Methods for perovskite device processing via vapor transport deposition

Abstract

Structures and methods for fabricating photovoltaic devices by forming perovskite layers and perovskite precursor layers using vapor transport deposition (VTD) are described.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This is an international application filed on February 19, 2021, under the authority of the Patent Cooperation Treaty, which claims the benefit of U.S. Provisional Application No. 62 / 978,760 filed on February 19, 2020, and is incorporated herein by reference. Technical Field

[0003] The present description relates generally to photovoltaic devices, and more particularly, to forming perovskite absorber layers and precursor layers for fabricating photovoltaic devices. Background Art

[0004] Photovoltaic devices generate electricity by converting light into electricity using semiconductor materials that exhibit the photovoltaic effect. Perovskites are a class of materials that can form the active layer in photovoltaic devices. Perovskite compounds have an ABX3 structure, where A and B are cations and X is a halogen. Some lead halide and tin halide perovskite compounds have been studied for use in photovoltaic devices. In these structures, the A site can be composed of organic methylammonium (MA), formamidine (FA), or inorganic cesium (Cs + ) or rubidium (Rb + ) cations. The B site can be lead (Pb +2 ) or tin (Sn +2 ) cations. And the X site can be occupied by a halogen, such as iodine (I - ), bromine (Br - ) or chlorine (Cl - ). In a photovoltaic device, the perovskite material is positioned in contact with and between negative and positive charge transport layers.

[0005] Although perovskites are promising materials, efficient, reliable, and scalable production methods are lacking. Known methods for producing perovskites include vacuum evaporation, spraying, or spin coating from solutions of compositions or precursors. Methods may include single-step and multi-step processes. Known methods for producing perovskite materials have significant barriers to use in manufacturing.

[0006] For example, vacuum evaporation requires a high vacuum, with pressures typically below 1x10 -4 mbar (0.01 Pa). Accurately controlled co-evaporation with multiple fluxes is challenging and expensive to transfer to large area manufacturing. The low pressures required are not well suited for efficient large-scale manufacturing, coatings of uniform thickness are difficult to achieve over large areas, and it is also relatively inflexible, often precluding the use of specific compositions, such as formamidinium iodide (FAI), due to concerns related to corrosion damage to equipment used in high vacuum.

[0007] Solution-based methods also have disadvantages. Perovskite compounds have the ability to self-assemble and crystallize, which is advantageous because low-temperature solution processing is possible. However, the crystallization rate is very high and can be difficult to control, making it difficult to make dense and uniform films without roughness and irregularities.

[0008] The method of preparing perovskite materials may include sequential coating to form a metal halide film, followed by applying an organic halide solution on the metal halide film to form a laminate of BX2 and AX films, and then reacting the two films to form an ABX3 structure. Although the two-step method has shown some improvements, the solution-based layer deposition process results in uneven layer thickness and can lead to incomplete reaction of the film. Using established methods, the resulting film has unpredictable quality, poor uniformity on surfaces greater than a few centimeters, and may be too rough and irregular to be used in effective photovoltaic devices. In the spray coating method, the solvent may produce unwanted by-products, limit the choice of compounds, and increase drying and film formation time. Spin coating is impractical for large-scale use, and it produces uneven layers on areas greater than a few square centimeters. Summary of the invention

[0009] It would be advantageous to provide improved methods, systems, and structures for efficient and scalable large-area fabrication of thin layers of perovskite absorbers and perovskite precursors with uniform thickness, high production speed, low cost, and excellent film quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The embodiments described in the drawings are illustrative and exemplary in nature and are not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, wherein like reference numerals represent the same or corresponding parts throughout the several views.

[0011] Figure 1 A vapor transport deposition (VTD) system is schematically depicted.

[0012] Figure 2 Schematically depicts Figure 1 Cross-sectional view of a VTD system.

[0013] Figure 3 An abstraction of the perovskite lattice structure of an example material is shown.

[0014] Figure 4 Embodiments of photovoltaic devices are schematically depicted.

[0015] Figure 5 Embodiments of photovoltaic devices are schematically depicted.

[0016] Figure 6 A flow chart of an example method is shown.

[0017] Figure 7 Example precursor layers are shown.

[0018] Figure 8 Example precursor layers are shown.

[0019] Fig. 9 Example precursor layers are shown.

[0020] Fig.10 Example precursor layers are shown.

[0021] Figures 11A-11B Example precursor layers and corresponding perovskite layers are shown.

[0022] Fig.12 Shown is an SEM image of a perovskite layer formed by the described method.

[0023] Fig.13 The absorbance of the perovskite layer at a given wavelength is shown.

[0024] Fig.14 Shown is the light transmission measurement of the perovskite layer.

[0025] Fig.15 Shown is an X-ray diffraction measurement of a perovskite layer.

[0026] Fig.16 Current-voltage measurements with reverse sweep on a perovskite device are shown.

