CN109651882B - Hole injection layer ink for ink-jet printing and application thereof in organic light-emitting display - Google Patents

Hole injection layer ink for ink-jet printing and application thereof in organic light-emitting display Download PDF

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CN109651882B
CN109651882B CN201811580156.6A CN201811580156A CN109651882B CN 109651882 B CN109651882 B CN 109651882B CN 201811580156 A CN201811580156 A CN 201811580156A CN 109651882 B CN109651882 B CN 109651882B
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ink
pedot
jet printing
organic light
substrate
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CN109651882A (en
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郑国强
彭忠祥
史红辉
纪又新
刘春太
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Zhengzhou University
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Zhengzhou University
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    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
    • C09D11/00—Inks
    • C09D11/30—Inkjet printing inks
    • 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]
    • H10K50/17—Carrier injection layers
    • 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
    • H10K85/00—Organic materials used in the body or electrodes of devices covered by this subclass
    • H10K85/10—Organic polymers or oligomers
    • H10K85/111—Organic polymers or oligomers comprising aromatic, heteroaromatic, or aryl chains, e.g. polyaniline, polyphenylene or polyphenylene vinylene
    • H10K85/113—Heteroaromatic compounds comprising sulfur or selene, e.g. polythiophene
    • H10K85/1135—Polyethylene dioxythiophene [PEDOT]; Derivatives thereof

Abstract

The invention discloses a hole injection layer ink for ink-jet printing and application thereof in organic light-emitting display. The ink is prepared by mixing aqueous PEDOT solution and isopropanol. The ink is formed into a PEDOT film by performing ink-jet printing on the substrate subjected to oxygen plasma treatment and carbon tetrafluoride plasma treatment in the area of the organic light-emitting display pixels by an ink-jet printer. The PEDOT ink disclosed by the invention is simple in composition and preparation method, stable in auxiliary solvent performance, low in content and strong in volatility, is easy to dry and remove after being printed and formed into a film, and cannot cause surface roughness, electrical property change and the like of a PEDOT film due to too long drying time. The PEDOT film has high uniformity, no obvious phenomena of thin middle and thick edge, and avoids the generation of coffee ring effect. And the matching between the height of the etched isolation column and a plurality of functional layers is improved. Has good application prospect.

Description

Hole injection layer ink for ink-jet printing and application thereof in organic light-emitting display
Technical Field
The invention belongs to the technical field of ink-jet printing organic light-emitting display. Relates to a hole injection layer ink for ink-jet printing and application thereof in organic light-emitting display.
Background
Organic light emitting diode displays (OLEDs) have the characteristics of being ultra-thin and flexible, having a wide viewing angle, having a high contrast ratio, having low power consumption, and the like, and are considered as a next-generation flat panel display technology that replaces liquid crystals. The inkjet printing organic light emitting display has low processing cost and high production efficiency, and is the high-generation organic light emitting display panel mass production processing technology with the most potential acknowledged by the industry.
OLEDs typically comprise: the organic electroluminescent device comprises a substrate, an anode arranged on the substrate, a hole injection layer arranged on the anode, a hole transport layer arranged on the hole injection layer, a luminescent layer arranged on the hole transport layer, an electron transport layer arranged on the luminescent layer, and a cathode (shown in figure 1) arranged on the electron transport layer, and comprises a plurality of functional layers. The light emitting principle of the OLED display 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. An OLED display device generally uses an ITO pixel electrode and a metal electrode as an anode and a cathode of the device, respectively, and under a certain voltage driving, electrons and holes are injected from the cathode and the anode to an electron transport layer and a hole transport layer, respectively, and the electrons and the holes migrate to a light emitting layer through the electron transport layer and the hole transport layer, respectively, and meet in the light emitting layer to form excitons and excite light emitting molecules, which emit visible light through radiation relaxation.
The most common fabrication methods for OLED devices are: the hole injection layer, the hole transport layer and the luminescent layer are prepared by adopting an ink-jet printing method. The inkjet printing method is to drop functional material ink into a predetermined pixel region using a single or multiple heads and then obtain a desired thin film by drying, and has advantages of high material utilization rate, low cost, and the like.
Namely, the ink-jet printing organic light-emitting display is to process light-emitting pixel units on an organic light-emitting display panel by adopting an ink-jet printing technology. The key of the high-performance organic light-emitting display panel for ink-jet printing is to ensure the thickness uniformity of functional films in a printing pixel unit, such as a hole injection layer, a three-primary-color organic light-emitting layer, an electron injection layer and the like. The thin film with uniform thickness is the key to improve the effective light-emitting area of the pixels of the display panel, the uniformity of the brightness of the panel and the service life.
