A preparation process of nickel oxide target for perovskite solar cells

Abstract

The invention discloses a preparation process of a nickel oxide target material for a perovskite solar cell, comprising the steps of powdering, mixing, pressing, sintering, processing and surface oxidation, wherein the nickel oxide target material is subjected to surface gas oxidation, a high voltage direct current is used to make an anion move toward an anode, and during the surface oxidation process, argon gas is used to generate argon ions in a plasma environment, and the nickel oxide target material is sputtered by utilizing the self-bias voltage generated on the surface of the nickel oxide target material to eliminate foreign molecules adsorbed on the surface, and high energy Ar plasma induces NiO and Ni(OH) 2 The low valence state to Ni ≥3+ The oxidation process of the high valence state of Ni 3+ It is beneficial to improve the semiconductor performance of the battery while selectively eliminating harmful Ni through reduction 4+ , to avoid unstable Ni 4+ Due to its strong oxidizing properties, it corrodes the perovskite layer and extends the service life of the solar cell.

Description

Technical Field

[0001] The invention relates to the technical field of nickel oxide target material preparation, and in particular to a process for preparing a nickel oxide target material for a perovskite solar cell. Background Art

[0002] Nickel oxide target is a compound target composed of nickel and oxygen. It is an important transition metal oxide with electrical conductivity and magnetism and is widely used in many fields.

[0003] A solar cell is a device that directly converts light energy into electrical energy through the photoelectric effect or photochemical reaction. Perovskite solar cells are solar cells that use perovskite-type organic metal halide semiconductors as light-absorbing materials. They belong to the third generation of solar cells and are also called new concept solar cells. When exposed to sunlight, the perovskite layer first absorbs photons to generate electron-hole pairs. Due to the difference in the binding energy of excitons in perovskite materials, these carriers either become free carriers or form excitons. Moreover, because these perovskite materials tend to have lower carrier recombination probability and higher carrier mobility, the diffusion distance and lifetime of carriers are longer.

[0004] One of the most commonly used inorganic hole transport materials in inverted perovskite solar cells (PSCs) is nickel oxide (NiO x ) because of its excellent stability and light transmittance throughout the visible spectrum. Nickel oxide (NiO x ) in Ni 4+ The oxidizing property seriously affects the uniform preparation of large-area stable devices, and the semiconductor performance is poor. For this reason, we propose a preparation process of nickel oxide target for perovskite solar cells. Summary of the invention

[0005] The technical problem to be solved by the present invention is to overcome the existing defects and provide a preparation process of nickel oxide target material for perovskite solar cells, which can induce NiO and Ni(OH) 2 The low valence state to Ni ≥3+ The oxidation process of the high valence state of Ni 3+ It is beneficial to improve the semiconductor performance of the battery while selectively eliminating harmful Ni by reduction 4+ , to avoid unstable Ni 4+ Due to its strong oxidizing property, it corrodes the perovskite layer, prolongs the service life of the solar cell, and can effectively solve the problems in the background technology.

[0006] To achieve the above object, the present invention provides the following technical solution: a process for preparing a nickel oxide target for a perovskite solar cell, comprising the following steps:

[0007] Powder making: Grind high-purity nickel oxide to obtain nickel oxide powder;

[0008] Mixing: uniformly mixing nickel oxide powder and organic binder, wherein the ratio of nickel oxide powder to organic binder is 99:1-99.9:0.1;

[0009] Pressing: Put the mixed nickel oxide powder and organic binder into an isostatic press and press them to obtain a high-strength and dense blank;

[0010] Sintering: The pressed block blank is placed in a sintering furnace for sintering. The sintering process is carried out at a hydrogen flow rate of 2 to 4 m 3 / h atmosphere;

[0011] Processing: Mechanically process the sintered bulk material to produce nickel oxide targets of corresponding shapes;

[0012] Surface oxidation: The nickel oxide target is oxidized on the surface by high-voltage direct current, and the high-voltage direct current causes the anions to move toward the anode.

[0013] As a preferred technical solution of the present invention, the purity of the high-purity nickel oxide used for powder making is greater than or equal to 99.97%.

