Reflector plate printing quantum dot ink and preparation method thereof

Abstract

The invention belongs to the technical field of photoelectric materials. The invention relates to a quantum dot ink, in particular to a reflector plate printing quantum dot ink and a preparation method thereof. The product comprises composite quantum dots and basic ink, wherein the composite quantum dots comprise flaky nano zinc oxide and sphere-like nano zinc oxide; the dosage of the sphere-like nano-zinc oxide is 30-40% of the mass of the flaky nano-zinc oxide; the D50 of the sphere-like nano zinc oxide is 1 to 2 nm; the degree of sphericity of the sphere-like nano zinc oxide is 8.5 to 9.5; the D50 of the flaky nano zinc oxide ranges from 10 nm to 15 nm; the basic ink comprises a solvent, a resin adhesive accounting for 15-20% of the mass of the solvent and an anionic surfactant accounting for 4-6% of the mass of the solvent; the mass ratio of the basic ink to the composite quantum dots is (18-20): 1. The composite quantum dot further comprises a coating layer on the surface, and the coating layer is polymethyl methacrylate.

Description

Technical Field

[0001] The present invention belongs to the technical field of optoelectronic materials, and more specifically, relates to a reflector printed quantum dot ink and a preparation method thereof. Background Art

[0002] Reflector printing QD ink is a special ink technology that involves using quantum dots (QD) as luminescent materials and applying them to reflectors through inkjet printing technology. Quantum dots are semiconductor nanocrystals with unique optoelectronic properties that can emit light of a specific wavelength when excited by light. This ink technology has broad application prospects in the field of optoelectronic devices, for example, in quantum dot TVs, LED lighting, optoelectronic sensors and other products.

[0003] In practical applications, for example, in the method of printing ink dots on a reflective sheet, it is first necessary to mix the proportions of gray, black, and white inks according to design requirements to form a blended ink, and then use a screen to print the blended ink on the reflective sheet and solidify it.

[0004] At present, in order to obtain better quantum dot ink products, the photoelectric performance of the product can be improved by increasing the content of quantum dots in the ink. However, since the size of quantum dots is at the nanometer level, their surface free energy is high and they are prone to agglomeration, especially after increasing the dosage, the agglomeration problem becomes more prominent. Summary of the invention

[0005] The technical problem to be solved by the present invention is that in the actual use of conventional reflector printed quantum dot ink, in order to obtain more excellent photoelectric performance, excessive addition of quantum dots leads to their agglomeration, which affects the stability and uniformity of product performance. Based on the above problem, the present invention provides a method for preparing reflector printed quantum dot ink.

[0006] The purpose of the present invention is to provide a reflective sheet printed with quantum dot ink.

[0007] Another object of the present invention is to provide a method for preparing quantum dot ink for printing on a reflective sheet.

[0008] The above-mentioned purpose of the present invention is achieved through the following technical solutions:

[0009] A reflective sheet printing quantum dot ink, comprising composite quantum dots and basic ink;

[0010] Wherein, the composite quantum dots include flake-shaped nano zinc oxide and spherical nano zinc oxide;

[0011] The amount of the spherical nano zinc oxide is 30-40% of the mass of the flaky nano zinc oxide;

[0012] The D50 of the quasi-spherical nano zinc oxide is 1-2 nm; the sphericity of the quasi-spherical nano zinc oxide is 8.5-9.5;

[0013] The D50 of the flaky nano zinc oxide is 10-15 nm;

[0014] The base ink comprises a solvent, a resin binder of 15-20% by weight of the solvent, and an anionic surfactant of 4-6% by weight of the solvent;

[0015] The mass ratio of the basic ink to the composite quantum dots is 18-20:1.

