Coating method, inkjet head, and coating device

Abstract

This is a coating method for ejecting a solution containing a perovskite solar cell material and a solvent from the nozzles of an inkjet head, and the solvent uses an aprotic polar solvent with a relative dielectric constant of 30 or more. The inkjet head has a diaphragm (32), a pressure chamber (311) whose volume expands or contracts with the movement of the diaphragm (32), a flow path (312) that supplies the solution to the pressure chamber (311), and an elastic member (20) that faces the flow path (312) and is arranged opposite the diaphragm (32). The drive signal used is a drive signal that includes one or more drive signal waveform elements that apply an expansion pulse and a contraction pulse consecutively in this order.

Description

[Technical Field]

[0001] The present invention relates to a coating method, an inkjet head, and a coating device. [Background technology]

[0002] In recent years, the development of solar cells with a perovskite compound in the power generation layer (hereinafter referred to as "perovskite solar cells") has progressed. Perovskite solar cells have attracted attention because, structurally, they do not require the thickness required for silicon crystalline solar cells, they are easy to fabricate as thin films, and they can be fabricated by solution coating, which allows for low cost.

[0003] A power generation layer containing a perovskite compound has conventionally been produced by a spin coating method (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2024-75070 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional coating methods such as spin coating are difficult to apply to large areas and are not suitable for high-throughput, scalable module manufacturing. Therefore, inkjet coating methods that enable large areas are desirable.

[0006] However, according to the investigations of the present inventors, there are problems in that solvents commonly used in inkjet inks are unable to dissolve perovskite compounds or their precursors at high concentrations, or even if they are able to dissolve them, the viscosity is too high to be suitable for inkjet printing. As a result, there are problems in that droplets cannot be ejected or the ejection trajectory is deviated, making it impossible to eject droplets stably.

[0007] The present invention has been made in view of the above circumstances, and has an object to provide a solution application method that can apply a solution containing a perovskite compound or a precursor thereof by an inkjet method and that can suppress ejection defects, as well as an inkjet head and application device used therein. [Means for solving the problem]

[0008] The present invention relates to the following coating method, inkjet head, and coating device.

[0009] A coating method for coating a substrate with a solution containing a perovskite compound or a precursor thereof and a solvent by ejecting the solution from a nozzle of an inkjet head, wherein the solvent contains one or more aprotic polar solvents having a relative dielectric constant of 30 or more, and the inkjet head has a vibration plate that operates in response to application of a drive signal to a piezoelectric element, a pressure chamber whose volume expands or contracts in response to operation of the vibration plate, a flow path that supplies the solution to the pressure chamber, and an elastic member that faces the flow path and is disposed opposite the vibration plate, and wherein the volume of the pressure chamber expands or contracts in response to application of a drive signal to the piezoelectric element. an inkjet head that discharges the solution in the pressure chamber from a nozzle by driving the piezoelectric element; and the drive signal includes one or more drive signal waveform elements that apply, in succession in this order, an expansion pulse that moves from the reference potential via the expansion potential and back to the reference potential, and a contraction pulse that moves from the reference potential via the contraction potential and back to the reference potential, where the potential applied to the piezoelectric element when it is not driven is defined as a reference potential, a potential that causes a displacement that expands the volume of the pressure chamber compared to the reference potential is defined as an expansion potential, and a potential that causes a displacement that contracts the volume of the pressure chamber compared to the reference potential is defined as a contraction potential.

[0010] An inkjet head that ejects a solution containing a perovskite compound or a precursor thereof and an aprotic polar solvent having a relative dielectric constant of 30 or more, a vibration plate that operates in response to application of a drive signal to a piezoelectric element; a pressure chamber whose volume expands or contracts in response to operation of the vibration plate; a flow path that supplies the solution to the pressure chamber; and an elastic member that faces the flow path and is disposed opposite the vibration plate; and the volume of the pressure chamber is expanded or contracted in response to application of a drive signal to the piezoelectric element, thereby ejecting the solution in the pressure chamber from a nozzle, The drive signal includes one or more drive signal waveform elements that apply successively in this order an expansion pulse that moves from the reference potential to the expansion potential and back to the reference potential, and a contraction pulse that moves from the reference potential to the contraction potential and back to the reference potential, where the potential applied to the piezoelectric element when it is not being driven is defined as a reference potential, a potential that causes a displacement that expands the volume of the pressure chamber compared to the reference potential is defined as an expansion potential, and a potential that causes a displacement that contracts the volume of the pressure chamber compared to the reference potential is defined as a contraction potential, and

[0011] A coating device that coats a coating target with a solution containing a perovskite compound or a precursor thereof and an aprotic polar solvent having a relative dielectric constant of 30 or more, the coating device comprising: an inkjet head that ejects the solution from a nozzle; and a control unit that controls driving of the inkjet head; The inkjet head comprises: a vibration plate that operates when a drive signal is applied to a piezoelectric element; a pressure chamber whose volume expands or contracts in response to the movement of the vibration plate; a flow channel for supplying the solution to the pressure chamber; an elastic member facing the flow path and disposed opposite the vibration plate, wherein the volume of the pressure chamber is expanded or contracted by applying a drive signal to the piezoelectric element, thereby ejecting the solution in the pressure chamber from a nozzle; The control unit The coating device applies to the piezoelectric element, as the drive signal, a drive signal including one or more drive signal waveform elements that apply successively in this order an expansion pulse that moves from the reference potential via the expansion potential and back to the reference potential, and a contraction pulse that moves from the reference potential via the contraction potential and back to the reference potential, where the potential applied to the piezoelectric element when it is not being driven is defined as a reference potential, a potential that causes a displacement that expands the volume of the pressure chamber compared to the reference potential is defined as an expansion potential, and a potential that causes a displacement that contracts the volume of the pressure chamber compared to the reference potential is defined as a contraction potential. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a solution application method that can apply a solution containing a perovskite crystal material by an inkjet method and that can suppress ejection defects, as well as an inkjet head and application device used therefor. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing the general configuration of a coating apparatus according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic perspective view of an inkjet head. [Figure 3] FIG. 3 is a schematic cross-sectional view of a main part of an inkjet head. [Figure 4] FIG. 4 is a schematic enlarged partial cross-sectional view of a laminated member. [Figure 5] FIG. 5 is an enlarged view of a portion of FIG. [Figure 6] 6A to 6F are signal waveform diagrams showing examples of drive signals. [Figure 7] 7A to 7D are signal waveform diagrams showing examples of drive signals. [Figure 8] FIG. 8 is a schematic cross-sectional view showing the main part of an ink-jet head according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0014] As described above, perovskite compounds and their precursors have a problem in that they have low solubility in conventional solvents and cannot be dissolved at high concentrations. As a result of extensive research, the present inventors have found that by using one or more aprotic polar solvents with a relative dielectric constant of 30 or more, perovskite compounds and their precursors can be dissolved at high concentrations.

