A rare earth complex ink with a heat-conducting material incorporated into a pyrazole boron Ce (III) complex, preparation and application

Abstract

This invention relates to a rare-earth complex ink incorporating a pyrazole boron Ce(III) complex with a thermally conductive material, its preparation, and its application, belonging to the field of light-emitting displays. More specifically, by incorporating a thermally conductive material into the ink, heat can be effectively and rapidly conducted away, preventing non-radiative losses due to overheating of the rare-earth complex and thus improving luminous efficiency. During inkjet printing, an increase in printhead temperature may cause rare-earth complex particles in the ink to agglomerate, thereby affecting print uniformity and pattern quality. The addition of a thermally conductive material helps stabilize the ink temperature, reduces particle thermal movement, prevents agglomeration and sedimentation, improves printing stability and reliability, and ensures long-term printhead operation.

Description

Technical Field

[0001] This invention belongs to the field of light-emitting display, and more specifically, relates to a rare earth complex ink in which a thermally conductive material is incorporated into a pyrazole boron Ce(III) complex, its preparation and application. Background Technology

[0002] Rare earth elements possess unique narrow-bandgap luminescence properties, enabling the generation of precise emission wavelengths through electronic transitions. Rare earth complexes, as luminescent materials, exhibit high luminescent efficiency, particularly demonstrating excellent performance in the red, green, and blue light regions. This provides highly efficient luminescent materials for display technology and light source development. Rare earth complexes typically exhibit long luminescent lifetimes, and their luminescence process is less affected by external environmental factors, possessing good thermal and light stability. This characteristic allows rare earth complexes to maintain highly efficient and stable luminescent performance even under prolonged operation and harsh environments. Advances in rare earth complex synthesis technology and the continuous emergence of new luminescent materials are driving innovation in display technology, lighting technology, anti-counterfeiting technology, optical sensing, and catalysis.

[0003] Inkjet printing technology using rare earth complexes as inks is gradually becoming an important method in modern materials manufacturing due to its precision, flexibility, and efficiency, particularly in anti-counterfeiting technology, display manufacturing, and optical devices. Since rare earth complexes typically exist in inks in particulate or nanoparticle form, increased temperature can lead to particle aggregation and precipitation, even affecting the optical properties of the rare earth complexes. Therefore, thermal management of the ink is a critical issue in rare earth complex inkjet printing applications. Furthermore, in practical applications, the luminescence process of rare earth complexes is highly sensitive to temperature, especially in devices with high-power excitation or long-term operation, where thermal effects can lead to reduced luminous efficiency and accelerated light attenuation. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing rare earth complex inks incorporating pyrazole boron Ce(III) complexes into thermally conductive materials and their applications. The method effectively solves the thermal management problem in inkjet printing, ensuring the luminescence efficiency of the rare earth complexes, the accuracy of the printed pattern, and the stability of the ink. The thermally conductive material optimizes the heat conduction path, avoiding localized overheating and reducing the decrease in photoluminescence efficiency and particle agglomeration of the rare earth complexes.

[0005] According to a first aspect of the present invention, a rare earth complex ink is provided, comprising a pyrazole boron Ce(III) complex and a thermally conductive material; [structural formula omitted] for

[0006] The structural formula of the pyrazole boron Ce(III) complex is:

[0007]

[0008] R1, R2, R3, and R4 are each independently selected from alkyl, aryl, phenyl, halogen, or halogen-substituted alkyl groups.

[0009] Preferably, the alkyl group is selected from C1-C6. 18 Alkyl groups.

[0010] Preferably, R1 is -CH3; R2 is selected from Cl-C 18 Alkyl or halogen; R3 is -CH3; R4 is selected from C1-C 18 Alkyl or halogen.

[0011] Preferably, the pyrazole boron Ce(III) complex is CeTp3 or Ce(Tp 4Me 3. Ce(Tp) 4Br )3、Ce(PzTp)3、Ce( i PrTp)3、Ce( n At least one of BuTp)3 and Ce(PhTp)3;

[0012] The structure of CeTp3 is as follows:

[0013]

[0014] The Ce(Tp) 4Me The structure of )3 is as follows:

[0015] The Ce(Tp) 4Br The structure of )3 is as follows:

[0016]

[0017] The Ce(PzTp)3 structure is as follows:

[0018]

[0019] The Ce( i The structure of PrTp3 is as follows:

[0020]

[0021] The Ce( n The structure of BuTp)3 is as follows:

[0022] The Ce(PhTp)3 structure is as follows:

[0023]

[0024] Preferably, the thermal conductivity of the thermally conductive material is greater than 40 W / (m·K);

[0025] Preferably, the particle size of the thermally conductive material is between 0.1 and 1 micrometer.

[0026] Preferably, the thermally conductive material is boron nitride nanosheets or alumina nanoparticles.

[0027] According to another aspect of the present invention, a method for preparing rare earth complex ink is provided, comprising the following steps:

[0028] (1) Dissolve the pyrazole boron Ce(III) complex in a solvent containing a benzene ring and chlorine;

[0029] (2) Add the polymer and thermally conductive material to the solution obtained in step (1); the polymer includes one or more of polystyrene, polymethyl methacrylate, polycarbonate or polyimide.

