Tin oxide-based target material, preparation method therefor and use thereof

Abstract

The present application relates to the technical field of target materials, and specifically discloses a tin oxide-based target material, a preparation method therefor, and a use thereof. Raw materials for the preparation of the tin oxide-based target material of the present application comprise, in parts by mass, 91-95 parts of tin oxide, 1.5-3.5 parts of tantalum oxide, 1.5-3.5 parts of zinc oxide, 0.5-2 parts of tungsten oxide, and 0.3-1.5 parts of gadolinium oxide, and further comprise a binder and a plasticizer. The present application further provides a preparation method for the tin oxide-based target material and a use of the tin oxide-based target material. The tin oxide-based target material provided by the present application has high density and extremely low resistivity, wherein the density of the tin oxide-based target material is greater than or equal to 6.5 g / m3, and the resistivity thereof is smaller than or equal to 1×10-2Ω·cm. Therefore, the tin oxide-based target material can be suitable for direct-current (DC) magnetron sputtering coating. In addition, due to the advantages of good light transmittance and low resistivity, the tin oxide-based target material of the present application can further improve battery conversion efficiency and can be applied to photovoltaic heterojunction batteries and perovskite batteries.

Description

Tin oxide-based target material, preparation method and application thereof Technical Field

[0001] The present application relates to the field of target material technology, and in particular to a tin oxide-based target material and a preparation method and application thereof. Background Art

[0002] Tin-doped indium oxide (ITO) has high transmittance in the visible light range and very low resistance (usually 1-2×10 -4 Ω·cm), and is considered the most effective material for manufacturing transparent conductive oxide (TCO) thin films. However, due to the very low natural reserves of indium, limited global supply, and fierce competition for resource control, the supply of indium is limited and the cost is high. In particular, the European Union is completely dependent on imported indium, which means that TCO manufacturing within the EU and other low-carbon technologies that rely on indium face serious indium supply risks. Tin, on the other hand, has abundant natural reserves and is relatively cheap, so it is often developed to replace ITO materials. Tin oxide (SnO2) has an optical band gap of approximately 3.5eV-4.0eV. When tin interstitials or oxygen vacancies are present, it exhibits degenerate n-type semiconductor properties. Due to its good chemical stability, high visible light transmittance, and relatively low resistivity, it is widely used in optoelectronic devices such as solar cells and gas sensors.

[0003] SnO2 is an n-type semiconductor whose conductivity depends primarily on electron transfer between the valence band and the conduction band. In pure SnO2, the band gap is large, meaning that electrons require a large amount of energy to transition from the valence band to the conduction band, resulting in a low intrinsic electron concentration. Furthermore, SnO2's tetragonal lattice structure also affects its conductivity. Oxygen vacancies and tin interstitials in the lattice form traps that capture free electrons, further reducing electron mobility and leading to reduced conductivity. Furthermore, in the absence of additives, traditional pressureless sintering is difficult to densify pure SnO2 ceramics. This is related to the sintering mechanism of pure SnO2 ceramics (surface diffusion at low temperatures and evaporation-condensation at high temperatures). The sintered body exhibits a porous, loose, and low-strength structure. When pure SnO2 is used as an electron transport layer, a large number of Sn dangling bonds and oxygen vacancy defects arise, leading to charge recombination and exacerbating interface instability. Therefore, the development of SnO2-based targets, especially those suitable for DC power supply magnetron sputtering coating, has been in the exploratory stage. DC power supply magnetron sputtering coating has become one of the important means of industrial coating due to its advantages such as suppressing arc generation, eliminating film defects, increasing sputtering deposition rate and reducing deposition temperature. However, DC power supply magnetron sputtering coating has very strict requirements on the conductivity of the target material. After applying DC bias and sputtering for a short time, the cations reaching the target surface of the target material with poor conductivity cannot be discharged in time, which will cause the accumulation of positive charge on the target surface. As a result, there is not enough potential difference between the target surface and the plasma (sheath) to incubate the cations reaching the target material, which will eventually cause the plasma to extinguish.

[0004] The above analysis shows that there is a lot of room for improvement in SnO2 targets. Chinese patent CN116813329A optimizes the density and resistivity of SnO2 targets by modifying the doping of Ta2O5, but there is still room for improvement. Chinese patent CN114560692A discloses a method for preparing zinc oxide-doped tin oxide targets by hot pressing and sintering. The prepared target has a high density, but the resistivity of the target system doped with zinc oxide is still high, making it impossible to use a DC power supply for sputtering. Therefore, there is an urgent need to develop a new SnO2-based target and its preparation method, so that it can be used for DC power supply magnetron sputtering coating, and help SnO2-based thin films gradually achieve industrialization. Summary of the Invention

[0005] This application aims to solve at least one of the technical problems existing in the prior art. To this end, this application provides a tin oxide-based target material. The tin oxide-based target material of the present application has the advantages of high density and low resistance, and is suitable for DC power supply magnetron sputtering coating. It can also be used in photovoltaic heterojunction cells and perovskite cells because of its good light transmittance and low resistivity, which can improve the cell conversion efficiency. Compared with ITO targets, it has a lower cost.

