CN112331795A - Metal electrode layer, preparation method thereof and light-emitting device - Google Patents
Metal electrode layer, preparation method thereof and light-emitting device Download PDFInfo
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- 229910052751 metal Inorganic materials 0.000 title claims abstract description 174
- 239000002184 metal Substances 0.000 title claims abstract description 174
- 238000002360 preparation method Methods 0.000 title claims abstract description 26
- 239000002904 solvent Substances 0.000 claims abstract description 123
- 239000007772 electrode material Substances 0.000 claims abstract description 62
- 238000000034 method Methods 0.000 claims abstract description 36
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- 238000002834 transmittance Methods 0.000 claims description 16
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 12
- 238000009835 boiling Methods 0.000 claims description 12
- 238000004519 manufacturing process Methods 0.000 claims description 11
- 238000001291 vacuum drying Methods 0.000 claims description 11
- SMWDFEZZVXVKRB-UHFFFAOYSA-N Quinoline Chemical compound N1=CC=CC2=CC=CC=C21 SMWDFEZZVXVKRB-UHFFFAOYSA-N 0.000 claims description 10
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 8
- KWOLFJPFCHCOCG-UHFFFAOYSA-N Acetophenone Chemical compound CC(=O)C1=CC=CC=C1 KWOLFJPFCHCOCG-UHFFFAOYSA-N 0.000 claims description 8
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 8
- QPJVMBTYPHYUOC-UHFFFAOYSA-N methyl benzoate Chemical compound COC(=O)C1=CC=CC=C1 QPJVMBTYPHYUOC-UHFFFAOYSA-N 0.000 claims description 8
- 238000010438 heat treatment Methods 0.000 claims description 7
- 239000002245 particle Substances 0.000 claims description 7
- 239000002243 precursor Substances 0.000 claims description 6
- 229940095102 methyl benzoate Drugs 0.000 claims description 4
- 229910052709 silver Inorganic materials 0.000 claims description 4
- 239000004332 silver Substances 0.000 claims description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 4
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- YVTHLONGBIQYBO-UHFFFAOYSA-N zinc indium(3+) oxygen(2-) Chemical compound [O--].[Zn++].[In+3] YVTHLONGBIQYBO-UHFFFAOYSA-N 0.000 description 1
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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
- H10K50/80—Constructional details
- H10K50/805—Electrodes
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- 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
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- 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
- H10K71/60—Forming conductive regions or layers, e.g. electrodes
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Abstract
The invention relates to a metal electrode layer, a preparation method thereof and a light-emitting device. The preparation method comprises the following steps: forming a first solvent layer on a predetermined region of a substrate; forming a conductive ink layer on one side of the first solvent layer, which is far away from the substrate, wherein the conductive ink in the conductive ink layer comprises a second solvent and a metal electrode material; wherein a surface tension of the first solvent in the first solvent layer is greater than a surface tension of the second solvent. According to the preparation method, the coffee ring effect and the local excessive accumulation condition are avoided in the process of preparing the metal electrode in a printing mode, the prepared metal electrode is uniform in thickness, the light emitting efficiency of the light emitting device is effectively improved, and the requirement that the metal electrode is arranged on the light emitting side is met.
Description
Technical Field
The invention relates to the technical field of display, in particular to a metal electrode layer, a preparation method thereof and a light-emitting device.
Background
In recent years, Organic Light Emitting Diodes (OLEDs) have attracted attention because of their advantages such as wide color gamut, high contrast, rapid response, large viewing angle, and low power consumption, and are thus available as next-generation display technologies. In general, the structure of the organic light emitting diode includes: an anode, a hole injection layer, a hole transport layer, a light emitting layer, an electron transport layer, an electron injection layer, and a cathode. The anode and the cathode are usually formed by metal oxides with energy matching and better conductivity. Meanwhile, when the anode or the cathode is on the light-emitting side, there is a certain requirement on the transmittance of the anode or the cathode, such as: the top emission structure has certain requirements on the transmittance of the cathode and the transparent electrode above; similarly, in the bottom emission structure, the lower anode is also required to have better transmittance.
