A SnO2-based composite target, its preparation method and application

Abstract

This invention discloses a SnO2-based composite target, its preparation method, and its applications. The SnO2-based composite target of this invention comprises the following components by mass percentage: SnO2 content of 91.5%–95.5%, silver content of 3%–5%, copper oxide content of 1%–2%, and lanthanum oxide content of 0.5%–1.5%, with the sum of all components being 100%. This invention systematically improves the conductivity, mechanical properties, and sintering performance of SnO2 by introducing synergistic co-doping of Ag, Cu, and La. It further improves the density of the target material and reduces its resistivity.

Description

Technical Field

[0001] This invention relates to the field of target preparation technology, and in particular to a SnO2-based composite target, its preparation method, and its application. Background Technology

[0002] Tin oxide (SnO2)-based TCO thin films have become a research hotspot due to their abundant raw material reserves, non-toxicity, and good chemical stability. Tin dioxide (SnO2) has attracted considerable attention for its excellent optical transparency, good chemical stability, and electrical properties, showing broad application prospects, especially in cutting-edge technology fields such as energy, environmental protection, information storage, and optoelectronics. However, despite the appealing natural properties of SnO2, it still faces many challenges under high-performance requirements, including sintering difficulties, insufficient conductivity, and limited mechanical properties.

[0003] Therefore, it is necessary to develop a SnO2-based composite target. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, the first aspect of the present invention proposes a SnO2-based composite target material, which can improve the sintering performance and electrical properties of SnO2 target materials.

[0005] A second aspect of the present invention also provides a method for preparing a SnO2-based composite target.

[0006] A third aspect of the present invention also provides an application of SnO2-based composite target material.

[0007] The SnO2-based composite target provided according to a first aspect embodiment of the present invention comprises the following components by mass percentage:

[0008] The SnO2 content is 91.5%–95.5%, the silver content is 3%–5%, the copper oxide content is 1%–2%, and the lanthanum oxide content is 0.5%–1.5%, with the sum of the amounts of all components being 100%.

[0009] The SnO2-based composite target material according to embodiments of the present invention has at least the following beneficial effects:

[0010] In related technologies, the sintering of SnO2 usually requires extremely high temperatures to achieve material densification, which not only consumes a lot of energy, but may also lead to excessive grain growth, thereby impairing the conductivity and optical transparency of the material.

[0011] This invention systematically improves the conductivity, mechanical properties, and sintering performance of SnO2 by introducing synergistic co-doping of Ag, Cu, and La. It further increases the target density and reduces the target resistivity. The target density is 6.74 g / m³. 3 ~6.86g / m3 Between; target resistivity 7.07×10 -4 Ω·cm~9.82×10 -4 Between Ω·cm.

[0012] Throughout the sintering process, Cu acts as a sintering aid, promoting mass transfer and defect repair within the sintered body. Simultaneously, the addition of Ag forms a highly conductive network, while the introduction of La facilitates the stabilization of grain interfaces, thereby effectively controlling grain size and enhancing the thermal shock resistance of the material.

[0013] Specifically, Cu doping plays a crucial role in improving sintering activity. Because CuO generates a liquid phase during sintering, it effectively promotes wetting and rearrangement between SnO2 particles, which is beneficial for material densification and shortening sintering time. This reduces energy consumption and also facilitates the uniform doping of Ag and La. The introduction of Ag not only significantly improves the material's conductivity but also maintains a superior conductive network structure at high temperatures. This is because Ag can form well-conducting pathways in the SnO2 matrix, and its excellent interfacial properties contribute to a more uniform microstructure during sintering.

[0014] Furthermore, the addition of La provides a significant advantage to this invention. As a rare earth element, La exhibits a unique electronic environment and excellent chemical stability when doped into the SnO2 lattice. 3+ The introduction of lanthanum induces a strain effect in the crystal lattice, which helps to fix oxygen vacancies in the lattice, thereby increasing the electron density of the crystal, improving conductivity, and effectively suppressing grain growth at high temperatures, resulting in a significant improvement in the mechanical properties of the sintered body. The addition of lanthanum also helps to reduce phase transformation and grain boundary migration during thermal cycling, thereby enhancing the thermal stability of the sintered body.

