Preparation process of rotary indium-free target material for solar cell

Abstract

The invention discloses a preparation process of a rotary indium-free target material for a solar cell, and relates to the technical field of indium-free target materials, and the preparation process comprises the following steps: mixing gallium and zinc according to a mass ratio of (2-3): 7, heating to 400-600 DEG C in an inert atmosphere, and keeping the temperature until the gallium and the zinc are completely fused to obtain a gallium-zinc alloy liquid; titanium dioxide accounting for 0.5%-2% of the total mass of the gallium-zinc alloy liquid is added into the gallium-zinc alloy liquid, the mixture is evenly mixed and then cooled to the normal temperature, and a gallium-zinc alloy cast ingot is obtained; the gallium-zinc alloy cast ingot is subjected to annealing treatment; the annealed gallium-zinc alloy cast ingot is cut into target material sheets, and the surfaces of the target material sheets are polished; and carrying out heat treatment or coating treatment on the target material sheet. The electron mobility of the material is improved through the gallium-zinc alloy, so that the electric energy conversion efficiency of the solar cell is enhanced; and the indium-free material is used as the target material, so that the cost is reduced, and meanwhile, the solar cell has higher sustainability.

Description

Technical Field

[0001] The invention relates to the technical field of indium-free target materials, and in particular to a process for preparing a rotating indium-free target material for a solar cell. Background Art

[0002] In the process of developing new solar cell materials, the target material is an important factor affecting the performance of the cell. In recent years, the scarcity and price increase of indium have prompted researchers to look for indium-free alternative materials. At the same time, sputtering technology (especially rotary sputtering technology) has become one of the important methods of thin film deposition due to its high efficiency, precision and controllability. Therefore, a rotary indium-free target material suitable for solar cells is urgently needed. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a process for preparing a rotating indium-free target for solar cells, and the specific technical solution is as follows:

[0004] A process for preparing a rotating indium-free target for solar cells comprises the following steps:

[0005] Step 1: Gallium and zinc are mixed in a mass ratio of (2-3):7 and heated to 400-600° C. in an inert atmosphere, and the temperature is maintained until the gallium and zinc are completely fused to obtain a gallium-zinc alloy liquid;

[0006] Step 3: adding 0.5% to 2% of the total mass of titanium dioxide to the gallium-zinc alloy liquid, mixing evenly and cooling to room temperature to obtain a gallium-zinc alloy ingot;

[0007] Step 4: annealing the gallium-zinc alloy ingot, the annealing temperature is controlled at 200-300° C., and the annealing time is 2 to 4 hours;

[0008] Step 5: cutting the annealed gallium-zinc alloy ingot into target sheets, and polishing the surface of the target sheets;

[0009] Step 6: performing surface treatment on the target sheet, wherein the surface treatment step includes heat treatment or coating treatment.

[0010] Preferably, the inert atmosphere used in step 1 is argon, and its purity is not less than 99.99%. The heating under the inert atmosphere specifically includes: placing the gallium-zinc mixture in a heating furnace, ensuring that the argon flow rate is maintained at 0.5-1.0 L / min during the heating process, the heating process continues until the alloy is completely melted, and the alloy liquid maintains the temperature for 1-2 hours to ensure that the gallium and zinc are fully fused.

[0011] Preferably, step 4 specifically includes: maintaining uniform argon flow in the annealing furnace, with the flow rate set to 0.5-1.5 L / min, placing the target sheet in the middle of the annealing furnace during annealing to ensure uniform temperature distribution, and controlling the annealing temperature at 250° C. for 3 hours.

[0012] Preferably, the surface treatment step in step 6 is heat treatment, which specifically includes: placing the annealed gallium-zinc alloy target sheet in a heat treatment furnace, using argon protective atmosphere, maintaining the gas flow rate at 0.5-1.0 L / min, controlling the heat treatment temperature at 300°C, and lasting for 1-2 hours.

[0013] Preferably, aluminum is also mixed in the gallium-zinc alloy liquid, wherein the mass ratio of gallium, zinc and aluminum is (2-3):7:1.

