Quantum dot color conversion device preparation method and display panel comprising same

Abstract

The invention provides a preparation method of a quantum dot color conversion device and a display panel containing the quantum dot color conversion device. According to the preparation method, a first positive photoresist curing layer is obtained through first exposure and development, a first quantum dot layer is obtained through second exposure and development, the first positive photoresist curing layer is removed through third exposure and development, and residual quantum dot negative photoresist is eluted along with elution of the first positive photoresist curing layer. Therefore, the technical effect of few developing residues is achieved.

Description

Technical Field

[0001] This application relates to the field of quantum dot color conversion technology, and more specifically, to a method for preparing a quantum dot color conversion device and a display panel containing the same. Background Technology

[0002] Currently, quantum dot color conversion technology is widely used in the market to achieve high color gamut displays, such as OLED superimposed with quantum dot color conversion, or microLED superimposed with quantum dot color conversion. However, using quantum dot materials for color conversion brings other problems, the most prominent of which is how to ensure blue light absorption while addressing the issue of photoresist residue during development. Summary of the Invention

[0003] The purpose of this application is to provide a color conversion substrate, a method for preparing the same, and a display panel containing the same, to solve the technical problem of how to ensure the development of photoresist residue while ensuring blue light absorption.

[0004] To address the aforementioned technical problems, a first aspect of this application provides a method for fabricating a quantum dot color conversion device. The method comprises: providing a substrate; depositing a first positive photoresist layer on the substrate; placing a first photomask above the substrate; exposing and developing the first positive photoresist layer to obtain a first positive photoresist cured layer with multiple first pits, the positions of the first pits corresponding to the through-holes of the first photomask; and depositing a first quantum dot negative photoresist on the first positive photoresist cured layer with multiple first pits, a portion of the first quantum dot negative photoresist located within the multiple first pits, and another portion of the first quantum dot negative photoresist located within the first... On the surface of the positive photoresist cured layer away from the substrate, the first quantum dot negative photoresist includes first scattering particles; the first quantum dot negative photoresist is exposed using a second mask, the position of the first pit corresponds to the through hole of the second mask, and after development, multiple cured first quantum dot layers located on the first pit are obtained; a third mask is placed above the substrate, the third mask is opaque at the first pit, the first positive photoresist cured layer is exposed and then developed, the residual first quantum dot negative photoresist on the surface of the first positive photoresist cured layer away from the substrate is washed away with the washing of the first positive photoresist cured layer, and the first quantum dot color conversion device is obtained.

[0005] Furthermore, the fabrication method further includes: depositing a second positive photoresist layer on the first quantum dot color conversion device; placing a fourth mask above the substrate, performing exposure treatment, and then developing to obtain a second positive photoresist curing layer with multiple second pits, the positions of the second pits corresponding to the through holes of the fourth mask; depositing a second quantum dot negative photoresist on the second positive photoresist curing layer with multiple second pits, a portion of the second quantum dot negative photoresist being located within the second pits, and another portion of the second quantum dot negative photoresist being located on the surface of the second positive photoresist curing layer away from the substrate, the second quantum dot negative photoresist being... The photoresist includes second scattering particles; the second quantum dot negative photoresist is exposed using a fifth mask, the position of the second pit corresponds to the through hole of the fifth mask, and after development, multiple solidified second quantum dot layers are obtained on the second pits; a sixth mask is placed above the substrate, the sixth mask is opaque at the second pits, the second positive photoresist solidified layer is exposed and then developed, the residual second quantum dot negative photoresist on the surface of the second positive photoresist solidified layer away from the substrate is washed away with the second positive photoresist solidified layer, and the second quantum dot color conversion device is obtained.

[0006] Furthermore, the content of the first scattering particles in the first quantum dot negative photoresist is 12-20%.

[0007] Furthermore, the thickness of the first positive photoresist curing layer is greater than or equal to 0.3 micrometers, preferably 0.5 to 1 micrometer.

[0008] Furthermore, the thickness of the first quantum dot layer is 2 to 10 micrometers.

