Method for preparing multi-metal ion doped nickel oxide nanoparticles

Abstract

The invention provides a method for preparing multi-metal ion doped nickel oxide nanoparticles, and belongs to the technical field of hole transport layer materials of perovskite solar cells. The preparation method comprises the following steps: directly reacting metal nickel with two or more of copper, indium, iron, cobalt, zinc and aluminum and acid, doping nickel hydroxide powder in a coprecipitation manner, and calcining at 270-350 DEG C for 2-4 hours to obtain metal ion doped nickel oxide nanoparticles. The method simplifies the synthesis steps of the raw materials and reduces the cost of the raw materials; through in-situ doping of the metal, uniform doping can be realized, growth of nano particles can be inhibited, smaller nano nickel oxide particles can be obtained, and meanwhile, the doped metal has the effect of improving the hole mobility. In addition, the method further has the advantage of being capable of being amplified, and mass production can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of hole transport layer materials for perovskite solar cells. Background Art

[0002] Nickel oxide (NiO) is an important functional material widely used in the optoelectronic field, especially as a hole transport layer material in perovskite solar cells. Traditionally, nickel oxide nanoparticles are prepared using nickel nitrate hexahydrate as a raw material (Advanced Materials 27.18 (2015): 2930-2937). However, this raw material is expensive, and the nano-nickel oxide particles prepared using this raw material exceed 10 nm in size (CN114763270B). In addition, although single element doping of nickel oxide nanoparticles can improve their performance ( Optics Express 24.22 (2016): A1349-A1359), but there is still room for improvement in hole mobility. Summary of the Invention

[0003] To address the aforementioned issues with existing technologies, reduce preparation costs, simplify production processes, and improve product performance, the development of a new preparation method has become an urgent need in this field. The present invention provides a method for preparing multi-metal ion-doped nickel oxide nanoparticles. This method significantly improves the preparation efficiency and hole mobility of nickel oxide nanoparticles by combining a one-step low-temperature dissolution process with a high-temperature calcination process. The technical solutions employed are as follows: A method for preparing metal ion-doped nickel oxide nanoparticles comprises the following steps: (1) mixing metallic nickel powder with two or more doping metal powders, and then directly dissolving the mixture in nitric acid to form a uniform mixed solution; the doping metal is selected from copper (Cu), indium (In), iron (Fe), cobalt (Co), zinc (Zn), zinc (Zn) and aluminum (Al); the molar ratio of the total amount of the doping metal to the metallic nickel is 1:100 to 1:5; (2) The mixed solution is naturally cooled to room temperature, and then a precipitant is gradually added under strong stirring to adjust the pH value to 9-11 to generate a doped nickel hydroxide precipitate; the precipitant is a sodium hydroxide aqueous solution or ammonia water; (3) separating the generated precipitate by centrifugation, washing with deionized water, and drying to obtain doped nickel hydroxide powder; (4) The dried powder is calcined at 270°C to 350°C for 2 to 4 hours to obtain metal ion-doped nickel oxide nanoparticles.

[0004] Preferably, in step (1), the mass percentage concentration of nitric acid is 8% to 21%, and the dissolution temperature is controlled at 40°C to 60°C.

[0005] Preferably, in step (2), the concentration of the precipitant is 7-13M.

[0006] Preferably, in step (3), the drying method is vacuum drying or freeze drying, and the drying time is 6 to 30 hours.

[0007] Beneficial effects of the present invention: The present invention provides a simple method for preparing multi-metal ion-doped nickel oxide nanoparticles, which has the characteristics of low cost, scalability, small size and high performance: the direct reaction of metal and acid simplifies the synthesis steps of raw materials and reduces the cost of raw materials; Example 2 successfully implements a 10-fold synthesis process, which has the advantage of scalability; through in-situ doping of metals, uniform doping can be achieved and the growth of nanoparticles can be suppressed, thereby obtaining smaller nano-nickel oxide particles. At the same time, the doped metal has the effect of improving hole mobility. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 : Particle size distribution of NiO synthesized in Example 1 and Comparative Example 1 tested by DLS; Figure 2 : Photo of the NiO product synthesized in Example 2. DETAILED DESCRIPTION

[0009] The technical solution of the present invention is further explained and illustrated in the following in the form of specific embodiments.

[0010] Example 1: Preparation of Cu-In dual-element doped nickel oxide nanoparticles (1) Mix 5 g of nickel powder, 0.2 g of copper powder and 0.1 g of indium powder, and dissolve them directly in 150 ml of 15% concentrated nitric acid. The dissolution temperature is controlled at 40 °C and stirred for 1 hour to form a uniform mixed solution.

[0011] (2) The mixed solution was naturally cooled to room temperature (25°C), and then a 10M sodium hydroxide solution was gradually added under strong stirring to adjust the pH value to 9 to generate a doped nickel hydroxide precipitate.

