Method for manufacturing formamidine for perovskite materials for ALD deposition

Abstract

Disclosed is a method for manufacturing formamidine for perovskite materials for atomic layer deposition (ALD). The method for manufacturing formamidine according to the present invention comprises the steps of: (a) maintaining the temperature of a reactor at or below 20°C; (b) introducing a formamidine-acid compound, a basic compound, and water into the reactor; and (c) maintaining the temperature of the reactor at 60-70°C, and then raising the temperature to 70-80°C to manufacture the formamidine.

Description

Method for preparing formamidine for perovskite materials for ALD deposition

[0001] The present invention relates to a method for preparing formamidine for ALD (Atomic layer deposition) deposition and a method for preparing a perovskite containing the same.

[0002] The rapid expansion of research in the field of perovskite solar cells (PSCs) is primarily due to the relatively inexpensive solution processing and the excellent optoelectronic properties of perovskite films.

[0003] Perovskites have an adjustable band gap, a high absorption coefficient, a low carrier recombination rate, and high carrier mobility.

[0004] Due to these optoelectronic properties, perovskites are attracting attention for their potential to be commercialized as next-generation photovoltaic materials.

[0005] Recently, research on continuous perovskite compositions from MAPbI3 (methylammonium lead triiodide) to FAPbI3 (formamidinium lead triiodide) has been ongoing.

[0006] Formamidine (FA), primarily used in perovskites, is a very important raw material for FAPbI3, which is used as a photoactive layer in perovskite solar cells.

[0007] Commercially used formamidine substances are utilized in the form of salts, such as FA-acetate and FA-HCl. Formamidine is primarily used in solution processes due to its ease of application. It is convenient to dissolve solid formamidine substances in a solvent for use.

[0008] However, solution processes are difficult to use to realize large-area perovskite layers.

[0009] To solve these problems, the Atomic Layer Deposition (ALD) method is currently being studied.

[0010] For formamidine to be applied to the ALD deposition method, it must have a high vapor pressure, but it is too low to be used in the vacuum deposition method, with a vapor pressure of 0.001 torr or less, which poses many difficulties in the deposition process.

[0011] Therefore, there is a need for research on formamidine that can be easily used in deposition processes.

[0012] The objective of the present invention is to provide a method for manufacturing formamidine for perovskite materials for ALD deposition that can be applied to a vacuum deposition method by increasing the vapor pressure to approximately atmospheric pressure.

[0013] In addition, the objective of the present invention is to provide a method for preparing formamidine for perovskite materials for ALD deposition, which is a gas at room temperature, a liquid state at -50°C or lower, and can be maintained stably.

[0014] In addition, the objective of the present invention is to provide a method for producing formamidine for perovskite materials for ALD deposition capable of exhibiting high yield.

[0015] In addition, the objective of the present invention is to provide a method for manufacturing perovskite using a method for manufacturing formamidine.

[0016] The objects of the present invention are not limited to those mentioned above, and other unmentioned objects and advantages of the present invention may be understood from the following description and will be more clearly understood by the embodiments of the present invention. Furthermore, it will be readily apparent that the objects and advantages of the present invention can be realized by the means and combinations thereof set forth in the claims.

[0017] The method for producing formamidine according to the present invention is characterized by comprising: (a) a step of maintaining the reactor temperature at 20°C or lower; (b) a step of introducing a formamidine-acid compound, a basic compound, and water into the reactor; and (c) a step of maintaining the reactor temperature at 60°C to 70°C and then raising the temperature to 70°C to produce formamidine.

[0018] The acid in the above formamidin-acid compound may include one or more of acetate, hydrochloric acid, bromic acid, iodic acid, nitric acid, and sulfuric acid.

[0019] The above basic compound may include one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

[0020] For 500g of the above formamidin acid compound, 400 to 800g of a basic compound and 120 to 250g of water can be mixed.

[0021] Step (c) above can be performed for 1 to 5 hours.

