Light emitting substrate, method of manufacturing the same and light emitting device

Abstract

The application relates to the technical field of display, in particular to a light-emitting substrate, a preparation method thereof and a light-emitting device. The application aims at solving the problems of light-emitting crosstalk between adjacent light-emitting units caused by full-area coverage of an intermediate connecting layer and the problem of pixel opening characteristic being damaged by the full-area coverage of the intermediate connecting layer, which is not conducive to printing of the upper light-emitting unit. A preparation method of a light-emitting substrate comprises the following steps: forming a pixel defining layer on a substrate, the pixel defining layer having a plurality of openings; forming a first light-emitting unit in at least one opening; forming a temporary shielding layer in a region not covered by the first light-emitting unit, the temporary shielding layer being used for shielding a region of the pixel defining layer not covered by the first light-emitting unit; forming an intermediate connecting layer in a region where the first light-emitting unit is located; and evaporating to remove the temporary shielding layer.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to a light-emitting substrate, a method for preparing the substrate, and a light-emitting device. Background Technology

[0002] Multilayer light-emitting devices (MLDs) combine two light-emitting units in series in a direction perpendicular to the substrate, thereby doubling the efficiency and brightness under the same current. The key to fabricating MLDs is the intermediate connecting layer, which is currently only fabricated industrially using vacuum evaporation or sputtering methods.

[0003] Currently, vacuum-prepared intermediate connecting layers are suitable for light-emitting units prepared by vacuum evaporation, but not for light-emitting units prepared by IJP printing. The main reason is that the intermediate connecting layer prepared by vacuum is a full-surface covering. On the one hand, this full-surface covering intermediate connecting layer often increases the conductivity in the lateral direction, leading to light emission crosstalk between adjacent light-emitting units, thus affecting the light emission effect of the entire light-emitting substrate. On the other hand, this full-surface covering intermediate connecting layer covers the pixel openings and part of the sidewalls of the pixel openings, causing the original hydrophobic properties between the pixel openings and the hydrophilic properties of the sidewalls of the pixel openings to be lost, which is not conducive to the preparation of light-emitting units on the upper layer of the intermediate connecting layer by inkjet printing. Summary of the Invention

[0004] Based on this, this application provides a light-emitting substrate, its preparation method, and a light-emitting device to solve the problem of light emission crosstalk between adjacent light-emitting units caused by the full coverage of the intermediate connecting layer in the related art, as well as the problem that the full coverage of the intermediate connecting layer destroys the pixel opening characteristics and is not conducive to the printing of the upper light-emitting units.

[0005] In a first aspect, a method for preparing a light-emitting substrate is provided, comprising:

[0006] A pixel defining layer is formed on a substrate, the pixel defining layer having multiple openings;

[0007] A first light-emitting unit is formed in at least one of the openings;

[0008] A temporary shielding layer is formed in the area not covered by the first light-emitting unit, and the temporary shielding layer is used to shield the area of ​​the pixel boundary layer not covered by the first light-emitting unit;

[0009] The intermediate connection layer is formed in the region where the first light-emitting unit is located;

[0010] Evaporation is used to remove the temporary shielding layer.

[0011] Optionally, the adhesion coefficient between the material of the temporary shielding layer and the material of the intermediate connecting layer is less than 0.1.

[0012] Optionally, the temporary shielding layer may be made of organic materials; the intermediate connecting layer may be made of inorganic materials.

[0013] Optionally, the temporary shielding layer is made of a fluorinated organic compound with a molecular weight of less than 1000; and / or,

[0014] The intermediate connecting layer is made of metal or metal oxide.

