CN113193130A - Display panel and preparation method thereof - Google Patents

Display panel and preparation method thereof Download PDF

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Publication number
CN113193130A
CN113193130A CN202110360836.2A CN202110360836A CN113193130A CN 113193130 A CN113193130 A CN 113193130A CN 202110360836 A CN202110360836 A CN 202110360836A CN 113193130 A CN113193130 A CN 113193130A
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Prior art keywords
light
layer
emitting functional
emitting
buffer layer
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Chinese (zh)
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万之君
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Shenzhen China Star Optoelectronics Semiconductor Display Technology Co Ltd
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Shenzhen China Star Optoelectronics Semiconductor Display Technology Co Ltd
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Priority to CN202110360836.2A priority Critical patent/CN113193130A/en
Publication of CN113193130A publication Critical patent/CN113193130A/en
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    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K50/00—Organic light-emitting devices
    • H10K50/10—OLEDs or polymer light-emitting diodes [PLED]
    • H10K50/14—Carrier transporting layers
    • H10K50/16—Electron transporting layers
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/10—OLED displays
    • H10K59/12—Active-matrix OLED [AMOLED] displays
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H10K71/10—Deposition of organic active material
    • H10K71/12—Deposition of organic active material using liquid deposition, e.g. spin coating
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H10K71/10—Deposition of organic active material
    • H10K71/12—Deposition of organic active material using liquid deposition, e.g. spin coating
    • H10K71/13—Deposition of organic active material using liquid deposition, e.g. spin coating using printing techniques, e.g. ink-jet printing or screen printing
    • H10K71/135—Deposition of organic active material using liquid deposition, e.g. spin coating using printing techniques, e.g. ink-jet printing or screen printing using ink-jet printing
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K71/00—Manufacture or treatment specially adapted for the organic devices covered by this subclass
    • H10K71/10—Deposition of organic active material
    • H10K71/16—Deposition of organic active material using physical vapour deposition [PVD], e.g. vacuum deposition or sputtering
    • H10K71/164—Deposition of organic active material using physical vapour deposition [PVD], e.g. vacuum deposition or sputtering using vacuum deposition

Abstract

The embodiment of the application provides a display panel and a preparation method thereof, wherein the display panel comprises a substrate and a light-emitting functional layer; the light-emitting functional layer comprises a first light-emitting functional part and a second light-emitting functional part, and the second light-emitting functional part is arranged above the first light-emitting functional part; the display panel further comprises a buffer layer, the buffer layer is arranged between the first light-emitting functional part and the second light-emitting functional part, and the buffer layer is used for being damaged in an ion surface treatment process to protect the first light-emitting functional part. The embodiment of the application is used for preventing the damage to the part of the luminous function layer prepared in the ink-jet printing process when the substrate is subjected to plasma treatment before the other part of the luminous function layer is prepared in the subsequent evaporation process, and further ensuring the luminous performance of the display panel.

Description

Display panel and preparation method thereof
Technical Field
The application relates to the technical field of display, in particular to a display panel and a preparation method thereof.
Background
At present, mass production evaporation equipment generally adopts a Chuck (Chuck for bearing a substrate) logistics system. The method comprises the following steps of performing Chucking operation (operation of bonding a Chuck and a substrate) before the substrate enters an evaporation section to enable the Chuck to be attached to the substrate (back surface), then enabling the Chuck to bear the substrate to enable the substrate to be conveyed in a vacuum cavity of the evaporation section in a state that a film surface faces downwards, and reducing the warping amount of the substrate and being more suitable for an MMG (Multi-model Glass) technology by adopting a Chuck conveying mode.
The existing OLED (Organic Light Emitting Diode) panel is generally manufactured by an evaporation process, and before the Chucking, a TFT substrate (thin film transistor array substrate) is subjected to two-step pretreatment operation: step one (step1) is to place the substrate on a Stage using O2plasma (plasma process) is used for treating the surface of the substrate, so as to remove organic matters on the surface of the substrate and improve the work function of an anode; step two (step2) is to use Pin to jack up the substrate, using N2plasma simultaneously treats the film surface and the back surface of the substrate, so as to remove static electricity on the substrate, activate the surface of the TFT substrate (the back surface of the substrate) and enhance the adhesive force between the back surface of the substrate and the Chuck. Which is mainly through N2plasma processing the surface of the TFT substrate, removing static electricity and activating the surface of the TFT substrate so as to maintain stable operation of the chunk logistics.
