PEDOT: PSS transparent electrode robustness improving method based on patterned metal covering

Abstract

The invention discloses a method for improving the robustness of a PEDOT: PSS transparent electrode based on patterned metal coverage, and the method comprises the following steps: carrying out the patterning of PEDOT: PSS on a quartz plate substrate through photoetching, carrying out the evaporation of a metal film at the part, connected with an external drive, of the PEDOT: PSS electrode, keeping the PEDOT: PSS film state at the other part, and finally removing photoresist to obtain the PEDOT: PSS transparent electrode. And leaving the patterned metal film and the PEDOT: PSS film. According to the method for improving the robustness of the PEDOT: PSS transparent electrode based on the patterned metal coverage, the thickness of the photoresist is moderate, the robustness of the PEDOT: PSS can be obviously improved under the protection of the metal film, and the mechanical strength and the electrical stability of driving connection with external voltage are greatly improved; and the reserved PEDOT: PSS area can realize the effects of light transmission and electric conduction.

Description

Technical Field

[0001] The present invention belongs to the technical field of improving electrode robustness, and in particular relates to a method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal covering. Background Art

[0002] Poly(3,4-ethylenedioxythiophene) / poly(p-styrene sulfonic acid) (PEDOT:PSS) is an organic polymer material with high light transmittance, good thermoelectric properties and electrochemical properties. After being doped with dimethyl sulfoxide (DMSO), the conductivity is improved and it is often used to prepare transparent electrodes. Its patterning method is crucial for the manufacture of electronic devices. PEDOT:PSS thin film electrodes have potential applications in organic optoelectronic devices. For example, they can be used as hole transport layers in solar cells to reduce interface barriers and improve photovoltaic conversion efficiency. In the field of bioelectronics, PEDOT:PSS is used in functional biointerfaces, sensors and stimulators due to its biocompatibility, stability and electroactivity. Flexible transparent electrodes composed of PEDOT:PSS combined with nanometal wires can be used in flexible electrochromic devices and flexible wearable devices, and have excellent bending stability.

[0003] Since PEDOT:PSS film is an organic film with a thickness of hundreds of nanometers, its mechanical strength is poor and it often breaks during the binding process with external drivers. Therefore, it is necessary to enhance its mechanical strength, reduce short circuits, and improve the robustness of electrical connections. The following are several common PEDOT:PSS patterning methods: photolithography patterning, solution processing, laser etching, inkjet printing, etc. Among them, photolithography patterning can produce patterns with extremely small features, while also being able to control the geometry of the features extremely precisely. It can be used to pattern a variety of materials, including glass, quartz sheets, silicon, and even flexible substrates. In contrast, although laser etching can provide higher precision and flexibility, it may not be as good as photolithography in large-area patterning and cost-effectiveness. Solution processing and inkjet printing technologies are limited in accuracy and resolution, and require additional process steps to achieve the desired pattern.

[0004] Robustness is used to describe the stability and reliability of a system, model or process in the face of changes or interference. PEDOT:PSS film may be damaged when connected to external electrodes through a binding machine or when facing interference such as temperature and vibration, thereby affecting the electrical properties of the overall structure. Therefore, improving its robustness is an important optimization method. Currently, common optimization methods include solution doping modification and metal electrode surface treatment.

[0005] Solution doping is to modify PEDOT:PSS itself by doping nanomaterials, organic surface modifiers, polyhydroxy organics, etc. to enhance the performance of transparent electrodes. However, this method mainly improves the conductivity, thermoelectric properties, transmittance, etc. of transparent electrodes, and has limited effect on enhancing anti-interference and stability.

[0006] The metal electrode surface treatment method is to coat a layer of gold electrode on the substrate, then produce a rough and porous surface through selective iodine etching, and then coat a layer of PEDOT:PSS. This method has 100% stability under strong ultrasonic stability test. However, this method does not directly achieve the patterning of PEDOT:PSS. Additional processes are required later, such as electrochemical modification of the PEDOT:PSS coating surface through cyclic voltammetry to improve its stimulation ability and achieve the patterning effect.

[0007] Therefore, in order to address the above-mentioned problem that the robustness improvement effect is not obvious or additional processes need to be added, the present invention provides a method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage. Summary of the invention

[0008] The purpose of the present invention is to provide a method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage. The thickness of the photoresist is moderate, and the robustness of the PEDOT:PSS can be significantly improved under the protection of the metal film, greatly improving the mechanical strength and the electrical stability of the connection with an external voltage drive; the retained PEDOT:PSS area can achieve the functions of light transmission and conductivity.