In actual operation, the film printed by the ink jet printing usually has coffee ring effect, and uneven phenomenon that the center of the film is thin and the edge of the film is thick is formed. In the inkjet printing organic light emitting display, the isolation pillars are usually adopted to limit the free spreading of ink, so that the size of a printing pixel structure is reduced, and the resolution of a display panel is improved. The meniscus effect of the injected ink under the restriction of the pillars also causes non-uniformity in the film thickness. And the height of the isolation column cannot simultaneously meet the requirement of simultaneous matching of a plurality of functional layers for printing ink.
In order to improve the uniformity of the film in the pixel unit of inkjet printing under the limit of the isolation column, U.S. patent No. US7102280 reports that a horizontal meniscus is formed when gelation occurs during the drying process of the printing ink by a method of matching the height of the isolation column with the amount of ink of the printing polymer material, thereby obtaining a film with uniform thickness after the ink is dried. Although the technology solves the problem of non-uniformity of the film to a certain extent, the heights of the isolation columns cannot simultaneously meet the requirement of simultaneous matching of a plurality of functional layers for printing ink. When the height of the isolation column is matched with the printing condition of the ink for printing the hole injection layer, in order to ensure that the uniform organic light-emitting film is obtained by continuously printing on the hole injection layer, the composition and the printing condition of the organic light-emitting material ink must be adjusted necessarily so as to increase the matching between the height of the isolation column and the composition and the printing condition of the organic light-emitting material ink. This results in difficult application of the technology, high process complexity and low process latitude available for production.
Disclosure of Invention
The invention aims at the technical problems that: in the prior art, the thickness of a film of a hole injection layer obtained by ink for the hole injection layer used by an ink-jet printing method is uneven, so that the uniformity and the service life of the effective light-emitting area and the brightness of a panel are influenced, and the thickness of the film is further uneven due to the meniscus effect of the injected ink under the limitation of an isolation column. And the height of the isolation column cannot meet the requirement of matching of a plurality of functional layers when printing ink, and the film uniformity of other functional layers can be influenced. Therefore, in the ink-jet printing process, the film thickness of the hole injection layer prepared by the ink-jet printing ink is not uniform, and meanwhile, the film thickness of other functional layers is not uniform due to the fact that the heights of the isolation columns cannot meet the requirements of a plurality of functional layers at the same time, so that the influences on the effective light-emitting area of pixels of the display panel and the brightness of the panel are further increased.
In view of the above problems, the present invention provides a hole injection layer ink for inkjet printing, which has a wide pillar height adaptability, i.e., a thin film with small thickness fluctuation can be obtained by printing in a wider range of the ratio of the pillar height to the average thickness of the printed ink layer. The coffee ring effect can be avoided, the uniformity of the film is ensured, and the height of the isolation column can be matched with a plurality of functional layers.
The invention also provides application of the ink of the hole injection layer for ink-jet printing in organic light-emitting display (namely application of the ink in film forming of the hole injection layer for ink-jet printing), and the film obtained by printing with the ink has good uniformity, so that the matching degree of the height of the isolation column and a plurality of functional layers is high, the effective light-emitting area of pixels of a display panel can be obviously improved, the uniformity of the brightness of the panel is improved, and the service life of the panel is prolonged.
The invention is realized by the following technical scheme
The ink for the ink-jet printing hole injection layer is mainly prepared from the following raw materials in percentage by volume: 90-97.5% of PEDOT aqueous solution and 2.5-10% of auxiliary solvent.
The ink for the ink-jet printing hole injection layer is characterized in that the auxiliary solvent is isopropanol;
preferably, the volume percentage of the isopropanol in the ink is 2.5-5%.
The ink for the hole injection layer in the ink-jet printing process has the surface tension of 40-51 mN/m;
preferably, the surface tension of the ink is 45-51 mN/m.
The PEDOT film is formed by ink-jet printing the ink-jet printing hole injection layer by ink.
The PEDOT film for the ink-jet printing hole injection layer comprises the following steps:
(1) preparing raw materials of isopropanol and a PEDOT aqueous solution according to a required proportion, and uniformly mixing the isopropanol and the PEDOT aqueous solution to form PEDOT ink;
(2) processing an isolation column pattern on a substrate;
(3) firstly, carrying out oxygen plasma treatment on the substrate with the pattern of the isolation columns, and then carrying out carbon tetrafluoride plasma treatment on the substrate to obtain a substrate with hydrophobic isolation column surfaces and hydrophilic organic light-emitting display pixel regions (namely regions among the isolation columns and anode regions);
(4) and (2) filtering the PEDOT ink obtained in the step (1), filling the PEDOT ink into an ink-jet printing system, printing the PEDOT ink on the hydrophilic organic light-emitting display pixel area on the substrate, and evaporating and drying the PEDOT ink to obtain a PEDOT film with uniform thickness so as to finish the ink-jet printing of the ink.