In the actual production process, the metal electrode is generally prepared by adopting an evaporation or sputtering method. Although evaporation and sputtering can form a thin film with uniform thickness, material waste is significant, and especially in the process of preparing an anode in a bottom emission structure, an extra etching process is required to remove redundant material to form a pixel-shaped electrode. Therefore, more and more people are beginning to try to prepare metal electrodes using inkjet printing, a method of additive manufacturing. The method widely used at present is to disperse metal nanoparticles or metal nanowires, etc. in a solvent to obtain a metal ink, and then perform inkjet printing on the metal ink to form a desired electrode pattern. After the electrode pattern is formed, the solvent in the metal ink is completely volatilized through drying treatment, only the metal nano particles or the metal nano wires which are originally dispersed in the ink are left, and then the metal nano particles or the metal nano wires are mutually fused through high-temperature sintering to form the metal electrode.
The metal electrode prepared by the traditional ink jet printing method has poor thickness uniformity and cannot meet the requirements of the metal electrode on the light emergent side. This is due on the one hand to the coffee ring effect during drying, which results in a large difference in thickness between the edge and the central area of the ink-jet printed metal electrode. On the other hand, because the stack formed by the metal nanoparticles or the metal nanowires after the drying treatment is relatively disordered, excessive accumulation is inevitably formed in a local part to ensure that the metal electrode completely covers the film forming surface, so that the local thickness is thicker. Considering that the thickness of the metal electrode has a significant influence on the transmittance, for example, when the thickness of the metal silver thin film is 5nm, the transmittance of visible light is about 85%, but when the thickness is increased to 10nm, the transmittance is only 50%, so that the metal electrode with uneven thickness can significantly reduce the light extraction efficiency of the device and reduce the brightness of the display panel.
Therefore, the metal electrode layer, the preparation method thereof and the light emitting device still need to be improved.
Disclosure of Invention
Based on this, there is a need for a method for preparing a metal electrode layer. According to the preparation method, in the process of preparing the metal electrode layer by adopting a printing mode, the coffee ring effect and the local excessive accumulation condition are avoided, the prepared metal electrode layer is uniform in thickness, the light emitting efficiency of the light emitting device is effectively improved, and the requirement that the metal electrode is arranged on the light emitting side is met.
A preparation method of a metal electrode layer comprises the following steps:
forming a first solvent layer on a predetermined region of a substrate;
forming a conductive ink layer on one side of the first solvent layer, which is far away from the substrate, wherein the conductive ink in the conductive ink layer comprises a second solvent and a metal electrode material;
wherein a surface tension of the first solvent in the first solvent layer is greater than a surface tension of the second solvent.
In one embodiment, the surface tension of the first solvent is greater than 40 dyn/cm; the surface tension of the second solvent is less than 25 dyn/cm.
In one embodiment, the boiling point of the first solvent is less than 250 ℃;
the second solvent has a boiling point of less than 100 ℃.
In one embodiment, the conductive ink layer is formed by ink jet printing based on the conductive ink, and the ink drop movement speed of the conductive ink is not more than 3 m/s.
In one embodiment, the first solvent is selected from at least one of water, quinoline, acetophenone, and methyl benzoate;
the second solvent is selected from at least one of methanol, ethanol and acetone.
In one embodiment, the mass fraction of the metal electrode material is 0.3-5% based on the total mass of the conductive ink;
the particle size of the metal electrode material is 2-20 nm;
the metal electrode material comprises silver or aluminum.
In one embodiment, the volume of the first solvent layer is 40-70 pL;
the volume of the conductive ink layer is 3-8 pL.
In one embodiment, the preparation method further comprises:
performing vacuum drying treatment on the first solvent layer and the conductive ink layer so as to form a metal electrode precursor layer;
heat-treating the metal electrode precursor layer to form the metal electrode layer;
wherein the pressure of the vacuum drying treatment is 10-4～10-5torr；
The temperature of the heat treatment is 120-200 ℃, and the time is 10-30 minutes.
The invention also provides a metal electrode layer, which is prepared by the preparation method. The metal electrode layer can thus have all the features and advantages of the previously described preparation method, which are not described in detail here.
The invention also provides a light-emitting device comprising the metal electrode layer; the thickness of the metal electrode layer is 3-10 nm, and the light transmittance is not lower than 80%. The metal electrode layer can have all the features and advantages of the metal electrode layer described above, and thus, the description thereof is omitted.
