Method for preparing coating through pore plate assisted liquid self-spreading

Abstract

The invention belongs to the field of coating preparation, and particularly relates to a method for preparing a coating through pore plate auxiliary liquid self-spreading. The method for preparing the coating through the pore plate assisting liquid self-spreading comprises the steps that liquid is added to the pore plate with small holes, and when the liquid passes through the small holes, under the action of the surface tension of the liquid and the adhesive force between the hole walls and the liquid, the liquid horizontally diffuses on the pore plate and meanwhile penetrates through the small holes to leak to the surface of a printing stock; and then the liquid on the printing stock continues to be self-spread to form the film under the action of surface tension. The method is simple and convenient in process, simple in tool, easy to amplify and low in cost.

Description

Technical Field

[0001] The present invention relates to a method for preparing a coating by using an orifice plate to assist liquid self-spreading, and belongs to the field of coating preparation. Background Art

[0002] Liquid film formation has always been an important process in industry and is used in many industries, such as the photovoltaic industry, the panel industry, etc. At present, perovskite solar cells have broad application prospects in the photovoltaic industry. Each layer in perovskite solar cells uses the process of liquid film formation.

[0003] The film formation quality of the perovskite active layer, functional layer, and electrode layer determines the product performance and directly affects its carrier mobility, carrier lifetime, and photovoltaic conversion performance. In particular, the film formation quality of the perovskite active layer, and the importance of its manufacturing process can be imagined. And for a high-quality liquid film formation process, whether it is convenient for scale-up, industrialization, and its equipment cost are issues faced in the industry.

[0004] Currently, in perovskite solar cells, the mainstream liquid film formation methods include: spin coating, screen printing, slot die coating, and inkjet printing. Spin coating is not suitable for enlarging the cell area. When spin coating on a large area, the film formation is uneven between the middle and the periphery, and the amount of solution wasted is too large, and most of the solution is thrown away; although screen printing is convenient for scale-up and the equipment cost is not too high, it is only suitable for slurries with relatively high viscosity and is mostly used for the preparation of micron-scale thick films with a mesoporous structure, and is not suitable for the preparation of low-viscosity liquids and nano-scale thin films. Slot die coating and inkjet printing, although suitable for large-area production and low-viscosity liquids, have high precision requirements for the coating head or nozzle, and the manufacturing cost is expensive.

[0005] Patent Document 1 (Chinese Patent Publication No. CN111048667A) designed a coating process and device suitable for uniformly coating a perovskite active layer on a large-area substrate. Patent Document 2 (Chinese Patent Publication No. CN108922654A) developed a low-temperature screen-printable carbon paste and a highly conductive carbon electrode because its battery was prepared by a full screen printing process. Summary of the Invention

[0006] In view of the above problems, the technical problem to be solved by the present invention is to provide a method for preparing a coating by using an orifice plate to assist liquid self-spreading, which has a simple process, simple tooling and is easy to scale up, low cost, and is suitable for manufacturing perovskite solar cells.

[0007] Specifically, the present invention provides a method for preparing a coating by using an orifice plate to assist liquid self-spreading, which includes: adding a liquid onto an orifice plate with small holes; when the liquid passes through the small holes, under the action of the surface tension of the liquid and the adhesion force between the hole wall and the liquid, while horizontally diffusing on the orifice plate, it leaks through the small holes to the surface of the substrate; then the liquid on the substrate continues to self-spread into a film under the action of the surface tension.

[0008] In the present invention, by adding the liquid onto the orifice plate, when the liquid horizontally diffuses on the orifice plate, at this time, due to the gravity of the liquid being greater than the adhesion force between the liquid and the hole wall, the liquid that cannot be adsorbed in the hole passes through the hole and leaks onto the substrate. Then the liquid on the substrate continues to self-spread into a film under the action of the surface tension.

[0009] According to the present invention, when adding the liquid onto the orifice plate, under the action of the surface tension of the liquid and the adhesion force between the hole wall and the liquid, it spreads on the surface of the orifice plate with better wettability. Due to the gravity of the liquid being greater than the adhesion force between the liquid and the hole wall, the liquid that cannot be adsorbed in the hole continues to pass through the hole and leaks onto the substrate. It is necessary to ensure that: the surface tension, viscosity of the liquid are matched with the wettability of the hole wall and the pore diameter. If the surface tension of the liquid is too large, and / or the viscosity is too large, and / or the pore diameter is too small, a liquid film will be formed on the orifice plate and be adsorbed, unable to drip. Using this method, compared with the common methods, this method has simple process, simple tooling, easy to scale up, and low cost.

[0010] In the present invention, the surface tension, viscosity of the liquid and the wettability of the hole wall, pore diameter must be mutually matched; the condition for the liquid to leak is that: at the position of the hole, the vertical upward component of the adhesion force (F) between the hole wall and the liquid < the gravity (G) of the liquid itself; The calculation formula for the adhesion force between the hole wall and the liquid is: F = γL, where γ is the surface tension coefficient of the liquid; L is the contact perimeter between the liquid and the hole wall; The calculation formula for the liquid gravity is: G = mg.

[0011] Preferably, the liquid re-self-spreads into a film on the surface of the substrate, and the action of the surface tension can be the surface tension of the liquid itself, or the combined action of the surface tension of the liquid and the capillary force between the orifice plate, substrate and the liquid, and both are less than the critical surface tension of the substrate surface.

[0012] Preferably, the liquid adding method on the orifice plate can be at least one of: dropping, spraying, dipping, immersing, scraping, coating, spreading.

[0013] Preferably, if the liquid adding method is applied to industrial production, it can supply liquid quantitatively and at a fixed point through an automated device.

[0014] Preferably, the liquid is a liquid for preparing a perovskite solar cell; the liquid includes: an active layer ink, a functional layer ink, and an electrode layer ink.

