Perovskite thin film coating method using additive

Abstract

A perovskite thin film coating method using an additive, according to one embodiment of the present disclosure, comprises the steps of: preparing a solution containing a perovskite precursor; adding an additive to the solution; and applying the solution onto a substrate, wherein the additive is an amide-based compound.

Description

Perovskite thin film coating method using additives

[0001] The present invention relates to a method for coating a perovskite thin film using an additive, and more specifically, to a method for manufacturing a perovskite thin film with an increased grain size using an additive.

[0002] The perovskite crystal structure has various physical properties depending on the interactions within the crystal structure, and is being actively studied as a key material for solar cells, with recently studied perovskite solar cells having a peak efficiency exceeding 25%.

[0003] Meanwhile, the perovskite crystal structure is a polycrystalline structure composed of small grains. However, grain boundary defects not only reduce the stability of perovskite, but also quench photocharges, reducing the efficiency of perovskite thin films.

[0004] Additionally, during the fabrication of perovskite films, tiny, deep pores called "pinholes" can form on the film surface. Because pinholes reduce the electrical efficiency of perovskite films, it is crucial to minimize their number during fabrication.

[0005] The present disclosure aims to manufacture a perovskite thin film using an additive.

[0006] A method for coating a perovskite thin film using an additive according to one embodiment of the present disclosure includes the steps of preparing a solution containing a perovskite precursor, adding the additive to the solution, and coating the solution on a substrate, wherein the additive is an amide series compound.

[0007] According to one embodiment of the present disclosure, the additive corresponds to caprolactam.

[0008] According to one embodiment of the present disclosure, the concentration of caprolactam is from 1 wt% to 3 wt%.

[0009] According to one embodiment of the present disclosure, the additive corresponds to valerolactam.

[0010] According to one embodiment of the present disclosure, the additive corresponds to acetamide.

[0011] According to one embodiment of the present disclosure, the solvent of the solution includes dimethylformamide (DMF) and dimethyl sulfoxide (DMSO).

[0012] According to one embodiment of the present disclosure, the method comprises the step of coating a solution on a substrate by shear coating.

[0013] According to one embodiment of the present disclosure, the method further comprises forming a perovskite thin film by annealing the substrate.

[0014] According to one embodiment of the present disclosure, a thin film manufacturing device for manufacturing a perovskite thin film by the above method is provided.

[0015] According to one embodiment of the present disclosure, a perovskite thin film manufactured by the above method is provided.

[0016] By using various embodiments of the present disclosure, it is possible to suppress the formation of pinholes on the surface of a perovskite thin film during manufacture by introducing an additive.

[0017] By using various embodiments of the present disclosure, the efficiency of a perovskite thin film can be increased by increasing the grain size within the perovskite thin film.

[0018] The effects of the present disclosure are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs (hereinafter referred to as “ordinary skilled person”) from the description of the claims.

[0019] Figures 1 and 2 are drawings comparing the degree of pinhole occurrence in a perovskite thin film depending on the presence or absence of an additive in the solution.

[0020] Figure 3 is a diagram comparing the phase transformation speed of a perovskite thin film depending on the presence or absence of an additive in the solution.

[0021] Figures 4 and 5 are drawings comparing grain sizes in perovskite thin films depending on the presence or absence of additives in the solution.

[0022] Figure 6 is a diagram comparing the results of TCSPC (Time-correlated Single Photon Counting) spectrum measurements of perovskite thin film devices with and without additives in the solution.

[0023] FIG. 7 is a diagram showing the difference in current density in a large-area perovskite device depending on the presence or absence of a caprolactam additive according to one embodiment of the present disclosure.

[0024] FIG. 8 is a diagram showing the difference in conversion efficiency (PCE) of a perovskite thin film device depending on the concentration of a caprolactam additive according to one embodiment of the present disclosure.

[0025] Hereinafter, specific details for implementing the present disclosure will be described in detail with reference to the attached drawings. However, in the following description, specific descriptions of widely known functions or configurations will be omitted if they may unnecessarily obscure the gist of the present disclosure.

[0026] Throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0027] The term "about" used throughout this specification is used to encompass the tolerance when there is a tolerance.

