Transparent electrode composition, transparent electrode and preparation method and application thereof

Abstract

The invention discloses a transparent electrode composition, a transparent electrode and a preparation method and application of the transparent electrode. The transparent electrode composition provided by the invention comprises a PEDOT: PSS dispersion liquid, dimethyl sulfoxide, a water-based silane coupling agent and a surfactant. The transparent electrode prepared from the transparent electrode composition has excellent stability, adhesive force and light transmittance and low square resistance. The transparent conductive layer can be used for replacing an existing ITO thin film to serve as the transparent conductive layer of the electrowetting display device. After voltage is applied for a long time, the transparent electrode is not subjected to electrochemical damage, and the service life of the electrowetting display device is greatly prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of electrowetting display devices, and in particular to a transparent electrode composition, a transparent electrode, and a preparation method and application thereof. Background Art

[0002] Transparent conductive film (TCF) is a special material with optical transparency and conductivity, also known as transparent electrode. TCF is an important component of many modern devices, including solar cells, organic light-emitting diodes (OLEDs), liquid crystal displays (LCDs), transparent heaters (THs), reflective electronic paper or smart windows. Traditional transparent conductive films are mainly composed of transparent conductive oxides (TCOs), such as indium tin oxide (ITO). Electrowetting display (EWD) technology uses the competition between electrowetting force and liquid interfacial tension to control the contraction and spread of color inks, thereby realizing pixel switching and grayscale regulation, and obtaining the effect of display color switching.

[0003] The existing technology mainly uses ITO thin film as a transparent conductive layer, and its preparation method has high requirements on production equipment and production conditions. More importantly, in electrowetting display devices, since the electrowetting display principle requires voltage to be applied between the conductive substrates to control the switching of pixels, the ITO conductive film will undergo electrochemical reactions and be damaged after applying voltage for a long time, which affects the service life of the electrowetting display device.

[0004] Therefore, there is an urgent need to develop a new transparent electrode composition to replace the ITO transparent electrode. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the first aspect of the present invention provides a transparent electrode composition, and a transparent electrode prepared from the transparent electrode composition has excellent stability, adhesion, transmittance and sheet resistance.

[0006] The second aspect of the present invention also provides a transparent electrode.

[0007] The third aspect of the present invention also provides a method for preparing a transparent electrode.

[0008] The fourth aspect of the present invention also provides an application of a transparent electrode.

[0009] According to a first aspect of the present invention, an embodiment provides a transparent electrode composition, including a PEDOT:PSS dispersion, dimethyl sulfoxide, an aqueous silane coupling agent and a surfactant.

[0010] The transparent electrode composition according to the embodiment of the present invention has at least the following beneficial effects:

[0011] The transparent electrode prepared by the transparent electrode composition composed of PEDOT:PSS dispersion, dimethyl sulfoxide, aqueous silane coupling agent and surfactant has excellent stability, adhesion, light transmittance and low sheet resistance. It can be used to replace the existing ITO film as the transparent conductive layer of the electrowetting display device. After the voltage is applied for a long time, the transparent electrode of the present invention will not be electrochemically damaged, which greatly improves the service life of the electrowetting display device.

[0012] Furthermore, the present invention uses dimethyl sulfoxide to improve the conductivity of the conductive film after film formation.

[0013] According to some embodiments of the present invention, relative to 100 parts by weight of the PEDOT:PSS dispersion, the content of dimethyl sulfoxide is 3 to 10 parts by weight; the content of the aqueous silane coupling agent is 1 to 3 parts by weight; and the content of the surfactant is 0.8 to 5 parts by weight.

[0014] According to some embodiments of the present invention, relative to 100 parts by weight of the PEDOT:PSS dispersion, the content of dimethyl sulfoxide is 5 to 8 parts by weight; the content of the aqueous silane coupling agent is 1 to 3 parts by weight; and the content of the surfactant is 0.8 to 2 parts by weight.

[0015] According to some embodiments of the present invention, the transparent electrode composition further comprises methanol, whereby methanol promotes the hydrolysis of the silane coupling agent and reduces the sheet resistance of the film.

[0016] According to some embodiments of the present invention, the content of methanol is 4 to 8 parts by weight.

[0017] According to some embodiments of the present invention, the water-based silane coupling agent is selected from at least one of γ-glycidyloxypropyltrimethoxysilane, aminopropyltriethoxysilane, aminoethylaminopropyltrimethoxysilane, and methacryloxypropyltrimethoxysilane.

[0018] According to some embodiments of the present invention, the surfactant is selected from at least one of anionic surfactants, silicone surfactants or nonionic surfactants.

[0019] According to some embodiments of the present invention, the surfactant is selected from at least one of sodium dodecyl sulfate (SDS), polyethylene glycol isooctylphenyl ether (Triton X-100), and polyether-modified organic siloxane.

