Modified nickel oxide target material and preparation method thereof

Abstract

The invention belongs to the technical field of target materials, and particularly relates to a modified nickel oxide target material and a preparation method thereof. The invention provides a modified nickel oxide target material, the chemical formula is NiMOx, and x is greater than 1 and less than 2; m comprises modified doped metal elements, and the modified doped metal elements comprise monovalent metal and metal with the valence higher than bivalent; the monovalent metal comprises Li and / or Ag; the metal with the valence higher than bivalent comprises one or more of Mg, Mn, Co, Cu, Zn, Ti, V, Fe, In, Sn, Al, Ca, Sb and Ba. The energy level structure of nickel oxide is regulated and controlled by adopting modified ion doping and sintering-assisting elements, the nickel vacancy concentration is increased, the material conductivity is improved, the sintering temperature is reduced, and the sintering density of the target material is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of target materials, and particularly relates to a modified nickel oxide target material and a preparation method thereof. Background Art

[0002] Nickel oxide is a wide bandgap p-type semiconductor material with high transmittance in the visible light range. The valence band top energy level is around -5.1eV, which matches the perovskite energy level and is suitable for use as a hole transport layer material for perovskite cells.

[0003] The conductivity of intrinsic nickel oxide is less than 10 at room temperature. -11 S cm -1 Although the nickel oxide after film formation exhibits the properties of a p-type semiconductor due to the presence of Ni vacancies, its poor conductivity will seriously affect the photovoltaic performance of the perovskite cell. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a modified nickel oxide target material and a preparation method thereof. The modified nickel oxide target material provided by the present invention has good conductivity after film formation.

[0005] The present invention provides a modified nickel oxide target material, the chemical formula of which is NiMO x , where 1﹤x﹤2;

[0006] The M includes modified doped metal elements, and the modified doped metal elements include monovalent metals and divalent or higher metals; the monovalent metals include Li and / or Ag; the divalent or higher metals include one or more of Mg, Mn, Co, Cu, Zn, Ti, V, Fe, In, Sn, Al, Ca, Sb and Ba.

[0007] Preferably, in the modified nickel oxide target, the percentage of Ni in the total atoms of Ni and M is 80-90%, and the percentage of M in the total atoms of Ni and M is 10-20%.

[0008] Preferably, the M further includes a sintering aid element, and the sintering aid element includes Na and / or Si.

[0009] Preferably, the percentage of the sintering aid element in the total atoms of Ni and M is 0-10%, and is not 0.

[0010] The present invention also provides a method for preparing the modified nickel oxide target material described in the above technical solution, comprising the following steps:

[0011] Mixing the nickel source and the modified dopant and performing ball milling to obtain a first powder;

[0012] Mixing the first powder, a dispersant, water, a binder and a defoamer, and drying the obtained slurry to obtain a second powder;

[0013] The second powder is pressed into a shape, and the obtained green blank is sintered to obtain a modified nickel oxide target.

[0014] Preferably, the nickel source includes nickel element, nickel oxide, nickel hydroxide or nickel inorganic salt; the nickel oxide includes NiO or Ni2O3, and the nickel inorganic salt includes one or more of nickel sulfate, nickel chloride, nickel nitrate and nickel acetate.

[0015] Preferably, the modified dopant includes one or more of lithium carbonate, silver oxide, magnesium hydroxide, magnesium oxide, manganese carbonate, cobalt hydroxide, copper oxide, zinc oxide, titanium dioxide, vanadium pentoxide, iron nitrate, indium oxide, tin oxide, aluminum powder, calcium hydroxide, antimony oxide and barium carbonate.

[0016] Preferably, a sintering aid is added when the nickel source and the modified dopant are mixed, and the sintering aid includes sodium bicarbonate and / or silicon dioxide.

[0017] Preferably, the dispersant includes one or more of ethanol, oxalic acid, nitric acid, polyethylene glycol, sodium citrate, sodium pyrophosphate and sodium polyphosphate.

[0018] Preferably, the binder includes one or more of vinyl acetate, polyvinyl alcohol, epoxy resin, epoxy acrylate and phenolic resin; the defoamer includes one or more of sodium phosphate, polyacrylate, sodium polyacrylate, hydroxymethyl cellulose and polyacrylamide.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention provides a modified nickel oxide target material, the chemical formula of which is NiMO x , wherein 1﹤x﹤2; the M comprises a modified doped metal element, and the modified doped metal element comprises a monovalent metal and a divalent or higher metal; the monovalent metal comprises Li and / or Ag; the divalent or higher metal comprises one or more of Mg, Mn, Co, Cu, Zn, Ti, V, Fe, In, Sn, Al, Ca, Sb and Ba.

