A multi-component doped indium oxide target, its preparation method and application

Abstract

This invention belongs to the field of oxide target technology, specifically disclosing a multi-element doped indium oxide (IGTO) target, its preparation method, and its applications. The raw material components of the multi-element doped IGTO target of this invention include indium oxide, gallium oxide, titanium dioxide, and zirconium oxide. The zirconium-doped IGTO target of this invention has a lower sintering temperature, higher density, and lower resistivity, enabling the preparation of high-performance IGTO thin films with high transmittance and low subthreshold swing, thus improving the stability of thin-film devices and showing great promise for applications in perovskite solar cells. This invention also provides a preparation method and applications for the multi-element doped IGTO target.

Description

Technical Field

[0001] This invention relates to the field of oxide target technology, and in particular to a multi-doped indium oxide target, its preparation method, and its application. Background Technology

[0002] Heterojunction perovskite solar cells are among the fastest-growing next-generation solar cells in recent years. This is mainly due to advancements in more efficient device structures and manufacturing processes, leading to further improvements in the perovskite active layer and enhanced control over the interface layer. These advancements result in advantages such as high power conversion efficiency, long carrier lifetime, long exciton diffusion length, and low-temperature solution processing costs. Heterojunction perovskite solar cells are considered a crucial future direction for the photovoltaic industry. To ensure high performance, the design of the transparent cathode and anode materials is also critical.

[0003] Currently, typical anodes for perovskite solar cells, such as ITO (indium tin oxide) anodes, are deposited on rigid glass substrates using atmospheric pressure chemical vapor deposition at high substrate temperatures via direct current (DC) sputtering. These anodes typically exhibit high transmittance (over 80%) and low sheet resistance. However, these electrodes still face several challenges, including relatively low power conversion efficiency, low throughput, and poor chemical and environmental stability. Amorphous Ga and Ti co-doped indium oxide (IGTO) electrodes hold great potential as a viable alternative to ITO electrodes; however, current IGTO electrodes suffer from poor stability and are prone to issues such as discharge and nodulation, which can negatively impact motor performance.

[0004] Therefore, there is an urgent need to further improve the IGTO electrode used in perovskite solar cells to enhance its overall performance and production efficiency in order to meet the needs of the ever-evolving perovskite solar cell technology. Summary of the Invention

[0005] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a multi-element doped indium oxide target. The multi-element doped indium oxide target of this invention is a zirconium-doped indium gallium titanium oxide (IGTO) target. This IGTO target has a low sintering temperature, high density, and low resistivity, which can be used to prepare high-performance IGTO thin films with high transmittance and low subthreshold swing (SS), thereby improving the stability of thin-film devices and showing great promise for application in perovskite solar cells.

[0006] The present invention also provides a method for preparing the above-mentioned indium oxide target.

[0007] The present invention also provides an indium oxide thin film.

[0008] The present invention also proposes applications of the above-mentioned indium oxide target and thin film.

[0009] In a first aspect, the present invention provides an indium oxide target material, wherein the raw material components of the indium oxide target material include indium oxide, gallium oxide, titanium dioxide and zirconium oxide.

[0010] According to specific embodiments of the present invention, the indium oxide target provided by the present invention has at least the following beneficial effects: by doping gallium oxide and titanium dioxide into an indium oxide-based target, an IGTO target is obtained. In order to improve the overall performance of the target and the prepared thin film, the present invention further dops zirconium into the IGTO target, thereby reducing the sintering temperature of the IGTO target, increasing the density of the target and reducing the resistivity, and preparing an IGTO thin film with excellent performance. The prepared thin film has high transmittance and low subthreshold swing (SS), thereby improving the stability of the thin film device and the performance of the prepared IGTO electrode.

[0011] According to some embodiments of the present invention, the raw material components, by mass parts, include 88-96 parts of indium oxide, 0.5-2 parts of gallium oxide, 1-3 parts of titanium dioxide, and 0.5-8 parts of zirconium oxide.

[0012] According to some embodiments of the present invention, the raw material components, by mass parts, include 92-96 parts of indium oxide, 1-2 parts of gallium oxide, 1-2.5 parts of titanium dioxide, and 1-4 parts of zirconium oxide.

[0013] According to some embodiments of the present invention, the raw material components, by mass parts, include 92-96 parts of indium oxide, 1-2 parts of gallium oxide, 1-2.5 parts of titanium dioxide, and 1.5-3 parts of zirconium oxide.