Compared with the prior art, the invention has the following beneficial effects:
according to the preparation method of the metal electrode layer, the conductive ink layer is formed by depositing the conductive ink on the surface of the first solvent, the surface tension of the first solvent is controlled to be larger than that of the second solvent in the conductive ink, and the boiling point of the first solvent is larger than that of the second solvent. Therefore, the metal electrode material can be pre-spread, the metal electrode material is transversely extruded by utilizing the surface area change in the evaporation process of the first solvent, the metal electrode material is tightly contacted with the first solvent, and a uniform and compact thin film is formed after the first solvent is completely volatilized. In the process, due to the extrusion effect in the evaporation process of the first solvent, the compact and pinhole-free surface of the final film can be ensured, excessive metal electrode materials do not need to be added into the conductive ink, and excessive accumulation is avoided being formed locally; and because the metal electrode material always stays on the surface of the first solvent and is not influenced by capillary flow in the first solvent, a coffee ring is not formed. Therefore, compared with the traditional ink jet printing method, the preparation method of the invention can form a metal electrode layer which is thinner, denser and more uniform in thickness. Meanwhile, the preparation method also has the following advantages:
(1) the metal electrode material is deposited in an additive manufacturing mode, so that no material is wasted, and no extra etching step is needed to remove redundant material;
(2) compared with the metal electrode layer prepared by the traditional ink-jet printing method, the metal electrode layer formed by the preparation method disclosed by the invention is thinner and more uniform in thickness, so that the metal electrode layer has higher transmittance and can be applied to the light emergent side of a display device;
(3) the metal electrode layer formed by the preparation method is more compact, so that the metal electrode layer has better conductivity, and can effectively protect the lower film layer from being damaged by sputtering when the transparent electrode (such as IZO) is sputtered;
(4) the undulated surface of the metal electrode layer formed by the preparation method can effectively perform partial scattering on the emitted light, so that the microcavity effect is weakened, and the visual angle of the top emission device is improved.
Drawings
Fig. 1 is a process flow diagram of a method for preparing a metal electrode layer according to an embodiment of the invention;
FIG. 2 is a schematic diagram of a metal electrode structure prepared by a conventional inkjet printing method;
FIG. 3 is a second schematic view of a metal electrode structure prepared by a conventional ink-jet printing method;
FIGS. 4 to 8 are schematic views illustrating a process of forming a metal electrode material film in a manufacturing method according to an embodiment of the invention;
FIGS. 9 to 10 are schematic diagrams illustrating a process of sintering a metal electrode material film layer to prepare a metal electrode layer according to an embodiment of the invention;
FIG. 11 is a schematic view illustrating a process of fabricating a transparent electrode on a surface of a metal electrode layer in a fabrication method according to an embodiment of the present invention;
FIG. 12 is a schematic view illustrating the light scattering effect of the metal electrode layer in the manufacturing method according to an embodiment of the invention;
wherein, 1: a base plate; 2: a thin film transistor layer; 3: a dam; 4: an anode; 5: a hole injection layer; 6: a hole transport layer; 7: a light emitting layer; 8: an electron transport layer; 9: an electron injection layer; 11: a transparent electrode; 12: a first solvent layer; 13: conductive ink; 131: a metal electrode material; 132: and a metal electrode layer.
Detailed Description
The quantum dot light emitting diode, the method for manufacturing the same, and the light emitting device of the present invention will be described in further detail with reference to specific embodiments.
Unless defined otherwise, 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 invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.
The embodiment of the invention provides a preparation method of a metal electrode layer, the process flow of which is shown in figure 1, and the preparation method comprises the following steps:
forming a first solvent layer on a predetermined region of a substrate;
forming a conductive ink layer on one side of the first solvent layer, which is far away from the substrate, wherein the conductive ink in the conductive ink layer comprises a second solvent and a metal electrode material;
wherein a surface tension of the first solvent in the first solvent layer is greater than a surface tension of the second solvent.
The substrate refers to a preform on which a metal electrode needs to be prepared, and the predetermined region is a pixel defining region (pixel pit) in a pixel unit. In the top emission light emitting device, the structure of the substrate includes at least an anode and a light emitting layer which are laminated, and may have the following structure: an anode/a hole injection layer/a hole transport layer/a light emitting layer/an electron transport layer/an electron injection layer, or an anode/a hole injection layer/a hole transport layer/a light emitting layer/an electron injection layer; in a bottom-emitting light emitting device, the substrate may then be a glass substrate.