[0015] Optionally, the material for the temporary shielding layer includes any one of the following compounds:

[0016]

[0017] In compound (I), Ar1, Ar2, and Ar3 are independently selected from substituted or unsubstituted aryl groups having 6 to 50 carbon atoms and heteroaryl groups having 4 to 50 carbon atoms, respectively; the substituents in Ar1, Ar2, and Ar3 are selected from one or more of deuterium, fluorine, chlorine, C1 to C6 alkyl, cycloalkyl, silyl, fluoroalkyl, arylalkyl, aryl, haloaryl, heteroaryl, alkoxy, haloalkoxy, fluoroalkoxy, fluoroaryl, and trifluoroaryl, and at least one substituent is fluorine, fluoroalkyl, fluoroalkoxy, fluoroaryl, or trifluoroaryl; Ar1 ​​is 0 to 2; and / or,

[0018] The metal is at least one of Ag, Al, Yb and Ce, and the metal oxide is at least one of IZO, ITO, ZnO, IGZO and ITZO.

[0019] Optionally, the material of the temporary shielding layer is selected from one or more of the following compounds:

[0020]

[0021]

[0022] In the above structural formula, B1, B2, B4, B5, B6, B7, B8, Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8, B'1, B'2, B'3, B'4, B'5, B'6 and B'8 are each independently selected from one or more of deuterium, fluorine, chlorine, C1-C6 alkyl, cycloalkyl, silyl, fluoroalkyl, arylalkyl, aryl, haloaryl, heteroaryl, alkoxy, haloalkoxy, fluoroalkoxy, fluoroaryl and trifluoroaryl.

[0023] In some embodiments, B1, B2, B4, B5, B6, B7, B8, Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8, B'1, B'2, B'3, B'4, B'5, B'6, and B'8 are each independently selected from: methyl, methoxy, ethyl, tert-butyl, fluoromethyl, difluoromethyl, trifluoromethyl, fluoroalkoxy, difluoromethoxy, trifluoromethoxy, fluoroethyl, polyfluoroethyl, 4-fluorophenyl, 3,4,5-trifluorophenyl, and 4-(trifluoromethoxy)phenyl.

[0024] Optionally, at least one of Z3 and Z7 is 3,4,5-trifluorophenyl.

[0025] Optionally, at least one of B1, B2, B4, B5, B6, B7, B8, B'1, B'2, B'3, B'4, B'5, B'6 and B'8 is trifluoromethyl.

[0026] Optionally, at least one of A1, A2, A3, A4, A5, A'1, A'2, A'4, A'5 and A'6 is fluorine.

[0027] Optionally, the fluorinated organic compound is selected from one or more of the following compounds:

[0028]

[0029]

[0030] Optionally, in the step of evaporating and removing the temporary shielding layer, the vacuum degree of evaporation is less than 10. -5 Torr, with a temperature of 100–250℃.

[0031] Optionally, the step of forming a temporary shielding layer in the area not covered by the first light-emitting unit includes:

[0032] A metal mask is used to shield the area where the first light-emitting unit is located, and a temporary shielding layer is formed in the area not covered by the first light-emitting unit by vapor deposition.

[0033] Optionally, it also includes: forming a second light-emitting unit in at least one opening in which the intermediate connecting layer is formed by printing;

[0034] Electrodes are formed in the region where the second light-emitting unit is located by vapor deposition.

[0035] Optionally, the intermediate connecting layer can be formed in the region where the first light-emitting unit is located by vapor deposition or sputtering.

[0036] Secondly, a light-emitting substrate is provided, comprising:

[0037] Substrate;

[0038] A pixel defining layer is disposed on the substrate, the pixel defining layer having a plurality of openings; and

[0039] A first light-emitting unit, an intermediate connecting layer, and a second light-emitting unit are sequentially stacked within the opening, with the first light-emitting unit being close to the substrate.

[0040] Optionally, the intermediate connecting layer is prepared by the following method:

[0041] A first light-emitting unit is formed in at least one opening;

[0042] A temporary shielding layer is formed in the area not covered by the first light-emitting unit, and the temporary shielding layer is used to shield the area of ​​the pixel boundary layer not covered by the first light-emitting unit;

[0043] The intermediate connection layer is formed in the region where the first light-emitting unit is located;

[0044] Evaporation is used to remove the temporary shielding layer.

[0045] Optionally, it also includes: electrodes disposed on the surface of at least one second light-emitting unit.

[0046] Optionally, the second light-emitting unit is in direct contact with the sidewall of the opening in which it is located.