[0028] Throughout this specification, the term "at least one" in a Markush format expression means including one or more selected from the group consisting of components described in the Markush format expression.

[0029] Throughout this specification, references to “A and / or B” mean “A, or B, or A and B.”

[0030] Throughout this specification, “perovskite” or “PE” means a material having a perovskite crystal structure, which may have various perovskite crystal structures in addition to the ABX3 crystal structure.

[0031] Throughout this specification, a “device” may be a device having a photoelectric conversion function or an electro-optical conversion function, for example, a solar cell.

[0032] Throughout this specification, the term "halide", "halogen", "halide" or "halo" means a material or composition containing a halogen atom belonging to Group 17 of the Periodic Table in the form of a functional group, which may include, for example, chlorine, bromine, fluorine or iodine compounds.

[0033] Throughout this specification, "precursor" may mean a precursor or reactant used to prepare a perovskite, and is not limited to a specific material.

[0034] Throughout this specification, the term “coating” is used to encompass any wet process utilizing a solvent.

[0035] A method for coating a perovskite thin film using an additive may be initiated by preparing a solution containing a solvent and a perovskite precursor. In one embodiment, the perovskite precursor contained in the solution may correspond to a 95:5 molar ratio mixture of CH(NH2)2PbI3 (formamidinium lead iodide, FAPbI3) and CH3NH3PbBr3 (methylammonium lead bromide, MAPbBr3). The solvent may correspond to, but is not limited to, dimethylformamide (DMF) and dimethyl sulfoxide (DMSO).

[0036] Thereafter, an additive may be added to the solution containing the perovskite precursor. The additive may correspond to an amide series compound. In one embodiment, the additive added to the solution may correspond to a cyclic amide compound. In one embodiment, the additive added to the solution may correspond to caprolactam, which is a cyclic amide compound of the chemical formula (CH2)5C(O)NH. At this time, the concentration of caprolactam added to the solution may correspond to 1 wt% to 3 wt%. In another embodiment, the additive may correspond to valerolactam (VL). In yet another embodiment, the additive may correspond to acetamide. Additionally, specific electrical characteristic differences according to the type of additive are as shown in Table 1 below. In the table and drawings, the mark "X" means that the corresponding material is not included.

[0037]

[0038] Solvent type Precursor type Additive type Voc(V) Jsc(mA / cm2) FF(%) PCE(%) DMF:DMSO (8:1, v / v)(FAPbI3) 0.95 (MAPbBr3)0.05 Caprolactam X1.13123.49577.420.574 Valerolactam 1.13623.67878.821.178 Caprolactam 1.15322.65879.821.767 Acetamide 1.14423.63278.721.278

[0039] Amide-based additives can increase the grain size of perovskite films by slowing down the phase transformation rate of perovskite. Furthermore, the NH and C=O bonding groups of amide-based compounds can act as passivators in the perovskite films, thereby reducing surface defects in the perovskite films.

[0040] The prepared solution can be coated onto a substrate. In one embodiment, the solution can be coated onto the substrate using shear coating. This coating method not only forms a uniform film when forming a perovskite film on the substrate, but also suppresses the formation of pinholes. After the solution is coated onto the substrate, the substrate is annealed, thereby forming a perovskite film on the substrate.

[0041] Figures 1 and 2 are drawings comparing the degree of pinhole formation in perovskite thin films depending on the presence or absence of additives in the solution. Specifically, Figure 1 corresponds to a general photographed image of a perovskite thin film, and Figure 2 corresponds to an image of a perovskite thin film taken with a scanning electron microscope (SEM). In Figures 1 and 2, it can be confirmed that pinholes are hardly formed in the perovskite thin film manufactured with the addition of an additive, compared to the perovskite thin film manufactured without the addition of an additive.

[0042]

[0043] Related drawings Solvent type Precursor type Additive type Fig. 1 and Fig. 2 No additive DMF: DMSO (8:1, v / v) (FAPbI3) 0.95(MAPbBr3) 0.05 Caprolactam with X-1 and X-2 additives

[0044] Figure 3 is a diagram comparing the phase transformation speed of perovskite thin films with and without additives in the solution. Compared to a perovskite thin film manufactured without additives, it can be confirmed that the phase transformation speed in the perovskite thin film manufactured with additives is delayed.