[0016] Beneficial effects of the above technical solution:

[0017] For the quantum dot ink system, two nano zinc oxides with different morphologies are used for matching, especially, different sizes are strictly selected for matching. Specifically, the particle size of the flaky nano zinc oxide is larger than that of the spherical nano zinc oxide, and its dosage is relatively more. The main reason for this setting is:

[0018] Usually, in order to obtain relatively excellent photoelectric performance, it is considered to increase the concentration of quantum dots in the ink. However, for nanoparticles, the increase in concentration can easily lead to a large amount of agglomeration in the ink system, thereby significantly affecting the photoelectric performance of the product, especially its uniformity. The inventors found that by compounding flaky nano zinc oxide with relatively large particle size and spherical nano zinc oxide with relatively small particle size, the technical problem can be well solved. This is because the presence of large-particle flaky nano zinc oxide can easily form a photoelectric sensing layer of continuous sheets after the ink is solidified, and the gaps existing in the process of flaky nano zinc oxide stacking can be filled by small-particle spherical nano zinc oxide. Since the flaky nano zinc oxide with larger particles is easy to form larger gaps between each other during the process of stacking, at this time, both in the surface direction and in the thickness direction, the gaps are similar. After the gaps are stacked together and the base ink is solidified, a stable physical structure is formed. In particular, after the small-particle spherical nano zinc oxide is filled, the physical structure is further reinforced. Therefore, the photoelectric performance and stability of the product are reliable.

[0019] In addition, due to the mutual accumulation of large particles of flaky zinc oxide, the overall amount of quantum dots used is reduced. This is because when large particles are accumulated, the stacking density is relatively lower than that between small particles, which means that the demand for the total amount of quantum dots can be reduced. In addition, by filling the internal spherical shape, the skeleton is realized by relying on the flaky shape of large particles. In this way, the demand for the overall quantum dots can be reduced while maintaining a complete photoelectric reaction network, thereby reducing the probability of large-scale agglomeration.

[0020] Furthermore, the composite quantum dot also includes a coating layer on the surface, and the coating layer is polymethyl methacrylate.

[0021] Furthermore, the polymethyl methacrylate is coated on the surface of the flaky nano zinc oxide in an island shape; and the polymethyl methacrylate is completely coated on the surface of the spherical nano zinc oxide.

[0022] Beneficial effects of the above technical solution:

[0023] The inventors found that during the processing of the product, it is necessary to use stirring or shearing force to achieve uniform dispersion of flaky nano zinc oxide and spherical nano zinc oxide. However, during the processing, the physical friction between particles may cause changes in their surface defect structure. In addition, during the use of the product, the interference of oxygen and moisture in the air may also affect the stability of the photoelectric performance of the product. The above problems can be solved by coating with polymethyl methacrylate.

[0024] However, a new problem is that when the flaky nano zinc oxide is completely coated with polymethyl methacrylate, it tends to settle quickly in the ink system, thereby affecting the stable and uniform dispersion of the quantum dots in the ink system, which makes the photoelectric performance of the product more likely to decline. By only partially coating its surface, that is, coating in an island shape, adjacent islands are separated. In this way, during the dispersion process with the ink, the stretched polymer chains of the binder in the ink can be entangled with its island structure to undergo physical effects such as entanglement, thereby assisting its stable dispersion under the restraining effect of the binder and reducing the possibility of sedimentation. The spherical nano zinc oxide can be stably deposited in the gap with the help of the physical limiting effect of the flaky nano zinc oxide.

[0025] Furthermore, a silane coupling agent is included between the composite quantum dots and the coating layer; the silane coupling agent is selected from any one of silane coupling agent KH-540, silane coupling agent KH-550, silane coupling agent KH-560, silane coupling agent KH-570, and silane coupling agent KH-580.

[0026] Furthermore, the solvent includes cyclohexane, n-tridecane and n-nonane; wherein the mass ratio of the three is cyclohexane:n-tridecane:n-nonane=0.8-0.9:1.9-2.1:4.2-4.4.

[0027] Furthermore, the resin adhesive is a mixture of bisphenol A epoxy resin, terpene resin and C5 petroleum resin in a mass ratio of 2.0-2.2:0.5-0.6:0.2-0.3.