The PEDOT film for the hole injection layer of the ink-jet printing is characterized in that the specific process of processing the isolation column pattern on the substrate in the step (2) is as follows: spin-coating photoresist on an ITO glass substrate by using a spin coater, carrying out ultraviolet exposure treatment by using a photoetching machine, then carrying out development, flushing by using deionized water, and drying by using nitrogen to obtain an isolation column pattern;
the method specifically comprises the following steps: spin-coating photoresist on an ITO glass substrate by using a spin coater, heating on a hot table at 165 ℃ for 4min, cooling at room temperature, and performing ultraviolet exposure treatment by using a photoetching machine for 65 s; heating on a heating table at 110 ℃ for 4min, cooling at room temperature, developing for 30-40 s, washing with deionized water, and drying with nitrogen to obtain an isolation column pattern;
preferably, the rotating speed in the spin coating process is 1500-2500 rpm, and the rotating speed is changed at different room temperatures.
According to the PEDOT film for the hole injection layer through ink-jet printing, the width of the obtained isolation columns is 50 micrometers, the width of grooves among the isolation columns is 200 micrometers, and the height of the isolation columns is 2.0-2.5 micrometers.
The PEDOT film of the hole injection layer is printed by ink-jet printing, and the oxygen flow rate during the oxygen plasma treatment in the step (3) is 28sccm/s, the power is 100w, and the time is 150-210 s; the flow rate of carbon tetrafluoride during the carbon tetrafluoride plasma treatment is 98sccm/s, the power is 150w, and the time is 60s-90 s;
after plasma treatment, the height of the obtained isolation column is 1.5-2.0 μm;
after the isolated column is subjected to pattern processing in the step (3), the water contact angle of the surface of the isolated column is larger than 90 degrees; a water contact angle of a region of the organic light emitting display pixels on the substrate is less than 25 ° (i.e., a water contact angle of a region between the pillars);
preferably, the water contact angle of the surface of the separation column after treatment is more than 110 degrees.
The PEDOT film with the hole injection layer is printed by ink-jet printing, and a 0.2-micrometer nylon microporous filter membrane is adopted for filtering when the PEDOT ink in the step (4) is filtered; when the PEDOT ink in the step (4) is printed in the area of the hydrophilic organic light-emitting display pixels on the substrate, the ratio of the thickness of the ink layer printed in the area to the height of the isolation column after plasma treatment is (3-7): 1;
the drying in the step (4) is heating for 4min on a hot bench at 200 ℃.
The ink for the ink-jet printing hole injection layer and the PEDOT film for the ink-jet printing hole injection layer are applied to organic light-emitting display.
The PEDOT ink is printed on a substrate in an organic light-emitting display pixel area between an isolation column and the isolation column by an ink-jet printing method, and is dried to form a film (the obtained film has good uniformity, and the generation of a coffee ring effect with a thin middle part and a thick edge is avoided), so that a hole injection layer is obtained, namely the hole injection layer is made of Poly (3,4-ethylenedioxythiophene) -Polystyrene sulfonic acid (English name: Poly (3,4-ethylenedioxythiophene) Polystyrene sulfonate, which is called PEDOT for short).
Compared with the prior art, the invention has the following positive beneficial effects
The PEDOT ink can obtain a PEDOT film with smaller thickness fluctuation in a larger proportion range of the height of the isolation column and the average thickness of the ink layer, the obtained film has higher uniformity, the phenomena of thin middle and thick edge are avoided, and the coffee ring effect is avoided.
And the thickness range of the obtained uniform PEDOT film is larger at the fixed height of the isolation column. Or the height of the optional isolation column is wider under the condition of the same thickness of the PEDOT film. Therefore, when the height of the isolation column needs to be designed to be matched with the quantity of ink for printing the organic light-emitting layer so as to realize the printing of the organic light-emitting layer with uniform thickness, the PEDOT ink disclosed by the invention can be used for relaxing the limit on the optional range of the height of the isolation column, increasing the matching property of the height of the isolation column and the ink of the organic light-emitting material, improving the tolerance of the whole printing process design and effectively solving the problem that the height of the isolation column cannot be matched with a plurality of functional layers;
meanwhile, the composition and the preparation method of the PEDOT ink are simple, the auxiliary solvent is stable in performance, low in content and high in volatility, the PEDOT ink is easy to dry and remove after being printed and formed into a film, and the problems of surface roughness, electrical property change and the like of the PEDOT film caused by too long drying time are solved.
Drawings
FIG. 1 is a diagram of a conventional OLED structure;
FIG. 2 is a molecular structural diagram of PEDOT;
FIG. 3 is a schematic diagram of a film forming process of ink-jet printing PEDOT ink when the height of the spacer is equal to the height required for matching the PEDOT ink; wherein (a) is a schematic diagram of the process of aligning printing liquid drops to be deposited on the surface of the pixel electrode between the isolation columns, and (b) is a schematic diagram of the PEDOT film formed by drying the ink.