[0006] The present application also provides a method for preparing the above-mentioned tin oxide-based target material.

[0007] This application also proposes the application of the above-mentioned tin oxide-based target material.

[0008] In a first aspect of the present application, a tin oxide-based target material is provided, wherein the raw materials for preparation include, by mass, 91-95 parts of tin oxide, 1.5-3.5 parts of tantalum oxide, 1.5-3.5 parts of zinc oxide, 0.5-2 parts of tungsten oxide, and 0.3-1.5 parts of gadolinium oxide.

[0009] According to the specific implementation of the present application, the tin oxide-based target material provided by the present application has at least the following beneficial effects: the tin oxide-based target material of the present application has high density and extremely low resistivity, making it suitable for DC power supply magnetron sputtering coating; in addition, the tin oxide-based target material of the present application also has the advantages of good light transmittance and low resistivity, which can improve the battery conversion efficiency and can be applied to photovoltaic heterojunction batteries and perovskite batteries.

[0010] Compared with ITO targets, tin oxide-based targets have the advantages of abundant natural resources and lower costs. This application achieves the goal of preparing tin oxide-based targets with high density and extremely low resistance by reasonably doping a certain amount of tantalum oxide, zinc oxide, tungsten oxide and gadolinium oxide into a tin oxide-based target.

[0011] When tantalum oxide is doped, since the radius of Ta element is 0.064nm, which is smaller than the radius of Sn element, Ta element can replace the position of Sn element to form Sn (1-x) Ta xO2 solid solution; and because the valence state of Ta element is 5+, which is higher than the valence state of Sn element 4+, the substitution of Ta element will introduce electron holes in SnO2, increase the carrier concentration, and thus improve the conductive properties of SnO2; in addition, the substitution of Ta element will also affect the crystal structure of SnO2, causing its lattice constant to change. As the doping amount of Ta element increases, the substitution of Ta element will make the crystal structure of SnO2 more compact and stable; the substitution of Ta element will also affect the sintering behavior and density of SnO2. As the doping amount of Ta element increases, the sintering temperature of SnO2 will decrease, and the density after sintering will also increase. This is because the substitution of Ta element will promote the grain growth and grain boundary diffusion of SnO2, thereby accelerating the sintering process and reducing the porosity.

[0012] When zinc oxide is doped, due to Zn 2+ The radius of 0.074nm is larger than Sn 4+ The radius of the target is 0.071nm. When Zn replaces Sn, it will cause the adjacent oxygen atoms to detach, forming oxygen vacancies, promoting the development of the SnO2 lattice and generating a large number of electrons, greatly increasing the conductivity. At the same time, within a certain doping range, ZnO and SnO2 react at high temperature to form Zn2SnO4, filling the gaps between the particles, greatly enhancing the sintering and densification of the target material, and achieving sintering assistance for tin oxide-based targets and promoting sintering and densification. The present application also found that excessive ZnO doping can cause the target material to crack and delaminate during sintering. For this reason, the present application provides a suitable doping amount of zinc oxide.

[0013] When tungsten oxide is doped, since W element is an important cationic dopant in tin oxide-based transparent conductive materials, W 6+ Replace Sn 4+ , can enhance the electronic and optical properties of tin oxide; in addition, W 6+ It has the highest valence state among common doping elements and can generate more free electrons; at the same time, the doping of W element also helps to generate more carriers and maintain the structural capacity of tin oxide.

[0014] When gadolinium oxide is doped, the 4f electrons of the Gd ions will form hybrid orbitals with SnO2, thereby increasing the carrier concentration and enabling more electrons to jump to the conduction band; at the same time, the band structure of the doped SnO2 is more compatible with the perovskite layer of the solar cell than pure SnO2, which may lead to higher charge transfer between the electron transport layer and the perovskite interface and less interface recombination; in addition, as a rare earth element, Gd also has strong light absorption, which will change the optical properties of SnO2 and affect its application in optoelectronic devices; although Gd doping can improve the conductivity of SnO2, this application has found that high gadolinium oxide doping concentrations may cause lattice distortion, affecting the stability and other physical properties of SnO2. For this reason, this application provides a suitable doping amount of gadolinium oxide.

[0015] In some embodiments of the present application, the preparation raw materials include, by mass, 91.5-94.5 parts of tin oxide, 2-3 parts of tantalum oxide, 2-3 parts of zinc oxide, 1-1.5 parts of tungsten oxide, and 0.5-1 part of gadolinium oxide.

[0016] In some preferred embodiments of the present application, the preparation raw materials include, by mass, 91.5-93 parts of tin oxide, 2.5-3 parts of tantalum oxide, 2.5-3 parts of zinc oxide, 1-1.5 parts of tungsten oxide, and 0.5-1 part of gadolinium oxide.

[0017] In some embodiments of the present application, the preparation raw materials further include a binder and a plasticizer.

[0018] In some preferred embodiments of the present application, the mass fraction of the binder is 0.4-2.5 parts, and the mass fraction of the plasticizer is 0.1-2 parts.