[0028] Furthermore, the anionic surfactant is selected from any one of sodium dodecylbenzene sulfonate, sodium stearate, sodium fatty alcohol polyoxyethylene ether sulfate, and sodium dodecyl sulfate.

[0029] A method for preparing a reflective sheet printed quantum dot ink, the specific preparation steps comprising:

[0030] Preparation of composite quantum dots:

[0031] Ultrasonic dispersion of flaky nano zinc oxide and spherical nano zinc oxide in water to obtain a dispersion; the ultrasonic frequency is 200-250kHz, and the ultrasonic time is 1.5-2.5h;

[0032] The dispersion was filtered and then freeze-dried in vacuum to obtain composite quantum dots;

[0033] Ink preparation:

[0034] The solvent is divided into two equal parts, one of the solvents is first stirred and mixed with the resin binder, and then the composite quantum dots are added. After shearing and dispersing evenly, the other solvent and anionic surfactant are added. After further shearing and dispersing evenly, the material is discharged to obtain the reflective sheet printing quantum dot ink.

[0035] Furthermore, the specific preparation steps also include:

[0036] Dissolving polymethyl methacrylate in solvent A to obtain a polymethyl methacrylate solution with a mass fraction of 6-8%;

[0037] The flaky nano zinc oxide and solvent A are mixed in a mass ratio of 1:10 and then dispersed by ultrasonication to obtain a flaky nano zinc oxide dispersion;

[0038] The spherical nano zinc oxide and solvent A are mixed in a mass ratio of 1:8 and then dispersed by ultrasonication to obtain a spherical nano zinc oxide dispersion;

[0039] After mixing the flaky nano zinc oxide dispersion and the polymethyl methacrylate solution at a mass ratio of 1:1.2-1.5, spray drying is performed under the conditions of an inlet air temperature of 140°C, an outlet air temperature of 120°C, a feed rate of 50g / min, and a main disk speed of 8000r / min to obtain pretreated flaky nano zinc oxide;

[0040] By adjusting the amount of polymethyl methacrylate relative to the flaky nano zinc oxide and using a spray drying process, the polymethyl methacrylate is coated on the surface of the flaky nano zinc oxide in an island shape;

[0041] The spherical nano zinc oxide dispersion and the polymethyl methacrylate solution are mixed at a mass ratio of 1:2.0-2.5, and spray-dried at an inlet air temperature of 130°C, an outlet air temperature of 110°C, a feed rate of 50g / min, and a main disk speed of 8000r / min to obtain pretreated spherical nano zinc oxide;

[0042] By adjusting the amount of polymethyl methacrylate relative to the spherical nano zinc oxide, and using a spray drying process, the polymethyl methacrylate is completely coated on the surface of the spherical nano zinc oxide;

[0043] Ultrasonic dispersion of the pretreated flaky nano zinc oxide and the pretreated spherical nano zinc oxide in water to obtain a dispersion; the ultrasonic frequency is 200-250 kHz, and the ultrasonic time is 1.5-2.5 h;

[0044] Wherein, the amount of the pre-treated spherical nano zinc oxide is 30-40% of the mass of the pre-treated flaky nano zinc oxide;

[0045] The dispersion was filtered and then freeze-dried in vacuum to obtain composite quantum dots;

[0046] Wherein, the solvent A is selected from any one of acetone, dimethylformamide, dichloroethane, tetrahydrofuran and ethyl acetate.