[0030] Preferably, the solvent is o-dichlorobenzene, or a mixture of o-dichlorobenzene and dichlorobenzene; preferably, the volume percentage of dichlorobenzene in the mixture is less than or equal to 30%.

[0031] Preferably, in step (1), the concentration of the pyrazole boron Ce(III) complex in the solvent is 1 mg / ml to 10 mg / ml; in step (2), the concentration of the polymer in the solution is 30 mg / ml to 250 mg / ml, and the concentration of the thermally conductive material is 1 mg / ml to 10 mg / ml.

[0032] According to another aspect of the present invention, an application of rare earth complex inks for printing photoluminescent materials is provided;

[0033] Preferably, the photoluminescent material is used to fabricate a photoluminescent display device;

[0034] Preferably, the photoluminescent material is used as an anti-counterfeiting material or as a color conversion material.

[0035] In summary, compared with the prior art, the above-described technical solutions conceived by this invention mainly possess the following technical advantages:

[0036] (1) By incorporating thermally conductive materials into the ink, the present invention can effectively and rapidly transfer heat away, avoiding non-radiative losses of rare earth complexes due to overheating, thereby improving luminous efficiency. This thermal management is particularly important for high-intensity excitation applications. In high-power LED, OLED displays and other scenarios, the thermal management of rare earth luminescent materials is a key factor determining their luminous efficiency and lifespan.

[0037] (2) During inkjet printing, the increased temperature of the printhead may cause rare earth complex particles in the ink to agglomerate, thus affecting print uniformity and pattern quality. Agglomerated particles not only affect the flowability of the inkjet process but may also clog the print nozzles, leading to print failure. The introduction of thermally conductive materials can help stabilize the ink temperature, reduce the thermal movement of rare earth complex particles, and prevent their agglomeration and precipitation. At the same time, the presence of thermally conductive materials can also increase the stability of the ink and ensure the reliability of the printhead during long-term operation. Attached Figure Description

[0038] Figure 1 For Ce(Tp) in Example 2 4Me )3. Schematic diagram of control for electro-inkjet printing of complex solution.

[0039] Figure 2 For Ce(Tp) 4Me )3. Inkjet printing of low-magnification fluorescence microscope patterns using complex solutions.

[0040] Figure 3 For Ce(Tp) 4Me )3. Inkjet printing of high-magnification fluorescence microscope patterns using complex solutions.

[0041] Figure 4 The nanoparticles were undoped alumina nanoparticles and those doped with Ce(Tp) at weight percentages of 3%, 6%, and 9%, respectively. 4Me )3. Temperature change curve of the spin-coated film of complex ink on a 100℃ hot plate from room temperature to steady state over time.

[0042] Figure 5 The nanoparticles were undoped alumina nanoparticles and those doped with Ce(Tp) at weight percentages of 3%, 6%, and 9%, respectively. 4Me )3 The temperature change curve of the spin-coated film of the complex ink on a 125℃ hot plate from room temperature to steady state over time.

[0043] Figure 6 The nanoparticles were undoped alumina nanoparticles and those doped with Ce(Tp) at weight percentages of 3%, 6%, and 9%, respectively. 4Me )3 The temperature change curve of the spin-coated film of the complex ink on a 145℃ hot plate from room temperature to steady state over time. Detailed Implementation

[0044] 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. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0045] The rare earth complex ink of this invention is used for printing photoluminescent materials. The specific printing parameters are as follows: the base voltage of inkjet printing is 800-1200V, the pulse voltage is 800-1500V, the frequency is 20-50Hz, the duty cycle is 50%-90%, the delay time is 30-60ms, and the substrate moving speed is 10-20 mm / min.

[0046] The following are specific embodiments.

[0047] Example 1

[0048] The preparation method of the pyrazole boron Ce(III) complex ink in this embodiment includes the following specific preparation steps:

[0049] This process must be carried out entirely in the absence of water and oxygen, at a temperature of 20–30°C. First, Ce(Tp) needs to be... 4Br The complex (solute A) is dissolved in o-dichlorobenzene or a mixed solvent of o-dichlorobenzene and dichlorobenzene (solvent A) to form a mixed solution (solution A). The volume ratio of dichlorobenzene in the mixed solvent is less than or equal to 30%, and the mass / volume ratio of solute to solvent is 1–10 mg / ml. Solution A is mixed using a homogenizer for 2–3 hours at a speed of 2000–3000 rpm until the solute is dissolved. Solution A is then filtered through a 0.22-micron nylon filter to obtain solution B. Polystyrene polymer (weight-average molecular weight Mw = 30,000–80,000) and alumina nanoparticles (particle size range 0.1–10 μm) were added to solution B. The mass fraction of polystyrene polymer was 30–250 mg / ml, and the mass fraction of alumina nanoparticles was 1–10 mg / ml. The mixture was stirred in a homogenizer for 72–96 hours at a speed of 2000–3000 rpm until the polymer was dissolved and the alumina nanoparticles were uniformly dispersed. The solution was then filtered through a 50 μm nylon filter to obtain solution C. Solution C was allowed to stand for at least 120 hours to eliminate air bubbles before use.

