A method and apparatus for fabricating high-resolution full-color quantum dot light emitting diodes

Abstract

The application discloses a method and equipment for preparing a high-resolution full-color quantum dot light-emitting diode, which comprises the following steps of preparing a substrate, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer and encapsulating the equipment, and can greatly improve the quantum dot transfer speed and transfer precision, and also increases the robustness and repeatability of the preparation process, and therefore, in the field of quantum dot photoelectricity, the application has unique advantages and innovation points compared with traditional preparation methods, and can greatly improve the performance and application prospect of the light-emitting diode in the application fields of full-color display, background illumination, biological imaging and the like.

Description

TECHNICAL FIELD

[0001] The application relates to a method and equipment for preparing a high-resolution full-color quantum dot light-emitting diode, and belongs to the technical field of light-emitting devices. BACKGROUND

[0002] In the past, no good method for preparing a high-resolution full-color quantum dot light-emitting diode has been proposed. Traditional technologies, such as photolithography, can greatly reduce the performance of quantum dots, spin coating cannot realize full-color display, inkjet printing faces great difficulties in the nozzle and equipment below several microns of pixels, in addition, the traditional transfer method can cause the pixel points to be difficult to align, and the quantum dots are easily damaged, the electrical characteristics and stability are difficult to maintain, and the service life of the device is also affected, which is not suitable for large-scale industrial production. The full-color quantum dot light-emitting diode prepared by the prior art has low resolution, poor precision and complex process, and it has been difficult to realize the preparation of high-resolution light-emitting devices. SUMMARY

[0003] According to one aspect of the application, a method for preparing a high-resolution full-color quantum dot light-emitting diode is provided, comprising the following steps:

[0004] S1: preparing a substrate and pretreating the substrate to ensure that the surface is clean and free of contamination;

[0005] S2: spin coating a hole injection layer, spin coating a solution prepared from a hole injection layer material on the pretreated substrate, and performing annealing treatment on a heating table;

[0006] S3: spin coating a hole transport layer, spin coating a solution prepared from a hole transport layer material on the surface of the hole injection layer to generate an organic semiconductor thin film;

[0007] S4: preparing a quantum dot light-emitting layer on the surface of the hole transport layer, comprising:

[0008] Processing the first quantum dots, dissolving the first quantum dots in a first solvent to form a dense arrangement of thin film on the liquid surface, sticking the thin film, using a positioning camera to complete pixel transfer after pixel alignment, transferring the thin film to the substrate to form a first quantum dot matrix;

[0009] Processing the second quantum dots, dissolving the second quantum dots in a second solvent to form a dense arrangement of thin film on the liquid surface, sticking the thin film, using a positioning camera to complete pixel transfer after pixel alignment, transferring the thin film to the substrate to form a second quantum dot matrix;

[0010] The third quantum dots are processed, the third quantum dots are dissolved in a third solvent to form a dense arrangement film on a liquid surface, the film is adhered, pixel alignment is performed by using a positioning camera, pixel transfer is completed, the film is transferred to the substrate to form a third quantum dot matrix;

[0011] The first quantum dots, the second quantum dots, and the third quantum dots are different in color;

[0012] The first quantum dot matrix, the second quantum dot matrix, and the third quantum dot matrix are regularly arranged in an alternating manner in a horizontal direction of the hole transport layer;

[0013] After processing is completed, red, green, and blue pixels form RGB arrangement, dense arrangement, PenTile arrangement, and the like;

[0014] That is, the first quantum dots, the second quantum dots, and the third quantum dots are processed in the same manner, but the quantum dot types and specific arrangement directions are different;

[0015] S5: spin-coating an electron transport layer, a solution of an electron transport layer material is spin-coated on the surface of the quantum dot light-emitting layer, and annealing treatment is performed;

[0016] S6: preparing a metal electrode;

[0017] S7: packaging.

[0018] Optionally, the pretreatment in the step S1 comprises surface cleaning and processing of the substrate;

[0019] Preferably, the material of the substrate is ITO glass.

[0020] Optionally, the hole injection layer material in the step S2 is selected from one of PEDOT:PSS, molybdenum oxide, nickel oxide, and cuprous thiocyanate;

[0021] Preferably, the thickness of the hole injection layer is 20 nm to 30 nm.