[0021] The modified nickel oxide target material of the present invention comprises a monovalent metal and a divalent or higher metal. The monovalent metal has a smaller ion radius and is easy to enter the NiO lattice to replace Ni 2+ ions, leading to Ni 3+The ion concentration increases, thereby reducing the resistivity of the NiO film and improving its conductivity; divalent or higher metals have strong oxygen binding force, which can significantly increase the oxygen content of the target material, increase the concentration of nickel vacancy defects, and improve conductivity. The present invention uses ion doping to improve the energy level structure of nickel oxide materials, optimize the energy level matching of perovskite cells, increase the nickel vacancy concentration, increase the carrier concentration and hole mobility, improve the material conductivity, and lay the foundation for realizing high-efficiency photovoltaic devices.

[0022] The present invention also provides a method for preparing the modified nickel oxide target material described in the above technical solution, and the preparation method is simple. Furthermore, the present invention adds a sintering aid to reduce the sintering temperature, shorten the sintering time, inhibit grain growth, and increase the sintering density of the target material.

[0023] The data of the embodiment show that doping with 5mol% Li and 5mol% Ag can make NiMO x The target material exhibits excellent performance, with a body resistance as low as 12.8Ω, which is significantly improved compared to conventional nickel oxide targets. At the same time, the melting point of Ag2O is about 300°C, and the lower melting point can achieve liquid phase sintering, promoting NiMO x The target material is sintered and densified, and the relative density is increased to 99.5%; Mg has excellent stability, but is not conducive to sintering. By doping Mg with NiO to form a solid solution, the growth of NiO grains can be inhibited, the chemical stability of NiO can be improved, and the life of the perovskite battery can be extended; and, as can be seen from the XRD diffraction pattern, doping with Li, Ag, and Mg elements does not affect the crystal structure of NiO, and therefore has almost no effect on the transmittance of the NiO film, ensuring the high efficiency of the photovoltaic performance of the perovskite battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 This is a SEM image of the modified nickel oxide target prepared in Example 1;

[0026] Figure 2 This is a SEM image of the nickel oxide target prepared in Comparative Example 1;

[0027] Figure 3 XRD patterns of the modified nickel oxide target prepared in Example 1 and the nickel oxide target prepared in Comparative Example 1. DETAILED DESCRIPTION

[0028] The present invention provides a modified nickel oxide target material, the chemical formula of which is NiMO x , where 1﹤x﹤2;

[0029] The M includes modified doped metal elements, and the modified doped metal elements include monovalent metals and divalent or higher metals; the monovalent metals include Li and / or Ag; the divalent or higher metals include one or more of Mg, Mn, Co, Cu, Zn, Ti, V, Fe, In, Sn, Al, Ca, Sb and Ba.

[0030] In the present invention, the percentage of Ni in the modified nickel oxide target to the total atoms of Ni and M is preferably 80-90%, specifically 85%, and the percentage of M to the total atoms of Ni and M is preferably 10-20%, specifically 15%.

[0031] In the present invention, the monovalent metal is preferably Li and Ag, and Ag also has the function of aiding sintering. The divalent or higher metal is preferably one or more of Mg, Cu and Sb. When the divalent or higher metal is Al, Ca, Sb or Ba, it also has the function of aiding sintering.

[0032] In the present invention, the modified doping metal elements preferably include Li, Ag and Mg, or Li and Cu, or Li, Ag and Cu, or Li, Ag and Sb, or Ag, Mg and Sb, or Li, Mg and Ca; the percentages of Li, Ag and Mg in the total atoms of Ni and M are preferably 5%, 5% and 5%, respectively.

[0033] In the present invention, the percentage of the modified doping metal element in the total atoms of Ni and M is preferably 10-15%.

[0034] In the present invention, the M preferably further includes a sintering aid element, and the sintering aid element preferably includes Na and / or Si, and more preferably Si.

[0035] In the present invention, the percentage of the sintering aid element to the total atoms of Ni and M is preferably 0-10%, and is not 0, and can be specifically 5%.

[0036] The relative density of the modified nickel oxide target material of the present invention is ≥97.5%; when the sample size is: diameter Φ76.2*3mm, the body resistance is as low as 12.8Ω, and the conductivity is good.