[0047] Furthermore, the specific preparation steps also include:

[0048] The flaky nano zinc oxide and solvent A are mixed in a mass ratio of 1:10, and then ultrasonically dispersed, and a silane coupling agent is added in an amount of 3-5% by mass of the flaky nano zinc oxide to obtain a flaky nano zinc oxide dispersion;

[0049] The spherical nano zinc oxide and solvent A are mixed in a mass ratio of 1:8, dispersed by ultrasonication, and a silane coupling agent of 3-5% of the mass of the spherical nano zinc oxide is added to obtain a spherical nano zinc oxide dispersion. DETAILED DESCRIPTION

[0050] The present invention is further described below with reference to specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0051] Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0052] Example 1

[0053] Preparation of composite quantum dots:

[0054] After mixing flaky nano zinc oxide and solvent A at a mass ratio of 1:10, ultrasonically disperse the mixture at an ultrasonic frequency of 160 kHz for 30 minutes, add a silane coupling agent of 3% by mass of the flaky nano zinc oxide, and then heat and stir the mixture at a temperature of 50° C. and a stirring speed of 200 r / min for 10 minutes to obtain a flaky nano zinc oxide dispersion;

[0055] The D50 of the flaky nano zinc oxide is 10 nm;

[0056] Spherical nano zinc oxide and solvent A are mixed at a mass ratio of 1:8, and ultrasonically dispersed for 30 minutes at an ultrasonic frequency of 160 kHz, and then a silane coupling agent of 3% by mass of the spherical nano zinc oxide is added, and then heated and stirred for 10 minutes at a temperature of 50° C. and a stirring speed of 200 r / min to obtain a spherical nano zinc oxide dispersion;

[0057] The D50 of the quasi-spherical nano zinc oxide is 1 nm; the sphericity of the quasi-spherical nano zinc oxide is 8.5;

[0058] The silane coupling agent is selected from silane coupling agent KH-540;

[0059] Dissolving polymethyl methacrylate in solvent A to obtain a polymethyl methacrylate solution with a mass fraction of 6%;

[0060] After mixing the flaky nano zinc oxide dispersion and the polymethyl methacrylate solution at a mass ratio of 1:1.2, spray drying was performed under the conditions of an inlet air temperature of 140°C, an outlet air temperature of 120°C, a feed rate of 50g / min, and a main disk speed of 8000r / min to obtain pretreated flaky nano zinc oxide;

[0061] The spherical nano zinc oxide dispersion and the polymethyl methacrylate solution were mixed at a mass ratio of 1:2.0, and then spray-dried at an inlet air temperature of 130°C, an outlet air temperature of 110°C, a feed rate of 50g / min, and a main disk speed of 8000r / min to obtain pretreated spherical nano zinc oxide.

[0062] The pretreated flaky nano zinc oxide and the pretreated spherical nano zinc oxide are ultrasonically dispersed in water to obtain a dispersion; the ultrasonic frequency is 200 kHz, and the ultrasonic time is 1.5 h;

[0063] The dispersion was filtered and then freeze-dried in vacuum to obtain composite quantum dots;

[0064] Wherein, the solvent A is selected from acetone;

[0065] Ink preparation:

[0066] Prepare the raw materials according to the following ratio, weigh: solvent, resin binder with 15% of the solvent mass, and anionic surfactant with 4% of the solvent mass; take the solvent, resin binder and anionic surfactant as the base ink, and the total mass of the three as the mass of the base ink, and prepare the raw materials according to the mass ratio of the base ink to the composite quantum dots of 18:1;

[0067] The solvent was divided into two equal parts, one of the solvents was mixed with the resin binder, and then the mixture was stirred for 2 hours at a temperature of 80°C and a stirring speed of 220 r / min, and then the composite quantum dots were added, and the mixture was sheared and dispersed for 30 minutes at a shear rate of 4000 r / min, and then the other solvent and anionic surfactant were added, and the mixture was sheared and dispersed for 20 minutes, and then the material was discharged to obtain the reflector printing quantum dot ink;

[0068] The solvent includes cyclohexane, n-tridecane and n-nonane; wherein the mass ratio of the three is cyclohexane: n-tridecane: n-nonane=0.8:1.9:4.2;

[0069] The resin adhesive is prepared by mixing bisphenol A epoxy resin, terpene resin and C5 petroleum resin in a mass ratio of 2.0:0.5:0.2;

[0070] The anionic surfactant is selected from sodium dodecylbenzene sulfonate.