[0014] Preferably, the cooling in step 3 specifically includes: after the gallium-zinc alloy liquid is evenly mixed, the alloy liquid is quickly poured into a cooling mold, the cooling mold is made of a high-temperature resistant alloy or a ceramic material, and during the cooling process, the alloy liquid is ensured to maintain uniform flow. The cooling method adopts water cooling, the water flow rate is set to 0.5-2.0L / min, the cooling water temperature is controlled at 15-25°C, and the water cooling process lasts for 30-60min.

[0015] Preferably, the surface treatment step in step 6 is a coating treatment, and the coating is a self-assembled monomolecular coating.

[0016] Preferably, the coating treatment specifically comprises the following steps:

[0017] Use isopropyl alcohol to clean the surface of the target sheet;

[0018] Soak the target sheet in dilute nitric acid solution for 10 to 15 minutes, rinse with deionized water and blow dry with nitrogen;

[0019] Place the target sheet in a UV-ozone treatment device for 10 to 30 minutes;

[0020] Adding octyl mercaptan to the solvent, stirring evenly, and then adding a surfactant to prepare an octyl mercaptan solution with a concentration of 0.1% to 1%;

[0021] The treated target sheet is immersed in octyl mercaptan solution, taken out after 1 to 2 hours, rinsed with deionized water, and dried with nitrogen.

[0022] Preferably, step 1 further includes the following steps:

[0023] Step 2: Add 0.5% to 2% of the total mass of nanoparticles into the gallium-zinc alloy liquid and mix them evenly.

[0024] Preferably, the nanoparticles are silicon nitride nanoparticles, and the preparation steps include:

[0025] After mixing silicon powder and urea in a molar ratio of 1:3, heat to 1200-1400°C in an argon protective atmosphere;

[0026] The product after the reaction was cooled to room temperature, ground using a ball mill, and sieved to obtain nanoparticles with a particle size of <100 nm;

[0027] The nanoparticles were washed with distilled water and then dried at 60° C. to obtain high-purity silicon nitride nanoparticles.

[0028] The target material prepared by the process for preparing a rotating indium-free target material for solar cells provided by the present invention has the following beneficial effects:

[0029] 1. Improve the electron mobility of the material by alloying gallium and zinc, thereby enhancing the energy conversion efficiency of solar cells.

[0030] 2. Adding a small amount of titanium dioxide to the gallium-zinc alloy can effectively improve the oxidation resistance of the target material, prevent impurities and metal loss during the oxidation process, extend the service life of the material and improve its stability in high temperature and humid environments.

[0031] 3. Using indium-free materials as target materials reduces costs and also makes the solar cell more sustainable.

[0032] 4. Through annealing and surface treatment, the lattice stress of the target material is released, which improves the fatigue resistance of the target material and reduces problems such as cracks and falling off that may occur during the production process, thereby improving the production quality of solar cells and the reliability of long-term operation. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is described in detail below. The description in this section is only exemplary and explanatory and should not have any limiting effect on the scope of protection of the present invention.

[0034] This embodiment provides a process for preparing a rotating indium-free target for a solar cell, comprising the following steps:

[0035] Step 1: Gallium and zinc are mixed in a mass ratio of (2-3):7, and heated to 400-600° C. in an inert atmosphere, and the temperature is maintained until the gallium and zinc are completely fused to obtain a gallium-zinc alloy liquid.

[0036] Step 3: Add 0.5% to 2% of the total mass of titanium dioxide into the gallium-zinc alloy liquid, mix well and cool to room temperature to obtain a gallium-zinc alloy ingot, wherein the titanium dioxide is used as an additive to improve the performance of the target material.

[0037] Step 4: Annealing the gallium-zinc alloy ingot, with the annealing temperature controlled at 200-300°C and the annealing time being 2 to 4 hours, which helps to remove the internal stress in the alloy, improve the uniformity and mechanical properties of the material, and promote the improvement of the crystal structure of the target material.

[0038] Step 5: Cut the annealed gallium-zinc alloy ingot into target sheets, and polish the surface of the target sheets.

[0039] Step 6: Surface treatment is performed on the target sheet, wherein the surface treatment step includes heat treatment or coating treatment, so as to better meet the requirements of solar cells.

[0040] The target material prepared by the rotating indium-free target material preparation process for solar cells provided in this embodiment has the following beneficial effects:

[0041] 1. Improve the electron mobility of the material by alloying gallium and zinc, thereby enhancing the energy conversion efficiency of solar cells.

