Perovskite solution and perovskite thin film forming method using same

Abstract

An embodiment of the present invention can provide a perovskite solution comprising: a perovskite compound or a perovskite precursor compound; a compound represented by chemical formula 1; and water. [Chemical formula 1] RCOOH In chemical formula 1, R is hydrogen or a C1-C3 alkyl group.

Description

Perovskite solution and method for forming a perovskite thin film using the same

[0001] The present invention relates to a perovskite solution and a method for forming a perovskite thin film using the same.

[0002]

[0003] To address the depletion of fossil fuels and the global environmental problems caused by their use, active research is being conducted on renewable and clean alternative energy sources such as solar energy, wind power, and hydropower. Among these, interest in solar cells, which directly convert sunlight into electrical energy, is growing significantly. A solar cell, in this context, refers to a battery that generates current and voltage by utilizing the photovoltaic effect, which generates electrons and holes by absorbing light energy from sunlight.

[0004]

[0005] Currently, it is possible to manufacture np diode-type silicon (Si) single crystal-based solar cells with a light energy conversion efficiency of over 20%, and these are actually being used for solar power generation. There are also solar cells using compound semiconductors such as gallium arsenide (GaAs) with even better conversion efficiencies. However, these inorganic semiconductor-based solar cells require highly purified materials to achieve high efficiency, so a lot of energy is consumed in refining the raw materials. In addition, expensive processing equipment is required in the process of forming single crystals or thin films using the raw materials, which limits the cost of lowering the manufacturing cost of solar cells, and this has been an obstacle to large-scale utilization.

[0006]

[0007] Accordingly, in order to manufacture solar cells at low cost, it is necessary to drastically reduce the cost of materials or manufacturing processes used as core components of solar cells, and research is being conducted on perovskite solar cells that can be manufactured using low-cost materials and processes as an alternative to inorganic semiconductor-based solar cells.

[0008]

[0009] Perovskite solar cells, which are organometallic halide compounds with the molecular formula (CH3NH3)PbX3, were first used as photoactive materials in solar cells in 2009. Since then, since the development of solid-state perovskite solar cells with the current structure in 2012, their efficiency has been rapidly improved. Conventional perovskite solar cells mainly use metal oxides as electron transport layers and organic or polymeric materials such as spiro-OMETAD as hole transport layers (HTL). That is, a porous film or thin film of metal oxide is formed on a transparent electrode such as FTO, and a perovskite solution is coated. After forming a hole transport layer, an electrode layer such as gold (Au) or silver (Ag) is deposited.

[0010]

[0011] Meanwhile, an anhydrous type reagent is used as a solvent to dissolve the perovskite precursor to prepare a perovskite solution, but this reagent is very expensive and has the problem of being difficult to handle. In addition, if a general mass-production solvent rather than an anhydrous type is used, water (H2O) may be mixed as an impurity, and if water is included, there is a problem of the perovskite compound and / or perovskite precursor being decomposed.

[0012]

[0013] One of the several objects of the present invention is to provide a perovskite solution that does not use an anhydrous type solvent and a method for forming a perovskite thin film using the same.

[0014]

[0015] One of the several objects of the present invention is to provide a perovskite solution capable of manufacturing solar cells using a mass-production solvent and a method for forming a perovskite thin film using the same.

[0016]

[0017] One of the several objects of the present invention is to provide a perovskite solution capable of suppressing decomposition of a perovskite compound and / or a perovskite precursor, and a method for forming a perovskite thin film using the same.

[0018]

[0019] The present invention has been devised to solve the above problems, and a perovskite solution according to one embodiment of the present invention may include a perovskite precursor or a perovskite compound; a compound represented by the following chemical formula 1; and water.

[0020] [Chemical Formula 1]

[0021] RCOOH

[0022] In chemical formula 1, R is hydrogen or a C1-C3 alkyl group.

[0023]

[0024] In one embodiment of the present invention, the perovskite compound may include a compound represented by the following chemical formula 2.

[0025] [Chemical Formula 2]

[0026] ABX3

[0027] In the above chemical formula 1, A is formamidinium, methylammonium, cesium, rubidium, potassium, sodium, lithium, guanidinium, butylammonium, ethylammonium or phenethylammonium, B is lead, tin, germanium, cadmium, zinc or manganese, and X is iodide, bromide, chloride, fluoride, thiocyanate, cyanate, selenocyanate, formate or It's acetate.