[0027] Fig.17 A cross-sectional SEM image of a perovskite device is shown.

[0028] Fig.18 A cross-sectional SEM image of a perovskite device is shown.

[0029] The patent or application file may contain at least one drawing and / or one or more photographs executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the U.S. Patent Office upon request and payment of the necessary fee. DETAILED DESCRIPTION

[0030] Embodiments provide a perovskite precursor layer of a metal halide and a method for forming a perovskite precursor layer by vapor transport deposition (VTD). The perovskite precursor layer formed by the described method has improved thickness uniformity, density and process throughput. The perovskite layer produced by the method has improved properties, including: particle size, complete precursor conversion, improved thickness uniformity, and reduction or absence of bubbles and shunt defects. A method for converting a precursor layer into a perovskite layer is also provided. Generally, the photovoltaic device provided herein may include a partially formed or fully formed photovoltaic module. Perovskite precursor layers, partially formed photovoltaic structures and photovoltaic devices, and various embodiments of systems and methods for forming layers, structures and devices will be described in more detail herein.

[0031] Photovoltaic devices can contain several material layers deposited sequentially on a substrate. Vapor deposition can be used to deposit layers on a substrate. A physical vapor deposition technique for semiconductor material deposition is called vapor transport deposition (VTD). VTD has been established as a reliable technique for quickly and uniformly depositing thin film II-VI type semiconductor materials as thin solid film layers on a substrate. Although VTD has been established for use with some materials, such as II-VI type semiconductor materials, it has not yet been established for use with perovskite materials or to form perovskite precursor layers.

[0032] The VTD process can be performed at higher pressures than many other physical vapor deposition techniques. For example, vacuum thermal evaporation has been used to produce perovskite materials; however, such methods may require pressures below 10 -5 The VTD process can be carried out at a pressure of 0.1 Torr or higher, thereby requiring the use of equipment that is not well suited for high-throughput manufacturing. Such equipment can also eliminate the use of reagents that may cause corrosion, such as some halide vapors. Advantageously, the VTD process can be carried out at a pressure of 0.1 Torr or higher.

[0033] U.S. Patent 5,945,163 describes an example of a known VTD system. In a VTD system as shown in U.S. Patent 5,945,163, a semiconductor material in powder form is continuously supplied to the interior of a permeable vaporization chamber with the aid of a carrier gas. The vaporization chamber is heated to a high temperature sufficient to vaporize the powder, wherein the vapor passes through the permeable wall of the vaporization chamber. The vapor is then directed toward a substrate by a distributor, and the substrate moves through one or more holes of the distributor, which direct the vapor toward the substrate. The vapor condenses as a thin film on the surface of the substrate stack. The substrate stack includes a substrate material and a layer previously formed on the substrate.

[0034] The VTD system may include one or more of the following: a powder delivery unit, a powder vaporizer, a vapor distributor, and a vacuum deposition unit. A VTD powder vaporizer is typically designed to vaporize or sublimate raw material powder into a gaseous form. In some powder vaporizers, the raw material powder from the powder delivery unit is combined with a carrier gas and injected into a vaporizer shaped as a permeable heated cylinder. The material is vaporized in the cylinder, and the vaporized material diffuses through the permeable wall of the vaporizer into the vapor distributor. The distributor surrounds the vaporizer cylinder and directs the collected vapor toward an opening facing the substrate to deposit a thin film material on the substrate.

[0035] The VTD system can be adapted to use granular and / or powdered feedstocks. In some systems, the granular material is supplied through a hopper and a vibration-actuated material source is used, wherein vibrations introduced by a vibratory feeder cause the granular and / or powdered material to incrementally move from the hopper into an inclined channel. In this manner, the feedstock material is introduced into the feed tube along with one or more carrier gases from a carrier gas source.

[0036] Figure 1 An example of a vapor transport deposition system 20 for transporting and depositing materials onto a substrate or substrate stack 13 is shown, for example, the substrate can be a glass substrate for manufacturing thin film solar modules. Inert carrier gas sources 25 and 27 (e.g., helium (He), argon (Ar) and / or nitrogen (N2) sources) provide carrier gas to powder feeders 21 and 23, respectively, which contain powder or granular material. The gas transports the powder or granular material through injector ports 17, 19 on opposite ends of the vaporizer and distributor assembly 10. The vaporizer and distributor assembly 10 vaporizes the powder and / or granular material and distributes it for deposition onto the substrate stack 13.