[0015] Preferably, the chemical formula of the active substance in the active layer ink is ABX3; where A is a monovalent cation selected from + [CH(NH2)2] + [(CH2)3NH2] + [NH3OH] + [C3N2H5] + [(CH3CH2)NH3] + [(CH3)2NH2] + [(NH2)3C] + [(CH3)4N] + [C3H4NS] + [NC4H8] + [C7H7] + K + Rb + Cs + at least one of; B is Pb 2+ Sn 2 + Co 2+ Mn 2+ Ge 2+ Mg 2+ Ca 2+ Sr 2+ Ba 2+ Cu 2+ Fe 2+ Pd 2+ Eu 2+ Ni 2+ or Bi 3+ at least one of; X is F - Cl - Br - I - or SCN - at least one of; the solvent in the active layer ink is selected from at least one of dimethylformamide, N-methylformamide, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, N-methyl-2-pyrrolidone, methanol, isopropanol, ethylene glycol, water, ethyl acetate, triethyl phosphate, 2-methoxyethanol, cyclopentyl methyl ether, and N-hydroxymethylacrylamide; the concentration of the active layer ink is 0.5 to 2.0 mol / L.

[0016] Preferably, the functional layer ink contains at least one of a dense layer ink, an electron transport layer ink, an insulating layer ink, and a hole transport layer ink; the solvent of the functional layer ink is selected from at least one of water and organic solvents containing hydroxyl groups, ether bonds, thioethers, aldehyde groups, carboxyl groups, carbonyl groups, ester groups, carbocyclic compounds, and heterocyclic compounds; The dense layer material is selected from metal oxides, preferably at least one of titanium oxide and its dopants, tin oxide and its dopants, and zinc oxide and its dopants; The electron transport layer material is selected from at least one of titanium oxide and its dopants, tin oxide and its dopants, indium oxide and its dopants, zinc oxide and its dopants, cadmium sulfide and its dopants, zinc sulfide and its dopants, zinc selenide and its dopants, fullerenes and their derivatives, graphene and its derivatives, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, and tris(2,4,6-trimethyl-3-(pyridin-3-yl)phenyl)borane; The insulating layer material is selected from at least one of aluminum oxide, zirconium oxide, and magnesium oxide; The hole transport layer material is selected from at least one of nickel oxide, cuprous oxide, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid, carbazole substituted with phosphonic acid-functionalized dimethoxydiphenylamine, arylamino-cyano vinyl phosphonic acid, and 2,2',7,7'-tetra[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene.

[0017] Preferably, the mass percentage concentration of the functional layer ink ≤ 15%.

[0018] Preferably, the electrode layer ink includes at least one of graphite, carbon black, carbon nanotubes, carbon fibers, graphene, indium tin oxide, aluminum zinc oxide, indium zinc oxide, or fluorine-doped tin oxide; the solvent of the electrode layer ink is selected from at least one of water and organic solvents containing hydroxyl groups, ether bonds, thioethers, aldehyde groups, carboxyl groups, carbonyl groups, ester groups, carbocyclic compounds, and heterocyclic compounds; the mass percentage concentration of the electrode layer ink ≤ 15%.

[0019] Preferably, the surface tension coefficient of the liquid < 0.2 N / m.

[0020] Preferably, the material of the orifice plate includes one of stainless steel and polypropylene, and the contact angle with the liquid < 90 degrees; the pore diameter range of the orifice plate is 0.001 - 8 mm; the pore depth in the orifice plate is 0.001 - 8 mm.

[0021] Preferably, the holes of the orifice plate, in addition to being distributed vertically, also include a horizontal distribution (i.e., the liquid in the holes can flow horizontally in addition to flowing up and down).

[0022] Preferably, the distance between the orifice plate and the substrate to be printed is 0 to 5 mm and not 0.

[0023] In a second aspect, the present invention provides a coating prepared according to the above method.

[0024] In a third aspect, the present invention provides a perovskite solar cell, and the structure of the perovskite solar cell includes at least one of an active layer, a functional layer, and an electrode layer prepared according to the above method.

[0025] Preferably, the thickness of the active layer is 1 to 1000 nm; When the functional layer is a dense layer, the thickness is 1 to 100 nm; When the functional layer is an electron transport layer, the thickness is 2 to 2000 nm; When the functional layer is an insulating layer, the thickness is 2 to 4000 nm; When the functional layer is a hole transport layer, the thickness is 2 to 2×10 4 nm; The thickness of the electrode layer is 0.01 to 200 μm.

[0026] Preferably, when fabricating the dense layer, the preparation method includes: 1) Place the transparent conductive layer on the substrate upward on a horizontal platform; 2) Place the orifice plate above the transparent conductive layer and adjust the gap between the lower surface of the orifice plate and the upper surface of the transparent conductive layer; preferably, the orifice plate is an orifice plate made of stainless steel wire, and the pore diameter is 18 to 250 μm; 3) Add the dense layer ink in the middle of the orifice plate. The dense layer ink spreads on the orifice plate and leaks onto the transparent conductive layer. Lift the orifice plate away from the transparent conductive layer, and the dense layer ink will continue to self-spread on the transparent conductive layer to form a dense layer liquid film. 4) Perform heat annealing treatment on the dense layer liquid film to form a dense layer.

[0027] Preferably, the composition of the dense layer ink includes at least one of titanium oxide and its dopants, tin oxide and its dopants, zinc oxide and its dopants; the solvent includes at least one of water and an organic solvent containing hydroxyl, ether bond, thioether, aldehyde group, carboxyl group, carbonyl group, ester group, carbocyclic compound, and heterocyclic compound, and the mass percentage concentration ≤15%.

[0028] Advantages of the present invention: The present invention can provide a method for preparing a coating by orifice plate-assisted liquid self-spreading with simple process, simple tooling and easy to scale up, and low cost. According to the following specific embodiments and with reference to the drawings, the above content and other objects, features, and advantages of the present invention will be better understood. Description of the Drawings