[0045]

[0046] Related drawing Solvent type Precursor type Additive type Figure 3 No additive DMF: DMSO (8:1, v / v) (FAPbI3) 0.95 (MAPbBr3) 0.05 X-3 additive added caprolactam

[0047] FIGS. 4 and 5 are diagrams comparing grain sizes in perovskite thin films with and without additives in the solution. Specifically, FIG. 4 corresponds to a surface image of a perovskite thin film photographed with an optical microscope, and FIG. 5 corresponds to a surface image of a perovskite thin film photographed with a scanning electron microscope. In FIGS. 4 and 5, it can be confirmed that the grain size is larger in the perovskite thin film prepared with the additive added due to a delayed phase transformation speed compared to the perovskite thin film prepared without the additive added. Specifically, as a result of comparing the grain sizes by measuring the longest length in each grain in FIG. 5, it was confirmed that the grain size of the perovskite thin film prepared without the additive added was 963±305 nm, whereas the grain size of the perovskite thin film prepared with the additive added increased to 1167±230 nm.

[0048]

[0049] Related drawings Solvent type Precursor type Additive type Fig. 4 and Fig. 5 No additive DMF: DMSO (8:1, v / v) (FAPbI3) 0.95 (MAPbBr3) 0.05Caprolactam with X-4 and 5 additives

[0050] Figure 6 is a diagram comparing the results of Time-correlated Single Photon Counting (TCSPC) spectrum measurements of perovskite thin film devices with and without additives in the solution. In the case of perovskite thin films with additives, the lifetime of excited carriers increases, and non-luminescent recombination is suppressed by reducing defects, resulting in an increase in normalized intensity compared to perovskite thin films without additives.

[0051]

[0052] Related Drawings Solvent Type Precursor Type Additive Type Fig. 6 Ref DMF: DMSO (8:1, v / v) (FAPbI3) 0.95 (MAPbBr3) 0.05 X6 CL caprolactam

[0053] Figure 7 is a diagram showing the difference in current density in a large-area perovskite thin film device (module) with or without a caprolactam additive according to one embodiment of the present disclosure. Specifically, the large-area perovskite module measured in Figure 7 is 7x7 cm. 2 substrate, area 25 cm 2 , corresponds to a 10-line connection module.

[0054]

[0055] Related drawings Solvent type Precursor type Additive type Figure 7 w / o CLDMF:DMSO(8:1, v / v)(FAPbI3) 0.95 (MAPbBr3) 0.05 X-degree 7 w / CL caprolactam

[0056] In Figure 7, it can be confirmed that the current density as a function of voltage of the perovskite film with 2% caprolactam additive is higher than that of the perovskite film without caprolactam additive. Additionally, the specific electrical characteristics differences depending on the presence or absence of the caprolactam additive are shown in Table 7 below.

[0057]

[0058] Related Drawing V OC (V)J SC (mA / cm 2 )FFPCE (%) 7 w / o CL11.922.1577.4719.82 7 w / CL11.782.1880.2520.58

[0059] As shown in Table 7, it can be confirmed that the short-circuit current (mA / cm2), Fill Factor (FF) (%), and conversion efficiency (%) of the perovskite thin film with the caprolactam additive are higher than those of the perovskite thin film without the caprolactam additive. Therefore, the perovskite thin film manufactured according to one embodiment of the present disclosure can be utilized for a photovoltaic device.

[0060] FIG. 8 is a diagram illustrating the difference in conversion efficiency (PCE) of a perovskite thin film depending on the concentration of a caprolactam additive according to one embodiment of the present disclosure. In FIG. 8, it can be seen that the conversion efficiency of the perovskite thin film increases overall as the concentration of caprolactam increases up to 3%. Additionally, specific differences in electrical characteristics depending on the concentration of the caprolactam additive are shown in Table 8 below.

