Method for producing perovskite structures

Abstract

The present invention relates to a method for producing perovskite structures on a substrate surface, wherein the perovskite has the general structure ABX3, where A is at least partially an organic compound, and the method uses a source of the organic compound that is halide-free. Improved photovoltaic properties of the resulting perovskite are obtained, and the method allows for large-scale production.

Description

[Technical Field]

[0001] The present invention relates to a method and apparatus for producing perovskite structures having the general structure ABX3 on a substrate, where A is at least partially an organic compound, and the method and apparatus uses two different sources of the organic compound. The method and apparatus can be used to produce solar cells. [Background technology]

[0002] Perovskite semiconductor thin films are most commonly produced using solution-based methods. While high efficiencies have been achieved in solar cells made with such perovskite materials, solution-based methods present certain challenges that make them less suitable for industrial applications. One is the difficulty in upscaling to the large-area, high-throughput processes required for mass production. Another challenge is related to the use of solvents. The solvent must be removed, and any residue left behind can potentially cause electrically active defects, either from impurities or the formation of internal surfaces related to porosity. One thin-film deposition method already demonstrated for mass production of semiconductor thin films is vacuum evaporation. Vacuum evaporation is strictly additive in nature and can yield films of very high purity. On the other hand, vacuum evaporation of multicomponent thin films requires very precise control of the vapor fluxes of the different components.

[0003] The perovskite materials most widely used in solar cells have a composition that can be described as ABX3. A, B, and X occupy specific lattice positions in the perovskite crystal structure. A is typically an organic molecule, such as methylammonium (MA) or formamidinium (FA), or a mixture of the two, or a mixture of an organic molecule and Cs. While other elements are possible, Cs is the most widely used element. In all perovskites that have yielded high-efficiency (>20%) solar cells to date, B is Pb. X can be I, a mixture of I and Br, or Cl. Thus, many high-performance perovskites have the general formula (MA,FA,Cs)Pb(I,Br)3.

[0004] If such a film is made by vapor deposition, a typical set of evaporation sources would be one with formamidinium iodide (FAI), one with PbI2 (lead iodide), and one with CsBr (cesium bromide). Optionally, there could also be a source with methylammonium iodide (MAI). However, more efficient and more controlled methods are still needed to enable the scaling up of fabrication processes to large scale production. Summary of the Invention [Problem to be solved by the invention]

[0005] It is an object of the present invention to overcome the shortcomings of the prior art by providing a method and apparatus for producing perovskite films that facilitates both control of structure formation and large-scale production. [Means for solving the problem]

[0006] In a first aspect, the present invention relates to a method according to claim 1.

[0007] In a second aspect, the invention relates to an apparatus (10) for producing a perovskite structure on a substrate surface (11), wherein the perovskite has the general structure ABX3, component A is an organic molecule or a mixture of organic molecules, or A is cesium, potassium and / or rubidium, or a mixture of organic molecules and cesium, potassium and / or rubidium, component B is lead and / or tin, and component X is a halide; The apparatus comprises a vacuum chamber (12) having a substrate inlet (14) and a substrate outlet (16); the vacuum chamber comprises at least one deposition zone (18), in which at least a first evaporation source (20) and a second evaporation source (22) of a component are disposed, the first evaporation source (20) containing a component AX, and the second evaporation source (22) containing a component BX; a third supply source is provided, the third supply source being either a third evaporation source (24) containing component A as a salt provided in the deposition zone (18) or in an evaporation reactor (26) in vapor connection with the deposition zone of the vacuum chamber, or an external supply source (28) containing a gas containing component A provided in vapor connection with the deposition zone, the salt comprising an organic molecule or a mixture of organic molecules as a cation and whose anion is not a halide, the gas contained in the external supply source (28) comprising formamidine, formamidinium, methylammonium or methylamine; The vacuum chamber (12) and optional evaporation reactor (26) are equipped with heating devices (29) configured to separately heat evaporation sources at reduced pressure to evaporate components and produce a stream of the components, and the vacuum chamber is configured to contact the stream with the substrate surface. This relates to the device (10). [Brief explanation of the drawings]

[0008] [Figure 1] Process pressure for different deposition times with and without the supply of FAAc (formamidine acetate) during the co-evaporation process (triangular or circular data points, respectively). [Figure 2]PCE of perovskite solar cell device (A = 0.126 cm2) determined by IV measurements performed under standard test conditions using a class AAA solar simulator. [Figure 3] 1 is a schematic diagram of an apparatus according to the invention, the dotted lines indicating communication. DETAILED DESCRIPTION OF THE INVENTION

[0009] Below is a non-limiting list of embodiments:

[0010] In one embodiment of any of the aspects of the invention, the first evaporation source component AX and the second evaporation source component BX are each in the form of a solid, preferably a powder, upon heating.