In recent years, IJP (Ink Jet Printing) has attracted considerable attention from panel manufacturers because of its great potential to reduce the production cost of OLEDs, and it is possible to greatly reduce the production cost, making OLEDs more cost competitive in products including televisions and flat panel computers. For the IJPOLED panel, since the development of ETM (electron transport material) and EIM (electron injection material) inks is limited, an evaporation process (EV) is required for its fabrication. Therefore, when the IJPOLED panel is used to prepare the light-emitting functional layer, an inkjet printing process and an evaporation process must be performed in sequence.
When the IJP OLED panel is manufactured, in order to enable the TFT substrate and the Chuck to be bonded better and reduce the chip dropping rate in the transmission process, before the evaporation section Chucking is carried out, the substrate (back surface) needs to be subjected to Chucking pretreatment, and N is utilized2And plasma processing the back surface of the substrate, removing static electricity on the back surface of the substrate, activating the surface of the glass, and enhancing the adhesive force between the back surface of the substrate and the Chuck. However, in the chuking pretreatment, since the chuking operation substrate needs to be in a state of the upward film surface, the best state of the chuking pretreatment substrate is the upward film surface, while the plasma of the currently mature plasma processing equipment is generally generated from the upper part of the cavity, if the substrate is generatedThe film surface is upwards processed by plasma, and plasma can directly damage part of the luminous function layer prepared by the ink-jet printing process on the substrate, thereby affecting the performance of the final OLED device.
Therefore, in the fabrication process of the IJP OLED panel, how to avoid the damage to a part of the light emitting functional layer prepared by inkjet printing when the array substrate is subjected to plasma processing before the evaporation process, thereby affecting the performance of the final OLED device, is a technical problem that needs to be solved by those skilled in the art.
Disclosure of Invention
The embodiment of the application provides a display panel and a preparation method thereof, which can avoid damage to a part of light-emitting functional layers prepared by ink-jet printing caused by plasma treatment and ensure the display performance of an IJP OLED device.
The embodiment of the application provides a display panel, which comprises a substrate base plate and a light-emitting functional layer; the light-emitting functional layer comprises a first light-emitting functional part and a second light-emitting functional part, and the second light-emitting functional part is arranged above the first light-emitting functional part;
the display panel further comprises a buffer layer, the buffer layer is arranged between the first light-emitting functional part and the second light-emitting functional part and corresponds to the light-emitting area, and the buffer layer is used for being damaged in an ion surface treatment process to protect the first light-emitting functional part.
Optionally, in some embodiments of the present application, the material of the buffer layer includes an electron transport material.
Optionally, in some embodiments of the present application, the first light emitting functional portion includes a hole injection layer, a hole transport layer, and a light emitting material layer stacked from bottom to top; the second light-emitting functional part comprises an electron transport layer and an electron injection layer which are stacked from bottom to top, and the buffer layer and the electron transport layer are independently arranged layers.
Optionally, in some embodiments of the present application, a range of a work function of the buffer layer is between a work function of the light emitting material layer and a work function of the electron transport layer.
Optionally, in some embodiments of the present application, the buffer layer is prepared by a solution processing process, the first light-emitting functional portion is prepared by an inkjet printing process, and the second light-emitting functional portion is prepared by an evaporation process.
Optionally, in some embodiments of the present application, the buffer layer is an incomplete layer structure.
Correspondingly, the embodiment of the application also provides another display panel, which comprises a substrate and a light-emitting functional layer arranged on the substrate; the light-emitting functional layer comprises a first light-emitting functional part and a second light-emitting functional part, the second light-emitting functional part is arranged above the first light-emitting functional part, the first light-emitting functional part comprises a light-emitting material layer, and the second light-emitting functional layer comprises an electron transport layer positioned on the light-emitting material layer;
the display panel further comprises a buffer layer, the buffer layer is arranged between the light-emitting material layer of the first light-emitting function portion and the electron transmission layer of the second light-emitting function portion, the material of the buffer layer comprises an electron transmission material, and the buffer layer and the electron transmission layer of the second light-emitting function portion are independently arranged layers.
Correspondingly, an embodiment of the present application further provides a method for manufacturing the display panel, including the following steps:
s10, providing a substrate, wherein the substrate comprises a display area, and the display area comprises a plurality of light emitting areas;
s20, forming a first light-emitting functional part corresponding to each light-emitting area on the substrate through an ink-jet printing process;
s30, forming a buffer layer on the first light emitting functional part by a solution process;
s40, carrying out ion surface treatment process treatment on the substrate base plate;
and S50, forming a second light-emitting functional part on the whole upper surface of the substrate by vapor deposition, wherein the second light-emitting functional part completely covers the buffer layer and is in a whole surface communication state in the display area.