[0009] Furthermore, the first positive photoresist is selected from diazonaphthoquinone or polymethyl methacrylate.

[0010] Furthermore, the developing solution used is an aqueous solution of TMAH or an aqueous solution of KOH.

[0011] Furthermore, the spacing between each quantum dot layer is 1 to 5 micrometers.

[0012] Furthermore, the thickness of the first positive photoresist curing layer is less than or equal to the thickness of the first quantum dot layer.

[0013] A second aspect of this application provides a display panel, which includes a quantum dot color conversion device prepared by any of the above-described preparation methods, and also includes a plurality of light-emitting devices located on any side of a substrate; the light-emitting devices correspond to each quantum dot layer to excite the quantum dot layers.

[0014] By applying the above technical solution, high blue light absorption can be achieved while meeting the requirement of low photoresist development residue. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0016] Figure 1 This is a schematic diagram illustrating the fabrication process of color conversion devices according to some embodiments of this application.

[0017] Figure 2 For some embodiments of this application Figure 1 A schematic diagram of the fabrication process for preparing a green quantum dot layer based on this.

[0018] Figure 3 The diagram shows the structure of a display panel according to some embodiments of this application (arrows indicate the direction of light emission).

[0019] Figure 4 Microscopic photographs of the color conversion devices of Embodiment 1 and Comparative Example 2 of this application.

[0020] Figure 5 Microscopic photographs of the color conversion devices of Embodiment 6 and Comparative Example 4 of this application.

[0021] 11. Substrate; 12. First positive photoresist layer; 12'. First positive photoresist cured layer; 13. First quantum dot negative photoresist; 13G. Green quantum dot negative photoresist; 13'. First quantum dot layer; 13'R. Red quantum dot layer; 13'G. Green quantum dot layer; 13'B. Blue blank layer; 14. Second positive photoresist layer; 14'. Second positive photoresist cured layer; 15. Pixel definition layer; 21. First mask; 22. Second mask; 23. Third mask; 24. Fourth mask; 25. Fifth mask; 26. Sixth mask; 31. Light-emitting device substrate; 32. Light-emitting device; 33. Transparent dielectric layer. Detailed Implementation

[0022] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0023] According to a first aspect of this application, a method for fabricating a quantum dot color conversion device is provided. The method includes: providing a substrate; depositing a first positive photoresist layer on the substrate; placing a first mask above the substrate; exposing and developing the first positive photoresist layer to obtain a first positive photoresist cured layer having multiple first pits, the positions of the first pits corresponding to the through-holes of the first mask; depositing a first quantum dot negative photoresist on the first positive photoresist cured layer having multiple first pits, a portion of the first quantum dot negative photoresist being located within the multiple first pits, and another portion of the first quantum dot negative photoresist being located away from the first positive photoresist cured layer. On the surface away from the substrate, a first quantum dot negative photoresist includes first scattering particles. The first quantum dot negative photoresist is exposed and developed using a second mask, with the location of the first pit corresponding to a through-hole in the second mask. After development, multiple cured first quantum dot layers are obtained located on the first pits. A third mask is placed above the substrate, and the third mask is opaque at the first pits. The cured first positive photoresist layer undergoes exposure and development. Residual first quantum dot negative photoresist on the surface of the cured first positive photoresist layer away from the substrate is washed away along with the cured first positive photoresist layer, resulting in a first quantum dot color conversion device. The above fabrication process can be combined with... Figure 1 Understood. By applying the above technical solution, high blue light absorption can be achieved while meeting the requirement of minimal photoresist residue during development.

[0024] There are no restrictions on the method of setting the positive photoresist layer and the quantum dot negative photoresist; it can be spin coating, coating, etc.