[0011] In one embodiment of any of the aspects of the invention, component AX of the first evaporation source is selected from formamidinium iodide, formamidinium bromide, formamidinium chloride, methylammonium iodide, methylammonium bromide, or methylammonium chloride, or a combination of two or more thereof.

[0012] In one embodiment of any of the aspects of the invention, the component BX of the second evaporation source is selected from lead iodide (PbI), lead bromide (PbBr) or lead chloride (PbCl), or a combination of two or more thereof, or from tin iodide (SnI or SnI), tin bromide (SnBr or SnBr), or tin chloride (SnCl or SnCl), or a combination of two or more thereof.

[0013] In one embodiment of any of the aspects of the invention, a third evaporation source is provided and comprises component A as a salt, wherein the anion is selected from acetate, formate, tetrafluoroborate, hexafluorophosphate and thiocyanate, and the salt is preferably selected from formamidinium acetate or methylammonium acetate or a combination thereof, and the salt is preferably in the form of a powder.

[0014] In one embodiment of any of the aspects of the invention, an external source is provided containing a gas comprising component A, the gas being purified before entering the deposition zone.

[0015] In one embodiment of any of the aspects of the invention, the invention comprises providing a fourth evaporation source comprising a component AX, wherein A is cesium, potassium and / or rubidium, and AX is preferably selected from cesium acetate, cesium formate, cesium iodide (CsI) and cesium bromide (CsBr); heating the fourth evaporation source to produce a stream of components to evaporate the components of the fourth evaporation source at reduced pressure; and contacting the stream of evaporated components with a substrate surface in a deposition zone to allow the components to form a perovskite structure on the surface.

[0016] In one embodiment, component A is selected from formamidine, formamidinium, methylammonium and / or methylamine.

[0017] In one embodiment of any of the aspects of the invention, the reduced pressure in the deposition zone is 1×10 -4 lower than mbar.

[0018] In one embodiment of any of the aspects of the invention, the substrate has a multilayer structure including a preferred layer, for example a transparent conductive oxide (TCO) layer and a hole transport layer or an electron transport layer.

[0019] In one embodiment of any of the aspects of the invention, the third evaporation source is disposed within an evaporation reactor in vapor communication with the deposition zone, and the method preferably includes purifying the stream of evaporated components from the third evaporation source before it enters the deposition zone.

[0020] In one embodiment of any of the aspects of the invention, the flow of the components is monitored using at least one suitable detector located in the deposition zone, preferably by using one or more quartz crystal based flow detectors or mass spectrometry.

[0021] In one embodiment of any of the aspects of the present invention, components of at least the first evaporation source, the second evaporation source and preferably also the third evaporation source are co-evaporated.

[0022] In one embodiment of any of the aspects of the invention, the substrate has a temperature that is lower than the temperature of the components in the flow.

[0023] In one embodiment of any of the aspects of the invention, the vacuum chamber or vacuum apparatus is configured to allow one or more substrates to be automatically moved into and out of the vacuum chamber via the substrate inlet (14) and substrate outlet (16), respectively, which may be accomplished by the substrates being placed and transported on a continuously moving belt through the chamber.

[0024] Preferably, the access port of the vacuum chamber is arranged to seal the chamber to maintain the vacuum therein, which may be achieved by using suitable vacuum locks and / or valves.

[0025] In one embodiment of the second aspect of the present invention, the apparatus is configured for in-line continuous production of perovskite structures on substrate surfaces by allowing substrates to enter a vacuum chamber via a substrate inlet, be transported from the substrate inlet through a deposition zone to a substrate outlet, and then exit the vacuum chamber. This can be achieved by a vacuum lock. When the lock is open, the substrate is moved into the lock, then the valve to the atmosphere is closed, the lock is evacuated, then the valve to the process vacuum chamber is opened, and the substrate is transported into the process chamber. When the process chamber is closed, the substrate is accelerated to a certain movement speed where the actual deposition process is performed. The acceleration is controlled to allow substrates to catch up with preceding substrates to form a train of substrates that progress through the actual deposition zone of the in-line process equipment without interrupting the deposition process to achieve high productivity. After deposition, the substrates are locked out of the process vacuum chamber one by one by a reverse lock-in sequence.

[0026] In one embodiment of the second aspect of the present invention, the third evaporation source (24) is disposed within the evaporation reactor (26), and the apparatus preferably comprises a purification device (30) configured to purify the vaporized components from the third evaporation source before they enter the deposition zone.