[0015] On the other hand, solutions containing high concentrations of perovskite compounds or their precursors have high viscosity. It has been newly discovered that when ejecting such highly viscous solutions using the piezo inkjet method, problems such as droplet non-ejection and deviation in trajectory are likely to occur if ejected using a typical drive signal waveform. A typical drive signal waveform is, for example, a waveform that applies a voltage pulse to a piezoelectric element to expand the volume of the inkjet head's pressure chamber and then returns the voltage to the reference potential. As a result of further investigation, the inventors discovered that by using a DRR waveform, which expands the pressure chamber and then subsequently contracts it, as the drive signal waveform for ejecting droplets, droplets can be stably ejected even from highly viscous solutions such as those described above.

[0016] On the other hand, it has been newly discovered that when a DRR waveform is performed using a high-viscosity solution such as the one described above, the pressure vibration of the solution in the pressure chamber propagates to the surrounding area of ​​other pressure chambers through the common flow path or common liquid chamber, which tends to result in large variations in droplet speed between each ejection nozzle. After further investigation, the inventors discovered that by providing an elastic member in a position opposite the vibration plate that operates when a drive signal is applied to the piezoelectric element of the inkjet head, it is possible to suppress large variations in droplet speed between each ejection nozzle.

[0017] Hereinafter, an embodiment of the present invention will be described. However, the present invention is not limited to this embodiment. In this embodiment, a solution containing a perovskite compound or a precursor thereof is applied to a coating target by ejecting the solution from a nozzle of an inkjet head. First, an example of a solution used in this embodiment will be described.

[0018] 1. Solution The solution contains a perovskite compound or a precursor thereof and a solvent.

[0019] 1-1. Perovskite compounds or their precursors As the perovskite compound or a precursor thereof, for example, a known compound used in the power generation layer of a perovskite solar cell can be used.

[0020] Perovskite compounds are compounds represented by the formula ABX3, and have a crystal structure in which A is located at each vertex of a cubic lattice structure, B is located at the center of the cube, and X is located at the center of each face of the cube. In the formula, A is a monovalent cation, such as CH(NH2)2 + , CH3NH3 + , CH3CH2NH3 + , CH3CH2CH2NH3 + and C(NH2)=CHNH2 + and the like, preferably CH3NH3 + or CH(NH2)2 + B is a divalent cation, Pb 2+ or Sn 2+ Preferably, X is a halogen anion, and I - , Br - , Cl - It is preferable that either of the above is used.

[0021] Specific examples of perovskite compounds include CH3NH3PbI3, CH3CH2NH3PbI3, NH2CHNH2PbI3, CH3NH3PbBr3, and CH3NH3PbCl3. Also, CH3NH3SnCl3, CH3NH3SnBr3, CH3NH3SnI3, (NH2)2CHSnCl3, (NH2)2CHSnBr3, and (NH2)2 CHSnI3 and the like are also included.

[0022] A perovskite compound can be obtained, for example, by mixing an inorganic metal halide and an organic amine halide and then crystallizing the mixture. That is, the inorganic metal halide and the organic amine halide are precursors of the perovskite compound. The precursor forms a crystalline structure when applied as a solution and then dried.

[0023] The inorganic metal halide (BX) is a halide of at least one of Sn and Pb. An example of the inorganic metal halide is PbI2. The organic amine halide (AX) is represented by RNH3X, where R is a saturated alkyl group, an unsaturated alkyl group, or an aryl group. An example of the organic amine halide is methylammonium iodide (MAI).

[0024] The choice of whether to use a perovskite compound or a precursor can be determined depending on the method for forming the perovskite layer. For example, a solution containing a perovskite compound or its precursor (e.g., an inorganic metal halide and an organic amine halide) may be applied, and then a poor solvent may be applied to the coating film as needed, followed by drying to form the perovskite layer (a one-step method). Alternatively, a perovskite layer may be formed by applying a first solution containing an inorganic metal halide, followed by applying a second solution containing an organic amine halide to the coating film, followed by drying (a two-step method).

[0025] The content of the perovskite compound or precursor in the solution is not particularly limited as long as it can be ejected using an inkjet head, as described below. The content can be, for example, 0.6 mol / L or more and 2 mol / L or less, preferably 1.0 mol / L or more and 1.6 mol / L or less, and more preferably 1.2 mol / L or more and 1.4 mol / L or less, relative to the total volume of the solution. When the content of the perovskite compound or precursor is 0.6 mol / L or more, the coating amount per unit time can be increased, thereby further improving productivity. When the content of the perovskite compound or precursor is 2.0 mol / L or less, the solution can be ejected more stably from the nozzle of the inkjet head.

[0026] 1-2.Solvent The solvent includes one or more aprotic polar solvents having a relative dielectric constant of 30 or more.

[0027] (Aprotic polar solvents with a dielectric constant of 30 or more) The above-described perovskite compounds and their precursors (hereinafter simply referred to as "perovskite compounds, etc.") generally have low solubility in solvents. In contrast, aprotic polar solvents are good solvents, and among these, aprotic polar solvents with a relative dielectric constant of 30 or more have particularly high polarity, so they can dissolve highly polar perovskite compounds, etc., well. Therefore, perovskite compounds, etc. can be dissolved or dispersed in a solution at high concentrations.

[0028] The relative dielectric constant of the aprotic polar solvent can be preferably 32 or more. The upper limit of the relative dielectric constant of the aprotic polar solvent is not particularly limited, but can be, for example, 50 or less. That is, the relative dielectric constant can be 30 or more and 50 or less, preferably 32 or more and 50 or less.

[0029] Examples of aprotic polar solvents having a dielectric constant of 30 or more include N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAC), dimethyl sulfoxide (DMSO), and 1,3-dimethyl-2-imidazolidinone (DMI). The solution may contain only one aprotic polar solvent having a relative dielectric constant of 30 or more, or may contain two or more aprotic polar solvents.

[0030] The relative dielectric constant of the aprotic polar solvent can be measured using a dielectric constant meter (for example, manufactured by Agilent) under conditions of 25° C. and a frequency of 1 MHz.

[0031] In addition, the SP value of aprotic polar solvents with a relative dielectric constant of 30 or more is 11 (cal / cm) 1 / 2 More than 15 (cal / cm) 1 / 2A solvent having such an SP value has an SP value close to that of the solute, such as a perovskite compound, and therefore can further increase the solubility.