[0042] 2. Adding a small amount of titanium dioxide to the gallium-zinc alloy can effectively improve the oxidation resistance of the target material, prevent impurities and metal loss during the oxidation process, extend the service life of the material and improve its stability in high temperature and humid environments.

[0043] 3. Using indium-free materials as target materials reduces costs and also makes the solar cell more sustainable.

[0044] 4. Through annealing and surface treatment, the lattice stress of the target material is released, which improves the fatigue resistance of the target material and reduces problems such as cracks and falling off that may occur during the production process, thereby improving the production quality of solar cells and the reliability of long-term operation.

[0045] Furthermore, the inert atmosphere used in step 1 is argon, and its purity is not less than 99.99%. The heating under the inert atmosphere specifically includes: placing the gallium-zinc mixture in a heating furnace, ensuring that the argon flow rate is maintained at 0.5-1.0 L / min during the heating process, and the heating process continues until the alloy is completely melted, and the alloy liquid maintains the temperature for 1-2 hours to ensure that the gallium and zinc are fully fused.

[0046] Furthermore, step 4 specifically includes: maintaining uniform argon flow in the annealing furnace, with the flow rate set to 0.5-1.5 L / min, placing the target sheet in the middle of the annealing furnace during the annealing process to ensure uniform temperature distribution, and controlling the annealing temperature at 250° C. for 3 hours.

[0047] Furthermore, the surface treatment step in step 6 is heat treatment, and the heat treatment specifically includes: placing the annealed gallium-zinc alloy target sheet in a heat treatment furnace, using argon protective atmosphere, maintaining the gas flow rate at 0.5-1.0 L / min, controlling the heat treatment temperature at 300°C, and lasting for 1-2 hours.

[0048] Furthermore, aluminum is mixed in the gallium-zinc alloy liquid, wherein the mass ratio of gallium, zinc and aluminum is (2-3):7:1.

[0049] Furthermore, the cooling described in step 3 specifically includes: after the gallium-zinc alloy liquid is evenly mixed, the alloy liquid is quickly poured into a cooling mold, the cooling mold is made of a high-temperature resistant alloy or a ceramic material, and during the cooling process, the alloy liquid is ensured to maintain uniform flow. The cooling method adopts water cooling, the water flow rate is set to 0.5-2.0L / min, the cooling water temperature is controlled at 15-25°C, and the water cooling process lasts for 30-60min.

[0050] Furthermore, the surface treatment step in step 6 is a coating treatment, and the coating is a self-assembled monomolecular coating, which can effectively improve the conductivity of the gallium-zinc alloy target and the stability during sputtering.

[0051] Furthermore, the coating treatment specifically includes the following steps:

[0052] Use isopropyl alcohol to clean the surface of the target sheet.

[0053] The target sheet was soaked in a dilute nitric acid solution for 10 to 15 minutes, then rinsed with deionized water and dried with nitrogen.

[0054] The target sheet is placed in a UV-ozone treatment device for treatment for 10 to 30 minutes.

[0055] Octyl mercaptan is added into a solvent, stirred evenly, and then a surfactant is added to prepare an octyl mercaptan solution with a concentration of 0.1% to 1%.

[0056] The treated target sheet is immersed in octyl mercaptan solution, taken out after 1 to 2 hours, rinsed with deionized water, and dried with nitrogen.

[0057] Furthermore, after step 1, the following steps are also included:

[0058] Step 2: Add 0.5% to 2% of the total mass of nanoparticles into the gallium-zinc alloy liquid and mix them evenly.

[0059] Furthermore, the nanoparticles are silicon nitride nanoparticles. The excellent mechanical properties and thermal stability of silicon nitride can provide better support during the sputtering process, promote the release of materials and improve the sputtering efficiency. The preparation steps include:

[0060] Silicon powder and urea were mixed in a molar ratio of 1:3 and heated to 1200-1400°C in an argon protective atmosphere.

[0061] The product after the reaction was cooled to room temperature, ground using a ball mill, and sieved to obtain nanoparticles with a particle size of <100 nm.

[0062] The nanoparticles were washed with distilled water and then dried at 60° C. to obtain high-purity silicon nitride nanoparticles.

