A direct photolithography method for preparing a QLED array device

Abstract

The application provides a direct photolithography preparation method of a QLED array device, and comprises the following steps: sequentially depositing a hole injection layer, a hole transport layer and a patterned light-emitting layer, an electron transport layer and a metal cathode on an ITO layer of a transparent conductive substrate. The patterned light-emitting layer is formed by blending a cross-linkable semiconductor polymer containing a photosensitizer and quantum dots to form ink, and is realized after spin coating, exposure and development. The application does not damage the surface ligand of the quantum dots, does not limit the type of quantum dots and the type of ligand, and is also beneficial to improving the hole transport capacity, so that a high-performance patterned QLED device is prepared.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of OLED display and relates to a direct photolithography method for preparing a QLED array device. BACKGROUND

[0002] At present, there are various quantum dot patterning methods, including photolithography, micro / nano imprinting, inkjet printing, x-ray lithography, electron beam lithography and the like. Among these technologies, photolithography technology is a most promising patterning method due to its mature process and easy realization of colorized pixel array. In recent years, many methods for preparing patterned light-emitting layers without photoresist based on photolithography process have emerged, such as ligand exchange, photocrosslinking and the like. Among them, ligand exchange leads to very low solubility, and new defect states easily appear on the surface of quantum dots, thereby resulting in poor device performance; photocrosslinking does not change the ligand distribution, but also does not directly contact the quantum dot core related to light emission, so the change in charge injection capacity is also small. This directly affects the implementation process of the patterned light-emitting layer and high-performance devices based on the photolithography process. SUMMARY

[0003] In view of the defects and deficiencies of the prior art, the application provides a direct photolithography method for preparing a QLED array device, which uses a cross-linkable semiconductor polymer and quantum dots to prepare ink, and realizes the preparation of a patterned light-emitting layer after the ink is subjected to spin coating, exposure and development processes. This method not only does not damage the ligand on the surface of the quantum dots, but also does not limit the type of quantum dots and ligand, and is also conducive to improving the performance of the device.

[0004] The scheme includes: sequentially depositing a hole injection layer, a hole transport layer and a patterned light-emitting layer, an electron transport layer and a metal cathode on an ITO layer of a transparent conductive substrate. The patterned light-emitting layer is realized by mixing a cross-linkable semiconductor polymer containing a photosensitizer and quantum dots to form ink, and then subjected to spin coating, exposure and development. The application not only does not damage the ligand on the surface of the quantum dots, but also does not limit the type of quantum dots and ligand, and is also conducive to improving the hole transport capacity, so as to prepare a high-performance patterned QLED device.

[0005] The technical scheme adopted by the application to solve the technical problems is:

[0006] A direct photolithography method for preparing a QLED array device, characterized in that:

[0007] The preparation process includes: sequentially depositing a hole injection layer, a hole transport layer and a patterned light-emitting layer, an electron transport layer and a metal cathode on an ITO layer of a transparent conductive substrate.

[0008] The specific process for preparing the patterned light-emitting layer is as follows:

[0009] Step S1: Pre-blend the cross-linkable semiconductor polymer A containing photosensitive additive and quantum dots B uniformly to obtain ink C;

[0010] Step S2: Spin-coat the ink C on the hole transport layer to form a film by using a film applicator;

[0011] Step S3: Cross-link the cross-linkable semiconductor polymer by mask exposure to form a stable light-emitting layer together with the quantum dots coated therein;

[0012] Step S4: Construct a patterned light-emitting layer by developing with n-octane.

[0013] Further, the cross-linkable polymer A is one of TFB, PVK, PFO, and PFSO.

[0014] Further, the photosensitive additive is one of benzoin dimethyl ether, benzophenone, and diphenyl ketone.

[0015] Further, the material of the quantum dots B is one of CdSe, InP, and halogen perovskite.

[0016] Further, the material of the hole injection layer is one of polymer PEDOT:PSS, molybdenum oxide, nickel oxide, and cuprous thiocyanate.

[0017] Further, the material of the hole transport layer is one of polymer TFB, Poly:TPD, PVK, and PTAA or a mixture of multiple thereof.

[0018] Further, the material of the electron transport layer is ZnMgO, ZnO nanoparticles, ZnO nanoparticles doped with metal cations, or a mixture of ZnO nanoparticles and a polymer.