[0022] The above formamidine is a gas at 25±2℃ and may be a liquid at -50℃ or lower.

[0023] The method for manufacturing a perovskite according to the present invention is characterized by comprising the step of depositing formamidine by atomic layer deposition (ALD) using the method for manufacturing formamidine.

[0024] The above deposition can be performed at 100 to 130°C and 0.2 torr or higher.

[0025] The method for manufacturing formamidine according to the present invention can be applied to a vacuum deposition method by raising the vapor pressure to approximately atmospheric pressure.

[0026] In addition, through the method for manufacturing formamidine, it is possible to produce formamidine that is a gas at room temperature, a liquid at -50℃ or lower, and can be maintained stably.

[0027] In addition, high-yield formamidine can be produced.

[0028] In addition, perovskite can be produced using the method for producing formamidine of the present invention.

[0029] In addition to the effects described above, the specific effects of the present invention are described together with the specific details for implementing the invention below.

[0030] The aforementioned objectives, features, and advantages are described in detail below with reference to the attached drawings, thereby enabling those skilled in the art to easily implement the technical concept of the present invention. In describing the present invention, detailed descriptions of known technologies related to the present invention are omitted if it is determined that such descriptions would unnecessarily obscure the essence of the invention. Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. In the drawings, the same reference numerals are used to indicate the same or similar components.

[0031] In the following, the statement that any configuration is placed on the "upper (or lower)" of a component or on the "upper (or lower)" of a component may mean not only that any configuration is placed in contact with the upper (or lower) surface of said component, but also that another configuration may be interposed between said component and any configuration placed on (or below) said component.

[0032] In addition, where it is stated that one component is "connected," "combined," or "connected" to another component, it should be understood that while the components may be directly connected or connected to each other, another component may be "interposed" between each component, or each component may be "connected," "combined," or "connected" through another component.

[0033] Hereinafter, a method for preparing formamidine for perovskite materials for ALD deposition according to some embodiments of the present invention will be described.

[0034] The method for producing formamidine according to the present invention can produce stable formamidine by distilling and purifying it at a low temperature using an acid and a base in a sealed reactor isolated from external air, and then storing it in a dedicated canister.

[0035] In particular, the method for producing formamidine according to the present invention has the advantage of being applicable to a vacuum deposition method by raising the vapor pressure of formamidine to approximately atmospheric pressure.

[0036] In addition, the manufacturing method of the present invention has the effect of producing high-yield formamidine.

[0037] The formamidine produced in the present invention is a gas at room temperature, a liquid at -50℃ or lower, and has the effect of remaining stable.

[0038] The method for producing formamidine according to the present invention is characterized by comprising the steps of: (a) maintaining the reactor temperature at 20°C or lower; (b) introducing a formamidine-acid compound, a basic compound, and water into the reactor; and (c) maintaining the reactor temperature at 60°C to 70°C and then raising the temperature to 70°C to produce formamidine.

[0039] It is desirable to maintain the reactor temperature at 20℃ or lower.

[0040] The present invention proceeds as an exothermic reaction because a formamidine acid compound reacts with a basic compound. If the exothermic reaction is severe, when the formamidine acid compound is neutralized and synthesized into formamidine, it is in a gaseous state, and there may be a risk of explosion due to high temperature and high vapor pressure. It is important to control the reaction at a low temperature to ensure phase stability; to this end, it is desirable to maintain the reactor temperature at 20°C or lower, and more desirable to maintain it at 0 to 20°C.

[0041] If the reactor temperature is too low, the reaction time becomes significantly longer, so it can be maintained at 20℃ or lower for reaction efficiency.

[0042] The method for producing formamidine according to the present invention comprises the step of introducing a formamidine-acid compound, a basic compound, and water into a reactor.

[0043] In the formamidin-acid compound, the acid may include one or more of acetate, hydrochloride, bromic acid, iodic acid, nitric acid, and sulfuric acid, and preferably one or more of acetate and hydrochloride.