[0022] Optionally, the hole transport layer material in the step S3 is selected from one or a mixture of several of polymer TFB, cross-linked TFB, Poly:TPD, and PVK;

[0023] Preferably, the thickness of the hole transport layer is 40 nm to 50 nm.

[0024] Optionally, the quantum dots in the step S4 are solution-processable and light-emitting materials capable of film drawing on a liquid surface, and are selected from one of cadmium quantum dots and indium phosphide quantum dots;

[0025] Preferably, the first solvent, the second solvent and the third solvent in the step S4 all have strong volatility and are independently selected from one of ethanol, diethyl ether, acetone, chloroform and benzene;

[0026] Preferably, the thin film is adhered by using a PDMS template.

[0027] Optionally, the electron transport layer material in the step S5 is selected from one of ZnO and zinc magnesium oxide.

[0028] Preferably, the thickness of the electron transport layer is 70-80 nm.

[0029] Optionally, the metal electrode in the step S6 is a silver electrode, and the preparation method specifically comprises the following steps:

[0030] Carrying out silver electrode evaporation on an evaporation machine;

[0031] Preferably, the thickness of the silver electrode is 90-100 nm.

[0032] Optionally, the device is packaged by using a transparent material in the step S7.

[0033] Preferably, the transparent material is selected from one of a polymer and glass.

[0034] The packaging can protect and fix the circuit and provide moisture-proof and environmental isolation.

[0035] The method provided in the application optimizes the arrangement mode of quantum dots, which helps to improve the resolution and stability of the light-emitting layer.

[0036] Compared with the traditional chip preparation process, the application adopts chemical synthesis technology and film drawing transfer technology, the required chemicals are reduced, and the waste generated in the preparation process is also relatively less, so it has better environmental performance.

[0037] The transfer method adopted in the application can greatly improve the transfer speed and transfer accuracy of quantum dots, and also increase the robustness and repeatability of the preparation process. Therefore, in the field of quantum dot optoelectronics, the application has unique advantages and innovation points compared with the traditional preparation method, which can greatly improve the performance and application prospect of light-emitting diodes in the application fields of full-color display, background lighting, biological imaging, etc.

[0038] In addition, the application also provides a device for realizing the above method, which comprises a damping platform.

[0039] The damping platform is provided with a motion assembly, and a positioning camera assembly and an observation camera assembly are movably arranged on the motion assembly.

[0040] A transfer head assembly is arranged near the positioning camera assembly.

[0041] The damping platform is further provided with a film pulling machine and a bearing jig assembly.

[0042] The positioning camera and the observation camera should at least be able to see the positioning marks of the pixel points and the substrate, and the objective lens should have a magnification of 50 times or more, and the CCD should have a magnification of 10 times.

[0043] Optionally, the motion assembly comprises an X-axis rail, two ends of the X-axis rail are movably provided with double-drive Y-axis rails, and a Z-axis rail is movably arranged on the X-axis rail.

[0044] The positioning camera assembly and the transfer head assembly are arranged on the Z-axis rail.

[0045] The observation camera assembly is arranged on the double-drive Y-axis rail.

[0046] The film pulling machine is arranged between the double-drive Y-axis rails.

[0047] The film pulling machine is a Langmuir-Blodgett film pulling machine, and the motion assembly is an XYZ three-axis high-precision motion system.

[0048] After the quantum dots are formed into a film by the film pulling machine, the quantum dots are adhered by the PDMS template arranged on the transfer head assembly, the positions of the transfer head and the substrate are observed by the high-resolution positioning camera, the contact between the PDMS template and the substrate during the descending process of the Z-axis rail is observed by the high-resolution observation camera, and the pixel offset adjustment in the X / Y direction is realized by the bearing jig assembly, so that the RGB three-color quantum dots are transferred.

[0049] For pixel offset adjustment, for example, it is assumed that the first quantum dots are transferred for the first time, and after being transferred to the substrate, the second color quantum dots (green) are grabbed by the stamp, the substrate is moved by X=xx um and Y=xx um, and then the second quantum dots are transferred, and the third quantum dots are also transferred according to the method, and the values of X and Y depend on the size and arrangement of the red, green and blue pixels and are preset.