[0037] Figure 2 It is along Figure 1 2-2 of the cross-sectional view of an example of a powder vaporizer and distributor assembly 10. The vaporizer 12 is configured as a heated tubular permeable member. It is composed of a resistive material that can be heated by an AC power source 29 and vaporizes a material powder that enters the vaporizer 12 through injector ports 17, 19 transmitted by a carrier gas. The distributor 15 is a housing heated by radiant heat from the vaporizer 12 and / or from another source. The housing of the distributor 15 surrounds the vaporizer 12 to capture material vapor that diffuses through the wall of the vaporizer 12. The semiconductor material vapor is directed by the distributor toward a slot or a series of holes 14 facing the substrate surface, and the substrate moves through the vaporizer and distributor assembly 10. More detailed examples of VTD systems of the type shown can be found in, for example, U.S. Patent Nos. 5,945,163, 5,945,165, 6,037,241, 7,780,787 and 8,382,901.

[0038] The temperature for VTD deposition can be in the range of about 200°C to about 1200°C. The vaporizer 12 can be formed as a heatable tubular permeable member formed of graphite or silicon carbide (SiC). The distributor 15 can be formed of a tube sleeve of a ceramic material (e.g., mullite). The vapor deposition occurs within a housing that contains a substrate transport mechanism, such as a driven roller. Ceramic sheets can also be used as thermal shields within the housing.

[0039] The VTD processing system can process a substrate (e.g., a glass sheet or a glass sheet coated with one or more thin films) for depositing a material. The system can include a housing defining a processing chamber in which the material is deposited on the substrate. The housing can include an entry station and an exit station. The entry station and the exit station can be configured as a vacuum lock or a gap seal through which the substrate enters and exits the processing chamber. The interior of the housing can be heated to a desired processing temperature and maintained at a processing pressure.

[0040] The VTD processing system may include a distributor assembly. The distributor assembly may be located above the conveyor to deposit material on the upward facing surface of the substrate. The conveyor may be a roller type, including rollers that support the downward facing surface of the substrate to convey the substrate during processing. The distributor assembly may be used with a vacuum drawn in the processing chamber, for example, in the range of about 0.1-50 Torr or about 10-6600 Pa. Therefore, the processing system may include a suitable exhaust pump for exhausting the processing chamber of the housing initially and continuously thereafter to remove carrier gas and secondary gas.

[0041] The embodiment of the distributor assembly may include a manifold, at least one vaporizer and at least one heater. The distributor assembly may include a manifold, which is configured to distribute semiconductor vapor along a steam curtain. The vaporizer may be supported on the manifold, attached to the manifold or otherwise communicated with the manifold fluid, and may be configured to vaporize powder or granular material for deposition. The heater may also be supported on the manifold, attached to the manifold or otherwise communicated with the manifold heat, and may be configured to heat at least a portion of the manifold. The manifold may generally include at least one slot or nozzle ("nozzle" may also be referred to as "jet"), which may be configured to guide vaporized semiconductor material to a substrate passing through, and the substrate may be transmitted along the path below the distributor assembly on a rolling conveyor or the like.

[0042] In some embodiments, the distributor assembly allows large-scale deposition by providing a vapor curtain greater than 1 m in size. In some embodiments, the vapor curtain width is between 1-2 m, or about 1.2 m. In some embodiments, the distributor assembly achieves a deposition rate of about 0.5 microns per second, about 1.0 microns per second, or about 1.5 microns per second.

[0043] The manufacture of photovoltaic devices may include sequentially arranging functional layers or layer precursors in a layer "stack" by one or more deposition processes, including but not limited to sputtering, spraying, evaporation, molecular beam deposition, pyrolysis, close space sublimation (CSS), pulsed laser deposition (PLD), chemical vapor deposition (CVD), electrochemical deposition (ECD), atomic layer deposition (ALD) or vapor transport deposition (VTD). In some embodiments, VTD may be preferred due to higher throughput speed and quality.

[0044] The fabrication of the photovoltaic device may further include selectively removing portions of certain layers of the layer stack, for example by scribing, to divide the photovoltaic device into a plurality of photovoltaic cells.

[0045] Reference Figure 3 , perovskite compounds have an ABX3 structure, where A and B are cations and X is a halogen anion. Specific materials and compounds for use in photovoltaic devices have been studied. In these perovskite structures, the A site can be occupied by one or more of MA, FA, Cs or Rb. The B site can be occupied by one or more of Pb, Sn or Ge. And the X site can be occupied by one or more of I, Br or Cl.

[0046] Organic-inorganic or inorganic metal halide perovskite materials can be used to absorb light energy in photovoltaic devices. In photovoltaic devices, the perovskite material is positioned in contact with and between negative and positive charge transport layers. Perovskite photovoltaic devices can be configured in a NIP or PIN orientation, with the negative or positive charge transport layer facing the light incident side of the device.

[0047] Figure 4 An example device structure of a perovskite photovoltaic device is shown. In the depicted example, the negative charge transport layer is close to the light incident side of the device.