[0047] Thirdly, a light-emitting device is provided, comprising:

[0048] The light-emitting substrate as described in the second aspect.

[0049] Compared with the prior art, this application has the following beneficial effects:

[0050] By forming a temporary shielding layer in the area not covered by the first light-emitting unit, the temporary shielding layer can prevent the intermediate connecting layer from forming in the area not covered by the first light-emitting unit. After the intermediate connecting layer is formed in the area where the first light-emitting unit is located, the temporary shielding layer can be removed to temporarily shield and protect the area not covered by the first light-emitting unit. In this way, on the one hand, the intermediate connecting layer can be formed in the area where the first light-emitting unit is located without affecting the connection between the intermediate connecting layer and the light-emitting unit above the intermediate connecting layer. On the other hand, it can prevent the intermediate connecting layer from covering the entire surface, thereby solving the problem of light emission crosstalk between adjacent light-emitting units caused by the full coverage of the intermediate connecting layer in related technologies, as well as the problem of failure of the hydrophobic properties between pixel openings and the hydrophilic properties of the sidewalls of pixel openings. As a result, inkjet printing can be used to fabricate light-emitting devices on a single-layer pixel opening, simplifying the fabrication process and device structure.

[0051] In addition, compared with the method of using solvent to dissolve the temporary masking layer in related technologies to remove the temporary masking layer, the method of removing it by evaporation does not introduce any solvent, thereby further reducing the damage to the hydrophilic and hydrophobic properties of the pixel opening and reducing the damage to the underlying light-emitting unit. Attached Figure Description

[0052] Figure 1 A schematic flowchart illustrating a method for fabricating a light-emitting substrate according to an embodiment of this application;

[0053] Figure 2 This is a cross-sectional structural diagram showing the location of the second light-emitting unit provided in an embodiment of this application. Detailed Implementation

[0054] The present application will be further described in detail below with reference to specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0055] Unless otherwise defined, 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 belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0056] Based on the above technical problems, some embodiments of this application provide a method for preparing a light-emitting substrate, such as... Figure 1 As shown, it includes:

[0057] S11. A pixel defining layer 20 is formed on the substrate 10, and the pixel defining layer 20 has a plurality of openings K;

[0058] The substrate 10 can be a TFT substrate, and the base layer of the TFT substrate can be a flexible material (such as IP) or a rigid material (such as glass). A first electrode, such as an anode ITO, is also formed on the substrate 10.

[0059] A hydrophobic layer can be formed on the surface of the pixel defining layer 20, and a hydrophilic layer can be formed on the sidewall of each opening K. In this way, through the combined action of the hydrophobic layer between the openings K and the hydrophilic layer on the sidewall of the opening K, the ink printed outside the opening K can flow into the opening K under capillary action.

[0060] S12. A first light-emitting unit 30 is formed in at least one opening K.

[0061] The first light-emitting unit 30 can be any light-emitting unit of any color. The first light-emitting unit 30 may include: a light-emitting layer, and at least one of a hole transport layer, a hole injection layer, an electron transport layer, an electron injection layer, a hole blocking layer, and an electron blocking layer.

[0062] S13. A temporary masking layer 100 is formed in the area not covered by the first light-emitting unit 30. The temporary masking layer 100 is used to mask the area of ​​the pixel boundary layer not covered by the first light-emitting unit 30.

[0063] S14. An intermediate connecting layer 40 is formed in the region where the first light-emitting unit 30 is located.

[0064] For example, the intermediate connecting layer 40 can be formed by vapor deposition or sputtering.

[0065] S15. Evaporate to remove the temporary shielding layer 100.