Optionally, in some embodiments of the present application, the material of the buffer layer includes an electron transport material.
Optionally, in some embodiments of the present application, in the S40, the ion surface treatment process is to remove at least a portion of the buffer layer.
According to the display panel and the preparation method thereof, the buffer layer is prepared on one part of the luminous functional layer prepared by the ink-jet printing process and used for preventing the part of the luminous functional layer prepared by the ink-jet printing process from being damaged when the substrate is subjected to plasma treatment before the other part of the luminous functional layer is prepared by the subsequent evaporation process, so that the luminous performance of the display panel is further ensured.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic diagram of a film structure of a display panel according to an embodiment of the present disclosure;
fig. 2 is a flowchart of a method for manufacturing a display panel according to an embodiment of the present disclosure;
fig. 3 is a schematic view illustrating a processing method of a display panel before an evaporation process according to an embodiment of the present disclosure.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
The embodiment of the application provides a display panel and a preparation method thereof. The following are detailed below. It should be noted that the following description of the embodiments is not intended to limit the preferred order of the embodiments. In addition, in the description of the present application, the term "including" means "including but not limited to". The terms first, second, third and the like are used merely as labels, and do not impose numerical requirements or an established order. Various embodiments of the invention may exist in a range of versions; it is to be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the invention; accordingly, the described range descriptions should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range. For example, it is contemplated that the description of a range from 1 to 6 has specifically disclosed sub-ranges such as, for example, from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as individual numbers within a range such as, for example, 1, 2, 3, 4, 5, and 6, as applicable regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any number (fractional or integer) recited within the indicated range.
The embodiment of the application aims at the technical problem that in the preparation process of an IJP OLED panel, when the array substrate is subjected to plasma treatment before an evaporation process, a part of a luminous functional layer prepared by ink-jet printing is damaged, so that the performance of a final OLED device is affected.
Referring to fig. 1, in which fig. 1 is a schematic diagram of a film structure of a display panel provided in an embodiment of the present application;
as shown in fig. 1, a display panel provided in an embodiment of the present application includes: a substrate 11, a plurality of first electrodes 12, a Pixel Defining Layer (PDL)13, a light emitting function layer (EL)14, and a second electrode 16; a buffer layer 15 is further provided in the light-emitting functional layer (EL) 14.
Specifically, the display panel includes a display region 101, and the display region 101 has a plurality of light emitting regions a and a plurality of non-light emitting regions N, which are disposed at intervals. Optionally, in some embodiments of the present application, the substrate 11 is a Thin Film Transistor (TFT) array substrate.
Specifically, the first electrode 12 is disposed on the substrate 11 and corresponds to the light emitting region a. Optionally, in some embodiments of the present application, the first electrode 12 is an anode, and the anode is electrically connected to the thin film transistor on the substrate 11 through a through hole.
Optionally, in some embodiments of the present application, the material of the first electrode 12 includes at least one of gold and silver.
Specifically, the pixel defining layer 13 is disposed on the substrate 11, the pixel defining layer 13 includes a pixel spacer 131 corresponding to each non-light emitting region N, and at least a portion of the first electrode 12 is exposed between two adjacent pixel spacers 131. That is, a pixel opening area is formed between two adjacent pixel spacers 131, and the anode is at least partially exposed in the pixel opening area to define a sub-pixel.
Further, in some embodiments of the present application, the pixel spacer 131 has a tilt angle (taper) β, wherein the tilt angle β is preferably in a range of 30 ° < β <60 °, so as to ensure that the formed film layer is not broken at the pixel spacer 131 when the light emitting function layer and the cathode are subsequently prepared on the pixel defining layer 13. On the premise that the film thickness of the pixel defining layer 13 and the panel aperture ratio are not changed, the smaller beta is, the more the formed film of the cathode is ensured not to be broken, i.e. cathode open circuit is not caused.
Specifically, the light-emitting function layer 14 is disposed on the pixel defining layer 13, the light-emitting function layer 14 includes a first light-emitting function portion 141 and a second light-emitting function portion 142, the first light-emitting function portion 141 is disposed on the substrate 11 and corresponds to the light-emitting area a, and the second light-emitting function portion 142 is disposed above the first light-emitting function portion 141 and is in a full-surface connected state in the display area 101.