[0071] Example 2

[0072] Preparation of composite quantum dots:

[0073] After mixing the flaky nano zinc oxide and solvent A at a mass ratio of 1:10, ultrasonically disperse the mixture at an ultrasonic frequency of 170 kHz for 40 minutes, add a silane coupling agent of 4% by mass of the flaky nano zinc oxide, and then heat and stir the mixture at a temperature of 55° C. and a stirring speed of 200 r / min for 12 minutes to obtain a flaky nano zinc oxide dispersion;

[0074] The D50 of the flaky nano zinc oxide is 12 nm;

[0075] The spherical nano zinc oxide and solvent A are mixed at a mass ratio of 1:8, and ultrasonically dispersed for 40 minutes at an ultrasonic frequency of 170 kHz, and then a silane coupling agent of 4% by mass of the spherical nano zinc oxide is added, and then heated and stirred for 12 minutes at a temperature of 55° C. and a stirring speed of 200 r / min to obtain a spherical nano zinc oxide dispersion;

[0076] The D50 of the quasi-spherical nano zinc oxide is 1.5 nm; the sphericity of the quasi-spherical nano zinc oxide is 8.8;

[0077] The silane coupling agent is selected from silane coupling agent KH-550;

[0078] Dissolving polymethyl methacrylate in solvent A to obtain a polymethyl methacrylate solution with a mass fraction of 7%;

[0079] After mixing the flaky nano zinc oxide dispersion and the polymethyl methacrylate solution at a mass ratio of 1:1.3, spray drying was performed under the conditions of an inlet air temperature of 140°C, an outlet air temperature of 120°C, a feed rate of 50g / min, and a main disk speed of 8000r / min to obtain pretreated flaky nano zinc oxide;

[0080] The spherical nano zinc oxide dispersion and the polymethyl methacrylate solution were mixed at a mass ratio of 1:2.3, and then spray-dried at an inlet air temperature of 130°C, an outlet air temperature of 110°C, a feed rate of 50g / min, and a main disk speed of 8000r / min to obtain pretreated spherical nano zinc oxide.

[0081] The pretreated flaky nano zinc oxide and the pretreated spherical nano zinc oxide are ultrasonically dispersed in water to obtain a dispersion; the ultrasonic frequency is 230 kHz, and the ultrasonic time is 1.8 h;

[0082] The dispersion was filtered and then freeze-dried in vacuum to obtain composite quantum dots;

[0083] Wherein, the solvent A is selected from dimethylformamide;

[0084] Ink preparation:

[0085] Prepare the raw materials according to the following ratio, weigh: solvent, resin binder with 18% of the solvent mass, and anionic surfactant with 5% of the solvent mass; take the solvent, resin binder and anionic surfactant as the base ink, and the total mass of the three as the mass of the base ink, and prepare the raw materials according to the mass ratio of the base ink to the composite quantum dots of 19:1;

[0086] The solvent was divided into two equal parts, one of the solvents was mixed with the resin binder, and then the mixture was stirred for 2 hours at a temperature of 80°C and a stirring speed of 220 r / min, and then the composite quantum dots were added, and the mixture was sheared and dispersed for 30 minutes at a shear rate of 4000 r / min, and then the other solvent and anionic surfactant were added, and the mixture was sheared and dispersed for 20 minutes, and then the material was discharged to obtain the reflector printing quantum dot ink;

[0087] The solvent includes cyclohexane, n-tridecane and n-nonane; wherein the mass ratio of the three is cyclohexane: n-tridecane: n-nonane=0.86:2:4.3;

[0088] The resin adhesive is prepared by mixing bisphenol A epoxy resin, terpene resin and C5 petroleum resin in a mass ratio of 2.1:0.5:0.2;

[0089] The anionic surfactant is selected from sodium stearate.