The meaning of the symbols in the figures is: 1 is a substrate, 2 is an isolation column, 3 is a meniscus of printed PEDOT ink, 4 is the height of the PEDOT ink when gelation occurs, and 5 is the height of a dry PEDOT film; h represents the height of the isolation column;
fig. 4 is a schematic diagram of the ink film forming process when the height of the isolation pillars is greater than the matching height of PEDOT ink, wherein (a) is commercial PEDOT ink using pure water as a solvent, and (b) is PEDOT ink according to the present invention. Compared with commercial ink, the ink has small meniscus curvature, and can obtain a PEDOT film with smaller thickness fluctuation on a larger area ratio;
fig. 5 is a schematic diagram of the ink film forming process when the height of the spacer is less than the matching height of the PEDOT ink, wherein (a) is commercial PEDOT ink using pure water as a solvent, and (b) is the PEDOT ink of the present invention. Compared with commercial ink, the ink has small curvature of the meniscus, and can obtain a PEDOT film with smaller thickness fluctuation on a larger area ratio;
FIG. 6 is a schematic illustration of a data acquisition method for printed PEDOT film thickness relief measurement;
fig. 7 is thickness test data of PEDOT thin films printed according to examples and comparative examples of the present invention.
Detailed Description
The present invention is described in more detail below with reference to specific examples, but the present invention is not limited to the following examples.
The printing system used in the following examples is an AD-P-8000 professional printing system of Microdrop Technologies, Germany. The photoresist is made by Futurrex company in the United statesThe negative photoresist is NR71-1500 PY. The PEDOT aqueous solution is purchased from Heraeus, Germany and has the model of CleviosTMP VP AI 4083(PEDOT content in water solution is 1.3-1.7 wt%), and the PEDOT material has a molecular structure shown in figure 1.
The process of ink-jet printing PEDOT ink to form PEDOT films is shown in figure 2: the PEDOT ink is formed into micron-sized droplets by an inkjet printing system and is aligned to be deposited on the substrate 1 on the surface of the area of the organic light emitting display pixel between the spacers 2 (i.e. the anode surface), and then is limited by the spacers 2 to spread only on the anode surface, forming an ink meniscus 3 with a certain curvature. When the amount of the printed PEDOT ink matches the height of the spacer, the gel height 4 is as high as the spacer 2 as the printed ink evaporates and gels, and under these conditions it dries (heated on a 200 ℃ hot plate for 4min) to form a smooth PEDOT film 5.
Figures 3 and 4 are the case when the spacer height is greater and less than the height that the printed PEDOT ink needs to match, respectively. The PEDOT ink provided by the invention has lower surface tension, so that the meniscus curvature is smaller compared with commercial PEDOT water, a PEDOT film with smaller thickness fluctuation can be obtained on a larger area ratio, and the uniformity of the printed PEDOT film is improved.
Figure 5 shows the data acquisition method for uniformity characterization of printed PEDOT films:
where w1 is the width of the printed PEDOT film.
The point A is the central point of the PEDOT film, and the distance w2 between the point A and the edge of the PEDOT film is equal to 0.5w 1.
The distances from point B1 and point B2 to point a are both w3, which is numerically equal to 0.4w 1.
In the present invention, the thickness of the PEDOT film is the value of the film thickness at the a point, and the height of the film is the difference between the value of the a point thickness and the average value of the thickness of the PEDOT film at the B1 and B2 points. The uniformity of the film thickness is characterized by the magnitude of the film height fluctuation.
The invention provides ink for an ink-jet printing hole injection layer, which is mainly prepared from the following raw materials in percentage by volume: 90-97.5% of PEDOT aqueous solution and 2.5-10% of auxiliary solvent; the auxiliary solvent is isopropanol.
Preferably, the volume percentage of the isopropanol in the ink is 2.5-5%.
The surface tension of the obtained ink for ink-jet printing is 40-51 mN/m;
preferably, the surface tension of the ink for ink jet printing is 45 to 51 mN/m.
The invention also provides a PEDOT film for ink-jet printing of the hole injection layer, wherein the PEDOT film is formed by ink-jet printing of the ink-jet printing hole injection layer.
The invention also provides a method for performing ink-jet printing on the PEDOT film of the ink-jet printing hole injection layer by adopting the ink-jet printing ink, which comprises the following steps:
(1) preparing raw materials of isopropanol and a PEDOT aqueous solution according to a required proportion, and uniformly mixing the isopropanol and the PEDOT aqueous solution to form PEDOT ink;
(2) processing an isolation column pattern on a substrate;
the method specifically comprises the following steps: spin-coating photoresist on an ITO glass substrate by using a spin coater, heating on a hot table at 165 ℃ for 4min, cooling at room temperature, and performing ultraviolet exposure treatment by using a photoetching machine for 65 s; heating on a heating table at 110 ℃ for 4min, cooling at room temperature, developing for 30-40 s, washing with deionized water, and drying with nitrogen to obtain an isolation column pattern;
preferably, the rotating speed in the spin coating process is 1500-2500 rpm; since the photoresist viscosity is temperature dependent, the rotation speed varies at different room temperatures.