Further, in some embodiments of the present application, the first light emitting function portion 141 is disposed on the first electrode 12, the buffer layer 15 is disposed on the first light emitting function portion 141, and the second light emitting function portion 142 is disposed on the pixel defining layer 13 and completely covers the buffer layer 15.
Specifically, the first light-emitting functional portion 141 is prepared by an inkjet printing process, the second light-emitting functional portion 142 is prepared by an evaporation process, and the buffer layer 15 is used for preventing the first light-emitting functional portion 141 from being damaged to protect the first light-emitting functional portion 141 when the substrate 11 is subjected to plasma treatment before the second light-emitting functional portion 142 is prepared. The reason is that when the ion surface treatment process is carried out, the organic film layer is always damaged by plasma treatment, and the organic film layer with any performance is damaged, but the damaged organic film layer has limited thickness; therefore, the buffer layer 15 is disposed on the first light emitting function portion 141 to replace damage of the organic film layer having a certain thickness. Further, in some embodiments of the present application, the first light emitting functional part 141 includes a Hole Injection Layer (HIL), a Hole Transport Layer (HTL), and a light Emitting Material Layer (EML), and the second light emitting functional part 142 includes an Electron Transport Layer (ETL) and an Electron Injection Layer (EIL); the light emitting principle of the OLED device is that a semiconductor material and an organic light emitting material emit light under the drive of an electric field through carrier injection and recombination.
Specifically, in an OLED device, generally, under a certain voltage, electrons and holes are injected into an electron transport layer and a hole transport layer from a cathode and an anode, respectively, and the electrons and the holes migrate to a light emitting material layer through the electron transport layer and the hole transport layer, respectively, and meet in the light emitting material layer to form excitons and excite light emitting molecules, which emit visible light through radiative relaxation.
Specifically, the second electrode 16 is disposed on the second light-emitting functional portion 142, and the second electrode 16 is in a full-surface connected state in the display region 101. Preferably, the second electrode 16 is a cathode, the material of the second electrode 16 is a transparent conductive metal Oxide, preferably Indium Tin Oxide (ITO), and the thickness of the second electrode 16 is preferably 20nm to 200 nm. According to the embodiment of the application, the second electrode 16 is in the whole-surface communication state between the light emitting area A corresponding to the sub-pixel and the non-light emitting area N between two adjacent rows of sub-pixels, so that the pixels can normally emit light, the light emitting uniformity of the display panel can be improved, and the display quality of the display panel, especially the full-color OLED display panel, is improved.
Specifically, the buffer layer 15 cannot be formed by evaporation, sputtering, or other processes, because these processes require a chunk stream method; the buffer layer 15 cannot be formed by a coating process, because the buffer layer 15 has a thin film thickness, the coating process cannot be satisfied; therefore, the buffer layer 15 needs to be formed by a solution process, such as spin coating, transfer printing, inkjet printing, and the like, and since the first light-emitting functional portion 141 is formed by an inkjet printing process, the buffer layer 15 is preferably formed by the inkjet printing process to simplify the process and reduce the cost.
Specifically, the electron transport layer is mainly used to enhance injection and transport of carriers from the second electrode 16.
Further, on the one hand, the buffer layer 15 is used for protecting the first light emitting function portion 141; on the other hand, since it is not ensured that the buffer layer 15 is removed at the time of plasma treatment, it is necessary to allow a small amount of the buffer layer 15 to remain in consideration of mass production feasibility, the buffer layer 15 must be made of an electron transport type material and its work function must match the light emitting material layer and the electron transport layer in upper and lower contact, and even if a small amount of the buffer layer 15 remains, the performance of the OLED device is not affected.
Among them, work function (work function), also called work function, is defined in solid physics as: the least energy required to move an electron from the interior of the solid to the surface of the object.
Preferably, the range of the work function of the buffer layer 15 is between the work function of the light emitting material layer and the work function of the electron transport layer.
Further, the buffer layer 15 has the same work function as that of the light emitting material layer or the electron transport layer.
Further, the material of the buffer layer 15 may theoretically be compatible with the electronsThe injection layer is made of the same material, but a solution-processable electron injection material is not currently used in mass production. Specifically, since the buffer layer 15 is located between the first light emitting function part 141 and the second light emitting function part 142, the presence of the buffer layer 15 may cause a performance degradation problem of the OLED device, and therefore, the material of the buffer layer 15 must be the same as that of the electron transport layer, and its work function must be matched with the light emitting material layer of the first light emitting function part 141 at the lower layer and the electron transport layer of the second light emitting function part 142 at the upper layer; the material of the electron transport layer needs solution processing to ensure that the buffer layer 15 can be formed into a film by adopting an ink-jet printing process, and the material can be selected from but not limited to ZnO and TiOx、WOx、NiO、NbyOxNano-particle suspension (formed by mixing nano-particles, dispersing agent and solvent) formed by nano-particles.