[0025] In some embodiments, the fabrication method of the color conversion device further includes: depositing a second positive photoresist layer on the first quantum dot color conversion device; placing a fourth mask above a substrate, performing exposure treatment, and then developing to obtain a second positive photoresist curing layer with multiple second pits, the positions of the second pits corresponding to the through holes of the fourth mask; depositing a second quantum dot negative photoresist on the second positive photoresist curing layer with multiple second pits, a portion of the second quantum dot negative photoresist being located within the second pits, and another portion of the second quantum dot negative photoresist being located on the surface of the second positive photoresist curing layer away from the substrate, the second... The quantum dot negative photoresist includes second scattering particles. The second quantum dot negative photoresist is exposed using a fifth mask, with the second pits corresponding to the through-holes of the fifth mask. After development, multiple cured second quantum dot layers are obtained located on the second pits. A sixth mask is placed above the substrate, and the sixth mask is opaque at the second pits. The cured second positive photoresist layer is exposed and then developed. Residual second quantum dot negative photoresist on the surface of the cured second positive photoresist layer away from the substrate is washed away along with the cured second positive photoresist layer, yielding a second quantum dot color conversion device. The above fabrication process can be combined with... Figure 2understand.

[0026] In some embodiments, the method for fabricating the color conversion device further includes: fabricating a blue blank layer on the second quantum dot color conversion device, the fabrication method of which is conventional photolithography, and will not be described in detail here; the photoresist formulation of the blue blank layer can refer to the prior art.

[0027] In some embodiments, the content of quantum dots in the first or second quantum dot negative photoresist is 10-60% or 20-50%.

[0028] In some embodiments, the content of the first scattering particles in the first quantum dot negative photoresist is 12-20%. In some embodiments, the content of the second scattering particles in the second quantum dot negative photoresist is 12-20%.

[0029] In some embodiments, the thickness of the first positive photoresist cured layer is greater than or equal to 0.3 micrometers, preferably 0.5 to 1 micrometer. In some embodiments, the thickness of the second positive photoresist cured layer is greater than or equal to 0.3 micrometers, preferably 0.5 to 1 micrometer.

[0030] In some embodiments, the thickness of the first quantum dot layer and the second quantum dot layer is independently 2 to 10 micrometers. In some embodiments, the thickness of the first and second quantum dot layers is 2 to 6 micrometers.

[0031] In some embodiments, the first or second positive photoresist is selected from diazonaphthoquinone or polymethyl methacrylate.

[0032] In some embodiments, the developing solution used for developing is an aqueous solution of TMAH or an aqueous solution of KOH.

[0033] In some embodiments, the spacing between the individual quantum dot layers is 1 to 5 micrometers. For example... Figure 1 The lateral spacing between the two quantum dot layers in the cross-section.

[0034] In some embodiments, the thickness of the first positive photoresist cured layer is less than or equal to the thickness of the first quantum dot layer. In some embodiments, the thickness of the second positive photoresist cured layer is less than or equal to the thickness of the second quantum dot layer.

[0035] The material of the substrate is not limited and can be a combination of inorganic and organic compounds. The structure of the substrate can be designed according to requirements, such as adding color filter layers. In some embodiments, the substrate includes a smoothing layer, a red color filter layer, a green color filter layer, a blue color filter layer, a light-blocking layer, and a transparent substrate (light-emitting side) arranged sequentially, with the color filter layers and quantum dot layers corresponding one-to-one to match the application requirements of the display panel.

[0036] The shape of a single quantum dot layer is not limited; it can be circular, square, rectangular, or elongated. The shape of a single quantum dot layer can be controlled by the surface properties of the quantum dots or by defining a pixel layer.

[0037] In some embodiments, the first or second scattering particle is selected from inorganic scattering particles, such as TiO2, SiO2, BaTiO3, BaO, ZnO, Al2O3, and hollow silicon dioxide.

[0038] In some embodiments, the scattering particles may include a variety of scattering particles, and the median diameter (D50) of the variety of scattering particles may be in the range of about 50 nm to about 500 nm. The first scattering particle and the second scattering particle may be the same or different.

[0039] In some embodiments, the quantum dots in the quantum dot negative photoresist are selected from group II-VI semiconductor compounds, group I-II-VI semiconductor compounds, group II-IV-VI compounds, group I-II-IV-VI semiconductor compounds, group III-V semiconductor compounds, group III-II-V semiconductor compounds, group III-VI semiconductor compounds, group I-III-VI semiconductor compounds, group IV-VI semiconductor compounds, group II-IV-V semiconductor compounds, group IV semiconductor compounds, group IV elements, mixtures thereof, and compounds thereof.