[0029] Figure 1 It is a front view of a battery structure in a perovskite solar cell fabricated according to a hole plate-assisted liquid self-spreading process of the present invention; Figure 2 It is a front view of a battery that is only used to fabricate a perovskite active layer in another battery structure in a perovskite solar cell fabricated according to a hole plate-assisted liquid self-spreading process of the present invention; Figure 3 It is a side view of the self-spreading process of the dense layer in a perovskite solar cell fabricated according to a hole plate-assisted liquid self-spreading process of the present invention; Figure 4 It is a side view of the self-spreading and infiltration process of the perovskite active layer ink in a perovskite solar cell fabricated according to a hole plate-assisted liquid self-spreading process of the present invention; Figure 5 It is a comparison of the photoelectric conversion performance of photovoltaic cells fabricated by using the methods of Example 1, Example 2, Comparative Example 1, and Comparative Example 2 in a perovskite solar cell fabricated according to a hole plate-assisted liquid self-spreading process of the present invention; Figure 6 It is a comparison diagram of the photoelectric conversion performance of photovoltaic cells fabricated by using the methods of Example 3 and Comparative Example 3 (hole plate-assisted self-spreading process for infiltrating perovskite ink and drop-coating infiltration of perovskite ink) in a perovskite solar cell fabricated according to a hole plate-assisted liquid self-spreading process of the present invention; For the liquid, liquid film, and the layers formed thereby in the drawings, the same reference numerals are used, but different textual descriptions are used; The shapes and sizes of the liquid and the mesh holes in the drawings are only for convenience of distinction and are not limited thereto; The infiltration amount of the liquid in the drawings is only for convenience of distinction and is not limited thereto; The front and rear perspectives of the liquid and the mesh hole walls in the drawings are only for convenience of distinction and are not limited thereto; In each figure, the same or corresponding reference numerals represent the same component, and repeated descriptions are omitted. Reference numerals: 1. Substrate; 2. Transparent conductive layer; 3. Dense layer; 3a. Dense layer ink; 3b. Dense layer liquid film; 4. Electron transport layer; 5. Insulating layer; 6. Perovskite active layer; 6a. Perovskite ink; 6b. Perovskite liquid film; 7. Hole transport layer; 8. Top electrode layer; 9. Auxiliary electrode; 10. Insulating region; 101. Orifice plate; 101a. Hole. Detailed implementation manners

[0030] The present invention will be further described through the following implementation manners. It should be understood that the following implementation manners are only used to illustrate the present invention and do not limit the present invention.

[0031] In the present disclosure, when liquid is added to the orifice plate and spreads on the orifice plate, due to the gravity of the liquid being greater than the adhesion force between the liquid and the orifice wall. Therefore, the liquid that cannot be adsorbed in the hole passes through the hole and leaks onto the printing substrate. Then, the liquid on the printing substrate continues to spread into a film under the action of surface tension.

[0032] Moreover, in the present invention, the liquid can be a solution, a colloid, a suspension, etc.

[0033] Moreover, in the present invention, it can also be that the wettability of the printing substrate and the surface tension of the liquid match each other to ensure that the liquid leaking onto the printing substrate can continue to spread into a film.

[0034] Moreover, in the present invention, it can also be that the surface tension under which the liquid re-self-spreads into a film on the surface of the printing substrate can be the surface tension of the liquid itself, or the combined action of the surface tension of the liquid and the capillary force between the orifice plate, the printing substrate and the liquid to form a liquid film.

[0035] Moreover, in the present invention, it can also be that the orifice plate is provided with holes through which the liquid can leak, and the liquid discharge amount is controlled by controlling its parameters: mesh number, pore diameter, orifice plate thickness, the gap between the orifice plate and the surface of the printing substrate, and the orifice wall material. Preferably, the holes of the orifice plate include not only vertical distribution but also horizontal distribution (that is, the liquid in the hole can not only flow up and down but also diffuse laterally).

[0036] Moreover, in the present invention, it can also be that the preferred parameters of the orifice plate are: mesh number range: 80 - 730 meshes, pore diameter range: 20 - 300 microns, orifice plate thickness range: 30 - 300 microns, the gap between the orifice plate and the surface of the printing substrate range: 0 - 5 mm and not 0, and the orifice wall material is metal or polymer material.

[0037] Also, in the present invention, it can also be that the material of the orifice plate needs to match the self-spreading liquid, and the wettability between different materials of the orifice plate and different liquids is different. In addition, perovskite inks mostly use solvents with relatively strong polarity. Preferably, the orifice plate used in this step needs to select a material with better solvent resistance, which can be stainless steel, tungsten, polypropylene, polytetrafluoroethylene, or silicone resin. Also, in the present invention, it can also be that the orifice plate can be a common screen printing stencil.

[0038] Also, in the present invention, it can also be that for the liquid, the volatility of the solvent needs to be regulated. This ensures that in large-scale production, the orifice will not be blocked due to the liquid drying in the orifice. Therefore, a solvent with low volatility is preferably selected.

[0039] Also, in the present invention, it can also be that the surface tension of the liquid can be increased by adding non-surface-active substances, such as inorganic salts, non-volatile acids, and bases, or decreased by adding surface-active substances, such as short-chain fatty acids, alcohols, and aldehydes.

[0040] Also, in the present invention, it can also be that if the contact angle between the liquid and the substrate is too large (the wettability between the liquid and the substrate is poor), the wettability of the liquid on the surface of the substrate can be improved by ultraviolet treatment and / or plasma treatment.

[0041] Also, in the present invention, it can also be that the perovskite solar cell includes several or all of a dense layer, an electron transport layer, an insulating layer, a perovskite active layer, a hole transport layer, and a top electrode layer.

[0042] A process for assisting the self-spreading of a liquid with an orifice plate, when used for fabricating a perovskite solar cell, includes fabricating a certain layer, several layers, or all of the active layers, functional layers, and electrode layers in the perovskite solar cell.

[0043] A process for assisting the self-spreading of a liquid with an orifice plate, when used for fabricating the dense layer in a perovskite solar cell, includes: 1) Place the transparent conductive layer on the substrate upward on a horizontal platform; 2) Use a stainless steel wire to make an orifice plate. Place the orifice plate above the transparent conductive layer and adjust the gap between the lower surface of the orifice plate and the upper surface of the transparent conductive layer; 3) Add a certain amount of dense layer ink in the middle of the orifice plate. The dense layer ink spreads on the orifice plate and leaks down to the transparent conductive layer. Lift the orifice plate away from the transparent conductive layer, and the dense layer ink will continue to self-spread on the transparent conductive layer to form a dense layer liquid film; 4) Heat and anneal the dense layer liquid film to form a dense layer.