[0066] In the method for preparing a light-emitting substrate provided in this application embodiment, a temporary shielding layer 100 is formed in the area of ​​the pixel defining layer not covered by the first light-emitting unit 30. The temporary shielding layer 100 can prevent the intermediate connecting layer 40 from forming in the area not covered by the first light-emitting unit 30. After the intermediate connecting layer 40 is formed in the area where the first light-emitting unit 30 is located, the temporary shielding layer 100 is removed by evaporation, which can temporarily shield and protect the area not covered by the first light-emitting unit 30. In this way, on the one hand, the intermediate connecting layer 40 can be formed in the area where the first light-emitting unit 30 is located without affecting the connection between the intermediate connecting layer 40 and the light-emitting unit above the first light-emitting unit 30. On the other hand, it can prevent the intermediate connecting layer 40 from covering the entire surface, thereby solving the problem of light emission crosstalk between adjacent light-emitting units caused by the full coverage of the intermediate connecting layer 40 in the related technology, as well as the problem of the failure of the original hydrophobic properties between the pixel openings and the original hydrophilic properties of the pixel opening sidewalls in the related technology. Thus, inkjet printing can be used to prepare light-emitting devices.

[0067] In addition, compared with the method of removing the temporary masking layer 100 by dissolving it with a solvent in related technologies, the method of removing it by evaporation does not introduce any solvent, thereby further reducing the damage to the hydrophilic and hydrophobic properties of the pixel opening and reducing the damage to the underlying light-emitting unit.

[0068] In some embodiments, the adhesion coefficient between the material of the temporary shielding layer 100 and the material of the intermediate connecting layer 40 is less than 0.1.

[0069] At a given surface coverage, the net adsorption rate of molecules divided by the collision rate between molecules and the surface is called the adhesion coefficient.

[0070] In these embodiments, by controlling the adhesion coefficient between the material of the temporary shielding layer 100 and the material of the intermediate connecting layer 40 to be less than 0.1, when the intermediate connecting layer 40 is formed, the material of the intermediate connecting layer 40 will not or will adhere very little to the temporary shielding layer 100. Thus, when the temporary shielding layer 100 is subsequently removed by evaporation, the temporary shielding layer 100 can be completely removed.

[0071] In some embodiments, the material of the temporary shielding layer includes organic materials; the material of the intermediate connecting layer includes inorganic materials.

[0072] In these embodiments, by using organic materials as the material of the temporary shielding layer 100 and inorganic materials as the intermediate connecting layer 40, the adhesion of the material of the intermediate connecting layer 40 to the temporary shielding layer 100 can be further reduced.

[0073] In some embodiments, the temporary shielding layer 100 is made of a fluorinated organic compound with a molecular weight of less than 1000; and / or, the intermediate connecting layer is made of a metal or a metal oxide.

[0074] In these embodiments, the temporary shielding layer 100 is made of a fluorinated organic compound, which effectively reduces the adhesion of the intermediate connecting layer 40 material to the temporary shielding layer 100. Furthermore, by limiting the molecular weight of the fluorinated compound to less than 1000, the evaporation temperature can be effectively reduced, thereby facilitating the evaporation and removal of the temporary shielding layer.

[0075] In some embodiments, the material of the temporary shielding layer includes any one of the following compounds:

[0076]

[0077] In compound (I), Ar1, Ar2, and Ar3 are independently selected from substituted or unsubstituted aryl groups having 6 to 50 carbon atoms and heteroaryl groups having 4 to 50 carbon atoms, respectively; the substituents in Ar1, Ar2, and Ar3 are selected from one or more of deuterium, fluorine, chlorine, C1 to C6 alkyl, cycloalkyl, silyl, fluoroalkyl, arylalkyl, aryl, haloaryl, heteroaryl, alkoxy, haloalkoxy, fluoroalkoxy, fluoroaryl, and trifluoroaryl, and at least one substituent is fluorine, fluoroalkyl, fluoroalkoxy, fluoroaryl, or trifluoroaryl; Ar1 ​​is 0 to 2; and / or,

[0078] The metal is at least one of Ag, Al, Yb and Ce, and the metal oxide is at least one of IZO, ITO, ZnO, IGZO and ITZO.

[0079] In some embodiments, the material of the temporary shielding layer is selected from one or more of the following compounds:

[0080]

[0081]

[0082] In the above structural formula, B1, B2, B4, B5, B6, B7, B8, Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8, B'1, B'2, B'3, B'4, B'5, B'6 and B'8 are each independently selected from one or more of deuterium, fluorine, chlorine, C1-C6 alkyl, cycloalkyl, silyl, fluoroalkyl, arylalkyl, aryl, haloaryl, heteroaryl, alkoxy, haloalkoxy, fluoroalkoxy, fluoroaryl and trifluoroaryl.