[0040] The full width at half maximum (FWHM) of the emission spectrum of quantum dots can be less than or equal to about 45 nm. For example, the FWHM of the emission spectrum of quantum dots can be less than or equal to about 40 nm. For example, the FWHM of the emission spectrum of quantum dots can be less than or equal to about 30 nm. Within this range, color purity or color reproducibility can be improved. Light emitted through such quantum dots can be emitted in all directions, and the viewing angle can be improved. The shapes of quantum dots can be spherical, pyramidal, multi-armed, cubic nanoparticles, nanotubes, nanowires, nanofibers, nanoplate particles, etc.

[0041] In some embodiments, the first quantum dot layer and the second quantum dot layer further include a dispersant. The dispersant may be selected from one or more of alkyl acrylate phosphates and 2-hydroxyethyl methacrylate phosphates. For example, PM1560, PM1590, PM1510SP, PM1500EC, or PM2010SP from Zhejiang Jingde Chemical Materials Co., Ltd.

[0042] In some embodiments, the first quantum dot layer and the second quantum dot layer are selected from a red quantum dot layer and a green quantum dot layer. The thicknesses of the different colored quantum dot layers can be the same or different. The blue blank layer can be composed of a light-transmitting medium, and the blue light is provided by a backlight-emitting device. The red quantum dot layer, the green quantum dot layer, and the blue blank layer can be defined by a pixel definition layer.

[0043] The pixel definition layer can be formed using a polymer resin. For example, the pixel definition layer may contain a polyacrylate-based resin or a polyimide-based resin. In another embodiment, the pixel definition layer may contain inorganic materials in addition to the polymer resin. In one embodiment, the pixel definition layer may contain a light-absorbing material, a black pigment, or a black dye. A pixel definition layer containing a black pigment or black dye may be a black pixel definition layer. Carbon black or the like can be used as the black pigment or black dye when forming the pixel definition layer, but this disclosure is not limited thereto.

[0044] In some embodiments, and in another embodiment, the pixel definition layer may include an inorganic material. For example, the pixel definition layer may include silicon nitride (SiN). x Inorganic materials such as silicon dioxide (SiO2) x ), silicon oxynitride (SiO) x N y (or similar items)

[0045] In some embodiments, the pixel definition layer is prepared during the substrate preparation stage and obtained by photolithography.

[0046] According to a third aspect of this application, a display panel is provided, the display panel including a quantum dot color conversion device prepared by the above-described preparation method, and further including a plurality of light-emitting devices located on any side of a substrate; the light-emitting devices correspond to each quantum dot layer to excite the quantum dot layer.

[0047] The light-emitting device can be an LED (microLED, etc.), a QLED, or an OLED. The light-emitting device can be a blue light conversion device.

[0048] In some embodiments, such as Figure 3 As shown, the light-emitting device is disposed on the side of the substrate away from the quantum dot layer. In some embodiments, the light-emitting device is disposed on the same side of the substrate as the quantum dot layer shown.

[0049] The connection method between the light-emitting device and the color-converting device refers to existing technology. In some embodiments, the color-converting device and the light-emitting device are connected through a transparent dielectric layer, such as... Figure 3 As shown.

[0050] In some embodiments, the transparent dielectric layer may serve at least one function as an adhesive or encapsulator. The transparent dielectric layer may comprise multiple layers or materials, or it may function as an impact absorber and enhance the strength of the display panel. The transparent dielectric layer may be formed from a filler resin containing a polymer resin. For example, the transparent dielectric layer may be formed from a filler resin containing acrylic resin, epoxy resin, etc.

[0051] The implementation methods are described in more detail below with reference to specific embodiments. However, these are exemplary examples of the content of this application, and the content of this application is not limited thereto.