[0050] The application can produce beneficial effects, including:

[0051] The application provides a method for preparing a high-resolution full-color quantum dot light-emitting diode.

[0052] (1) The arrangement of the quantum dots is optimized, the pixel points can be accurately aligned, which helps to improve the resolution and stability of the light-emitting layer, and effectively prolongs the service life of the device.

[0053] (2) Compared with the traditional chip preparation process, the chemical synthesis technology and the film drawing transfer technology are adopted in the present application, the required chemicals are reduced, the waste generated in the preparation process is relatively less, and therefore the present application has better environmental protection performance;

[0054] (3) The transfer method adopted in the present application can greatly improve the transfer speed and transfer precision of quantum dots, and also increase the robustness and repeatability of the preparation process. The method is simple, low in cost, fast, easy to operate and high in yield, and is very suitable for large-scale industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0055] Figure 1 An apparatus for implementing the method for preparing a high-resolution full-color quantum dot light-emitting diode provided in an embodiment of the present application.

[0056] List of components and reference numerals:

[0057] 1, shock-absorbing platform; 2, X-axis rail; 3, Y-axis rail; 4, Z-axis rail; 5, positioning camera assembly; 6, transfer head assembly; 7, observation camera assembly; 8, film drawing machine; 9, carrier jig assembly. DETAILED DESCRIPTION

[0058] The present application will be described in detail below with reference to examples, but the present application is not limited to these examples.

[0059] According to an embodiment of the present application, a method for preparing a high-resolution full-color quantum dot light-emitting diode is provided, comprising the following steps:

[0060] S1: preparing a substrate and pretreating the substrate, including surface cleaning and treatment to ensure that the surface is clean and free of contamination;

[0061] The material of the substrate is ITO glass;

[0062] S2: spin coating a hole injection layer, spin coating a solution prepared from a hole injection layer material on the pretreated substrate, and performing annealing treatment on a heating table;

[0063] The hole injection layer material is PEDOT:PSS;

[0064] The thickness of the hole injection layer is about 30 nm.

[0065] S3: spin coating a hole transport layer, spin coating a solution prepared from a hole transport layer material on the surface of the hole injection layer to generate an organic semiconductor thin film;

[0066] The hole transport layer material is TFB;

[0067] The thickness of the hole transport layer is about 50 nm.

[0068] S4: preparing a quantum dot light-emitting layer, preparing a quantum dot light-emitting layer on the surface of the hole transport layer, comprising:

[0069] Processing the first quantum dots, which are red quantum dots in this embodiment, dissolving the first quantum dots in a first solvent with strong volatility, which is ethanol in this embodiment, forming a dense arrangement film on the liquid surface, sticking the film, completing pixel transfer after pixel alignment using a positioning camera, and transferring the film to the substrate to form a first quantum dot matrix;

[0070] Processing the second quantum dots, which are green quantum dots in this embodiment, by the same method as above to form a second quantum dot matrix;

[0071] Processing the third quantum dots, which are blue quantum dots in this embodiment, by the same method as above to form a third quantum dot matrix;

[0072] The first quantum dot matrix, the second quantum dot matrix, and the third quantum dot matrix are regularly arranged in the horizontal direction on the surface of the hole transport layer;

[0073] The quantum dots of each color are solution-processable light-emitting materials that can be pulled on the liquid surface, and cadmium quantum dots are selected in this embodiment;

[0074] The film is stuck using a PDMS template;

[0075] S5: spin coating an electron transport layer, spin coating a solution of electron transport layer material on the surface of the quantum dot light-emitting layer and performing annealing treatment;

[0076] The electron transport layer material is selected to be ZnO;

[0077] The thickness of the electron transport layer is about 80 nm.

[0078] S6: preparing a metal electrode, the metal electrode is selected to be a silver electrode, and silver electrode evaporation is performed on an evaporation machine, and the thickness of the silver electrode is 100 nm;

[0079] S7: packaging, using a transparent material to package the device, and glass is selected in this embodiment.