[0015] According to some embodiments of the present invention, the silver has a particle size of 20-30 nm.

[0016] According to some embodiments of the present invention, the specific surface area of ​​the SnO2 is 10 m². 2 / g~25m 2 / g.

[0017] The method for preparing the SnO2-based composite target according to the second aspect embodiment of the present invention includes the following steps:

[0018] S1. SnO2, silver, copper oxide, lanthanum oxide, binder and plasticizer are mixed to obtain a mixed powder, which is then ball-milled to obtain the mixed powder;

[0019] S2. Press the mixed powder into a blank to obtain a green body;

[0020] S3. The green body is degreased, sintered, and cooled to obtain the green body.

[0021] According to some embodiments of the present invention, in step S2, the pressure of the pressing molding is 100MPa to 200MPa.

[0022] According to some embodiments of the present invention, the degreasing step includes: heating to 600℃~650℃ and holding at that temperature for 1h~2h.

[0023] According to some embodiments of the present invention, the sintering step is as follows:

[0024] Raise the temperature to 850–900℃ and hold for 5–6 hours; then raise it to 1200–1250℃ and hold for 3–4 hours; then lower the temperature to 1000–1050℃ and hold for 9–10 hours.

[0025] According to some embodiments of the present invention, the adhesive comprises polyvinyl alcohol.

[0026] According to some embodiments of the present invention, the plasticizer comprises polyethylene glycol.

[0027] The third aspect of this invention provides the application of the SnO2-based composite target in the preparation of TCO thin films for photovoltaic heterojunction cells or perovskite cells.

[0028] Therefore, the TCO thin film prepared by sputtering the SnO2-based composite target described in this invention has good light transmittance, low resistivity, and improves battery conversion efficiency.

[0029] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Detailed Implementation

[0030] The following are specific embodiments of the present invention, and the technical solutions of the present invention will be further described in conjunction with the embodiments, but the present invention is not limited to these embodiments.

[0031] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0032] Some of the raw materials used in the embodiments of this invention are as follows:

[0033] SnO2: purity ≥99.99%, particle size 20-40nm, purchased from Qinghe County Ruijiang Metal Materials Co., Ltd.;

[0034] Silver: purity ≥99.99%, particle size 15-35nm, purchased from Xuzhou Jiechuang New Materials Technology Co., Ltd.;

[0035] Copper oxide: purity ≥99.99%, particle size 40-55nm, purchased from Guangzhou Metal Metallurgy (Group) Co., Ltd.

[0036] Lanthanum oxide: purity ≥99.99%, particle size 45-60nm, purchased from Beijing October New Materials Technology Co., Ltd.

[0037] Example 1

[0038] This example provides a SnO2-based composite target material, the component amounts of which are shown in Table 1, and the preparation method is as follows:

[0039] S1. SnO2, silver, copper oxide, lanthanum oxide, polyvinyl alcohol and polyethylene glycol are mixed to obtain a mixed powder, which is then ball-milled. The ball milling is performed using 0.65 mm and 0.30 mm zirconium beads, respectively, and the powder is then spray-dried to obtain a mixed oxide powder.

[0040] S2. Using a rotating target mold, the mixed oxide powder is injected into the mold and formed using WCIP at a pressure of 100MPa-200MPa. After static pressure strengthening, it becomes a target blank.

[0041] S3. Place the green blank obtained in step S2 into a sintering furnace; raise the temperature to 600-650℃ at a heating rate of 1℃ / min-3℃ / min for degreasing, and hold for 1-2 hours. After degreasing, raise the temperature to 850-900℃ at 3℃ / min and hold for 6 hours; raise the temperature to 1200-1250℃ at 1℃ / min and hold for 4 hours; then lower the temperature to 1000-1050℃ at 1℃ / min and hold for 10 hours; after cooling to room temperature, the target material is obtained.

[0042] Examples 2-6

[0043] Examples 2-6 provide a series of SnO2-based composite targets, the amounts of which are shown in Table 1, and the preparation methods are the same as in Example 1.

[0044] Table 1 Examples 1-6 (mass percentage)

[0045] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 <![CDATA[SnO2]]> 91.5 93 93.5 94 95 95.5 silver 5 4 4 3.5 3 3 copper oxide 2 2 1.5 1.5 1 1 Lanthanum oxide 1.5 1 1 1 1 0.5

[0046] Comparative Examples 1-7

[0047] Comparative Examples 1-7 provide a series of SnO2-based targets, the amounts of which are shown in Table 2, and their preparation methods are the same as in Example 1.