[0052] Quantum dot photoresist solution (QDPR) preparation:

[0053] Weigh 2.4g of a 40% PGMEA solution containing scattering particles (titanium dioxide particles with an average particle size of 100-300nm) and add it dropwise to a 40% quantum dot PGMEA solution containing 12.6g of PGMEA solvent. Stir until homogeneous. Next, add 15g of an acrylic resin negative photoresist solution (40% solids content) and stir until homogeneous to prepare the final quantum dot photoresist solution. After PGMEA evaporation, the corresponding dry film quantum dot concentration is 42% and the scattering particle concentration is 8%, abbreviated as Q42% / S8%. For other concentrations of QDPR, refer to the aforementioned method. The quantum dots in the same colored PGMEA are identical.

[0054] Example 1

[0055] S1: Place a 5*5*0.05cm glass slide onto the vacuum chuck of the spin coater, and use a pipette to drop 100μL of positive photoresist (diazonaphthoquinone (DNQ)) onto the center of the glass slide; Spin coating: Adjust the spin speed to 4000rpm / min, the acceleration to 200rpm / s, and the time to 30s to perform spin coating.

[0056] S2: Pre-baking: Place the glass slide with the positive photoresist layer on the hot stage and bake at 100℃-120℃ for 5 minutes to remove most of the solvent;

[0057] S3: Contact exposure, 365nm UV curing, constant instrument power (100mJ-1000mJ) exposure amount, different exposure amounts are achieved by adjusting the exposure time. The exposure amount in this case is 300mJ, and the same applies below.

[0058] S4: Immersion development, immerse the film in 2.38% TMAH developer for 60 seconds to wash away the photoresist layer in the exposed area, leaving the mask pattern in the non-exposed area;

[0059] S5: Post-baking: Place the glass slide on a 130℃ heating stage for annealing for 10 minutes to remove residual solvent and achieve a hardened film. Use a step meter to measure the film thickness and record the data.

[0060] S6: Adsorb the glass slide patterned with the above positive photoresist onto the vacuum chuck of the spin coater, and drop 150μL of green QDPR (Q38% / S12%) onto the center of the glass slide using a pipette; Spin coating: Adjust the rotation speed to 1000rpm / min, the acceleration to 200rpm / s, and the time to 30s to perform spin coating.

[0061] S7: Pre-baking, place the film on a hot plate and bake at 100℃-120℃ for 5 minutes to remove most of the solvent;

[0062] S8: Contact exposure, 365nm UV curing, constant instrument power (100mJ-1000mJ) exposure, different exposure amounts can be achieved by adjusting the exposure time;

[0063] S9: Immersion development, immersing the film in 0.045% KOH developer for 60 seconds to wash away excess photoresist layer in the unexposed area, leaving the photomask pattern;

[0064] S10: Contact exposure of positive photoresist area, 365nm UV curing, 300mJ exposure;

[0065] S11: Immersion development, immersing the film in 2.38% TMAH developer for 60 seconds to wash away the positive photoresist layer in the exposed area and completely remove the green QDPR residue;

[0066] S12: Post-baking: Place the glass slide on a 130℃ heating table for annealing for 30 minutes to remove residual solvent and achieve a hardened film effect.

[0067] S13: Measure film thickness using a profilometer and record the data; measure the linewidth CD of the photolithographic pattern under a microscope and observe the pattern morphology and development residue.

[0068] Example 2

[0069] The difference from Example 1 is that the spin coating speed in S1 is 2500 rpm / min.

[0070] Example 3

[0071] The difference from Example 1 is that the spin coating speed in S1 is 1200 rpm / min.

[0072] Example 4

[0073] The difference from Example 1 is that (Q35% / S15%) green QDPR is used, and the spin coating speed in S1 is 2500 rpm / min.

[0074] Example 5

[0075] The difference from Example 1 is that (Q30% / S20%) green QDPR is used, and the spin coating speed in S1 is 2500 rpm / min.

[0076] Example 6

[0077] The difference from Example 1 is that in S1 to S13, the green QDPR is replaced with (Q38% / S12%) red QDPR; after completing S1 to S13, S1 to S13 are repeated again, using (Q38% / S12%) green QDPR, and the two-color overlay process can be completed.