[0044] The basic compound may include one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate, and preferably may include one or more of sodium hydroxide and sodium carbonate.

[0045] For every 500g of formamidin acid compound, 400 to 800g of basic compound and 120 to 250g of water can be mixed.

[0046] Preferably, 500 to 700 g of a basic compound and 200 to 250 g of water can be mixed with 500 g of a formamidin acid compound.

[0047] More preferably, 600 to 700 g of a basic compound and 210 to 240 g of water can be mixed with 500 g of a formamidin acid compound.

[0048] For every 500g of formamidin acid compound, 400 to 800g of basic compound and 120 to 250g of water are used, so that the reaction proceeds sufficiently and a high yield of formamidin can be secured.

[0049] The molar ratio of the formamidin acid compound to the basic compound can satisfy 1:1.5 to 2.0, and preferably 1:1.8 to 1.9.

[0050] By satisfying a molar ratio of formamidin acid compound to basic compound of 1:1.5 to 2.0, the yield is improved.

[0051] The concentration of an aqueous solution of a basic compound can vary depending on the water content.

[0052] For example, the aqueous solution concentration of the basic compound of the present invention may be 50 to 80%, and preferably 60 to 80%.

[0053] The method for producing formamidine according to the present invention includes the step of maintaining the reactor temperature at 60 to 70°C and then raising the temperature to 70 to 80°C to produce formamidine.

[0054] In the process of acid-base neutralization, a large amount of salt is produced by the acid-base reaction when the neutralization reaction is nearing completion. At this time, the remaining formamidine acid compound does not react well. To terminate the reaction, the acid-base reaction can be terminated by raising the temperature to 60 to 70°C in the final step.

[0055] The step of preparing the formamidine above can be performed for 1 to 5 hours, and preferably for 1 to 3 hours.

[0056] In particular, the highest possible yield can be secured by raising the temperature to 70 to 80°C.

[0057] For example, after reacting at 60 to 70°C for a certain period of time, the temperature can be raised to a maximum of 80°C for purification, and in this step, the reaction can be carried out for a total of 3 hours.

[0058] In the step of introducing a formamidin acid compound, a basic compound, and water into the reactor, after introducing the basic compound, the product begins to appear when the temperature is raised to 60 to 70°C, passing through about 40°C. As the temperature continues to rise, the product can be continuously purified and produced at 60 to 70°C.

[0059] And finally, if it appears that no more product is being produced, the temperature can be further increased to a maximum of 80°C to secure the maximum yield.

[0060] The above formamidine is a gas at 25±2℃ and may be a liquid at -50℃ or lower.

[0061] In the present invention, the method for manufacturing formamidine involves purifying it while maintaining a temperature of -50°C or lower, at which point it becomes liquefied. Even when maintained at -50°C or lower, the amount of formamidine continues to decrease during long-term storage due to its volatility.

[0062] Therefore, it is advisable to store the product at a temperature lower than -50℃ after purification. It can be stored in a SUS canister, which poses no risk of explosion even if the vapor pressure increases as the temperature of the storage container rises.

[0063] The method for manufacturing a perovskite according to the present invention is characterized by including a step of depositing formamidine by atomic layer deposition (ALD) using the method for manufacturing formamidine.

[0064] The above deposition can be performed at 100 to 130°C and 0.2 torr or higher, and preferably at 110 to 120°C and 0.5 torr or higher.

[0065] Increasing the deposition temperature of formamidine can increase its vapor pressure.

[0066] However, due to the characteristics of perovskite devices, deformation of the perovskite material may occur at high deposition temperatures, potentially preventing it from exhibiting its inherent performance. In other words, perovskite materials have the disadvantage of being vulnerable to heat.

[0067] Therefore, a lower deposition temperature of formamidine for manufacturing perovskite is advantageous.

[0068] From this perspective, the deposition temperature of formamidine can be 100 to 130°C.