[0080] Packaging can protect and fix the circuit and provide moisture-proof and environmental isolation.

[0081] The method provided in this application optimizes the arrangement of quantum dots, which helps to improve the resolution and stability of the light-emitting layer;

[0082] Compared with the traditional chip preparation process, the chemical synthesis technology and the film drawing transfer technology are adopted in the application, the required chemicals are reduced, the waste generated in the preparation process is relatively less, and therefore the application has better environmental protection performance.

[0083] The transfer method adopted in the application can greatly improve the transfer speed and transfer accuracy of quantum dots, and also increase the robustness and repeatability of the preparation process. Therefore, in the field of quantum dot optoelectronics, the application has unique advantages and innovation points compared with the traditional preparation method, and can greatly improve the performance and application prospect of light emitting diodes in the application fields of full-color display, background lighting, biological imaging, etc.

[0084] In addition, the application also provides a device for realizing the above method, as shown in the accompanying drawings, comprising a damping platform 1. Figure 1

[0085] The damping platform 1 is provided with a motion assembly, and a positioning camera assembly 5 and an observation camera assembly 7 are movably arranged on the motion assembly.

[0086] A transfer head assembly 6 is arranged near the positioning camera assembly 5.

[0087] The damping platform 1 is also provided with a film drawing machine 8 and a bearing jig assembly 9.

[0088] The motion assembly comprises an X-axis track 2, both ends of the X-axis track 2 are movably provided with a double-drive Y-axis track 3, and a Z-axis track 4 is movably arranged on the X-axis track 2.

[0089] The positioning camera assembly 5 and the transfer head assembly 6 are arranged on the Z-axis track 4.

[0090] The observation camera assembly 7 is arranged on the double-drive Y-axis track 3.

[0091] The film drawing machine 8 is arranged between the double-drive Y-axis tracks 3.

[0092] The film drawing machine 8 is selected as a Langmuir-Blodgett film drawing machine 8, and the motion assembly is an XYZ three-axis high-precision motion system.

[0093] After the quantum dots are formed into a film by the film drawing machine 8, the quantum dots are adhered by the PDMS template arranged on the transfer head assembly 6, the positions of the transfer head and the substrate are observed by the high-resolution positioning camera, the contact condition of the PDMS template and the substrate during the descending process of the Z-axis track 4 is observed by the high-resolution observation camera, and the pixel offset adjustment of the X / Y direction is realized by the bearing jig assembly 9, so as to realize the transfer of RGB three-color quantum dots.

[0094] ​The above merely describes some embodiments of the present application and does not limit the present application in any form. Although the present application is disclosed with the preferred embodiments, it is not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the disclosed technical contents without departing from the scope of the present application, and the equivalent embodiments are also included in the scope of the present application.