The contact angle of the first solvent on the substrate surface is not strictly limited as long as the contact angle is not 0 degrees and the liquid does not completely wet the solid, that is, the material of the substrate is not particularly required. Generally, the electron injection layer has a higher surface energy, and the first solvent and the surface of the electron injection layer have better wetting effect, so that the three-phase contact line position is kept unchanged (namely the bottom area of the liquid drop is constant) during volatilization.
As shown in fig. 2 to 3, when the metal electrode is prepared by the conventional inkjet printing method: (1) the difference in thickness of the edge and central regions of the inkjet printed metal electrode is large due to the coffee ring effect during drying (fig. 2); (2) because the stack formed by the metal electrode material (such as metal nanoparticles or metal nanowires) after the drying process is relatively disordered, the thickness of the metal electrode layer is not uniform (fig. 3), and in order to avoid insufficient laying, even excessive metal electrode material is needed, so that the thickness of the formed metal electrode layer is thicker.
In this regard, the preparation method of the present invention advantageously avoids the above-mentioned problems by employing suitable said first and second solvents. The principle of the above-mentioned preparation method is illustrated in the following with reference to fig. 4 to 8, but not to limit the scope of the present invention. Specifically, taking a top-emission organic light emitting diode as an example, as shown in fig. 4, a substrate of the organic light emitting diode includes a bottom plate 1, a thin film transistor layer 2, and a bank 3 disposed on the thin film transistor layer 2, the bank 3 encloses a plurality of pixel units, and an anode 4, a hole injection layer 5, a hole transport layer 6, a light emitting layer 7, an electron transport layer 8, and an electron injection layer 9 are sequentially stacked in the pixel units. The preparation of the metal electrode is carried out on the basis of the electron injection layer 9, and the principle process is as follows:
as shown in fig. 4 and 5, in order to deposit the first solvent on the electron injection layer 9 to form the first solvent layer 12, and ensure that the conductive ink 13 can spread on the surface of the first solvent layer 12 to form the conductive ink layer without directly entering into the first solvent layer 12, the first solvent is required to have a higher surface tension than the second solvent in the conductive ink 13, and the surface tension of the first solvent is higher than that of the second solvent, which is beneficial for the metal electrode material 131 in the conductive ink 13 to be located on the surface of the first solvent layer 12 after the second solvent in the conductive ink is completely volatilized. In addition, since the deposited conductive ink 13 has a small volume and can be completely volatilized in a short time after being tiled, the metal electrode material 131 can be located on the surface of the first solvent layer 12 without requiring the second solvent in the conductive ink 13 to be immiscible with the first solvent.
As shown in fig. 6 to 8, the conductive ink 13 is deposited on the surface of the first solvent layer 12, the metal electrode material 131 therein is pre-spread, and the metal electrode material 131 is transversely extruded by using the surface area change during the evaporation process of the first solvent, so that the metal electrode material 131 is in close contact with the first solvent, and after the first solvent is completely volatilized, the metal electrode material 131 forms a conductive ink layer which is thinner and more compact than the conventional ink-jet printing method and has a more uniform thickness.
More specifically, as shown in fig. 9 to 10, after the drying, a sintering step is further included to finally form the metal electrode layer 132, and the steps include:
performing vacuum drying treatment on the first solvent layer and the conductive ink layer so as to form a metal electrode precursor layer;
heat-treating the metal electrode precursor layer to form the metal electrode layer;
wherein the pressure of the vacuum drying treatment is 10-4～10-5torr；
The temperature of the heat treatment is 120-200 ℃, and the time is 10-30 minutes.
In addition, in the top-emitting OLED display device, the metal electrode layer is used as a metal cathode, and in order to increase the transmittance of the metal cathode, the thickness of the metal electrode layer is generally relatively thin, so the conductivity is slightly poor, so a transparent electrode is usually deposited on the metal cathode to increase the conductivity of the whole cathode, and meanwhile, the transmittance of the transparent electrode is high, so that the light extraction of the OLED is not affected too much. In one specific embodiment, as shown in fig. 11, after the sintering, the transparent electrode 11 can be prepared on the metal electrode layer 132 to obtain a top-emitting OLED display device. In one specific embodiment, the transparent electrode 11 is formed by sputtering, and the material used is Indium Zinc Oxide (IZO). In this case, the dense metal electrode layer 132 can effectively protect the lower film layer from sputtering damage. Meanwhile, the metal electrode layer 132 formed by sintering the metal electrode material 131 still maintains the morphology of partial nanoparticles and has an undulating surface, so that light emitted by the OLED can be effectively and partially scattered, as shown in fig. 12, thereby reducing the microcavity effect and effectively improving the viewing angle of the top-emitting OLED.