[0019] In some more preferred embodiments of the present application, the mass fraction of the binder is 0.5-2 parts, and the mass fraction of the plasticizer is 0.5-1.5 parts.

[0020] In some embodiments of the present application, a binder is added to improve the density and mechanical properties of the molded part. The binder is polyvinyl alcohol (PVA), a commonly used binder in the art. Other substances with similar effects can be used as the binder of the present application.

[0021] In some embodiments of the present application, a plasticizer is added to improve the plasticity of the blank. The plasticizer is polyethylene glycol (PEG), a commonly used plasticizer in the art. Other substances with similar effects can be used as the plasticizer of the present application.

[0022] In some embodiments of the present application, the tin oxide, tantalum oxide, zinc oxide, tungsten oxide, and gadolinium oxide are all powders.

[0023] In some preferred embodiments of the present application, the specific surface area of ​​the powder is independently 10 m 2 / g-25m 2 / g.

[0024] In some more preferred embodiments of the present application, the specific surface area of ​​the powder is independently 15 m 2 / g-20m 2 / g.

[0025] In some preferred embodiments of the present application, the tantalum oxide, zinc oxide, tungsten oxide, and gadolinium oxide powders have a D50 of ≤2 μm and a Dmax of ≤10 μm.

[0026] In some embodiments of the present application, the density of the tin oxide-based target is ≥6.5 g / m 3 .

[0027] In some preferred embodiments of the present application, the density of the tin oxide-based target is ≥6.55 g / m 3 .

[0028] In some more preferred embodiments of the present application, the density of the tin oxide-based target is 6.6 g / m 3 -6.75g / m 3 .

[0029] In some embodiments of the present application, the resistivity of the tin oxide-based target is ≤1×10 -2 Ω·cm.

[0030] In some preferred embodiments of the present application, the resistivity of the tin oxide-based target is ≤2×10 -3 Ω·cm.

[0031] The second aspect of the present application provides a method for preparing the tin oxide-based target material as described in the first aspect of the present application, comprising the following steps:

[0032] S1: Mixing, ball milling and spray drying the oxide preparation raw materials;

[0033] S2: static pressing to obtain a green embryo;

[0034] S3: Degreasing, hot pressing and sintering to obtain tin oxide-based target.

[0035] In some embodiments of the present application, a binder and a plasticizer are further added during the ball milling in step S1.

[0036] In some embodiments of the present application, the specific surface area of ​​the mixed powder after spray drying in step S1 is 5m 2 / g-25m 2 / g.

[0037] In some preferred embodiments of the present application, the specific surface area of ​​the mixed powder after spray drying in step S1 is 10m 2 / g-20m 2 / g.

[0038] In some embodiments of the present application, the bulk density of the mixed powder after spray drying in step S1 is 1.1 g / cm 3 -1.6g / cm 3 .

[0039] In some preferred embodiments of the present application, the bulk density of the mixed powder after spray drying in step S1 is 1.3 g / cm 3 -1.5g / cm 3 .

[0040] In some embodiments of the present application, the static pressing method in step S2 is cold isostatic pressing (CIP) at a pressure of 100 MPa-200 MPa.

[0041] In some embodiments of the present application, the degreasing temperature in step S3 is 600° C.-650° C., and the degreasing time is 2 h-3 h.

[0042] In some preferred embodiments of the present application, the degreasing conditions in step S3 are: heating to 600° C.-650° C. in an oxygen atmosphere and degreasing for 2-3 hours. Degreasing in an oxygen atmosphere can prevent the volatilization of tin oxide.

[0043] In some more preferred embodiments of the present application, the degreasing conditions in step S3 are: heating to 600°C-650°C at a heating rate of 1°C / min-3°C / min in an oxygen atmosphere, and degreasing for 2h-3h.

[0044] In some embodiments of the present application, the hot pressing sintering in step S3 includes the following steps:

[0045] S31: heat preservation treatment at 600℃-650℃ for 5h-7h;

[0046] S32: heat preservation treatment at 950℃-1000℃ for 3h-4h;

[0047] S33: heat and pressure maintenance treatment at 1350℃-1400℃ and pressure 25MPa-35MPa for 2h-3h.

[0048] In some preferred embodiments of the present application, the hot pressing sintering in step S3 includes the following steps:

[0049] S31: heating to 600-650°C at a heating rate of 2-4°C / min, and keeping the temperature for 5-7 hours;

[0050] S32: heating to 950-1000°C at a heating rate of 0.5-2°C / min, and keeping the temperature for 3-4 hours;

[0051] S33: heating to 1350-1400°C at a heating rate of 0.1-1°C / min, pressurizing to 25-35 MPa, and maintaining the temperature and pressure for 2-3 hours.

[0052] The third aspect of the present application proposes the application of the tin oxide-based target material described in the first aspect of the present application in coating, batteries, transistors, and display panels.

[0053] In some embodiments of the present application, the coating includes DC power supply magnetron sputtering coating.

[0054] In some embodiments of the present application, the cell includes a photovoltaic heterojunction cell or a perovskite cell.