[0044] In a more preferred embodiment, the doping elements in the titanium oxide dopant include at least one of alkali (earth) metal elements, non-metal elements, and elements with transition metal properties, and the total doping content does not exceed 10 mol%. Among them, the alkali (earth) metal elements include lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, etc. The non-metal elements include nitrogen, carbon, sulfur, fluorine, chlorine, bromine, iodine, boron, phosphorus, silicon, etc. The elements with transition metal properties include iron, cobalt, nickel, manganese, copper, zinc, cadmium, niobium, tantalum, aluminum, gallium, germanium, antimony, bismuth, indium, tin, vanadium, chromium, molybdenum, silver, platinum, etc.

[0045] In a more preferred embodiment, the doping elements in the tin oxide dopant include at least one of alkali (earth) metal elements, non-metal elements, and elements with transition metal properties, and the total doping content does not exceed 10 mol%. Among them, the alkali (earth) metal elements include lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, etc. The non-metal elements include nitrogen, carbon, sulfur, fluorine, chlorine, bromine, iodine, boron, phosphorus, silicon, etc. The elements with transition metal properties include titanium, iron, cobalt, nickel, manganese, copper, zinc, cadmium, niobium, tantalum, aluminum, gallium, germanium, antimony, bismuth, indium, vanadium, chromium, molybdenum, silver, platinum, etc.

[0046] In a more preferred embodiment, the doping elements in the indium oxide dopant include at least one of alkali (earth) metal elements, non-metal elements, and elements with transition metal properties, and the total doping content does not exceed 10 mol%. Among them, the alkali (earth) metal elements include lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, etc. The non-metal elements include nitrogen, carbon, sulfur, fluorine, chlorine, bromine, iodine, boron, phosphorus, silicon, etc. The elements with transition metal properties include titanium, iron, cobalt, nickel, manganese, copper, zinc, cadmium, niobium, tantalum, aluminum, gallium, germanium, antimony, bismuth, tin, vanadium, chromium, molybdenum, silver, platinum, etc.

[0047] In a more preferred embodiment, the doping elements in the zinc oxide dopant include at least one of alkali (earth) metal elements, non-metal elements, and elements with transition metal properties, and the total doping content does not exceed 10 mol%. Among them, the alkali (earth) metal elements include lithium, sodium, potassium, rubidium, cesium, magnesium, calcium, strontium, barium, etc. The non-metal elements include nitrogen, carbon, sulfur, fluorine, chlorine, bromine, iodine, boron, phosphorus, silicon, etc. The elements with transition metal properties include titanium, iron, cobalt, nickel, manganese, copper, cadmium, niobium, tantalum, aluminum, gallium, germanium, antimony, bismuth, indium, tin, vanadium, chromium, molybdenum, silver, platinum, etc.

[0048] In a more preferred embodiment, the doping elements in the cadmium sulfide dopant include at least one of zinc, magnesium, calcium, strontium, barium, copper, silver, barium, gallium, thallium, aluminum, cobalt, nickel, manganese, germanium, tin, silicon, selenium, tellurium, and the total doping content does not exceed 10 mol%.

[0049] In a more preferred embodiment, the doping elements in the zinc sulfide dopant include at least one of cadmium, magnesium, calcium, strontium, barium, copper, silver, barium, gallium, thallium, aluminum, cobalt, nickel, manganese, germanium, tin, silicon, selenium, tellurium, and the total doping content does not exceed 10 mol%.

[0050] In a more preferred embodiment, the doping elements in the zinc selenide dopant include at least one of cadmium, magnesium, calcium, strontium, barium, copper, silver, barium, gallium, thallium, aluminum, cobalt, nickel, manganese, germanium, tin, silicon, sulfur, tellurium, and the total doping content does not exceed 10 mol%.

[0051] In a more preferred embodiment, the fullerene derivatives include: [6,6]-phenyl-carbon 61-butyrate methyl ester, [6,6]-phenyl-carbon 71-butyrate methyl ester, fullero pyrrolidine, etc.

[0052] In a more preferred embodiment, the graphene derivatives include: graphene chloride, graphene fluoride, graphene oxide, reduced graphene oxide, carboxylated graphene, aminated graphene, nitrogen-doped graphene, phosphorus-doped graphene, sulfur-doped graphene, boron-doped graphene, etc.

[0053] Figure 1 It is a front view of a perovskite solar cell fabricated by the orifice plate-assisted liquid self-spreading process according to an embodiment of the present invention, showing one kind of battery structure. Figure 2 It is a front view of a perovskite solar cell fabricated by the orifice plate-assisted liquid self-spreading process according to an embodiment of the present invention, showing another kind of battery structure, which is only used for fabricating the perovskite active layer. Figure 3 It is a perovskite solar cell fabricated by a kind of orifice plate-assisted liquid self-spreading process according to the present invention. Figure 1 In the battery with this structure, it is a side view of the self-spreading process of the dense layer ink. Figure 4 It is a perovskite solar cell fabricated by a kind of orifice plate-assisted liquid self-spreading process according to the present invention. Figure 2 In the battery with this structure, it is a side view of the self-spreading and penetration process of the perovskite ink. Figure 5 It is a comparison of the photovoltaic conversion performance of photovoltaic cells fabricated by using the methods of Example 1, Example 2, Comparative Example 1, and Comparative Example 2. Figure 6 It is a comparison of the photovoltaic conversion performance of photovoltaic cells fabricated by using the methods of Example 3 and Comparative Example 3. To solve the above technical problems, the present invention provides a method for preparing a coating by orifice plate-assisted liquid self-spreading, which has the advantages of simple process, simple tooling, easy scale-up, and low cost.

[0054] Moreover, as will be described in detail in this embodiment and the following embodiments, as Figure 1As shown in the figure: An insulating region 10 for distinguishing the positive and negative electrodes of the battery is fabricated on the transparent conductive layer 2 on the substrate 1, making the transparent conductive layer 2 discontinuous; a dense layer 3 is fabricated on the transparent conductive layer 2, with the position of the dense layer 3 being to the left of the insulating region 10. Using the same process, an electron transport layer 4, a perovskite active layer 6, a hole transport layer 7, and a top electrode layer 8 are successively fabricated on the dense layer 3. The sizes of the layers 3 to 7 are exactly the same. While the left side of the top electrode layer 8 is aligned with the layers below, the right side crosses the insulating region 10 and contacts the transparent conductive layer 2 on the right side of the insulating region 10. Finally, tin-plated copper tapes are respectively pasted on the outermost two sides of the transparent conductive layer 2 as auxiliary electrode layers 6, serving as the positive and negative electrodes of the battery. Finally, a perovskite solar cell is fabricated.

