Method for producing perovskite-based inks

Abstract

A method for producing a perovskite-based ink, the method comprising the steps of: 3-y Br y (I) (wherein y is a number in the range of 0 to 0.2, preferably 0.05 to 0.1), (a) dissolving lead iodide (PbI) in at least one organic solvent selected from dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), γ-butyrolactone (GBL), γ-valerolactone (GVL) or a mixture thereof, preferably dimethyl sulfoxide (DMSO), dimethyl formamide (DMF) or a mixture thereof, to obtain a first solution; and (b) adding cesium iodide (CsI) and a compound represented by the general formula (II): R to a part of the first solution obtained in the step (a). x H 4-x (c) dissolving at least one ammonium salt represented by the general formula (III): R NI(II) (wherein R represents a linear or branched C1-C4 alkyl group, preferably a methyl group, and x is an integer ranging from 2 to 4, preferably 2) in a part of the first solution obtained in step (a) to obtain a second solution; and x H 4-x (d) mixing the second solution obtained in step (b) with the third solution obtained in step (c) to obtain a perovskite-based ink, wherein in step (d), the molar ratio of the at least one ammonium salt represented by general formula (II) to the at least one ammonium salt represented by general formula (III) is in the range of 0:100 to 50:50. The perovskite-based ink can be advantageously used in optoelectronic applications, particularly in perovskite-based photovoltaic cells (or solar cells), light-emitting diodes (LEDs), X-ray sensors, and photodetectors.

Description

[Technical Field]

[0001] The present invention relates to a method for making perovskite-based inks.

[0002] More specifically, the present invention provides a method for preparing a perovskite-based ink, wherein the perovskite has the following general formula (I): CsPbI 3-y Br y (I) (wherein y is a number within the range of 0 to 0.2, preferably within the range of 0.05 to 0.1) The present invention relates to a method for producing a perovskite precursor solution, which contains cesium iodide, lead iodide, at least one ammonium salt represented by general formula (II) described later, and at least one ammonium salt represented by general formula (III) described later, in which the at least one ammonium salt represented by general formula (II) and the at least one ammonium salt represented by general formula (III) are used in a molar ratio within a range of 0:100 to 50:50.

[0003] The perovskite-based inks can be advantageously used in optoelectronic applications, particularly in perovskite photovoltaic cells (or solar cells), light emitting diodes (LEDs), X-ray sensors and photodetectors.

[0004] The present invention also relates to a method for producing a perovskite-based film, comprising the steps of (i) depositing a perovskite-based ink obtained by the method that is the subject of the present invention onto a substrate to form a film, and (ii) subjecting the substrate to a heat treatment (annealing) at a temperature in the range of 120°C to 190°C, preferably in the range of 135°C to 185°C. [Background technology]

[0005] In recent years, the need to reduce carbon dioxide (CO2) emissions for sustainable development has made photovoltaics (or solar cells) a promising solution as an alternative energy source to fossil fuels. However, the current market is dominated by low-cost, efficient, but highly energy-intensive solutions to energy-intensive manufacturing processes. For this reason, research is focused on developing new semiconductor materials that are efficient, low-cost, and have a reduced environmental impact.

[0006] Particularly in the last decade, new semiconductor materials based on hybrid organic-inorganic compounds, called hybrid perovskites, have emerged. Hybrid perovskites, more commonly identified in the class of organic-inorganic hybrid perovskites and historically represented by lead methylammonium triiodide (CH3NH3PbI3), possess excellent optoelectronic properties, among them a high absorption coefficient, the possibility to easily tune the band gap, tolerance to structural defects, and long diffusion lengths of charge carriers.

[0007] Photovoltaic cells (or solar cells) based on organic-inorganic hybrid perovskite have shown exponential growth in terms of their power conversion efficiency (PCE), reaching a value of 25.6% for single-junction photovoltaic cells (or solar cells), surpassing more mature photovoltaic (or solar) technologies. These photovoltaic cells (or solar cells) based on organic-inorganic hybrid perovskite are formed by a series of overlapping thin layers, with the organic-inorganic perovskite interposed between two charge transport layers: a layer based on a hole transport material (hole transport layer - HTL) and a layer based on an electron transport material (electron transport layer - ETL). The opposite ends of these photovoltaic cells (or solar cells) based on organic-inorganic hybrid perovskite have a glass substrate coated with a transparent conductive oxide on one side and a metal contact, known as the back contact, on the other side.

[0008] Another class of perovskites suitable for use in optoelectronic devices and photovoltaic (or solar) cells is the inorganic perovskites, in which organic moieties are replaced by inorganic elements such as cesium (Cs). These perovskites exhibit higher thermal stability compared to hybrid perovskites, primarily due to the absence of volatile and hygroscopic organic cations. Among the main materials in this class, cesium lead triiodide (CsPbI3) has been developed, which, when used in the photoactive layer of a so-called "normal" configuration photovoltaic (or solar) cell, as appropriately modified by the insertion of additional layers, can reach energy conversion efficiency values ​​[power conversion efficiency - (PCE)] of more than 20%. However, a strong limitation to the use of this material is the high annealing temperature required for the photoactive layer containing it. This not only makes the process energy-intensive, but also limits the application field of cesium lead triiodide (CsPbI3) in photovoltaic (or solar) cells. Indeed, a layer based on an electron transport material (electron transport layer - ETL) placed under a photoactive layer containing cesium lead triiodide (CsPbI3) must withstand the temperatures of 210°C most commonly used for the thermal treatment (annealing) of said photoactive layer without degradation.

[0009] Photovoltaic cells (or solar cells) are divided into two categories: forward or "nip" configuration cells, and inverted or "pin" configuration cells.

[0010] A photovoltaic cell in a forward or "nip" configuration is one in which a perovskite-containing photoactive layer is below a layer based on an electron transport material (electron transport layer - ETL) and above that a layer based on a hole transport material (hole transport layer - HTL), whereas in an inverted or "pin" configuration, a layer based on a hole transport material (hole transport layer - HTL) is below the perovskite-containing photoactive layer and above that a layer based on an electron transport material (electron transport layer - ETL).