[0055] Other features and advantages of the present application will be set forth in the following description, and in part will be apparent from the description, or may be learned by practicing the present application. DETAILED DESCRIPTION

[0056] The following will clearly and completely describe the concept and technical effects of this application in conjunction with the embodiments to fully understand the purpose, features and effects of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of this application.

[0057] If the specific conditions are not specified in the specific embodiments, the conventional conditions or the conditions recommended by the manufacturer shall be followed. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0058] Tantalum oxide powder, zinc oxide powder, gadolinium oxide powder and tungsten oxide powder used in the specific embodiment were purchased from Sigma-Aldrich (Shanghai) Trading Co., Ltd.

[0059] Example 1

[0060] This embodiment provides a SnO2-based target material and a preparation method thereof. The raw materials for preparing the SnO2-based target material are composed of the following components in parts by mass:

[0061] 91.5 parts of tin oxide, 3 parts of tantalum oxide, 3 parts of zinc oxide, 1.5 parts of tungsten oxide, 1 part of gadolinium oxide, 1 part of binder, and 1 part of plasticizer.

[0062] Among them, the binder is polyvinyl alcohol (PVA) and the plasticizer is polyethylene glycol (PEG).

[0063] The steps of the SnO2-based target preparation method are as follows:

[0064] 1) Preparation of tin oxide powder:

[0065] Tin oxide powder was prepared by chemical precipitation method, and the specific surface area of ​​the powder was measured to be 18m 2 / g;

[0066] 2) Preparation of mixed oxide powders:

[0067] Prepare corresponding mass fractions of tantalum oxide powder with a purity of ≥99.99%, zinc oxide powder with a purity of ≥99.99%, tungsten oxide powder with a purity of ≥99.99%, and gadolinium oxide powder with a purity of ≥99.99%. Mix these four oxide powders with the tin oxide powder prepared in step 1) and then ball mill them. Use 0.65 mm and 0.30 mm zirconium beads for grinding, add a binder and a plasticizer, and spray dry to obtain a mixed oxide powder. The specific surface area of ​​the mixed powder is measured to be 15 m 2 / g, bulk density is 1.4g / cm 3 ;

[0068] 3) Embryo forming:

[0069] The mixed powder was injected into a rotating target mold and formed by cold isostatic pressing (CIP) at a molding pressure of 150 MPa. After static pressing for 30 minutes at room temperature, a target blank was obtained.

[0070] 4) Degreasing and sintering:

[0071] The formed green blank obtained in step 3) is placed in a hot pressing sintering furnace, evacuated to -90 Pa, and after the pressure stabilizes, oxygen is introduced until the pressure reaches 0 Pa. The temperature is then increased to 610° C. at a rate of 2° C. / min for degreasing, and the temperature is maintained for 2.5 hours. After degreasing, the blank is hot pressed and sintered, with the temperature increased to 640° C. at a rate of 3° C. / min and the temperature maintained for 6 hours; the temperature is increased to 970° C. at a rate of 1° C. / min and the temperature maintained for 3.5 hours; the temperature is increased to 1370° C. at a rate of 0.5° C. / min, and pressurization is started. After the pressure reaches 30 MPa, the temperature and pressure are maintained for 2.5 hours. The blank is then cooled to room temperature to obtain a multinary doped tin oxide target.

[0072] 5) Processing:

[0073] The sintered target material was placed on a lathe for grinding and cutting, and an 800-mesh grinding wheel was used for rough grinding for 6 hours; a 400-mesh grinding wheel was used for fine grinding for 6 hours, and finally a tin oxide-based target material with a relatively smooth surface and suitable size was obtained.

[0074] Example 2

[0075] This embodiment provides a SnO2-based target material and a preparation method thereof. The raw materials for preparing the SnO2-based target material are composed of the following components in parts by mass:

[0076] 92 parts of tin oxide, 3 parts of tantalum oxide, 3 parts of zinc oxide, 1 part of tungsten oxide, 1 part of gadolinium oxide, 0.5 parts of binder, and 0.5 parts of plasticizer.

[0077] Among them, the binder is polyvinyl alcohol (PVA) and the plasticizer is polyethylene glycol (PEG).

[0078] The steps of the SnO2-based target preparation method are as follows:

[0079] 1) Preparation of tin oxide powder:

[0080] Tin oxide powder was prepared by chemical precipitation method, and the specific surface area of ​​the powder was measured to be 18m 2 / g;

[0081] 2) Preparation of mixed oxide powders:

[0082] Prepare corresponding mass fractions of tantalum oxide powder with a purity of ≥99.99%, zinc oxide powder with a purity of ≥99.99%, tungsten oxide powder with a purity of ≥99.99%, and gadolinium oxide powder with a purity of ≥99.99%. Mix these four oxide powders with the tin oxide powder prepared in step 1) and then ball mill them. Use 0.65 mm and 0.30 mm zirconium beads for grinding, add a binder and a plasticizer, and spray dry to obtain a mixed oxide powder. The specific surface area of ​​the mixed powder is measured to be 15 m 2 / g, bulk density is 1.4g / cm 3 ;

[0083] 3) Embryo forming:

[0084] The mixed powder was injected into a rotating target mold and CIP molding was performed at a molding pressure of 120 MPa. After static pressure strengthening at room temperature for 30 minutes, a target blank was obtained.