[0028]

[0029] In another embodiment of the present invention, the perovskite precursor may include at least one selected from formamidinium bromide (FABr), formamidinium iodide (FAI), methylammonium iodide (MAI), methylammonium bromide (MABr), methylammonium chloride (MACl), and an inorganic halogen compound.

[0030]

[0031] In one example, the compound represented by the above chemical formula 1 may be HCOOH.

[0032]

[0033] Meanwhile, the compound represented by the above chemical formula 1 may be included in an amount of 0.5% by volume or more and / or 9.0% by volume or less based on the entire perovskite solution.

[0034]

[0035] Additionally, the water may be included in an amount of 50 ppm or more relative to the entire perovskite solution.

[0036]

[0037] In one example of the present invention, the perovskite solution according to the present invention may further include one or more solvents selected from dimethyl sulfoxide (DMSO), dimethylformamide (DMF), N-methylformamide (NMF), gamma-butyrolactone (GBL), N-methyl-2-pyrrolidone (NMP), N-cyclohexyl-2-pyrrolidone (CHP), and N,N-dimethylpropyleneurea (DMPU).

[0038]

[0039] Another embodiment of the present invention provides a method for forming a perovskite thin film, comprising: forming a hole transport layer on a transparent substrate; coating a perovskite solution on the hole transport layer; and heat-treating the perovskite solution, wherein the perovskite solution includes a perovskite compound, a compound represented by the following chemical formula 1, and water.

[0040] [Chemical Formula 1]

[0041] RCOOH

[0042] In chemical formula 1, R is hydrogen or a C1-C3 alkyl group.

[0043]

[0044] At this time, the compound represented by the above chemical formula 1 may be included in a range of 0.5% by volume or more and / or 9.0% by volume or less based on the entire perovskite solution.

[0045]

[0046] Additionally, the water may be included in an amount of 50 ppm or more relative to the entire perovskite solution.

[0047]

[0048] Meanwhile, the perovskite solution of the perovskite thin film forming method according to the present invention may further include at least one solvent selected from dimethyl sulfoxide (DMSO), dimethylformamide (DMF), N-methylformamide (NMF), gamma-butyrolactone (GBL), N-methyl-2-pyrrolidone (NMP), N-cyclohexyl-2-pyrrolidone (CHP), and N,N-dimethylpropyleneurea (DMPU).

[0049]

[0050] One of the many effects of the present invention is that it can provide a perovskite solution that does not use an anhydrous type solvent and a method for forming a perovskite thin film using the same.

[0051]

[0052] One of the many effects of the present invention is to provide a perovskite solution capable of manufacturing solar cells using a mass-production solvent and a method for forming a perovskite thin film using the same.

[0053]

[0054] One of the various effects of the present invention is to provide a perovskite solution capable of suppressing decomposition of a perovskite compound and / or a perovskite precursor, and a method for forming a perovskite thin film using the same.

[0055]

[0056] However, the various advantageous advantages and effects of the present invention are not limited to the above-described contents, and will be more easily understood in the process of explaining specific embodiments of the present invention.

[0057]

[0058] Figure 1 is an image of a perovskite solution manufactured in a manufacturing example of the present invention.

[0059] Figure 2 is an SEM image of a perovskite thin film manufactured in an example and comparative example of the present invention.

[0060] Figure 3 is a graph showing the XPS analysis results for perovskite thin films manufactured in examples and comparative examples of the present invention.

[0061]

[0062] Hereinafter, embodiments of the present invention will be described with reference to specific embodiments and the attached drawings. It should be understood that the technology described herein is not limited to specific embodiments, but rather encompasses various modifications, equivalents, and / or alternatives of the embodiments of the present invention. In connection with the description of the drawings, similar reference numerals may be used for similar components.

[0063]

[0064] In this specification, expressions such as “has”, “may have”, “includes”, or “may include” indicate the presence of a feature (e.g., a component such as a number, function, operation, or part), and do not exclude the presence of additional features.