More preferably, the rotation speed during the spin coating process is 2100 rpm.
The width of the obtained isolation columns is 50 micrometers, the width of grooves among the isolation columns is 200 micrometers, and the height of the isolation columns is 2.0-2.5 micrometers;
preferably, the height of the resulting separation column is 2.3. mu.m.
(3) Firstly, carrying out oxygen plasma treatment on the substrate with the pattern of the isolation columns, and then carrying out carbon tetrafluoride plasma treatment on the substrate to obtain a substrate with hydrophobic isolation column surfaces and hydrophilic organic light-emitting display pixel regions (namely regions among the isolation columns and anode regions);
the oxygen flow during the oxygen plasma treatment is 28sccm/s, the power is 100w, and the time is 150-210 s; the flow rate of carbon tetrafluoride during the carbon tetrafluoride plasma treatment is 98sccm/s, the power is 150w, and the time is 60s-90 s;
after plasma treatment, the height of the obtained isolation column is 1.5-2.0 μm;
preferably, the height of the resulting separation column after the plasma treatment is 1.8. mu.m.
After the isolated column is subjected to pattern processing, the water contact angle of the surface of the isolated column is larger than 90 degrees; a water contact angle of a region of the organic light emitting display pixels on the substrate is less than 25 ° (i.e., a water contact angle of a region between the pillars);
preferably, the water contact angle of the surface of the separation column after treatment is more than 110 degrees.
(4) And (2) filtering the PEDOT ink obtained in the step (1), filling the PEDOT ink into an ink-jet printing system, printing the PEDOT ink on the hydrophilic organic light-emitting display pixel area on the substrate, and evaporating and drying the PEDOT ink to obtain a PEDOT film with uniform thickness so as to finish the ink-jet printing of the ink.
The PEDOT ink is filtered by a 0.2 mu m nylon microporous filter membrane; when the PEDOT ink is printed on a hydrophilic organic light-emitting display pixel area on a substrate, the ratio of the thickness of the ink layer printed in the area to the height of the isolation column obtained after plasma treatment is (3-7): 1;
the drying is carried out by heating on a hot bench at 200 ℃ for 4 min.
The ink for the ink-jet printing hole injection layer and the PEDOT film for the ink-jet printing hole injection layer are applied to organic light-emitting display.
The specific embodiment is as follows:
example 1
An ink for an ink-jet printing hole injection layer is prepared from 97.5% by volume of PEDOT aqueous solution and 2.5% by volume of isopropanol;
the surface tension of the resulting ink was 51 mN/m.
The ink is prepared by uniformly mixing and stirring PEDOT aqueous solution and isopropanol.
Example 2
An ink for an ink-jet printing hole injection layer is prepared from 95 volume percent of PEDOT aqueous solution and 5 volume percent of isopropanol;
the surface tension of the resulting ink was 45 mN/m.
The ink is prepared by uniformly mixing and stirring PEDOT aqueous solution and isopropanol.
Example 3
An ink for an ink-jet printing hole injection layer, which is prepared from 92.5% by volume of PEDOT aqueous solution and 7.5% by volume of isopropanol;
the surface tension of the resulting ink was 42 mN/m.
The ink is prepared by uniformly mixing and stirring PEDOT aqueous solution and isopropanol.
Example 4
An ink for an ink-jet printing hole injection layer is prepared from 90% by volume of PEDOT aqueous solution and 10% by volume of isopropanol;
the surface tension of the resulting ink was 40 mN/m.
The ink is prepared by uniformly mixing and stirring PEDOT aqueous solution and isopropanol.
The invention also provides a PEDOT film (namely a hole injection layer) formed by ink-jet printing of the PEDOT ink in the embodiment 1-4.