[0085] 4) Degreasing and sintering:

[0086] The formed green blank obtained in step 3) is placed in a hot pressing sintering furnace, evacuated to -90 Pa, and after the pressure stabilizes, oxygen is introduced until the pressure reaches 0 Pa. The temperature is then increased to 640° C. at a rate of 2.5° C. / min for degreasing, and the temperature is kept at this temperature for 3 hours. After degreasing, the blank is sintered by increasing the temperature to 650° C. at a rate of 3° C. / min and keeping this temperature for 6 hours; increasing the temperature to 960° C. at a rate of 1° C. / min and keeping this temperature for 3.5 hours; increasing the temperature to 1390° C. at a rate of 0.5° C. / min, and starting to apply pressure. After the pressure reaches 30 MPa, the temperature and pressure are maintained at this level for 2.5 hours. The blank is then cooled to room temperature to obtain a multinary doped tin oxide target.

[0087] 5) Processing:

[0088] The sintered target material was placed on a lathe for grinding and cutting, and an 800-mesh grinding wheel was used for rough grinding for 6 hours; a 400-mesh grinding wheel was used for fine grinding for 6 hours, and finally a tin oxide-based target material with a relatively smooth surface and suitable size was obtained.

[0089] Example 3

[0090] This embodiment provides a SnO2-based target material and a preparation method thereof. The raw materials for preparing the SnO2-based target material are composed of the following components in parts by mass:

[0091] 92 parts of tin oxide, 3 parts of tantalum oxide, 3 parts of zinc oxide, 1.5 parts of tungsten oxide, 0.5 parts of gadolinium oxide, 2 parts of binder, and 1.5 parts of plasticizer.

[0092] Among them, the binder is polyvinyl alcohol (PVA) and the plasticizer is polyethylene glycol (PEG).

[0093] The steps of the SnO2-based target preparation method are as follows:

[0094] 1) Preparation of tin oxide powder:

[0095] Tin oxide powder was prepared by chemical precipitation method, and the specific surface area of ​​the powder was measured to be 18m 2 / g;

[0096] 2) Preparation of mixed oxide powders:

[0097] Prepare corresponding mass fractions of tantalum oxide powder with a purity of ≥99.99%, zinc oxide powder with a purity of ≥99.99%, tungsten oxide powder with a purity of ≥99.99%, and gadolinium oxide powder with a purity of ≥99.99%. Mix these four oxide powders with the tin oxide powder prepared in step 1) and then ball mill them. Use 0.65 mm and 0.30 mm zirconium beads for grinding, add a binder and a plasticizer, and spray dry to obtain a mixed oxide powder. The specific surface area of ​​the mixed powder is measured to be 15 m 2 / g, bulk density is 1.4g / cm 3 ;

[0098] 3) Embryo forming:

[0099] Use a rotating target mold to inject the mixed powder into the mold, use CIP molding, the molding pressure is 180MPa, and the target material embryo is obtained after static pressure strengthening;

[0100] 4) Degreasing and sintering:

[0101] The formed green blank obtained in step 3) is placed in a hot pressing sintering furnace, evacuated to -90 Pa, and after the pressure stabilizes, oxygen is introduced until the pressure reaches 0 Pa. The temperature is then increased to 610° C. at a rate of 1.5° C. / min for degreasing, and the temperature is maintained for 3 hours. After degreasing, the blank is sintered by increasing the temperature to 630° C. at a rate of 3° C. / min and maintaining the temperature for 6 hours; increasing the temperature to 990° C. at a rate of 1° C. / min and maintaining the temperature for 3.5 hours; increasing the temperature to 1360° C. at a rate of 0.5° C. / min, and starting to pressurize. After the pressure reaches 30 MPa, the temperature and pressure are maintained for 2.5 hours; and cooling to room temperature to obtain a multinary doped tin oxide target.

[0102] 5) Processing:

[0103] The sintered target material was placed on a lathe for grinding and cutting, and an 800-mesh grinding wheel was used for rough grinding for 6 hours; a 400-mesh grinding wheel was used for fine grinding for 6 hours, and finally a tin oxide-based target material with a relatively smooth surface and suitable size was obtained.

[0104] Example 4

[0105] This embodiment provides a SnO2-based target material and a preparation method thereof. The difference between this embodiment and Example 1 lies only in the difference in the mass fractions of some of the preparation raw material components: 92.5 parts of tin oxide, 1 part of tungsten oxide, and 0.5 part of gadolinium oxide. The remaining raw material components and preparation method are consistent with those of Example 1.

[0106] Example 5

[0107] This embodiment provides a SnO2-based target material and a preparation method thereof. The difference between this embodiment and Example 1 lies only in the difference in the mass fractions of some of the preparation raw material components: 92.5 parts of tin oxide, 2.5 parts of tantalum oxide, and 2.5 parts of zinc oxide. The remaining raw material components and preparation method are consistent with Example 1.