Wherein, the dispersing agent of the nano particle suspension generally comprises fatty acids, aliphatic amides, metal soaps, paraffin, low molecular wax and the like; the solvent of the nanoparticle suspension should satisfy the following conditions:
first, the nanoparticles can be dispersed;
second, the luminescent material layer cannot be dissolved;
thirdly, the boiling point cannot be too high, and the removal by vacuum drying and heating drying is convenient.
The solvent of the nanoparticle suspension is not limited in the variety on the basis of meeting the above conditions, and can be a pure solvent or a mixed solvent of multiple types.
Optionally, in some embodiments of the present application, the buffer layer 15 may be damaged during the ion surface treatment process; therefore, the buffer layer is an incomplete layer structure.
Correspondingly, the embodiment of the present application further provides a display panel, including:
a substrate base plate; and
the light-emitting functional layer is positioned on the substrate and comprises a first light-emitting functional part and a second light-emitting functional part, the second light-emitting functional part is arranged above the first light-emitting functional part, the first light-emitting functional part comprises a light-emitting material layer, and the second light-emitting functional layer comprises an electron transport layer positioned on the light-emitting material layer;
the display panel further comprises a buffer layer, the buffer layer is arranged between the light-emitting material layer of the first light-emitting function portion and the electron transmission layer of the second light-emitting function portion, the material of the buffer layer comprises an electron transmission material, and the buffer layer and the electron transmission layer of the second light-emitting function portion are independently arranged layers.
Fig. 2 and fig. 3 are also shown, in which fig. 2 is a flowchart of a method for manufacturing a display panel according to an embodiment of the present disclosure, and fig. 3 is a schematic view of a processing method of the display panel according to the embodiment of the present disclosure before an evaporation process.
As shown in fig. 2 and with reference to fig. 1, a method for manufacturing a display panel provided in an embodiment of the present application includes the following steps:
s10, providing a substrate 11, where the substrate 11 includes a display area 101, and the display area includes a plurality of light emitting areas.
Specifically, the S10 further includes:
firstly, a substrate 11 is provided, the substrate 11 includes a display region 101, the display region 101 has a plurality of light emitting regions a and a plurality of non-light emitting regions N, and the light emitting regions a and the non-light emitting regions N are arranged at intervals. Optionally, in some embodiments of the present application, the substrate 11 is a Thin Film Transistor (TFT) array substrate.
S20, forming a first light emitting function portion 141 on the substrate 11 corresponding to each of the light emitting areas a by an inkjet printing process.
Specifically, the S20 further includes:
firstly, forming a first electrode 12 on the substrate 11 corresponding to each light-emitting area a, wherein the first electrode 12 serves as an anode of the display panel, the first electrode 12 is an anode, and the anode is electrically connected with the thin film transistor on the substrate 11 through a through hole; optionally, in some embodiments of the present application, the material of the first electrode 12 includes at least one of gold and silver.
Next, a pixel defining layer 13 is formed on the substrate 11, the pixel defining layer 13 includes a pixel spacing portion 131 corresponding to each non-light emitting region N, at least a portion of the first electrode 12 is exposed between two adjacent pixel spacing portions 131, that is, a pixel opening region is formed between two adjacent pixel spacing portions 131, and at least a portion of the first electrode 12 is exposed in the pixel opening region, so as to define a sub-pixel.
Further, in some embodiments of the present application, the pixel spacer 131 has a tilt angle (taper) β, wherein the tilt angle β is preferably in a range of 30 ° < β <60 °, so as to ensure that the formed film layer is not broken at the pixel spacer 131 when the light emitting function layer and the cathode are subsequently prepared on the pixel defining layer 13. On the premise that the film thickness of the pixel defining layer 13 and the panel aperture ratio are not changed, the smaller beta is, the more the formed film of the cathode is ensured not to be broken, i.e. cathode open circuit is not caused.
Finally, a first light emitting function portion 141 is formed on the substrate 11 corresponding to each of the light emitting regions a through an inkjet printing process, the first light emitting function portion 141 is disposed on the first electrode 12, and the first light emitting function portion 141 includes a Hole Injection Layer (HIL), a Hole Transport Layer (HTL), and a light Emitting Material Layer (EML).