[0063] Specific examples are provided below. The provided examples may enable those skilled in the art to more fully understand the present invention, but do not limit the present invention in any way.

[0064] Example 1: Indium-free target made of gallium-zinc alloy doped with titanium dioxide

[0065] Under an argon atmosphere, 200g of gallium and 700g of zinc were mixed, and the mixture was placed in a high-temperature furnace, set at 550°C, and maintained at this temperature for 2 hours, during which time regular inspections and stirring were performed to ensure uniformity. After ensuring that the alloy liquid was free of bubbles and impurities, 14g of titanium dioxide was added to the alloy liquid and stirred evenly. The heating equipment was turned off, and the alloy liquid was water-cooled to room temperature to form a solid ingot, and the cooling time was 1 hour.

[0066] The ingot is placed in an annealing furnace, the annealing temperature is set to 250°C, maintained at this temperature for 2 hours, and then slowly cooled to room temperature to ensure that the internal structure of the ingot is uniform. The annealed ingot is cut into target sheets using a special cutting device, and the surface of the target sheet is polished using a polishing machine to ensure a smooth surface without scratches and defects.

[0067] The target piece was heated to 300° C. in an argon atmosphere and maintained at that temperature for 2 hours.

[0068] Example 2: Indium-free target made of gallium-zinc-aluminum alloy doped with titanium dioxide

[0069] Under an argon atmosphere, 200g of gallium, 700g of zinc and 100g of aluminum were mixed, and the mixture was placed in a high-temperature furnace, set at 550°C, and maintained at this temperature for 2 hours, during which time regular inspections and stirring were performed to ensure uniformity. After ensuring that the alloy liquid was free of bubbles and impurities, 14g of titanium dioxide was added to the alloy liquid and stirred evenly. The heating equipment was turned off, and the alloy liquid was water-cooled to room temperature to form a solid ingot, and the cooling time was 1 hour.

[0070] The ingot is placed in an annealing furnace, the annealing temperature is set to 250°C, maintained at this temperature for 2 hours, and then slowly cooled to room temperature to ensure that the internal structure of the ingot is uniform. The annealed ingot is cut into target sheets using a special cutting device, and the surface of the target sheet is polished using a polishing machine to ensure a smooth surface without scratches and defects.

[0071] The target piece was heated to 300° C. in an argon atmosphere and maintained at that temperature for 2 hours.

[0072] Example 3: Indium-free target treated by self-assembled monolayer coating

[0073] Under an argon atmosphere, 200g of gallium and 700g of zinc were mixed, and the mixture was placed in a high-temperature furnace, set at 550°C, and maintained at this temperature for 2 hours, during which time regular inspections and stirring were performed to ensure uniformity. After ensuring that the alloy liquid was free of bubbles and impurities, 14g of titanium dioxide was added to the alloy liquid and stirred evenly. The heating equipment was turned off, and the alloy liquid was water-cooled to room temperature to form a solid ingot, and the cooling time was 1 hour.

[0074] The ingot is placed in an annealing furnace, the annealing temperature is set to 250°C, the temperature is maintained for 2 hours, and then the temperature is slowly cooled to room temperature to ensure that the internal structure of the ingot is uniform. The annealed ingot is cut into target sheets using a special cutting device, and the surface of the target sheet is polished using a polishing machine to ensure that the surface is smooth and free of scratches and defects. The surface of the polished target sheet is cleaned with isopropanol, then immersed in a dilute nitric acid solution. After 15 minutes, it is rinsed with deionized water, blown dry with nitrogen, and then placed in a UV-ozone treatment device for 30 minutes. The treated target sheet is then immersed in an octyl mercaptan solution, taken out after 2 hours, rinsed with deionized water, and blown dry with nitrogen.

[0075] Embodiment 4:

[0076] 14g of silicon powder and 90g of urea were mixed and heated to 1400°C in an argon protective atmosphere for reaction. The product after the reaction was cooled to room temperature, ground using a ball mill, and sieved to obtain silicon nitride nanoparticles with an average particle size of 90nm. After washing with distilled water, it was placed in a drying oven and dried at 60°C to obtain high-purity silicon nitride nanoparticles.