[0014] This invention further explores the amount of zirconium doping in IGTO targets. After testing various properties of the target and the film, the optimal zirconium doping ratio was obtained, which makes the IGTO target have extremely high density and low resistivity, while the IGTO film prepared by it also has high transmittance and low subthreshold swing (SS), thereby improving the production performance and overall performance phenotype of IGTO electrodes.

[0015] According to some embodiments of the present invention, the raw material components include indium oxide powder, gallium oxide powder, titanium dioxide powder, and zirconium oxide powder.

[0016] A second aspect of the present invention provides a method for preparing an indium oxide target as described in the first aspect of the present invention, comprising the following steps:

[0017] S1. The raw material components are mixed and ground, and a dispersant, water and binder are added during the grinding process to obtain a mixed slurry;

[0018] S2. Spray granulation is performed on the mixed slurry to obtain mixed powder, the mixed powder is pressed into shape, and then cold isostatic pressing is performed to obtain a green body.

[0019] S3. Sinter the green blank to obtain the indium oxide target.

[0020] The maximum sintering temperature in step S3 is 1200~1300℃.

[0021] According to specific embodiments of the present invention, the preparation method of indium oxide target provided by the present invention is mature and can be used for large-scale industrial production. This preparation method can prepare the indium oxide target described in the first aspect of the present invention, and therefore also includes the aforementioned advantages of the indium oxide target of the present invention. Furthermore, the present invention has conducted extensive experimental exploration on the preparation method of the indium oxide target, discovering that the maximum sintering temperature of the target can be reduced, thereby reducing production costs. It has also been found that the maximum sintering temperature in the target sintering process is related to the achievement of the technical effect of zirconium doping. The present invention has explored suitable target sintering processes, achieving the best comprehensive performance of the zirconium-doped IGTO target and IGTO thin film.

[0022] According to some embodiments of the present invention, the grinding in step S1 is ball milling, which is divided into three ball millings in sequence. The first ball milling mixes the raw material components, the second ball milling adds the dispersant and water, and the third ball milling adds the binder.

[0023] Since the proportion of doped powder is relatively small, the first ball milling in this invention is a pre-mixing of powder to facilitate more uniform mixing in the subsequent process. The second and third ball millings, in which the dispersant and binder are added separately, are also mainly to make the powder ball milling more uniform, which is beneficial for subsequent sintering.

[0024] According to some embodiments of the present invention, the dispersant comprises polyvinylpyrrolidone or an amine salt of an acrylic copolymer.

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

[0026] According to some embodiments of the present invention, the sintering in step S3 is divided into: First, placing the green blank in a sintering furnace and heating it from room temperature to 500-600°C at a heating rate of 2-4°C / min, holding it at that temperature for 1-3 hours; Second, heating it to 900-1100°C at a heating rate of 0.5-2°C / min, holding it at that temperature for 3-5 hours; Third, introducing oxygen into the sintering furnace and heating it to 1... The first step is to heat the material at 150~1200℃ for 4~6 hours; the second step is to heat it at a rate of 0.3~1℃ / min to the highest sintering temperature of 1200~1300℃ and hold it for 1~3 hours; the third step is to stop the oxygen supply after the holding period, cool it down to 900~1100℃ at a rate of 0.5~2℃ / min and hold it for 1~3 hours, and then cool it down to room temperature at a rate of 0.5~2℃ / min to obtain the multi-component doped indium oxide target.

[0027] In a third aspect, the present invention provides an indium oxide thin film, wherein the raw materials for preparing the indium oxide thin film include the indium oxide target material described in the first aspect of the present invention.

[0028] According to some embodiments of the present invention, the subthreshold swing of the indium oxide thin film is less than 1V / dec.

[0029] According to some embodiments of the present invention, the subthreshold swing of the indium oxide thin film is less than 0.8V / dec.

[0030] In a fourth aspect, the invention proposes the application of the indium oxide target as described in the first aspect or the indium oxide thin film as described in the third aspect in the fabrication of perovskite solar cells.

[0031] According to some embodiments of the present invention, the application is to prepare the anode electrode of a perovskite solar cell.

[0032] 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

[0033] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0034] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0035] Example 1

[0036] This embodiment provides a multi-doped indium oxide target and its preparation method.

[0037] The raw material composition of the multi-doped indium oxide target in this embodiment, by mass parts, is: 94.97 parts indium oxide (In2O3), 1.34 parts gallium oxide (Ga2O3), 1.69 parts titanium dioxide (TiO2), and 2 parts zirconium oxide (ZrO2).