[0065]

[0066] In this specification, expressions such as "A or B," "at least one of A and / or B," or "one or more of A or / and B" can include all possible combinations of the listed items. For example, "A or B," "at least one of A and B," or "at least one of A or B" can all refer to (1) including at least one A, (2) including at least one B, or (3) including both at least one A and at least one B.

[0067]

[0068] The present invention relates to a perovskite solution. The perovskite solution according to one embodiment of the present invention may include a perovskite precursor or a perovskite compound; a compound represented by the following chemical formula 1; and water.

[0069] [Chemical Formula 1]

[0070] RCOOH

[0071] In chemical formula 1, R is hydrogen or a C1-C3 alkyl group.

[0072]

[0073] In one example, the perovskite compound of the perovskite solution according to the present invention may include a compound represented by the following chemical formula 2.

[0074] [Chemical Formula 2]

[0075] ABX3

[0076] In the above chemical formula 2, A is formamidinium, methylammonium, cesium, rubidium, potassium, sodium, lithium, guanidinium, butylammonium, ethylammonium or phenethylammonium, B is lead, tin, germanium, cadmium, zinc or manganese, and X is iodide, bromide, chloride, fluoride, thiocyanate, cyanate, selenocyanate, formate or It's acetate.

[0077]

[0078] In another example, the perovskite precursor compound of the perovskite solution according to the present invention may include at least one selected from among formamidinium bromide (FABr), formamidinium iodide (FAI), methylammonium iodide (MAI), methylammonium bromide (MABr), methylammonium chloride (MACl), and inorganic halogen compounds.

[0079]

[0080] Perovskite compounds are known to have strong solar absorption and a low non-radiative carrier recombination rate, as well as high carrier mobility and the absence of defects that cause non-radiative carrier recombination within the band gap or at deep levels, which increases conversion efficiency. When these perovskite compounds are applied to solar cells, the manufacturing cost is low and thin films can be produced using a solution process. Therefore, perovskite solar cells are currently attracting attention as next-generation thin-film solar cells.

[0081]

[0082] Manufacturing perovskite solar cells using the above perovskite compound through a solution process requires the use of anhydrous solvents, which are expensive and difficult to handle. Non-anhydrous solvents for general mass production may typically contain water as an impurity. However, if water is included in the solvent used to manufacture a perovskite solution, a reaction as shown in Scheme 1 below may occur.

[0083]

[0084] [Reaction Formula 1]

[0085] 4CH3NH3PbI3+ 4H2O → 4[CH3NH3PbI3x H2O] → (CH3NH3)4PbI 6x 2H2O + 3PbI2+ 2H2O

[0086]

[0087] When using a mass production solvent containing water as an impurity as described above, such water may also cause problems for the perovskite precursor compound.

[0088]

[0089] [Reaction Formula 2]

[0090] CH3NH3 + ↔ C3NH2+ H +

[0091]

[0092] In the above reaction formula, MA + (methylammonium + ) has a pKa of 10.6 and H2O has a pKa of 14 to 15, so MA + It acts as an acid when mixed with water. Therefore, H + can be transferred to water, and thus the perovskite A-site material can be decomposed by water.

[0093]

[0094] [Reaction Formula 3]

[0095] 4I - + O2+ 4H + ↔ 2I2+ H2O

[0096] I - + I2↔ I 3-

[0097]

[0098] In addition, the iodide anion contained in the perovskite precursor can be decomposed and evaporated as in the above reaction scheme 3. This can cause cation defects during the formation of the perovskite thin film, which can cause problems such as lowering the efficiency and stability of the solar cell.

[0099]

[0100] The present invention is intended to solve such problems, and the perovskite solution according to the present invention can suppress decomposition of the perovskite compound due to impurities by including a compound represented by compound 1.

[0101]

[0102] [Reaction Formula 4]

[0103] 4CH3NH3PbI3+ 4CHOOH +4H2O → 4CH3NH3PbI3+4CHOO - +4H3O +

[0104]

[0105] The above reaction scheme 4 shows the mechanism for inhibiting the decomposition of the perovskite compound when the compound represented by chemical formula 1 is added. As described above, the perovskite compound formed into the ABX3 structure is converted to the ABX structure instead of the ABX3 structure. x There is a problem of decomposition into H2O hydrate. At this time, when a compound represented by the chemical formula 1 is added, the compound represented by the chemical formula 1 reacts with water to form H3O. + By forming it, the decomposition of the perovskite compound can be suppressed.