[0032] In this specification, the SP value (solubility parameter) is a value expressed as the square root of the molecular cohesive energy. The SP value δ [unit: (cal cm 3 ) 1 / 2 (JH Hildebrand and RL Scott, "The Solubility of Nonelectrolytes", Reinhold Publishing Corp., 1950). For the representative solvents shown in Table 1 below, the SP value of the solvent is the value listed in Table 1. [Table 1]

[0033] However, for solvents other than those listed in Table 1, the SP value of the solvent is a value calculated from the following formula (1).

number

[0034] From the viewpoint of increasing the solubility of the perovskite compound or the like and obtaining a solution containing the perovskite compound or the like at a high concentration, the solution preferably contains an aprotic polar solvent having a relative dielectric constant of 30 or more and satisfying the above SP value, and for example, preferably contains one or more solvents selected from the group consisting of N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), and dimethyl sulfoxide (DMSO).

[0035] The content of the aprotic polar solvent having a relative dielectric constant of 30 or more in the solvent contained in the solution is not particularly limited as long as it is sufficient to dissolve the perovskite compound, etc., and can be, for example, 50% by mass to 100% by mass, and preferably 60% by mass to 100% by mass, relative to the total mass of the solution. When the solvent further contains a poor solvent, the upper limit of the content of the aprotic polar solvent having a relative dielectric constant of 30 or more in the solvent can be, for example, 95% by mass or less.

[0036] (other solvents) The solvent may further contain a solvent other than the aprotic polar solvent having a relative dielectric constant of 30 or more. A poor solvent is preferable as the other solvent. A poor solvent is a solvent that has the ability to dissolve the solute, such as a perovskite compound, but has low solubility for the solute. Examples of poor solvents include substituted aliphatic hydrocarbons such as dichloromethane and chloroform; aromatic hydrocarbons such as toluene and benzene; substituted aromatic hydrocarbons such as chlorobenzene, orthodichlorobenzene, and nitrobenzene; ethers such as acetic acid, diethyl ether, and tetrahydrofuran (THF); alcohols such as methanol, ethanol, isopropanol, butanol, and octanol; long-chain hydrocarbons (particularly C4-10 hydrocarbons) such as hexane; and acetonitrile. These poor solvents can be used alone or in combination of two or more. Among these, chlorobenzene or toluene is preferable.

[0037] 1-3.Other ingredients The solution may further contain other components in addition to the perovskite compound and the solvent, as needed, such as a resin, a curable compound, a curing agent, and a filler. Resins include fluorine-based resins such as polyvinylidene fluoride resin (PVDF), cellulose ester resin, polysulfone (PSF), aromatic polyamide (PA), polyimide (PI), polycarbonate (PC), and polystyrene (PS). Curable compounds include photocurable compounds such as (meth)acrylate compounds, thermosetting compounds such as epoxy compounds, and siloxane compounds. Curing agents may be any that can cure these curable compounds, including photopolymerization initiators and curing catalysts. Examples of fillers include silica, boron nitride nanosheets, graphene, and carbon nanotubes.

[0038] Next, the coating device of this embodiment will be described with reference to the accompanying drawings. However, the coating device is not limited to the illustrated example. In the following description, components having the same functions and configurations are designated by the same reference numerals, and their description will be omitted.

[0039] 2. Coating equipment 1 is a schematic diagram showing the general configuration of a coating apparatus 100 according to this embodiment. Note that, although an example of a coating apparatus using a line head will be described, the present invention is not limited to this.

[0040] The coating apparatus 100 includes a conveying unit 200, a solution applying unit 300, a solution supplying unit 400, and a control unit 500. In the coating apparatus 100, under the control of the control unit 500, the solution applied by the solution applying unit 300 is applied to the recording medium R being conveyed by the conveying unit 200 with the solution supplied from the solution supplying unit 400.

[0041] The transport unit 200 holds the recording medium R and supplies it to the solution coating unit 300. The transport unit 200 has an unwinding roll 210, rollers 220 and 230, and a take-up roll 240. The long recording medium R wound in a roll is unwound from the unwinding roll 210, transported while being supported by the rollers 220 and 230, and taken up by the take-up roll 240.

[0042] The solution coating unit 300 forms a coating layer by ejecting a solution onto the recording medium R. The solution coating unit 300 includes a plurality of line heads 310 and a carriage 330 that holds the line heads 310. Preferably, the solution coating unit 300 further includes a heating unit 320.

[0043] The line head 310 ejects the solution onto the recording medium R being transported by the transport unit 200. In Fig. 1, there are two line heads 310, and the line heads 310, 310 corresponding to the solution containing the perovskite compound and the like and the poor solvent are provided in this order from upstream in the transport direction of the recording medium R by the transport unit 200.

[0044] The line head 310 of this embodiment is provided on the carriage 330 with a length (width) sufficient to cover the entire recording medium R in a direction (width direction) substantially perpendicular to the conveyance direction of the recording medium R. In other words, the coating device 100 is a one-pass line head type inkjet device. The line head 310 is configured by arranging a plurality of inkjet heads 1 (see FIG. 2). As shown in the figure, the carriage 330 may be provided with a carriage heater 330a to heat the solution.

[0045] The heating unit 320 is provided downstream of the line head 310 in the transport direction of the recording medium R. The heating unit 320 can be, for example, a heater. The heating unit 320 heats the recording medium R onto which the solution has been ejected, thereby drying the solution ejected onto the recording medium R.

[0046] The solution supply unit 400 includes a tank 410 , a pump 420 , a tube 430 , a sub-tank 440 , a tube 450 , and a heater 460 . The solution supply unit 400 stores the solution and supplies the solution to the line head 310 of the solution application unit 300, enabling the predetermined solution to be ejected from each nozzle of the line head 310. The solution in the tank 410 is sent by a pump 420 through a tube 430 to a sub-tank 440 that adjusts the back pressure of the solution in the inkjet head 1. The subtank 440 is provided with a float sensor 440a, and the control unit 500 drives the pump 420 based on detection data of the liquid level position by the float sensor 440a, thereby storing a predetermined amount of the solution. The solution in the subtank 440 is supplied to the inkjet head 1 via a tube 450. Note that, in this example, a configuration including the tank 410, the pump 420, the tube 430, the subtank 440, the tube 450, and the heater 460 has been exemplified, but the configuration is not limited to this. Various configurations can be applied as long as the solution can be supplied to the inkjet head 1.

[0047] The solution supply unit 400 is also provided with a heater 460, which constitutes an external heater that heats the solution outside the inkjet head 1. In the example shown in FIG. 1, the heater 460 is provided so as to cover the entire solution supply unit 400, but it may also be provided individually on any of the components that constitute the solution supply unit 400. This heats and keeps the solution in the solution supply unit 400 warm, so that the temperature of the solution is maintained at or above a predetermined temperature. The heater 460 is, for example, formed of an electric heating wire or a heat transfer member, and is provided by covering each component that constitutes the solution supply unit 400 or by being attached to the outer surface of the component that constitutes the solution supply unit 400.

