Method for manufacturing perovskite solar cells

Abstract

The objective is to provide a method for manufacturing perovskite solar cells that can improve power generation efficiency. [Solution] The method for manufacturing a perovskite solar cell of the present invention comprises a carrier transport layer deposition step of depositing a carrier transport layer on the surface of an electrode-equipped substrate, and a photoelectric conversion layer deposition step of depositing a photoelectric conversion layer on the surface of the carrier transport layer, wherein between the carrier transport layer deposition step and the photoelectric conversion layer deposition step, the product of ultraviolet irradiance and irradiation time is 1800 mJ / cm² on the surface of the carrier transport layer. 2 More than 3000mJ / cm 2 The invention is further characterized by comprising a hydrophilization treatment step in which ultraviolet light is irradiated in the following manner.

Description

[Technical Field]

[0001] This invention relates to a method for manufacturing perovskite solar cells. [Background technology]

[0002] In recent years, the emergence of perovskite solar cells has further heightened expectations for next-generation solar cells. Various technologies have been developed for the manufacturing of perovskite solar cells. For example, a method for manufacturing a perovskite solar cell is known, comprising the steps of: a) treating the hole transport layer of a laminate in which a substrate layer, a first electrode layer, and a hole transport layer containing a metal oxide are sequentially stacked, by oxidizing the metal oxide by a) oxidizing agent, b) treating with ultraviolet light and ozone, c) treating with oxygen plasma, or d) treating with nitrogen dioxide gas (step S1); and sequentially stacking a perovskite layer, an electron transport layer, and a second electrode layer on the hole transport layer of the laminate (step S2) (Patent Document 1). Furthermore, a method for manufacturing a solar cell is known, comprising forming a second cell having a second photoelectric conversion layer containing a second photoelectric conversion material having a second band gap, sequentially forming a polycrystalline silicon layer, a second charge transport layer, a transparent conductive layer, and a first charge transport layer on the second photoelectric conversion layer, and forming a first cell having a first photoelectric conversion layer containing a first photoelectric conversion material having a first band gap not equal to the second band gap, wherein the second charge transport layer is formed by thermal deposition, atomic layer deposition, rapid plasma deposition, or solution deposition (Patent Document 2). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Special Publication No. 2023-538996 [Patent Document 2] Japanese Patent Publication No. 2024-028171 [Overview of the project] [Problems that the invention aims to solve]

[0004] Conventional methods for manufacturing perovskite solar cells require the ability to produce perovskite solar cells with improved power generation efficiency. Specifically, the inability to uniformly form a perovskite layer on the surface of the hole transport layer may prevent the production of perovskite solar cells with improved power generation efficiency.

[0005] This invention has been made in view of these points, and its object is to provide a method for manufacturing a perovskite solar cell that can improve power generation efficiency. [Means for solving the problem]

[0006] To solve the above problems, the present invention provides a method for manufacturing a perovskite solar cell comprising: a carrier transport layer deposition step of depositing a carrier transport layer on the surface of an electrode-equipped substrate; and a photoelectric conversion layer deposition step of depositing a photoelectric conversion layer on the surface of the carrier transport layer, wherein between the carrier transport layer deposition step and the photoelectric conversion layer deposition step, the product of ultraviolet irradiance and irradiation time is 1800 mJ / cm² on the surface of the carrier transport layer. 2 More than 3000mJ / cm 2 The invention is further characterized by comprising a hydrophilization treatment step in which ultraviolet light is irradiated in the following manner. [Effects of the Invention]

[0007] According to the present invention, power generation efficiency can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] (a) to (e) are flowcharts illustrating the essential steps of the manufacturing method for a perovskite solar cell according to the embodiment. [Figure 2] This figure shows microscope images of the perovskite layer for each cumulative illuminance in Examples 1 and 2 and Comparative Examples 1 and 2. [Figure 3]This table shows the power generation efficiency for each cumulative illuminance of the solar cells of Examples 1 and 2 and Comparative Examples 1 to 3, as well as the difference in ionization potential between the perovskite layer and the hole transport layer. [Modes for carrying out the invention]

[0009] The following describes a method for manufacturing a perovskite solar cell according to the embodiment. Figures 1(a) to 1(e) are flowcharts that schematically show the main steps of the method for manufacturing a perovskite solar cell according to the embodiment.