[0011] In general, photovoltaic cells (or solar cells) with a photoactive layer containing cesium lead triiodide (CsPbI3) reported in the literature are cells with a forward type, or "nip" configuration, and more specifically comprise the following layers: (i) a glass substrate coated with a layer of transparent conductive oxide (Transparent Conductive Oxide - TCO), (ii) a layer based on an electron transport material (Electron Transport Layer - ETL), generally a compact layer of titanium dioxide (c-TiO2), (iii) optionally a mesoporous titanium dioxide (TiO2) scaffold intended to increase the interfacial area with the perovskite by increasing the electron collection efficiency, (iv) a photoactive layer containing cesium lead triiodide (CsPbI3), (v) a layer based on a hole transport material (Hole Transport Layer - HTL), generally spiro-OMeTAD (N 2 ,N 2 ,N 2’ ,N 2’ ,N 7 ,N 7 ,N 7’ ,N 7’ -octakis(4-methoxyphenyl)-9,9'-spirobi[9H-fluorene]-2,2',7,7'-tetramine), (vi) a metal contact known as the back contact, which constitutes the cathode, typically a metal layer of gold, silver, or copper. These photovoltaic cells (or solar cells) are typically encapsulated in glass to protect them from atmospheric agents and for use in practical conditions.

[0012] Cesium lead triiodide (CsPbI3) has four crystalline phases divided into two main groups. The first group is the so-called black phase, which includes the cubic phase designated by the Greek letter α, the tetragonal phase designated by the Greek letter β, and the orthorhombic phase designated by the Greek letter γ. These phases have a bandgap of approximately 1.7 eV and are suitable for use as active materials in perovskite photovoltaic (or solar) cells. For this reason, they are often referred to as photoactive phases. The second group instead includes the so-called yellow phase designated by the Greek letter δ, which belongs to the orthorhombic crystal system and has a bandgap of 2.95 eV. Due to its very high bandgap, it is not used in perovskite photovoltaic (or solar) cells.

[0013] Methods for depositing one of the above cesium lead triiodide (CsPbI3) photoactive layers are known in the art.

[0014] Typically, the deposition process of cesium lead triiodide (CsPbI3) is performed by spin-coating a precursor solution of CsPbI3, which is prepared by dissolving lead iodide (PbI2) and cesium iodide (CsI) in an organic solvent, such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO). After deposition, the resulting thin film must be heat-treated (annealed) to remove the solvent and allow nucleation of CsPbI3 crystal grains. To obtain higher-performance photovoltaic cells (or solar cells), hydrogen iodide (HI) is often added to the mixture of lead iodide (PbI2) and cesium iodide (CsI), which reacts with dimethylformamide (DMF) via hydrolysis to produce dimethylammonium iodide (DMAI). Adding this compound to the mixture or synthesizing it in situ in appropriate amounts allows for the deposition and stabilization of the β-phase of cesium lead triiodide (CsPbI3), achieving efficiencies greater than 16% in forward-conducting cells. The resulting thin film is then subjected to a thermal treatment (annealing) at 210 °C for 5 minutes, which converts the dissolved precursors into dimethylammonium lead triiodide (DMAPbI3) and lead cesium hexaiodide (Cs4PbI6), low-dimensional perovskites. Subsequent high-temperature thermal treatment (annealing) combines these two compounds to form cesium lead triiodide (CsPbI3) and removes the gaseous dimethylammonium iodide (DMAI) (see Scheme 1 below).

[0015] Scheme 1 CsI+PbI2+xDMAI → DMAPbI3+Cs4PbI6→ CsPbI3+DMAI

[0016] Details of the above process can be found, for example, in the following articles: Whang Y. et al., "Angewante Chemie" (2019), Vol. 58, Issue 46, pp. 16691-16696 and Wang H. et al., "Nano Energy" (2021), Vol. 84, pp. 105881.

[0017] As mentioned above, perovskite photovoltaic cells (or solar cells) having a photoactive layer containing cesium lead triiodide (CsPbI3) are cells with a forward or "nip" configuration, and their hole transport material-based layer (hole transport layer - HTL) is generally spiro-OMeTAD (N 2 ,N 2 ,N 2’ ,N 2’ ,N 7 ,N 7 ,N 7’ ,N 7’ The electron transport material-based layer (electron transport layer - ETL) is typically a compact layer of titanium dioxide (c-TiO2). The choice of compact layer of titanium dioxide (c-TiO2) as the electron carrier is due, among other reasons, to its ability to withstand temperatures of 210 °C without degradation of its optoelectronic properties.

[0018] However, the need for energy-intensive processes, such as annealing at high temperatures (i.e., 210 °C), to stabilize the photoactive phase of cesium lead triiodide (CsPbI3) limits the use of these perovskites in industrial applications or in applications where lower process temperatures are required, such as flexible electronics. Furthermore, it should be noted that in perovskite photovoltaic cells (or solar cells) with a photoactive layer containing cesium lead triiodide (CsPbI3) in the normal or "nip" configuration, the most commonly used electron-transporting material-based layer (electron transport layer—ETL) is titanium dioxide (TiO2), which requires annealing at 450 °C to stabilize the phase suitable for electron transport. This process is particularly costly and difficult to apply industrially.

[0019] As a result, to overcome the aforementioned drawbacks, developing a method for depositing cesium lead triiodide (CsPbI3) layers that can stabilize the black phase at lower temperatures opens the door to the use of alternative materials. These are alternative electron-transporting materials, such as tin oxide (SnO2), when considering the normal, or "nip," configuration, and hole-transporting materials, such as [2-(3,6-dimethoxy-9H-carbazol-9-yl)ethyl]phosphonic acid (MeO-2PACz), when considering the inverted, or "pin," configuration. These materials can be processed at low temperatures, allowing for greater use in industrial and other applications, such as flexible electronics. Summary of the Invention

[0020] The Applicant therefore set himself the problem of finding a method for producing a perovskite-based ink, in which the perovskite is cesium lead triiodide (CsPbI), and which is able to stabilize its photoactive phase at temperatures lower than those normally used.

[0021] The present applicant has discovered a method for producing a perovskite-based ink, in which the perovskite is cesium lead triiodide (CsPbI3), the CsPbI3 precursor solution contains cesium iodide, lead iodide, dimethylammonium iodide (DMAI), and dimethylammonium bromide (DMABr), and the DMAI and DMABr are used in a molar ratio of 0:100 to 50:50. The perovskite-based thin film obtained by this method can be subjected to a thermal treatment (annealing) at temperatures below 210°C to obtain the photoactive phase of the perovskite, thereby enabling more versatile use in industrial fields and other applications, such as flexible electronics. The perovskite-based ink can be advantageously used in optoelectronic applications, particularly perovskite-based photovoltaic cells (or solar cells), light-emitting diodes (LEDs), X-ray sensors, and photodetectors.