[0077] Under an argon atmosphere, 200 g of gallium and 700 g of zinc were mixed, and the mixture was placed in a high-temperature furnace, set at 550 ° C, and maintained at this temperature for 2 hours, during which time it was checked and stirred regularly to ensure uniformity. After ensuring that the alloy liquid was free of bubbles and impurities, 14 g of titanium dioxide and 14 g of the above-mentioned high-purity silicon nitride nanoparticles were added to the alloy liquid and stirred evenly. The heating equipment was turned off, and the alloy liquid was water-cooled to room temperature to form a solid ingot, and the cooling time was 1 hour.

[0078] The ingot is placed in an annealing furnace, the annealing temperature is set to 250°C, maintained at this temperature for 2 hours, and then slowly cooled to room temperature to ensure that the internal structure of the ingot is uniform. The annealed ingot is cut into target sheets using a special cutting device, and the surface of the target sheet is polished using a polishing machine to ensure a smooth surface without scratches and defects.

[0079] The target piece was heated to 300° C. in an argon atmosphere and maintained at that temperature for 2 hours.

[0080] Comparative example: Indium zinc target

[0081] Under an argon atmosphere, 200 g of indium and 700 g of zinc were mixed, and the mixture was placed in a high-temperature furnace, the temperature was set to 550°C, and the temperature was maintained for 2 hours. During this period, regular inspection and stirring were performed to ensure uniformity. After ensuring that the alloy liquid was free of bubbles and impurities, the heating equipment was turned off, and the alloy liquid was water-cooled to room temperature to form a solid ingot. The cooling time was 1 hour.

[0082] The ingot is placed in an annealing furnace, the annealing temperature is set to 250°C, maintained at this temperature for 2 hours, and then slowly cooled to room temperature to ensure that the internal structure of the ingot is uniform. The annealed ingot is cut into target sheets using a special cutting device, and the surface of the target sheet is polished using a polishing machine to ensure a smooth surface without scratches and defects.

[0083] The target piece was heated to 300° C. in an argon atmosphere and maintained at that temperature for 2 hours.

[0084] The following are the test data of the targets prepared in Examples 1 to 4 and the comparative examples. The main indicators of the tests include:

[0085] Target thickness uniformity: Use a high-precision microscope to measure the thickness of the target sheet and select multiple different locations for measurement.

[0086] Surface roughness: Atomic force microscopy (AFM) was used to measure the roughness of the target surface.

[0087] Electrical properties: The resistivity of the target material was measured using the four-probe method.

[0088] Crystal structure: X-ray diffraction (XRD) equipment is used to analyze the crystal structure of the target material.

[0089] Optical properties: Use a spectrometer to measure the transmittance and reflectance of the target.

[0090] The test results are shown in the following table:

[0091]

[0092]

[0093] According to the test data, the target material thickness uniformity of Example 1 is better than that of the comparative example, indicating that the preparation process of the indium-free target material is relatively stable and can provide more consistent quality control; the surface roughness of Example 1 is superior to that of the comparative example in surface flatness, which helps to improve the photoelectric conversion efficiency of solar cells; the resistivity of Example 1 is better than that of the comparative example, which means that the electrical properties of the indium-free target material are better and can effectively improve the conductivity and overall efficiency of the battery. The main peaks of Example 1 appear at 28.4° (Zn) and 42.7° (Ga), indicating that the crystal structure of the target material is good, which is beneficial to the stability and electrical performance of the target material; the transmittance of Example 1 is 89.5%, which is higher than that of the comparative example, and the reflectivity is lower, indicating that the indium-free target material has certain advantages in optical properties and can be better used in high-efficiency solar cells.

[0094] The gallium-zinc alloy target used in Example 1 shows superiority over the indium target, especially in terms of electrical properties, surface flatness and optical properties. In addition, Examples 3 and 4 further improve the surface properties and stability of the target, and are expected to provide longer service life and higher solar cell conversion efficiency in practical applications.

[0095] The principles and implementation methods of the present invention are described herein using specific examples, and the description of the above embodiments is only used to help understand the method and core ideas of the present invention. The above are only preferred implementations of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention, which should be within the protection scope of the present invention.