[0010] In the manufacturing method according to this embodiment, first, a substrate preparation and cleaning process is performed as shown in Figure 1(a). Specifically, first, alkali-free glass is used as the glass substrate, and ITO (Indium Tin Oxide) is deposited on the surface of the glass substrate by sputtering. The ITO is then processed into an arbitrary pattern by lithography to prepare a glass substrate 2 with ITO (electrodes). Next, the glass substrate 2 with ITO is subjected to wet cleaning, which is ultrasonic cleaning in 1-propanol and then in ethanol in sequence. Then, using a UV ozone generator, the surface of the glass substrate 2 with ITO is subjected to dry cleaning, which is performed with an ultraviolet irradiance of 10 mW / cm². 2 Perform a 10-minute UV irradiation treatment.

[0011] Next, as shown in Figure 1(b), a hole transport layer deposition process (carrier transport layer deposition process) is performed. Specifically, first, a hole transport layer precursor ink is prepared by dissolving 4.5 mg / mL of PTAA (poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]) in 1-Chrolobenzen. Next, the hole transport layer precursor ink is dropped onto the surface of the ITO-coated glass substrate 2 by spin coating and coated at 2000 rpm for 40 seconds. Then, it is heated and dried on a hot plate at 100°C for 10 minutes. This deposits the hole transport layer (HTL) 4, which is the carrier transport layer.

[0012] Subsequently, a hydrophilic treatment step is performed as shown in FIG. 1(c). Specifically, in order to hydrophilize the surface of the hole transport layer 4, using a UV ozone generator, ultraviolet irradiation treatment is performed on the surface of the hole transport layer 4 for 180 seconds to 300 seconds at an ultraviolet illuminance of 10 mW / cm 2 Thereby, a hydrophilic treatment is performed by irradiating ultraviolet rays so that the integrated illuminance (the product of the ultraviolet illuminance and the irradiation time) is 1800 mJ / cm 2 or more and 3000 mJ / cm 2 or less.

[0013] Subsequently, a photoelectric conversion layer film formation step is performed as shown in FIG. 1(d). Specifically, first, a perovskite precursor ink is prepared. A mixture of DMF (N,N-dimethylformamide) and DMSO (Dimethyl sulfoxide) is used as the solvent, and lead iodide, cesium iodide, formamidine hydroiodide, and methylamine hydroiodide are added at 1.0 M as the solute, and dissolved by performing a heat treatment at 150° C for 10 minutes. Thereby, a perovskite precursor ink (precursor solution) is produced. Next, by the spin coating method, the perovskite precursor ink is dropped onto the surface of the hole transport layer 4 on the glass substrate 2 with ITO after the hydrophilic treatment, and coating is performed at 800 rpm for 10 seconds, and further coating is performed at 4000 rpm for 20 seconds. At this time, in order to promote the formation of perovskite crystal nuclei, before the end of the coating by the spin coating method, as a poor solvent treatment, 1-Chlorobezene is dropped onto the surface of the coating film on the rotating substrate 2. Next, after the rotation is completed, heating is performed at 120° C for 60 minutes on a hot plate. Thereby, a film of CsFAMAPbI3 is formed as the perovskite layer (PVK: Perovskite Layer) 6 which is the photoelectric conversion layer. [[ID=~]] [[ID=~]]

[0014] [[ID=~]] In this embodiment, the precursor solution (perovskite precursor ink) is applied by the spin coating method. However, as the method for applying the precursor solution in the present invention is not particularly limited as long as it can uniformly apply the precursor solution to the surface of the carrier transport layer, such as the hole transport layer. Any method can be used to apply the precursor solution. In addition to the spin coating method, for example, an inkjet method, a spray method, a die coating method, etc. may also be used.