[0038] The preparation steps of the multi-doped indium oxide target in this embodiment are as follows:

[0039] 1) According to the above-mentioned mass proportions, indium oxide powder, gallium oxide powder, titanium dioxide powder, and zirconium oxide powder are mixed and ball-milled for 1 hour to ensure uniform mixing of the oxide powders; then deionized water and 3 parts of polyvinylpyrrolidone dispersant are added to obtain a mixed slurry, which is then ball-milled for 40 hours; finally, 3.385 parts of polyvinyl alcohol binder are added and ball-milled for 1 hour.

[0040] The zirconium beads used in the ball mill are 0.3mm in size, and the ball-to-material ratio is 1.2:1.

[0041] 2) Spray dry the ball-milled slurry and granulate it to obtain a mixed powder;

[0042] 3) The mixed powder is injected into the mold for molding, and then subjected to cold isostatic pressing at a pressure of 220MPa and a holding time of 5min to obtain the target blank;

[0043] 4) The target blank is sintered and cooled to obtain the target material. The sintering process is as follows: First, the target blank is placed in a sintering furnace and heated from room temperature to 550℃ at a heating rate of 3℃ / min, and held for 2 hours. Second, the temperature is increased to 1000℃ at a heating rate of 1℃ / min and held for 4 hours. Third, oxygen is introduced into the sintering furnace and the temperature is increased to 1180℃ at a heating rate of 0.5℃ / min, and held for 5 hours. Fourth, the temperature is increased to the maximum sintering temperature of 1250℃ at a heating rate of 0.5℃ / min and held for 2 hours. Fifth, after the holding period, the oxygen supply is stopped, the temperature is decreased to 1000℃ at a cooling rate of 1℃ / min, held for 2 hours, and then decreased to room temperature at a cooling rate of 1℃ / min to obtain the multi-element doped indium oxide target material.

[0044] In this embodiment, the sintered target material is further processed and polished according to the size requirements to obtain the finished target material.

[0045] Examples 2 to 6

[0046] Examples 2-6 provide a series of multi-component doped indium oxide targets, which differ from Example 1 only in the amount of raw materials used. The amounts of raw material components are shown in Table 1, and the preparation method is the same as that of Example 1.

[0047] Comparative Examples 1 to 3

[0048] Comparative Examples 1-3 provide a series of multi-component doped indium oxide targets, which differ from Example 1 in the amount of raw materials used or the maximum sintering temperature. The amount of raw material components and the maximum sintering temperature are shown in Table 1.

[0049] Table 1. Target material composition and maximum sintering temperature for each embodiment and comparative example.

[0050]

[0051] Sputtering coating:

[0052] IGTO thin films were prepared by magnetron sputtering using the targets prepared in Examples 1-6 and Comparative Examples 1-3, respectively. The thickness of the oxide thin film was 100 nm, and the substrate was a 10*10 mm plastic substrate.

[0053] Performance testing:

[0054] The density of the targets prepared in each embodiment and comparative example was determined using the Archimedes displacement method, with the relative density being the ratio of the actual density to the theoretical density measured by the displacement method. The resistivity of the targets prepared in each embodiment and comparative example was measured using a four-probe resistivity meter. The transmittance of the IGTO films prepared from the targets in each embodiment and comparative example was measured using a dual-beam UV-Vis spectrophotometer. The subthreshold swing (SS) of the IGTO films was measured using a Keythley 2636 semiconductor tester. The test results are shown in Table 2.

[0055] Table 2 Performance test results of the targets and prepared thin films in each embodiment and comparative example.

[0056]

[0057] The test results above show that the multi-doped indium oxide target prepared using the method of the present invention has a high relative density, reaching over 89%, and a low resistivity, which can reach below 0.4 mΩ·cm. Furthermore, sputtering coating using the target prepared using the method of the present invention can yield an IGTO thin film with high transmittance and low subthreshold swing (SS). The subthreshold swing can measure the trap state density of the device, and the smaller the SS value, the higher the stability of the thin film device.

[0058] Comparing Examples 1-6 with Comparative Example 1, it can be seen that doping the IGTO target with zirconium can reduce the subthreshold swing (SS) of the IGTO thin film prepared from the target. Furthermore, as the zirconium doping concentration increases, the subthreshold swing (SS) of the IGTO thin film gradually decreases, resulting in better stability of the thin-film device. Analysis suggests that adding zirconium doping to indium oxide, which is already doped with gallium and titanium, suppresses oxygen vacancies in the thin film due to the high binding energy between zirconium and oxygen atoms. This reduces the number of oxygen vacancies in the bulk, further improving the device stability.