[0083] In some embodiments, B1, B2, B4, B5, B6, B7, B8, Z1, Z2, Z3, Z4, Z5, Z6, Z7, Z8, B'1, B'2, B'3, B'4, B'5, B'6, and B'8 are each independently selected from: methyl, methoxy, ethyl, tert-butyl, fluoromethyl, difluoromethyl, trifluoromethyl, fluoroalkoxy, difluoromethoxy, trifluoromethoxy, fluoroethyl, polyfluoroethyl, 4-fluorophenyl, 3,4,5-trifluorophenyl, and 4-(trifluoromethoxy)phenyl.

[0084] In some embodiments, at least one of Z3 and Z7 is 3,4,5-trifluorophenyl.

[0085] In some embodiments, at least one of B1, B2, B4, B5, B6, B7, B8, B'1, B'2, B'3, B'4, B'5, B'6 and B'8 is trifluoromethyl.

[0086] In some embodiments, at least one of A1, A2, A3, A4, A5, A'1, A'2, A'4, A'5, and A'6 is fluorine.

[0087] In some embodiments, the fluorinated organic compound is selected from one or more of the following compounds:

[0088]

[0089]

[0090] In these embodiments, by selecting the above-mentioned compounds, on the one hand, these compounds do not adhere to the material of the intermediate connecting layer, and on the other hand, these compounds can be evaporated and removed at a certain temperature without damaging the intermediate connecting layer due to excessively high temperature during the evaporation process.

[0091] In some embodiments, the above-mentioned organic compounds can be prepared by suzuki coupling. Specifically, the above-mentioned compounds are generated by reacting anthracene bromide with trifluoromethyl and boric acid-substituted naphthalene and / or trifluorophenylboronic acid in the presence of Pd(PPh3)4 and potassium carbonate.

[0092] The trifluoromethyl-substituted naphthalenes mentioned above can be obtained commercially or prepared through a trifluoromethylation reaction.

[0093] In some embodiments, during the step of evaporating and removing the temporary shielding layer 100, the vacuum degree of evaporation is less than 10. -5 Torr, with a temperature of 100–250℃.

[0094] In these embodiments, the vacuum degree of evaporation is controlled to be less than 10. -5 Within the range of Torr and by controlling the evaporation temperature to be within the range of 100 to 250°C, damage to the intermediate connection layer, pixel openings, and even the temperature-sensitive first light-emitting unit below the intermediate connection layer due to excessive temperature can be avoided.

[0095] In some embodiments, such as Figure 1 As shown, the step of forming a temporary shielding layer 100 in the area not covered by the first light-emitting unit 30 includes:

[0096] A metal mask is used to shield the area where the first light-emitting unit 30 is located, and a temporary shielding layer 100 is formed in the area not covered by the first light-emitting unit 30 by vapor deposition.

[0097] In these embodiments, by using a metal mask to shield the area where the first light-emitting unit 30 is located, it can be ensured that the temporary shielding layer 100 is deposited in the area not covered by the first light-emitting unit 30. This reduces the amount of temporary shielding layer 100 deposited in the area where the first light-emitting unit 30 is located, and thus does not affect the formation of the intermediate connection layer 40 on the first light-emitting unit 30. This facilitates the subsequent connection between the first light-emitting unit 30 and the upper light-emitting unit through the intermediate connection layer 40.

[0098] In some embodiments, such as Figure 1 As shown, the preparation method further includes: S16, forming a second light-emitting unit 50 in at least one opening having an intermediate connecting layer 40 by printing; and forming an electrode in the region where the second light-emitting unit is located by vapor deposition.

[0099] In these embodiments, the hydrophobic properties of the pixel defining layer can be effectively utilized by printing the second light-emitting unit 50.

