High-dielectric-constant flexible dielectric layer and organic / inorganic self-alignment-based low-temperature preparation method and application thereof
By employing a self-aligned low-temperature fabrication method for organic-inorganic stacked dielectric layers, the problems of flexible substrate decomposition caused by high temperatures in metal oxide dielectric films and low dielectric constant of organic dielectric layers were solved, thus achieving low-temperature fabrication and performance improvement of flexible dielectric layers with high dielectric constants.
Patent Information
- Application Number
- CN202511853039.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-10
- Publication Date
- 2026-04-07
AI Technical Summary
In the prior art, the excessively high preparation temperature of metal oxide dielectric films leads to thermal decomposition of the flexible substrate, and the low dielectric constant of the organic dielectric layer results in a large threshold voltage and low mobility for flexible thin-film transistor devices.
A low-temperature preparation method with self-aligned organic and inorganic molecules is adopted. By performing hydrophilic treatment on a glass substrate, polar organic materials such as polyvinyl alcohol are uniformly distributed and combined with hydrophilic groups to form an ordered arrangement. Then, an aqueous solution of metal salt precursor is coated on the organic film to form an organic-inorganic-organic stacked dielectric layer. The dielectric constant is improved by using interfacial polarization.
This method enables the fabrication of flexible dielectric layers with high dielectric constants at low temperatures, improving device performance, reducing fabrication temperature, and solving the problems of low dielectric constant and difficulty in metal salt coating, making it suitable for the development of flexible devices.
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Figure CN121815965A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of printed electronics technology, specifically relating to a high dielectric constant flexible dielectric layer and its organic / inorganic self-aligned low-temperature preparation method and application. Background Technology
[0002] In recent years, mobile display technologies such as mobile phones, smartwatches, and laptops have developed rapidly, and people's requirements for display devices are also increasing. Modern display technology is developing towards the directions that people expect, such as flexibility, portability, and large size. The realization of flexible displays relies on the development of flexible thin-film transistor devices, so the development of flexible devices has also attracted much attention. As an important functional layer of display devices, the dielectric layer is a crucial factor affecting the performance development of devices. To achieve low-cost fabrication, current research focuses on the printing method to prepare metal oxide thin films. However, the current fabrication temperature of metal oxide dielectric films is too high, which easily leads to thermal decomposition of flexible substrates, which is not conducive to the fabrication of flexible devices. To achieve the fabrication of flexible devices, organic materials such as polyvinyl alcohol are often used as dielectric layers. However, due to the low dielectric constant of organic materials, thin-film transistors based on them are often limited by problems such as high threshold voltage and low mobility. Therefore, the performance of organic dielectric layers still needs to be improved. Summary of the Invention
[0003] To address the shortcomings and deficiencies of existing technologies, the primary objective of this invention is to provide a method for preparing a high-dielectric-constant flexible dielectric layer at low temperature based on the self-alignment of organic and inorganic molecules. This invention involves hydrophilically treating a glass substrate, allowing polar organic materials such as polyvinyl alcohol to be uniformly distributed on the substrate and combine with the hydrophilic groups obtained from the hydrophilic treatment to form an ordered arrangement. A precursor aqueous solution is then coated onto the organic film. The aqueous solution carries a metal salt and forms an interface with the polyvinyl alcohol through self-alignment. Due to the principle of interfacial polarization, a high dielectric constant is obtained, such as... Figure 1 As shown (using polyvinyl alcohol and zirconium oxide as examples). Furthermore, this invention uses organic dielectric materials with hydrophilic groups such as hydroxyl or carboxyl groups, such as polyvinyl alcohol, poly(4-vinylphenol), and poly(2-hydroxyethyl methacrylate), which allows for good coating of the precursor aqueous solution of the metal oxide onto the organic material, thereby achieving the purpose of low-temperature preparation.
[0004] Another object of the present invention is to provide a high dielectric constant flexible dielectric layer obtained by the above-described preparation method. This flexible dielectric layer has high stability and can be obtained at a relatively low annealing temperature.
[0005] Another object of the present invention is to provide an application of the above-mentioned high dielectric constant flexible dielectric layer.
[0006] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a high dielectric constant flexible dielectric layer at low temperature based on self-alignment of organic and inorganic molecules, comprising the following steps: (1) Dissolve the organic dielectric material with hydrophilic group in water to obtain an organic precursor solution; dissolve the inorganic metal salt in water to obtain an inorganic precursor solution; (2) After plasma treatment of the substrate, the organic precursor solution is spin-coated onto the substrate and thermally annealed to obtain an organic dielectric layer. (3) Spin-coating an inorganic precursor solution onto an organic dielectric layer and thermally annealing it to obtain an inorganic metal oxide dielectric layer; (4) Spin-coating an organic precursor solution onto an inorganic metal oxide dielectric layer and thermally annealing it to obtain an organic-inorganic-organic stacked dielectric layer.
[0007] Preferably, the hydrophilic organic dielectric material in step (1) includes at least one of polyvinyl alcohol, poly(4-vinylphenol) and poly(2-hydroxyethyl methacrylate).