[0037] The present invention also provides a method for preparing the modified nickel oxide target material described in the above technical solution, comprising the following steps:

[0038] Mixing the nickel source and the modified dopant and performing ball milling to obtain a first powder;

[0039] Mixing the first powder, a dispersant, water, a binder and a defoamer, and drying the obtained slurry to obtain a second powder;

[0040] The second powder is pressed into a shape, and the obtained green body is sintered to obtain a modified nickel oxide target.

[0041] In the present invention, unless otherwise specified, the materials and equipment used are commercially available products in the art.

[0042] The present invention mixes a nickel source and a modified dopant and performs ball milling to obtain a first powder.

[0043] In the present invention, the nickel source preferably includes nickel element, nickel oxide, nickel hydroxide or nickel inorganic salt; the nickel element is preferably nickel powder, the nickel oxide preferably includes NiO (nickel oxide) or Ni2O3 (nickel trioxide), the nickel hydroxide is nickel hydroxide, and the nickel inorganic salt preferably includes one or more of nickel sulfate, nickel chloride, nickel nitrate and nickel acetate; the purity of the nickel source is preferably above 99.99%.

[0044] In the present invention, the modified dopant preferably includes one or more of lithium carbonate, silver oxide, magnesium hydroxide, magnesium oxide, manganese carbonate (MnCO3), cobalt hydroxide, copper oxide, zinc oxide, titanium dioxide, vanadium pentoxide, iron nitrate, indium oxide, tin oxide, aluminum powder, calcium hydroxide, antimony oxide and barium carbonate; specifically, it can be lithium carbonate and magnesium hydroxide, or lithium carbonate and copper oxide. The purity of the modified dopant is preferably above 99.99%.

[0045] In the present invention, when the nickel source and the modified dopant are mixed, a sintering aid is preferably added, and the sintering aid preferably includes sodium bicarbonate and / or silicon dioxide, specifically silicon dioxide. The purity of the sintering aid is preferably above 99.99%.

[0046] In an embodiment of the present invention, the first powder preferably comprises components in the following molar ratios: the molar ratio of nickel oxide, lithium carbonate, magnesium hydroxide and silver oxide is 8.5:0.25:0.5:0.25, or the molar ratio of nickel oxide, lithium carbonate, copper oxide and silicon dioxide is 8.5:0.25:0.5:0.5, or the molar ratio of nickel oxide, lithium carbonate, copper oxide and silver oxide is 8.5:0.25:0.5:0.25, or the molar ratio of nickel oxide, lithium carbonate, silver oxide and antimony oxide is 8.5:0.25:0.25:0.25, or the molar ratio of nickel oxide, magnesium oxide, silver oxide and antimony oxide is 8.5:0.5:0.25:0.25, or the molar ratio of nickel oxide, lithium carbonate, magnesium oxide and calcium hydroxide is 8.5:0.25:0.5:0.5.

[0047] In the present invention, the rotation speed of the ball mill is preferably 100-600 rpm, specifically 100 rpm, 300 rpm, 400 rpm, 500 rpm or 600 rpm, and the time is preferably 1-6 h, specifically 1 h, 3 h, 5 h or 6 h; the particle size (D50) of the first powder is preferably 0.8-2 μm, specifically 0.8 μm, 1 μm, 1.2 μm, 1.5 μm or 2 μm.

[0048] After obtaining the first powder, the present invention mixes the first powder, a dispersant, water, a binder and a defoamer, and dries the obtained slurry to obtain a second powder.

[0049] In the present invention, the dispersant preferably includes one or more of ethanol, oxalic acid, nitric acid, polyethylene glycol, sodium citrate, sodium pyrophosphate and sodium polyphosphate, specifically ethanol and polyethylene glycol, and the mass ratio of ethanol to polyethylene glycol is preferably 4:1 or 25:2.

[0050] In the present invention, the added amount of the dispersant is preferably 0-10% of the mass of the first powder, and is not 0, specifically 2.5% or 2.7%.

[0051] In the present invention, the mass ratio of the first powder to water is preferably 1:1.

[0052] In the present invention, the first powder, dispersant and water are preferably first mixed to obtain a first slurry, and then mixed with a binder and a defoaming agent for a second time; the first mixing preferably includes dispersion and sand milling, and the dispersion is preferably carried out under stirring, the rotation speed is preferably 1000rpm, and the time is preferably 1h; the rotation speed of the sand milling is preferably 500-2500rpm, specifically 500rpm, 2000rpm or 2500rpm, and the time is preferably 2-24h, specifically 2h, 4h, 6h or 24h; the particle size (D50) of the first slurry is preferably 0.1-0.6μm, specifically 0.1μm, 0.2μm, 0.25μm, 0.3μm, 0.4μm or 0.6μm.