[0055] As Figure 3 shown, the dense layer ink 3a to be infiltrated is dropped onto the hole 101a of the orifice plate 101. Due to the combined action of surface tension and the adhesion force between the hole wall and the ink, the ink 3a spreads on the surface of the hole 101a. Since the vertical upward component of the adhesion force between the ink 3a and the wall of the hole 101a is less than the gravity of the ink 3a, the ink 3a cannot be adsorbed in the hole 101a, and the ink 3a continues to pass through the hole 101a and leaks onto the surface of the substrate (the transparent conductive layer 2 fabricated on the substrate 1 in this figure); then the ink 3a on the substrate continues to spread into a liquid film 3b under the action of surface tension. The size of the orifice plate 101 and its relative position to the transparent conductive layer 2 need to be controlled during this process.

[0056] As Figure 4 shown, on the semi-finished battery with each layer prefabricated (the transparent conductive layer 2, the dense layer 3b, the electron transport layer 4, the insulating layer 5, the hole transport layer 7, and the top electrode layer 8 are successively fabricated on the substrate 1), the perovskite active layer 6 is prepared using the orifice plate-assisted liquid self-spreading process. The perovskite ink 6a to be infiltrated is added onto the hole 101a of the orifice plate 101. The perovskite ink 6a spreads on the surface of the hole 101a and continues to pass through the hole 101a and leaks onto the surface of the substrate (the semi-finished battery); then, under the action of its own gravity and the capillary force of the top electrode layer 8, it penetrates downward. Finally, an appropriate amount of perovskite ink 6a fills the electron transport layer 4 and is annealed to form the perovskite active layer 6. Finally, a Figure 2 perovskite solar cell with the structure shown is fabricated.

[0057] The following examples are further cited to illustrate the present invention in detail. It should also be understood that the following examples are only used to further illustrate the present invention and cannot be interpreted as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the scope of protection of the present invention. The specific process parameters and the like in the following examples are only examples within a suitable range, that is, those skilled in the art can make selections within a suitable range through the description herein, and are not limited to the specific numerical values exemplified below. The meaning of solid content in the following examples and comparative examples is mass percentage concentration.

[0058] Comparative Example 1: Preparation of perovskite solar cells 1) Laser etching is used to create an insulating area, making the transparent conductive layer discontinuous. The two sides of the insulating area serve as the positive and negative electrodes of the battery respectively. 2) ultrasonically cleaning the surface of the transparent conductive layer on the substrate with acetone, alkaline detergent, deionized water, and acetone for 15 minutes respectively, and finally drying it; 3) Screen-printing a dense titanium oxide layer onto the transparent conductive layer. The screen mesh was 400 mesh (pore size 38 μm), the scraper speed was 60 mm / s, and the pressing pressure was 0.28 MPa. The dense titanium oxide layer slurry consisted of the following ingredients: 1.5 ml of tetraisopropyl titanate, 3.5 g of ethyl cellulose, and 80 ml of terpineol. The slurry was then sintered in a muffle furnace at 510°C for 30 minutes. 4) Screen-printing a titanium oxide electron transport layer on the dense layer. The screen mesh size was 325 (pore size 45 μm), the scraper speed was 50 mm / s, and the pressing pressure was 0.25 MPa. The titanium oxide electron transport layer slurry, containing nano-titanium dioxide as the solute, ethyl cellulose as the binder, and terpineol as the solvent, had a solid content (mass fraction) of 10%, and was sintered in a muffle furnace at 510°C for 30 minutes. 5) 461 mg of lead iodide (PbI2) powder, 159 mg of methylamine iodide (CH3NH3I) powder, and 78 mg of dimethyl sulfoxide (DMSO) were mixed in 600 mg of N,N-dimethylformamide (DMF) and stirred at room temperature for 1 hour to form methylamine lead iodide (CH3NH3PbI3) perovskite ink (concentration of 0.478 mol / L); 6) Using this ink as a spin coating solution, prepare a perovskite active layer on the electron transport layer by spin coating. Add 80 μL of the perovskite ink dropwise and spin coat at 5000 rpm for 20 seconds. 7) Annealing at 120 degrees Celsius for 10 minutes to form a perovskite active layer; 8) On the perovskite active layer, a hole transport layer of 2,2',7,7'-tetrakis[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD) was spin-coated. Its composition is: 72.3 mg of Spiro-OMeTAD, 1 mL of chlorobenzene, 28.8 μL of 4-tert-butylpyridine (TBP), 17.5 μL of lithium bis(trifluoromethanesulfonyl)imide (Li-TFSI), and 29 μL of cobalt(III) bis(trifluoromethanesulfonyl)imide salt (FK209). The rotation speed was 4000 revolutions per minute for 20 seconds; 9) By thermal evaporation, a 100-nm-thick silver electrode was deposited on the hole transport layer; 10) On the transparent conductive layer, at the edges on both sides of the cell, tin-plated copper tape was pasted as an auxiliary electrode to fabricate a perovskite solar cell.