[0027] In one embodiment of any of the aspects of the invention, an external source (28) containing a gas comprising component A is provided in vapor connection with the deposition zone, and the apparatus preferably comprises purification equipment (31) configured to purify the gas before it enters the deposition zone.

[0028] In one embodiment of the second aspect of the present invention, the apparatus further comprises at least one detector (32) and a control unit (34) operably connected to the at least one detector (32). The at least one detector (32) is configured to detect or measure at least one characteristic of the apparatus and send a signal indicative of the at least one characteristic to the control unit (34). The control unit (34) is configured to control at least one of a heating device (29), a pressure device (36), or a flow control device for the evaporation reactor (26) or the external source (28).

[0029] In one embodiment of the second aspect of the present invention, the device comprises a detector (32), which is a quartz crystal type flow detector.

[0030] All embodiments may be combined unless otherwise stated.

[0031] Detailed Description

[0032] method The method according to the present invention aims to produce a perovskite structure or a film of a perovskite structure on a substrate surface, the perovskite having the general structure ABX3. Component A is selected from an organic molecule or a mixture of organic molecules, cesium, potassium and / or rubidium, and a mixture of an organic molecule with cesium, potassium and / or rubidium. In one embodiment, A is a mixture of an organic molecule and cesium. When component A is an organic molecule, it is preferably formamidine, formamidinium, methylammonium and / or methylamine. Component B is lead and / or tin, and X is a halide, preferably iodide and / or bromide. In one embodiment, the perovskite structure is a compound of A 1-x Cs x Pb y I 2-x+y Br x where x is 0.30±0.05, y is 1.1±0.1, and A is formamidinium or methylammonium. The thickness of the perovskite film on the substrate is preferably within the range of 0.1 to 2.0 μm, more preferably 0.2 to 1.0 μm.

[0033] Perovskite structures or perovskite films are produced by depositing components in the vapor phase onto the surface of a substrate placed in a deposition zone within a vacuum chamber. At least one first evaporation source and at least one second evaporation source are provided, containing component AX and component BX, respectively. The first evaporation source and second evaporation source are preferably located within the deposition zone. In one embodiment, at least two first evaporation sources are provided, a primary first evaporation source and a secondary first evaporation source. In another embodiment, at least two second evaporation sources are provided, a primary second evaporation source and a secondary second evaporation source. The substrate can be placed horizontally above the evaporation sources or vertically adjacent to the evaporation sources. The components of the first and second evaporation sources are preferably in solid, preferably powder, form, which is advantageous because it avoids the use of solvents. A third source is also provided, which is an additional source of component A as an organic molecule or a mixture of organic molecules. In one embodiment, the third source is a third evaporation source containing component A as a salt, where the salt contains an organic molecule or mixture of organic molecules as the cation, and the anion is not a halide. By using a salt of A whose anion is not a halide, such as iodide or bromide, it is possible to provide the organic component without providing additional halides that may interfere with or prevent the formation of the desired perovskite structure and composition. A non-limiting list of preferred anions is acetate, formate, tetrafluoroborate, hexafluorophosphate, and thiocyanate. The third evaporation source is preferably located within the deposition zone or within an evaporation reactor in vapor communication with the deposition zone. In another embodiment, the third source is an external source, from which component A is provided as a gas to the deposition zone. The gas includes component A, where component A is formamidine, formamidinium, methylammonium, and / or methylamine. The advantage of using an external gas source for component A is that it is possible to provide the organic compound without further providing additional halides, and furthermore the gas can be purified before entering the deposition zone, which may result in better control of the structure as well as better photovoltaic properties of the perovskite layer.A fourth evaporation source may also be provided in the deposition zone or evaporation reactor. The fourth evaporation source contains component A as a cation, where A is cesium, potassium, and / or rubidium, and the anion is preferably selected from acetate, formate, iodide, and bromide. In one preferred embodiment, the fourth evaporation source contains cesium acetate, cesium formate, cesium iodide (CsI), and / or cesium bromide (CsBr). Evaporation of the components of the fourth evaporation source is carried out at reduced pressure, as described above, preferably by heating.

[0034] The streams of components A, B, and X are produced by evaporating the components from the evaporation sources by heating at least the first, second, and optionally the third evaporation source at reduced pressure, and / or by providing a gaseous stream of component A from an external source. The evaporation sources are heated separately to better control the composition of the evaporated component streams. In one embodiment, the first, second, and third evaporation sources are heated separately to temperatures between 20 and 300°C, preferably between 50 and 200°C. In one embodiment, the third evaporation source is heated to a temperature between 20 and 150°C, preferably between 50 and 100°C. In one embodiment, the third evaporation source is placed within an evaporation reactor and is not heated during evaporation. The reduced pressure during evaporation is preferably less than 5×10 -4 mbar, preferably below 1×10 -4 lower than mbar, but preferably 1 x 10 -5 mbar or more.

