A rare earth complex ink incorporating pyrazole boron Ce(III) complexes with scattering particles, its preparation and application

Abstract

This invention relates to a rare-earth complex ink incorporating pyrazole boron Ce(III) complexes with scattering particles, its preparation, and its application, belonging to the field of light-emitting displays. Introducing scattering particles into rare-earth complex inks effectively increases light scattering and prolongs the light propagation path, thereby enhancing the chance of light absorption by the rare-earth complexes, improving luminous efficiency, and also uniformly distributing excitation light, reducing brightness spots and dark areas in printed patterns, ensuring consistent visual effects. Multi-directionally scattered light can broaden the emission angle, allowing the pattern to maintain good luminous effects from different viewing angles. Furthermore, by changing the light propagation path, the scattering particles reduce the residence time of light in the rare-earth complexes, mitigating the self-absorption effect and further improving luminous efficiency.

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 scattering particles are incorporated into a pyrazole boron Ce(III) complex, its preparation and application. Background Technology

[0002] Rare earth complexes have important applications in the field of luminescence, especially in fluorescent and phosphorescent materials, LEDs, display technologies, and laser materials. The ff transitions of rare earth elements produce very narrow spectral lines, enabling them to generate high-purity red, green, and blue primary colors of light. Furthermore, the f-electron orbitals of rare earth elements are less affected by outer electron shielding, thus rare earth complexes typically possess long excited-state lifetimes. Due to their unique optical properties, they occupy an important position in the field of luminescent materials and continuously drive the development of next-generation optoelectronic devices and display technologies.

[0003] Rare earth complexes, by binding with appropriate organic ligands, can effectively improve their solubility and stability, making them suitable for ink systems, especially for inkjet printing. These materials offer great flexibility in inkjet printing applications, enabling high-resolution luminescent pattern printing on a variety of substrates. However, rare earth complexes themselves may face some challenges in inkjet printing, such as uneven distribution of rare earth complex particles in the ink, or poor droplet control during printing, leading to uneven brightness or color in the pattern, thus limiting their application in display device fabrication. 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 with scattering particles, and its application. The method is characterized by significantly improving luminous efficiency, enhancing the uniformity and stability of printed patterns, and simultaneously improving the mechanical and optical properties of the ink. This solves the technical problems in existing technologies where the rare-earth complex particles in the ink may be unevenly distributed during inkjet printing, or where poor droplet control during printing leads to uneven brightness or color in the pattern.

[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 scattering particles; [structural formula omitted] for

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

[0007] R1, R2, R3, and R4 are each independently selected from alkyl, aryl, phenyl, halogen, or halogen-substituted alkyl groups.

[0008] Preferably, the alkyl group is selected from C1-C6. 18 Alkyl groups.

[0009] 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.

[0010] 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;

[0011] The structure of CeTp3 is as follows:

[0012] The Ce(Tp) 4Me The structure of )3 is as follows:

[0013] The Ce(Tp) 4Br The structure of )3 is as follows:

[0014]

[0015] The Ce(PzTp)3 structure is as follows:

[0016]

[0017] The Ce( i The structure of PrTp3 is as follows:

[0018]

[0019] The Ce( n The structure of BuTp)3 is as follows:

[0020] The Ce(PhTp)3 structure is as follows:

[0021]

[0022] Preferably, the scattering particles are titanium dioxide (TiO2), zinc oxide (ZnO), silicon dioxide (SiO2), barium sulfate (BaSO4), or nitric oxide (ZrO). 2。

[0023] Preferably, the particle size of the scattering particles is in the range of 0.1-1 micrometer.

[0024] According to another aspect of the present invention, a method for preparing rare earth complex ink is provided, comprising the following steps:

[0025] (1) Dissolve the pyrazole boron Ce(III) complex in a solvent containing a benzene ring and chlorine;

[0026] (2) Add the polymer and scattering particles to the solution obtained in step (1); the polymer includes one or more of polystyrene, polymethyl methacrylate, polycarbonate or polyimide.

[0027] 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%.

[0028] 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 mass fraction of the scattering particles is 1 mg / ml to 10 mg / ml.

[0029] According to another aspect of the present invention, an application of rare earth complex inks for printing photoluminescent materials is provided;

[0030] Preferably, the photoluminescent material is used to fabricate a photoluminescent display device;

[0031] Preferably, the photoluminescent material is used as an anti-counterfeiting material or as a color conversion material.

[0032] Compared with the prior art, the technical solution conceived in this invention has the following advantages in introducing scattering particles into rare earth complex inks:

[0033] (1) The introduction of scattering particles in this invention can increase light scattering, extend the propagation path of light in the ink, thereby increasing the chance of rare earth complexes absorbing light energy and improving luminous efficiency. This enhancement effect is particularly crucial in applications requiring high brightness and high luminous efficiency.

