the present invention increases the polar dipole moment offset in the elastomer, increasing the polarization level under an electric field and significantly improving the dielectric constant. The coordination interaction between the functional segments in the poly(acrylic acid-b-styrene-b-butyl acrylate-b-styrene) and the BTO particles forms a large organic-inorganic interface region in the composite material, further enhancing the interfacial polarization capability. Both poly(acrylic acid-b-styrene-b-butyl acrylate-b-styrene) and poly(acrylic acid-b-styrene-b-isooctyl acrylate-b-styrene) possess unique microphase-separated physical cross-linked structures and excellent thermoplasticity, creating conditions for simple thermal processing, lamination, and manufacturing. Thermoplastic bonding eliminates interlayer interfaces, significantly increasing interlayer bonding strength and significantly reducing interfacial contact resistance. The intrinsically stretchable AC electroluminescent device prepared by this method has full flexibility, high optoelectronic performance, and high mechanical stability. It can effectively balance various performance indicators to meet actual application requirements, which is conducive to the realization of industrial applications in wearable electronic displays, flexible lighting devices, electronic skin, luminous textiles and other fields. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] Figure 1 Schematic diagram of the stretchable AC electroluminescent device of the present invention.
[0024] Figure symbols: 1-conductive adhesive; 2-poly(acrylic acid-b-styrene-b-butyl acrylate-b-styrene); 3-single-walled carbon nanotube; 4-poly(acrylic acid-b-styrene-b-isooctyl acrylate-b-styrene); 5-ELP luminescent particles; 6-BTO ceramic filler particles. DETAILED DESCRIPTION
[0025] The following are specific embodiments of the present invention, which further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.
[0026] In this embodiment, if Figure 1As shown, the composite elastomer comprises a conductive adhesive 1, poly(acrylic acid-b-styrene-b-butyl acrylate-b-styrene) 2, single-walled carbon nanotubes 3, poly(acrylic acid-b-styrene-b-isooctyl acrylate-b-styrene) 4, ELP luminescent particles 5, and BTO ceramic filler particles 6. The multifunctional block copolymers poly(acrylic acid-b-styrene-b-butyl acrylate-b-styrene) 2 and poly(acrylic acid-b-styrene-b-isooctyl acrylate-b-styrene) 4 are obtained by stepwise addition and RAFT emulsion polymerization. The multifunctional acrylic block copolymer contains ≥60 wt% polar segments and has a dispersing effect on the alkaline metal compound BTO particles, resulting in a high dielectric constant for the composite elastomer.
[0027] Example 1: Preparation of a BTO / poly(acrylic acid-b-styrene-b-butyl acrylate-b-styrene) composite electroluminescent layer.
[0028] The process involves dissolving 10 parts by mass of poly(acrylic acid-b-styrene-b-butyl acrylate-b-styrene) in 100 parts by mass of tetrahydrofuran, adding 15 parts by mass of hydroxylated BTO ceramic particles and 37.5 parts by mass of ELP luminescent particles 5 while stirring, and dispersing the mixture by ultrasonic shearing to obtain a luminescent slurry. The luminescent slurry is then applied in a nitrogen atmosphere, dried, and annealed to obtain a composite electroluminescent layer film. The molecular structure of the poly(acrylic acid-b-styrene-b-butyl acrylate-b-styrene) 2 is:
[0029]
[0030] Example 2: Preparation of single-walled carbon nanotube / poly(acrylic acid-b-styrene-b-isooctyl acrylate-b-styrene) intrinsically stretchable transparent electrode.
[0031] 1 part by mass of single-walled carbon nanotube 3, 1000 parts by mass of sodium dodecyl thiosulfate and 8333 parts by mass of water were mixed and fully ultrasonically dispersed. Take 0.08 parts by mass of the dispersion, dilute it 6000 times and filter it on an F-type polyvinylidene fluoride organic filter membrane and rinse it three times with deionized water to obtain a single-walled carbon nanotube flexible electrode. The silicone oil paper was cut into a preset luminescent pattern and attached to a poly (acrylic acid -b- styrene -b- isooctyl acrylate -b- styrene) film, and the single-walled carbon nanotube flexible electrode was oriented toward the poly (acrylic acid -b- styrene -b- isooctyl acrylate -b- styrene) film side and pressed with a pressure of 15kPa for about 15s to obtain a single-walled carbon nanotube / poly (acrylic acid -b- styrene -b- isooctyl acrylate -b- styrene) intrinsically stretchable transparent electrode.
[0032] Example 3: Preparation of a laminated stretchable AC electroluminescent device and its integration into cellulose fabric.
[0033] A sandwich structure is formed by stacking a single-walled carbon nanotube / poly(acrylic acid-b-styrene-b-isooctyl acrylate-b-styrene) intrinsically stretchable transparent electrode, a BTO / poly(acrylic acid-b-styrene-b-butyl acrylate-b-styrene)2 composite electroluminescent layer, and a single-walled carbon nanotube / poly(acrylic acid-b-styrene-b-isooctyl acrylate-b-styrene) intrinsically stretchable transparent electrode. This is then hot-pressed for 30 seconds at 25 kPa on an 85°C horizontal platform. Once the temperature drops to room temperature, the pressure is removed to produce a monolithic stacked electroluminescent device. Conductive adhesive 1 is used to connect the electrodes to an external circuit. If integration into cellulose fabric is desired, the stacked electroluminescent device is aligned with the fabric to be integrated on a heating platform and hot-pressed for 30 seconds at 25 kPa. This completes the preparation of the stacked stretchable AC electroluminescent device and its integration into cellulose fabric.