[0014] As a preferred technical solution of the present invention, the average particle size of the nickel oxide powder obtained during the powder making is 2-40 μm.

[0015] As a preferred technical solution of the present invention, the mixing is carried out by stirring, the stirring speed is 5r / min, and the stirring time is 3-8h.

[0016] As a preferred technical solution of the present invention, the pressure during the pressing process is 150-300 MPa, and the pressure holding time is 0.5-1 h.

[0017] As a preferred technical solution of the present invention, the sintering process includes pre-sintering and high-temperature sintering, the pre-sintering temperature is 600-900°C, and the high-temperature sintering temperature is 1500-1900°C.

[0018] As a preferred technical solution of the present invention, in the surface oxidation process, argon gas is used to generate argon ions in a plasma environment, and the self-bias voltage generated on the surface of the nickel oxide target is used to sputter the nickel oxide target to eliminate foreign molecules adsorbed on the surface. The high-energy Ar plasma induces NiO and Ni(OH) 2 The low valence state to Ni≥3+ The oxidation process of the high valence state.

[0019] As a preferred technical solution of the present invention, the present invention also includes the following steps:

[0020] High-energy ion bombardment: High-energy ion bombardment is performed on the surface of the nickel oxide target to dissociate the lattice O 2− and Ni 2+ The chemical bonds between them and cause atomic displacement;

[0021] Reduction: Brønsted acid can guide NiO x The reduction reaction selectively eliminates harmful Ni 4+ And neutralize surface hydroxyl groups.

[0022] Compared with the prior art, the present invention has the following beneficial effects: by performing surface gas oxidation on the nickel oxide target, the negative ions are moved to the anode by high voltage direct current, and argon gas is used to generate argon ions in the plasma environment during the surface oxidation process, and the nickel oxide target is sputtered by utilizing the self-bias voltage generated on the surface of the nickel oxide target to eliminate foreign molecules adsorbed on the surface, and the high energy Ar plasma induces NiO and Ni(OH) 2 The low valence state to Ni ≥3+ The oxidation process of the high valence state of Ni 3+ It is beneficial to improve the semiconductor performance of the battery while selectively eliminating harmful Ni by reduction 4+ , to avoid unstable Ni 4+ Due to its strong oxidizing properties, it corrodes the perovskite layer and extends the service life of the solar cell. DETAILED DESCRIPTION

[0023] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] The present invention provides a technical solution: a preparation process of a nickel oxide target material for a perovskite solar cell, embodiment 1, comprising the following steps:

[0025] Powdering: grinding high-purity nickel oxide, the purity of which is 99.97%, to obtain nickel oxide powder, the average particle size of which is 2-10 μm;

[0026] Mixing: The nickel oxide powder and the organic binder are mixed evenly, the ratio of the nickel oxide powder to the organic binder is 99.9:0.1, and the mixing is carried out by stirring at a stirring speed of 5 r / min and a stirring time of 3 h;

[0027] Pressing: Put the mixed nickel oxide powder and organic binder into an isostatic press and press them to obtain a high-strength and dense blank. The pressure during the pressing process is 180 MPa and the holding time is 1 hour.

[0028] Sintering: The pressed block blank is placed in a sintering furnace for sintering. The sintering process is carried out at a hydrogen flow rate of 2m 3 / h atmosphere, the sintering process includes pre-sintering and high-temperature sintering, the pre-sintering temperature is 700°C, and the high-temperature sintering temperature is 1600°C;

[0029] Processing: The sintered bulk material is machined to produce nickel oxide targets of corresponding shapes;

[0030] Surface oxidation: The nickel oxide target is oxidized by high voltage direct current. The negative ions are moved to the anode by high voltage direct current. Argon gas is used to form argon ions in the plasma environment during the surface oxidation process. The self-bias voltage caused by the surface of the nickel oxide target is used to sputter the nickel oxide target to eliminate foreign molecules adsorbed on the surface. High energy Ar plasma induces NiO and Ni(OH) 2 The low valence state to Ni ≥3+ The oxidation process of the high valence state;