[0048] The control unit 500 controls the driving of each part (e.g., the inkjet head 1) of the coating device 100 and supervises the overall operation. The control unit 500 includes a CPU (Central Processing Unit), The system includes a ROM (Read Only Memory), a RAM (Random Access Memory), etc. The control unit 500 reads out various processing programs, such as a system program, stored in the ROM and loads them into the RAM. The programs loaded into the RAM are then executed by the CPU, thereby performing various processes, such as the coating process and the above-mentioned solution supply process. In the coating process, for example, the control unit 500 operates a driver 5 (described later) to generate a drive signal for driving the piezoelectric element 42.

[0049] [Inkjet head configuration] FIG. 2 is a schematic perspective view of the inkjet head 1. FIG. 3 is a schematic cross-sectional view of a main part of the inkjet head 1. In FIG. 3, for ease of viewing, only the components related to some of the multiple nozzles 11 are enlarged and illustrated. The X axis is the arrangement direction of the nozzles 11 in the longitudinal direction of the laminated member 2, the Y axis is an axis perpendicular to the X axis within the surface (discharge surface) on which the nozzles 11 of the laminated member 2 are placed and from which the solution is discharged, and the Z axis is an axis perpendicular to the XY plane and is the stacking direction.

[0050] The inkjet head 1 has a laminated member 2 having a plurality of nozzles 11, a common liquid chamber forming member 6, a flexible substrate 4, and a driver 5 (see FIG. 3).

[0051] The laminated member 2 is formed by laminating a plurality of flow path forming members (layer members) via an adhesive in the Z direction, which is the lamination direction. At the lower end of the laminated member 2, a plurality of nozzles 11 for discharging a solution are arranged in the X and Y directions.

[0052] The type of adhesive used to bond the multiple layer members is not particularly limited. For example, a room temperature curing adhesive, a heat curing adhesive, an active energy ray curing adhesive, etc. may be used. For example, an adhesive using a fluorine-based resin, an epoxy-based resin, a polyimide-based resin, etc. may be used, and an epoxy-based adhesive containing an epoxy-based resin is preferred. These adhesives may also be conductive adhesives further containing metal particles such as Au or Ni. The absolute value of the difference between the SP value of the adhesive and the SP value of the aprotic polar solvent contained in the solution, which has an SP value of 11 to 15, is not particularly limited, but may be, for example, 4 (cal / cm) 1 / 2 The absolute value of the difference may be adjusted depending on the purpose. For example, from the viewpoint of suppressing the elution of the adhesive into the solution, the lower limit of the absolute value of the difference may be 0 (cal / cm). 1 / 2 It may be more than 1 (cal / cm) 1 / 2 It may be more than that.

[0053] The SP values ​​of representative adhesives are shown in Table 2 below. [Table 2]

[0054] However, the SP value of adhesives other than those shown in Table 2 above is a value calculated using formula (1) in the same manner as above. If the adhesive contains multiple components (for example, resin components), the SP value of the adhesive can be calculated using formula (2) below.

number

[0055] The common liquid chamber forming member 6 is disposed on and joined to the upper side of the laminated member 2. The space formed by the laminated member 2 and the common liquid chamber forming member 6 forms a common liquid chamber 3 that supplies solution to a plurality of nozzles 11.

[0056] The flexible substrate 4 and the driver 5 are members for driving the piezoelectric element 42, and are arranged on the upper side of the laminated member 2 at both ends in the X direction. The driver 5 is a drive signal generating unit that applies a drive signal for deforming the piezoelectric element 42 between the electrodes 421 and 422 (drive electrodes). The drive signal waveform applied by the driver 5 will be described in detail later.

[0057] Fig. 4 is a schematic partially enlarged cross-sectional view of the laminated member 2. Fig. 4 shows only the components related to one nozzle 11, but each component of the laminated member 2, except for the flow path forming member itself, is provided in plurality corresponding to each of the nozzles 11. Note that the adhesive is not shown in Fig. 4. Fig. 5 is an enlarged view of a portion around the damper 20 and the pressure chamber layer 30 in Fig. 4.

[0058] As shown in Figure 4, the laminated member 2 is composed of six flow path forming members, namely, a nozzle plate layer 10, a damper 20, a body plate layer 30, a protective substrate 40, a wiring layer 50, and a protective layer 60, stacked in this order in the Z direction.

[0059] The nozzle plate layer 10 is located at the bottom of the laminated member 2. The nozzle plate layer 10 has a base material 12 and a liquid-repellent layer 13. The base material 12 is, for example, a silicon substrate. The liquid-repellent layer 13 is disposed on the ejection surface side of the base material 12. The nozzle plate layer 10 has a plurality of nozzles 11 and a plurality of cavities 14 formed therein.

[0060] The nozzles 11 penetrate the substrate 12 and the liquid-repellent layer 13 in the Z direction. For example, eight nozzles 11 are arranged side by side in the X direction to form a nozzle row, and eight such nozzle rows are arranged side by side in the Y direction to form a nozzle group. More specifically, the nozzle groups are configured such that the X-direction positions of the nozzles 11 in all nozzle rows slightly overlap every other row, and so that the X-direction positions of all nozzles 11 as a whole slightly overlap. Two such nozzle groups are arranged side by side in the Y direction.

[0061] The cavity 14 is disposed on the upper surface of the base material 12 and forms a damper chamber for vibrating the damper 20. The damper 20 in this damper chamber deforms in response to the pressure of the solution in the common liquid chamber 3, thereby absorbing pressure fluctuations in the common liquid chamber 3. This makes it possible to suppress pressure fluctuations in the pressure chambers of other nozzles. In FIG. 3, the cavity 14 is formed as a closed cavity in a part of the thickness direction (Z direction) of the nozzle plate layer 10, but is not limited to this and may penetrate in the thickness direction and be connected to the outside.

[0062] The damper 20 (elastic member) is, for example, a flexible film. The material of the flexible film is not particularly limited as long as it can deform in response to pressure and absorb pressure vibrations. As shown in FIG. 4, the damper 20 is arranged so as to block at least the opening of the cavity 14. The damper 20 has a through-hole 201 formed therein, which communicates with the nozzle 11 of the nozzle plate layer 10. The arrangement of the damper 20 will be described later.

[0063] The body plate layer 30 includes a pressure chamber layer 31 and a diaphragm 32 . The pressure chamber layer 31 is, for example, a silicon substrate, and in this embodiment, is laminated and bonded to the upper surface of the damper 20. In the pressure chamber layer 31, a pressure chamber 311 that applies a discharge pressure to the solution discharged from the nozzle 11 is formed so as to penetrate the pressure chamber layer 31 in the Z direction. The pressure chamber 311 is provided above the through-hole 201 and the nozzle 11, and is in communication with these through-hole 201 and nozzle 11.