[0100] Embodiments of this application provide a light-emitting substrate, such as... Figure 2As shown, it includes: a substrate 10, a pixel defining layer 20 disposed on the substrate 10, the pixel defining layer 20 having a plurality of openings K; and a first light-emitting unit 30, an intermediate connecting layer 40 and a second light-emitting unit 50 disposed sequentially in the openings, the first light-emitting unit 30 being close to the substrate 10.

[0101] That is, in the light-emitting substrate provided in this application embodiment, the intermediate connection layer 40 is formed only in the opening K and only covers the area where the first light-emitting unit 30 is located, while the area where the first light-emitting unit 30 is not covered by the pixel defining layer 20 is not covered. In this way, the setting of the intermediate connection layer 40 does not affect the connection between the intermediate connection layer 40 and the light-emitting unit above the first light-emitting unit 30; on the other hand, the intermediate connection layer 40 does not cover the area where the first light-emitting unit 30 is not covered by the pixel defining layer 20, which can solve the problem of light emission crosstalk between adjacent light-emitting units caused by the full coverage of the intermediate connection layer 40 in the related art, as well as the problem that the full coverage of the intermediate connection layer 40 causes the original hydrophobic properties between pixel openings and the hydrophilic properties of the sidewalls of pixel openings to fail. Therefore, inkjet printing can be used to prepare light-emitting devices without seriously affecting the preparation of light-emitting devices by inkjet printing, making it possible to prepare stacked light-emitting devices by inkjet printing.

[0102] In some embodiments, such as Figure 1 and Figure 2 As shown, the intermediate connecting layer 40 can be prepared by the following method:

[0103] A first light-emitting unit 30 is formed in at least one opening K;

[0104] A temporary masking layer 100 is formed in the area not covered by the first light-emitting unit 30. The temporary masking layer 100 is used to mask the area of ​​the pixel boundary layer not covered by the first light-emitting unit.

[0105] An intermediate connecting layer 40 is formed in the region where the first light-emitting unit 30 is located;

[0106] Evaporation removes the temporary shielding layer 100.

[0107] In these embodiments, when the intermediate connecting layer 40 is prepared using the above method, a temporary shielding layer 100 can be used to temporarily shield and protect the area not covered by the first light-emitting unit 30. After the intermediate connecting layer 40 is formed, the temporary shielding layer 100 can be cleverly removed by using materials with different properties than those of the temporary shielding layer 100, while the intermediate connecting layer 40 located in the area where the first light-emitting unit 30 is located is retained, thereby solving the above-mentioned technical problem.

[0108] In some embodiments, the light-emitting substrate further includes an electrode disposed on the surface of at least one second light-emitting unit.

[0109] In some embodiments, the second light-emitting unit 50 is in direct contact with the sidewall of the opening K in which it is located.

[0110] In these embodiments, compared to the related art where the intermediate connecting layer 40 covers the entire surface and the second light-emitting unit 50 is formed in the opening K, making it impossible for the second light-emitting unit 50 to directly contact the sidewall of the opening, the portion of the second light-emitting unit 50 located in the corresponding opening K directly contacts the sidewall of the opening K. The hydrophobic properties between the openings and the hydrophilic properties on the sidewall of the opening can be utilized, thereby enabling the second light-emitting unit 50 to be fabricated by inkjet printing, making it possible to fabricate a multilayer light-emitting device by inkjet printing.

[0111] Some embodiments of this application provide a light-emitting device, including a light-emitting substrate as described above.

[0112] Examples of such light-emitting devices include televisions, computers, tablets, mobile phones, or ATMs.

[0113] In order to objectively evaluate the technical effects provided by this application, the following embodiments will be used to illustrate and describe this application in detail.

[0114] In the following embodiments, all raw materials are commercially available, and to maintain the reliability of the experiments, the raw materials used in the following embodiments have the same physical and chemical parameters or have undergone the same treatment.