[0035] The component flow is then contacted with the substrate surface in the deposition zone, allowing the components to form a perovskite structure on the surface. The components of the first and second evaporation sources are preferably co-evaporated, and preferably also the components of the third evaporation source. The component flow is adjusted to obtain the desired structure and composition on the substrate surface by adapting the evaporation source heating temperature and the flow from the external source or evaporation reactor. Preferably, the flow rate or deposition rate is monitored using at least one suitable detector located in the deposition zone, preferably one or more quartz crystal flow detectors or mass spectrometry. The control unit communicates with the detector, the evaporation source heating device, and preferably also with a pressure device that adjusts the pressure in the vacuum chamber. In one embodiment, the flow rate or deposition rate is monitored prior to deposition on the substrate surface, and when a stable, desired, or predetermined flow rate or deposition rate is reached, the component flow is contacted with the substrate surface to be deposited. The resulting substrate with a perovskite structure can then be further processed depending on the use of the substrate. In a preferred embodiment, the obtained perovskite structure is annealed at a temperature preferably between 30 and 150°C, more preferably between 40 and 120°C.

[0036] In a preferred embodiment, the component AX of at least one first evaporation source is selected from formamidinium iodide, formamidinium bromide, formamidinium chloride, methylammonium iodide, methylammonium bromide, or methylammonium chloride, or a combination of two or more thereof. In another preferred embodiment, the component BX of at least one second evaporation source is selected from lead iodide (PbI), lead bromide (PbBr), or lead chloride (PbCl), or a combination of two or more thereof, or tin iodide (SnI or SnI), tin bromide (SnBr or SnBr), or tin chloride (SnCl or SnCl), or a combination of two or more thereof. In yet another preferred embodiment, a third evaporation source is provided. The third evaporation source includes component A as a salt, where component A is a cation and the anion is selected from acetate, formate, tetrafluoroborate, hexafluorophosphate, and thiocyanate. Preferably, the salt is selected from formamidinium acetate or methylammonium acetate, or a combination thereof, and the salt is preferably in powder form. In one embodiment, the third evaporation source is provided in an evaporation reactor in vapor connection with the deposition zone, and the method preferably includes a step of purifying the evaporated component stream from the third evaporation source before it enters the deposition zone. The advantage of having the third evaporation source in an external evaporation reactor is that the flow rates or deposition rates of components A, B, and X can be more easily adjusted separately by adjusting evaporation parameters, such as temperature and pressure. In one embodiment, the gas from the external source or from the evaporation reactor is provided at an excess pressure relative to the desired perovskite structure, facilitating better control.

[0037] In one embodiment, component X of the perovskite structure is a mixture of at least two halides, preferably iodide and bromide, component AX of the first evaporation source is preferably formamidinium bromide or methylammonium bromide, and component BX of the second evaporation source is preferably PbI2. In another embodiment, component A of the perovskite structure is a mixture of an organic molecule and one of cesium, potassium, or rubidium, preferably cesium. A fourth evaporation source is preferably provided. The fourth evaporation source includes component A, which is an organic molecule, or a mixture of organic molecules, or a mixture of organic molecules and cesium, potassium, and / or rubidium, but is different from component A of the first evaporation source. In one embodiment, component A of the fourth evaporation source is preferably cesium, such as CsBr, cesium acetate, or cesium formate, and the first evaporation source preferably comprises an organic molecule, such as formamidinium iodide, formamidinium bromide, formamidinium chloride, methylammonium iodide, methylammonium bromide, or methylammonium chloride. The fourth evaporation source can be located within the deposition zone or within an evaporation reactor in vapor communication with the deposition zone. The fourth evaporation source can be part of or mixed with the first or second evaporation source.

[0038] The substrate can be any suitable substrate, such as a silicon wafer, preferably a metal or polymer foil, or glass. The substrate is preferably coated with a multilayer structure including a layer, such as a transparent conductive oxide (TCO) layer and a hole transport layer or an electron transport layer. During the method, the substrate can be heated or cooled using any suitable means to allow the components to condense and / or react on the surface and form a perovskite. In one embodiment, the substrate has a temperature lower than the temperature of the evaporated components to promote condensation of the components. In one embodiment, the temperature of the substrate is 20-40°C. In one embodiment, the method is part of a process for manufacturing a photovoltaic part or component.