[0064] The pressure chamber layer 31 also has a communication flow path 312 that communicates with the pressure chamber 311 on the side opposite to the nozzle 11. In Fig. 4, the communication flow path 312 is formed in a serpentine shape by alternately arranged partition walls 31-1 and 31-2. The portion of the communication flow path 312 that extends from between the partition wall 31-1 and the damper 20 to between the partition walls 31-1 and 31-2 forms a throttle section 312A.

[0065] The diaphragm 32 is laminated and bonded to the upper surface of the pressure chamber layer 31 so as to cover the opening of the pressure chamber 311. In this embodiment, the diaphragm 32 constitutes part of the wall of the pressure chamber 311 (the upper wall portion in FIG. 4), and is deformed by application of a drive signal to the piezoelectric element 42. As a result, the volume of the pressure chamber 311 expands or contracts due to the operation of the diaphragm 32. An oxide film is formed on the surface of the diaphragm 32. In addition, the diaphragm 32 has a through-hole 321 formed therein that communicates with the communication hole 312.

[0066] The damper 20 is disposed facing the flow path (communicating flow path 312 in FIG. 4) that supplies the solution to the pressure chamber 311, and facing the vibration plate 32. In FIG. 4, a part of the vibration plate 32 faces the damper 20 in the region between the partition wall portion 31-1 and the partition wall portion 31-2. The damper 20 is disposed at a position that forms the throttle portion 312A of the communicating flow path 312. The damper 20 is deformed by the pressure inside the pressure chamber 311, thereby absorbing pressure fluctuations.

[0067] The protective substrate 40 is a substrate made of, for example, a 42 alloy, and has a space 41 formed therein to accommodate the piezoelectric element 42 and the like. In addition, the protective substrate 40 has a through-hole 401 formed therein as a supply flow path that penetrates in the vertical direction, independent of the space 41, and connects the common liquid chamber 3 and the pressure chamber 311.

[0068] The piezoelectric element 42 is formed in substantially the same shape as the pressure chamber 311 in a plan view, and is provided at a position facing the pressure chamber 311 across the vibration plate 32. The piezoelectric element 42 is an actuator made of PZT for deforming the vibration plate 32. The piezoelectric element 42 also has two electrodes 421, 422 provided on the top and bottom surfaces, and the electrode 422 on the bottom surface is connected to the vibration plate 32.

[0069] The wiring layer 50 has an interposer 51. The interposer 51 is a substrate made of, for example, silicon, and has two insulating layers 52 and 53 made of silicon oxide disposed on its lower surface, and an insulating layer 54, also made of silicon oxide, disposed on its upper surface. The lower of the insulating layers 52 and 53, the insulating layer 53, is stacked on and bonded to the upper surface of the protection substrate 40.

[0070] A through hole 511 is formed in the interposer 51 in the Z direction, and a through electrode 55 is inserted into this through hole 511. One end of an aluminum substrate 56 extending in the horizontal direction is connected to the lower end of the through electrode 55. A stud bump 561 is provided on the other end of the aluminum substrate 56, and the stud bump 561 is connected to an electrode 421 on the upper surface of the piezoelectric element 42 via solder 423 exposed in the space 41. The aluminum substrate 56 is also protected by being sandwiched between two insulating layers 52 and 53 on the lower surface of the interposer 51.

[0071] Furthermore, in the interposer 51, an inlet 512 communicating with the through hole 401 of the protection substrate 40 is formed so as to penetrate the interposer 51 in the Z direction. The inlet 512 is formed to have a smaller cross-sectional area (opening area) than the through holes 321, 401 and through hole 601 communicating with the inlet 512. Note that the portions of the insulating layers 52 to 54 that cover the vicinity of the inlet 512 are formed to have an opening diameter larger than that of the inlet 512.

[0072] The protective layer 60 is laminated and bonded to the upper surface of the insulating layer 54 of the interposer 51 while covering the copper substrate 61 disposed on the upper surface of the wiring layer 50. The protective layer 60 bonds the upper common liquid chamber forming member 6 to the laminated member 2 and also serves as a protective layer that protects the copper substrate 61. The protective layer 60 is made of an inorganic protective film such as silicon oxide or tantalum oxide. The copper substrate 61 extends horizontally, with one end connected to the upper end of the through electrode 55 and the other end connected to the flexible substrate 4 (see FIG. 3). Furthermore, the protective layer 60 has a through hole 601 formed in the Z direction that communicates with the inlet 512.

[0073] The copper substrate 61 and the through electrodes 55 may be made of copper, for example, but are not limited to this and may be made of other metals such as aluminum.

[0074] In this embodiment, the communicating flow path 312 (including the throttle portion 312A), the through holes 321, 401, the inlet 512, and the through hole 601 constitute a flow path that supplies a solution to the pressure chamber 311, and constitute an individual flow path 70 that communicates between the common liquid chamber 3 and the pressure chamber 311. Of these, the inlet 512 and the communicating flow path 312A, as described above, form throttle portions in the individual flow path 70. Note that the individual flow path 70 is formed by laminating a plurality of layer members (flow path forming members) with adhesive A interposed therebetween, and therefore a portion of the adhesive A is exposed to the individual flow path 70, and the exposed adhesive is not covered with a protective film (the portion surrounded by the dotted line in FIG. 5).

[0075] In the inkjet head 1 having the above configuration, the solution in the common liquid chamber 3 is supplied to the pressure chamber 311 through the individual flow path 70 (see the arrows in FIG. 4). Then, in response to a drive signal from the driver 5, a voltage is applied between the electrodes 421 and 422 through the flexible substrate 4, the copper substrate 61, the through electrode 55, and the aluminum substrate 56. This causes the piezoelectric element 42 sandwiched between the electrodes 421 and 422 to deform together with the vibration plate 32, and the solution in the pressure chamber 311 is pushed out and ejected from the nozzle 11. In other words, the volume of the pressure chamber 311 is expanded or contracted by application of a drive signal to the piezoelectric element 42, causing the solution in the pressure chamber 311 to be ejected from the nozzle 11.

[0076] In this embodiment, the flow path of the interposer 51 is not limited to the inlet 512, but may be a tapered (approximately conical) inlet 513 shown by the dotted line in Fig. 3. The inlet 513 has a structure in which the opening area in the XY plane decreases toward the nozzle in the Z direction, and is smaller than the opening area of ​​the through-hole 401.

[0077] Next, the waveform of the drive signal from the driver 5 will be described.