[0059] Comparing Example 1 and Comparative Examples 1-3, it can be seen that zirconium doping also helps to reduce the maximum sintering temperature of the IGTO target. However, excessively high maximum sintering temperatures, such as 1430°C in Comparative Example 3, actually affect the effect of zirconium doping and make it difficult to effectively reduce the subthreshold swing (SS) of the IGTO thin film. Furthermore, compared to Comparative Example 2 which is not doped with zirconium, Comparative Example 3, which uses the original maximum sintering temperature of 1430°C, also leads to a decrease in the relative density of the target and an increase in resistivity, as well as a decrease in the light transmittance of the prepared thin film, making it difficult to prepare IGTO thin film devices with excellent performance.

[0060] Zirconium doping also acts as a sintering aid, facilitating the formation of liquid-phase sintering of the target material. Since the mass transfer rate in liquid-phase sintering is faster than that in diffusion, the densification rate is high, allowing for the production of a denser sintered body at a lower temperature than solid-state sintering. However, the test results in Examples 2 and 3 also show that excessive zirconium doping actually reduces the relative density of the target material. This is attributed to the fact that excessive zirconium doping affects the formation and distribution of the liquid phase, thus impacting mass migration and densification rates during sintering. It may also lead to uneven liquid phase distribution, preventing uniform mixing and sintering, and consequently affecting the relative density and uniformity of the sintered body.

[0061] The embodiments of the present invention have been described in detail above. 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. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. An indium oxide target, characterized in that, The raw material components of the indium oxide target include indium oxide, gallium oxide, titanium dioxide and zirconium oxide. The preparation method of the indium oxide target includes sintering the formed blank to obtain the indium oxide target. The maximum sintering temperature is 1200~1300℃.

2. The indium oxide target according to claim 1, characterized in that, The raw material components, by mass, include 88-96 parts indium oxide, 0.5-2 parts gallium oxide, 1-3 parts titanium dioxide, and 0.5-8 parts zirconium oxide.

3. The indium oxide target according to claim 2, characterized in that, The raw material components, by mass, include 92-96 parts indium oxide, 1-2 parts gallium oxide, 1-2.5 parts titanium dioxide, and 1-4 parts zirconium oxide.

4. A method for preparing an indium oxide target as described in any one of claims 1 to 3, characterized in that, Includes the following steps: S1. The raw material components are mixed and ground, and a dispersant, water and binder are added during the grinding process to obtain a mixed slurry; S2. Spray granulation is performed on the mixed slurry to obtain mixed powder, the mixed powder is pressed into shape, and then cold isostatic pressing is performed to obtain a green body. S3. The green blank is sintered to obtain indium oxide target material.

5. The preparation method according to claim 4, characterized in that, The grinding in step S1 is ball milling, which is divided into three ball milling processes. The first ball milling mixes the raw material components, the second ball milling adds the dispersant and water, and the third ball milling adds the binder.

6. The preparation method according to claim 4, characterized in that, The dispersant includes polyvinylpyrrolidone or an amino salt of an acrylic copolymer; and / or, the binder includes polyvinyl alcohol or sodium polyacrylate.

7. The preparation method according to claim 4, characterized in that, The sintering process in step S3 consists of the following steps: First, the green blank is placed in a sintering furnace and heated from room temperature to 500-600°C at a heating rate of 2-4°C / min, and held at that temperature for 1-3 hours; Second, the temperature is increased to 900-1100°C at a heating rate of 0.5-2°C / min, and held at that temperature for 3-5 hours; Third, oxygen is introduced into the sintering furnace, and the temperature is increased to 1150-1200°C at a heating rate of 0.3-1°C / min. First, heat the material at 0℃ for 4-6 hours. Second, heat it at a rate of 0.3-1℃ / min to the maximum sintering temperature of 1200-1300℃ and hold it for 1-3 hours. Third, after holding the material at 0℃, stop the oxygen supply and cool it down to 900-1100℃ at a rate of 0.5-2℃ / min, hold it for 1-3 hours, and then cool it down to room temperature at a rate of 0.5-2℃ / min to obtain the multi-component doped indium oxide target.

8. An indium oxide thin film, characterized in that, The raw materials for preparing the indium oxide thin film include the indium oxide target material as described in any one of claims 1 to 3.

9. The indium oxide thin film according to claim 8, characterized in that, The subthreshold swing of the indium oxide thin film is less than 1V / dec.

10. The application of the indium oxide target as described in any one of claims 1 to 3 or the indium oxide thin film as described in any one of claims 8 to 9 in the fabrication of perovskite solar cells.

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