[0069] In addition, a higher vapor pressure of formamidine is advantageous and can be 0.2 torr or higher.

[0070] Since the deposition conditions of formamidine satisfy 100 to 130°C and 0.2 torr or higher, it has an advantageous effect for stably depositing formamidine.

[0071] Photovoltaic devices, such as solar cells, can be manufactured from the formamidine deposition of the present invention.

[0072] For example, a step of forming a photoactive layer (or light absorption layer) by depositing a formamidine composition on a substrate can be performed.

[0073] After the step of forming a photoactive layer, the step of heat-treating the photoactive layer and the step of applying an isopropanol solution containing octyl ammonium iodide onto the heat-treated photoactive layer may be performed, but is not limited thereto.

[0074] The manufactured deposition may include a cured product of the formamidine composition described above.

[0075] And, the above-mentioned deposit may be a photoactive film.

[0076] The solar cell structure containing perovskite is as follows.

[0077] The electron transport layer is located between the transparent conductive oxide (TCO) substrate and the perovskite layer.

[0078] The electron transport layer transports electrons excited in the perovskite light absorption layer to the transparent conductive glass substrate and prevents recombination by blocking the penetration of holes. Materials commonly used in the electron transport layer are inorganic metal oxides such as TiO2 and SnO2. For efficient electron injection and transport, characteristics such as high electron mobility, as well as band structure compatibility with the light absorption layer, are required.

[0079] The light absorbing layer contains a perovskite structure.

[0080] Perovskites are suitable for fabricating solar cells because they possess low binding energy, long carrier transport distances, and a broad light absorption band. Additionally, depending on the chemical composition of the material, the band gap ranges from 1.1 to 2.3 eV, and the easily adjustable band gap is one of the greatest advantages of perovskite solar cells. The photoelectric effect at a desired wavelength can be achieved through band gap tuning.

[0081] The hole transport layer not only improves the performance of the solar cell by transporting holes generated in the perovskite to the counter electrode, but also enhances long-term operational stability by protecting the perovskite layer from external factors such as humidity. To date, the most commonly used hole transport layers in perovskite solar cells are materials called Spiro-OMeTAD and PTAA.

[0082] The single molecule Spiro-OMeTAD has been continuously adopted in dye-sensitized solar cells, where it is utilized as a solid electrolyte and applied as a hole transport layer, preventing degradation by iodine.

[0083] These organic-based materials are widely used in perovskite solar cells because they are soluble in non-polar solvents that do not damage the perovskite layer and do not require heat treatment.

[0084] PTAA, a polymer, has a higher hole mobility than other polymer materials due to the inherent characteristic of having many holes.

[0085] PTAA possesses multiple benzene rings, and its pi (π) conjugated structure forms the channels necessary for hole transport. It is capable of appropriate energy level matching with perovskite, providing excellent hole extraction and electron backflow prevention capabilities.

[0086] A solar cell is a semiconductor device that absorbs light to produce electricity.

[0087] Performance factors such as short-circuit current (Isc), open-circuit voltage (Voc), fill factor (FF), and power conversion efficiency (PCE) are key elements that determine the performance and market value of solar cells.

[0088] Performance measurement is conducted through characteristic evaluation in accordance with standards set by the International Electrotechnical Commission (IEC).

[0089] In order to irradiate light in the same way as the characteristic evaluation of commonly used solar cells, virtual sunlight is irradiated through a solar simulator, which is a solar light simulation device, and the output values ​​from both ends of the solar cell are measured using the irradiated light.

[0090] The specific examples of the method for manufacturing formamidine for perovskite materials for ALD deposition are as follows.

[0091] 1. Preparation of Formamidine for ALD Deposition

[0092] Example 1

[0093] Before the raw material was introduced, a condenser column and a column filled with a molecular sieve were set up in the reactor, connected to a single distillation column, and a receiver was installed.