[0078] [Drive signal waveform by Driver 5] As described above, the driver 5 applies a drive signal for deforming the piezoelectric element 42 between the electrodes 421 and 422 (drive electrodes).

[0079] The drive signal provided to the drive electrode from the driver 5 includes one or more drive signal waveform elements (hereinafter also referred to as "DRR waveform element A") that apply, in succession in this order, an expansion pulse that goes from the reference potential to the expansion potential and back to the reference potential, and a contraction pulse that goes from the reference potential to the contraction potential and back to the reference potential, where the potential applied to the piezoelectric element 42 when it is not being driven is defined as a reference potential, a potential that causes a displacement that expands the volume of the pressure chamber 311 compared to the reference potential is defined as an expansion potential, and a potential that causes a displacement that contracts the volume of the pressure chamber 311 compared to the reference potential is defined as a contraction potential. By ejecting droplets using a drive signal waveform that includes one or more such drive signal waveform elements, stable ejection is possible even if the solution has a high viscosity.

[0080] Note that the reference potential does not necessarily have to be 0 V (the potential when the power is off), but can be any potential when not in operation. Furthermore, applying an expansion pulse and a contraction pulse consecutively does not include a section where the reference potential is maintained between the two pulses. In other words, the reference potential is simply passed when transitioning from the expansion pulse to the contraction pulse, but is not maintained.

[0081] 6A to 6F and 7A to 7D are diagrams showing examples of drive signals. Of these, FIGS. 6A to 6F are examples that correspond to the drive signal waveforms of this embodiment, and FIGS. 7A to 7D are examples that do not correspond to the drive signal waveforms of this embodiment. Each diagram shows an example of the waveform of one cycle. Furthermore, Vs indicates the reference potential, and the side above Vs indicates the potential that expands the volume of the pressure chamber 311, and the side below the reference potential indicates the potential that contracts the volume of the pressure chamber 311. The starting potential of each waveform diagram indicates the reference potential Vs.

[0082] In the DRR waveform element A, the expansion pulse Ph and contraction pulse Pl may include a slope portion in which the potential changes continuously within their respective sections (see FIG. 6A), or may include a sustain portion in which the potential is maintained (see FIG. 6B). The expansion pulse Ph and contraction pulse Pl may also include multiple sustain portions with different potentials within their respective sections (see FIG. 6C). The DRR waveform element A may be a square wave, a non-square wave, or a combination of these. The expansion potential and contraction potential of one DRR waveform element A1 or A3 may be different from the expansion potential and contraction potential of the other DRR waveform element A2 (see FIG. 6E). However, the expansion pulse never becomes a contraction potential, and the contraction pulse never becomes a contraction potential.

[0083] Furthermore, the drive signal waveform may include one or more consecutive DRR waveform elements A, and may further include a waveform element B other than the DRR waveform element A (see FIGS. 6D and 6F). For example, after a section (DRR waveform element A) in which an expansion pulse Ph and a contraction pulse Pl continue in this order, there may be another section (waveform element B) in which a contraction pulse Pl and an expansion pulse Ph continue in this order (see FIG. 6D). Furthermore, even if there is a section (waveform element B) in which a contraction pulse and an expansion pulse continue in this order, it is sufficient that there is a section (DRR waveform element A) in which an expansion pulse and a contraction pulse continue in this order after that (see FIG. 6F).

[0084] However, the solution is ejected by the above-mentioned DRR waveform element A. Specifically, by applying a contraction pulse (after an expansion pulse), the vibration plate 32 is deformed, the volume of the pressure chamber 311 is contracted, and a droplet is ejected. Therefore, the amount of change in the driving voltage, for example, the expansion potential (V H ) and contraction potential (V L) should be at least sufficient to eject droplets. Furthermore, if AL is half the acoustic resonance period, which is the natural vibration period of the pressure wave of the solution in pressure chamber 311, the times of the expansion pulse and contraction pulse, including the slope portion and the sustain portion, can be set to 0.9 AL or more and 1.1 AL or less, respectively, from the viewpoint of further improving ejection performance. The acoustic resonance period is the value obtained by measuring the velocity of droplets ejected when a square wave drive signal is applied between electrodes 421 and 422 (drive electrodes), and then doubling the pulse width at which the droplet flight velocity is maximized when the square wave voltage value is kept constant and the pulse width of the square wave is changed.

[0085] Note that the above-mentioned drive signal waveforms do not include a drive signal waveform that transitions from a contraction pulse to an expansion pulse (see FIG. 7A) or a drive signal waveform that has a section where the reference potential is maintained between expansion pulses (see FIG. 7B).Furthermore, a drive signal waveform that has only an expansion pulse between the reference potentials and does not include a contraction pulse (see FIG. 7C) also does not fall under the above-mentioned drive signal waveforms.

[0086] 6A to 6F and 7A to 7D show waveforms that are assumed to have expansion on the upper side and contraction on the lower side relative to the reference potential, but this is not limited to this. For example, depending on the type of head, there may be cases where the lower side expands and the upper side contracts relative to the reference potential. In such cases, the top and bottom of the waveforms in these figures will be reversed.

[0087] 3. Application method Next, the coating method of this embodiment will be described. In this embodiment, the solution is ejected from the nozzle 11 of the inkjet head 1 using the drive signal waveform. In this way, the solution is coated onto the object to be coated.

[0088] The type of object to be coated is not particularly limited. For example, when manufacturing a perovskite solar cell, the object to be coated can be a laminate having a substrate, an electrode, and an electron transport layer or a hole transport layer. Then, the solution is ejected from the nozzle of the inkjet head 1 onto the electron transport layer or the hole transport layer of the laminate.

[0089] Specifically, the control unit 500 (see FIG. 1) drives the driver 5, which then applies a drive signal between the electrodes 421 and 422 (drive electrodes). For example, when an expansion pulse such as that shown in FIG. 6A is applied, the vibration plate 32 deforms together with the piezoelectric element 42, expanding the volume of the pressure chamber 311. When a contraction pulse is subsequently applied from that state, the vibration plate 32 deforms together with the piezoelectric element 42, contracting the volume of the pressure chamber 311. By sequentially applying such an expansion pulse and a contraction pulse in this order, the volume change of the pressure chamber 311 increases, and sufficient pressure can be applied to the solution in the pressure chamber 311. This allows the solution in the pressure chamber 311 to be stably ejected, even if it is a highly viscous solution. This makes it possible to prevent droplets from failing to be ejected or droplets from landing incorrectly due to deviations in their trajectory.

[0090] On the other hand, when a solution is ejected using such a drive signal waveform, the pressure fluctuations within the pressure chamber 311 become large.