[0008] Preferably, the concentration of the organic precursor solution in step (1) is 5-10 wt%.
[0009] Preferably, the organic dielectric material with hydrophilic groups described in step (1) is fully dissolved in water by heating at 60-80°C for 1-2 hours to obtain an organic precursor solution.
[0010] Preferably, the inorganic metal salt in step (1) includes at least one of aluminum nitrate, zirconium nitrate, and hafnium nitrate.
[0011] Preferably, the concentration of the inorganic precursor solution in step (1) is 0.1 to 0.4 mol / L.
[0012] Preferably, the substrate in step (2) comprises at least one of glass, quartz, monocrystalline silicon, sapphire, and plastic.
[0013] Preferably, the plasma treatment process in step (2) is as follows: the power is 50-70w, the treatment time is 300-500s, and the atmosphere is a mixture of oxygen and nitrogen, wherein the volume percentage of oxygen is 5-10% and the volume percentage of nitrogen is 90-95%.
[0014] Preferably, the spin coating process in steps (2) to (4) is as follows: the spin coating speed is 3000 to 6000 rpm, and the spin coating time is 30 to 50 seconds each time.
[0015] Preferably, the temperature of the heat annealing in steps (2) to (4) is 100 to 150 °C and the time is 1 to 2 hours.
[0016] Secondly, the present invention provides a high dielectric constant flexible dielectric layer obtained by the above method.
[0017] Thirdly, the present invention provides the application of the above-mentioned high dielectric constant flexible dielectric layer in flexible devices.
[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects: This invention uses water as a solvent, which simplifies impurity removal and requires a low annealing temperature, thus benefiting the development of flexible devices. This is because the glass transition temperature of the flexible substrate limits the temperature during thin film preparation to no more than 300°C. The organic-inorganic-organic stacked structure can solve two problems: First, the low dielectric constant of the organic dielectric layer. Due to the inherent characteristics of organic dielectric materials, organic polymers have low polarity, resulting in a generally low dielectric constant and weak capacitance storage capacity. This invention adds a layer of high-dielectric-constant metal oxide between the organic dielectric layers to increase the dielectric constant of the dielectric layer, thereby improving device performance. In addition, a more considerable dielectric constant is obtained through interface polarization. Second, the difficulty in coating aqueous solutions of metal salts on the substrate. When preparing precursor solutions of metal oxides using water as a solvent, the solution is difficult to coat on glass substrates or gate materials. This invention first spin-coats a layer of organic dielectric material with hydrophilic groups, which makes good contact with the aqueous solution, reducing the contact angle between the metal salt solution and the substrate and improving the spreadability of the metal salt solution. Water as the main solvent has advantages such as easy removal and low-temperature evaporation, which can effectively reduce the annealing temperature required to prepare metal oxide thin films, thus better meeting the requirements of flexible devices. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of a stacked dielectric layer structure.
[0020] Figure 2 The capacitance and current tests are shown in Example 1 and Comparative Example 1 (a) and (b) respectively.
[0021] Figure 3 For Comparative Example 2, (a) capacitance and (b) current tests are performed. Detailed Implementation
[0022] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.
[0023] Unless otherwise specified in the embodiments of this invention, the conditions shall be performed according to conventional conditions or conditions recommended by the manufacturer. All raw materials and reagents used, unless otherwise specified, are commercially available conventional products.
[0024] Example 1 This embodiment describes a method for preparing a high-dielectric-constant organic dielectric layer at low temperature based on a multilayer structure of organic materials and inorganic metal oxides. The specific steps for preparing the precursor solution and the thin film are as follows: (1) Select polyvinyl alcohol, a dielectric layer material with hydrophilic groups, dissolve it in water at a concentration of 5wt%, and heat it at 75℃ for 1h to obtain a stable organic precursor solution; select zirconium nitrate as solute, water as solvent at a concentration of 0.3mol / L, and stir the prepared solution on a magnetic stirrer for one day to obtain a transparent and clear inorganic precursor solution. (2) After the glass substrate is subjected to plasma treatment for 300s in a mixed gas atmosphere of 70w, 5% oxygen and 95% nitrogen by volume, the organic precursor solution is spin-coated onto the glass substrate. The number of spin-coating times is 1. The spin-coating speed is 5000rpm for 40s. After spin-coating, annealing is performed at 100℃ for 1h to obtain an organic dielectric thin film. (3) Spin-coat the inorganic precursor solution onto the organic dielectric layer obtained in step (2) once; spin-coat at a high speed of 5000 rpm for 40 seconds; annealing at 100°C for 1 hour after spin-coating to obtain the inorganic dielectric thin film. (4) Spin-coat the organic precursor solution onto the inorganic dielectric layer obtained in step (3) once. The spin-coating speed is 5000 rpm for 40 seconds. After spin-coating, perform annealing treatment at 100°C for 1 hour to obtain an organic-inorganic-organic stacked dielectric layer.