[0022] It is therefore an object of the present invention to provide a method for preparing a perovskite-based ink, wherein the perovskite is represented by the following general formula (I): CsPbI 3-y Br y (I) (wherein y is a number within the range of 0 to 0.2, preferably within the range of 0.05 to 0.1) is expressed as (a) dissolving lead iodide (PbI) in at least one organic solvent selected from dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), γ-butyrolactone (GBL), γ-valerolactone (GVL) or a mixture thereof, preferably dimethyl sulfoxide (DMSO), dimethyl formamide (DMF) or a mixture thereof, to obtain a first solution; (b) adding cesium iodide (CsI) and a compound represented by the following general formula (II): R x H 4-x NI (II) (wherein R represents a linear or branched C1 to C4 alkyl group, preferably a methyl group, and x represents an integer of 2 to 4, preferably 2). and at least one ammonium salt represented by the formula (I) to obtain a second solution; (c) adding cesium iodide (CsI) and a compound represented by the following general formula (III): R x H 4-x NBr(III) (wherein R represents a linear or branched C1 to C4 alkyl group, preferably a methyl group, and x represents an integer of 2 to 4, preferably 2). and at least one ammonium salt represented by the formula (I) to obtain a third solution; (d) mixing the second solution obtained in step (b) with the third solution obtained in step (c) to obtain a perovskite-based ink; Including, In the step (d), the molar ratio of the at least one ammonium salt represented by general formula (II) to the at least one ammonium salt represented by general formula (III) is within the range of 0:100 to 50:50. [Brief explanation of the drawings]

[0023] [Figure 1] Figure 1 shows a cross-sectional view of a "nip" perovskite photovoltaic cell (or solar cell). [Figure 2] 1 shows the X-ray diffraction pattern of the film. [Figure 3] 1 shows the absorption spectrum of the film in the visible range. [Figure 4] 1 shows the photoluminescence spectrum of the film. [Figure 5] 1 shows the X-ray diffraction pattern of the film. [Figure 6] 1 shows the absorption spectrum of the film in the visible range. [Figure 7] 1 shows the photoluminescence spectrum of the film. [Figure 8] 1 shows the X-ray diffraction pattern of the film. [Figure 9] 1 shows the absorption spectrum of the film in the visible range. [Figure 10] 1 shows the photoluminescence spectrum of the film. [Figure 11] 1 shows the X-ray diffraction pattern of the film. [Figure 12] 1 shows the absorption spectrum of the film in the visible range. [Figure 13] 1 shows the photoluminescence spectrum of the film. DETAILED DESCRIPTION OF THE INVENTION

[0024] For purposes of this specification and the appended claims, numerical range definitions always include the extremes unless otherwise specified.

[0025] For purposes of this specification and the appended claims, the term "comprising" also includes the terms "consisting essentially of" or "consisting of."

[0026] According to a preferred embodiment of the present invention, the at least one ammonium salt represented by general formula (II) is dimethylammonium iodide (DMAI).

[0027] According to a preferred embodiment of the present invention, the at least one ammonium salt represented by general formula (III) is dimethylammonium bromide (DMABr).

[0028] According to a preferred embodiment of the present invention, the above step (a) can be carried out at a temperature in the range of 30°C to 80°C, preferably in the range of 40°C to 70°C.

[0029] According to a preferred embodiment of the present invention, the step (a) can be carried out for a period of time ranging from 1 hour to 12 hours, preferably from 4 hours to 11 hours.

[0030] According to a preferred embodiment of the present invention, the above step (b) can be carried out at a temperature in the range of 15°C to 35°C, preferably in the range of 20°C to 30°C, more preferably at room temperature (25°C).

[0031] According to a preferred embodiment of the present invention, the step (b) can be carried out for a period of time ranging from 5 minutes to 2 hours, preferably from 10 minutes to 1 hour.

[0032] According to a preferred embodiment of the present invention, the above step (c) can be carried out at a temperature within a range of 15°C to 35°C, preferably within a range of 20°C to 30°C, more preferably at room temperature (25°C).

[0033] According to a preferred embodiment of the present invention, the step (c) can be carried out for a period of time ranging from 5 minutes to 2 hours, preferably from 10 minutes to 1 hour.

[0034] According to a preferred embodiment of the present invention, the above step (d) can be carried out at a temperature within a range of 15°C to 35°C, preferably within a range of 20°C to 30°C, more preferably at room temperature (25°C).

[0035] According to a preferred embodiment of the present invention, the step (d) can be carried out for a period of time ranging from 5 minutes to 2 hours, preferably from 8 minutes to 1 hour.

[0036] The present invention also relates to a method for producing a perovskite film, comprising the steps of (i) depositing a perovskite-based ink obtained by the method object of the present invention onto a substrate to form a film, and (ii) subjecting said substrate to a heat treatment (annealing) at a temperature in the range of 120°C to 190°C, preferably in the range of 135°C to 185°C.

[0037] Deposition of the perovskite-based ink onto a substrate can be carried out according to deposition techniques known in the art, such as spin coating, slot-die coating, blade coating, screen printing, spray coating, inkjet printing, gravure printing, spray pyrolysis.

[0038] As mentioned above, the perovskite-based inks obtained by the method object of the present invention can be advantageously used in perovskite photovoltaic (or solar) cells.

[0039] It is therefore a further object of the present invention to provide a method for producing a perovskite photovoltaic cell (or solar cell), comprising the steps of: (a1) providing a glass substrate coated with a transparent conductive oxide layer (Transparent Conductive Oxide - TCO) (anode) [e.g., a layer of indium tin oxide (Indium Tin Oxide - ITO) or fluorine-doped tin oxide (SnO2:F) (Fluorine-doped Tin Oxide - FTO)]; (b1) depositing a layer based on an electron transport material (electron transport layer - ETL), for example a compact layer of titanium dioxide (c-TiO2), onto the photoactive layer obtained in step (a1) above; (c1) optionally depositing a mesoporous oxide-based layer (scaffold) on the electron transport material-based layer (electron transport layer - ETL) obtained in step (b1) above; (d1) depositing a perovskite-based ink obtained by the method object of the present invention onto the layer based on an electron transport material obtained in step (b1) above (electron transport layer - ETL) or onto the layer based on a mesoporous oxide obtained in step (c1) above (scaffold), thereby obtaining a photoactive layer; (e1) On the photoactive layer obtained in step (d1) above, a layer based on a hole transport material (hole transport layer - HTL) (e.g., spiro-OMeTAD(N 2 ,N 2 ,N 2’ ,N 2’ ,N 7 ,N 7 ,N 7’,N 7’ -octakis(4-methoxyphenyl)-9,9'-spirobi[9H-fluorene]-2,2',7,7'-tetramine); (f1) depositing a metal contact, known as the back contact, constituting the cathode, on the layer based on a hole transport material (hole transport layer - HTL) obtained in step (e1) above; wherein step (d1) is carried out at a temperature in the range of 120°C to 190°C, preferably in the range of 135°C to 185°C.