[0078] Example 7

[0079] The difference from Example 1 is that in S1 to S13, the green QDPR is replaced with (Q35% / S15%) red QDPR; after completing S1 to S13, S1 to S13 are repeated again, using (Q35% / S15%) green QDPR, and the two-color overlay process can be completed.

[0080] Example 8

[0081] The difference from Example 1 is that in S1 to S13, the green QDPR is replaced with (Q30% / S20%) red QDPR; after completing S1 to S13, S1 to S13 are repeated again, using (Q30% / S20%) green QDPR, and the two-color overlay process can be completed.

[0082] Comparative Example 1

[0083] S1: Place a 5*5*0.05cm glass slide onto the vacuum suction cup of the spin coater. Use a pipette to drop 150μL of green QDPR (Q30% / S20%) onto the center of the glass slide. Adjust the rotation speed to 1000rpm / min, the acceleration to 200rpm / s, and the time to 30s to perform spin coat.

[0084] S2: Pre-baking: Place the glass slide with the wet film on a hot stage and bake at 100℃-120℃ for 5 minutes to remove most of the solvent; measure the film thickness with a step meter and record the data.

[0085] S3: Contact exposure, 365nm UV curing, 300mJ exposure;

[0086] S4: Immersion development, immerse the glass slide from S3 in 0.045% KOH developer for 60 seconds to wash away excess photoresist layer in the unexposed area, leaving the photomask pattern;

[0087] S5: Post-baking: Place the glass slide on a 130℃ heating table for annealing for 30 minutes to remove residual solvent and achieve a hardened film effect.

[0088] S6: Measure film thickness using a profilometer and record the data; measure the linewidth CD of the photolithographic pattern under a microscope and observe the pattern morphology and development residue.

[0089] Comparative Example 2

[0090] The difference from Comparative Example 1 is that (Q38% / S12%) green QDPR is used.

[0091] Comparative Example 3

[0092] The difference from Comparative Example 1 is that (Q42% / S8%) green QDPR is used.

[0093] Comparative Example 4

[0094] The difference from Comparative Example 1 is that the green QDPR is replaced with red QDPR in S1 to S6; after completing S1 to S6, continue to repeat S1 to S6, using green QDPR, and the two-color overlay process can be completed.

[0095] Performance testing

[0096] The exposed but undeveloped green or dual-color quantum dot glass slides from the examples and comparative examples were placed in a large integrating sphere, and their blue light absorption rate was tested. The residue was observed under a microscope. The color mixing of the dual-color conversion device was tested in two ways: one was with the aid of a first positive photoresist curing layer, where a red quantum dot negative photoresist layer was directly applied without exposure and development, followed by overall exposure, development, and elution, then a green quantum dot negative photoresist layer was applied, and the process was repeated with exposure, curing, and integrating sphere spectroscopy. The other method involved no positive photoresist curing layer, directly applying a red quantum dot negative photoresist layer, developing and eluting without exposure, then applying a green quantum dot negative photoresist layer, and repeating the process with exposure, curing, and integrating sphere spectroscopy. The color mixing ratio was calculated as: red spectral area / green spectral area in the green pixel. The results are shown in Tables 1 and 2.

[0097] Table 1

[0098]

[0099] Table 2

[0100]

[0101] Results analysis:

[0102] Positive photoresist curing layer assistance can solve the residue problem of negative quantum dot photoresist under high blue light absorption, especially the residue problem in two-color overlay. Experimental results show that without positive photoresist curing layer assistance, the higher the concentration of scattered particles in the quantum dot photoresist, the more obvious the residue. 8% scattered particles result in virtually no residue, but blue light absorption is low, only 84.3%. When the scattered particle concentration reaches 12%, residue is quite noticeable after QDPR exposure and development. When the scattered particle concentration further reaches 20%, residue after QDPR exposure and development is extremely severe, but blue light absorption can reach 98.5%. Therefore, this application uses positive photoresist curing layer assistance to solve this problem. When the thickness of the positive photoresist curing layer is 0.3µm, the residue problem is lessened but not completely solved (Example 1), see [link to example]. Figure 4 When the thickness of the positive photoresist cured layer is 0.5µm or greater, the residue problem after QDPR exposure and development can be completely solved. Simultaneously, the red-green quantum dot crosstalk problem caused by residue (Comparative Example 4) can also be effectively resolved. See [link to relevant documentation]. Figure 5 .