[0091] In particular, the flow paths of the inkjet head 1 (individual flow paths 70 in FIG. 4) are formed by laminating flow path forming members via adhesive A, as described above. Therefore, a part of adhesive A is exposed to the individual flow paths 70, and the exposed adhesive A is not covered with a protective film (see FIG. 5). Therefore, the exposed adhesive A is easily exposed to the solution being ejected. In particular, when the absolute value of the difference between the SP value of adhesive A and the SP value of a predetermined solvent contained in the solution is, for example, 4 (cal / cm), 1 / 2 If the SP value is less than this, adhesive A will dissolve in the solvent and adhere to the nozzle and its vicinity as the solution continues to be discharged. This makes it more likely that problems such as abnormal discharge (non-discharge, abnormal discharge trajectory) and wiring shorts caused by leakage of the solution into the flow path forming member will occur. In other words, the absolute value of the difference between the SP value of adhesive A and the SP value of the above solvent will be 4 (cal / cm). 1 / 2 If the driving waveform signal is less than this, the frequency of occurrence of problems increases significantly even when the head is used for a short period of time. Therefore, when the piezoelectric element 42 is driven with the driving waveform signal as described above, the pressure vibrations propagating within the individual flow paths 70 during solution ejection also become particularly large, which tends to increase the frequency of dissolution of the adhesive A at the points in contact with the individual flow paths 70 and the associated problems described above.

[0092] In contrast, in this embodiment, the inkjet head 1 has a damper 20 that faces the individual flow paths 70 and is disposed opposite the vibration plate 32 (see FIG. 3). This makes it possible to suppress pressure fluctuations in the pressure chambers 311 from propagating to the common liquid chamber 3 via the individual flow paths 70. This makes it possible to prevent variations in the speed of ejected droplets and the resulting deviation in landing position. In particular, since pressure vibrations that propagate to the points where the adhesive A contacts the individual flow paths 70 when the solution is ejected are suppressed, it is possible to suppress the adhesive A from dissolving and the associated problems described above.

[0093] 4. Manufacturing method of perovskite solar cells The above coating method can be applied to methods for forming perovskite layers and for manufacturing various devices using the same. Below, a method for manufacturing a perovskite solar cell using the above coating method will be described with reference to FIG.

[0094] A method for manufacturing a perovskite solar cell includes, for example, a step of preparing a stack of a substrate, an electrode, and an electron transport layer, and a step of forming a perovskite layer on the stack.

[0095] 1) A step of preparing a laminate The laminate may be, for example, a light-transmitting substrate on which an electrode and an electron transport layer are formed in this order.

[0096] 2) Step of forming a perovskite layer Next, a perovskite layer is formed on the laminate. For example, the solution containing the perovskite compound is applied to the laminate by the above-mentioned application method, and if necessary, a step of applying a poor solvent to the coating film, or a step of drying or annealing the coating film may be further carried out.

[0097] In the step of applying the solution, for example, in FIG. 1, the solution is discharged from the inkjet head of the upstream line head 310 by the application method described above, and applied onto the electron transport layer of the laminate.

[0098] In the step of applying the poor solvent, the poor solvent is applied to the coating film of the solution by ejecting the poor solvent from, for example, the inkjet head of the downstream line head 310. The poor solvent may be the same as the poor solvent used in the solution.

[0099] In the step of drying or annealing the coating film, the obtained coating film is dried by heating, for example, in the heating unit 320, to form a perovskite layer. The drying or annealing step is preferably carried out promptly after the coating step or after the poor solvent is dropped. In the annealing step, the coating film is preferably heated stepwise, for example, in a closed system containing solvent vapor.

[0100] When two types of precursor solutions are used (two-process method), for example, a first solution containing an inorganic metal halide may be discharged from the upstream line head 310-1, and then a second solution containing an organic amine halide may be discharged from the downstream line head 310-2. Then, the precursors may be crystallized by heating in the heating unit 320 to form a coating film (perovskite layer) containing a perovskite compound.

[0101] 3) Other processes Further steps such as forming a hole transport layer on the obtained perovskite layer and forming a back electrode may be carried out. This makes it possible to manufacture a perovskite solar cell having an element comprising a light-transmitting substrate, an electrode, an electron transport layer, a perovskite layer, a hole transport layer, and a back electrode. However, the structure of the perovskite solar cell element is not limited to this structure.

[0102] Furthermore, when a laminate of a substrate, an electrode, and a hole transport layer is used as the laminate, a step of forming a perovskite layer on the hole transport layer of the laminate and a step of forming an electron transport layer on the perovskite layer may be carried out.

[0103] 5. Variations In the above embodiment, the pressure chamber 311 of the inkjet head 1 is formed between the partition wall portion 31-2 and the pressure chamber layer 31, but the invention is not limited to this.

[0104] 8 is a schematic enlarged cross-sectional view of a portion of the inkjet head 1 according to a modified example. As shown in FIG. 8, for example, the space surrounded by the partition wall 31-2 and the vibration plate 32 may be used as the pressure chamber 311.

[0105] Furthermore, in the above embodiment, the flow path (individual flow path 70 in FIG. 4) that supplies the solution to the pressure chamber 311 includes portions (through holes 401, 601, inlets 512, 513) that penetrate the protective substrate 40, wiring layer 50, and protective layer 60, but is not limited to this. In short, the individual flow path 70 may be configured to supply the solution from the common liquid chamber 3 (or common flow path) to the pressure chamber 311, and may be configured to supply the solution to the pressure chamber 311 directly from the side surface of the pressure chamber layer 30, for example. In this case, the portions (through hole 401, inlets 512, 513, through hole 601) that penetrate the protective substrate 40 and wiring layer 50 are not necessary. Alternatively, in the communicating flow path 312 of Figure 4, the throttling section 312A and its downstream side (for example, between the partition wall 31-1 and the damper 20, between the partition wall sections 31-1 and 31-2, or between the partition wall section 31-2 and the vibration plate 32) may be considered as individual flow paths 70, and the upstream side of the throttling section 312A and the through hole 401 communicating with it may be considered as a common liquid chamber (or common flow path).