[0048] Reference Figure 4 , schematically depicting an embodiment of a photovoltaic device 100. The photovoltaic device 100 can be configured to receive light and convert the light into an electrical signal, for example, photons can be absorbed from the light and converted into an electrical signal via the photovoltaic effect. Therefore, the photovoltaic device 100 can define an energy, light incident or front side 102, which is configured to be exposed to a light source (e.g., the sun). The photovoltaic device 100 can also define an opposite side 104 that deviates from the light incident side, for example, by multiple material layers. It should be noted that the term "light" can refer to various wavelengths of the electromagnetic spectrum, such as, but not limited to, wavelengths in the ultraviolet (UV), infrared (IR), and visible portions of the electromagnetic spectrum. As used herein, "sunlight" refers to light emitted by the sun.

[0049] Photovoltaic device 100 can include multiple layers arranged between the light incident front side and the opposite side 104. As used in this article, the term "layer" refers to the thickness of the material provided on the surface. Each layer can cover all or any part of the surface. In some embodiments, the layers of photovoltaic device 100 can be divided into photovoltaic cell arrays. For example, photovoltaic device 100 can be scribed according to multiple continuous scribe lines and multiple parallel scribe lines.

[0050] The layers of the photovoltaic device 100 may include a substrate 110 configured to facilitate transmission of light into the photovoltaic device 100. The substrate 110 may be disposed on a front side 102 of the photovoltaic device 100. The substrate 110 may have a first surface 112 that substantially faces an energy side of the photovoltaic device 100 and a second surface 114 that substantially faces an opposite side 104 of the photovoltaic device 100. One or more material layers may be disposed between the first surface 112 and the second surface 114 of the substrate 110.

[0051] The substrate 110 can be substantially transparent. In some embodiments, the substrate comprises a substantially transparent material, such as glass. Suitable glass can include soda-lime glass, glass with reduced iron content, or glass with about 90% transmittance. Optionally, the substrate 110 can include a performance coating applied to form an exterior or light-facing surface. The performance coating can be configured to interact with light or improve the durability of the substrate 110, such as, but not limited to, an anti-reflective coating, an anti-fouling coating, or a combination thereof.

[0052] The photovoltaic device 100 may optionally include a barrier layer 130 configured to mitigate diffusion of contaminants from the substrate 110 that may cause degradation or delamination. The barrier layer 130 may have a first surface 132 that substantially faces the front side 102 of the photovoltaic device 100 and a second surface 134 that substantially faces the opposite side 104 of the photovoltaic device 100. In some embodiments, the barrier layer 130 may be provided adjacent to the substrate 110. For example, the first surface 132 of the barrier layer 130 may be provided on the second surface 114 of the substrate 100. As used herein, the phrase "adjacent to" refers to two layers being arranged adjacently and without any intervening material between at least a portion of the layers.

[0053] Typically, barrier layer 130 can be substantially transparent, thermally stable, have a reduced number of bubbles, and have sodium blocking capabilities as well as good adhesion characteristics. Alternatively or additionally, barrier layer 130 can be configured to apply color suppression to light. Barrier layer 130 can include one or more layers of suitable materials, including but not limited to tin oxide, silicon dioxide, aluminum-doped silicon oxide, silicon oxide, silicon nitride, or aluminum oxide. Barrier layer 130 can have any suitable thickness defined by first surface 132 and second surface 134, including, for example, in one embodiment, greater than about 1000 mm. In another embodiment, greater than about Or in yet another embodiment less than about

[0054] The photovoltaic device 100 may include a transparent electrode layer 140 configured to provide electrical contact for transmitting charge carriers generated by the photovoltaic device 100. The transparent electrode layer 140 may have a first surface 142 substantially facing the energy side of the photovoltaic device 100 and a second surface 144 substantially facing the opposite side 104 of the photovoltaic device 100. In some embodiments, the transparent electrode layer 140 may be provided adjacent to the barrier layer 130. For example, the first surface 142 of the transparent electrode layer 140 may be provided on the second surface 134 of the barrier layer 130. Typically, the transparent electrode layer 140 may be formed by one or more layers of n-type semiconductor material that is substantially transparent and has a wide bandgap. Specifically, the wide bandgap may have a greater energy value compared to the photon energy of the light, which may mitigate undesirable light absorption. The transparent electrode layer 140 may include one or more layers of suitable materials, including but not limited to tin dioxide, doped tin dioxide (e.g., F-SnO2), indium tin oxide, or cadmium stannate.

[0055] The photovoltaic device 100 may include an electron transport layer (ETL) 150. The electron transport layer (ETL) may also be referred to as a negative charge transport layer, an n-type contact, an e - Selective contact or electron selective layer. It can be positioned to contact a transparent electrode used as an anode. The ETL 150 can have a first surface 152 substantially facing the front side 102 of the photovoltaic device 100 and a second surface 154 substantially facing the opposite side 104 of the photovoltaic device 100. In some embodiments, the ETL 150 can be provided adjacent to the transparent electrode layer 140. For example, the first surface 152 of the ETL 150 can be provided on the second surface 144 of the transparent electrode layer 140. The ETL 150 can have any suitable thickness between the first surface 152 and the second surface 154, including, for example, greater than about 2nm in one embodiment, between about 10nm-about 80nm in another embodiment, or between about 15nm-about 60nm in another embodiment. The ETL can include one or more layers of suitable materials, including but not limited to PCBM (phenyl-C61-butyric acid methyl ester), C60, BCP (bathocuproine), lithium fluoride (LiF) or metal oxides (e.g., TiO2, ZnO, SnO x , ZnSnO4, or SrTiO3). In some embodiments, ETL 150 comprises tin oxide (SnO2).