[0108] Example 6

[0109] This embodiment provides a SnO2-based target material and a preparation method thereof. The difference between this embodiment and Example 1 lies only in the difference in the mass fractions of some of the preparation raw material components: 93 parts of tin oxide, 2.5 parts of tantalum oxide, 2.5 parts of zinc oxide, and 1 part of tungsten oxide. The remaining raw material components and preparation method are consistent with those of Example 1.

[0110] Example 7

[0111] This embodiment provides a SnO2-based target material and a preparation method thereof. The difference between this embodiment and Example 1 lies only in the difference in the mass fractions of some of the preparation raw material components: 93.5 parts of tin oxide, 2.5 parts of tantalum oxide, 2.5 parts of zinc oxide, 1 part of tungsten oxide, and 0.5 part of gadolinium oxide. The remaining raw material components and preparation method are consistent with Example 1.

[0112] Example 8

[0113] This embodiment provides a SnO2-based target material and a preparation method thereof. The difference between this embodiment and Example 3 is only the difference in the mass fractions of some of the preparation raw material components: 93.5 parts of tin oxide, 2 parts of tantalum oxide, and 2 parts of zinc oxide. The remaining raw material components and preparation method are consistent with Example 3.

[0114] Example 9

[0115] This embodiment provides a SnO2-based target material and a preparation method thereof. The difference between this embodiment and Example 3 lies only in the difference in the mass fractions of some of the preparation raw material components: 94.5 parts of tin oxide, 2 parts of tantalum oxide, 2 parts of zinc oxide, 1 part of tungsten oxide, and 0.5 parts of gadolinium oxide. The remaining raw material components and preparation method are consistent with Example 3.

[0116] Comparative Example 1

[0117] This comparative example provides a SnO2-based target material and a preparation method thereof. The difference between this comparative example and Example 1 lies only in the difference in the mass fractions of some of the preparation raw material components: 100 parts of tin oxide, without adding tantalum oxide, zinc oxide, tungsten oxide and gadolinium oxide, and the remaining raw material components and preparation method are consistent with Example 1.

[0118] Comparative Example 2

[0119] This comparative example provides a SnO2-based target material and a preparation method thereof. The difference between this comparative example and Example 1 lies only in the difference in the mass fractions of some of the preparation raw material components: 97 parts of tin oxide and 3 parts of tantalum oxide, without adding zinc oxide, tungsten oxide and gadolinium oxide. The remaining raw material components and preparation method are consistent with Example 1.

[0120] Comparative Example 3

[0121] This comparative example provides a SnO2-based target material and a preparation method thereof. The difference between this comparative example and Example 1 lies only in the difference in the mass fractions of some of the preparation raw material components: 97 parts of tin oxide, 3 parts of zinc oxide, and no addition of tantalum oxide, tungsten oxide, and gadolinium oxide. The remaining raw material components and preparation method are consistent with Example 1.

[0122] Comparative Example 4

[0123] This comparative example provides a SnO2-based target material and a preparation method thereof. The difference between this comparative example and Example 1 lies only in the difference in the mass fractions of some of the preparation raw material components: 94 parts of tin oxide, 3 parts of zinc oxide, and 3 parts of tantalum oxide. Tungsten oxide and gadolinium oxide are not added. The remaining raw material components and preparation method are consistent with Example 1.

[0124] Comparative Example 5

[0125] This comparative example provides a SnO2-based target material and a preparation method thereof. The difference between this comparative example and Example 1 lies only in the difference in the mass fractions of some of the preparation raw material components: 92.5 parts of tin oxide, 3 parts of zinc oxide, 3 parts of tantalum oxide, and 1.5 parts of tungsten oxide. No gadolinium oxide is added. The remaining raw material components and preparation method are consistent with Example 1.

[0126] Comparative Example 6

[0127] This comparative example provides a SnO2-based target material and a preparation method thereof. The difference between this comparative example and Example 1 lies only in the difference in the mass fractions of some of the preparation raw material components: 97.5 parts of tin oxide, 1.5 parts of tungsten oxide, and 1 part of gadolinium oxide. Tantalum oxide and zinc oxide are not added. The remaining raw material components and preparation method are consistent with Example 1.

[0128] Comparative Example 7

[0129] This comparative example provides a SnO2-based target material and a preparation method thereof. The difference between this comparative example and Example 1 lies only in the difference in the mass fractions of some of the preparation raw material components: 93 parts of tin oxide, 3 parts of tantalum oxide, 3 parts of zinc oxide, and 1 part of gadolinium oxide. No tungsten oxide is added. The remaining raw material components and preparation method are consistent with Example 1.

[0130] Comparative Example 8

[0131] This comparative example provides a SnO2-based target material and a preparation method thereof. The difference between this comparative example and Example 1 lies only in the difference in the mass fractions of some of the preparation raw material components: 90.5 parts of tin oxide, 3.5 parts of tantalum oxide, 3.5 parts of zinc oxide, 1.5 parts of tungsten oxide, and 1 part of gadolinium oxide. The remaining raw material components and preparation methods are consistent with Example 1.