[0034] (2) The presence of the scattering particles of the present invention can uniformly scatter the excitation light, reduce the brightness spots or dark areas in the printed pattern, and ensure that the visual effect of the pattern is more consistent; it can also broaden the light emission angle by scattering light in multiple directions, so that the pattern can still maintain a good light emission effect under different viewing angles.

[0035] (3) This invention reduces the residence time of light in rare earth complexes by changing the propagation path of light, thereby reducing the self-absorption effect and improving the luminescence efficiency. Attached Figure Description

[0036] Figure 1 For Ce(Tp) in Example 2 4Me )3. Schematic diagram of control for electro-inkjet printing of complex solution.

[0037] Figure 2 For Ce(Tp) 4Me )3. Inkjet printing of low-magnification fluorescence microscope patterns using complex solutions.

[0038] Figure 3 For Ce(Tp) 4Me )3. Inkjet printing of high-magnification fluorescence microscope patterns using complex solutions.

[0039] Figure 4 This is a bar chart showing the color conversion rate of the model simulated according to Example 3 as a function of the mass fraction of scattering particles.

[0040] Figure 5 The light intensity distribution diagram is shown as a function of the mass fraction of scattering particles in the model simulated according to Example 3. Detailed Implementation

[0041] 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.

[0042] 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.

[0043] The following are specific embodiments.

[0044] Example 1

[0045] The preparation method of the pyrazole boron Ce(III) complex ink in this embodiment includes the following specific preparation steps:

[0046] 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... 4BrThe 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 titanium dioxide scattering particles (particle size range 0.1–1 μm) were added to solution B. The mass fraction of polystyrene polymer was 30–250 mg / ml, and the mass fraction of titanium dioxide scattering particles 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 titanium dioxide scattering particles were uniformly dispersed. The solution was then filtered through a 50-micron nylon filter to obtain solution C. Solution C was allowed to stand for at least 120 hours to eliminate air bubbles before use.

[0047] Example 2

[0048] 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:

[0049] 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.

[0050] 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 rose pattern is relatively complete and clear overall, and when magnified, the pixel diameter is generally around 75μm.

[0051] Example 3

[0052] This embodiment performs optical simulation on the thin film generated after rare-earth inkjet printing, constructing a simulation model consisting of four parts: a backlight, a quartz glass substrate, the inkjet-printed thin film, and a receiving surface. The backlight emits light with a peak position of 340 nm and a Lambertian light distribution. The cross-section of the backlight and the thin film is a circle with a radius of 30 micrometers, and the thin film thickness is 2 micrometers. Two receiving surfaces are established on the upper and lower surfaces of the thin film to measure the number of incident ultraviolet rays, the number of emitted ultraviolet rays, and the number of emitted blue rays. By changing the weight percentage of TiO2 scattering particles in the thin film, the color conversion rate and light intensity distribution of the thin film under different conditions are obtained. The color conversion rate is calculated as the number of emitted blue rays / (number of incident ultraviolet rays - number of emitted ultraviolet rays). Figure 4 As can be seen, the color conversion efficiency of the thin film increased from 13.73% to 17.90% after incorporating 5% scattering particles. Subsequently, the color conversion efficiency continued to increase with the increase in the weight percentage of scattering particles, but the increasing trend slowed down after 10%. Figure 5 It can be seen that the more scattering particles are incorporated, the more uniform the light intensity distribution becomes.

[0053] 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 a pyrazole boron Ce(III) complex and scattering particles; said scattering particles are titanium dioxide (TiO2), zinc oxide (ZnO), silicon dioxide (SiO2), barium sulfate (BaSO4), or nitric oxide (ZrO). 2； Remember the structural formula 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.

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 particle size of the scattering particles ranges from 0.1 to 1 micrometer.

6. The method for preparing rare earth complex ink according to any one of claims 1-5, 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 scattering particles to the solution obtained in step (1); the polymer includes one or more of polystyrene, polymethyl methacrylate, polycarbonate or polyimide.

7. The preparation method according to claim 6, characterized in that, The solvent is o-dichlorobenzene, or a mixture of o-dichlorobenzene and dichlorobenzene; in the mixture, the volume percentage of dichlorobenzene is less than or equal to 30%.

8. The preparation method according to claim 6, 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 mass fraction of the scattering particles is 1 mg / ml to 10 mg / ml.

9. The application of rare earth complex inks as described in any one of claims 1-5 for printing photoluminescent materials.

10. The application as described in claim 9, characterized in that, The photoluminescent material is used to prepare photoluminescent display devices.

11. The application as described in claim 10, characterized in that, The photoluminescent material can be used as an anti-counterfeiting material or as a color conversion material.

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