[0039] To illustrate this method and its advantages, the production of a non-limiting perovskite with the structure FAPbI3 is disclosed. This structure can be produced by vacuum deposition of FAI (formamidinium iodide) and PbI2 according to prior art methods. If the two components evaporate at exactly the same molecular rate, the resulting film would ideally have the desired composition. However, controlling FAI evaporation is difficult because the FA dissociates, by-products interfere with the process, and diffusion of the evaporating molecules and atoms increases the process pressure, limiting the deposition rate. The dissociated components may adhere or deposit differently, and not all components of the FAI may be incorporated into the film in the same ratio, resulting in non-stoichiometric perovskite material. Furthermore, CVD-like reactions can lead to the growth of more complex perovskite films. Another complication is that iodine from FAI evaporates in the form of hydrogen iodide, which is corrosive and toxic. All of these vapor components can have different adhesion or deposition properties on the growing film, making it very difficult to control the composition of the perovskite material, in part due to the interdependence between the amount of FA and I from the FAI source. The present invention solves these problems by using an additional source of organic molecules that do not contain any other perovskite structure components. In this specific, non-limiting example, formamidinium acetate can be used as the formamidinium evaporation source (third evaporation source).

[0040] The evaporation of formamidinium acetate allows for the addition of formamidinium molecules to the process without the simultaneous addition of iodine, so by balancing the amount of iodine with the amount of formamidinium added to the growing film, it is possible to obtain the desired perovskite composition in this manner.

[0041] Evaporation of formamidinium acetate has additional advantages over providing all formamidinium from a FAI source. For one, the vapor pressure of formamidine is relatively higher than that of formamidinium acetate, allowing it to evaporate at lower temperatures compared to formamidine from a FAI source. The lower temperature reduces the degree of dissociation of formamidinium molecules, allowing the background pressure of undesired molecules to be kept low. The high vapor pressure also promotes a relatively small evaporation surface for a given formamidine flux. A convenient configuration that takes advantage of this property is an external evaporation reactor or an external source, where formamidine vapor is transported to the deposition zone in a tube. An additional advantage of an external source or evaporation reactor is that the vapor can be purified before being discharged into the deposition zone, thereby reducing the impurity level and undesired molecular or atomic content within the zone and the resulting structure.

[0042] The method allows for in-line production of perovskite structures on a substrate surface, which may facilitate large-scale production. In one embodiment, the substrate enters the vacuum chamber via a substrate inlet, is transported from said inlet through a deposition zone for deposition of the perovskite according to the invention, to a substrate outlet, and then exits the vacuum chamber, the transport being automated.

[0043] As shown in the examples and illustrated in Figures 1 and 2, the present invention facilitates faster deposition rates and thereby high speed production without compromising the quality of the resulting perovskite layer.

[0044] Device According to the present invention, the apparatus (10) is suitable for producing a perovskite structure or a perovskite-structured film, as described above, on a substrate surface (11) disposed within a vacuum chamber (12) of the apparatus. A substrate inlet (14) and a substrate outlet (16) are disposed within the vacuum chamber (12), respectively, so that the substrate can enter and exit the vacuum chamber. The substrate inlet and outlet preferably comprise suitable closure devices, such as vacuum load locks. The vacuum chamber (12) includes at least one deposition zone (18). The deposition zone (18) also includes at least one first evaporation source (20), at least one second evaporation source (22), and an optional third evaporation source (24). The first evaporation source (20) contains a component AX, the second evaporation source (22) contains a component BX, and the third evaporation source contains a perovskite-structured component A. The third vaporization source (24) may be located in a vaporization reactor (26) in vapor connection with the deposition zone (18), or component A is a gas provided in an external source (28) in vapor connection with the deposition zone.

[0045] The vacuum chamber (12) is configured to allow a substrate to enter via a substrate inlet (14) and be positioned within a deposition zone (18) so that flows of components from the evaporation source, evaporation reactor, and external sources contact the substrate surface. The vacuum chamber (12) is configured to allow a substrate to exit via a substrate outlet (16). A pressure device (36) is disposed within the apparatus configured to create and regulate pressure within the vacuum chamber (12) and the evaporation reactor (26), and the pressure device is preferably any suitable pump, such as a vacuum pump.

[0046] An advantage of the present invention is that it enables continuous in-line production of perovskites. This is possible by allowing substrates to enter a vacuum chamber via a substrate inlet, be transported from the inlet through a deposition zone for perovskite deposition to a substrate outlet, and then automatically exit the vacuum chamber. Preferably, the substrate inlet and outlet have appropriate closure devices, preferably vacuum load locks. In a preferred embodiment, at least one first evaporation source, at least one second evaporation source, a third evaporation source, or an evaporation reactor comprising a third evaporation source, or an external source, is arranged along the substrate movement path. The use of an evaporation reactor comprising a third evaporation source or an external source containing component A as a gas is advantageous in in-line production because it requires less space in the deposition zone than a solid evaporation source and allows more flexibility in terms of flow composition and flow optimization.