Preferably, the surface tension of the first solvent is greater than 40 dyn/cm; and/or the surface tension of the second solvent is less than 25 dyn/cm. Thus, the metal electrode material in the conductive ink can spread more rapidly on the surface of the first solvent layer 12 and better maintain the surface of the first solvent layer 12.
More preferably, the surface tension of the first solvent is 40-73 dyn/cm; and/or the surface tension of the second solvent is 17-25 dyn/cm.
In some specific embodiments, the boiling point of the first solvent is greater than the boiling point of the second solvent. It will be appreciated that in other embodiments, even if the second solvent has a boiling point slightly greater than that of the first solvent, it will preferentially evaporate because the volume of the second solvent is generally smaller and the specific surface area increases upon spreading.
More specifically, the boiling point of the first solvent is less than 250 ℃; the second solvent has a boiling point of less than 100 ℃. Both of them can be volatilized rapidly in the vacuum drying stage, so that even if a part of the metal electrode material 131 enters below the liquid level of the first solvent layer 12, the diffusion speed is lower than the speed of the drop height descending movement when the first solvent is volatilized at a high speed, and therefore, the metal electrode material can still be captured (Surface Capture Effect) by the liquid level and cannot enter the first solvent layer 12.
Preferably, the boiling point of the first solvent is 80-250 ℃; and/or the boiling point of the second solvent is 50-100 ℃. Thereby, a proper volatilization rate can be obtained, so that the metal electrode material in the conductive ink can not enter the interior of the first solvent in the drying process.
Preferably, the conductive ink layer is formed by inkjet printing based on the conductive ink, and the ink droplet movement speed of the conductive ink is not more than 3 m/s. Therefore, the spreading of the metal electrode material on the surface of the first solvent is facilitated, and the direct entering of the ink drops of the conductive ink into the first solvent drops is avoided.
In some specific embodiments, the first solvent is selected from at least one of water, quinoline, acetophenone, and methyl benzoate. It will be appreciated that where the first solvent is water, it should be used in applications where it is not sensitive to moisture, such as in the fabrication of anodes for bottom-emitting devices.
In some specific embodiments, the second solvent is selected from at least one of methanol, ethanol, and acetone.
In some specific embodiments, the volume of the first solvent layer is 40-70 pL; the volume of the conductive ink layer is 3-8 pL. As described above, the predetermined region is a pixel defining region (pixel pit) in the pixel unit, and the volume of the first solvent layer and the volume of the conductive ink layer correspond to each pixel defining region (pixel pit).
In some specific embodiments, the metal electrode material may be nanoparticles of a metal such as silver, aluminum, or the like.
In some specific embodiments, the mass fraction of the metal electrode material is 0.3-5% based on the total mass of the conductive ink.
In some specific embodiments, the metal electrode material has a particle size of 2 to 20 nm.
In some specific embodiments, the method for preparing the metal electrode may include the following steps:
s1, depositing a first solvent on the position, where the metal electrode needs to be prepared, of the substrate through ink-jet printing;
for the pixel pit size of the existing inkjet printing OLED, the volume of the first solvent is about 40-70 pL, and the first solvent can be directly formed by one-time inkjet printing or formed by fusing a plurality of ink drops with smaller volumes in the pixel pits.
S2, depositing conductive ink on the surface of the first solvent through ink-jet printing, wherein the conductive ink is provided with a metal electrode material and is rapidly spread on the surface of the first solvent after the conductive ink contacts the surface of the first solvent to form a liquid film with the thickness of hundreds of nanometers and the metal electrode material;
the volume of the conductive ink is 3-8 pL, wherein the mass fraction of the metal electrode material is 0.3-5 wt.%, and the particle size of the metal electrode material is 2-20 nm.
S3, reducing the environmental pressure to 10-4～10～5Carrying out vacuum drying treatment on the first solvent and the conductive ink by a torr;
s4, after the first solvent is completely volatilized, the metal electrode material is uniformly and tightly deposited on the surface of the position on the substrate where the metal electrode needs to be prepared, and a thin layer of the metal electrode material is formed;
s5, heating the substrate to 120-200 ℃, and sintering the metal electrode materials for 10-30 min to fuse the metal electrode materials together to form a compact metal electrode film;
s6, if the thickness of the metal electrode film deposited at one time does not meet the requirement, repeating S1-S5 until the target thickness is reached. For a metal electrode (the thickness is usually 3-10 nm) on the light emergent side, the thickness requirement can be met by one-time deposition, and the light transmittance is not lower than 80%.