[0132] In this comparative example, the target material cracked during the hot pressing sintering process, and therefore could not meet the application requirements.

[0133] Comparative Example 9

[0134] This comparative example provides a SnO2-based target material and a preparation method thereof. The difference between this comparative example and Example 1 lies only in the difference in the mass fractions of some of the preparation raw material components: 89.5 parts of tin oxide, 3 parts of tantalum oxide, 3 parts of zinc oxide, 1.5 parts of tungsten oxide, and 2 parts of gadolinium oxide. The remaining raw material components and preparation methods are consistent with those of Example 1.

[0135] In this comparative example, the target material cracked during the hot pressing sintering process, and therefore could not meet the application requirements.

[0136] Test Case

[0137] The tin oxide-based targets prepared in each embodiment and comparative example were tested. The density of the final target was tested using the Archimedes drainage method, and the resistivity of the target was tested using a resistivity meter.

[0138] The test results and the oxide raw material component parts of each embodiment and comparative example are shown in Table 1:

[0139] Table 1 Oxide raw material component parts and density and resistivity test results of each embodiment and comparative example

[0140] From the above test results, it can be seen that in Comparative Example 1, since only tin oxide is used without doping with other oxide components, the density of the SnO2-based target prepared by sintering is relatively low, only 6.04 g / m 3 , and its resistivity is very high, reaching 2.47×10 7 Ω·cm, so it has almost no conductive performance; Comparative Example 2 greatly improves the sintering density of the SnO2-based target by doping with tantalum oxide, and causes the resistivity of the target to decrease, but the resistivity is still relatively high; Comparative Example 3 can also improve the sintering density of the SnO2-based target by doping with zinc oxide, and significantly reduce the resistivity of the target, but it is still difficult to meet the requirements of DC power supply magnetron sputtering coating; Comparative Example 4 achieves a significant increase in target density by doping tantalum oxide and zinc oxide at the same time, reaching 6.62g / m 3 , and its resistivity is further reduced compared with Comparative Example 3, but it still does not reach the ideal value; Comparative Example 5, based on Comparative Example 4, further doped with tungsten oxide, achieved the technical effect of slightly improving the target density and further reducing the resistivity, but its resistivity still has room for improvement; Comparative Example 6, based on Comparative Example 1, simultaneously doped with tungsten oxide and gadolinium oxide, achieved the technical effect of significantly reducing the resistivity of the SnO2-based target, but its sintering density is too low, and the density of the prepared target is low, so its resistivity still cannot reach the ideal resistance value; Comparative Example 7, based on Comparative Example 4, further doped with gadolinium oxide, achieved the technical effect of slightly improving the target density and further reducing the resistivity, but its resistivity still has room for improvement; Comparative Example 8 simultaneously doped with four oxides, but due to the excessive doping amounts of tantalum oxide and zinc oxide, the tin oxide lattice distortion is large, and the target cracks during sintering; similarly, due to the excessive doping amount of gadolinium oxide in Comparative Example 9, the tin oxide lattice distortion is large, and the target cracks during sintering, and all of them cannot be used.

[0141] Examples 1 to 9 achieve the technical effect of preparing high-density and ultra-low-resistivity SnO2-based targets by rationally configuring the four oxides and controlling their appropriate doping amounts. The rational doping of tantalum oxide and zinc oxide increases the target's density and reduces its resistivity. Furthermore, the rational addition of tungsten oxide and gadolinium oxide significantly reduces the target's resistivity, ultimately yielding a sintered body with excellent density and a resistivity further reduced compared to the comparative example. The prepared targets exhibit excellent resistivity and density, and the processed targets are stable for DC magnetron sputtering coating.