[0106]

[0107] As with the perovskite compound, the perovskite solution according to the present invention can prevent problems such as decomposition of the perovskite precursor by including the compound of chemical formula 1.

[0108]

[0109] [Reaction Formula 5]

[0110] HC(NH2)2 + ← C(NH2)2+ CHOOH

[0111] CH3NH3 + ← CH3NH2 + + CHOOH

[0112]

[0113] The above reaction scheme 5 shows the mechanism for inhibiting the decomposition of the perovskite precursor when the compound represented by chemical formula 1 is added. As described above, FAH in the presence of moisture + I - and MAH + I - can be deprotonated. At this time, when HCOOH (carboxylic acid) is added as in reaction scheme 5, the forward reaction is suppressed and the reverse reaction is induced. Through this, the compound represented by chemical formula 1 can suppress the decomposition of the perovskite precursor.

[0114]

[0115] [Reaction Formula 6]

[0116] H + + CO2+ 2I - ← I2+ HCOO -

[0117] H + + CO2+ 3I - ← I3 - + HCOO -

[0118]

[0119] In addition, when HCOOH is added to the perovskite solution, the oxidized iodide can be reduced again as shown in the above reaction formula 6, and oxidation can be suppressed.

[0120]

[0121] In one example of the present invention, the compound represented by Chemical Formula 1 may be HCOOH. When the compound represented by Chemical Formula 1 is HCOOH, R in Chemical Formula 1 may be hydrogen.

[0122]

[0123] In one example, the compound represented by Chemical Formula 1 of the perovskite solution according to the present invention may be included in an amount of 0.5% by volume or more and / or 9.0% by volume or less based on the entire perovskite solution. If the content of the compound represented by Chemical Formula 1 is less than 0.5% by volume with respect to the entire perovskite solution, decomposition of the perovskite compound or perovskite precursor compound due to moisture may not be suppressed, and if it exceeds 9.0% by volume, the compound represented by Chemical Formula 1 may cause precipitation in the solution, making it difficult to apply it to a solution process for forming a perovskite thin film.

[0124]

[0125] In another example, the water of the perovskite solution according to the present invention may be contained in an amount of 50 ppm or more relative to the entire perovskite solution. The water may be an impurity introduced during the process of preparing the perovskite solution, and specifically, may be contained in a mass-produced solvent. The water content may be, for example, 50 ppm or more, 70 ppm or more, 90 ppm or more, 110 ppm or more, 130 ppm or more, or 150 ppm or more, and the upper limit is not particularly limited, but may be, for example, 2000 ppm or less, 1900 ppm or less, or 1800 ppm or less.

[0126]

[0127] In one example of the present invention, the perovskite solution according to the present invention may further include one or more solvents selected from dimethyl sulfoxide (DMSO), dimethylformamide (DMF), N-methylformamide (NMF), gamma-butyrolactone (GBL), N-methyl-2-pyrrolidone (NMP), N-cyclohexyl-2-pyrrolidone (CHP), and N,N-dimethylpropyleneurea (DMPU).

[0128]

[0129] The solvent may not be an anhydrous type solvent as described above, and may be a mass-produced solvent. The criterion for distinguishing an anhydrous type solvent from a mass-produced solvent may be based on the water content of the solvent. For example, a solvent having a water content of less than 50 ppm may be classified as an anhydrous type solvent. In addition, if the water content in the solvent is 50 ppm or more, 70 ppm or more, 90 ppm or more, 110 ppm or more, 130 ppm or more, or 150 ppm or more, it may be classified as a mass-produced solvent. The perovskite solution according to the present invention can increase the production efficiency of perovskite solar cells by using a mass-produced solvent.

[0130]

[0131] The present invention also relates to a method for forming a perovskite thin film. Another embodiment of the present invention includes the steps of forming a hole transport layer on a transparent substrate; coating a perovskite solution on the hole transport layer; and heat-treating the perovskite solution; wherein the perovskite solution includes a perovskite compound, a compound represented by the following chemical formula 1, and water. The method for forming a perovskite thin film can be provided.