Example 5
One of the ink-jet printing methods for forming a PEDOT film by ink-jet printing using the PEDOT ink described in example 1, the method comprising the steps of:
(1) measuring 0.25 ml of isopropanol, adding the isopropanol into 9.75 ml of PEDOT aqueous solution, and uniformly stirring and mixing to form printable PEDOT ink;
(2) processing an isolation column pattern on a substrate of a printing system: spin-coating photoresist on an ITO glass substrate by using a spin coater (the rotating speed in the spin coating process is 2100rpm), heating on a hot table at 165 ℃ for 4min, cooling at room temperature, and then carrying out ultraviolet exposure treatment by using a photoetching machine for 65 s; heating on a heating table at 110 ℃ for 4min, cooling at room temperature, developing for 30-40 s, washing with deionized water, and drying with nitrogen to obtain an isolation column pattern;
the width of the obtained isolation columns is 50 μm, the width of the groove between the isolation columns is 200 μm (the height is 2.3 μm before plasma etching and 1.8 μm after plasma etching);
(3) performing oxygen plasma treatment on the substrate with the isolating column pattern, and then performing carbon tetrafluoride plasma treatment, wherein the oxygen plasma treatment conditions are as follows: the oxygen flow is 28sccm/s, the power is 100w, the time is 180s, and the carbon tetrafluoride plasma treatment conditions are as follows: the flow rate of carbon tetrafluoride is 98sccm/s, the power is 150w, and the time is 60 s;
after the treatment is finished, obtaining a substrate with the surface water contact angle of 100 degrees and the water contact angle of an ITO area (anode area) of an organic light-emitting display pixel of 20 degrees;
(4) filtering the PEDOT ink prepared in the step (1) by adopting a 0.2-micrometer nylon microporous filter membrane, filling the filtered PEDOT ink into an ink-jet printing system, then printing the PEDOT ink on a hydrophilic organic light-emitting display pixel area on a substrate in an aligning way, and controlling the ratio of the thickness of a printed ink layer to the height of an isolation column to be (3-7): 1; evaporating the printing ink to generate gel, drying (heating for 4min at 200 ℃) to obtain a PEDOT film;
the films obtained in this example were tested according to the data acquisition method described in fig. 5: the thickness fluctuation of the PEDOT film is within 9nm, as shown by curve 1 in figure 6 (the ratio of the thickness of the printed ink layer to the height of the isolation column is controlled to be (3-7): 1).
Example 6
A third method of ink jet printing using PEDOT ink as described in example 2 to form a PEDOT film by ink jet printing, the method comprising the steps of:
(1) measuring 0.50 ml of isopropanol, adding the isopropanol into 9.50 ml of PEDOT aqueous solution, and uniformly stirring and mixing to form printable PEDOT ink;
(2) processing an isolation column pattern on a substrate of a printing system: spin-coating photoresist on an ITO glass substrate by using a spin coater (the rotating speed in the spin coating process is 2100rpm), heating on a hot table at 165 ℃ for 4min, cooling at room temperature, and then carrying out ultraviolet exposure treatment by using a photoetching machine for 65 s; heating on a heating table at 110 ℃ for 4min, cooling at room temperature, developing for 30-40 s, washing with deionized water, and drying with nitrogen to obtain an isolation column pattern;
the width of the obtained isolation columns is 50 μm, the width of the groove between the isolation columns is 200 μm (the height is 2.3 μm before plasma etching and 1.8 μm after plasma etching);
(3) performing oxygen plasma treatment on the substrate with the isolating column pattern, and then performing carbon tetrafluoride plasma treatment, wherein the oxygen plasma treatment conditions are as follows: oxygen flow rate is 28sccm/s, power is 100w, time is 150s, and carbon tetrafluoride plasma processing conditions are as follows: the flow rate of carbon tetrafluoride is 98sccm/s, the power is 150w, and the time is 90 s;
after the treatment is finished, obtaining a substrate with the surface water contact angle of 110 degrees and the water contact angle of 25 degrees in an ITO area (anode area) of the organic light-emitting display pixel;
(4) filtering the PEDOT ink prepared in the step (1) by adopting a 0.2-micrometer nylon microporous filter membrane, filling the filtered PEDOT ink into an ink-jet printing system, then printing the PEDOT ink on a hydrophilic organic light-emitting display pixel area on a substrate in an aligning way, and controlling the ratio of the thickness of a printed ink layer to the height of an isolation column to be (3-7): 1; evaporating the printing ink to generate gel, drying (heating for 4min at 200 ℃) to obtain a PEDOT film;
the films obtained in this example were tested according to the data acquisition method described in fig. 5: the thickness fluctuation of the PEDOT film is within 10nm, as shown by curve 2 in figure 6 (the ratio of the thickness of the printed ink layer to the height of the isolation column is controlled to be (3-7): 1).