[0103] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for fabricating a quantum dot color conversion device, characterized in that, The preparation method includes: A substrate is provided, on which a first positive photoresist layer is disposed; A first photomask is placed above the substrate, and the first positive photoresist layer is exposed and developed to obtain a first positive photoresist cured layer with multiple first pits, the positions of the first pits corresponding to the through holes of the first photomask. A first quantum dot negative photoresist is disposed on the first positive photoresist curing layer having a plurality of first pits. A portion of the first quantum dot negative photoresist is located within the plurality of first pits, and another portion of the first quantum dot negative photoresist is located on the surface of the first positive photoresist curing layer away from the substrate. The first quantum dot negative photoresist includes first scattering particles. The first quantum dot negative photoresist is exposed using a second mask, and the position of the first pit corresponds to the through hole of the second mask. After development, a plurality of solidified first quantum dot layers are obtained on the first pit. A third mask is placed above the substrate. The third mask is opaque at the first recess. After the first positive photoresist curing layer is exposed, it is developed. The residual first quantum dot negative photoresist on the surface of the first positive photoresist curing layer away from the substrate is washed away along with the first positive photoresist curing layer, thus obtaining the first quantum dot color conversion device.

2. The preparation method according to claim 1, characterized in that, The preparation method further includes: A second positive photoresist layer is disposed on the first quantum dot color conversion device; The fourth photomask is placed above the substrate, and after exposure and development, a second positive photoresist curing layer with multiple second pits is obtained, the positions of the second pits corresponding to the through holes of the fourth photomask. A second quantum dot negative photoresist is disposed on the second positive photoresist curing layer having a plurality of second pits. A portion of the second quantum dot negative photoresist is located in the second pits, and another portion of the second quantum dot negative photoresist is located on the surface of the second positive photoresist curing layer away from the substrate. The second quantum dot negative photoresist includes second scattering particles. The second quantum dot negative photoresist is exposed using a fifth mask, and the position of the second pit corresponds to the through hole of the fifth mask. After development, multiple solidified second quantum dot layers are obtained on the second pit. A sixth mask is placed above the substrate. The sixth mask is opaque at the second recess. After the second positive photoresist curing layer is exposed, it is developed. The residual second quantum dot negative photoresist on the surface of the second positive photoresist curing layer away from the substrate is washed away along with the second positive photoresist curing layer, thus obtaining the second quantum dot color conversion device.

3. The preparation method according to claim 1, characterized in that, The content of the first scattering particles in the first quantum dot negative photoresist is 12-20%.

4. The preparation method according to claim 1, characterized in that, The thickness of the first positive photoresist curing layer is greater than or equal to 0.3 micrometers, preferably 0.5 to 1 micrometer.

5. The preparation method according to claim 1, characterized in that, The thickness of the first quantum dot layer is 2 to 10 micrometers.

6. The preparation method according to claim 1, characterized in that, The first positive photoresist is selected from diazonaphthoquinone or polymethyl methacrylate.

7. The preparation method according to claim 1, characterized in that, The developing solution used is an aqueous solution of TMAH or an aqueous solution of KOH.

8. The preparation method according to claim 1, characterized in that, The spacing between each quantum dot layer is 1 to 5 micrometers.

9. The preparation method according to claim 1, characterized in that, The thickness of the first positive photoresist cured layer is less than or equal to the thickness of the first quantum dot layer.

10. A display panel, characterized in that, The display panel includes a quantum dot color conversion device prepared by any one of claims 1 to 9, and further includes a plurality of light-emitting devices located on any side of the substrate; the light-emitting devices correspond to each of the quantum dot layers to excite the quantum dot layers.

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