[0132] [Chemical Formula 1]

[0133] RCOOH

[0134] In chemical formula 1, R is hydrogen or a C1-C3 alkyl group.

[0135]

[0136] At this time, the compound represented by the above chemical formula 1 may be included in a range of 0.5% by volume or more and / or 9.0% by volume or less based on the entire perovskite solution.

[0137]

[0138] Additionally, the water may be included in an amount of 50 ppm or more relative to the entire perovskite solution.

[0139]

[0140] Meanwhile, the perovskite solution of the perovskite thin film forming method according to the present invention may further include at least one solvent selected from dimethyl sulfoxide (DMSO), dimethylformamide (DMF), N-methylformamide (NMF), gamma-butyrolactone (GBL), N-methyl-2-pyrrolidone (NMP), N-cyclohexyl-2-pyrrolidone (CHP), and N,N-dimethylpropyleneurea (DMPU).

[0141]

[0142] Descriptions of the compound, water, solvent, etc. represented by the above chemical formula 1 are the same as those described above, so they will be omitted.

[0143]

[0144] Hereinafter, preferred examples are presented to aid in understanding the present invention. However, the following examples are provided solely to facilitate a better understanding of the present invention, and the scope of the present invention is not limited by the following examples.

[0145]

[0146] Manufacturing example

[0147] A perovskite solution was prepared using mass-production DMF solvent, not a reagent-grade anhydrous solvent. The perovskite solution was prepared by mixing precursors of perovskite compounds represented by ABX (wherein A is an inorganic precursor such as CsX and / or an organic precursor such as FAX, B is Pb metal, and X is a halide (I, Br, Cl)), and 3 v / v% of HCOOH was added to the perovskite solution as a compound represented by chemical formula 1.

[0148]

[0149] Figure 1 is a photograph of the perovskite solution manufactured in the manufacturing example and the solvent for mass production stored for two weeks. Referring to Figure 1, it can be confirmed that the solvent for mass production without additives shows a darker yellow color than the perovskite solution manufactured in the manufacturing example of the present invention. This is because, as can be confirmed in reaction formulas 1 to 3, I2 or I3 is produced by the water contained in the solvent for mass production. - This is because it is generated. In contrast, in the case of the perovskite solution manufactured in the manufacturing example of the present invention, I2 or I3 - It can be seen that the color of the solution hardly changes even after two weeks from manufacturing because it suppresses the occurrence.

[0150]

[0151] Example

[0152] The lower solar cell used a crystalline silicon solar cell including a first doped layer on a p-type silicon substrate.

[0153]

[0154] A first electrode (ITO) having an average thickness of 20 nm was formed on the above silicon solar cell substrate through physical vapor deposition. NiOx was deposited on the first electrode through a vacuum vapor deposition method, and 200 μl of Me-4PACz [4-(3,6-Dimethyl-9H-carbazol-9-yl)butyl]phosphonic acid was dropped on the NiOx, spin-coated at 3000 rpm for 30 seconds, and heat-treated at 100°C to form a hole transport layer having an average thickness of 20 nm.

[0155]

[0156] Cs manufactured in the following manufacturing example 0.2 FA 0.8 Pb(I 0.8 Br 0.2) 100 ㎕ of a 1.3 M perovskite precursor solution with a composition of 3 was dropped, spin-coated at 5000 rpm for 30 seconds under a nitrogen atmosphere, and then heat-treated at 100°C for 20 minutes to form a perovskite thin film with a final thickness of 700 nm.

[0157]

[0158] A 13 nm thick C60 layer was formed as an electron transport layer on the perovskite thin film, and a 10 nm thick SnO2 layer, which serves as both an ETL and butter, was deposited on the formed electron transport layer using an ALD process. Thereafter, a 70 nm thick top TCO layer was formed by physical vapor deposition, and a 200 nm thick second electrode (Ag) was formed using thermal vapor deposition equipment, thereby manufacturing a perovskite / silicon tandem photoelectric conversion device.

[0159]

[0160] Comparative Example 1

[0161] A tandem element was manufactured in the same manner as in Example 1, except that a reagent-grade anhydrous solvent, not a mass-produced solvent, was used and HCOOH was not added.