[0019] Further, the material of the metal cathode is silver or aluminum.

[0020] Compared with the prior art, the present application and the preferred schemes thereof have the following beneficial effects:

[0021] (1) The cross-linkable semiconductor polymer containing photosensitive agent and quantum dots are blended in a certain proportion to prepare a patterned light-emitting layer, without affecting the charge injection and transport capacity of the quantum dot layer;

[0022] (2) No photoresist is used, avoiding the influence of photoresist residues on quantum dots;

[0023] (3) No damage to the surface ligand of quantum dots is involved, and high-performance patterned QLED devices are easily prepared;

[0024] (4) There is no limitation on the type of quantum dots and ligands, and it is universal;

[0025] (5) The preparation process is safe and pollution-free, no by-products are generated, and the process is simple and easy to operate. BRIEF DESCRIPTION OF DRAWINGS

[0026] The application will be described in further detail below with reference to the drawings and specific embodiments:

[0027] Figure 1 、 Figure 2 is a schematic diagram of a device structure formed by the preparation method of the embodiments of the application;

[0028] Figure 3 is a preparation flowchart of the patterned light-emitting layer of embodiment one, embodiment two and embodiment three. DETAILED DESCRIPTION

[0029] In order to make the features and advantages of the patent more obvious and easy to understand, the following specific examples are described in detail as follows:

[0030] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise indicated, all technical and scientific terms used in the specification have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0031] It should be noted that the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is intended to include the plural form, and in addition, it should be understood that when the terms "comprise" and / or "include" are used in the specification, they indicate the presence of a feature, step, operation, device, component and / or combination thereof.

[0032] Embodiment one

[0033] In this embodiment, reference is made to Figure 1 , specifically comprising the following steps:

[0034] 1) An ITO conductive film prepared by magnetron sputtering method is used as an anode substrate.

[0035] 2) The anode substrate is sequentially placed in a glass cleaning agent, deionized water, acetone, and ethanol for ultrasonic treatment, and the ultrasonic treatment time is 10 min each time.

[0036] 3) PEDOT:PSS is prepared by spin coating method as a hole injection layer, the annealing temperature is 120°C, and the thickness is about 30 nm.

[0037] 4) TFB is prepared by spin coating method as a hole transport layer, the annealing temperature is 120°C, and the thickness is about 40 nm.

[0038] 5) The ink is spin-coated on the surface of the hole transport layer as a patterned light-emitting layer with a thickness of about 30 nm. As shown in Figure 3 , it specifically includes the following steps: the cross-linkable polymer TFB containing a photosensitizer and red CdSe quantum dots are uniformly blended in a certain proportion in advance, a film is spin-coated by using a film applicator at a rotation speed of 2000 r and a time of 40 s, the cross-linkable polymer is cross-linked by mask exposure, and a patterned light-emitting layer is constructed by n-octane development.

[0039] 6) ZnO is prepared by spin coating as an electron transport layer, the annealing temperature is 80°C, and the thickness is about 50 nm.

[0040] 7) An Ag electrode is deposited by vacuum evaporation, and the thickness is 100 nm.

[0041] Example Two

[0042] In this embodiment, reference is made to Figure 1 , and it specifically includes the following steps:

[0043] 1) An ITO conductive film prepared by magnetron sputtering is used as an anode substrate.

[0044] 2) The anode substrate is sequentially placed in a glass cleaning agent, deionized water, acetone, and ethanol for ultrasonic treatment, and the ultrasonic treatment time is 10 min each time.

[0045] 3) PEDOT:PSS is prepared by spin coating as a hole injection layer, the annealing temperature is 120°C, and the thickness is about 30 nm.

[0046] 4) TFB is prepared by spin coating as a hole transport layer, the annealing temperature is 120°C, and the thickness is about 40 nm.

[0047] 5) The ink is spin-coated on the surface of the hole transport layer as a patterned light-emitting layer with a thickness of about 30 nm. As shown in Figure 3 , it specifically includes the following steps: the cross-linkable polymer TFB containing a photosensitizer and green InP quantum dots are uniformly blended in a certain proportion in advance, a film is spin-coated by using a film applicator at a rotation speed of 2000 r and a time of 40 s, the cross-linkable polymer is cross-linked by mask exposure, and a patterned light-emitting layer is constructed by n-octane development.