[0053] In the present invention, the binder preferably includes one or more of vinyl acetate, polyvinyl alcohol, epoxy resin, epoxy acrylate and phenolic resin, specifically polyvinyl alcohol and vinyl acetate, or polyvinyl alcohol and epoxy acrylate. The mass ratio of polyvinyl alcohol to vinyl acetate is preferably 5:1, and the mass ratio of polyvinyl alcohol to epoxy acrylate is preferably 5:1.

[0054] In the present invention, the mass of the binder is preferably 0-10% of the mass of the first powder, and is not 0, and specifically can be 0.4%, 0.6%, 1.1%, 1.2% or 1.5%.

[0055] In the present invention, the defoaming agent preferably includes one or more of sodium phosphate, polyacrylate, sodium polyacrylate, hydroxymethyl cellulose and polyacrylamide.

[0056] In the present invention, the mass of the defoaming agent is preferably 0-10% of the mass of the first powder, and is not 0, and can be specifically 0.05%, 0.1% or 0.2%.

[0057] In the present invention, the first powder, dispersant, water, binder and defoamer are preferably mixed by stirring, the stirring speed is preferably 1000 rpm, and the stirring time is preferably 1 to 2 hours.

[0058] In the present invention, the drying is preferably spray drying, and the inlet temperature of the spray drying is preferably 180-300°C, specifically 180°C, 245°C, 250°C, 265°C, 280°C or 300°C, and the outlet temperature is preferably 85-105°C, specifically 85°C or 105°C.

[0059] In the present invention, the drying preferably also includes crushing and screening, the crushing is preferably air flow crushing, the speed of the classifying wheel of the air flow crushing is preferably 50 to 300 rpm, specifically 50 rpm, 80 rpm, 100 rpm or 300 rpm; the particle size (D97) of the second powder obtained by the screening is preferably <50 μm, more preferably <40 μm.

[0060] After obtaining the second powder, the present invention presses the second powder into a shape, and sintering the obtained green billet to obtain a modified nickel oxide target.

[0061] In the present invention, the press forming preferably includes hydraulic forming, cold isostatic pressing or hot isostatic pressing. The conditions of the cold isostatic pressing include: the pressure is preferably 200-250MPa, specifically 200MPa, 220MPa or 250MPa, and the holding time is preferably 30-60min, specifically 30min, 50min or 60min; the conditions of the hydraulic forming preferably include: the pressure is 60MPa and the holding time is 50min.

[0062] In the present invention, the sintering atmosphere is preferably an oxygen-containing atmosphere, and the volume proportion of oxygen in the oxygen-containing atmosphere is preferably 90% to 100%.

[0063] In the present invention, the sintering procedure includes: first heating to a first temperature at a first heating rate, and then heating to a second temperature at a second heating rate; the first heating rate is preferably 0.5-2°C / min, specifically 1°C / min, the first temperature is preferably 400-700°C, specifically 400°C, 600°C, 650°C or 700°C, and the holding time is preferably 1-6h, specifically 1h, 4h or 6h; the second heating rate is preferably 0.5-2°C / min, the second temperature is preferably 950-1800°C, specifically 950°C, 1250°C, 1300°C, 1350°C, 1450°C, 1500°C or 1550°C, and the holding time is preferably 6-72h, specifically 6h, 28h, 36h, 54h or 72h. The first temperature gradient is the debinding process, which oxidizes and discharges the added organic matter such as dispersant, binder, defoamer, etc. from the green body. The second temperature is the temperature at which the target material undergoes liquid phase sintering and densification.

[0064] In the present invention, the sintering preferably includes cooling, and the present invention has no special requirements for the cooling method.

[0065] The present invention introduces doping ions to change the electronic structure and lattice constant of nickel oxide, thereby adjusting the energy level structure of the material and regulating its optical and electrical properties. Single element doping can usually improve the conductivity of nickel oxide, but it is difficult to achieve the coordinated optimization of multiple properties such as light transmittance, energy band structure, and stability. The present invention uses a variety of ion dopants to assist sintering aids to effectively utilize the doping characteristics of different ions, reduce the sintering temperature, increase the sintering density, and achieve comprehensive regulation of the performance of nickel oxide materials to meet the performance requirements of different perovskite materials.

[0066] In order to further illustrate the present invention, the modified nickel oxide target material and the preparation method thereof provided by the present invention are described in detail below in conjunction with the accompanying drawings and examples, but they should not be construed as limiting the protection scope of the present invention.