[0056] The partially formed device including substrate 110 , ETL 150 , and layers therebetween may be referred to as substrate stack 113 .

[0057] The photovoltaic device 100 may include an absorber layer 160 comprising a perovskite material configured to cooperate with adjacent layers and form a PIN junction within the photovoltaic device 100. Thus, absorbed photons of light may release electron-hole pairs and generate a flow of carriers, which may generate electricity.

[0058] Lead halide and tin halide perovskite compounds can be used in the absorber layer of photovoltaic devices. Metal halide perovskite compounds have an ABX3 structure, where A and B are cations and X is a halogen anion. In an example, the A site can be occupied by one or more organic or inorganic cations. For example, the A site can be composed of one or more of the following: methylammonium (MA), formamidine (FA), cesium (Cs) or rubidium (Rb) cations. The B site can be occupied by one or more metals, such as lead (Pb) or tin (Sb). And the X site can be occupied by one or more halogens, such as iodine (I), bromine (Br) or chlorine (Cl). The perovskite absorber layer can be formed by selecting one or more A-type cations or AX-type compounds and reacting them with one or more BX compounds. Metal halide materials suitable for use as BX compounds in the perovskite compound forming the absorber layer include iodides, bromides and / or chlorides combined with metals, alkali metals and / or combinations thereof. In some embodiments, the BX material is a Group 14 metal salt. Metal halides or BX materials suitable for use in perovskite compounds include, but are not limited to, lead iodide (PbI2), cesium iodide (CsI), lead bromide (PbBr2), cesium bromide (CsBr), cesium lead iodide (CsPbI3), cesium tin iodide (CsSnI3), lead chloride (PbCl2), tin iodide (SnI2), tin bromide (SnBr2) and / or tin chloride (SnCl2). In a photovoltaic device, the absorber layer of the perovskite material can be positioned in contact with and between the negative charge transport layer and the positive charge transport layer.

[0059] The absorber layer 160 may have a first surface 162 substantially facing the energy side of the photovoltaic device 100 and a second surface 164 substantially facing the opposite side 104 of the photovoltaic device 100. The thickness of the absorber layer 160 may be defined between the first surface 162 and the second surface 164.

[0060] In example devices, the absorber layer 160 may have a thickness between about 150 nm and 10,000 nm, such as between 500 nm and 10,000 nm in embodiments, between 1,000 nm and 7,000 nm in embodiments, between 200 nm and 6,000 nm in embodiments, between 300 nm and 3,000 nm in embodiments, between 400 nm and 2,000 nm in embodiments, between 400 nm and 1,500 nm in embodiments, or between 1,500 nm and 4,000 nm in another embodiment. Figure 4 In the embodiment shown, the absorber layer 160 is adjacent to the ETL 150 and adjacent to the hole transport layer.

[0061] The hole transport layer (HTL) 180 may also be referred to as a positive charge transport layer, a p-type transport layer, a hole transport material, or a hole transport layer. + The HTL 180 is a layer of a photosensitive conductive layer 180 that is provided adjacent to the absorber layer 160. The HTL 180 may have a first surface 182 that is substantially facing the front side 102 of the photovoltaic device 100 and a second surface 184 that is substantially facing the opposite side 104 of the photovoltaic device 100. The thickness of the HTL 180 may be defined between the first surface 182 and the second surface 184. The thickness of the HTL 180 may be between about 5 nm and about 200 nm, for example, in one embodiment, between about 10 nm and about 50 nm. In the illustrated embodiment, the HTL 180 is provided adjacent to the absorber layer 160. For example, the first surface 182 of the HTL 180 is provided on the second surface 164 of the absorber layer 160.

[0062] In some embodiments, the HTL 180 may include metal oxides, polymers, small molecules, or organic hole transport materials. In some embodiments, the hole transport material may include one or more of the following: nickel oxide (NiO x ), copper thiocyanate (CuSCN), copper phthalocyanine (CuPc), tungsten oxide (WO3), copper iodide (CuI) or copper oxide (CuO x In some embodiments, HTL 180 may be composed essentially of nickel oxide (NiO x). In some embodiments, HTL 180 may include an organic compound such as 2,2',7,7'-tetrakis[N,N-di(4-methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD). The CAS number of Spiro-OMeTAD is 207739-72-8. In some embodiments, HTL 180 may include one or more of the following: Spiro-OMeTAD, PTAA (poly-triarylamine or poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine]), PEDOT:PSS (poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)), P3HT (poly(3-hexylthiophene-2,5-diyl)), P3HT-COOH (poly[3-(6-carboxyhexyl)thiophene-2,5-diyl]), or poly-TPD (4-butyl-N,N-diphenylamine homopolymer).