Embodiments of the present invention also provide a metal electrode layer, which is prepared by the preparation method described above. Thus, the metal electrode layer may have all the features and advantages of the method described above, and thus, the description thereof is omitted.
Embodiments of the present invention also provide a light emitting device including the metal electrode layer described above; the thickness of the metal electrode layer is 3-10 nm, and the light transmittance is not lower than 80%. Thus, the light emitting device can have all the features and advantages of the metal electrode layer described above, and thus, the description thereof is omitted.
The following are specific examples, and the starting materials used in the examples are all commercially available products unless otherwise specified.
Example 1
The embodiment is a method for preparing a metal electrode of a top-emitting OLED, which comprises the following steps:
s1, depositing a first solvent (quinoline) by ink-jet printing at the position where a metal electrode needs to be prepared on the substrate with the structure of anode/hole injection layer/hole transport layer/luminescent layer/electron transport layer/electron injection layer, wherein the volume of the first solvent (quinoline) is about 50 pL;
s2, depositing conductive ink (a methanol solution of silver nanoparticles, the mass fraction of the silver nanoparticles is 3%, and the particle size is 2-20 nm) on the surface of the first solvent through ink-jet printing, wherein the ink drop movement speed of the conductive ink is 3m/S, the volume of the conductive ink is 5pL, and the conductive ink is provided with a metal electrode material (silver nanoparticles) to form a layer of liquid film with the metal electrode material;
s3, reducing the environmental pressure to 10-4～10-5Carrying out vacuum drying treatment on the first solvent and the conductive ink by a torr;
s4, after the first solvent is completely volatilized, the metal electrode material is uniformly and tightly deposited on the surface of the position on the substrate where the metal electrode needs to be prepared, and a thin layer of the metal electrode material is formed;
and S5, heating the substrate to 180 ℃, and sintering the metal electrode materials for 20min to fuse the metal electrode materials together to form the metal electrode film. The thickness of the metal electrode layer is about 3-10 nm, the metal electrode layer is uniform and compact, coffee rings do not exist, and the light transmittance is larger than 80%.
Example 2
The embodiment is a method for preparing a metal electrode of a top-emitting OLED, which comprises the following steps:
s1, depositing a first solvent (acetophenone) by ink-jet printing at the position where a metal electrode needs to be prepared on the substrate with the structure of anode/hole injection layer/hole transport layer/luminescent layer/electron transport layer/electron injection layer, wherein the volume of the first solvent is about 50 pL;
s2, depositing conductive ink (an ethanol solution of silver nanoparticles, the mass fraction of the silver nanoparticles is 3%, and the particle size is 2-20 nm) on the surface of the first solvent through inkjet printing, wherein the ink drop movement speed of the conductive ink is 3m/S, the volume of the conductive ink is 5pL, and the conductive ink is provided with a metal electrode material (silver nanoparticles) to form a layer of liquid film with the metal electrode material;
s3, reducing the environmental pressure to 10-4～10-5Carrying out vacuum drying treatment on the first solvent and the conductive ink by a torr;
s4, after the first solvent is completely volatilized, the metal electrode material is uniformly and tightly deposited on the surface of the position on the substrate where the metal electrode needs to be prepared, and a thin layer of the metal electrode material is formed;
and S5, heating the substrate to 180 ℃, and sintering the metal electrode materials for 20min to fuse the metal electrode materials together to form the metal electrode film. The thickness of the metal electrode layer is about 3-10 nm, the metal electrode layer is uniform and compact, coffee rings do not exist, and the light transmittance is larger than 80%.