[0040] For purposes of the above method, steps (b1), (c1), (d1) and (e1) can be carried out according to deposition techniques known in the art, such as spin coating, slot die coating, blade coating, screen printing, spray coating, inkjet printing, gravure printing, spray pyrolysis.

[0041] For the purposes of the above method, step (f1) can be carried out according to techniques known in the art, such as evaporation, sputtering, electron beam assisted deposition, sputtering, spin coating, gravure printing, flexographic printing, slot die coating.

[0042] The present invention will now be described in more detail through embodiments with reference to FIG. 1 described below.

[0043] In particular, Figure 1 shows a cross-sectional view of a perovskite photovoltaic cell (or solar cell) (1) in a forward configuration, or "nip," comprising the following layers: The photoactive layer comprises a glass substrate (7) coated with a layer of a transparent conductive oxide (transparent conductive oxide - TCO) (anode) [for example, indium tin oxide (indium tin oxide - ITO) or fluorine-doped tin oxide (SnO2:F) (fluorine-doped tin oxide - FTO)] (2), a layer based on an electron transport material (electron transport layer - ETL) [for example, a compact layer of titanium dioxide (c-TiO2)] (3), optionally a scaffold of mesoporous titanium dioxide (TiO2) (not represented in Figure 1) intended to increase the interfacial area with the perovskite by increasing the electron collection efficiency, a photoactive layer (4) comprising the perovskite-based ink obtained by the method object of the present invention, and a layer based on a hole transport material (hole transport layer - HTL) [for example, spiro-OMeTAD (N 2 ,N 2 ,N 2’ ,N 2’ ,N 7 ,N 7 ,N 7’ ,N 7’ -octakis(4-methoxyphenyl)-9,9'-spirobi[9H-fluorene]-2,2',7,7'-tetramine layer] (5), and a metal contact known as the back contact [e.g., a metal layer of gold, silver, or aluminum] (6) that constitutes the cathode.

[0044] In order to better understand and to practice the present invention, some illustrative and non-limiting examples thereof are given below.

[0045] In the following examples, for simplicity, the term solar cell will be used, which should be understood to have the same meaning as photovoltaic cell. [Example]

[0046] Example 1 (Comparative Example) Preparation of perovskite-based inks containing dimethylammonium iodide (DMAI) and dimethylammonium bromide (DMABr) in a 75:25 molar ratio 655 mg of lead iodide (TCI-Tokyo Chemical Industry Co., Ltd.) (1.421 mol) and 1.4764 mL of a 4:1 (v / v) mixture of dimethylformamide (DMF) (Merck) and dimethyl sulfoxide (DMSO) (Merck) were placed in a 4 mL vial. The resulting solution was stirred on a heating plate at 60 °C for 10 hours to obtain a first solution. Subsequently, 112 mg of cesium iodide (TCI-Tokyo Chemical Industry Co., Ltd.) (0.431 mol) and 74.6 mg of dimethylammonium iodide (DMAI) (Merck) (0.431 mol), which had been previously weighed in a 1.5 mL vial, and 479 μL of the first solution were placed in the 4 mL vial. The resulting solution was stirred on a plate at room temperature (25 °C) for 30 minutes to obtain a second solution. Next, 237 mg of cesium iodide (TCI - Tokyo Chemical Industry Co., Ltd.) (0.912 mol) and 80.5 mg of dimethylammonium bromide (DMABr) (Greatcell Solar Materials, Inc.) (0.639 mol), which had been previously weighed into a 1.5 mL vial, and 1.0136 mL of the first solution were added to a 4 mL vial. The resulting solution was stirred on a plate at room temperature (25 °C) for 30 minutes to obtain a third solution. Next, 267 μL of the second solution containing dimethylammonium iodide (DMAI) and 127.2 μL of the third solution containing dimethylammonium bromide (DMABr) were added to the 4 mL vial. The entire mixture was mixed using a magnetic stirrer at room temperature (25 °C) for 10 minutes to obtain a perovskite-based ink containing dimethylammonium iodide (DMAI) and dimethylammonium bromide (DMABr) in a 75:25 molar ratio.

[0047] Example 2 (present invention) Preparation of perovskite-based inks containing dimethylammonium iodide (DMAI) and dimethylammonium bromide (DMABr) in a 50:50 molar ratio 655 mg of lead iodide (TCI-Tokyo Chemical Industry Co., Ltd.) (1.421 mol) and 1.4764 mL of a 4:1 (v / v) mixture of dimethylformamide (DMF) (Merck) and dimethyl sulfoxide (DMSO) (Merck) were placed in a 4 mL vial. The resulting solution was stirred on a heating plate at 60 °C for 10 hours to obtain a first solution. Subsequently, 112 mg of cesium iodide (TCI-Tokyo Chemical Industry Co., Ltd.) (0.431 mol) and 74.6 mg of dimethylammonium iodide (DMAI) (Merck) (0.431 mol), which had been previously weighed into a 1.5 mL vial, and 479 μL of the first solution were placed in the 4 mL vial. The resulting solution was stirred on a plate at room temperature (25 °C) for 30 minutes to obtain a second solution. Next, 237 mg of cesium iodide (TCI - Tokyo Chemical Industry Co., Ltd.) (0.912 mol) and 80.5 mg of dimethylammonium bromide (DMABr) (Greatcell Solar Materials, Inc.) (0.639 mol), which had been weighed out in a 1.5 mL vial, and 1.0136 mL of the first solution were added to a 4 mL vial. The resulting solution was stirred on a plate at room temperature (25 °C) for 30 minutes to obtain a third solution. Next, 161.6 μL of the second solution containing dimethylammonium iodide (DMAI) and 230.9 μL of the third solution containing dimethylammonium bromide (DMABr) were added to the 4 mL vial. The entire mixture was mixed using a magnetic stirrer at room temperature (25 °C) for 10 minutes to obtain a perovskite-based ink containing dimethylammonium iodide (DMAI) and dimethylammonium bromide (DMABr) in a 50:50 molar ratio.