[0059] Comparative Example 2 used the full screen printing method to fabricate a perovskite solar cell: 1) 1) - 4) The fabrication method was the same as that of Comparative Example 1; 2) Weighed 2.88 g of lead iodide (PbI2) powder and 975 mg of methylammonium iodide (CH3NH3I) powder and dissolved them in 5 mL of methylammonium acetate (MAAC) ionic liquid. It was continuously stirred in a nitrogen atmosphere at 60 °C for 12 hours to form a methylammonium lead iodide (CH3NH3PbI3) perovskite slurry; 3) The intermediate product of the perovskite solar cell was placed on a horizontal platform with the electron transport layer facing up; 4) A stainless steel wire was used to make a wire mesh with a mesh size of 325 mesh (pore diameter of 45 μm). The wire mesh was placed above the intermediate product of the perovskite solar cell, and the gap between the lower surface of the wire mesh and the upper surface of the electron transport layer was adjusted to 3 mm; 5) 2 mL of the perovskite slurry was poured onto the non-porous area on one side of the wire mesh. A 50-mm-long silicone scraper was used to directly contact the wire mesh, and a pressure of 0.3 MPa was applied downward above it. The scraper was uniformly moved from the non-porous area on one side of the wire mesh to the non-porous area on the other side of the wire mesh. The moving speed was 30 mm / s, and the angle between the scraper and the wire mesh was 60 degrees. When passing through the pore area, due to the extrusion of the scraper, the perovskite slurry was extruded from the wire mesh pores onto the titanium oxide electron transport layer. During this process, the scraper, the slurry, the wire mesh, and the titanium oxide electron transport layer were in linear direct contact; 6) The active layer liquid film was annealed on a hot plate at 120 °C for 10 minutes to form a crystalline perovskite active layer; 7) 8) - 10) The fabrication method was the same as that of Comparative Example 1.

[0060] Example 1 used the method of the present invention to fabricate the titanium oxide dense layer in the perovskite solar cell: 1) 1) - 2) The manufacturing method is the same as that of Comparative Example 1; 2) Place the transparent conductive layer on the substrate facing upwards on a horizontal platform; 3) Use a stainless - steel wire to make a perforated plate. The size of the middle hole area is 20 mm × 10 mm, the mesh number of the perforated plate is 500 mesh (pore diameter is 25 μm), and the pore depth is 67 μm. Place the perforated plate above the transparent conductive layer and adjust the gap between the lower surface of the perforated plate and the upper surface of the transparent conductive layer to 0.1 mm; 4) Add 5 μL of titanium dioxide dense layer ink (composition: 0.3 mol / L titanium tetraisopropoxide, 0.45 mol / L acetylacetone, 0.09 mol / L hydrochloric acid, 1.8 mol / L water, and the solvent is ethanol) to the middle hole area. The ink spreads on the surface and inside of the holes and leaks onto the transparent conductive layer. Lift the perforated plate away from the transparent conductive layer, and the titanium dioxide dense layer ink will continue to self - spread on the transparent conductive layer to form a dense layer liquid film, and sinter it in a muffle furnace at 510 °C for 30 minutes; 5) 4) - 10) The manufacturing method is the same as that of Comparative Example 1.

[0061] Example 2 manufactures the entire perovskite solar cell using the method of the present invention: 1) 1) - 4) The manufacturing method is the same as that of Example 1; 2) Using the same perforated plate process parameters as in Example 1, fabricate a titanium dioxide electron transport layer on the titanium dioxide dense layer. The titanium dioxide electron transport layer ink (the solute is nano - titanium dioxide, the solvent is ethanol; the concentration is 40 mmol / L), the dropping amount is 10 μL, self - spread to form a liquid film, and then sinter it in a muffle furnace at 510 °C for 30 minutes; 3) Using the same perforated plate process parameters as in Example 1, fabricate a perovskite active layer on the titanium dioxide electron transport layer. The perovskite ink is fabricated in the same way as in Comparative Example 1. The dropping amount is 10 μL, self - spread to form a liquid film, then perform vacuum crystallization treatment for 5 minutes, and then anneal at 100 °C for 5 minutes to form a perovskite active layer; 4) Using the same perforated plate process parameters as in Example 1, fabricate a Spiro - OMeTAD hole transport layer on the perovskite active layer. The Spiro hole transport layer ink formulation is the same as in Comparative Example 1 (the ink concentration is 0.037 mol / L), the dropping amount is 5 μL, self - spread, and let it stand to form a film; 5) Using the same perforated plate process parameters as in Example 1, fabricate a carbon top electrode layer on the Spiro - OMeTAD hole transport layer. The solid content (mass fraction) of the carbon chlorobenzene dispersion is 20%, the dropping amount is 20 μL, self - spread to form a liquid film, and then perform vacuum treatment at room temperature for 10 minutes; 6) On the transparent conductive layer, at both edges of the battery, paste tin - plated copper tape as an electrode collector strip to fabricate a perovskite solar cell.

[0062] Preparation of perovskite active layer and its battery by drop coating method in Comparative Example 3: 1) The manufacturing methods of 1) - 4) are the same as those in Comparative Example 1; 2) On the titanium oxide electron transport layer, screen-print (screen mesh count is 325 meshes (pore diameter is 45 microns), squeegee speed is 50 mm / s, downward pressure is 0.25 MPa) zirconia slurry (solid content (mass fraction) is 12%, binder is ethyl cellulose, solvent is terpineol) as the insulating layer, and sinter in a muffle furnace at 510 °C for 30 minutes; 3) On the zirconia insulating layer, screen-print (screen mesh count is 325 meshes (pore diameter is 45 microns), squeegee speed is 50 mm / s, downward pressure is 0.25 MPa) nickel oxide slurry (solid content (mass fraction) is 10%, binder is ethyl cellulose, solvent is terpineol) as the hole transport layer, and sinter in a muffle furnace at 510 °C for 30 minutes; 4) On the nickel oxide hole transport layer, screen-print (screen mesh count is 165 meshes (pore diameter is about 93 microns), squeegee speed is 30 mm / s, downward pressure is 0.3 MPa) carbon slurry (solid content (mass fraction) is 37%, binder is ethyl cellulose, solvent is terpineol) as the top electrode layer, and sinter in a muffle furnace at 430 °C for 30 minutes; 5) On the transparent conductive layer, at both edges of the battery, stick tin-plated copper tape as the electrode collecting strip; 6) Weigh 15.3 mg of 5-aminovaleric acid hydroiodide (5-AVAI), 576 mg of lead iodide (PbI2), and 195 mg of methylammonium iodide (CH3NH3I) powder. Measure 1 ml (the volume ratio of γ-butyrolactone (GBL) to ethanol is 4:1), and stir at 60 °C for 6 hours to form CH3NH3PbI3 perovskite ink (concentration is 1.25 mol / L, surface tension coefficient is 32.78 mN / m); 7) Drop 15 μl of perovskite ink onto the top electrode layer. Under the capillary force of the ink on the top electrode layer, it penetrates downward into the titanium oxide electron transport layer, stands still for 5 minutes, waits for it to fully penetrate, and anneals at 50 °C for 2 hours to fabricate a perovskite solar cell.