[0048] Table 2 Comparative Examples 1-7 (mass percentage)

[0049]

[0050]

[0051] Performance testing

[0052] The targets prepared in Examples 1-6 and Comparative Examples 1-7 of the present invention were tested as follows; the results are shown in Table 3.

[0053] Density: Measured by Archimedes' displacement method.

[0054] Resistivity: The resistivity of the target material is tested using a resistivity meter.

[0055] Table 3 Examples 1-6 and Comparative Examples 1-7

[0056]

[0057] Table 3 shows that: Comparative Example 1, using undoped pure tin oxide, exhibited numerous pores between grains during sintering, resulting in a low target density, excessively high resistivity, and almost no conductivity. Comparative Example 2, through Ag doping, reduced the target resistivity, but the target density remained low. Comparative Example 3, through CuO doping, improved the sintering density and slightly reduced the resistivity, but still failed to achieve the desired effect. Comparative Example 4, doped with La2O3, slightly reduced the resistivity. Comparative Example 5, simultaneously doped with Ag and CuO, significantly improved the target density and further reduced the resistivity, but still failed to achieve the ideal resistance value. Comparative Example 6, simultaneously doped with CuO and La2O3, increased the target density and further reduced the resistivity, indicating that the addition of CuO improved the La doping effect, but still failed to achieve the ideal resistance value. Comparative Example 7, simultaneously doped with Ag, CuO, and La2O3, had excessively high doping levels, causing significant lattice distortion and cracking after sintering.

[0058] Examples 1-6 of this invention simultaneously doped with Ag, CuO, and La2O3, and are confined within the scope of this invention. The co-doping of Ag and Cu improved the density of the target material. Based on this, the doping with La ultimately yielded a sintered body with good density and a further reduction in resistivity compared to the comparative example. The sintered target material exhibits excellent resistivity and density, and the processed target material can be stably used for sputtering coating.

[0059] The present invention has been described in detail above with reference to the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A SnO2-based composite target, characterized in that, Composed of the following components by mass percentage composition: The SnO2 content is 91.5%~95.5%, the silver content is 3%~5%, the copper oxide content is 1%~2%, the lanthanum oxide content is 0.5%~1.5%, and the sum of the amounts of each component is 100%.

2. The SnO2-based composite target material according to claim 1, characterized in that, The silver has a particle size of 20~30 nm.

3. The SnO2-based composite target material according to claim 1, characterized in that, The specific surface area of ​​the SnO2 is 10m². 2 / g~25m 2 / g.

4. The method for preparing the SnO2-based composite target according to any one of claims 1 to 3, characterized in that, Includes the following steps: S1. SnO2, silver, copper oxide, lanthanum oxide, binder and plasticizer are mixed to obtain a mixed powder, which is then ball-milled to obtain the mixed powder; S2. Press the mixed powder into a blank to obtain a green body; S3. The green body is degreased, sintered, and cooled to obtain the green body.

5. The method for preparing the SnO2-based composite target according to claim 4, characterized in that, In step S2, the pressure for pressing and molding is 100 MPa to 200 MPa.

6. The method for preparing the SnO2-based composite target according to claim 4, characterized in that, The degreasing step includes: heating to 600℃~650℃ and holding at that temperature for 1h~2h.

7. The method for preparing the SnO2-based composite target according to claim 4, characterized in that, The sintering steps are as follows: Raise the temperature to 850-900℃ and hold for 5-6 hours; then raise it to 1200-1250℃ and hold for 3-4 hours; then lower the temperature to 1000-1050℃ and hold for 9-10 hours.

8. The method for preparing the SnO2-based composite target according to claim 4, characterized in that, The adhesive includes polyvinyl alcohol.

9. The method for preparing the SnO2-based composite target according to claim 4, characterized in that, The plasticizer includes polyethylene glycol.

10. The application of the SnO2-based composite target according to any one of claims 1 to 3 in the preparation of TCO thin films for photovoltaic heterojunction cells or TCO thin films for perovskite cells.

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