[0009] To achieve the above object, the present invention provides a method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage, comprising the following steps:

[0010] S1. Clean the quartz substrate using an ultrasonic cleaner and blow dry it with nitrogen;

[0011] S2, taking out the PEDOT:PSS solution and the dimethyl sulfoxide solution, doping the PEDOT:PSS solution and the dimethyl sulfoxide solution in a certain proportion and stirring them evenly, filtering impurities with a filter tip after stirring evenly, and putting them into a bottle for later use;

[0012] S3, using a coating machine to spin-coat the photoresist onto a clean quartz substrate;

[0013] S4, pre-baking: after spin coating a layer of photoresist, place the quartz substrate on a heating table and keep heating at 100°C for 90 seconds;

[0014] S5, repeating step S3 and step S4, that is, performing spin coating of a second layer of photoresist to increase the thickness of the photoresist, so as to facilitate patterning of the PEDOT:PSS film;

[0015] S6, exposure: placing the quartz substrate with two layers of photoresist spin-coated on the mask, with an exposure time of 16 seconds;

[0016] S7, post-baking: placing the exposed quartz substrate on a heating table and heating it at 100°C for 90 seconds;

[0017] S8, development: put the quartz substrate after post-baking into the developer and soak for 40-50 seconds;

[0018] S9, taking out the quartz substrate in step S8, putting it into deionized water, soaking it to remove excess photoresist, and finally drying the quartz substrate with nitrogen;

[0019] S10, spin-coating the mixed solution put into the bottle in step S2 onto the quartz substrate dried in step S9 by a coating machine;

[0020] S11, using a heating table to heat the quartz substrate in step S10 at a temperature of 90° C. for 3-5 minutes;

[0021] S12, copper plating: using a vacuum evaporation machine, vacuum evaporation is performed on the quartz substrate coated with photoresist and PEDOT:PSS on one side in step S11;

[0022] S13, removing the photoresist: after the copper plating is completed, the quartz substrate is placed in a beaker containing acetone and soaked for more than 12 hours; then, the beaker containing acetone and the quartz substrate is shaken several times with low power by an ultrasonic cleaning machine, each time for 3-6 seconds, until the pattern is clear and obvious;

[0023] S14. Obtain a sample with clear PEDOT:PSS and copper film patterns, dry it with nitrogen, and then seal it for storage.

[0024] Preferably, in step S1, the quartz substrate is cleaned by shaking with deionized water, ethanol and isopropanol for 10 minutes in sequence.

[0025] Preferably, in step S2, the PEDOT:PSS solution and the dimethyl sulfoxide solution are doped in a volume ratio of 100:15.

[0026] Preferably, in step S3, the rotation speed of the glue spreader is maintained at 2000 rpm, and the rotation time is 40 seconds.

[0027] Preferably, in step S6, when the substrate on which two layers of photoresist are spin-coated is placed on the mask, the side of the quartz substrate coated with the photoresist is brought into close contact with the mask.

[0028] Preferably, in step S10, the coating is performed by spin coating on a quartz substrate having a photoresist on one side thereof through a coating machine, the rotation speed of the coating machine is 3000-4000 rpm, and the time is 40 seconds.

[0029] Beneficial effects of the present invention:

[0030] (1) The present invention increases the thickness of the photoresist, and the thickness of the photoresist is moderate, so that when the photoresist is finally removed, a PEDOT:PSS and a copper film with a clear pattern can be obtained at one time; it has the advantages of large area, rapid prototyping, and simple process;

[0031] (2) By coating a layer of copper on the surface of the PEDOT:PSS film, the robustness of PEDOT:PSS as a transparent electrode is improved. Compared with the traditional method of only having a PEDOT:PSS pattern electrode, the present invention can greatly improve the mechanical strength and electrical stability of the connection with an applied voltage drive; reduce film scratches and damage, and improve device yield;

[0032] (3) The method of the present invention is simple in process and does not add other processes except the key photolithography and copper plating processes; and the present invention is also effective for a single layer of PEDOT:PSS pattern, and only the copper plating step needs to be omitted;

[0033] (4) The method of the present invention has fast molding speed, multiple samples can be produced at one time, the preparation area is large, and the pattern is formed in one go.

[0034] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 A diagram of a PEDOT:PSS and copper double-layer film according to an embodiment of a method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage of the present invention;

[0036] Figure 2 This is a PEDOT:PSS single-layer film diagram of an embodiment of a method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage according to the present invention;

[0037] Figure 3 A PEDOT:PSS single layer diagram of Example 1 of a method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage according to the present invention;

[0038] Figure 4A transition region diagram of a PEDOT:PSS and copper double-layer pattern in Example 1 of a method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage according to the present invention;

[0039] Figure 5 The PEDOT:PSS single-layer pattern of Embodiment 2 of the method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage of the present invention;

[0040] Figure 6 This is a joint display diagram of the PEDOT:PSS and copper double-layer patterns of Example 2 of a method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage of the present invention. DETAILED DESCRIPTION

[0041] The technical solution of the present invention is further described below through the accompanying drawings and embodiments.