[0047] To evaporate components from the first, second, and third evaporation sources, the vacuum chamber (12) and optional evaporation reactor (26) are equipped with heating devices (29) configured to separately heat the sources, and pressure devices (36) are configured to reduce the pressure in the vacuum chamber (12) and optional evaporation reactor (26). Using the evaporation reactor (26) to evaporate the third evaporation source (24) or an external source (28) for component A in the vapor phase has the advantage that the component stream can be purified before entering the vacuum chamber and the deposition zone. If the third evaporation source (24) is located within the evaporation reactor (26), the apparatus preferably includes a purification device (30) configured to purify the component vaporized from the third evaporation source before entering the deposition zone. If the external source (28) containing component A as a gas is provided in vapor connection with the deposition zone (18), the apparatus preferably includes a purification device (31) configured to purify the gas before entering the deposition zone. The purification device (30) or (31) is preferably any suitable filter. Non-limiting examples of purification devices are membrane gas separation devices and selective gas traps.

[0048] Depending on the composition of the evaporation source, the amount of heat required to evaporate the components at reduced pressure may vary. The evaporation sources are preferably heated separately, i.e., each evaporation source is heated separately, and the heating device (29) may be any suitable heating device, for example, an electric heater. The pressure device (36) is suitably positioned to create and maintain reduced pressure within the vacuum chamber and optional evaporation reactor (26).

[0049] The apparatus (10) further comprises at least one detector (32) suitably disposed inside the vacuum chamber (12) and configured to measure or detect at least one property of the apparatus. The property is preferably temperature, pressure, the composition of evaporated components inside the vacuum chamber (12), or a property of the perovskite structure formed on the substrate. In some embodiments, multiple detectors (32) may be disposed inside the vacuum chamber (12) and configured to measure or detect the same property or different parameters. The apparatus (10) also suitably comprises a control unit (34) operably connected to the at least one detector (32), such that signals can be transmitted from the at least one detector (32) to the control unit (34) and, optionally, from the control unit (34) to the at least one detector (32).

[0050] Additionally, the control unit (34) includes processing circuitry suitably configured to control at least one characteristic of the apparatus (10). In some embodiments, this is accomplished by the control unit (34) being configured to control the heating device (29). In other embodiments, the control unit (34) may also, or instead, be configured to control the supply of a third source from the evaporation reactor (26) or the external source (28) by operating a flow control device (not shown), such as a control valve or the like, thereby controlling the flow of the third source or the external source. The control unit (34) may also, or alternatively, be configured to control the pressure within the vacuum chamber (12), for example, by operating a pressure device (36).

[0051] As a result, the control unit (34) is operable to monitor at least one property within the vacuum chamber (12) and may also be operable to control at least one property by operating any or all of the heating equipment, the vacuum pump and the supply of the third source, which has the advantage that the conditions inside the vacuum chamber (12) can be controlled and therefore the desired quality of the perovskite produced can be achieved.

[0052] Non-limiting examples of suitable detectors include quartz crystal flow detectors and mass detectors, such as mass spectrometers. The quartz crystal flow detectors are preferably arranged so that each detector detects only the flow from one evaporation source. When an external source or evaporation reactor is used, a mass spectrometer is preferably used. By monitoring the composition of the flow over time, the structure of the perovskite can be controlled, especially in in-line production, where the evaporation source, evaporation reactor, and external source are arranged along the substrate movement path.

[0053] The vacuum chamber (12) is preferably further configured to anneal the resulting perovskite structure on the substrate surface, in one embodiment the vacuum chamber is configured to heat the resulting perovskite structure to a temperature of between 30 and 150°C. [Example]

[0054] Example 1 Elemental Composition FA 1-x Cs x Pb y I 2-x+y Br xThin-film perovskite solar cell absorber layers with (x=0.30±0.05, y=1.1±0.1) were deposited on NiO-coated glass substrates by thermal co-evaporation of PbI, CsBr, and formamidinium iodide (FAI), all in powder form, to yield a film thickness of 0.6±0.1 μm. An additional supply of formamidinium acetate (FAAc) was optionally added as an additional source of formamidinium to compensate for loss of formamidinium due to decomposition. All film depositions were performed as follows: Estimated evaporation temperatures were approximately 300°C for PbI, approximately 450°C for CsBr, approximately 150°C for FAI, and approximately 80°C for FAAc.