[0063] The photovoltaic device 100 may include a conductive layer or back electrode 190. The conductive layer may have a first surface 192 that substantially faces the energy side of the photovoltaic device 100 and a second surface 194 that substantially faces the opposite side 104 of the photovoltaic device 100. In some embodiments, the back electrode 190 may be provided adjacent to the HTL 180. For example, the first surface 192 of the conductive layer may be provided on the second surface 184 of the HTL 180. The conductive layer may include a conductive material, such as one or more layers of a nitrogen-containing metal, silver, nickel, copper, aluminum, titanium, palladium, chromium, molybdenum, gold, etc. Examples of nitrogen-containing metal layers may include aluminum nitride, nickel nitride, titanium nitride, tungsten nitride, selenium nitride, tantalum nitride, or vanadium nitride.

[0064] The photovoltaic device 100 may include a back support 196 configured to cooperate with the substrate 110 to form a housing for the photovoltaic device 100. The back support 196 may be disposed on the opposite side of the photovoltaic device 100. For example, the back support 196 may be formed adjacent to the back electrode 190. The back support 196 may include any suitable material, including, for example, glass (e.g., soda-lime glass). In some embodiments, the encapsulation layer may also serve as the back support 196.

[0065] The photovoltaic device 100 may optionally include one or more interlayers and / or one or more buffer layers. The buffer layer may be configured to provide an insulating layer between adjacent layers. The buffer layer may include a material having a higher electrical resistance than the adjacent layers and may include, but is not limited to, intrinsic tin dioxide, magnesium zinc oxide (e.g., Zn 1-x Mg xThe buffer layer may be a layer of a plurality of semiconductor layers. ...

[0066] In some embodiments, the NIP structure is inverted to a PIN orientation, wherein the positive charge transport layer is closer to the front side relative to the negative charge transport layer. In some embodiments, selected layers including the HTL, the perovskite absorber, and the ETL are included in a tandem device. In a method for forming a tandem device, a method for forming a perovskite layer may include forming the perovskite layer on a contact layer of a substrate stack, wherein the substrate stack includes a cell stack and a tunnel junction.

[0067] Figure 5 An example device 200 is shown with a PIN orientation. The layers are Figure 4 Same as described, but can be Figure 5 The partially formed device (including substrate 110 , HTL 180 , and layers therebetween) may be referred to as substrate stack 213 .

[0068] The layer of the substrate stack opposite the substrate can be referred to as the first contact layer or the first charge transport layer. The first charge transport layer of the substrate stack is equivalent to the HTL in a device with a PIN orientation or the ETL in a device with a NIP orientation. As used herein, the substrate stack (13, 113, 213) does not include an absorber layer. In a fully formed device, the absorber layer is arranged between the first charge transport layer and the second charge transport layer, the second charge transport layer having a charge opposite to the first charge transport layer.

[0069] Now turn Figure 6 , an overview of an example process flow for forming a photovoltaic device is shown.

[0070] A substrate stack 610 is formed and prepared. The substrate may be formed of a transparent support (e.g., glass) with a transparent electrode and a first charge transport layer (e.g., HTL or ETL) on the transparent support. Optionally, the substrate stack may further include a first scribe line set and one or more additional layers, such as a buffer layer, a high resistance layer, or an anti-reflection layer.

[0071] The substrate stack may optionally be cleaned 620. The substrate stack may be cleaned with a fluid such as a solvent or a gas. For example, the substrate stack may be cleaned using UV ozone or plasma.

[0072] By VTD, a first perovskite-forming composition (e.g., lead halide or tin halide) is deposited onto the electron transport material of the substrate stack to form a precursor layer 630. To deposit the first perovskite-forming composition, the substrate may be conveyed into a deposition chamber. The temperature and pressure in the deposition chamber may be controlled during the deposition process.

[0073] In an example process, the deposition chamber temperature is in the range of 20°C-150°C and the pressure is in the range of 0.1 Torr-5 Torr. The deposition chamber may have an atmosphere containing an inert carrier gas or a combination of air and an inert gas. The first source material may include a metal halide source, such as a lead halide or a tin halide, heated to a temperature in the range of 375°C-550°C. The first source material may be transported to the substrate using a carrier gas. The carrier gas may be inert. The carrier gas may contain one or more of helium, nitrogen, or argon. The first precursor layer may be PbI2, SnI2, PbBr2, SnBr2, or a combination thereof. The vaporized source material carried by the carrier gas may pass through a manifold that is positioned close to the substrate path. When the substrate is conveyed through the manifold, the manifold guides the vaporized source material to be deposited substantially perpendicular to the substrate path across the width of the substrate. The substrate may be continuously conveyed along the substrate path so that the first charge transport layer adjacent to the substrate stack is deposited in a continuous layer with a substantially uniform thickness of the first precursor material. In some embodiments, the first perovskite-forming composition is deposited simultaneously along the width of the substrate to a thickness of 100-2000 nm. In an example, the substrate width is in the range of 1-2 meters.