[0042] Unless otherwise defined, technical or scientific terms used in the present invention shall have the common meanings understood by one having ordinary skills in the field to which the present invention belongs.

[0043] Embodiment 1

[0044] A method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage comprises the following steps:

[0045] S1. Clean the quartz substrate with an ultrasonic cleaner, shake it with deionized water, ethanol, and isopropanol for 10 minutes in sequence, and blow it dry with nitrogen.

[0046] S2. Take out the PEDOT:PSS solution and the dimethyl sulfoxide solution, mix the PEDOT:PSS solution and the dimethyl sulfoxide solution in a volume ratio of 100:15 and stir them evenly. After stirring evenly, use a filter to filter out impurities and put them into a bottle for later use.

[0047] S3, using a coating machine to spin-coat the photoresist on the clean quartz substrate. The rotation speed of the coating machine is maintained at 2000 rpm, and the spinning time is 40 seconds.

[0048] S4, pre-baking: After spin coating a layer of photoresist, place the quartz substrate on a heating table and keep heating at 100°C for 90 seconds.

[0049] S5. Repeat step S3 and step S4, that is, spin-coat a second layer of photoresist to increase the thickness of the photoresist, so as to facilitate the patterning of the PEDOT:PSS film.

[0050] S6. Exposure: Place the quartz wafer substrate with two layers of photoresist spin-coated on the mask, and put the side of the quartz wafer substrate coated with photoresist close to the mask. The exposure time is 16 seconds.

[0051] S7, post-baking: place the exposed quartz substrate on a heating table and heat it at 100° C. for 90 seconds.

[0052] S8, development: put the quartz substrate after post-baking into the developer and soak for 40 seconds.

[0053] S9, taking out the quartz substrate in step S8, putting it into deionized water, soaking it to remove excess photoresist, and finally drying the quartz substrate with nitrogen.

[0054] S10, the mixed solution put into the bottle for standby use in step S2 is spin-coated on the photoresist side of the quartz substrate dried in step S9 by a coating machine at a rotation speed of 4000 rpm for 40 seconds.

[0055] S11, using a heating stage to heat the quartz substrate in step S10 at a temperature of 90° C. for 4 minutes.

[0056] S12, copper plating: using a vacuum evaporation machine, vacuum evaporation is performed on the quartz substrate coated with the photoresist and PEDOT:PSS on one side in step S11.

[0057] S13, photoresist removal: After copper plating is completed, the quartz substrate is placed in a beaker containing acetone and soaked for more than 12 hours. Then, the beaker containing acetone and the quartz substrate is shaken several times with low power using an ultrasonic cleaner for 5 seconds each time until the pattern is clear and obvious.

[0058] S14. Obtain a sample with clear PEDOT:PSS and copper film patterns, dry it with nitrogen, and then seal it for storage.

[0059] The results are as follows Figure 1-4 As shown, in the straight line pattern, whether it is a PEDOT:PSS single-layer film, a PEDOT:PSS and copper double-layer film, or the transition area between the two patterns, the pattern is clearly visible, and the lines are discrete without adhesion or missing.

[0060] Embodiment 2

[0061] A method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage comprises the following steps:

[0062] S1. Clean the quartz substrate with an ultrasonic cleaner, shake it with deionized water, ethanol, and isopropanol for 10 minutes in sequence, and blow it dry with nitrogen.

[0063] S2. Take out the PEDOT:PSS solution and the dimethyl sulfoxide solution, mix the PEDOT:PSS solution and the dimethyl sulfoxide solution in a volume ratio of 100:15 and stir them evenly. After stirring evenly, use a filter to filter out impurities and put them into a bottle for later use.

[0064] S3, using a coating machine to spin-coat the photoresist on the clean quartz substrate. The rotation speed of the coating machine is maintained at 2000 rpm, and the spinning time is 40 seconds.

[0065] S4, pre-baking: After spin coating a layer of photoresist, place the quartz substrate on a heating table and keep heating at 100°C for 90 seconds.

[0066] S5. Repeat step S3 and step S4, that is, spin-coat a second layer of photoresist to increase the thickness of the photoresist, so as to facilitate the patterning of the PEDOT:PSS film.

[0067] S6. Exposure: Place the quartz wafer substrate with two layers of photoresist spin-coated on the mask, and put the side of the quartz wafer substrate coated with photoresist close to the mask. The exposure time is 16 seconds.

[0068] S7, post-baking: place the exposed quartz substrate on a heating table and heat it at 100° C. for 90 seconds.

[0069] S8, development: put the quartz substrate after post-baking into the developer and soak for 50 seconds.

[0070] S9, taking out the quartz substrate in step S8, putting it into deionized water, soaking it to remove excess photoresist, and finally drying the quartz substrate with nitrogen.