[0020] According to a second aspect of the present invention, an embodiment provides a transparent electrode, comprising the transparent electrode composition according to the first aspect of the present invention.

[0021] A third aspect of the present invention provides a method for preparing a transparent electrode, comprising the following steps:

[0022] S1, mixing and stirring a PEDOT:PSS dispersion, dimethyl sulfoxide, methanol, an aqueous silane coupling agent and a surfactant to obtain a precursor solution;

[0023] S2. Coating the precursor solution on the surface of the substrate; heating and curing the solution into a film to obtain a transparent electrode.

[0024] According to some embodiments of the present invention, in step S2, the temperature of the heating and curing is 100-135°C.

[0025] According to some embodiments of the present invention, in step S1, the coating includes at least one of spin coating, wire rod coating or drop printing.

[0026] According to some embodiments of the present invention, the substrate includes at least one of glass, polyester film or polyimide film.

[0027] According to some embodiments of the present invention, the substrate is treated by ozone ultraviolet radiation, thereby removing organic pollutants on the substrate surface and also performing surface modification, so that the activated substrate surface has good bonding properties.

[0028] A fourth aspect of the present invention provides an application of the transparent electrode composition or the transparent electrode described above in an electrowetting display device.

[0029] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0031] Figure 1 is a physical picture of the transparent electrode of Example 1 of the present invention;

[0032] Figure 2 These are pictures of the transparent electrode of Example 1 of the present invention and the ITO conductive film of Comparative Example 1 after aging test. DETAILED DESCRIPTION

[0033] The following are specific embodiments of the present invention, and the technical solutions of the present invention are further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0034] Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0035] Some of the raw materials in the present invention are as follows:

[0036] PEDOT:PSS dispersion: purchased from Heraeus, model PH1000.

[0037] Water-based silane coupling agent: γ-glycidyloxypropyltrimethoxysilane; commercially available.

[0038] Surfactant: Polyethylene glycol p-isooctylphenyl ether; commercially available.

[0039] Dimethyl sulfoxide and methanol are commercially available.

[0040] Example 1

[0041] This example provides a transparent electrode composition, the amount of its components is shown in Table 1; the steps of preparing a transparent electrode from the transparent electrode composition are as follows: The prepared transparent electrode is shown in the figure Figure 1 shown.

[0042] Substrate pretreatment: Place the substrate sodium calcium glass in ultrapure water for ultrasonic cleaning for 10 minutes, use N2 to blow dry, then place the substrate in 95% alcohol for ultrasonic cleaning for 10 minutes, and use N2 to blow dry; move the substrate to a UV ozone machine for 10 minutes to complete the substrate pretreatment.

[0043] S1. Add dimethyl sulfoxide to the initial PEDOT:PSS dispersion, mix it on a mechanical shaker for 20 minutes, then add methanol and silane coupling agent, mix it on a mechanical shaker for 20 minutes, and finally add surfactant, mix it on a mechanical shaker for 20 minutes to obtain a precursor solution;

[0044] S2. Fix the substrate soda lime glass in a spin coater, take about 0.2 mL of the precursor solution and place it on the substrate, first spin coat it at a rotation speed of 300 RPM (revolutions per minute) for 10 seconds, then spin coat it at a rotation speed of 2000 RPM for 30 seconds, and then place the substrate on a hot plate at 120°C for 10 minutes to cure it into a film.

[0045] Embodiments 2 to 4

[0046] Examples 2 to 4 provide a series of transparent electrode compositions, the amounts of the components are shown in Table 1; the preparation method of the transparent electrode is the same as that of Example 1.

[0047] Table 1 Components of Examples 1 to 4 (parts by weight)

[0048] Example 1 Example 2 Example 3 Example 4 PEDOT:PSS dispersion 100 100 100 100 Dimethyl sulfoxide 5 3 8 5 Methanol 5 10 4 8 Water-based silane coupling agent 1 0.5 1 1.5 Surfactants 1 5 2 0.8

[0049] Example 5

[0050] This example provides a transparent electrode composition, and the dosage of the components and the preparation method of the transparent electrode are the same as those in Example 1. The difference is that Example 5 does not contain methanol.

[0051] Comparative Examples 1-2

[0052] Comparative Examples 1-2 provide a series of transparent electrode compositions, the amounts of the components are shown in Table 2; the preparation method of the transparent electrode is the same as that of Example 1.

[0053] Table 2 Components of Comparative Examples 1 to 2 (parts by weight)

[0054] Comparative Example 1 Comparative Example 2 PEDOT:PSS dispersion 100 100 Dimethyl sulfoxide — 5 Methanol 5 5 Water-based silane coupling agent 1 — Surfactants 1 1

[0055] Performance Testing

[0056] The transparent electrodes prepared in the examples of the present invention and the comparative examples were subjected to the following tests; the results are shown in Table 3.