[0074] The substrate stack with the precursor layer coating is then exposed to a second perovskite-forming precursor composition 640. The second precursor composition may include, for example, a liquid or vapor of MAI, FAI, and / or other perovskite-forming compounds.

[0075] The substrate stack having the first perovskite forming composition is exposed to a reactant comprising a second perovskite forming composition and annealed to react and convert the first precursor layer to a perovskite layer 650. The steps of providing the second perovskite forming precursor composition 640 and converting the first precursor layer to a perovskite layer 650 may be performed simultaneously or sequentially.

[0076] In an example, during the annealing process, the first precursor layer is in contact with the second perovskite-forming composition.

[0077] In an example, the first precursor layer is exposed to the second perovskite-forming composition by spraying the second precursor layer onto the first precursor layer.

[0078] In an example, the first precursor layer is exposed to the second perovskite-forming composition by depositing the second precursor layer by vapor transport deposition.

[0079] The annealing process may include controlling temperature, humidity, pressure, reactant concentrations, reactant exposure time, and heating duration. In some embodiments, one or more dopants may be incorporated during the annealing process.

[0080] In an example annealing process, a surface of a transfer plate having dimensions corresponding to the length and width of the substrate is coated with methylammonium iodide (MAI) dissolved in an isopropanol solvent and dried to evaporate the solvent. The transfer plate coated with MAI is positioned adjacent to a first precursor layer on the surface of the substrate stack, wherein the distance between the transfer plate and the precursor layer is in the range of 0.5-10 centimeters. The transfer plate is heated to a range of 75-125° C. over a period of 20-120 minutes, vaporizing the MAI from the transfer plate and exposing the first precursor layer to the MAI vapor. The annealing process may be performed in an annealing chamber.

[0081] After forming the perovskite material, the perovskite layer may optionally be passivated 660 .

[0082] A second charge transport layer 670, such as an ETL or HTL, having a charge opposite to that of the first charge transport layer is formed on the perovskite absorber layer. A diffusion barrier or a moisture barrier may be formed. The substrate stack having the perovskite layer and the HTL may be processed by additional processing steps 680. Additional processing steps may include one or more of the following: formation of additional layers, cleaning, scribing, encapsulation, or application of bussing connections. The substrate stack having the perovskite layer and the second charge transport layer may optionally be scribed, for example, by a laser to form additional scribing groups. A conductive layer or back electrode may be formed on the second charge transport layer. The substrate stack having the conductive layer may be scribed to form a back scribing group. An encapsulation layer may be applied over the completed layer stack. Buses or other electrical connections and back supports may be added to the device.

[0083] The intermediate structure of the perovskite photovoltaic device formed by the example method has a well-structured precursor layer before the precursor layer is annealed and converted into a perovskite absorber layer. This precursor layer structure produces a dense perovskite coating with a well-defined, contiguous, perovskite grain structure that facilitates reliable and efficient photovoltaic power conversion.

[0084] The first precursor layer includes a metal halide material, which is arranged in a layer above the charge transport layer. Metal halide materials suitable for perovskite compounds include iodides, bromides and / or chlorides combined with metals, alkali metals and / or combinations thereof. Metal halide materials suitable for use in perovskite compounds include, but are not limited to, lead iodide (PbI2), lead bromide (PbBr2), cesium bromide (CsBr), cesium lead iodide (CsPbI3), cesium tin iodide (CsSnI3), lead chloride (PbCl2), tin iodide (SnI2), tin bromide (SnBr2) and / or tin chloride (SnCl2).

[0085] Using the described method, a precursor layer with advantageous characteristics can be reliably and efficiently prepared using a process suitable for manufacturing photovoltaic panels. In order to promote efficient conversion, the deposited metal halide has a high porosity. Among other methods, a scanning electron microscope (SEM) can be used to produce a three-dimensional measurement, from which the void ratio can be determined to evaluate the porosity. The film prepared by the method may have a porosity of about 50%. In an example, the precursor layer has a porosity of about 50%. In an example, the precursor layer has a porosity in the range of 35%-65%, in the range of 40%-60% and / or in the range of 45%-55%.