[0061]

[0062] Related Drawing V OC (V)J SC (mA / cm 2 )FFPCE (%) also 8 REF1.113(1.089)22.844(22.822)0.782(0.755)19.874(18.765) also 8 CL1Caprolactam 1wt%1.125(1.103)23.150(22.820)0.766(0.766)19.949(19.292) also 8 CL2Caprolactam 2wt%1.123(1.105)22.961(23.347)0.790(0.776)20.377(20.024) also 8 CL3Caprolactam 2wt%1.143(1.112)23.111(23.037)0.799(0.772)21.100(19.788)

[0063] The conditions used in the experiment are as follows.

[0064] 1) Current-voltage characteristics: Using an artificial sun device (ORIEL class A solar simulator, Newport, model 91195A) and a source-meter (source-meter, Kethley, model 2420), the light of the AM1.5G spectrum was irradiated through the artificial sun device with an irradiance of 1,000 W / ㎡, and then the voltage was applied in both directions (Reverse / Forward) and the current was measured, and the open circuit voltage (V) was measured through this. OC ), short-circuit current density (J SC ) and fill factor (FF) were calculated.

[0065] 2) Power conversion efficiency (PCE): The final power conversion efficiency was obtained by multiplying the values ​​of open circuit voltage, short circuit current density, and fill factor calculated from the current-voltage characteristics.

[0066] 3) Stability: Stability was evaluated by inputting the measured PCE value into the following calculation formula.

[0067] Calculation formula = (η1 / η0) x 100

[0068] In the calculation formula, η0 represents the initial photoelectric conversion efficiency of the perovskite optical device immediately after the stability test begins, and η1 represents the photoelectric conversion efficiency measured after a certain period of time after the same perovskite optical device is continuously irradiated with the AM1.5G spectrum and 1 Sun light intensity of an artificial solar device.

[0069] 4) Maximum power point tracking (MPPT): In the case of the light irradiation stability results shown in Figs. 4 and 5, the voltage indicating the maximum output was continuously detected and tracked, thereby showing the relative maximum output value that changes over time.

[0070] The preceding description of the present disclosure is provided to enable any person skilled in the art to make or use the present disclosure. Various modifications to the present disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to various modifications without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the examples described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0071] While the present disclosure has been described in connection with certain embodiments herein, it should be understood that various modifications and variations can be made without departing from the scope of the present disclosure, which would be apparent to those skilled in the art. Furthermore, such modifications and variations are intended to fall within the scope of the claims appended to this specification.

Claims

1. In a perovskite thin film coating method using an additive, A step of preparing a solution containing a perovskite precursor; A step of adding an additive to the above solution; and Comprising a step of coating the above solution on a substrate, A perovskite thin film coating method wherein the above additive corresponds to caprolactam.

2. In a perovskite thin film coating method using an additive, A step of preparing a solution containing a perovskite precursor; A step of adding an additive to the above solution; and Comprising a step of coating the above solution on a substrate, A perovskite thin film coating method, wherein the above additive corresponds to valerolactam.

3. In a perovskite thin film coating method using an additive, A step of preparing a solution containing a perovskite precursor; A step of adding an additive to the above solution; and Comprising a step of coating the above solution on a substrate, The above additive corresponds to acetamide, a perovskite thin film coating method.

4. In paragraph 1, A perovskite thin film coating method, wherein the concentration of the caprolactam is 1 wt% to 3 wt%.

5. In paragraph 1, A method for coating a perovskite thin film, wherein the solvent of the above solution includes dimethylformamide and dimethyl sulfoxide.

6. In paragraph 1, The step of coating the above solution on the substrate is: A perovskite thin film coating method comprising a step of coating the solution on the substrate by shear coating.

7. In paragraph 1, A method for coating a perovskite thin film, further comprising a step of forming a perovskite thin film by annealing the substrate.

8. A thin film manufacturing device for manufacturing a perovskite thin film by the method according to Article 1.

9. A perovskite thin film manufactured by the method according to paragraph 1.

10. In a perovskite thin film coating method using an additive, A step of preparing a solution containing a perovskite precursor; A step of adding an additive to the above solution; and Comprising a step of coating the above solution on a substrate, A perovskite thin film coating method wherein the above additive corresponds to an amide series compound.

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