Claims

1. A process for preparing a rotating indium-free target for solar cells, characterized in that: The steps include: S1: mixing gallium and zinc in a mass ratio of (2-3):7 and heating to 400-600° C. in an inert atmosphere, and maintaining the temperature until the gallium and zinc are completely fused to obtain a gallium-zinc alloy liquid; S3: adding 0.5% to 2% of the total mass of titanium dioxide to the gallium-zinc alloy liquid, mixing evenly and cooling to room temperature to obtain a gallium-zinc alloy ingot; S4: annealing the gallium-zinc alloy ingot, with the annealing temperature controlled at 200 to 300° C. and the annealing time being 2 to 4 hours; S5: cutting the annealed gallium-zinc alloy ingot into target sheets, and polishing the surface of the target sheets; S6: performing surface treatment on the target sheet, wherein the surface treatment step includes heat treatment or coating treatment.

2. The preparation process according to claim 1, characterized in that: The inert atmosphere used in step S1 is argon gas, and its purity is not less than 99.99%. The heating under the inert atmosphere specifically includes: placing the gallium-zinc mixture in a heating furnace, ensuring that the argon flow rate is maintained at 0.5-1.0 L / min during the heating process, and the heating process continues until the alloy is completely melted. The alloy liquid maintains the temperature for 1-2 hours to ensure that the gallium and zinc are fully fused.

3. The preparation process according to claim 1, characterized in that: Step S4 specifically includes: maintaining uniform argon flow in the annealing furnace, with the flow rate set to 0.5-1.5 L / min. During the annealing process, the target sheet is placed in the middle of the annealing furnace to ensure uniform temperature distribution. The annealing temperature is controlled at 250° C. and maintained for 3 hours.

4. The preparation process according to claim 1, characterized in that: The surface treatment step in step S6 is heat treatment, which specifically includes: placing the annealed gallium-zinc alloy target sheet in a heat treatment furnace, using argon protective atmosphere, maintaining the gas flow rate at 0.5-1.0 L / min, controlling the heat treatment temperature at 300°C, and lasting for 1-2 hours.

5. The preparation process according to claim 1, characterized in that: Aluminum is also mixed in the gallium-zinc alloy liquid, wherein the mass ratio of gallium, zinc and aluminum is (2-3):7:

1.

6. The preparation process according to claim 1, characterized in that: The cooling in step S3 specifically includes: after the gallium-zinc alloy liquid is evenly mixed, the alloy liquid is quickly poured into a cooling mold, the cooling mold is made of a high-temperature resistant alloy or a ceramic material, and during the cooling process, the alloy liquid is ensured to maintain a uniform flow. The cooling method adopts water cooling, the water flow rate is set to 0.5-2.0L / min, the cooling water temperature is controlled at 15-25°C, and the water cooling process lasts for 30-60min.

7. The preparation process according to claim 1, characterized in that: The surface treatment step in step S6 is coating treatment, and the coating is a self-assembled monomolecular coating.

8. The preparation process according to claim 7, characterized in that: The coating treatment specifically comprises the following steps: Use isopropyl alcohol to clean the surface of the target sheet; Soak the target sheet in dilute nitric acid solution for 10 to 15 minutes, rinse with deionized water and blow dry with nitrogen; Place the target sheet in a UV-ozone treatment device for 10 to 30 minutes; Adding octyl mercaptan to the solvent, stirring evenly, and then adding a surfactant to prepare an octyl mercaptan solution with a concentration of 0.1% to 1%; The treated target sheet is immersed in octyl mercaptan solution, taken out after 1 to 2 hours, rinsed with deionized water, and dried with nitrogen.

9. The preparation process according to claim 1, characterized in that: After step S1, the following steps are also included: S2: Add 0.5% to 2% of the total mass of nanoparticles into the gallium-zinc alloy liquid and mix them evenly.

10. The preparation process according to claim 9, characterized in that: The nanoparticles are silicon nitride nanoparticles, and the preparation steps include: After mixing silicon powder and urea in a molar ratio of 1:3, heat to 1200-1400°C in an argon protective atmosphere; The product after the reaction was cooled to room temperature, ground using a ball mill, and sieved to obtain nanoparticles with a particle size of <100 nm; The nanoparticles were washed with distilled water and then dried at 60° C. to obtain high-purity silicon nitride nanoparticles.

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