[0048] Example 3 (present invention) Preparation of perovskite-based inks containing dimethylammonium iodide (DMAI) and dimethylammonium bromide (DMABr) in a molar ratio of 25:75 655 mg of lead iodide (TCI-Tokyo Chemical Industry Co., Ltd.) (1.421 mol) and 1.4764 mL of a 4:1 (v / v) mixture of dimethylformamide (DMF) (Merck) and dimethyl sulfoxide (DMSO) (Merck) were placed in a 4 mL vial. The resulting solution was stirred on a heating plate at 60 °C for 10 hours to obtain a first solution. Subsequently, 112 mg of cesium iodide (TCI-Tokyo Chemical Industry Co., Ltd.) (0.431 mol) and 74.6 mg of dimethylammonium iodide (DMAI) (Merck) (0.431 mol), which had been previously weighed in a 1.5 mL vial, and 479 μL of the first solution were placed in a 4 mL vial. The resulting solution was stirred on a plate at room temperature (25 °C) for 30 minutes to obtain a second solution. Next, 237 mg of cesium iodide (TCI - Tokyo Chemical Industry Co., Ltd.) (0.912 mol) and 80.5 mg of dimethylammonium bromide (DMABr) (Greatcell Solar Materials, Inc.) (0.639 mol), which had been weighed out in a 1.5 mL vial, were added to a 4 mL vial along with 1.0136 mL of the first solution. The resulting solution was stirred on a plate at room temperature (25 °C) for 30 minutes to obtain a third solution. Next, 73.6 μL of the second solution containing dimethylammonium iodide (DMAI) and 315.4 μL of the third solution containing dimethylammonium bromide (DMABr) were added to the 4 mL vial. The entire mixture was mixed using a magnetic stirrer at room temperature (25 °C) for 10 minutes to obtain a perovskite-based ink containing dimethylammonium iodide (DMAI) and dimethylammonium bromide (DMABr) in a molar ratio of 25:75.

[0049] Example 4 (present invention) Preparation of perovskite-based inks containing dimethylammonium iodide (DMAI) and dimethylammonium bromide (DMABr) in a molar ratio of 0:100 655 mg of lead iodide (TCI-Tokyo Chemical Industry Co., Ltd.) (1.421 mol) and 1.4764 mL of a 4:1 (v / v) mixture of dimethylformamide (DMF) (Merck) and dimethyl sulfoxide (DMSO) (Merck) were placed in a 4 mL vial. The resulting solution was stirred on a heating plate at 60 °C for 10 hours to obtain a first solution. Subsequently, 237 mg of cesium iodide (TCI-Tokyo Chemical Industry Co., Ltd.) (0.912 mol) and 80.5 mg of dimethylammonium bromide (DMABr) (Greatcell Solar Materials) (0.639 mol), which had been previously weighed in a 1.5 mL vial, and 1.0136 mL of the first solution were added to the 4 mL vial. The resulting solution was stirred on a plate at room temperature (25°C) for 30 minutes to obtain a perovskite-based ink containing dimethylammonium iodide (DMAI) and dimethylammonium bromide (DMABr) in a molar ratio of 0:100.

[0050] Example 5 (Comparative Example) Preparation of perovskite-based inks containing dimethylammonium iodide (DMAI) and dimethylammonium chloride (DMACl) in a molar ratio of 0:100 100 mg of lead iodide (TCI-Tokyo Chemical Industry Co., Ltd.) (0.2254 mol) and 0.241 mL of a 4:1 (v / v) mixture of dimethylformamide (DMF) (Merck) and dimethyl sulfoxide (DMSO) (Merck) were placed in a 4 mL vial. The resulting solution was stirred on a heating plate at 60 °C for 10 hours to obtain a first solution. Subsequently, 50 mg of cesium iodide (TCI-Tokyo Chemical Industry Co., Ltd.) (0.192 mol) and 15.7 mg of dimethylammonium chloride (Merck) (0.192 mol), both previously weighed in a 1.5 mL vial, and 0.2138 mL of the first solution were placed in a 4 mL vial. The resulting solution was stirred on a plate at room temperature (25 °C) for 30 minutes.

[0051] During stirring, precipitation of a yellow solid was observed, making it impossible to use the solution as an ink.

[0052] Example 6 (Comparative Example) Preparation of perovskite film using the ink obtained in Example 1 For this purpose, glass substrates were previously subjected to a cleaning procedure consisting of manual wiping with a lint-free cloth soaked in a detergent diluted with deionized water. The substrates were then rinsed with deionized water. The substrates were then thoroughly cleaned in the following successive ways: (i) deionized water + detergent (followed by manual drying with a lint-free cloth), (ii) distilled water (followed by manual drying with a lint-free cloth), (iii) acetone (Aldrich), and (iv) ultrasonic baths in isopropanol (Aldrich). In particular, the substrates were placed in a beaker containing the solvent and then placed in an ultrasonic bath maintained at room temperature (25 °C) for 20 minutes. After treatments (iii) and (iv), the substrates were dried with a compressed nitrogen stream. The substrates were then further cleaned by treatment in an ozone device (UV Ozone Cleaning System - PSD from Novasca) immediately before proceeding to the next step.

[0053] The substrate thus treated was ready for the deposition of a perovskite-based ink. For this purpose, 90 mL of the ink obtained in Example 1 was deposited by spin coating carried out at a rotation speed of 3,000 rpm (acceleration of 1,000 rpm / s) for 30 seconds. The whole was subjected to a heat treatment (annealing) at 180°C for the following times: 1 minute, 5 minutes, and 10 minutes. The thickness of the resulting film was found to be 450 nm.

[0054] The thickness was measured by scanning atomic force microscopy using an atomic force microscope ("TriA AFM" - APE Research) in contact mode, measuring 20 × 20 μm. 2 The area was measured with a resolution of 256 x 256 pixels.

[0055] Figure 2 [angle (2θ) in degrees (°) is shown on the horizontal axis, and counts in arbitrary units (au) on the vertical axis] shows X-ray diffraction patterns acquired using a Brucker D2 Phaser diffractometer with Cu Kα (λ = 1.5406 Å) radiation, acquired in 0.02° steps with 1 second acquisition time for each step, for different annealing times. The diffraction pattern obtained after 10 minutes of annealing highlights the presence of precursors in the final material, indicating an incomplete reaction.

[0056] Visible absorption spectra (520 nm to 800 nm) of the resulting films were also obtained in transmittance using a Perkin Elmer λ1050+ spectrophotometer, a double beam and double monochromator equipped with a double deuterium and tungsten lamp, a double monochromator, and a PbS Peltier photomultiplier.