Example 7
A third method of ink jet printing using PEDOT ink as described in example 3 to form a PEDOT film by ink jet printing, the method comprising the steps of:
(1) measuring 0.75 ml of isopropanol, adding the isopropanol into 9.25 ml of PEDOT aqueous solution, and uniformly stirring and mixing to form printable PEDOT ink;
(2) processing an isolation column pattern on a substrate of a printing system: spin-coating photoresist on an ITO glass substrate by using a spin coater (the rotating speed in the spin coating process is 2100rpm), heating on a hot table at 165 ℃ for 4min, cooling at room temperature, and then carrying out ultraviolet exposure treatment by using a photoetching machine for 65 s; heating on a heating table at 110 ℃ for 4min, cooling at room temperature, developing for 30-40 s, washing with deionized water, and drying with nitrogen to obtain an isolation column pattern;
the width of the obtained isolation columns is 50 μm, the width of the groove between the isolation columns is 200 μm (the height is 2.3 μm before plasma etching and 1.8 μm after plasma etching);
(3) performing oxygen plasma treatment on the substrate with the isolating column pattern, and then performing carbon tetrafluoride plasma treatment, wherein the oxygen plasma treatment conditions are as follows: oxygen flow rate is 28sccm/s, power is 100w, time is 150s, and carbon tetrafluoride plasma processing conditions are as follows: the flow rate of carbon tetrafluoride is 98sccm/s, the power is 150w, and the time is 90 s;
after the treatment is finished, obtaining a substrate with the surface water contact angle of 110 degrees and the water contact angle of 25 degrees in an ITO area (anode area) of the organic light-emitting display pixel;
(4) filtering the PEDOT ink prepared in the step (1) by adopting a 0.2-micrometer nylon microporous filter membrane, filling the filtered PEDOT ink into an ink-jet printing system, then printing the PEDOT ink on a hydrophilic organic light-emitting display pixel area on a substrate in an aligning way, and controlling the ratio of the thickness of a printed ink layer to the height of an isolation column to be (3-7): 1; evaporating the printing ink to generate gel, drying (heating for 4min at 200 ℃) to obtain a PEDOT film;
the films obtained in this example were tested according to the data acquisition method described in fig. 5: the thickness fluctuation of the PEDOT film is within 8nm, as shown by curve 3 in figure 6 (the ratio of the thickness of the printed ink layer to the height of the isolation column is controlled to be (3-7): 1).
Example 8
One of the ink-jet printing methods for forming a PEDOT film by ink-jet printing using the PEDOT ink described in example 4, the method comprising the steps of:
(1) measuring 1.00 ml of isopropanol, adding the isopropanol into 9.00 ml of PEDOT aqueous solution, and uniformly stirring and mixing to form printable PEDOT ink;
(2) processing an isolation column pattern on a substrate of a printing system: spin-coating photoresist on an ITO glass substrate by using a spin coater (the rotating speed in the spin coating process is 2100rpm), heating on a hot table at 165 ℃ for 4min, cooling at room temperature, and then carrying out ultraviolet exposure treatment by using a photoetching machine for 65 s; heating on a heating table at 110 ℃ for 4min, cooling at room temperature, developing for 30-40 s, washing with deionized water, and drying with nitrogen to obtain an isolation column pattern;
the width of the obtained isolation columns is 50 μm, the width of the groove between the isolation columns is 200 μm (the height is 2.3 μm before plasma etching and 1.8 μm after plasma etching);
(3) performing oxygen plasma treatment on the substrate with the isolating column pattern, and then performing carbon tetrafluoride plasma treatment, wherein the oxygen plasma treatment conditions are as follows: oxygen flow rate is 28sccm/s, power is 100w, time is 150s, and carbon tetrafluoride plasma processing conditions are as follows: the flow rate of carbon tetrafluoride is 98sccm/s, the power is 150w, and the time is 90 s;
after the treatment is finished, obtaining a substrate with the surface water contact angle of 110 degrees and the water contact angle of 25 degrees in an ITO area (anode area) of the organic light-emitting display pixel;
(4) filtering the PEDOT ink prepared in the step (1) by adopting a 0.2-micrometer nylon microporous filter membrane, filling the filtered PEDOT ink into an ink-jet printing system, then printing the PEDOT ink on a hydrophilic organic light-emitting display pixel area on a substrate in an aligning way, and controlling the ratio of the thickness of a printed ink layer to the height of an isolation column to be (3-7): 1; evaporating the printing ink to generate gel, drying (heating for 4min at 200 ℃) to obtain a PEDOT film;
the films obtained in this example were tested according to the data acquisition method described in fig. 5: the thickness fluctuation of the PEDOT film is within 9nm, as shown by curve 4 in figure 6 (the ratio of the thickness of the printed ink layer to the height of the isolation column is controlled to be (3-7): 1).
Comparative examples
(1) Taking commercial PEDOT aqueous solution as ink;
(2) performing oxygen plasma treatment on the substrate with the isolating column pattern, and then performing carbon tetrafluoride plasma treatment, wherein the oxygen plasma treatment conditions are as follows: oxygen flow rate is 28sccm/s, power is 100w, and time is 210 s; the carbon tetrafluoride plasma treatment conditions are as follows: the flow rate of carbon tetrafluoride is 98sccm/s, the power is 150w, the time is 60s, and a substrate with the surface water contact angle of the isolation column of 90 degrees and the water contact angle of the ITO area of the organic light-emitting display pixel of 15 degrees is obtained;
(3) filtering the PEDOT ink prepared in the step (1) by adopting a 0.2-micrometer nylon microporous filter membrane, filling the filtered PEDOT ink into an ink-jet printing system, then printing the PEDOT ink on an ITO (indium tin oxide) area of a hydrophilic organic light-emitting display pixel on a substrate in an aligning way, and controlling the ratio of the amount of the printing ink to the height of an isolation column after plasma treatment to be (3-7): the results show that the PEDOT film thickness fluctuates within 22nm, as shown by curve 5 in fig. 6, and the height fluctuations are significantly greater than those obtained with the inks of the present invention.