[0067] Example 1

[0068] The preparation method of the modified nickel oxide target is as follows:

[0069] Step 1: nickel oxide (NiO) powder, lithium carbonate powder, magnesium hydroxide powder, and silver oxide powder with a purity greater than 99.99% are mixed in a molar ratio of 8.5:0.25:0.5:0.25, and then transferred into a planetary ball mill and ball-milled at 500 rpm for 6 h to obtain a mixed powder A with D50 = 1 μm;

[0070] Step 2: Take 10 kg of the mixed powder A obtained in step 1, add 200 g of ethanol, 50 g of polyethylene glycol and 10 kg of pure water, disperse at 1000 rpm for 1 h, transfer to a sand mill, and sand grind at 2000 rpm for 6 h to obtain slurry B with D50 = 0.2 μm;

[0071] Step 3: Add 100 g of polyvinyl alcohol, 20 g of vinyl acetate and 10 g of polyacrylate to the slurry B obtained in step 2, and disperse at 1000 rpm for 1 hour to obtain slurry C;

[0072] Step 4: spray drying the slurry C obtained in step 3 at an inlet temperature of 250°C and an outlet temperature of 105°C, and then air flow pulverizing the dried powder at a classifying wheel speed of 80 rpm to obtain a powder D with D97 < 50 μm;

[0073] Step 5: The powder D obtained in step 4 is placed into a cold isostatic pressing mold for pressing at a pressure of 250 MPa and a holding time of 30 min to prepare a modified nickel oxide target blank;

[0074] Step 6: Place the blank obtained in step 5 into a sintering furnace, heat it to 600°C at a rate of 1°C / min under an oxygen atmosphere and keep it warm for 6 hours, then heat it to 1550°C at a rate of 0.5°C / min and keep it warm for 72 hours. After cooling, demold it and machine it according to the drawing to obtain a modified nickel oxide target.

[0075] Example 2

[0076] The preparation method of the modified nickel oxide target is as follows:

[0077] Step 1: nickel oxide powder, lithium carbonate powder, copper oxide powder and silicon dioxide powder with a purity greater than 99.99% are mixed in a molar ratio of 8.5:0.25:0.5:0.5, and then transferred into a planetary ball mill and ball-milled at 500 rpm for 6 hours to obtain a mixed powder A with D50=1 μm;

[0078] Step 2: Take 10 kg of the mixed powder A obtained in step 1, add 200 g of ethanol, 50 g of polyethylene glycol and 10 kg of pure water, disperse at 1000 rpm for 1 h, transfer to a sand mill, and sand grind at 2000 rpm for 6 h to obtain slurry B with D50 = 0.2 μm;

[0079] Step 3: Add 100 g of polyvinyl alcohol, 20 g of vinyl acetate and 10 g of polyacrylate to the slurry B obtained in step 2, and disperse at 1000 rpm for 1 hour to obtain slurry C;

[0080] Step 4: spray drying the slurry C obtained in step 3 at an inlet temperature of 280°C and an outlet temperature of 105°C, and then air flow crushing the dried powder at a classifying wheel speed of 80 rpm to obtain a powder D with D97 < 50 μm;

[0081] Step 5: The powder D obtained in step 4 is loaded into a cold isostatic pressing mold for pressing at a pressure of 200 MPa and a holding time of 50 min to prepare a modified nickel oxide target blank;

[0082] Step 6: Place the blank obtained in step 5 into a sintering furnace, heat it to 700°C at a rate of 1°C / min under an oxygen atmosphere and keep it for 4 hours, then heat it to 1500°C at a rate of 0.5°C / min and keep it for 36 hours. After cooling, demold it and machine it according to the drawing to obtain a modified nickel oxide target.

[0083] Example 3

[0084] The preparation method of the modified nickel oxide target is as follows:

[0085] Step 1: nickel oxide powder, lithium carbonate powder, copper oxide powder and silver oxide powder with a purity greater than 99.99% are mixed in a molar ratio of 8.5:0.25:0.5:0.25, and then transferred into a planetary ball mill and ball milled at 300 rpm for 3 hours to obtain a mixed powder A with D50=1.5 μm;

[0086] Step 2: Take 10 kg of the mixed powder A obtained in step 1, add 200 g of ethanol, 50 g of polyethylene glycol and 10 kg of pure water, disperse at 1000 rpm for 1 hour, transfer to a sand mill, and sand grind at 2000 rpm for 4 hours to obtain slurry B with D50 = 0.3 μm;