Claims

1. A method of fabricating a high-resolution full-color quantum dot light emitting diode, characterized in that, It comprises the following steps: S1: preparing a substrate and pretreating the substrate to ensure a clean and pollution-free surface; S2: spin coating a hole injection layer, spin coating a solution prepared from a hole injection layer material on the pretreated substrate and performing annealing treatment; S3: spin coating a hole transport layer, spin coating and depositing a solution prepared from a hole transport layer material on the surface of the hole injection layer to form an organic semiconductor thin film; S4: preparing a quantum dot light-emitting layer on the surface of the hole transport layer, comprising: processing first quantum dots, dissolving the first quantum dots in a first solvent to form a dense arrangement thin film on the liquid surface, sticking the thin film, using a positioning camera to complete pixel transfer after pixel alignment, and transferring the thin film to the substrate to form a first quantum dot matrix; processing second quantum dots, dissolving the second quantum dots in a second solvent to form a dense arrangement thin film on the liquid surface, sticking the thin film, using a positioning camera to complete pixel transfer after pixel alignment, and transferring the thin film to the substrate to form a second quantum dot matrix; processing third quantum dots, dissolving the third quantum dots in a third solvent to form a dense arrangement thin film on the liquid surface, sticking the thin film, using a positioning camera to complete pixel transfer after pixel alignment, and transferring the thin film to the substrate to form a third quantum dot matrix; the first quantum dots, the second quantum dots, and the third quantum dots are different in color; the first quantum dot matrix, the second quantum dot matrix, and the third quantum dot matrix are regularly arranged in the horizontal direction on the surface of the hole transport layer; S5: spin coating an electron transport layer, spin coating a solution prepared from an electron transport layer material on the surface of the quantum dot light-emitting layer and performing annealing treatment; S6: preparing a metal electrode; S7: packaging. 2.The method of claim 1, wherein the method further comprises: forming a first electrode layer on the substrate; forming a first quantum dot layer on the first electrode layer; forming a second quantum dot layer on the first quantum dot layer; and forming a second electrode layer on the second quantum dot layer. The pretreatment in step S1 comprises surface cleaning and treatment of the substrate; The material of the substrate is ITO glass. 3.The method of claim 1, wherein the method further comprises: forming a first electrode layer on the substrate; forming a first quantum dot layer on the first electrode layer; forming a second quantum dot layer on the first quantum dot layer; and forming a second electrode layer on the second quantum dot layer. The hole injection layer material in step S2 is selected from one of PEDOT:PSS, molybdenum oxide, nickel oxide, and cuprous thiocyanide; The thickness of the hole injection layer is 20-30 nm. 4.The method of claim 1, wherein the method further comprises: forming a first electrode layer on the substrate; forming a first quantum dot layer on the first electrode layer; forming a second quantum dot layer on the first quantum dot layer; and forming a second electrode layer on the second quantum dot layer. The hole transport layer material in step S3 is selected from one or a mixture of several of polymer TFB, cross-linked TFB, Poly:TPD, and PVK; The thickness of the hole transport layer is 40-50 nm. 5.The method of claim 1, wherein the method further comprises: forming a first electrode layer on the substrate; forming a first quantum dot layer on the first electrode layer; forming a second quantum dot layer on the first quantum dot layer; and forming a second electrode layer on the second quantum dot layer. The quantum dots in step S4 are light-emitting materials selected from one of cadmium quantum dots and indium phosphide quantum dots; The first solvent, the second solvent, and the third solvent in step S4 are independently selected from one of ethanol, diethyl ether, acetone, chloroform, and benzene; The thin film is stuck using a PDMS template. 6.The method of claim 1, wherein the method further comprises: forming a first electrode layer on the substrate; forming a first quantum dot layer on the first electrode layer; forming a second quantum dot layer on the first quantum dot layer; and forming a second electrode layer on the second quantum dot layer. The electron transport layer material in step S5 is selected from one of ZnO and zinc magnesium oxide; The thickness of the electron transport layer is 70-80 nm. 7.The method of claim 1, wherein the method further comprises: forming a first electrode layer on the substrate; forming a first quantum dot layer on the first electrode layer; forming a second quantum dot layer on the first quantum dot layer; and forming a second electrode layer on the second quantum dot layer. The metal electrode in step S6 is a silver electrode, and the preparation method specifically comprises: silver electrode evaporation on an evaporation machine; The thickness of the silver electrode is 90-100 nm.

8. The method for preparing a high-resolution full-color quantum dot light-emitting diode according to claim 1, characterized in that, Transparent material is used to package the device in step S7. The transparent material is selected from one of a polymer and a glass.

9. An apparatus for implementing the method of any one of claims 1-8 for fabricating high-resolution full-color quantum dot light-emitting diodes, characterized in that, A shock-absorbing platform is included; A motion assembly is arranged on the shock-absorbing platform, and a positioning camera assembly and an observation camera assembly are movably arranged on the motion assembly; A transfer head assembly is arranged near the positioning camera assembly; A film pulling machine and a carrier jig assembly are further arranged on the shock-absorbing platform.

10. The apparatus of claim 9, wherein, The motion assembly includes an X-axis rail, two ends of the X-axis rail are movably provided with double-drive Y-axis rails, and a Z-axis rail is movably arranged on the X-axis rail; The positioning camera assembly and the transfer head assembly are arranged on the Z-axis rail; The observation camera assembly is arranged on the double-drive Y-axis rail; The film pulling machine is arranged between the double-drive Y-axis rails.

Images