[0025] Comparative Example 1 This embodiment describes a method for preparing a high-dielectric-constant organic dielectric layer at low temperature based on a multilayer structure of organic materials and inorganic metal oxides. The specific steps for preparing the precursor solution and the thin film are as follows: (1) Select polyvinyl alcohol, a dielectric layer material with hydrophilic groups, dissolve it in water at a concentration of 5wt%, and heat it at 75℃ for 1h to obtain a stable organic precursor solution. (2) After the glass substrate is subjected to plasma treatment for 300s in a mixed gas atmosphere of 70w, 5% oxygen and 95% nitrogen by volume, the organic precursor solution is spin-coated onto the glass substrate. The number of spin-coating times is 1. The spin-coating speed is 5000rpm for 40s. After spin-coating, annealing is performed at 100℃ for 1h to obtain an organic dielectric thin film. (3) Spin-coat the organic precursor solution onto the organic dielectric layer obtained in step (2) once. The spin-coating speed is 5000 rpm for 40 seconds. After spin-coating, perform annealing treatment at 100°C for 1 hour to obtain an organic-organic stacked dielectric layer.
[0026] Experimental results are as follows Figure 2 As shown, compared to Comparative Example 1, Example 1 increased the film capacitance from 2.5 × 10⁻⁶ by adding a zirconium oxide layer. -11 The horizontal dimension has increased to 1.5 × 10. -10 The leakage current increased by about 6 times, while the leakage current did not change significantly.
[0027] Comparative Example 2 This embodiment describes a method for preparing a composite dielectric layer based on a mixed structure of organic and inorganic metal oxides. The specific steps for preparing the precursor solution and the thin film are as follows: (1) Polyvinyl alcohol, a dielectric layer material with hydrophilic groups, was selected, and zirconium nitrate was selected as a solute. The two were dissolved together in water. The concentration of polyvinyl alcohol in water was 5wt%, and the concentration of zirconium nitrate in water was 0.3mol / L. The solution was heated at 75℃ for 1h to obtain a stable composite precursor solution. After stirring on a magnetic stirrer for one day, a transparent and clear composite precursor solution was obtained. (2) After the glass substrate is subjected to plasma treatment for 300s in a mixed gas atmosphere of 70w, 5% oxygen and 95% nitrogen by volume, the composite precursor solution is spin-coated onto the glass substrate once. The spin-coating speed is 5000rpm for 40s. After spin-coating, annealing is performed at 100℃ for 1h to obtain the composite dielectric film.
[0028] Experimental results are as follows Figure 3 As shown, the capacitance of the prepared hybrid dielectric layer is improved, but the improvement is small, and the zirconium oxide introduced by the hybrid layer will act as a defect, leading to an increase in leakage current.
[0029] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A method for preparing a high-dielectric-constant flexible dielectric layer at low temperature based on self-alignment of organic and inorganic molecules, characterized in that, Includes the following steps: (1) Dissolve the organic dielectric material with hydrophilic groups in water to obtain an organic precursor solution; Inorganic metal salts are fully dissolved in water to obtain inorganic precursor solutions; (2) After plasma treatment of the substrate, the organic precursor solution is spin-coated onto the substrate and thermally annealed to obtain an organic dielectric layer. (3) Spin-coating an inorganic precursor solution onto an organic dielectric layer and thermally annealing it to obtain an inorganic metal oxide dielectric layer; (4) Spin-coating an organic precursor solution onto an inorganic metal oxide dielectric layer and thermally annealing it to obtain an organic-inorganic-organic stacked dielectric layer.
2. The method according to claim 1, characterized in that, The organic dielectric material with hydrophilic groups in step (1) includes at least one of polyvinyl alcohol, poly(4-vinylphenol) and poly(2-hydroxyethyl methacrylate).
3. The method according to claim 1, characterized in that, The concentration of the organic precursor solution in step (1) is 5-10 wt%.
4. The method according to claim 1, characterized in that, The inorganic metal salt in step (1) includes at least one of aluminum nitrate, zirconium nitrate and hafnium nitrate.
5. The method according to claim 1, characterized in that, The concentration of the inorganic precursor solution in step (1) is 0.1 to 0.4 mol / L.
6. The method according to claim 1, characterized in that, The spin coating process described in steps (2) to (4) is as follows: the spin coating speed is 3000 to 6000 rpm, and the spin coating time is 30 to 50 seconds each time.
7. The method according to claim 1, characterized in that, The annealing temperatures in steps (2) to (4) are all 100 to 150 °C, and the annealing times are all 1 to 2 hours.
8. The method according to claim 1, characterized in that, The plasma treatment process in step (2) is as follows: the power is 50-70W, the treatment time is 300-500s, and the atmosphere is a mixture of oxygen and nitrogen, wherein the volume percentage of oxygen is 5-10% and the volume percentage of nitrogen is 90-95%. And / or, the substrate in step (2) includes at least one of glass, quartz, monocrystalline silicon, sapphire and plastic.
9. A high dielectric constant flexible dielectric layer obtained by the method according to any one of claims 1 to 8.
10. The application of the high dielectric constant flexible dielectric layer as described in claim 9 in flexible devices.