[0115] Example 1

[0116] The method for preparing the light-emitting substrate provided in Example 1 is as follows:

[0117] Step 1) Form a pixel defining layer on an ITO substrate. The pixel defining layer has multiple openings, and a first light-emitting unit is formed in each opening. The first light-emitting unit includes, from bottom to top, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer. The hole injection layer, hole transport layer, light-emitting layer, electron transport layer, and electron injection layer can all be fabricated by printing. The material of the hole injection layer may include PEDOT:PSS; the material of the hole transport layer may include Poly-TPD; the material of the light-emitting layer may include RGB polymer light-emitting materials and RGB quantum dot light-emitting materials; the material of the electron transport layer may include TBPi; and the material of the electron injection layer may include LiF.

[0118] Step 2) Use a metal mask to block the area where the first light-emitting unit is located, and use vapor deposition to form a temporary shielding layer in the area not covered by the first light-emitting unit. The material of the temporary shielding layer is shown in the following formula (i).

[0119] Step 3) An intermediate connection layer is formed on the ITO substrate by vapor deposition. The material of the intermediate connection layer includes Ag. Since the adhesion coefficient between Ag and the temporary shielding layer is small, the intermediate connection layer is only formed in the region where the first light-emitting unit is located and is located on the electron injection layer of the first light-emitting unit.

[0120] Step 4) In a vacuum degree less than 10 -5 Torr, heated at 100°C, evaporates and removes the temporary shielding layer.

[0121] Step 5) A second light-emitting unit is formed on the intermediate connecting layer by printing. The second light-emitting unit includes, from bottom to top, a hole injection layer, a hole transport layer, a light-emitting layer, an electron transport layer, and an electron injection layer. During the printing process, due to the obstruction of the intermediate connecting layer, the organic solvent will not penetrate into the first light-emitting unit below, thus ensuring the stability of the first light-emitting unit.

[0122]

[0123] Example 2

[0124] The fabrication method of the light-emitting substrate in Example 2 is basically the same as that in Example 1. The difference is that the hole injection layer of the light-emitting substrate in Example 2 is made of HATCN, the hole transport layer is made of PVK, the electron transport layer is made of ZnO, and the electron injection layer is made of NaF. The material of the temporary shielding layer is shown in formula (ii), and the material of the intermediate connecting layer is Al. The heating temperature during the evaporation and removal of the temporary shielding layer is 150°C, and the vacuum degree is less than 10. -5 Torr.

[0125]

[0126] Example 3

[0127] The fabrication method of the light-emitting substrate in Example 3 is basically the same as that in Example 1. The difference is that the hole injection layer of the light-emitting substrate in Example 2 is made of MoO3, the hole transport layer is made of TFB, the electron transport layer is made of ZnO, and the electron injection layer is made of LiF. The material of the temporary shielding layer is shown in formula (iii), and the material of the intermediate connecting layer is IZO. The heating temperature is 250°C and the vacuum degree is less than 10 when the temporary shielding layer is evaporated and removed. -5 Torr.

[0128]

[0129] In summary, by using a fluorinated organic compound as a temporary shielding layer to cover the area not covered by the first light-emitting unit, the adhesion coefficient between the intermediate connecting layer material and the temporary shielding layer is very small. Therefore, the intermediate connecting layer can be formed only in the area where the first light-emitting unit is located and within the opening, without covering the pixel openings. This prevents crosstalk between adjacent light-emitting units caused by the entire surface of the intermediate connecting layer, and also preserves the original hydrophobic properties between the pixel openings and the original hydrophilic properties of the pixel opening sidewalls. This allows for the fabrication of the second light-emitting unit using inkjet printing, thus making it possible to fabricate stacked light-emitting devices using inkjet printing. Furthermore, experiments have shown that when using the aforementioned compound as a temporary shielding layer, the conductivity of the intermediate connecting layer itself can be maintained, without affecting the function of the intermediate connecting layer connecting the first and second light-emitting units in series.