[0057] Adhesion: Tested using the method specified in national standard GB-T 9286-1998.

[0058] Light transmittance: Use a spectrometer to test, with the incident light vertically incident on the sample, and test the light transmittance in the visible light band (with 520nm as a reference).

[0059] Sheet resistance: Use a sheet resistance meter to test. The sheet resistance meter test probe contacts the sample vertically to read the sheet resistance test data.

[0060] Table 3 Examples 1 to 5 and Comparative Examples 1 to 2

[0061] Adhesion grade Transmittance (520nm) Sheet resistance (Ω / sq) Example 1 5B 89.5％ 171 Example 2 2B 89.7％ 429 Example 3 5B 89.5％ 211 Example 4 5B 88.9％ 245 Example 5 5B 89.3％ 210 Comparative Example 1 5B 89.1％ MΩ level Comparative Example 2 1B 89.6％ 163

[0062] From the data in Table 3, it can be seen that the silane coupling agent can effectively improve the adhesion of the PEDOT conductive film at an appropriate addition amount. The transmittance of the PEDOT conductive film prepared under the same spin coating parameters and baking conditions is not much different, which shows that the doping precursor solution will not have an adverse effect on the transmittance of the PEDOT conductive film. The addition of dimethyl sulfoxide can effectively improve the conductivity of the PEDOT conductive film and reduce the square resistance of the film. The addition of methanol can promote the hydrolysis of silane, and can also improve the conductivity of the PEDOT conductive film at an appropriate addition amount.

[0063] Furthermore, the present invention provides an encapsulation aging test experiment of the transparent electrode and the ITO conductive film of Example 1: a hydrophobic dielectric layer (800nm; the hydrophobic dielectric layer material is fluorinated polymer Teflon) of the same thickness is spin-coated on the ITO conductive film (purchased from Shenzhen Pinbo Technology Co., Ltd., model TP-120) and the transparent electrode of Example 1 of the present invention, respectively, and then encapsulated with ultrapure water and the same voltage (15V DC voltage) is applied under the same environment for aging for 72 hours. The results are as follows: Figure 2 As shown, Figure 2 (a) is the aging test diagram of ITO conductive film. Figure 2 (b) is a schematic diagram of the aging of the transparent electrode of Example 1 of the present invention; the ITO conductive film is electrochemically damaged, and the transparent electrode of the present invention has better stability in the use environment of the electrowetting display device.

[0064] The above is a detailed description of the embodiments of the present invention, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A transparent electrode composition, characterized in that: The invention comprises a PEDOT:PSS dispersion, dimethyl sulfoxide, an aqueous silane coupling agent and a surfactant.

2. The transparent electrode composition according to claim 1, characterized in that: Relative to 100 parts by weight of the PEDOT:PSS dispersion, the content of the dimethyl sulfoxide is 3 to 10 parts by weight, the content of the water-based silane coupling agent is 1 to 3 parts by weight, and the content of the surfactant is 0.8 to 5 parts by weight.

3. The transparent electrode composition according to claim 1 or 2, characterized in that: The transparent electrode composition further includes methanol, and the content of the methanol is 4 to 8 parts by weight.

4. The transparent electrode composition according to claim 1 or 2, characterized in that: The water-based silane coupling agent is selected from at least one of γ-glycidyloxypropyltrimethoxysilane, aminopropyltriethoxysilane, aminoethylaminopropyltrimethoxysilane or methacryloxypropyltrimethoxysilane.

5. The transparent electrode composition according to claim 1 or 2, characterized in that: The surfactant is selected from at least one of anionic surfactants, silicone surfactants or nonionic surfactants.

6. A transparent electrode, characterized in that: The transparent electrode composition comprises the transparent electrode composition according to any one of claims 1 to 6.

7. The method for preparing a transparent electrode according to claim 6, characterized in that: The steps include: S1. Mix and stir the PEDOT:PSS dispersion, dimethyl sulfoxide, aqueous silane coupling agent and surfactant to obtain a precursor solution; if methanol is present, add it to the precursor solution; S2. Coating the precursor solution on the surface of the substrate; heating and curing the solution into a film to obtain a transparent electrode.

8. The method for preparing a transparent electrode according to claim 7, characterized in that: In step S2, the temperature of the heating and curing is 100-135°C.

9. The method for preparing a transparent electrode according to claim 7, characterized in that: The coating includes at least one of spin coating, wire bar coating or drop printing.

10. Use of the transparent electrode composition according to any one of claims 1 to 5 or the transparent electrode according to claim 6 in an electrowetting display device.

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