[0142] In summary, in the present application, the rational doping of tantalum oxide, zinc oxide, tungsten oxide and gadolinium oxide in tin oxide-based target material achieves the technical effect of improving target density and fully reducing resistivity, and explores the optimal addition amount of each doped oxide. Among them, when tantalum oxide is doped, since the radius of Ta element is 0.064nm, which is smaller than that of Sn element, Ta element can replace the position of Sn element to form Sn (1-x) Ta x O2 solid solution, and because the valence state of Ta element is 5+, which is higher than the valence state of Sn element 4+, the substitution of Ta element will introduce electron holes in SnO2, increase the carrier concentration, and thus improve the conductive properties of SnO2; in addition, the substitution of Ta element will also affect the crystal structure of SnO2, causing its lattice constant to change. As the doping amount of Ta element increases, the substitution of Ta element will make the crystal structure of SnO2 more compact and stable; the substitution of Ta element will also affect the sintering behavior and density of SnO2. As the doping amount of Ta element increases, the sintering temperature of SnO2 will decrease, and the density after sintering will also increase. This is because the substitution of Ta element will promote the grain growth and grain boundary diffusion of SnO2, thereby accelerating the sintering process and reducing porosity. When zinc oxide is doped, due to Zn 2+ The radius of 0.074nm is larger than Sn 4+ The radius of the target is 0.071nm. When Zn replaces Sn, the adjacent oxygen atoms will be separated to form oxygen vacancies, which promotes the development of the SnO2 lattice and generates a large number of electrons, greatly increasing the conductivity. At the same time, within a certain doping range, ZnO reacts with SnO2 at high temperature to form Zn2SnO4, filling the gaps between the particles, greatly enhancing the sintering and densification of the target, and achieving sintering assistance for tin oxide-based targets and promoting sintering and densification. However, excessive ZnO doping will cause the target to sinter and crack, and delaminate. When tungsten oxide is doped, since W is an important cationic dopant in tin oxide-based transparent conductive materials, W is added to the target. 6+ Replace Sn 4+ , can enhance the electronic and optical properties of tin oxide; in addition, W 6+It has the highest valence state among common doping elements and can generate more free electrons. At the same time, the doping of W element also helps to generate more carriers and maintain the structural capacity of tin oxide. When gadolinium oxide is doped, the 4f electrons of Gd ions will form hybrid orbitals with SnO2, thereby increasing the carrier concentration and enabling more electrons to jump to the conduction band. At the same time, the band structure of doped SnO2 is more compatible with the perovskite layer of solar cells than pure SnO2, which may lead to higher charge transfer between the electron transport layer and the perovskite interface and less interface recombination. In addition, as a rare earth element, Gd also has strong light absorption, which will change the optical properties of SnO2 and affect its application in optoelectronic devices. Although Gd doping can improve the conductivity of SnO2, too high doping concentration may cause lattice distortion, affecting the stability and other physical properties of SnO2. Therefore, choosing the appropriate doping concentration is very important.

[0143] In addition, compared with the existing ITO target materials used for heterojunction and perovskite solar cells, the main material of this application scheme is tin oxide, which is cheaper and more environmentally friendly. The density of the target material is improved by doping Ta and Zn elements, and the density of the prepared target material reaches 6.61g / m 3 -6.72g / m 3 At the same time, by doping W and Gd elements to reduce the resistivity of the target material and adjusting the photoelectric properties of tin oxide, the resistivity of the prepared target material was reduced to 1.07×10 -3 Ω·cm-1.74×10 -3 Ω·cm, the tin oxide-based target prepared in the present application is suitable for DC power supply magnetron sputtering coating, and can also be used in photovoltaic heterojunction cells and perovskite cells, because it has good light transmittance and low resistivity, which can improve the battery conversion efficiency.

[0144] The embodiments of the present application have been described in detail above, but the present application is not limited to the above embodiments. Various modifications can be made within the scope of knowledge possessed by a person skilled in the art without departing from the scope of protection of the present application. In addition, the embodiments of the present application and the features of the embodiments can be combined with each other unless there is a conflict.

Claims

1. A tin oxide-based target, characterized in that, The preparation raw materials by mass parts include: 91 - 95 parts of tin oxide, 1.5 - 3.5 parts of tantalum oxide, 1.5 - 3.5 parts of zinc oxide, 0.5 - 2 parts of tungsten oxide, 0.3 - 1.5 parts of gadolinium oxide.

2. The tin oxide-based target according to claim 1, characterized in that, The preparation raw materials further include a binder and a plasticizer; Preferably, by mass parts, the binder is 0.4 - 2.5 parts, and the plasticizer is 0.1 - 2 parts.

3. The tin oxide-based target according to claim 2, characterized in that, The preparation raw materials by mass parts include: 91.5 - 94.5 parts of tin oxide, 2 - 3 parts of tantalum oxide, 2 - 3 parts of zinc oxide, 1 - 1.5 parts of tungsten oxide, 0.5 - 1 part of gadolinium oxide, 0.5 - 2 parts of binder, 0.5 - 1.5 parts of plasticizer.

4. The tin oxide-based target according to claim 3, wherein The density of the tin oxide-based target is ≥ 6.5 g / m 3 .

5. The tin oxide-based target according to claim 3, wherein The resistivity of the tin oxide-based target is ≤ 1×10 -2 Ω·cm.

6. A method for preparing an indium tin oxide target according to any one of claims 1 to 5, characterized in that, It includes the following steps: S1: Mix the oxide preparation raw materials, ball mill, and spray dry; S2: Obtain a green body by isostatic pressing; S3: Debind, hot press sinter, and then obtain the tin oxide - based target.

7. The preparation method according to claim 6, characterized in that, The pressure of the isostatic pressing in step S2 is 100 MPa - 200 MPa.

8. The preparation method according to claim 6, characterized in that, The temperature of the debinding in step S3 is 600 °C - 650 °C, and the time is 2 h - 3 h.

9. The preparation method according to claim 6, characterized in that, The hot press sintering in step S3 includes the following steps: S31: Keep warm at 600 °C - 650 °C for 5 h - 7 h; S32: Keep warm at 950 °C - 1000 °C for 3 h - 4 h; S33: Keep warm and hold pressure at 1350 °C - 1400 °C and a pressure of 25 MPa - 35 MPa for 2 h - 3 h.

10. The application of the tin oxide - based target according to any one of claims 1 to 5 in coating, battery, transistor, and display panel.

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