[0057] Figure 3 [wavelength in nanometers (nm) is shown on the horizontal axis and absorbance in arbitrary units (au) is shown on the vertical axis] shows the absorption spectrum of the obtained film in the visible range (520 nm to 800 nm).

[0058] Photoluminescence spectra of the resulting films were also acquired. These spectra were acquired using the optical setup reported in Pica G. et al., "Structural Dynamics" (2022), Vol. 9, 011101, doi: 10.1063 / 4.0000134, consisting of a PicoQuant laser excitation source at 470 nm, an interferometer, and a single-photon detector. Measurements were performed by exciting the sample with a laser beam. The photoluminescence emitted by the sample was collimated at the input of the interferometer through a lens system, and the signal was guided to the single-photon detector through an optical fiber. Photoluminescence spectra were acquired in the wavelength range from 600 nm to 850 nm.

[0059] FIG. 4 [wavelength in nanometers (nm) is shown on the horizontal axis and intensity in arbitrary units (au) is shown on the vertical axis] shows the photoluminescence spectrum (600 nm to 850 nm) of the resulting film.

[0060] Example 7 (Invention) Preparation of perovskite film using the ink obtained in Example 2 For this purpose, 90 ml of the ink obtained in Example 2 were deposited by spin coating, carried out for 30 seconds at a rotation speed of 3,000 rpm (acceleration of 1,000 rpm / s), on a glass substrate previously subjected to the cleaning procedure described in Example 6. The whole was subjected to a thermal treatment (annealing) at 180° C. for the following times: 1 minute, 5 minutes, and 10 minutes. The thickness of the film obtained was found to be 450 nm.

[0061] The thickness was measured as reported in Example 6.

[0062] Figure 5 [angle (2θ) in degrees (°) is shown on the horizontal axis and counts in arbitrary units (au) is shown on the vertical axis] shows the X-ray diffraction patterns for different heat treatment (annealing) times obtained as described in Example 6. The diffraction pattern obtained after 10 minutes of heat treatment (annealing) shows the limited presence of the precursor in the final material, confirming the correct deposition of the material.

[0063] The absorption spectrum of the resulting film in the visible range (520 nm to 800 nm) was also obtained as described in Example 6. Figure 6 (wavelength in nanometers (nm) is shown on the horizontal axis and absorbance in arbitrary units (au) is obtained on the vertical axis) shows the absorption spectrum of the resulting film in the visible range (520 nm to 800 nm).

[0064] Photoluminescence spectra of the resulting films were also obtained as described in Example 6. Figure 7 [wavelength in nanometers (nm) is shown on the horizontal axis and intensity in arbitrary units (au) is shown on the vertical axis] shows the photoluminescence spectra (600 nm to 850 nm) of the resulting films.

[0065] Example 8 (Invention) Preparation of perovskite film using the ink obtained in Example 3 For this purpose, 90 ml of the ink obtained in Example 3 were deposited by spin coating, carried out for 30 seconds at a rotation speed of 3,000 rpm (acceleration of 1,000 rpm / s), on a glass substrate previously subjected to the cleaning procedure described in Example 6. The whole was subjected to a thermal treatment (annealing) at 180° C. for the following times: 1 minute, 5 minutes, and 10 minutes. The thickness of the film obtained was found to be 450 nm.

[0066] The thickness was measured as described in Example 6.

[0067] Figure 8 [angle (2θ) in degrees (°) is shown on the horizontal axis and counts in arbitrary units (au) is shown on the vertical axis] shows X-ray diffraction patterns for different heat treatment (annealing) times obtained as described in Example 6. The diffraction pattern obtained after 10 minutes of heat treatment (annealing) shows the limited presence of precursors in the final material, confirming the correct deposition of the material.

[0068] The absorption spectrum of the resulting film in the visible range (520 nm to 800 nm) was also obtained as described in Example 6. Figure 9 (wavelength in nanometers (nm) is shown on the horizontal axis and absorbance in arbitrary units (au) is shown on the vertical axis) shows the absorption spectrum of the resulting film in the visible range (520 nm to 800 nm).

[0069] Photoluminescence spectra of the resulting films were also obtained as described in Example 6. Figure 10 (wavelength in nanometers (nm) is shown on the horizontal axis and intensity in arbitrary units (au) is shown on the vertical axis) shows the photoluminescence spectra (600 nm to 850 nm) of the resulting films.

[0070] Example 9 (Invention) Preparation of perovskite film using the ink obtained in Example 4 For this purpose, 90 ml of the ink obtained in Example 4 were deposited by spin coating, carried out for 30 seconds at a rotation speed of 3,000 rpm (acceleration of 1,000 rpm / s), on a glass substrate previously subjected to the cleaning procedure described in Example 6. The whole was subjected to a thermal treatment (annealing) at 180° C. for the following times: 1 minute, 5 minutes, and 10 minutes. The thickness of the film obtained was found to be 450 nm.

[0071] The thickness was measured as described in Example 6.

[0072] Figure 11 (angle (2θ) in degrees (°) is shown on the horizontal axis and counts in arbitrary units (au) is shown on the vertical axis) shows X-ray diffraction patterns for different heat treatment (annealing) times obtained as described in Example 6. The diffraction pattern obtained after 10 minutes of heat treatment (annealing) shows the limited presence of precursors in the final material, confirming the correct deposition of the material.

[0073] The absorption spectrum of the resulting film in the visible range (520 nm to 800 nm) was also obtained as described in Example 6. Figure 12 (wavelength in nanometers (nm) is shown on the horizontal axis and absorbance in arbitrary units (au) is shown on the vertical axis) shows the absorption spectrum of the resulting film in the visible range (520 nm to 800 nm).

[0074] Photoluminescence spectra of the resulting films were also obtained as described in Example 6. Figure 13 (wavelength in nanometers (nm) is shown on the horizontal axis and intensity in arbitrary units (au) is shown on the vertical axis) shows the photoluminescence spectra (600 nm to 850 nm) of the resulting films.