[0106] Furthermore, in the above embodiment, an example in which a line head is used as the coating device 100 has been described, but this is not limiting. For example, a scanning-type coating device that coats a solution by scanning an inkjet head in a direction perpendicular to the transport direction of the recording medium may be used. Furthermore, in the above embodiment, an example in which two line heads are provided is described, but this is not limiting and the number of line heads can be changed appropriately depending on the number of types of solution used, and may be one or three or more. Furthermore, in the above embodiment, an example in which a heating unit 320 that heats the solution ejected from the inkjet head 1 is provided is described, but this is not limiting and may be omitted depending on the drying method. [Industrial Applicability]

[0107] According to the present invention, a solution coating method that can coat a solution containing a perovskite compound or the like by an inkjet method and can suppress ejection defects, as well as an inkjet head and coating device used therefor, are provided. [Explanation of symbols]

[0108] 1 Inkjet head 2 Laminated members 3 Common liquid chamber 4 Flexible PCB 5 Driver 6 Common liquid chamber forming member 10 Nozzle Plate Layer 11 nozzles 12 Base material part 13 Liquid repellent layer 14 Cavity 20 Damper (elastic member) 30 Body Plate Layer 31 Pressure chamber layer 31-1, 31-2 Bulkhead section 32 Diaphragm 40 Protection board 41 Space section 42 Piezoelectric element 50 wiring layers 51 Interposer 52, 53 Insulating layer 55 Through electrode 56 Aluminum substrate 60 protective layer 61 Copper substrate 70 individual channels 100 Coating device 200 Conveyor 201, 321, 401, 601 through holes 300 Solution application section 311 Pressure Chamber 312 Connecting flow path 312A Constriction section 421, 422 electrode 512 Inlet 400 Solution supply unit 500 control section A adhesive

Claims

1. A coating method for coating a coating object with a solution containing a perovskite compound or a precursor thereof and a solvent by ejecting the solution from a nozzle of an inkjet head, comprising: the solvent contains one or more aprotic polar solvents having a relative dielectric constant of 30 or more; The inkjet head includes: a vibration plate that operates when a drive signal is applied to a piezoelectric element; a pressure chamber whose volume expands or contracts in response to the movement of the vibration plate; a flow channel for supplying the solution to the pressure chamber; an elastic member facing the flow path and disposed opposite the vibration plate; an inkjet head having a drive signal applied to the piezoelectric element to expand or contract the volume of the pressure chamber, thereby discharging the solution in the pressure chamber from a nozzle; In the inkjet head, the flow path is formed by laminating a plurality of flow path forming members with an adhesive therebetween, a portion of the adhesive is exposed to the flow path, and the exposed adhesive is not covered with a protective film; As the drive signal, when the potential applied to the piezoelectric element when it is not being driven is defined as a reference potential, the potential that causes a displacement that expands the volume of the pressure chamber compared to the reference potential is defined as an expansion potential, and the potential that causes a displacement that contracts the volume of the pressure chamber compared to the reference potential is defined as a contraction potential, a drive signal is used that includes one or more drive signal waveform elements that apply successively in this order an expansion pulse that goes from the reference potential via the expansion potential and then returns to the reference potential, and a contraction pulse that goes from the reference potential via the contraction potential and then returns to the reference potential. Application method.

2. The coating method according to claim 1, The SP value of the aprotic polar solvent is 11 to 15 (cal / cm) １／２ That is, Application method.

3. The coating method according to claim 1, The absolute value of the difference between the SP value of the aprotic polar solvent and the SP value of the adhesive is 4 (cal / cm) １／２ Below is the Application method.

4. The coating method according to claim 1, The adhesive is an epoxy adhesive. Application method.

5. The coating method according to any one of claims 1 to 4, the solvent includes one or more selected from the group consisting of N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), and dimethyl sulfoxide (DMSO); Application method.

6. The coating method according to any one of claims 1 to 4, The perovskite compound has the composition formula ABX ３ (A is a monovalent cation, B is a divalent cation, and X is a halogen anion), and has a crystal structure in which A is located at each vertex of a cubic lattice structure, B is located at the center of the cube, and X is located at the center of each face of the cube, A is CH ３ NH ３ ＋ or HC(NH ２ ) ２ ＋ and B is Pb ２＋ or Sn ２＋ and X is I － ,Br － , Cl － Either Application method.

7. The coating method according to any one of claims 1 to 4, In the inkjet head, the elastic member is disposed at a position that forms a throttle portion of the flow path. Application method.

8. The coating method according to any one of claims 1 to 4, The precursor has the formula ABX ３ (A is a monovalent cation, B is a divalent cation, and X is a halogen anion), Application method.

9. The coating method according to claim 8, The precursor forms a crystalline structure by applying the solution and then drying it. Application method.

10. An inkjet head that ejects a solution containing a perovskite compound or a precursor thereof and an aprotic polar solvent having a relative dielectric constant of 30 or more, a vibration plate that operates when a drive signal is applied to a piezoelectric element; a pressure chamber whose volume expands or contracts in response to the movement of the vibration plate; a flow channel for supplying the solution to the pressure chamber; an elastic member facing the flow path and disposed opposite the vibration plate; a volume of the pressure chamber is expanded or contracted by applying a drive signal to the piezoelectric element, thereby discharging the solution in the pressure chamber from a nozzle; the flow path is formed by laminating a plurality of flow path forming members with an adhesive, a portion of the adhesive is exposed to the flow path, and the exposed adhesive is not covered with a protective film; The drive signal includes one or more drive signal waveform elements that apply successively in this order an expansion pulse that moves from the reference potential to the expansion potential and back to the reference potential, and a contraction pulse that moves from the reference potential to the contraction potential and back to the reference potential, where the potential applied to the piezoelectric element when it is not being driven is defined as a reference potential, a potential that causes a displacement that expands the volume of the pressure chamber compared to the reference potential is defined as an expansion potential, and a potential that causes a displacement that contracts the volume of the pressure chamber compared to the reference potential is defined as a contraction potential. Inkjet head.

11. A coating device that coats a coating object with a solution containing a perovskite compound or a precursor thereof and an aprotic polar solvent having a relative dielectric constant of 30 or more, an inkjet head that ejects the solution from a nozzle; a control unit that controls the driving of the inkjet head; Equipped with The inkjet head comprises: a vibration plate that operates when a drive signal is applied to a piezoelectric element; a pressure chamber whose volume expands or contracts in response to the movement of the vibration plate; a flow channel for supplying the solution to the pressure chamber; an elastic member facing the flow path and disposed opposite the vibration plate; a volume of the pressure chamber is expanded or contracted by applying a drive signal to the piezoelectric element, thereby discharging the solution in the pressure chamber from a nozzle; the flow path is formed by laminating a plurality of flow path forming members with an adhesive, a portion of the adhesive is exposed to the flow path, and the exposed adhesive is not covered with a protective film; The control unit As the drive signal, when the potential applied to the piezoelectric element when it is not being driven is defined as a reference potential, the potential that causes a displacement that expands the volume of the pressure chamber compared to the reference potential is defined as an expansion potential, and the potential that causes a displacement that contracts the volume of the pressure chamber compared to the reference potential is defined as a contraction potential, a drive signal including one or more drive signal waveform elements that apply successively in this order an expansion pulse that moves from the reference potential via the expansion potential and back to the reference potential, and a contraction pulse that moves from the reference potential via the contraction potential and back to the reference potential is applied to the piezoelectric element. Coating equipment.

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