[0087] Step 3: Add 100 g of polyvinyl alcohol, 20 g of epoxy acrylate and 10 g of sodium polyacrylate to the slurry B obtained in step 2, and disperse at 1000 rpm for 1 hour to obtain slurry C;

[0088] Step 4: spray drying the slurry C obtained in step 3 at an inlet temperature of 265°C and an outlet temperature of 105°C, and then air flow pulverizing the dried powder at a classifying wheel speed of 80 rpm to obtain a powder D with D97 < 50 μm;

[0089] Step 5: Powder D obtained in step 4 is loaded into a stainless steel hot isostatic pressing mold (wall thickness 3 mm, powder filling rate greater than 40%), and then welded and packaged after compaction;

[0090] Step 6: Place the blank obtained in step 5 into a hot isostatic pressing furnace (pressure 150 MPa), and under a nitrogen atmosphere, heat it to 600°C at a rate of 1°C / min and keep it for 6 hours, then heat it to 1250°C at a rate of 0.5°C / min and keep it for 6 hours. After cooling, demold it and machine it according to the drawing to obtain a modified nickel oxide target.

[0091] Example 4

[0092] The preparation method of the modified nickel oxide target is as follows:

[0093] Step 1: nickel oxide powder, lithium carbonate powder, silver oxide powder, and antimony oxide (Sb2O3) powder with a purity greater than 99.99% are mixed in a molar ratio of 8.5:0.25:0.25:0.25, and then transferred into a planetary ball mill and ball-milled at 400 rpm for 5 h to obtain a mixed powder A with a D50 of 1.2 μm;

[0094] Step 2: Take 10 kg of the mixed powder A obtained in step 1, add 200 g of ethanol, 50 g of polyethylene glycol and 10 kg of pure water, disperse at 1000 rpm for 1 h, transfer to a sand mill, and sand grind at 2000 rpm for 6 h to obtain slurry B with D50 = 0.25 μm;

[0095] Step 3: Add 100 g of polyvinyl alcohol, 20 g of vinyl acetate and 10 g of polyacrylate to the slurry B obtained in step 2, and disperse at 1000 rpm for 1 hour to obtain slurry C;

[0096] Step 4: spray drying the slurry C obtained in step 3 at an inlet temperature of 265°C and an outlet temperature of 105°C, and then air flow pulverizing the dried powder at a classifying wheel speed of 80 rpm to obtain a powder D with D97 < 40 μm;

[0097] Step 5: Powder D obtained in step 4 is placed in a cold isostatic pressing mold for pressing at a pressure of 220 MPa and a holding time of 60 min to prepare a modified nickel oxide target blank;

[0098] Step 6: Place the blank obtained in step 5 into a sintering furnace, heat it to 700°C at a rate of 1°C / min under an oxygen atmosphere and keep it for 6 hours, then heat it to 1450°C at a rate of 0.5°C / min and keep it for 54 hours. After cooling, demold it and machine it according to the drawing to obtain a modified nickel oxide target.

[0099] Example 5

[0100] The preparation method of the modified nickel oxide target is as follows:

[0101] Step 1: nickel oxide powder, magnesium oxide powder, silver oxide powder and antimony oxide powder with a purity greater than 99.99% are mixed in a molar ratio of 8.5:0.5:0.25:0.25, and then transferred into a planetary ball mill and ball-milled at 600 rpm for 3 h to obtain a mixed powder A with a D50 of 0.8 μm;

[0102] Step 2: Take 10 kg of the mixed powder A obtained in step 1, add 250 g of ethanol, 20 g of polyethylene glycol and 10 kg of pure water, disperse at 1000 rpm for 1 h, transfer to a sand mill, and sand grind at 2000 rpm for 2 h to obtain slurry B with D50 = 0.4 μm;

[0103] Step 3: Add 60 g of vinyl acetate and 10 g of polyacrylate to the slurry B obtained in step 2, and disperse at 1000 rpm for 2 h to obtain slurry C;

[0104] Step 4: spray drying the slurry C obtained in step 3 at an inlet temperature of 245°C and an outlet temperature of 105°C, and then air flow pulverizing the dried powder at a classifying wheel speed of 80 rpm to obtain a powder D with D97 < 50 μm;

[0105] Step 5: The powder D obtained in step 4 is loaded into a hydraulic mold for pressing at a pressure of 60 MPa and a holding time of 50 min to prepare a modified nickel oxide target blank;

[0106] Step 6: Place the blank obtained in step 5 into a sintering furnace, heat it to 600°C at a rate of 1°C / min under an oxygen atmosphere and keep it for 6 hours, then heat it to 1300°C at a rate of 0.5°C / min and keep it for 36 hours. After cooling, demold it and machine it according to the drawing to obtain a modified nickel oxide target.