[0031] High-energy ion bombardment: High-energy ion bombardment is performed on the surface of the nickel oxide target to dissociate the lattice O 2− and Ni 2+ The chemical bonds between them and the resulting atomic displacements easily produce Ni under Ar plasma conditions. 2+ Vacancy defects lead to the formation of two Ni 3+ ion or a Ni 4+ To maintain charge neutrality;

[0032] Reduction: Brønsted acid can guide NiO x The reduction reaction selectively eliminates harmful Ni 4+ And neutralize the surface hydroxyl groups. The order of chemical reactivity can be obtained by Brønsted acid screening: Ni 4+ >Ni(OH) 2 >Ni 3+ >NiO, after further modification, can selectively eliminate harmful Ni 4+ and -OH, but retains the beneficial Ni 3 + and NiO.

[0033] Embodiment 2 comprises the following steps:

[0034] Powdering: Grinding high-purity nickel oxide, the purity of the high-purity nickel oxide used for powdering is 99.99%, to obtain nickel oxide powder, the average particle size of the nickel oxide powder is 15~25μm;

[0035] Mixing: Mix the nickel oxide powder and the organic binder evenly, the ratio of the nickel oxide powder to the organic binder is 99:1, and the mixing is carried out by stirring at a stirring speed of 5 r / min for 5 to 6 hours;

[0036] Pressing: The mixed nickel oxide powder and organic binder are placed in an isostatic press for pressing to obtain a high-strength and dense billet. The pressure during the pressing process is 220 MPa and the holding time is 0.9 h.

[0037] Sintering: The pressed block blank is placed in a sintering furnace for sintering. The sintering process is carried out at a hydrogen flow rate of 4m 3 / h atmosphere, the sintering process includes pre-sintering and high-temperature sintering, the pre-sintering temperature is 800°C, and the high-temperature sintering temperature is 1700°C;

[0038] Processing: Mechanically process the sintered bulk material to produce nickel oxide targets of corresponding shapes;

[0039] Surface oxidation: The nickel oxide target is oxidized by high voltage direct current. The negative ions are moved to the anode by high voltage direct current. Argon gas is used to form argon ions in the plasma environment during the surface oxidation process. The self-bias voltage caused by the surface of the nickel oxide target is used to sputter the nickel oxide target to eliminate foreign molecules adsorbed on the surface. High energy Ar plasma induces NiO and Ni(OH) 2 The low valence state to Ni ≥3+ The oxidation process of the high valence state;

[0040] High-energy ion bombardment: High-energy ion bombardment is performed on the surface of the nickel oxide target to dissociate the lattice O 2− and Ni 2+ The chemical bonds between them and the resulting atomic displacements easily produce Ni under Ar plasma conditions. 2+ Vacancy defects lead to the formation of two Ni 3+ ion or a Ni 4+ To maintain charge neutrality;

[0041] Reduction: Brønsted acid can guide NiO x The reduction reaction selectively eliminates harmful Ni 4+And neutralize the surface hydroxyl groups. The order of chemical reactivity can be obtained by Brønsted acid screening: Ni 4+ >Ni(OH) 2 >Ni 3+ >NiO, after further modification, can selectively eliminate harmful Ni 4+ and -OH, but retains the beneficial Ni 3 + and NiO.

[0042] Embodiment 3 comprises the following steps:

[0043] Powdering: Grinding high-purity nickel oxide, the purity of which is 99.97%, to obtain nickel oxide powder, the average particle size of which is 30-40 μm;

[0044] Mixing: The nickel oxide powder and the organic binder are mixed evenly, the ratio of the nickel oxide powder to the organic binder is 99.9:0.1, and the mixing is carried out by stirring at a stirring speed of 5 r / min and a stirring time of 8 h;

[0045] Pressing: Put the mixed nickel oxide powder and organic binder into an isostatic press for pressing to obtain a high-strength and dense blank. The pressure during the pressing process is 300 MPa and the holding time is 0.6 h.