[0071] S10, the mixed solution put into the bottle for standby use in step S2 is spin-coated on the photoresist side of the quartz substrate dried in step S9 by a coating machine at a rotation speed of 3000 rpm for 40 seconds.

[0072] S11, using a heating stage to heat the quartz substrate in step S10 at a temperature of 90° C. for 4 minutes.

[0073] S12, copper plating: using a vacuum evaporation machine, vacuum evaporation is performed on the quartz substrate coated with the photoresist and PEDOT:PSS on one side in step S11.

[0074] S13, photoresist removal: After copper plating is completed, the quartz substrate is placed in a beaker containing acetone and soaked for more than 12 hours. Then, the beaker containing acetone and the quartz substrate is shaken several times with low power using an ultrasonic cleaner for 4 seconds each time until the pattern is clear and obvious.

[0075] S14. Obtain a sample with clear PEDOT:PSS and copper film patterns, dry it with nitrogen, and then seal it for storage.

[0076] The results are as follows Figure 5-6 As shown in the figure (the inside of the arc is a blank substrate), this method is also feasible for curved patterns. Whether it is a PEDOT:PSS single-layer film, a blank substrate, a PEDOT:PSS and copper double-layer film, or the transition between the three regions, the patterns are clearly separated and have no obvious distortion or loss.

[0077] Therefore, the present invention adopts the above-mentioned method for improving the robustness of PEDOT:PSS transparent electrode based on patterned metal coverage. The thickness of the photoresist is moderate, and the robustness of PEDOT:PSS can be significantly improved under the protection of the metal film, greatly improving the mechanical strength and electrical stability of the connection with the external voltage drive; the retained PEDOT:PSS area can achieve the functions of light transmission and conductivity.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage, characterized in that: The following steps are involved: S1. Clean the quartz substrate using an ultrasonic cleaner and blow dry it with nitrogen; S2, taking out the PEDOT:PSS solution and the dimethyl sulfoxide solution, doping the PEDOT:PSS solution and the dimethyl sulfoxide solution in a certain proportion and stirring them evenly, filtering impurities with a filter tip after stirring evenly, and putting them into a bottle for later use; S3, using a coating machine to spin-coat the photoresist onto a clean quartz substrate; S4, pre-baking: after spin coating a layer of photoresist, place the quartz substrate on a heating table and keep heating at 100°C for 90 seconds; S5, repeating step S3 and step S4, that is, performing spin coating of a second layer of photoresist to increase the thickness of the photoresist, so as to facilitate patterning of the PEDOT:PSS film; S6, exposure: placing the quartz substrate with two layers of photoresist spin-coated on the mask, with an exposure time of 16 seconds; S7, post-baking: placing the exposed quartz substrate on a heating table and heating it at 100°C for 90 seconds; S8, development: put the quartz substrate after post-baking into the developer and soak for 40-50 seconds; S9, taking out the quartz substrate in step S8, putting it into deionized water, soaking it to remove excess photoresist, and finally drying the quartz substrate with nitrogen; S10, spin-coating the mixed solution put into the bottle in step S2 onto the quartz substrate dried in step S9 by a coating machine; S11, using a heating table to heat the quartz substrate in step S10 at a temperature of 90° C. for 3-5 minutes; S12, copper plating: using a vacuum evaporation machine, vacuum evaporation is performed on the quartz substrate coated with photoresist and PEDOT:PSS on one side in step S11; S13, removing the photoresist: after the copper plating is completed, the quartz substrate is placed in a beaker containing acetone and soaked for more than 12 hours; then, the beaker containing acetone and the quartz substrate is shaken several times with low power by an ultrasonic cleaning machine, each time for 3-6 seconds, until the pattern is clear and obvious; S14. Obtain a sample with clear PEDOT:PSS and copper film patterns, dry it with nitrogen, and then seal it for storage.

2. A method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage according to claim 1, characterized in that: In the step S1, the quartz substrate is cleaned by shaking with deionized water, ethanol and isopropanol for 10 minutes in sequence.

3. The method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage according to claim 1, characterized in that: In the step S2, the PEDOT:PSS solution and the dimethyl sulfoxide solution are mixed and doped in a volume ratio of 100:

15.

4. The method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage according to claim 1, characterized in that: In step S3, the rotation speed of the glue spreader is maintained at 2000 rpm, and the rotation time is 40 seconds.

5. The method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage according to claim 1, characterized in that: In the step S6, when the substrate on which two layers of photoresist are spin-coated is placed on the mask, the side of the quartz substrate coated with the photoresist is closely attached to the mask.

6. The method for improving the robustness of a PEDOT:PSS transparent electrode based on patterned metal coverage according to claim 1, characterized in that: In the step S10, the quartz substrate having the photoresist on one side is spin-coated by a coater, the rotation speed of the coater is 3000-4000 rpm, and the time is 40 seconds.

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