[0050] Example 2

[0051] The inkjet printing application method in this embodiment, the inkjet printing process is as follows: Figure 1 As shown, the specific application steps are as follows:

[0052] a) The inkjet printing process takes place entirely in an air environment. The substrate is made of quartz glass. The substrate is cleaned with deionized water for 5-20 minutes, acetone for 15-20 minutes, isopropanol for 15-20 minutes, deionized water for 15-20 minutes, and then dried with a nitrogen gun.

[0053] b) Place the cleaned quartz glass into the designated position on the inkjet printer. Slowly add solution C along the tube wall into the needle of the electrohydraulic inkjet printer. Set the base voltage to 800–1200V, pulse voltage to 800–1500V, frequency to 20–50Hz, duty cycle to 50%–90%, delay time to 30–60ms, and printing speed to 10–20mm / s. The final printing result is as follows. Figure 2 and Figure 3 As shown, the printed Great Wall pattern is relatively complete and clear, with the pixel diameter around 90μm when magnified.

[0054] Example 3

[0055] Pyrazole boron Ce(III) complex inks incorporating different mass fractions of alumina nanoparticles were spin-coated onto quartz glass, and different temperatures were set to test the heat dissipation performance of pyrazole boron Ce(III) complex films with different mass fractions. Figure 4 , Figure 5 and Figure 6 The results show that after incorporating alumina nanoparticles into the film, the steady-state temperature of the film decreased by more than 7°C compared to that without alumina nanoparticles, indicating that the alumina nanoparticles construct a thermally conductive system in the film, enabling the temperature to diffuse to the surface more rapidly. However, as the proportion of alumina nanoparticles increases, the downward trend in the steady-state temperature gradually flattens out.

[0056] Those skilled in the art will readily understand that the above description is merely 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 scope of protection of the present invention.

Claims

1. A rare earth complex ink, characterized in that, Contains pyrazole boron Ce(III) complex and thermally conductive material; [Structure formula notation] for ; The structural formula of the pyrazole boron Ce(III) complex is: ; R1, R2, R3, and R4 are each independently selected from alkyl, aryl, phenyl, halogen, or halogen-substituted alkyl groups; The thermally conductive material is boron nitride nanosheets or alumina nanoparticles.

2. The rare earth complex ink as described in claim 1, characterized in that, The alkyl group is selected from C1-C6. 18 Alkyl groups.

3. The rare earth complex ink as described in claim 1, characterized in that, R1 is -CH3; R2 is selected from C1-C 18 Alkyl or halogen; R3 is -CH3; R4 is selected from C1-C 18 Alkyl or halogen.

4. The rare earth complex ink as described in claim 1, characterized in that, The pyrazole boron Ce(III) complex is CeTp3, Ce(Tp 4Me 3. Ce(Tp) 4Br )3、Ce(PzTp)3、Ce( i PrTp)3、Ce( n At least one of BuTp)3 and Ce(PhTp)3; The structure of CeTp3 is as follows: ； The Ce(Tp) 4Me The structure of )3 is as follows: ； The Ce(Tp) 4Br The structure of )3 is as follows: ； The Ce(PzTp)3 structure is as follows: ； The Ce( i The structure of PrTp3 is as follows: ； The Ce( n The structure of BuTp)3 is as follows: ； The Ce(PhTp)3 structure is as follows: or 。 5. The rare earth complex ink as described in claim 1, characterized in that, The thermal conductivity of the thermally conductive material is greater than 40 W / (m·K).

6. The rare earth complex ink as described in claim 1, characterized in that, The particle size of the thermally conductive material is between 0.1 and 1 micrometer.

7. The method for preparing rare earth complex ink according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Dissolve the pyrazole boron Ce(III) complex in a solvent containing a benzene ring and chlorine; (2) Add the polymer and thermally conductive material to the solution obtained in step (1); the polymer includes one or more of polystyrene, polymethyl methacrylate, polycarbonate or polyimide.

8. The preparation method according to claim 7, characterized in that, The solvent is o-dichlorobenzene, or a mixture of o-dichlorobenzene and dichlorobenzene.

9. The preparation method according to claim 8, characterized in that, In the mixed solvent, the volume percentage of dichlorobenzene is less than or equal to 30%.

10. The preparation method according to claim 7, characterized in that, In step (1), the concentration of the pyrazole boron Ce(III) complex in the solvent is 1 mg / ml to 10 mg / ml; in step (2), the concentration of the polymer in the solution is 30 mg / ml to 250 mg / ml, and the concentration of the thermally conductive material is 1 mg / ml to 10 mg / ml.

11. The application of rare earth complex inks as described in any one of claims 1-6 for printing photoluminescent materials.

12. The application as described in claim 11, characterized in that, The photoluminescent material is used to prepare photoluminescent display devices.

13. The application as described in claim 11, characterized in that, The photoluminescent material can be used as an anti-counterfeiting material or as a color conversion material.

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