Example 3
The embodiment is a method for preparing a metal electrode of a top-emitting OLED, which comprises the following steps:
s1, depositing a first solvent (methyl benzoate) by ink-jet printing at the position where a metal electrode needs to be prepared on the substrate with the structure of anode/hole injection layer/hole transport layer/luminescent layer/electron transport layer/electron injection layer, wherein the volume is about 50 pL;
s2, depositing conductive ink (acetone solution of silver nanoparticles, the mass fraction of the silver nanoparticles is 3%, and the particle size is 2-20 nm) on the surface of the first solvent through ink-jet printing, wherein the ink drop movement speed of the conductive ink is 3m/S, the volume of the conductive ink is 5pL, and the conductive ink is provided with a metal electrode material (silver nanoparticles) to form a layer of liquid film with the metal electrode material;
s3, reducing the environmental pressure to 10-4～10-5Carrying out vacuum drying treatment on the first solvent and the conductive ink by a torr;
s4, after the first solvent is completely volatilized, the metal electrode material is uniformly and tightly deposited on the surface of the position on the substrate where the metal electrode needs to be prepared, and a thin layer of the metal electrode material is formed;
and S5, heating the substrate to 180 ℃, and sintering the metal electrode materials for 20min to fuse the metal electrode materials together to form the metal electrode film. The thickness of the metal electrode layer is about 3-10 nm, the metal electrode layer is uniform and compact, coffee rings do not exist, and the light transmittance is larger than 80%.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. The preparation method of the metal electrode layer is characterized by comprising the following steps:
forming a first solvent layer on a predetermined region of a substrate;
forming a conductive ink layer on one side of the first solvent layer, which is far away from the substrate, wherein the conductive ink in the conductive ink layer comprises a second solvent and a metal electrode material;
wherein a surface tension of the first solvent in the first solvent layer is greater than a surface tension of the second solvent.
2. The method of claim 1, wherein the first solvent has a surface tension of greater than 40 dyn/cm; the surface tension of the second solvent is less than 25 dyn/cm.
3. The method of claim 1, wherein the first solvent has a boiling point of less than 250 ℃;
the second solvent has a boiling point of less than 100 ℃.
4. The production method according to claim 1, wherein the conductive ink layer is formed by inkjet printing based on the conductive ink, and a droplet movement speed of the conductive ink is not more than 3 m/s.
5. The production method according to any one of claims 1 to 4, characterized in that the first solvent is at least one selected from the group consisting of water, quinoline, acetophenone and methyl benzoate;
the second solvent is selected from at least one of methanol, ethanol and acetone.
6. The production method according to any one of claims 1 to 4, characterized in that the mass fraction of the metal electrode material is 0.3 to 5% based on the total mass of the conductive ink;
the particle size of the metal electrode material is 2-20 nm;
the metal electrode material comprises silver or aluminum.
7. The method according to any one of claims 1 to 4, wherein the volume of the first solvent layer is 40 to 70 pL;
the volume of the conductive ink layer is 3-8 pL.
8. The method according to any one of claims 1 to 4, further comprising:
performing vacuum drying treatment on the first solvent layer and the conductive ink layer so as to form a metal electrode precursor layer;
heat-treating the metal electrode precursor layer to form the metal electrode layer;
wherein the pressure of the vacuum drying treatment is 10-4～10-5torr；
The temperature of the heat treatment is 120-200 ℃, and the time is 10-30 minutes.
9. A metal electrode layer, characterized in that the metal electrode layer is prepared by the preparation method of any one of claims 1 to 8.
10. A light-emitting device comprising the metal electrode layer according to claim 9;
the thickness of the metal electrode layer is 3-10 nm, and the light transmittance is not lower than 80%.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102682918A (en) * | 2011-03-17 | 2012-09-19 | 铼钻科技股份有限公司 | Method for manufacturing transparent electrode |
| US20140000942A1 (en) * | 2011-03-15 | 2014-01-02 | Lg Chem Ltd. | CONDUCTIVE INK COMPOSITION, PRINTING METHOD USING THE SAME AND CONDUCTIVE PATTERN MANUFACTURED BY THE SAME (As Amended) |
| WO2016047306A1 (en) * | 2014-09-26 | 2016-03-31 | 富士フイルム株式会社 | Process for producing film of metal oxide particles and process for producing metal film |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20140000942A1 (en) * | 2011-03-15 | 2014-01-02 | Lg Chem Ltd. | CONDUCTIVE INK COMPOSITION, PRINTING METHOD USING THE SAME AND CONDUCTIVE PATTERN MANUFACTURED BY THE SAME (As Amended) |
| CN102682918A (en) * | 2011-03-17 | 2012-09-19 | 铼钻科技股份有限公司 | Method for manufacturing transparent electrode |
| WO2016047306A1 (en) * | 2014-09-26 | 2016-03-31 | 富士フイルム株式会社 | Process for producing film of metal oxide particles and process for producing metal film |
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