[0055] The process is <2 x 10 -6 Depositions using FAAc were started at a base pressure of 1 × 10 mbar. -5 FAAc at mbar was supplied via an external source consisting of a stainless steel bottle heated to 80±5° C. The gas inlet port was pointed away from the substrate.

[0056] Evaporation of PbI2, CsBr, and FAI was initiated by gradually increasing the power of the heater surrounding the source crucible, which was placed below the substrate and in the line of sight. The evaporation rate remained stable for 25 minutes while the substrate shutter remained closed. The individual evaporation rates of the constituents, and therefore the film composition, were also controlled by quadrupole mass spectrometry feedback. After the evaporation rate stabilized, the substrate shutter was opened and film deposition began. The deposition rate was adjusted to achieve a film thickness of 0.6 ± 0.1 μm for deposition times of 12, 20, 30, 40, or 60 minutes. The substrate shutter was then closed and the source heater was turned off. After perovskite deposition, the composition was determined by X-ray fluorescence and / or C60 / In2O. x The ZnO was further processed into a solar cell device by deposition of a Zn transparent electron-selective contact.

[0057] The process pressure is higher for processes with faster deposition rates due to the evaporation species, both desired and undesired dissociation products, creating a background pressure in the vacuum chamber. This is illustrated in Figure 1, which shows the process pressure measured at different deposition times. Each data point corresponds to one deposition. More importantly, Figure 1 also shows the effect of adding FAAc. The process pressure measured without FAAc supply was approximately 2-4 × 10 for a 60-minute process. -5 mbar. 1×10 -5 By supplying 100 mbar of FAAc, it was possible to significantly increase the deposition rate while maintaining (or decreasing) the process pressure.

[0058] Reducing the deposition time from 30 minutes to 12 minutes by increasing the deposition rate does not necessarily result in a decrease in the power conversion efficiency (PCE) of the solar cell device. This is shown in Figure 2 and Table 1, which contain PCE values measured under standard test conditions for solar cell devices fabricated using a perovskite absorber layer deposited by the described process and a sputtered transparent conductive oxide as the top electrode, with a vapor-deposited C60 buffer layer in between.

[0059] [Table 1]

Claims

1. A method for producing a perovskite structure on a substrate surface, the perovskite being selected from the group consisting of ABX ３ wherein component A is an organic molecule or a mixture of organic molecules, or A is cesium, potassium and / or rubidium, or a mixture of an organic molecule and cesium, potassium and / or rubidium, component B is lead and / or tin, and component X is a halide, and the process comprises a. providing a substrate in a deposition zone within a vacuum chamber; b) providing at least first and second evaporation sources of components, wherein the first evaporation source comprises components A-X and the second evaporation source comprises components B-X; providing a third source, wherein the third source is a third evaporation source comprising component A as a salt or the third source is an external source containing a gas comprising component A, wherein the salt comprises an organic molecule or a mixture of organic molecules as a cation and the anion is not a halide; and the gas contained in the external source comprises formamidine, formamidinium, methylammonium, or methylamine; c. providing a stream of components A, B, and X in the vapor phase by evaporating the components by heating the first and second evaporation sources at reduced pressure, and by evaporating component A from the third evaporation source at reduced pressure, or by providing a stream of gas from the external source; d. contacting the streams of components A, B and X with a substrate surface in a deposition zone and allowing said components to form a perovskite structure on said substrate surface; A method comprising:

2. 2. The method of claim 1, wherein the components AX and BX of the first and second evaporation sources, respectively, are in the form of a solid, preferably a powder, upon heating.

3. 3. The method of claim 1 or claim 2, wherein components A-X of the first evaporation source are selected from formamidinium iodide, formamidinium bromide, formamidinium chloride, methylammonium iodide, methylammonium bromide, or methylammonium chloride, or a combination of two or more thereof.

4. The component B-X of the second evaporation source is lead iodide (PbI ２ ), lead bromide (PbBr ２ ) or lead chloride (PbCl ２ ), or a combination of two or more thereof, or tin iodide (SnI ２ or SnI ４ ), tin bromide (SnBr ２ or SnBr ４ ) or tin chloride (SnCl ２ or SnCl ４ 4. The method of claim 1 , wherein the hydroxyl group is selected from the group consisting of hydroxyl group, hydroxypropyl group, hydroxypropyl group, hydroxypropyl methyl ...

5. 5. The method according to any one of claims 1 to 4, wherein the third evaporation source is provided and comprises component A as a salt, the anion being selected from acetate, formate, tetrafluoroborate, hexafluorophosphate and thiocyanate, the salt being preferably selected from formamidinium acetate or methylammonium acetate, or a combination thereof, and the salt being preferably in the form of a powder.