[0162]

[0163] Comparative Example 2

[0164] A tandem element was manufactured in the same manner as in Example 1, except that HCOOH was not added to the mass production solvent used in Manufacturing Example 1.

[0165]

[0166] Experimental Example 1

[0167] The moisture content of reagent-grade anhydrous DMF solvent and mass-produced DMF solvent was measured using the Karl Fischer coulometric titration method, and is shown in Table 1 below. Specifically, a moisture measurement solution containing iodide ions is electrolyzed to generate iodine, and then the moisture content can be measured from the amount of electricity consumed in the electrolysis by utilizing the quantitative reaction of iodine with water. Since iodine reacts with water as shown in Equation (1) below, coulometric titration and volumetric titration are possible.

[0168] I2+SO2+3Base+ROH+H2O ⇒ 2Base·HI+Base·HSO4R··(1)

[0169]

[0170]

[0171] Referring to Table 1, it can be seen that the reagent-grade anhydrous DMF solvent showed an average moisture content of 48 ppm, but the mass-produced solvent contained an average moisture content of 354.7 ppm, which is approximately 7 times higher than the anhydrous type solvent.

[0172]

[0173] Experimental Example 2

[0174] The performance of each tandem solar cell manufactured in Examples 1 and 2 and Comparative Examples 1 and 2 was measured and shown in Table 2 below. Specifically, the efficiency of the solar cell was measured using the initial JV curve using a solar simulation device and a JV Keithley device.

[0175]

[0176]

[0177]

[0178] Referring to Table 2 above, it can be confirmed that the electrical performance of the tandem solar cell manufactured in the example of the present invention is very excellent. In particular, it can be seen that the tandem solar cell manufactured in the example of the present invention has a performance level equivalent to that of Comparative Example 1 using a reagent-grade anhydrous solvent in terms of open circuit voltage, fill factor, and power conversion efficiency. On the other hand, in the case of Comparative Example 2, it can be confirmed that the performance of the tandem solar cell of Comparative Example 2 is significantly lower than that of the example even though the same mass production solvent as that of the example was used. Through this, it can be seen that the perovskite solution according to the present invention has a very excellent effect even in a mass production solvent by including the compound represented by Chemical Formula 1.

[0179]

[0180] Experimental Example 3

[0181] The components of the perovskite thin film manufactured in Example and Comparative Example 1 were analyzed by XPS (X-ray photoelectron spectroscopy) and UPS (Ultraviolet photoelectron spectroscopy) using AXIS supra equipment, and the results are shown in Table 3 below.

[0182]

[0183]

[0184]

[0185] Referring to Table 3 above, it can be confirmed that the I content of the perovskite thin film manufactured in the example of the present invention is higher than the I content of the perovskite thin film of Comparative Example 1. As previously discussed, even anhydrous type solvents contain a small amount of water as an impurity, which causes a side reaction that decomposes I.

[0186]

[0187] (Reaction Formula 2) Through the above results, H of the A site is due to the moisture contained in the anhydrous type solvent.+ I which is combined together as it is broken down - The ions are decomposed together, and thus (Reaction Formula 3) the result shows that the I content of the perovskite thin film of Comparative Example 1 is reduced due to the trace amount of moisture contained in the anhydrous type solvent, whereas the example of the present invention in which the compound represented by Chemical Formula 1 is added suppresses the decomposition, and thus has an effect of having a higher I content than Comparative Example 1 using the anhydrous type solvent.

[0188]

[0189] Experimental Example 4

[0190] FIG. 2 is an image of the perovskite thin films manufactured in Comparative Examples 1 and 2 and the Examples, taken with a field emission scanning electron microscope (FE-SEM, JSM-7900F, JEOL). FIG. 2(a) shows Comparative Example 1, FIG. 2(b) shows Comparative Example 2, and FIG. 2(c) shows the Examples, respectively. Referring to FIG. 2, it can be seen that the perovskite thin film of Comparative Example 2, which uses a mass-production solvent, has uneven grain sizes and a very rough surface, compared to Comparative Example 1, which uses an anhydrous type solvent. On the other hand, it can be seen that the perovskite thin film manufactured in the Examples of the present invention has grain size uniformity and surface roughness similar to those of Comparative Example 1, which uses an anhydrous solvent.