[0046] Sintering: The pressed block blank is placed in a sintering furnace for sintering. The sintering process is carried out at a hydrogen flow rate of 4m 3 / h atmosphere, the sintering process includes pre-sintering and high-temperature sintering, the pre-sintering temperature is 750°C, and the high-temperature sintering temperature is 1500°C;

[0047] Processing: The sintered bulk material is machined to produce nickel oxide targets of corresponding shapes;

[0048] Surface oxidation: The nickel oxide target is oxidized by high voltage direct current. The negative ions are moved to the anode by high voltage direct current. Argon gas is used to form argon ions in the plasma environment during the surface oxidation process. The self-bias voltage caused by the surface of the nickel oxide target is used to sputter the nickel oxide target to eliminate foreign molecules adsorbed on the surface. High energy Ar plasma induces NiO and Ni(OH) 2 The low valence state to Ni ≥3+ The oxidation process of the high valence state;

[0049] High-energy ion bombardment: High-energy ion bombardment is performed on the surface of the nickel oxide target to dissociate the lattice O 2− and Ni 2+ The chemical bonds between them and the resulting atomic displacements easily produce Ni under Ar plasma conditions.2+ Vacancy defects lead to the formation of two Ni 3+ ion or a Ni 4+ To maintain charge neutrality;

[0050] Reduction: Brønsted acid can guide NiO x The reduction reaction selectively eliminates harmful Ni 4+ And neutralize the surface hydroxyl groups. The order of chemical reactivity can be obtained by Brønsted acid screening: Ni 4+ >Ni(OH) 2 >Ni 3+ >NiO, after further modification, can selectively eliminate harmful Ni 4+ and -OH, but retains the beneficial Ni 3 + and NiO.

[0051] The undisclosed parts in the present invention are all prior art, and their specific structures, materials and working principles are not described in detail. Although the embodiments of the present invention have been shown and described, it is understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A process for preparing nickel oxide target for perovskite solar cells, characterized in that: The following steps are involved: Powder making: Grind high-purity nickel oxide to obtain nickel oxide powder; Mixing: uniformly mixing nickel oxide powder and organic binder, wherein the ratio of nickel oxide powder to organic binder is 99:1-99.9:0.1; Pressing: Put the mixed nickel oxide powder and organic binder into an isostatic press and press them to obtain a high-strength and dense blank; Sintering: The pressed block blank is placed in a sintering furnace for sintering. The sintering process is carried out at a hydrogen flow rate of 2 to 4 m 3 / h atmosphere; Processing: The sintered bulk material is machined to produce nickel oxide targets of corresponding shapes; Surface oxidation: The nickel oxide target is oxidized by high voltage direct current. The negative ions are moved to the anode by high voltage direct current. Argon gas is used to form argon ions in the plasma environment during the surface oxidation process. The self-bias voltage caused by the surface of the nickel oxide target is used to sputter the nickel oxide target to eliminate foreign molecules adsorbed on the surface. High energy Ar plasma induces NiO and Ni(OH) 2 The low valence state to Ni ≥3+ The oxidation process of the high valence state; High-energy ion bombardment: High-energy ion bombardment is performed on the surface of the nickel oxide target to dissociate the lattice O 2− and Ni 2+ The chemical bonds between them and cause atomic displacement; Reduction: Brønsted acid can guide NiO x The reduction reaction selectively eliminates harmful Ni 4+ And neutralize surface hydroxyl groups.

2. The process for preparing a nickel oxide target for a perovskite solar cell according to claim 1, characterized in that: The purity of the high-purity nickel oxide used in the powder making is greater than or equal to 99.97%.

3. The process for preparing a nickel oxide target for a perovskite solar cell according to claim 2, characterized in that: The average particle size of the nickel oxide powder obtained during the powder making process is 2-40 μm.

4. The process for preparing a nickel oxide target for a perovskite solar cell according to claim 1, characterized in that: The mixing is carried out by stirring, the stirring speed is 5 r / min, and the stirring time is 3 to 8 hours.

5. The process for preparing a nickel oxide target for a perovskite solar cell according to claim 1, characterized in that: The pressure during the pressing process is 150-300 MPa, and the pressure holding time is 0.5-1 h.

6. The process for preparing a nickel oxide target for a perovskite solar cell according to claim 1, characterized in that: The sintering process includes pre-sintering and high-temperature sintering, the pre-sintering temperature is 600-900°C, and the high-temperature sintering temperature is 1500-1900°C.