Therefore, the film obtained by the ink in the process of preparing the hole injection layer by ink-jet printing has small fluctuation and uniform thickness, the problem of nonuniform thickness of the prepared film is effectively solved, the coffee ring effect is avoided, the height of the isolation column can be matched with a plurality of functional layers, and the problem of nonuniform thickness of films of other functional layers is avoided. Simple preparation, easy control, good stability and good application prospect.

Claims (2)

1. The application of the ink for the ink-jet printing hole injection layer in organic light-emitting display is characterized in that the ink is prepared from the following raw materials in percentage by volume: 90-97.5% of PEDOT aqueous solution and 2.5-5% of isopropanol; the surface tension of the ink is 40-51 mN/m; the method of ink-jet printing with the ink comprises the following steps:
(1) preparing raw materials of isopropanol and a PEDOT aqueous solution according to a required proportion, and uniformly mixing the isopropanol and the PEDOT aqueous solution to form PEDOT ink;
(2) processing an isolation column pattern on a substrate, which comprises the following specific processes: spin-coating photoresist on an ITO glass substrate by using a spin coater, carrying out ultraviolet exposure treatment by using a photoetching machine, then carrying out development, flushing by using deionized water, and drying by using nitrogen to obtain an isolation column pattern; the width of the obtained isolation columns is 50 μm, and the width of the groove between the isolation columns is 200 μm; the height of the isolation column is 2.0-2.5 mu m;
(3) performing oxygen plasma treatment on the substrate with the processed isolation column pattern, and then performing carbon tetrafluoride plasma treatment on the substrate to obtain a substrate with a hydrophobic isolation column surface and a hydrophilic region of the organic light-emitting display pixel; the water contact angle of the surface of the treated isolation column is more than 90 degrees; a water contact angle of an area of the organic light emitting display pixels on the substrate is less than 25 °;
(4) filtering the PEDOT ink obtained in the step (1) by using a 0.2-micrometer nylon microporous filter membrane, filling the obtained product into an ink-jet printing system, and then printing the PEDOT ink on a hydrophilic organic light-emitting display pixel area on a substrate, wherein the ratio of the thickness of the ink layer printed in the area to the height of the isolation column after plasma treatment is (3-7): 1; and (3) evaporating the gel, heating the PEDOT ink for 3-5 min at a 200 ℃ hot stage, and drying to obtain a PEDOT film with uniform thickness, thereby completing the ink-jet printing of the ink.
2. The use according to claim 1, wherein the oxygen plasma treatment in step (3) is performed at an oxygen flow rate of 28sccm/s, a power of 100w, and a time of 150s-210 s; the flow rate of carbon tetrafluoride in the carbon tetrafluoride plasma treatment is 98sccm/s, the power is 150w, and the time is 60s-90 s.
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1436028A (en) * 2002-10-23 2003-08-13 清华大学 Organic electroluminescent device and producing method thereof
CN1897326A (en) * 2005-07-11 2007-01-17 大日本印刷株式会社 Gravure plate, method for forming light-emitting layer or hole-injection layer using the same, and organic light-emitting device
CN102293055A (en) * 2009-01-22 2011-12-21 住友化学株式会社 Ink-jet printing ink for organic electroluminescent element, and process for production of organic electroluminescent element
CN103794729A (en) * 2014-01-20 2014-05-14 中国科学院长春应用化学研究所 Large-area polymer solar cell and method for preparing active layer of large-area polymer solar cell
CN108417736A (en) * 2018-01-29 2018-08-17 天津大学 A kind of preparation method of transition metal oxide as hole injection layer

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1436028A (en) * 2002-10-23 2003-08-13 清华大学 Organic electroluminescent device and producing method thereof
CN1897326A (en) * 2005-07-11 2007-01-17 大日本印刷株式会社 Gravure plate, method for forming light-emitting layer or hole-injection layer using the same, and organic light-emitting device
CN102293055A (en) * 2009-01-22 2011-12-21 住友化学株式会社 Ink-jet printing ink for organic electroluminescent element, and process for production of organic electroluminescent element
CN103794729A (en) * 2014-01-20 2014-05-14 中国科学院长春应用化学研究所 Large-area polymer solar cell and method for preparing active layer of large-area polymer solar cell
CN108417736A (en) * 2018-01-29 2018-08-17 天津大学 A kind of preparation method of transition metal oxide as hole injection layer

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