[0063] Example 3 Fabrication of the active layer of a mesoscopic perovskite solar cell using the method of the present invention: 1) The manufacturing methods of 1) - 6) are the same as those in Comparative Example 3; 2) Use a PET wire to make a perforated plate. The middle hole area is 15 mm × 15 mm, and the screen mesh count of the perforated plate is 325 meshes (pore diameter is 45 microns). Place the perforated plate on the top electrode layer and adjust the gap to 0.1 mm; 3) Add 15 μL of perovskite ink to the middle hole area. The ink spreads on the surface and inside of the hole and, under the capillary force of the top electrode layer, penetrates downward into the titanium oxide electron transport layer. Let it stand for 5 minutes to fully penetrate, and then anneal at 50 °C for 2 hours to fabricate a perovskite solar cell.

[0064] Comparative Example 4 The preparation process of the perovskite solar cell in this Comparative Example 4 refers to Example 1, with the only difference being that a hole plate made of stainless steel wire is used, the size of the middle hole area is 20 mm × 10 mm, and the mesh number of the hole plate is 200 meshes (pore diameter is 75 μm). The spreading area of the ink on the transparent conductive layer is small, and it is the same as the ink in Example 1. Due to the too large holes, the gravity of the ink in the same holes is too large, resulting in all of it leaking down before it can be spread out in time, unable to reach the designed size, and the film thickness is too thick to fabricate a battery.

[0065] Comparative Example 5 The preparation process of the perovskite solar cell in this Comparative Example 5 refers to Example 1, with the only difference being that a hole plate made of stainless steel wire is used, the size of the middle hole area is 20 mm × 10 mm, and the mesh number of the hole plate is 1000 meshes (pore diameter is 13 μm). The ink self-spreads and unfolds on the surface and inside of the mesh holes, but without external force, it cannot leak down.

[0066] Comparative Example 6 The preparation process of the perovskite solar cell in this Comparative Example 6 refers to Example 1, with the only difference being that a hole plate made of stainless steel wire is used, the size of the middle hole area is 20 mm × 1 mm, and the mesh number of the hole plate is 500 meshes (pore diameter is 25 μm). The hole plate is placed above the transparent conductive layer, and the gap between the lower surface of the hole plate and the upper surface of the transparent conductive layer is adjusted to 1 mm. Part of the ink diffuses on the transparent conductive layer under the action of surface tension, and the other part of the ink directly falls on the transparent conductive layer, resulting in uneven film thickness and unable to fabricate a battery. Because the gap is increased, there is more kinetic energy.

[0067] Comparative Example 7 The preparation process of the perovskite solar cell in this Comparative Example 7 refers to Example 1, with the only difference being that a hole plate made of stainless steel wire is used, the size of the middle hole area is 20 mm × 10 mm, and the mesh number of the hole plate is 500 meshes (pore diameter is 25 μm). The hole plate is placed above the transparent conductive layer, and the gap between the lower surface of the hole plate and the upper surface of the transparent conductive layer is adjusted to 2 mm. Most of the ink directly drips onto the transparent conductive layer, forming a coffee ring, and the film thickness is extremely uneven, unable to fabricate a battery (the principle is the same as in Example 6, with greater kinetic energy).

[0068] Comparative Example 8 Fabricate the titanium oxide compact layer in the perovskite solar cell using the method of the present invention: 1) 1) - 2) The manufacturing method is the same as that of Comparative Example 1; a dense layer with the same formulation as that of Comparative Example 1 is used. 2) Place the transparent conductive layer on the substrate face-up on a horizontal platform. 3) Use a stainless steel wire to make a perforated plate. The size of the middle hole area is 20 mm × 10 mm, and the mesh number of the perforated plate is 500 mesh (the pore diameter is 25 μm). Place the perforated plate above the transparent conductive layer and adjust the gap between the lower surface of the perforated plate and the upper surface of the transparent conductive layer to 0.1 mm. 4) Pour 2 ml of the titanium oxide dense layer slurry onto the middle hole area. The slurry cannot spread on the pore surface and cannot leak down. The slurry used in Comparative Example 1 has a high viscosity (about 5 Pa·s). At this time, due to the effect of viscosity, the slurry stays on the mesh surface.

[0069] Comparative Example 9 Use the method of the present invention to fabricate the titanium oxide dense layer in a perovskite solar cell: 1) 1) - 2) The manufacturing method is the same as that of Comparative Example 1; dilute the dense layer slurry in Comparative Example 1 by 5 times with ethanol. 2) Place the transparent conductive layer on the substrate face-up on a horizontal platform. 3) Use a stainless steel wire to make a perforated plate. The size of the middle hole area is 20 mm × 10 mm, and the mesh number of the perforated plate is 500 mesh (the pore diameter is 25 μm). Place the perforated plate above the transparent conductive layer and adjust the gap between the lower surface of the perforated plate and the upper surface of the transparent conductive layer to 0.1 mm. 4) Add 5 μl of the titanium oxide dense layer ink to the middle hole area. The ink spreads on the pore surface and inside and is adsorbed in the pores, but does not leak down without external force.

[0070] Table 1 shows the comparison of specific parameters between the examples and the comparative examples:

[0071] The above specific embodiments further elaborate on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above is only one specific embodiment of the present invention and is not limited to the protection scope of the present invention. Without departing from the gist of the basic features of the present invention, the present invention can be embodied in various forms. Therefore, the embodiments in the present invention are used to illustrate the present invention rather than limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for preparing a coating by using an orifice plate to assist liquid self-spreading, characterized in that, Including: Adding a liquid onto an orifice plate with small holes. When the liquid passes through the small holes, under the action of the surface tension of the liquid and the adhesion force between the hole wall and the liquid, while horizontally spreading on the orifice plate, it leaks through the small holes onto the surface of the substrate; then the liquid on the substrate continues to self-spread into a film under the action of the surface tension.