6. 5. The method of claim 1, wherein the external source is provided containing a gas comprising component A, the gas being purified before entering the deposition zone.

7. providing a fourth evaporation source, said fourth evaporation source comprising component A as a cation, A being cesium, potassium and / or rubidium, and an anion preferably selected from acetate, formate, iodide and bromide, preferably said fourth evaporation source being selected from cesium acetate, cesium formate, cesium iodide (CsI) and cesium bromide (CsBr); evaporating a component of the fourth evaporation source at reduced pressure by heating the fourth evaporation source to produce a flow of the component, and contacting the flow of evaporated component with a substrate surface in a deposition zone to allow the component to form a perovskite structure on the surface; 7. The method of claim 1, further comprising:

8. The reduced pressure in the deposition zone is 1×10 －４ 8. The method according to claim 1 , wherein the temperature is lower than 1000 K.

9. 9. The method according to any one of claims 1 to 8, wherein the substrate has a multilayer structure comprising a transparent conductive oxide (TCO) layer and a preferred layer such as a hole transport layer or an electron transport layer.

10. the third evaporation source is disposed in an evaporation reactor in vapor communication with the deposition zone; 10. The method of any one of claims 1 to 9, wherein the method preferably includes the step of purifying the stream of evaporated components from the third evaporation source before it enters a deposition zone.

11. An apparatus (10) for producing a perovskite structure on a substrate surface (11), wherein the perovskite is ３ wherein component A is an organic molecule or a mixture of organic molecules, or A is cesium, potassium and / or rubidium, or a mixture of organic molecules and cesium, potassium and / or rubidium, component B is lead and / or tin, and component X is a halide; The apparatus comprises a vacuum chamber (12) with a substrate inlet (14) and a substrate outlet (16); the vacuum chamber comprises at least one deposition zone (18), in which at least a first evaporation source (20) and a second evaporation source (22) of components are disposed, the first evaporation source (20) comprising components A-X, and the second evaporation source (22) comprising components B-X; a third supply source is provided, the third supply source being a third evaporation source (24) comprising component A as a salt provided in the deposition zone (18) or in an evaporation reactor (26) in vapor connection with the deposition zone of the vacuum chamber, or the third supply source being an external supply source (28) containing a gas comprising component A provided in vapor connection with the deposition zone, the salt comprising an organic molecule or a mixture of organic molecules as a cation and an anion other than a halide, the gas contained in the external supply source (28) comprising formamidine, formamidinium, methylammonium or methylamine; The apparatus (10) includes a vacuum chamber (12) and an optional evaporation reactor (26) each comprising a heating device (29) configured to separately heat evaporation sources at reduced pressure to evaporate components and produce a stream of the components, the vacuum chamber configured to contact the stream with a substrate surface.

12. The apparatus of claim 11, configured to allow one or more substrates to be automatically moved into and out of the vacuum chamber via the substrate inlet (14) and the substrate outlet (16), respectively.

13. 13. An apparatus according to claim 11 or 12, configured for the in-line continuous production of perovskite structures on a substrate surface.

14. 14. The apparatus according to any one of claims 11 to 13, wherein the third evaporation source (24) is disposed within the evaporation reactor (26), and the apparatus preferably comprises a purification device (30) configured to purify vaporized components from the third evaporation source before they enter the deposition zone.

15. 12. The apparatus of claim 11, wherein an external source (28) containing a gas comprising component A is provided in vapor connection with the deposition zone, the apparatus preferably comprising a purification device (31) configured to purify the gas before it enters the deposition zone.

16. 16. The apparatus of claim 11, further comprising at least one detector (32) and a control unit (34) operably connected to the at least one detector (32), wherein the at least one detector (32) is configured to detect or measure at least one characteristic of the apparatus and send a signal indicative of the at least one characteristic to the control unit (34), and the control unit (34) is configured to control at least one of the heating device (29), pressure device (36), or flow control device for the evaporation reactor (26) or the external source (28).

17. 17. The apparatus of claim 16, wherein the detector (32) is a quartz crystal microbalance rate sensor.

18. 11. The method according to any one of claims 1 to 10, wherein the flow of components is monitored using at least one suitable detector located in the deposition zone, preferably by using one or more quartz crystal flow detectors or mass spectrometry.

19. 11. The method of any one of claims 1 to 10, wherein components of at least the first evaporation source, the second evaporation source and preferably also the third evaporation source are co-evaporated.

20. 11. The method of claim 1, wherein the substrate has a temperature that is lower than the temperature of the flow components.

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