[0107] Example 6

[0108] The preparation method of the modified nickel oxide target is as follows:

[0109] Step 1: nickel oxide powder, lithium carbonate powder, magnesium oxide powder and calcium hydroxide with a purity greater than 99.99% are mixed in a molar ratio of 8.5:0.25:0.5:0.5, and then transferred into a planetary ball mill and ball-milled at 500 rpm for 6 hours to obtain a mixed powder A with D50=1 μm;

[0110] Step 2: Take 10 kg of the mixed powder A obtained in step 1, add 200 g of ethanol, 50 g of polyethylene glycol and 10 kg of pure water, disperse at 1000 rpm for 1 h, transfer to a sand mill, and sand grind at 2000 rpm for 6 h to obtain slurry B with D50 = 0.2 μm;

[0111] Step 3: Add 100 g of polyvinyl alcohol, 20 g of vinyl acetate and 10 g of polyacrylate to the slurry B obtained in step 2, and disperse at 1000 rpm for 1 hour to obtain slurry C;

[0112] Step 4: spray drying the slurry C obtained in step 3 at an inlet temperature of 265°C and an outlet temperature of 105°C, and then air flow crushing the dried powder at a classifying wheel speed of 100 rpm to obtain a powder D with D97 < 40 μm;

[0113] Step 5: Powder D obtained in step 4 is placed in a cold isostatic pressing mold for pressing at a pressure of 250 MPa and a holding time of 50 min to prepare a modified nickel oxide target blank;

[0114] Step 6: Place the blank obtained in step 5 into a sintering furnace, heat it to 650°C at a rate of 1°C / min under an oxygen atmosphere and keep it for 6 hours, then heat it to 1350°C at a rate of 0.5°C / min and keep it for 28 hours. After cooling, demold it and machine it according to the drawing to obtain a modified nickel oxide target.

[0115] Comparative Example 1

[0116] The difference from Example 1 is that lithium carbonate powder, magnesium hydroxide powder and silver oxide powder are not added, and the other steps are the same.

[0117] Comparative Example 2

[0118] The difference from Example 1 is that lithium carbonate powder is not added, and the other steps are the same.

[0119] Comparative Example 3

[0120] The difference from Example 1 is that no silver oxide powder is added, and the remaining steps are the same.

[0121] Comparative Example 4

[0122] The difference from Example 1 is that magnesium hydroxide powder is not added, and the remaining steps are the same.

[0123] Test Example 1 Target Material Test

[0124] Density test: The Archimedes drainage method is used for testing. The relative density refers to the ratio of the density of the modified nickel oxide target to the theoretical density of pure nickel oxide. The theoretical density of pure nickel oxide is 6.67 g / cm 3 .

[0125] Purity test: Inductively coupled plasma spectrometer is used for testing. Purity refers to the total mass proportion of Ni, doping elements and oxygen elements in the modified nickel oxide target.

[0126] Square resistance test: The test is carried out using a four-probe square resistance tester, and the size of the test sample is: diameter Φ76.2*3mm.

[0127] Morphology test: The test was carried out using a German Zeiss field emission scanning electron microscope.

[0128] Structural test: The test was carried out using Japan Rigaku XRD diffractometer.

[0129] The test results are shown in Table 1:

[0130] Table 1 Test results of modified nickel oxide targets of Examples 1 to 6 and nickel oxide targets of Comparative Examples 1 to 4

[0131]

[0132] It can be seen from the data in Table 1 that the relative density of the pure nickel oxide target sintered by conventional sintering process in Comparative Example 1 is only 83.6%, the bulk resistance exceeds the instrument range, the sintering density is low, and the target cracks after sintering. The modified nickel oxide target prepared by the preparation method of the present invention has a maximum relative density of 99.5%, a bulk resistance as low as 12.82Ω, and a significantly improved conductivity. Comparing the data of Example 1 with Comparative Examples 2 to 3, Example 1 has a smaller grain size and a higher relative density, indicating that doping Li and Ag are beneficial to improving the sintering density and conductivity of the target. Comparing the data of Example 1 and Comparative Example 4, it is shown that doping Mg can inhibit grain growth, and the resulting grain size is small, which is beneficial to improving the mechanical strength of the target, enabling the target to withstand higher power sputtering requirements and improve sputtering efficiency.