[0090] Example 3

[0091] Preparation of composite quantum dots:

[0092] After mixing flaky nano zinc oxide and solvent A at a mass ratio of 1:10, ultrasonically disperse the mixture at an ultrasonic frequency of 180 kHz for 60 minutes, add a silane coupling agent of 5% by mass of the flaky nano zinc oxide, and then heat and stir the mixture at a temperature of 60° C. and a stirring speed of 200 r / min for 15 minutes to obtain a flaky nano zinc oxide dispersion;

[0093] The D50 of the flaky nano zinc oxide is 15 nm;

[0094] Spherical nano zinc oxide and solvent A are mixed at a mass ratio of 1:8, and ultrasonically dispersed for 60 minutes at an ultrasonic frequency of 180 kHz, and then a silane coupling agent of 5% by mass of the spherical nano zinc oxide is added, and then heated and stirred for 15 minutes at a temperature of 60° C. and a stirring speed of 200 r / min to obtain a spherical nano zinc oxide dispersion;

[0095] The D50 of the quasi-spherical nano zinc oxide is 2 nm; the sphericity of the quasi-spherical nano zinc oxide is 9.5;

[0096] The silane coupling agent is selected from silane coupling agent KH-560;

[0097] Dissolving polymethyl methacrylate in solvent A to obtain a polymethyl methacrylate solution with a mass fraction of 8%;

[0098] After mixing the flaky nano zinc oxide dispersion and the polymethyl methacrylate solution at a mass ratio of 1:1.5, spray drying was performed under the conditions of an inlet air temperature of 140°C, an outlet air temperature of 120°C, a feed rate of 50g / min, and a main disk speed of 8000r / min to obtain pretreated flaky nano zinc oxide;

[0099] The spherical nano zinc oxide dispersion and the polymethyl methacrylate solution were mixed at a mass ratio of 1:2.5, and then spray-dried at an inlet air temperature of 130°C, an outlet air temperature of 110°C, a feed rate of 50g / min, and a main disk speed of 8000r / min to obtain pretreated spherical nano zinc oxide.

[0100] The pretreated flaky nano zinc oxide and the pretreated spherical nano zinc oxide were ultrasonically dispersed in water to obtain a dispersion; the ultrasonic frequency was 250 kHz, and the ultrasonic time was 2.5 h;

[0101] The dispersion was filtered and then freeze-dried in vacuum to obtain composite quantum dots;

[0102] Wherein, the solvent A is selected from tetrahydrofuran;

[0103] Ink preparation:

[0104] Prepare the raw materials according to the following ratio, weigh: solvent, resin binder with 20% of the solvent mass, and anionic surfactant with 6% of the solvent mass; take the solvent, resin binder and anionic surfactant as the base ink, and the total mass of the three as the mass of the base ink, and prepare the raw materials according to the mass ratio of the base ink to the composite quantum dots of 20:1;

[0105] The solvent was divided into two equal parts, one of the solvents was mixed with the resin binder, and then the mixture was stirred for 2 hours at a temperature of 80°C and a stirring speed of 220 r / min, and then the composite quantum dots were added, and the mixture was sheared and dispersed for 30 minutes at a shear rate of 4000 r / min, and then the other solvent and anionic surfactant were added, and the mixture was sheared and dispersed for 20 minutes, and then the material was discharged to obtain the reflector printing quantum dot ink;

[0106] The solvent includes cyclohexane, n-tridecane and n-nonane; wherein the mass ratio of the three is cyclohexane: n-tridecane: n-nonane=0.9:2.1:4.4;

[0107] The resin adhesive is a mixture of bisphenol A epoxy resin, terpene resin and C5 petroleum resin in a mass ratio of 2.2:0.6:0.3;

[0108] The anionic surfactant is selected from sodium fatty alcohol polyoxyethylene ether sulfate.