S30, a buffer layer 15 is formed on the first light emitting function part 141 through a solution process.
Specifically, the S30 further includes:
a buffer layer 15 is formed on the first light emitting function portion 141 through a solution process. The buffer layer 15 cannot be formed by processes such as evaporation, sputtering and the like, because these processes need a chunk logistics mode; the buffer layer 15 cannot be formed by a coating process, because the buffer layer 15 has a thin film thickness, the coating process cannot be satisfied; therefore, the buffer layer 15 needs to be formed by a solution process, such as spin coating, transfer printing, inkjet printing, and the like, and since the first light-emitting functional portion 141 is formed by an inkjet printing process, the buffer layer 15 is preferably formed by the inkjet printing process to simplify the process and reduce the cost.
Specifically, the material of the buffer layer 15 must be the same as the material of the electron transport layer, and its work function must match the lower layer of the luminescent material layer of the first luminescent functional part 141 and the upper layer of the electron transport layer of the second luminescent functional part 142; the material of the electron transport layer needs solution processing to ensure that the buffer layer 15 can be formed into a film by adopting an ink-jet printing process, and the material can be selected from but not limited to ZnO and TiOx、WOx、NiO、NbyOxAnd (3) waiting for the nanoparticle suspension (formed by mixing nanoparticles, a dispersing agent and a solvent).
S40, the substrate 11 is subjected to an ion surface treatment process.
Specifically, the S40 further includes:
after the buffer layer 15 is formed on the first light-emitting functional portion 141, in order to better adhere the substrate 11 to the Chuck and reduce the chip dropping rate in the transmission process, a Chucking pretreatment process needs to be performed on the substrate (back surface) before proceeding to the vapor deposition process stage Chucking; wherein the ion surface treatment process causes at least a portion of the buffer layer 15 to be removed. S50, forming a second light emitting function portion 142 by vapor deposition over the entire surface of the substrate 11, wherein the second light emitting function portion 142 completely covers the buffer layer 15 and is in a state of being connected to the entire surface of the display region 101.
Specifically, the S50 further includes:
because the development of the ink of the electron transport layer and the electron injection layer is limited, currently, in the process of preparing the OLED display device, only the first light-emitting functional portion 141 can be prepared by using an inkjet printing process, and only an evaporation process can be used for preparing the subsequent second light-emitting functional portion 142.
At present, mass production evaporation equipment generally adopts a chunk logistics system. The Chuck is used for bearing the substrate, the Chucking operation (the operation of bonding the Chuck and the substrate) is carried out before the substrate enters the evaporation section, so that the Chuck is attached to the substrate (the back surface), then the Chuck can bear the substrate, and the substrate is conveyed in a vacuum cavity of the evaporation section in a face down state, the warpage of the substrate can be reduced by adopting a Chuck conveying mode, and the Chuck conveying mode is more suitable for the MMG technology.
As shown in fig. 3, which is a schematic view of a processing method of a display panel before an evaporation process according to an embodiment of the present application, a chuking pre-processing process includes the following specific steps:
firstly, the substrate 11 on which the first light-emitting functional part 141 and the buffer layer 15 are prepared is transported into a plasma processing chamber 21 through a chunk logistics system; then, the substrate 11 is placed on a Stage 23(Stage), and the substrate 11 is lifted up by a top Pin 231(Pin) on the Stage 23; thereafter, N is discharged through a diffuser 22 (diffuser) at an upper portion in the plasma processing chamber 212Using N2The plasma treatment process 24 simultaneously treats the film surface and the back surface of the substrate 11 in order to remove static electricity on the substrate 11, activate the surface (back surface) of the substrate 11, and enhance the adhesive force between the back surface of the substrate 11 and Chuck. Which is mainly through N2And (3) carrying out plasma treatment on the surface of the substrate base plate 11, removing static electricity and activating the surface of the substrate base plate 11 so as to maintain stable operation of the chunk logistics.
Specifically, since the material of the buffer layer 15 is the same as that of the electron transport layer, the buffer layer 15 can prevent N2The plasma treatment damages the first light emitting function portion 141, thereby ensuring the light emitting performance of the final display panel.