[0048] 6) ZnMgO is prepared by spin coating as an electron transport layer, the annealing temperature is 80°C, and the thickness is about 50 nm.

[0049] 7) An Al electrode is deposited by vacuum evaporation, and the thickness is 100 nm.

[0050] Example Three

[0051] In the present embodiment, reference is made to Figure 2 , specifically comprising the following steps:

[0052] 1) ITO conductive film prepared by magnetron sputtering method is used as anode substrate.

[0053] 2) The anode substrate is sequentially placed in glass cleaning agent, deionized water, acetone, ethanol for ultrasonic treatment, the ultrasonic time is 10 min each time.

[0054] 3) PEDOT:PSS is prepared by spin coating method as a hole injection layer, the annealing temperature is 120℃, and the thickness is about 30 nm.

[0055] 4) PTAA is prepared by spin coating method as a hole transport layer, the annealing temperature is 120℃, and the thickness is about 40 nm.

[0056] 5) Ink is spin-coated on the surface of the hole transport layer by spin coating method as a patterned light-emitting layer, and the thickness is about 30 nm. As shown in Figure 3 , specifically comprising the following steps: the cross-linkable polymer TFB containing photosensitizer and green light perovskite quantum dots are uniformly blended in a certain proportion, and are spin-coated into a film by using a film applicator at a rotation speed of 2000r and a time of 60s, the cross-linkable polymer is cross-linked by mask exposure, and the patterned light-emitting layer is constructed by n-octane development.

[0057] 6) TPBi is evaporated by vacuum evaporation method as an electron transport layer, and the thickness is 40 nm.

[0058] 7) Al / LiF is evaporated by vacuum evaporation method as a cathode, wherein the thickness of Al is 100 nm, and the thickness of LiF is 1 nm.

[0059] The above is only the preferred embodiment of the present application, and is not intended to limit the other forms of the present application. Any person skilled in the art can use the disclosed technical content to make changes or modifications as equivalent embodiments. However, any simple modification, equivalent change and modification made according to the technical essence of the present application to the above embodiments, without departing from the technical solution content of the present application, still belongs to the protection scope of the present application.

[0060] The present patent is not limited to the above best embodiment, and anyone can derive other various forms of a direct lithography method for preparing a QLED array device under the inspiration of the present patent. Any equivalent change and modification made according to the scope of the present patent application shall be covered by the present patent.

Claims

1. A direct photolithography method for preparing a QLED array device, characterized in that: the preparation process comprises sequentially depositing a hole injection layer, a hole transport layer, a patterned light-emitting layer, an electron transport layer, and a metal cathode on an ITO layer of a transparent conductive substrate; wherein the specific process for preparing the patterned light-emitting layer is as follows: Step S1: uniformly blend a cross-linkable semiconductor polymer A containing a photosensitive additive and quantum dots B in advance to obtain ink C; Step S2: spin-coat the ink C into a film on the hole transport layer using a film applicator at a rotation speed of 2000 r and for 60 s; Step S3: expose through a mask to cause the cross-linkable semiconductor polymer A to undergo cross-linking reaction and form a stable light-emitting layer together with the quantum dots B coated thereon; Step S4: develop the patterned light-emitting layer with n-octane; the cross-linkable semiconductor polymer A is one of TFB, PVK, PFO, and PFSO; the photosensitive additive is one of benzoin dimethyl ether, benzophenone, and diphenyl ketone; the material of the quantum dots B is halogen perovskite; the material of the hole injection layer is one of polymer PEDOT:PSS, molybdenum oxide, nickel oxide, and cuprous thiocyanate; the material of the hole transport layer is a mixture of one or more of polymer TFB, Poly-TPD, PVK, and PTAA.

2. The method of claim 1, wherein the method further comprises: depositing a first electrode layer on the substrate; depositing a first organic layer on the first electrode layer; depositing a second electrode layer on the first organic layer; and depositing a second organic layer on the second electrode layer. the material of the electron transport layer is ZnMgO, ZnO nanoparticles, ZnO nanoparticles doped with metal cations, or a mixture of ZnO nanoparticles and a polymer.

3. The method of claim 1, wherein the method further comprises: depositing a first electrode layer on the substrate; depositing a first organic layer on the first electrode layer; depositing a second electrode layer on the first organic layer; and depositing a second organic layer on the second electrode layer. the material of the metal cathode is silver or aluminum.

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