[0109] Example 4

[0110] Compared with Example 1, this embodiment is different in that:

[0111] After mixing the flaky nano zinc oxide dispersion and the polymethyl methacrylate solution at a mass ratio of 1:2.6, spray drying was performed under the conditions of an inlet air temperature of 130°C, an outlet air temperature of 110°C, a feed rate of 50g / min, and a main disk speed of 8000r / min to obtain pretreated flaky nano zinc oxide;

[0112] The amount of polymethyl methacrylate relative to the flaky nano zinc oxide is adjusted, and a spray drying process is adopted so that the polymethyl methacrylate completely covers the surface of the flaky nano zinc oxide.

[0113] Example 5

[0114] Compared with Example 1, this embodiment is different in that:

[0115] The flake-shaped nano-zinc oxide and the quasi-spherical nano-zinc oxide were not pre-coated with polymethyl methacrylate, and the other conditions remained unchanged.

[0116] Comparative Example 1

[0117] Compared with Example 1, this comparative example has the following differences:

[0118] No flaky nano zinc oxide was added, and the other conditions remained unchanged.

[0119] Comparative Example 2

[0120] Compared with Example 1, this comparative example has the following differences:

[0121] The D50 of the flaky nano zinc oxide is 1 nm;

[0122] The D50 of the quasi-spherical nano zinc oxide is 10 nm;

[0123] The rest of the conditions remain unchanged.

[0124] The ink products obtained in the above examples and comparative examples were subjected to performance tests, and the specific test methods and test results are as follows:

[0125] ITO is used as the substrate and cathode, zinc oxide is used as the electron transport layer and hole blocking layer, and the light-emitting layer adopts CdSeS@ZnS red quantum dots, whose emission wavelength, fluorescence quantum yield and half-height width are 624nm, 96% and 24nm respectively.

[0126] MoO3 and TCTA obtained by thermal evaporation were used as hole injection layer and transport layer respectively. Finally, Al was prepared as anode by mask thermal evaporation.

[0127] In addition, the ink obtained in the above embodiment or comparative example was printed between zinc oxide and the luminescent layer, and the thickness of the printed ink after drying was 0.5 mm; 10 parallel samples were printed in the same embodiment, and the average value, maximum value and minimum value were obtained in the subsequent photoelectric performance test;

[0128] The photoelectric performance of the device was measured using a constant current source (2400 model, Keithley, USA) in combination with a brightness meter (LS-160 model, Konica Mi-nolta, Japan). After the device voltage was increased to 3.5 V, its current density was detected. For details, see Table 1.

[0129] Table 1: Product performance test results

[0130]

[0131] It can be seen from the test results in Table 1 that the product obtained by the present invention not only has a relatively better average current density, but also, in the 10 groups of parallel samples, the difference between the maximum and minimum values ​​is relatively smaller. That is to say, after the product is dispersed, a more stable photoelectric performance can be obtained during the printing process.

[0132] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A reflective sheet printed with quantum dot ink, characterized in that: Including composite quantum dots and basic ink; Wherein, the composite quantum dots include flaky nano zinc oxide and spherical nano zinc oxide; The amount of the spherical nano zinc oxide is 30-40% of the mass of the flaky nano zinc oxide; The D50 of the quasi-spherical nano zinc oxide is 1-2 nm; the sphericity of the quasi-spherical nano zinc oxide is 8.5-9.5; The D50 of the flaky nano zinc oxide is 10-15 nm; The basic ink comprises a solvent, a resin binder of 15-20% by weight of the solvent, and an anionic surfactant of 4-6% by weight of the solvent; The mass ratio of the basic ink to the composite quantum dots is 18-20:

1.

2. The reflector printed quantum dot ink according to claim 1, characterized in that: The composite quantum dot also includes a coating layer on the surface, and the coating layer is polymethyl methacrylate.

3. The reflector printed quantum dot ink according to claim 2, characterized in that: The polymethyl methacrylate is coated on the surface of the flaky nano zinc oxide in an island shape; and the polymethyl methacrylate is completely coated on the surface of the spherical nano zinc oxide.