Further, the thickness of the buffer layer 15 is equal to the thickness of the N2The processing intensity of the plasma processing is matched. The N is generally determined by static quantity test of the back surface of the substrate 11 after the Chucking pretreatment process and statistics of the transportation chip-dropping rate of the substrate 112The processing intensity of the plasma processing is confirmed based on the above2The degree of damage to the buffer layer 15 by the plasma treatment, the thickness of the buffer layer 15 being set on the basis that the buffer layer 15 is substantially completely damaged even if the buffer layer 15 remains because it is made of an electron transporting material to have electricityAnd the sub-transmission function is added into the IJP OLED device, so that the carrier balance of the device is not influenced, the structure of the device is matched, and the performance of the device is ensured.
Then, after the chuking pretreatment process is completed, performing a chuking process on the substrate 11, wherein the chuking process is used for bonding the Chuck and the substrate 11; after the substrate base plate 11 is subjected to the chuking pretreatment process, the adhesive force between the back surface of the substrate base plate 11 and the Chuck is enhanced, so that the wafer falling purpose of the substrate base plate 11 in the chuking process can be effectively reduced.
Then, after the chuking process is completed, a second light-emitting functional portion 142 is formed on the entire surface of the substrate 11 by an evaporation process, and the second light-emitting functional portion 142 completely covers the buffer layer 15 and is in a full-surface connection state in the display region 101. Wherein the first light-emitting functional portion 141 and the second light-emitting functional portion 142 constitute a light-emitting functional layer 14 of the display panel; the second light emitting functional part 142 includes an Electron Transport Layer (ETL) and an Electron Injection Layer (EIL); the electron transport layer is mainly used to enhance the injection and transport of carriers from the second electrode 16, and the material of the electron transport layer can be selected from but not limited to ZnO and TiOx、WOx、NiO、NbyOxAnd (3) waiting for the nanoparticle suspension (formed by mixing nanoparticles, a dispersing agent and a solvent).
Finally, after the second light-emitting functional section 142 is completely vapor-deposited, the second electrode 16 is continuously vapor-deposited on the second light-emitting functional section 142, and the second electrode 16 is in a state of being connected over the entire surface of the display region 101. Preferably, the second electrode 16 is a cathode, the material of the second electrode 16 is a transparent conductive metal oxide, preferably indium tin oxide, and the thickness of the second electrode 16 is preferably 20nm to 200 nm. According to the embodiment of the application, the second electrode 16 is in the whole-surface communication state between the light emitting area A corresponding to the sub-pixel and the non-light emitting area N between two adjacent rows of sub-pixels, so that the pixels can normally emit light, the light emitting uniformity of the display panel can be improved, and the display quality of the display panel, especially the full-color OLED display panel, is improved.
Due to the current mature plasmaDiffusers in sub-processing apparatus are typically disposed above the chamber, if it is desired to avoid the N2If the first light-emitting functional portion 141 on the substrate 11 is damaged by the strong processing area of the plasma processing, the substrate 11 needs to be turned over and then enter a cavity to perform the N process2However, since the chuking process needs to be performed in a state where the film surface of the substrate 11 is facing upward, if the first light-emitting function portion 141 is prevented from being damaged by this method, it is necessary to add a turning device before and after the chuking pretreatment process, which increases the cost of the device and complicates the process flow.
Therefore, the preparation method of the display panel does not need to add overturning equipment, reduces equipment cost and is simpler in process flow.
The method for manufacturing the display panel provided by the embodiment of the application utilizes N in the Chucking pretreatment process2The TFT substrate is subjected to plasma processing, so that the purposes of enhancing the adhesive force between the back of the TFT substrate and a chuck and reducing the chip falling rate of the TFT substrate in a chuking process are achieved, meanwhile, the damage of the plasma processing technology to a part of light-emitting functional layers prepared through an ink-jet printing layer can be avoided, and the performance of the IJP OLED device is further ensured.
In summary, according to the display panel and the manufacturing method thereof provided by the embodiment of the application, the buffer layer is prepared on a part of the light emitting functional layer prepared by the inkjet printing process, so that when the substrate is subjected to plasma chemical treatment before another part of the light emitting functional layer is prepared by the subsequent evaporation process, the part of the light emitting functional layer prepared by the inkjet printing process is damaged, and the light emitting performance of the display panel is further ensured.
In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
The display panel and the manufacturing method thereof provided by the embodiments of the present application are described in detail above, and the principle and the embodiment of the present application are explained herein by applying specific examples, and the description of the embodiments above is only used to help understanding the method and the core idea of the present application; meanwhile, for those skilled in the art, according to the idea of the present application, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present application.