[0075] Example 10 (Comparative Example) Fabrication of perovskite solar cells using the ink obtained in Example 1 For this purpose, perovskite solar cells were prepared on patterned glass substrates (dimensions 29 × 29 × 1.6 mm, sheet resistance 15 Ω / cm) coated with FTO [fluorine-doped tin oxide (SnO:F) (Yingkou Shangneng Photoelectric Material Co. Ltd)], which had previously been subjected to a cleaning procedure consisting of manual rubbing with a lint-free cloth soaked in a cleaning agent diluted with deionized water. 2 ). The substrate was then rinsed with deionized water. The substrate was then thoroughly cleaned by the following successive methods: (i) deionized water + detergent (followed by manual drying with a lint-free cloth), (ii) distilled water (followed by manual drying with a lint-free cloth), (iii) acetone (Aldrich), and (iv) ultrasonic bath in isopropanol (Aldrich). In particular, the substrate was placed in a beaker containing the solvent, placed in an ultrasonic bath, and treated for 20 minutes at room temperature (25°C). After treatments (iii) and (iv), the substrate was dried with a compressed nitrogen stream.

[0076] The substrate was then further cleaned by treatment in an ozone device (UV ozone cleaning system - PSD from Novascan) just before proceeding to the next step.

[0077] The substrate thus treated was ready for the deposition of a titanium dioxide (TiO2)-based electron transport layer (ETL). For this purpose, a solution of titanium(IV) diisopropoxide (Merck) (0.6 mL) and anhydrous isopropanol (Merck) (9 mL) was prepared, and this solution was deposited by spray pyrolysis at 450 °C. After the deposition was completed, the whole was subjected to a heat treatment (annealing) at 450 °C for 1 h, followed by cooling to room temperature (25 °C). The thickness of the compact titanium dioxide layer (c-TiO2) was found to be 40 nm.

[0078] A mesoporous titanium dioxide (TiO2) layer was deposited on the obtained titanium dioxide (TiO2) layer as follows: To this end, a suspension of mesoporous titanium dioxide (TiO2) nanoparticles (Merck) (1 g) in absolute ethanol (Merck) (8 mL) was prepared. This solution was deposited by spin coating, carried out at a rotation speed of 2,000 rpm (acceleration of 2,000 rpm / s) for 20 seconds. The thickness of the mesoporous titanium dioxide (TiO2) layer was found to be 150 nm. After the deposition was completed, the whole was subjected to a thermal treatment (annealing) at 500 °C for 20 minutes, followed by cleaning again by treatment in an ozone device (UV ozone cleaning system - PSD from Novascan) just before proceeding to the next step.

[0079] Onto the mesoporous titanium dioxide (TiO) layer thus obtained, a perovskite layer was deposited, i.e., 90 μl of the ink obtained in Example 1, by spin-coating carried out at a rotation speed of 3,000 rpm (acceleration of 1,000 rpm / s) for 30 seconds, and the whole was subjected to a heat treatment (annealing) at 180° C. for 10 minutes. The thickness of the perovskite layer was found to be 450 nm.

[0080] On top of the resulting perovskite layer, a layer based on a hole transport material (hole transport layer - HTL) was deposited. For this purpose, 78 mg of spiro-OMeTAD (N 2 ,N 2 ,N 2’ ,N 2’ ,N 7 ,N 7 ,N 7’ ,N 7’9H-octakis(4-methoxyphenyl)-9,9'-spirobi[9H-fluorene]-2,2',7,7'-tetramine (Merck) was dissolved in 1 ml of chlorobenzene (Merck). 31 μl of 4-tert-butylpyridine (Merck), 19 μl of a 517 mg / ml stock solution of lithium bis(trifluoromethylsulfonyl)imide (Alfa Aesar) in acetonitrile (Merck), and 14 μl of a 376 mg / ml stock solution of cobalt bis(trifluoromethylsulfonyl)imide (Alfa Aesar) in acetonitrile (Merck) were added to the resulting solution. The resulting solution was deposited by spin coating at a rotation speed of 4,000 rpm (acceleration rate of 2,000 rpm / s) for 40 seconds. After the deposition was complete, the whole was left at room temperature (25 °C) for 12 hours. The thickness of the layer based on hole transport material (hole transport layer - HTL) was found to be 100 nm.

[0081] On top of the hole transport material-based layer (hole transport layer - HTL), a 0.16 cm 2 The device area was appropriately masked to obtain an active area of ​​1000 nm, and a gold (Au) back contact (cathode) was deposited by vacuum evaporation to a thickness of 80 nm.

[0082] The cathode deposition was carried out in a standard vacuum deposition chamber (Aldrich) containing a substrate and an evaporation chamber equipped with a heating element containing 10 gold (Au) shots (1 mm to 3 mm in diameter). The deposition process was carried out under vacuum at a rate of approximately 1 × 10 -6 The deposition was performed at a pressure of 100 bar. The gold (Au) condensed on the unmasked parts of the device after deposition.

[0083] The thickness was measured by scanning atomic force microscopy using an atomic force microscope ("TriA AFM" - APE Research) in contact mode, measuring 20 × 20 μm. 2 The area was measured with a resolution of 256 x 256 pixels.

[0084] The electrical characteristics of the perovskite solar cell thus obtained were evaluated at room temperature (25°C) and 30% humidity (30% RH). The photocurrent was classified as AM1.5G and was 1 sun (100 mW / cm). 2 The solar cell was measured by exposing it to the light of a Sinus-270 solar simulator (Class AAA, Wavelabs), which provided a solar spectrum with an irradiance equivalent to 100 mm × 100 mm. The simulator was placed 36 cm from the solar cell and used a 100 mm × 100 mm illumination spot. The simulator was connected to a Keithley™ 2401 digital multimeter, which was connected to a personal computer for data collection. Current-voltage density curves (JV) were obtained by measuring the current value at a given voltage range between 100 mV and 1,200 mV. The measurement rate was 100 mV / s. The current value was measured by changing the direction of the curve acquisition [reverse scan, i.e., V oc (open circuit voltage) to J sc (short-circuit photocurrent density), and forward scan, i.e., J sc (short-circuit photocurrent density) to V oc (open circuit voltage)], while other acquisition parameters were fixed. Table 1 shows the characteristic parameters as average values.

[0085] The light intensity was calibrated using a standard silicon solar cell (Centronic OSD50-0-KG5).

[0086] [Table 1]

[0087] Example 11 (Invention) Fabrication of perovskite solar cells using the ink obtained in Example 2 Perovskite solar cells were obtained using the same procedure as described in Example 10, the only difference being that the ink obtained in Example 2 was used.

[0088] For this purpose, 90 μl of the ink obtained in Example 2 was deposited on a mesoporous titanium dioxide (TiO2) layer by spin coating carried out at a rotation speed of 3,000 rpm (acceleration of 1,000 rpm / s) for 30 seconds, and the whole was subjected to a heat treatment (annealing) at 180 °C for 10 minutes. The thickness of the perovskite layer was found to be 450 nm.