4. The reflective sheet printing quantum dot ink according to claim 2, characterized in that: A silane coupling agent is also included between the composite quantum dots and the coating layer; the silane coupling agent is selected from any one of silane coupling agent KH-540, silane coupling agent KH-550, silane coupling agent KH-560, silane coupling agent KH-570, and silane coupling agent KH-580.

5. The reflective sheet printing quantum dot ink according to claim 1, characterized in that: The solvent includes cyclohexane, n-tridecane and n-nonane; wherein the mass ratio of the three is cyclohexane:n-tridecane:n-nonane=0.8-0.9:1.9-2.1:4.2-4.

4.

6. The reflector printed quantum dot ink according to claim 1, characterized in that: The resin adhesive is prepared by mixing bisphenol A epoxy resin, terpene resin and C5 petroleum resin in a mass ratio of 2.0-2.2:0.5-0.6:0.2-0.

3.

7. The reflective sheet printing quantum dot ink according to claim 1, characterized in that: The anionic surfactant is selected from any one of sodium dodecylbenzene sulfonate, sodium stearate, sodium fatty alcohol polyoxyethylene ether sulfate, and sodium dodecyl sulfate.

8. A method for preparing a reflective sheet printing quantum dot ink according to any one of claims 1 to 7, characterized in that: The specific preparation steps include: Preparation of composite quantum dots: Ultrasonic dispersion of flaky nano zinc oxide and spherical nano zinc oxide in water to obtain a dispersion; the ultrasonic frequency is 200-250kHz, and the ultrasonic time is 1.5-2.5h; The dispersion was filtered and then freeze-dried in vacuum to obtain composite quantum dots; Ink preparation: The solvent is divided into two equal parts, one of the solvents is first stirred and mixed with the resin binder, and then the composite quantum dots are added. After shearing and dispersing evenly, the other solvent and anionic surfactant are added. After further shearing and dispersing evenly, the material is discharged to obtain the reflective sheet printing quantum dot ink.

9. The method for preparing a reflective sheet printing quantum dot ink according to claim 8, characterized in that: The specific preparation steps also include: Dissolving polymethyl methacrylate in solvent A to obtain a polymethyl methacrylate solution with a mass fraction of 6-8%; The flaky nano zinc oxide and solvent A are mixed in a mass ratio of 1:10 and then dispersed by ultrasonication to obtain a flaky nano zinc oxide dispersion; The spherical nano zinc oxide and solvent A are mixed in a mass ratio of 1:8 and then dispersed by ultrasonication to obtain a spherical nano zinc oxide dispersion; The flaky nano zinc oxide dispersion and the polymethyl methacrylate solution are mixed at a mass ratio of 1:1.2-1.5, and then spray-dried to obtain pretreated flaky nano zinc oxide; The spherical nano zinc oxide dispersion and the polymethyl methacrylate solution are mixed at a mass ratio of 1:2.0-2.5, and then spray-dried to obtain pretreated spherical nano zinc oxide; Ultrasonic dispersion of the pretreated flaky nano zinc oxide and the pretreated spherical nano zinc oxide in water to obtain a dispersion; the ultrasonic frequency is 200-250 kHz, and the ultrasonic time is 1.5-2.5 h; The dispersion was filtered and then freeze-dried in vacuum to obtain composite quantum dots; Wherein, the solvent A is selected from any one of acetone, dimethylformamide, dichloroethane, tetrahydrofuran and ethyl acetate.

10. The method for preparing a reflective sheet printing quantum dot ink according to claim 9, characterized in that: The specific preparation steps also include: The flaky nano zinc oxide and solvent A are mixed in a mass ratio of 1:10, and then ultrasonically dispersed, and a silane coupling agent is added in an amount of 3-5% by mass of the flaky nano zinc oxide to obtain a flaky nano zinc oxide dispersion; The spherical nano zinc oxide and solvent A are mixed in a mass ratio of 1:8, dispersed by ultrasonication, and a silane coupling agent of 3-5% of the mass of the spherical nano zinc oxide is added to obtain a spherical nano zinc oxide dispersion.

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