2. The method according to claim 1, wherein The surface tension, viscosity of the liquid, the wettability of the hole wall, and the pore diameter must match each other; the conditions that the liquid needs to meet when leaking are: at the position of the hole, the vertical upward component of the adhesion force (F) between the hole wall and the liquid < the gravity (G) of the liquid itself; The calculation formula for the adhesion force between the hole wall and the liquid is: F = γL, where γ is the surface tension coefficient of the liquid; L is the contact perimeter between the liquid and the hole wall; The calculation formula for the liquid gravity is: G = mg.

3. The method according to claim 1, characterized in that The action of the surface tension of the liquid on the substrate is the surface tension of the liquid itself, or the combined action of the surface tension of the liquid and the capillary force between the orifice plate, the substrate and the liquid, and < the critical surface tension of the substrate surface.

4. The method according to claim 1, characterized in that When the liquid is a liquid for preparing a perovskite solar cell, the liquid includes: active layer ink, functional layer ink, and electrode layer ink.

5. The method according to claim 4, characterized in that, The chemical formula of the active substance in the active layer ink is ABX3; where A is a monovalent cation selected from [[CH(NH2)2]] + , [[NH3NH2]] + , [[(CH2)3NH2]] + , [[NH3OH]] + , [[C3N2H5]] + , [[(CH3CH2)NH3]] + , [[(CH3)2NH2]] + , [[(NH2)3C]] + , [[(CH3)4N]] + , [[C3H4NS]] + , [[NC4H8]] + , [[C7H7]] + , K + , Rb + , Cs + ; B is Pb 2+ , Sn 2+ , Co 2+ , Mn 2+ , Ge 2+ , Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , Cu 2+ , Fe 2+ , Pd 2+ , Eu 2+ , Ni 2+ or Bi 3+ ; X is F - , Cl - , Br - , I - or SCN - ; The solvent in the active layer ink is selected from at least one of dimethylformamide, N-methylformamide, dimethyl sulfoxide, γ-butyrolactone, γ-valerolactone, N-methyl-2-pyrrolidone, methanol, isopropanol, ethylene glycol, water, ethyl acetate, triethyl phosphate, 2-methoxyethanol, cyclopentyl methyl ether, and N-hydroxymethylacrylamide; The concentration of the active layer ink is 0.5 - 2.0 mol / L.

6. The method according to claim 4, wherein The functional layer ink contains at least one of a dense layer material, an electron transport layer material, an insulating layer material, and a hole transport layer material; the solvent of the functional layer ink is selected from at least one of water and organic solvents containing hydroxyl groups, ether bonds, thioethers, aldehyde groups, carboxyl groups, carbonyl groups, ester groups, carbocyclic compounds, and heterocyclic compounds; The dense layer material is selected from metal oxides, preferably at least one of titanium oxide and its dopants, tin oxide and its dopants, and zinc oxide and its dopants; The electron transport layer material is selected from at least one of titanium oxide and its dopants, tin oxide and its dopants, indium oxide and its dopants, zinc oxide and its dopants, cadmium sulfide and its dopants, zinc sulfide and its dopants, zinc selenide and its dopants, fullerenes and their derivatives, graphene and its derivatives, 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, and tris(2,4,6-trimethyl-3-(pyridin-3-yl)phenyl)borane; The insulating layer material is selected from at least one of aluminum oxide, zirconium oxide, and magnesium oxide; The hole transport layer material is selected from at least one of nickel oxide, cuprous oxide, poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine], [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid, carbazole substituted with phosphonic acid-functionalized dimethoxydiphenylamine (V1036), arylamino-cyano vinyl phosphonic acid, and 2,2',7,7'-tetra[N,N-bis(4-methoxyphenyl)amino]-9,9'-spirobifluorene; The mass percentage concentration of the functional layer ink ≤ 15%.

7. The method according to claim 4, wherein The electrode layer ink includes at least one of graphite, carbon black, carbon nanotubes, carbon fibers, graphene, indium tin oxide, aluminum zinc oxide, indium zinc oxide, or fluorine-doped tin oxide; the solvent of the electrode layer ink is selected from at least one of water and organic solvents containing hydroxyl, ether bond, thioether, aldehyde group, carboxyl group, carbonyl group, ester group, carbocyclic compound, and heterocyclic compound; the mass percentage concentration of the electrode layer ink ≤ 15%.

8. The method according to any one of claims 4 to 7, characterized in that The surface tension coefficient of the liquid < 0.2 N / m.

9. The method according to any one of claims 1-8, wherein the material of the orifice plate comprises: At least one of a metal material, an inorganic non-metallic material, and a polymer material, with a contact angle with the liquid < 90 degrees; the pore diameter range of the orifice plate is 0.001 - 8 mm; the pore depth in the orifice plate is 0.001 - 8 mm.

10. The method according to any one of claims 1-9, characterized in that, The distance between the orifice plate and the substrate is 0 - 5 mm and not 0.

11. A coating prepared by the method according to any one of claims 1 - 10.

12. A perovskite solar cell, characterized in that, The structure of the perovskite solar cell comprises: At least one of an active layer, a functional layer, and an electrode layer prepared by the method according to claims 1 - 4.

13. The perovskite solar cell according to claim 12, characterized in that, The thickness of the active layer is 1 - 1000 nm; When the functional layer is a dense layer, the thickness is 1 - 100 nm; When the functional layer is an electron transport layer, the thickness is 2 - 2000 nm; When the functional layer is an insulating layer, the thickness is 2 - 4000 nm; When the functional layer is a hole transport layer, the thickness is 2 to 2×10 4 nanometers; The thickness of the electrode layer is 0.01 - 200 μm.

14. The perovskite solar cell according to claim 12, wherein When fabricating the dense layer, the preparation method includes: 1) Place the transparent conductive layer on the substrate upward on a horizontal platform; 2) Place the orifice plate above the transparent conductive layer and adjust the gap between the lower surface of the orifice plate and the upper surface of the transparent conductive layer; preferably, the orifice plate is an orifice plate made of stainless steel wire with a pore diameter of 18 - 250 μm; 3) Drop the dense layer ink in the middle of the orifice plate. The dense layer ink spreads on the orifice plate and leaks down to the transparent conductive layer. Lift the orifice plate away from the transparent conductive layer, and the dense layer ink will continue to self-spread on the transparent conductive layer to form a dense layer liquid film; 4) Perform heat annealing treatment on the dense layer liquid film to form a dense layer.

Images