[0094] 224.8g of water, 673.7g of potassium hydroxide, and 500g of formamidine acetate were added while maintaining the internal temperature of the reactor at 20℃ or lower.

[0095] Afterward, the receiver was cooled with dry ice, and the reaction was carried out for 3 hours while heating the reactor temperature to 70℃.

[0096] When the internal solid was dissolved and bubbles were generated and stirred, the product was cooled by atmospheric distillation at 80°C to obtain 149.6g of the product, and the yield was 70.5%.

[0097] The product obtained at this time was analyzed using gas chromatography-mass spectrometry and confirmed to have a molecular weight of 44.1 g / mol.

[0098] Example 1 satisfies the manufacturing method of the present invention, in particular, the molar ratio of the formamidin acid compound to the basic compound is 1:1.9.

[0099] As a result, formamidine was stably produced and showed a high yield of over 70%.

[0100] Comparative Example 1

[0101] Before feeding the raw materials, a condenser column and a column filled with molecular sieves were set up in the reactor, connected to a single distillation column, and a receiver was installed.

[0102] 18g of water, 53.9g of potassium hydroxide, and 100g of formamidine acetate were added while maintaining the internal temperature of the reactor at 20℃ or lower.

[0103] Afterward, the receiver was cooled with dry ice, and the reaction was carried out for 3 hours while heating the reactor temperature to 70°C. When the internal solid dissolved and bubbles were generated and stirred, the product was cooled by atmospheric distillation at 80°C to obtain 15.95g of the product, with a yield of 37.7%.

[0104] The product obtained at this time was analyzed using gas chromatography-mass spectrometry and confirmed to have a molecular weight of 44.1 g / mol.

[0105] Comparative Example 1 was outside the range of basic compound and water content, and formamidine was not stably produced, showing a low yield of 40% or less.

[0106] Comparative Example 2

[0107] Before feeding the raw materials, a condenser column and a column filled with molecular sieves were set up in the reactor, connected to a single distillation column, and a receiver was installed.

[0108] While maintaining the internal temperature of the reactor at 20℃ or below, 134.8g of a 45% aqueous potassium hydroxide solution was added, followed by the addition of 100g of formamidine acetate. Subsequently, the receiver was cooled with dry ice, and the reaction was carried out for 3 hours while heating the reactor temperature to 70℃.

[0109] The product was cooled by atmospheric distillation at 80°C while stirring and bubbles were generated, yielding 13.96 g of the product, with a yield of 33%.

[0110] The product obtained at this time was analyzed using gas chromatography-mass spectrometry and confirmed to have a molecular weight of 44.1 g / mol.

[0111] Comparative Example 2 is a 45% aqueous solution made by dissolving KOH in water without using water separately.

[0112] Comparative Example 2 was a case where the water content was exceeded even when water was used as an aqueous solution of a basic compound, and formamidine was not stably produced, showing a low yield of 40% or less.

[0113] Comparative Example 3

[0114] Before feeding the raw materials, a condenser column and a column filled with molecular sieves were set up in the reactor, connected to a single distillation column, and a receiver was installed.

[0115] 134.8g of potassium hydroxide and 100g of formamidine acetate were added while maintaining the internal temperature of the reactor at 20℃ or below. Afterward, the receiver was cooled with dry ice, and the reaction was carried out for 3 hours while heating the reactor temperature to 70℃.

[0116] When the internal solid changed, the product was cooled by atmospheric distillation to obtain 9.73g of the product, and the yield was 23.0%.

[0117] The product obtained at this time was analyzed using gas chromatography-mass spectrometry and confirmed to have a molecular weight of 44.1 g / mol.

[0118] Comparative Example 3 did not use water separately, and formamidin was not stably produced, showing a low yield of 30% or less.

[0119] Comparative Example 4

[0120] Before feeding the raw materials, a condenser column and a column filled with molecular sieves were set up in the reactor, connected to a single distillation column, and a receiver was installed.