[0012] (3) The generated precipitate was separated by centrifugation and washed three times with deionized water. Subsequently, the dried doped nickel hydroxide powder was obtained by vacuum drying.

[0013] (4) The dried powder was calcined at 270 °C for 4 h to obtain Cu-In dual-element doped nickel oxide nanoparticles.

[0014] Example 2: Mass preparation of Cu-In dual-element doped nickel oxide nanoparticles (1) Mix 50 g of nickel powder, 2 g of copper powder and 1 g of indium powder, and dissolve them directly in 1500 ml of 15% concentrated nitric acid. The dissolution temperature is controlled at 40 °C and stirred for 1 hour to form a uniform mixed solution.

[0015] (2) The mixed solution was naturally cooled to room temperature (25°C), and then a 10M sodium hydroxide solution was gradually added under strong stirring to adjust the pH value to 9 to generate a doped nickel hydroxide precipitate.

[0016] (3) The generated precipitate was separated by centrifugation and washed three times with deionized water. Subsequently, the dried doped nickel hydroxide powder was obtained by vacuum drying.

[0017] (4) The dried powder was calcined at 270 °C for 4 h to obtain Cu-In dual-element doped nickel oxide nanoparticles.

[0018] Comparative Example 1: Preparation of undoped nickel oxide nanoparticles (1) Dissolve 5 g of nickel powder directly in 150 ml of 15% concentrated nitric acid. Control the dissolution temperature at 40 °C and stir for 1 hour to form a uniform solution.

[0019] (2) The solution was cooled naturally to room temperature (25°C), and then 10 M sodium hydroxide solution was gradually added under strong stirring to adjust the pH to 9 to generate nickel hydroxide precipitate.

[0020] (3) The resulting precipitate was separated by centrifugation and washed three times with deionized water. Subsequently, the dried nickel hydroxide powder was obtained by vacuum drying.

[0021] (4) The dried powder was calcined at 270 °C for 4 h to obtain undoped nickel oxide nanoparticles.

[0022] Testing and Characterization: (1) Particle size analysis: The nickel oxide nanoparticles prepared in Example 1 and Comparative Example 1 were analyzed by dynamic light scattering (DLS). The results showed that the average particle size of the Cu-In dual-element doped nickel oxide nanoparticles was 5.1 nm, while the average particle size of the undoped nickel oxide nanoparticles was 7.7 nm, indicating that Cu-In doping significantly reduced the particle size.

[0023] (2) Hole mobility test: The nickel oxide nanoparticles prepared in Example 1 and Comparative Example 1 were used to prepare Si / NiO / Au sandwich structure devices, and the space charge limited current (SCLC) was tested. The results showed that the hole mobility of the Cu-In dual-element doped nickel oxide nanoparticles was 1.51 cm² V -1 s -1, while the hole mobility of undoped nickel oxide nanoparticles is 0.18 cm² V -1 s -1 , indicating that Cu-In doping significantly improves the hole mobility.

Claims

1. A method for preparing metal ion-doped nickel oxide nanoparticles, characterized in that: The method comprises the following steps: (1) mixing metallic nickel powder with two or more doping metal powders, and then directly dissolving the mixture in nitric acid to form a uniform mixed solution; the doping metal is selected from copper, indium, iron, cobalt, zinc, zinc and aluminum; and the molar ratio of the total amount of the doping metal to the metallic nickel is 1:100 to 1:5; (2) The mixed solution is naturally cooled to room temperature, and then a precipitant is gradually added under strong stirring to adjust the pH value to 9-11 to generate a doped nickel hydroxide precipitate; the precipitant is a sodium hydroxide aqueous solution or ammonia water; (3) separating the generated precipitate by centrifugation, washing with deionized water, and drying to obtain doped nickel hydroxide powder; (4) The dried powder is calcined at 270°C to 350°C for 2 to 4 hours to obtain metal ion-doped nickel oxide nanoparticles.

2. The method for preparing metal ion-doped nickel oxide nanoparticles according to claim 1, wherein: In step (1), the mass percentage concentration of nitric acid is 8% to 21%.

3. The method for preparing metal ion-doped nickel oxide nanoparticles according to claim 1, wherein: In step (1), the dissolving temperature is controlled at 40°C to 60°C.

4. The method for preparing metal ion-doped nickel oxide nanoparticles according to claim 1, wherein: In step (2), the concentration of the precipitant is 7~13M.

5. The method for preparing metal ion-doped nickel oxide nanoparticles according to claim 1, wherein: In step (3), the drying method is vacuum drying or freeze drying.

6. The method for preparing metal ion-doped nickel oxide nanoparticles according to claim 5, characterized in that: In step (3), the drying time is 6 to 30 hours.

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