[0133] Figure 1 This is a SEM image of the modified nickel oxide target prepared in Example 1; Figure 2 This is an SEM image of the nickel oxide target prepared in Comparative Example 1; it can be seen that the target prepared in Example 1 has a high density, the grains are tightly bonded, there is almost no pores, and the grain size is less than 10 μm, while the target prepared in Comparative Example 1 has a high porosity, the grains are only bonded by point contact, and the relative density is low.

[0134] Figure 3 XRD diagrams of the modified nickel oxide target prepared in Example 1 and the nickel oxide target prepared in Comparative Example 1. Figure 3 It can be seen that Example 1 does not show any diffraction peak other than NiO, and the doped Li, Ag, and Mg elements do not affect the crystal structure of NiO, proving that the doped elements have all entered the nickel oxide lattice, thus having almost no effect on the light transmittance of the NiO film, thus ensuring the high efficiency of the photovoltaic performance of the perovskite cell.

[0135] Example 1 uses Li, Ag, and Mg ions as modified dopants. Li and Ag are monovalent metal ions. Doping to replace nickel positions can increase the Ni vacancy concentration and generate additional holes. These holes form carriers, which help to improve the conductivity of the target material. The present invention uses the technical means of metal element doping to regulate the energy level structure of nickel oxide materials, optimize the energy level matching of perovskite batteries, increase the nickel vacancy concentration, increase the carrier concentration and hole mobility, improve the material conductivity, and lay the foundation for realizing high-efficiency photovoltaic devices; by adding a sintering aid, the sintering temperature can be reduced, the sintering time can be shortened, the grain growth can be controlled, and the sintering density of the target material can be increased.

[0136] Although the above-mentioned embodiments have made a detailed description of the present invention, they are only some embodiments of the present invention, rather than all embodiments. People can also obtain other embodiments based on the embodiments of the present invention without creative work, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A modified nickel oxide target, characterized in that: The chemical formula is NiMO x , where 1﹤x﹤2; The M includes modified doped metal elements, and the modified doped metal elements include monovalent metals and divalent or higher metals; the monovalent metals include Li and / or Ag; the divalent or higher metals include one or more of Mg, Mn, Co, Cu, Zn, Ti, V, Fe, In, Sn, Al, Ca, Sb and Ba.

2. The modified nickel oxide target according to claim 1, characterized in that: In the modified nickel oxide target material, the percentage of Ni in the total atoms of Ni and M is 80-90%, and the percentage of M in the total atoms of Ni and M is 10-20%.

3. The modified nickel oxide target according to claim 1, characterized in that The M further includes a sintering aid element, and the sintering aid element includes Na and / or Si.

4. The modified nickel oxide target according to claim 3, characterized in that: The percentage of the sintering aid element to the total atoms of Ni and M is 0-10%, and is not zero.

5. The method for preparing a modified nickel oxide target according to any one of claims 1 to 4, characterized in that: The following steps are involved: The nickel source and the modified dopant are mixed and ball-milled to obtain a first powder; Mixing the first powder, a dispersant, water, a binder and a defoamer, and drying the obtained slurry to obtain a second powder; The second powder is pressed into a shape, and the obtained green blank is sintered to obtain a modified nickel oxide target.

6. The preparation method according to claim 5, characterized in that: The nickel source includes nickel element, nickel oxide, nickel hydroxide or nickel inorganic salt; the nickel oxide includes NiO or Ni2O3, and the nickel inorganic salt includes one or more of nickel sulfate, nickel chloride, nickel nitrate and nickel acetate.

7. The preparation method according to claim 5, characterized in that: The modified dopant includes one or more of lithium carbonate, silver oxide, magnesium hydroxide, magnesium oxide, manganese carbonate, cobalt hydroxide, copper oxide, zinc oxide, titanium dioxide, vanadium pentoxide, iron nitrate, indium oxide, tin oxide, aluminum powder, calcium hydroxide, antimony oxide and barium carbonate.

8. The preparation method according to claim 5, characterized in that: When the nickel source and the modified dopant are mixed, a sintering aid is also added, and the sintering aid includes sodium bicarbonate and / or silicon dioxide.

9. The preparation method according to claim 5, characterized in that: The dispersant includes one or more of ethanol, oxalic acid, nitric acid, polyethylene glycol, sodium citrate, sodium pyrophosphate and sodium polyphosphate.

10. The preparation method according to claim 5, characterized in that: The binder includes one or more of vinyl acetate, polyvinyl alcohol, epoxy resin, epoxy acrylate and phenolic resin; the defoamer includes one or more of sodium phosphate, polyacrylate, sodium polyacrylate, hydroxymethyl cellulose and polyacrylamide.

Images