[0034] The above embodiments are used to illustrate the present invention rather than to limit the present invention. Any modifications and changes made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.
Claims
1. An intrinsically stretchable AC electroluminescent device, characterized in that: This AC electroluminescent device is a symmetrical structure formed by sandwiching a light-emitting layer between two layers of flexible electrodes; the light-emitting layer is a composite elastomer formed by filling a multifunctional acrylate block copolymer with BTO ceramic fillers of different mass fractions as a dielectric matrix, and is blended with ELP luminescent particles in proportion to form a composite slurry, which is then scraped and coated into a film; the flexible electrodes are thermoplastic single-walled carbon nanotubes / multifunctional acrylate block copolymers.
2. The AC electroluminescent device according to claim 1, characterized in that: The light-emitting layer and the flexible electrode are integrated into one by being heated to a viscous state and then thermally laminated.
3. The AC electroluminescent device according to claim 1, characterized in that: The multifunctional acrylic ester block copolymer contains polar segments with a mass fraction of ≥60wt% and has a dispersing effect on alkaline metal compound BTO particles, thereby enabling the composite elastomer to have a high dielectric constant.
4. The AC electroluminescent device according to claim 1, characterized in that: The multifunctional acrylate block copolymer has a multi-component structure of poly(ABCD), wherein A is a dispersed chain segment with a functional group, and its content in the copolymer component is 0.1-4.8wt%; B is a hard block with a high glass transition temperature, and its molecular weight ranges from 1-60kg / mol; C is a polar soft block with a low glass transition temperature, and its molecular weight ranges from 8-320kg / mol, and its content in the copolymer component is 60-90wt%; and D is a monomer with a high glass transition temperature, and its molecular weight ranges from 1-60kg / mol.
5. A method for preparing an intrinsically stretchable AC electroluminescent device according to any one of claims 1 to 4, characterized in that: The preparation method comprises the following steps: (1) 4 parts by mass of a multifunctional acrylate block copolymer was dissolved in 40 parts by mass of a tetrahydrofuran solution, 6 parts by mass of BTO particles and 15 parts by mass of ELP particles were added, the mixture was fully stirred and sheared and dispersed using an ultrasonic cell crusher with a power of ≥350 W to obtain a composite luminescent slurry; (2) coating the composite luminescent slurry on the PET release film with a 150 μm scraper, drying, thermal annealing, and peeling off to obtain a composite luminescent layer film; (3) Single-walled carbon nanotubes and sodium dodecyl thiosulfate were mixed in a mass ratio of 1:1 and added to deionized water. The mixture was sheared and dispersed in an ultrasonic cell crusher with a set power of 250 W for 15 minutes to obtain an aqueous dispersion of the electrode material. The electrode dispersion was filtered on a polyvinylidene fluoride organic filter membrane and rinsed three times with deionized water to obtain a single-walled carbon nanotube flexible electrode. (4) dissolving 1 part by mass of the multifunctional block copolymer in 8 parts by mass of tetrahydrofuran solution and coating the solution on a PET release film with a 150 μm doctor blade, and obtaining a multifunctional acrylate block copolymer film after drying. Subsequently, the single-walled carbon nanotube flexible electrode prepared in (3) was transferred to the multifunctional acrylate block copolymer film and thermally annealed to obtain a single-walled carbon nanotube / multifunctional acrylate block copolymer intrinsically stretchable transparent electrode; (5) The composite light-emitting layer film was sandwiched between two single-walled carbon nanotube / multifunctional acrylate block copolymer intrinsically stretchable transparent electrodes, aligned and compacted, and hot-pressed on a water platform at 85°C for 30 seconds under a pressure of 25 kPa. After the temperature dropped to room temperature, the applied pressure was removed to obtain an intrinsically stretchable AC electroluminescent device with a laminated structure.
6. The preparation method according to claim 5, characterized in that The total molecular weight of poly(acrylic acid-b-styrene-b-butyl acrylate-b-styrene) and poly(acrylic acid-b-styrene-b-isooctyl acrylate-b-styrene) in the multifunctional acrylate block copolymer in step (1) is in the range of 51-290 kg / mol, wherein the mass fraction of the polar soft block is 60-90 wt%, and the mass fraction of the functional dispersed segment is 0.1-4.8 wt%.
7. The preparation method according to claim 5, characterized in that The ELP particles in step (1) are any one of Cu-doped ZnS phosphor, Mn-doped ZnS phosphor, Al-doped ZnS phosphor, and Cu-doped CdS phosphor.
8. The preparation method according to claim 5, characterized in that The BTO particles have a particle size of 700-1000 nm and a crystal form of tetragonal crystals.
9. The preparation method according to claim 5, characterized in that The BTO particles need to undergo surface hydroxylation treatment before use.