[0015] Subsequently, as shown in FIG. 1(e), an electron transport layer film formation step (carrier transport layer film formation step) is performed. Specifically, first, a PCBM precursor ink in which 12.0 g / L of PCBM ([6,6]-Phenyl-C61-Butylic Acid Methyl Ester) is dissolved in 1-Chlorobezene is prepared. Next, by the spin coating method, the PCBM precursor ink is dropped onto the surface of the perovskite layer 6 on the glass substrate 2 with ITO, and coating is performed at 8000 rpm for 30 seconds. Next, heat drying is performed on a hot plate at 100° C. for 10 minutes. Thereby, a film of PCBM is formed. Next, a BCP precursor ink in which 1.0 g / L of BCP (Bathocuproine) is dissolved in ultra-dehydrated 2-Propanol is prepared. Next, by the spin coating method, the BCP precursor ink is dropped onto the surface of the PCBM film on the substrate 2, and coating is performed at 4000 rpm for 30 seconds. Thereby, a laminated film of PCBM and BCP is formed as the electron transport layer (ETL: Electron Transport Layer) 8 which is the carrier transport layer.

[0016] Subsequently, although not shown, a removal step is performed. Specifically, in order to remove unnecessary portions of the hole transport layer 4, the perovskite layer 6, and the electron transport layer 8 formed on the entire surface of the substrate 2, trimming is performed using a UV laser processing machine at a laser wavelength of 355 nm, a laser output of 1.5 W, a scanning speed of 1500 mm / sec, and a frequency of 80 kHz.

[0017] Subsequently, although not shown, an electrode evaporation step is performed. Specifically, as the counter electrode, a silver evaporation film with a thickness of 100 nm is formed. At this time, the silver evaporation film is formed at 1.0×10-3 Film formation is carried out by thermal evaporation under a high vacuum of less than Pa. Thus, a cell of a perovskite solar cell is manufactured.

[0018] In the method for manufacturing a perovskite solar cell according to the embodiment, between the hole transport layer film formation step and the photoelectric conversion layer film formation step, on the surface of the hole transport layer 4, the integrated illuminance (the product of the ultraviolet illuminance and the irradiation time) is 1800 mJ / cm 2 or more and 3000 mJ / cm 2 or less, a hydrophilic treatment of irradiating ultraviolet rays is performed. As a result, in the photoelectric conversion layer film formation step, the perovskite precursor ink is applied to the surface of the hole transport layer 4 where the contact angle of the perovskite precursor ink is reduced by reducing the surface tension in the hydrophilic treatment, and the perovskite layer 6 can be formed. Therefore, the perovskite layer 6 can be uniformly formed over the entire surface of the hole transport layer 4. Further, an increase in the ionization potential difference between the perovskite layer 6 and the hole transport layer 4 due to the irradiation of ultraviolet rays to the hole transport layer 4 can be suppressed. Accordingly, the power generation efficiency of the perovskite solar cell can be improved.

Example

[0019] Hereinafter, the method for manufacturing a perovskite solar cell according to the embodiment will be described more specifically with reference to examples and comparative examples. <null>

[0020] <null> [Example 1] An example of the method for manufacturing a perovskite solar cell according to the above-described embodiment was implemented. At this time, in the hydrophilic treatment step, using a UV ozone generator, ultraviolet ray irradiation treatment was performed on the surface of the hole transport layer 4 at an ultraviolet illuminance of 10 mW / cm 2 and for 180 seconds. As a result, a hydrophilic treatment of irradiating ultraviolet rays was performed so that the integrated illuminance (the product of the ultraviolet illuminance and the irradiation time) became 1800 mJ / cm 2 2 In this way, by implementing an example of the method for manufacturing a perovskite solar cell according to the embodiment, a cell of a perovskite solar cell was manufactured.