[0121] While maintaining the internal temperature of the reactor at 20℃ or lower, 58.1g of water, 174.3g of potassium hydroxide, and 100g of formamidine hydrochloride were added.

[0122] Afterward, the receiver was cooled with dry ice, and the reaction was carried out for 3 hours while heating the reactor temperature to 70°C. When the internal solid dissolved and bubbles were generated and stirred, the product was cooled by atmospheric distillation at 80°C to obtain 28.23g, and the yield was 51.6%.

[0123] The product obtained at this time was analyzed using gas chromatography-mass spectrometry and confirmed to have a molecular weight of 44.1 g / mol.

[0124] Comparative Example 4 was outside the range of basic compound and water content, and formamidine was not stably produced, showing a low yield of 51.6% or less.

[0125] Comparative Example 5

[0126] Before feeding the raw materials, a condenser column and a column filled with molecular sieves were set up in the reactor, connected to a single distillation column, and a receiver was installed.

[0127] 394.9g of water, 131.6g of sodium carbonate, and 100g of formamidine acetate were added while maintaining the internal temperature of the reactor at 20℃ or lower.

[0128] Afterward, the receiver was cooled with dry ice, and the reaction was carried out for 3 hours while heating the reactor temperature to 70℃.

[0129] The product was cooled by atmospheric distillation at 80°C while stirring and bubbles were generated, yielding 8.97g of the product, with a yield of 16.4%.

[0130] The product obtained at this time was analyzed using gas chromatography-mass spectrometry and confirmed to have a molecular weight of 44.1 g / mol.

[0131] Comparative Example 5 exceeded the water content, so formamidin was not stably produced, and showed a low yield of 20% or less.

[0132] Table 1 below lists the ratio of additives, purification yield, etc., according to Examples 1 to 5 above.

[0133] [Table 1]

[0134]

[0135] * Amount of water with H2O%-base concentration

[0136]

[0137] Example 1 satisfied the method for producing formamidine of the present invention, so the purification yield was 70% or higher.

[0138] However, Comparative Examples 1 to 5 had very low yields because the reaction did not proceed properly due to the content of basic compounds or / and water being outside the acceptable range.

[0139] Although the present invention has been described above with reference to the exemplary embodiments, the present invention is not limited by the embodiments disclosed in this specification, and it is obvious that various modifications can be made by a person skilled in the art within the scope of the technical concept of the present invention. Furthermore, even if the effects of the configuration according to the present invention were not explicitly described while explaining the embodiments of the present invention above, it is natural to acknowledge that the effects predictable by said configuration should also be recognized.

Claims

1. (a) A step of maintaining the reactor temperature at 20℃ or lower; (b) a step of introducing a formamidin acid compound, a basic compound, and water into the reactor; and (c) a step of maintaining the reactor temperature at 60 to 70°C and then raising the temperature to 70 to 80°C to produce formamidine; a method for producing formamidine comprising.

2. In Paragraph 1, In the above formamidine-acid compound A method for producing formamidine comprising one or more of the following acids: acetate, hydrochloric acid, bromic acid, iodic acid, nitric acid, and sulfuric acid.

3. In Paragraph 1, A method for producing formamidine comprising one or more of the basic compounds sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

4. In Paragraph 1, A method for preparing formamidine by mixing 400 to 800 g of a basic compound and 120 to 250 g of water with respect to 500 g of the above formamidine-acid compound.

5. In Paragraph 1, The above step (c) is a method for producing formamidine, performed for 1 to 5 hours.

6. In Paragraph 1, A method for producing formamidine, wherein the formamidine is a gas at 25±2℃ and a liquid at -50℃ or lower.

7. A method for manufacturing a perovskite comprising the step of depositing formamidine by atomic layer deposition (ALD) using the method for manufacturing formamidine according to claim 1.

8. In Paragraph 7, A method for manufacturing perovskite in which the above deposition is performed at 100 to 130°C and 0.2 torr or higher.

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