[0130] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0131] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for preparing a light-emitting substrate, characterized in that, include: A pixel defining layer is formed on a substrate, the pixel defining layer having multiple openings; A first light-emitting unit is formed in at least one of the openings; A temporary shielding layer is formed in the area not covered by the first light-emitting unit, and the temporary shielding layer is used to shield the area of ​​the pixel boundary layer not covered by the first light-emitting unit; An intermediate connecting layer is formed in the region where the first light-emitting unit is located, and the adhesion coefficient between the material of the temporary shielding layer and the material of the intermediate connecting layer is less than 0.1; Evaporation is used to remove the temporary shielding layer, and the evaporation temperature is controlled to be 100°C to 250°C.

2. The method according to claim 1, characterized in that, The temporary shielding layer is made of organic materials; the intermediate connecting layer is made of inorganic materials.

3. The method according to claim 1 or 2, characterized in that, The temporary shielding layer is made of a fluorinated organic compound with a molecular weight of less than 1000.

4. The method according to claim 1 or 2, characterized in that, The intermediate connecting layer is made of metal or metal oxide.

5. The method according to claim 3, characterized in that, The material of the temporary shielding layer includes any one of the following compounds: （I） In compound (I), Ar1, Ar2, and Ar3 are independently selected from substituted or unsubstituted aryl groups having 6 to 50 carbon atoms and heteroaryl groups having 4 to 50 carbon atoms, respectively; the substituents in Ar1, Ar2, and Ar3 are independently selected from one or more of deuterium, fluorine, chlorine, C1 to C6 alkyl, cycloalkyl, silyl, fluoroalkyl, arylalkyl, aryl, haloaryl, heteroaryl, alkoxy, haloalkoxy, fluoroalkoxy, fluoroaryl, and trifluoroaryl, and at least one substituent is fluorine, fluoroalkyl, fluoroalkoxy, fluoroaryl, or trifluoroaryl; there are 0 to 2 substituents in Ar1.

6. The method according to claim 4, characterized in that, The metal is at least one of Ag, Al, Yb and Ce, and the metal oxide is at least one of IZO, ITO, ZnO, IGZO and ITZO.

7. The method according to claim 5, characterized in that, The fluorine-containing organic compound is selected from one or more of the following compounds: 、 、 。 8. The method according to claim 1, characterized in that, The evaporation in the step of removing the temporary shielding layer has a vacuum degree less than 10 -5 Torr, and a temperature of 100-250°C.

9. The method according to claim 1, characterized in that, The step of forming a temporary shielding layer in the area not covered by the first light-emitting unit includes: A metal mask is used to shield the area where the first light-emitting unit is located, and a temporary shielding layer is formed in the area not covered by the first light-emitting unit by vapor deposition.

10. The method according to claim 1, characterized in that, Also includes: A second light-emitting unit is formed in at least one opening in which the intermediate connecting layer is formed by printing; An electrode is formed in the region where the second light-emitting unit is located by vapor deposition.

11. The method according to claim 1, characterized in that, The intermediate connecting layer is formed in the region where the first light-emitting unit is located by vapor deposition or sputtering.

12. A light-emitting substrate, characterized in that, include: Substrate; A pixel defining layer is disposed on the substrate, the pixel defining layer having a plurality of openings; as well as A first light-emitting unit, an intermediate connecting layer, and a second light-emitting unit are sequentially stacked within the opening, with the first light-emitting unit close to the substrate. The intermediate connecting layer is prepared by the following method: A first light-emitting unit is formed in at least one opening; A temporary shielding layer is formed in the area not covered by the first light-emitting unit, and the temporary shielding layer is used to shield the area of ​​the pixel boundary layer not covered by the first light-emitting unit; An intermediate connecting layer is formed in the region where the first light-emitting unit is located, and the adhesion coefficient between the material of the temporary shielding layer and the material of the intermediate connecting layer is less than 0.1; Evaporation is used to remove the temporary shielding layer, and the evaporation temperature is controlled to be 100°C to 250°C.

13. The light-emitting substrate according to claim 12, characterized in that, Also includes: An electrode is disposed on the surface of at least one of the second light-emitting units.

14. The light-emitting substrate according to claim 12, characterized in that, The second light-emitting unit is in direct contact with the sidewall of the opening in which it is located.

15. A light-emitting device, characterized in that, include: The light-emitting substrate as described in any one of claims 12 to 14.

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