[0021] [Example 2 and Comparative Examples 1 to 3] In Example 2 and Comparative Examples 1 and 2, during the hydrophilization treatment process, the surface of the hole transport layer 4 was subjected to an ultraviolet irradiance of 10 mW / cm², respectively. 2 By performing UV irradiation treatment for 300 seconds, 30 seconds, and 60 seconds, the cumulative illuminance for each was 3000 mJ / cm². 2 300 mJ / cm² 2 , and 600 mJ / cm 2 In Comparative Example 3, a perovskite solar cell was manufactured by following the same manufacturing method as in Example 1, except that a hydrophilization treatment was performed by irradiating with ultraviolet light to achieve the desired result.

[0022] [evaluation] IV measurements were performed on the perovskite solar cell cells of Examples 1 and 2 and Comparative Examples 1 to 3. For this measurement, the power generation performance of the solar cell cells was assessed by covering the cells with a shadow mask having an opening smaller than the effective power generation area, and then using a solar simulator (Seric XI-05A1V2-L) to simulate sunlight of 1 SUN (1000 W / m²). 2 Under these conditions, a source meter (Keithley Model 2401) was used to sweep back and forth, and the current (current density J [mA / cm²]) at each voltage was measured. 2 The value of ]) was measured to obtain the power generation efficiency [%]. In addition, the surface of the perovskite layer of each solar cell was photographed with a microscope. Figure 2 shows the microscope images of the perovskite layer for each cumulative illuminance of Examples 1 and 2 and Comparative Examples 1 and 2. Furthermore, the ionization potential of the perovskite layer (PVK) and hole transport layer (HTL) of the solar cells in Examples 1 and 2 and Comparative Examples 1 to 3 was measured using the AC-2 atmospheric photoelectron yield spectrometer manufactured by RIKEN KEKI Co., Ltd., and the difference in ionization potential between the perovskite layer and the hole transport layer was determined. Figure 3 is a table showing the power generation efficiency and the difference in ionization potential between the perovskite layer and the hole transport layer for each cumulative illuminance of the solar cells in Examples 1 and 2 and Comparative Examples 1 to 3.

[0023] As shown in Figure 3, the solar cells of Examples 1 and 2 and Comparative Examples 1 to 3 had an integrated illuminance (product of ultraviolet irradiance and irradiation time) of 1800 mJ / cm². 2 More than 3000mJ / cm 2 The power generation efficiency increased in the following cases. As can be seen from the microscope image in Figure 2 and Figure 3, this is thought to be because the occurrence of cracks during the deposition of the perovskite layer was suppressed, and the increase in the ionization potential difference between the perovskite layer and the hole transport layer was suppressed. On the other hand, when the cumulative illuminance was 1800 mJ / cm² 2 When the value was less than 3000 mJ / cm², the power generation efficiency did not increase significantly. This is thought to be due to cracking during the deposition of the perovskite layer, as can be seen from the microscope image in Figure 2. Also, when the cumulative illuminance was 3000 mJ / cm², the power generation efficiency did not increase significantly. 2 When the value exceeds a certain point, it was suggested that power generation efficiency tends to decrease. This is thought to be due to an increase in the ionization potential difference between the perovskite layer and the hole transport layer.

[0024] Although embodiments of the method for manufacturing a perovskite solar cell according to the present invention have been described in detail above, the present invention is not limited to the embodiments described above, and various design modifications can be made without departing from the spirit of the invention as described in the claims. [Explanation of Symbols]

[0025] 2: Glass substrate with ITO, 4: Hole transport layer, 6: Perovskite layer, 8: Electron transport layer

Claims

[Claim 1] A carrier transport layer deposition process in which a carrier transport layer is deposited on the surface of an electrode-equipped substrate, The process includes a photoelectric conversion layer deposition step of depositing a photoelectric conversion layer on the surface of the carrier transport layer, Between the carrier transport layer deposition process and the photoelectric conversion layer deposition process, the product of ultraviolet irradiance and irradiation time is 1800 mJ / cm² on the surface of the carrier transport layer. ２ More than 3000mJ / cm ２ A method for manufacturing a perovskite solar cell, further comprising a hydrophilization treatment step of irradiating with ultraviolet light in the following manner.

Images