[0089] The electrical characterization of the obtained perovskite solar cells was carried out as described above, and the characteristic parameters are reported as average values ​​in Table 2.

[0090] [Table 2]

[0091] Example 12 (Invention) Fabrication of perovskite solar cells using the ink obtained in Example 3 Perovskite solar cells were obtained using the same procedure as described in Example 10, the only difference being that the ink obtained in Example 3 was used.

[0092] For this purpose, 90 μl of the ink obtained in Example 3 was deposited on a mesoporous titanium dioxide (TiO2) layer by spin coating carried out at a rotation speed of 3,000 rpm (acceleration of 1,000 rpm / s) for 30 seconds, and the whole was subjected to a heat treatment (annealing) at 180 °C for 10 minutes. The thickness of the perovskite layer was found to be 450 nm.

[0093] The electrical characterization of the obtained perovskite solar cells was carried out as described above, and the characteristic parameters are reported as average values ​​in Table 3.

[0094] [Table 3]

[0095] Example 13 Fabrication of perovskite solar cells using the ink obtained in Example 4 Perovskite solar cells were obtained using the same procedure as described in Example 10, the only difference being that the ink obtained in Example 4 was used.

[0096] For this purpose, 90 μl of the ink obtained in Example 2 was deposited on a mesoporous titanium dioxide (TiO2) layer by spin coating carried out at a rotation speed of 3,000 rpm (acceleration of 1,000 rpm / s) for 30 seconds, and the whole was subjected to a heat treatment (annealing) at 180 °C for 10 minutes. The thickness of the perovskite layer was found to be 450 nm.

[0097] The electrical characterization of the obtained perovskite solar cells was carried out as described above, and the characteristic parameters are reported as average values ​​in Table 4.

[0098] [Table 4]

Claims

1. A method for producing a perovskite-based ink, comprising: forming a perovskite having the following general formula (I): CsPbI ３－ｙ Br ｙ (I) (wherein y is a number in the range of 0 to 0.2, preferably in the range of 0.05 to 0.1), (a) Lead iodide (PbI ２ ) in at least one organic solvent selected from dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), γ-butyrolactone (GBL), or a mixture thereof, preferably dimethyl sulfoxide (DMSO), dimethyl formamide (DMF), or a mixture thereof, to obtain a first solution; (b) adding cesium iodide (CsI) and a compound represented by the following general formula (II): R ｘ 8 ４－ｘ 99 (99) (wherein R is a linear or branched C １ ~C ４ represents an alkyl group, preferably a methyl group, and x is an integer ranging from 2 to 4, preferably 2. and at least one ammonium salt represented by the formula (I) to obtain a second solution; (c) adding cesium iodide (CsI) and a compound represented by the following general formula (III): R ｘ H ４－ｘ NBr (III) (wherein R is a linear or branched C １ ~C ４ represents an alkyl group, preferably a methyl group, and x is an integer ranging from 2 to 4, preferably 2. and at least one ammonium salt represented by the formula (I) to obtain a third solution; (d) mixing the second solution obtained in step (b) with the third solution obtained in step (c) to obtain a perovskite-based ink; Including, In the step (d), the molar ratio of the at least one ammonium salt represented by general formula (II) to the at least one ammonium salt represented by general formula (III) is within the range of 0:100 to 50:

50.

2. 2. A method for producing a perovskite-based ink according to claim 1, wherein the at least one ammonium salt represented by general formula (II) is dimethylammonium iodide (DMAI).

3. 3. A method for producing a perovskite-based ink according to claim 1 or 2, wherein the at least one ammonium salt represented by general formula (III) is dimethylammonium bromide (DMABr).

4. The step (a) at a temperature in the range of 30°C to 80°C, preferably in the range of 40°C to 70°C, and / or for a time in the range of 1 hour to 12 hours, preferably in the range of 4 hours to 11 hours, A method for producing a perovskite-based ink according to any one of claims 1 to 3, comprising:

5. The step (b) at a temperature in the range of 15°C to 35°C, preferably in the range of 20°C to 30°C, more preferably at room temperature (25°C); and / or for a time in the range of 5 minutes to 2 hours, preferably in the range of 10 minutes to 1 hour, A method for producing a perovskite-based ink according to any one of claims 1 to 4, comprising:

6. The step (c), at a temperature in the range of 15°C to 35°C, preferably in the range of 20°C to 30°C, more preferably at room temperature (25°C); and / or for a time in the range of 5 minutes to 2 hours, preferably in the range of 10 minutes to 1 hour, 6. A method for producing a perovskite-based ink according to any one of claims 1 to 5, wherein

7. The step (d) at a temperature in the range of 15°C to 35°C, preferably in the range of 20°C to 30°C, more preferably at room temperature (25°C); and / or for a time in the range of 5 minutes to 2 hours, preferably in the range of 8 minutes to 1 hour, A method for producing a perovskite-based ink according to any one of claims 1 to 6, comprising:

8. 8. A method for producing a perovskite film, the method comprising the steps of: (i) depositing a perovskite-based ink obtained by the method of any one of claims 1 to 7 onto a substrate to form a film; and (ii) subjecting the substrate to a heat treatment (annealing) at a temperature in the range of 120°C to 190°C, preferably in the range of 135°C to 185°C.

9. 1. A method for manufacturing a perovskite photovoltaic cell (or solar cell), comprising: (a １ ) providing a glass substrate coated with a transparent conductive oxide layer (Transparent Conductive Oxide - TCO) (anode); (b １ ) depositing a layer based on an electron transport material (electron transport layer - ETL); (c １ ) optionally, the step (b １ depositing a mesoporous oxide-based layer (scaffold) on the layer based on the electron transport material obtained in step (electron transport layer - ETL); (d １ ) the step (b) １ a layer based on an electron transport material obtained in step (c) (electron transport layer - ETL), or １ depositing a perovskite-based ink obtained by the method of any one of claims 1 to 7 onto the mesoporous oxide-based layer (scaffold) obtained in step (a), to obtain a photoactive layer; (e １ ) the step (d １ depositing a layer based on a hole transport material (hole transport layer - HTL) on the photoactive layer obtained in step (a); (f １ ) the step (e １ depositing a metal contact (back contact) constituting the cathode on the layer based on a hole transport material (hole transport layer - HTL) obtained in step (a); and the step (d １ ) is carried out at a temperature in the range of 120°C to 190°C, preferably in the range of 135°C to 185°C.

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