Claims (10)

1. A display panel, comprising:
a substrate base plate; and
the light-emitting functional layer is positioned on the substrate and comprises a first light-emitting functional part and a second light-emitting functional part, and the second light-emitting functional part is arranged above the first light-emitting functional part;
the display panel further comprises a buffer layer, the buffer layer is arranged between the first light-emitting functional part and the second light-emitting functional part, and the buffer layer is used for being damaged in an ion surface treatment process to protect the first light-emitting functional part.
2. The display panel according to claim 1, wherein a material of the buffer layer comprises an electron transport material.
3. The display panel according to claim 2, wherein the first light-emitting functional portion comprises a hole injection layer, a hole transport layer, and a light-emitting material layer which are stacked from bottom to top; the second light-emitting functional part comprises an electron transport layer and an electron injection layer which are stacked from bottom to top, and the buffer layer and the electron transport layer are independently arranged layers.
4. The display panel according to claim 3, wherein a range of values of a work function of the buffer layer is between a work function of the light emitting material layer and a work function of the electron transport layer.
5. The display panel according to claim 1, wherein the buffer layer is prepared by a solution processing process, the first light-emitting functional portion is prepared by an inkjet printing process, and the second light-emitting functional portion is prepared by an evaporation process.
6. The display panel according to claim 1, wherein the buffer layer has an non-integral layer structure.
7. A display panel, comprising:
a substrate base plate; and
the light-emitting functional layer is positioned on the substrate and comprises a first light-emitting functional part and a second light-emitting functional part, the second light-emitting functional part is arranged above the first light-emitting functional part, the first light-emitting functional part comprises a light-emitting material layer, and the second light-emitting functional part comprises an electron transport layer positioned on the light-emitting material layer;
the display panel further comprises a buffer layer, the buffer layer is arranged between the light-emitting material layer of the first light-emitting function portion and the electron transmission layer of the second light-emitting function portion, the material of the buffer layer comprises an electron transmission material, and the buffer layer and the electron transmission layer of the second light-emitting function portion are independently arranged layers.
8. A method of manufacturing a display panel according to any one of claims 1 to 7, comprising the steps of:
s10, providing a substrate, wherein the substrate comprises a display area, and the display area comprises a plurality of light emitting areas;
s20, forming a first light-emitting functional part corresponding to each light-emitting area on the substrate through an ink-jet printing process;
s30, forming a buffer layer on the first light emitting functional part by a solution process;
s40, carrying out ion surface treatment process treatment on the substrate base plate;
and S50, forming a second light-emitting functional part on the whole upper surface of the substrate by vapor deposition, wherein the second light-emitting functional part completely covers the buffer layer and is in a whole surface communication state in the display area.
9. The method according to claim 8, wherein a material of the buffer layer comprises an electron transport material.
10. The method of claim 8, wherein in the step S40, the ion surface treatment process is performed to remove at least a portion of the buffer layer.
CN202110360836.2A 2021-04-02 2021-04-02 Display panel and preparation method thereof Pending CN113193130A (en)

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Citations (5)

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US20170033169A1 (en) * 2015-07-28 2017-02-02 Samsung Display Co., Ltd. Organic light emitting diode and organic light emitting diode display including the same
CN106816545A (en) * 2017-03-23 2017-06-09 京东方科技集团股份有限公司 Light emitting diode with quantum dots and preparation method thereof, array base palte, display device
CN109075253A (en) * 2016-03-04 2018-12-21 太阳视窗技术公司 System and method for having the organic semiconductor device of sputtering contact layer
CN110690352A (en) * 2019-09-06 2020-01-14 深圳市华星光电半导体显示技术有限公司 Display panel and preparation method thereof
CN111029475A (en) * 2019-11-25 2020-04-17 深圳市华星光电半导体显示技术有限公司 Display and preparation method thereof

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Publication number Priority date Publication date Assignee Title
US20170033169A1 (en) * 2015-07-28 2017-02-02 Samsung Display Co., Ltd. Organic light emitting diode and organic light emitting diode display including the same
CN109075253A (en) * 2016-03-04 2018-12-21 太阳视窗技术公司 System and method for having the organic semiconductor device of sputtering contact layer
CN106816545A (en) * 2017-03-23 2017-06-09 京东方科技集团股份有限公司 Light emitting diode with quantum dots and preparation method thereof, array base palte, display device
CN110690352A (en) * 2019-09-06 2020-01-14 深圳市华星光电半导体显示技术有限公司 Display panel and preparation method thereof
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