[0191]

[0192] Experimental Example 5

[0193] FIG. 3 shows the results of measuring the crystallinity of the perovskite thin films manufactured in Examples, Comparative Examples 1 and 2 using X-ray diffraction analysis (X-ray Diffraction, XRD, D8 ADAVNCE, BRUKER). Referring to FIG. 3, in the case of Comparative Example 2, which used a solvent for mass production, it can be seen that the peak of theta 14.1°, which indicates perovskite crystallinity, is significantly lowered. In contrast, it can be confirmed that the perovskite thin film manufactured in the Examples of the present invention exhibits a peak of almost similar size to that of Comparative Example 1, which used an anhydrous solvent. Therefore, the perovskite solution according to the present invention can maintain a high level of perovskite crystallinity even while using a solvent for mass production by including the compound represented by Chemical Formula 1.

[0194]

[0195] While the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and the attached drawings, but is intended to be defined by the appended claims. Accordingly, those skilled in the art will appreciate that various substitutions, modifications, and alterations may be made without departing from the technical spirit of the present invention as defined in the claims, and such modifications are also within the scope of the present invention.

Claims

1. Perovskite compound or perovskite precursor compound; A compound represented by the following chemical formula 1; and Perovskite solution containing water; [Chemical Formula 1] RCOOH In chemical formula 1, R is hydrogen or a C1-C3 alkyl group.

2. In paragraph 1, The above perovskite compound is a perovskite solution containing a compound represented by the following chemical formula 2: [Chemical Formula 2] ABX3 In the above chemical formula 2, A is formamidinium, methylammonium, cesium, rubidium, potassium, sodium, lithium, guanidinium, butylammonium, ethylammonium or phenethylammonium, B is lead, tin, germanium, cadmium, zinc or manganese, and X is iodide, bromide, chloride, fluoride, thiocyanate, cyanate, selenocyanate, formate or It's acetate.

3. In paragraph 1, The perovskite precursor compound is a perovskite solution comprising at least one selected from among FABr (formamidinium bromide), FAI (formamidinium iodide), MAI (methylammonium iodide), MABr (methylammonium bromide), MACl (methylammonium chloride) and an inorganic halogen compound.

4. In paragraph 1, The compound represented by the above chemical formula 1 is a perovskite solution of HCOOH.

5. In paragraph 1, A perovskite solution in which the compound represented by the above chemical formula 1 is included in an amount of 0.5% by volume or more and / or 9.0% by volume or less based on the entire perovskite solution.

6. In paragraph 1, A perovskite solution in which the above water is contained in an amount of 50 ppm or more relative to the entire perovskite solution.

7. In paragraph 1, A perovskite solution further comprising at least one solvent selected from dimethyl sulfoxide (DMSO), dimethylformamide (DMF), N-methylformamide (NMF), gamma-butyrolactone (GBL), N-methyl-2-pyrrolidone (NMP), N-cyclohexyl-2-pyrrolidone (CHP), and N,N-dimethylpropyleneurea (DMPU).

8. Step of forming a hole transport layer on a transparent substrate; A step of coating a perovskite solution on the hole transport layer; and A step of heat treating the perovskite solution; The above perovskite solution comprises a perovskite compound, a compound represented by the following chemical formula 1, and water. Method for forming perovskite thin films: [Chemical Formula 1] RCOOH In chemical formula 1, R is hydrogen or a C1-C3 alkyl group.

9. In paragraph 8, The compound represented by the above chemical formula 1 is included in an amount of 0.5% by volume or more and / or 9.0% by volume or less based on the entire perovskite solution. Method for forming perovskite thin films.

10. In paragraph 8, The above water is contained in an amount of 50 ppm or more relative to the entire perovskite solution. Method for forming perovskite thin films.

11. In paragraph 8, The above perovskite solution further comprises at least one solvent selected from dimethyl sulfoxide (DMSO), dimethylformamide (DMF), N-methylformamide (NMF), gamma-butyrolactone (GBL), N-methyl-2-pyrrolidone (NMP), N-cyclohexyl-2-pyrrolidone (CHP), and N,N-dimethylpropyleneurea (DMPU). Method for forming perovskite thin films.

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