[0086] The precursor layer may have a densely packed petal-like crystalline grain structure oriented such that the height of most of the petal-like crystalline grain structures substantially perpendicular to the surface of the substrate stack is substantially greater than the cross-sectional grain width parallel to the substrate stack. The precursor layer may have a lawn-like layer of a substantially uniform and dense crystalline grain structure. The layer may provide sufficient material to produce an absorber layer without bubbles or gaps. The layer may provide a favorable surface to volume ratio to promote complete reaction with the second precursor layer without unreacted metal halide material. In an example precursor layer, at least one-third of the particles of the precursor layer have a height in the range of 200 nm-500 nm and a cross-sectional grain width size of less than 50 nm.

[0087] In an example, the precursor layer comprises a plurality of lead iodide crystal grain structures having a height perpendicular to the surface of the substrate stack and a width parallel to the surface of the substrate stack, and at least a quarter of the grain structures of the precursor layer have a height in the range of 200 nm-700 nm and a width less than 100 nm.

[0088] PbI at selected temperatures 2 VTD.

[0089] A set of sample substrate stacks are prepared. The sample substrate stacks are then placed in a VTD chamber. Lead iodide (PbI2) is used as the source material for the first precursor layer. The raw material is heated to a selected temperature of about 300°C, 350°C, 400°C, 450°C, 500°C and 600°C. The chamber temperature is maintained at a temperature lower than the heated source material. The substrate temperature is at or below the chamber temperature. A carrier gas comprising helium guides the vaporized PbI2 toward the substrate. PbI2 is deposited to a thickness of 100-1000nm. The resulting film is qualitatively evaluated. It is found that the quality of the film produced in this example has a more favorable quality at a temperature closer to the middle of the test range.

[0090] Additional temperature tests were conducted for a range of pressure levels and carrier gas flow rates. The experimental results show that layers were formed by depositing metal halide sources heated to a temperature in the range of 375°C-550°C in a deposition chamber having a pressure in the range of 0.1-2.0 Torr and using a carrier gas containing a noble gas. Under the experimental conditions, the layer quality was improved for layers produced by sources heated to a temperature in the range of 400°C-525°C.

[0091] PbI at selected pressure and deposition rate 2 VTD.

[0092] Steering Figure 7-10 , a precursor film is prepared at a selected pressure and deposition rate. A set of sample substrate stacks is prepared. Each sample substrate stack is placed in a VTD chamber. Lead iodide (PbI2) powder is used as a source material for the first perovskite precursor layer. The source material is heated to above 400°C. The chamber temperature is maintained in the range of about 25°C-100°C. The substrate temperature is at or below the chamber temperature.

[0093] Four conditions were tested, Group A corresponding to Figure 7 The examples shown in ; Group B corresponds to Figure 8 The example shown in ; Group C corresponds to Fig. 9 The example shown in ; and group D corresponds to Fig.10The example shown in . A carrier gas comprising helium directs vaporized PbI2 toward a substrate. PbI2 is deposited in a layer consisting mainly of PbI2 to a thickness range of 100-1000 nm. In groups A and B, the chamber pressure is maintained at about 1.5 Torr. In groups C and D, the chamber pressure is maintained at about 0.3 Torr. In groups A and C, the carrier gas flow rate is about 110 sccm (sccm-standard cubic centimeters per minute), and the deposition rate is about 0.25 μm / minute (250 nm / minute). In groups B and D, the carrier gas flow rate is about 110 sccm, and the deposition rate is about 0.04 μm / minute (40 nm / minute). After the PbI2 layer is deposited, the substrate is allowed to cool to room temperature before the next processing step.

[0094] Figure 7-10 SEM images of the precursor layer formed under each set of conditions (A, B, C, and D) are shown. Figure 7-10 The upper panel in each figure shows an image of the surface of the precursor layer with a scale bar of 1 micrometer (1000 nm). Figure 7-10 The lower panel in each of the figures shows a cross-sectional image through the precursor layer and the underlying layer. Figure 8 The scale bar in the lower panel is 400 nm, and Figure 7 , Fig. 9 and Fig.10 The scale bar in the lower panel of the image is 500 nm. As can be seen in the images, the precursor layers formed in groups B, C and D exhibited a favorable grain structure of closely spaced petal-like crystalline grain structures, with group D showing a substantially upright orientation of the grains relative to the matrix stack. The resulting films exhibited good adhesion as confirmed by tensile testing.

[0095] PbI deposited by VTD 2 Annealed and converted to perovskite.

[0096] Fig.11A Four panels are shown from left to right, depicting SEM images of precursor layers corresponding to the above-mentioned groups AD, respectively. Fig. 11B Four panels from left to right are shown corresponding to Groups AD, respectively, and depict the perovskite layer after each precursor layer is converted to perovskite under substantially identical conditions of exposure to a reactant comprising a second perovskite-forming material and thermal treatment. Fig.11A and 11BThe scale bar of the images depicted in is 1 micrometer (1000 nm). In this example, the second perovskite-forming material comprises MAI, resulting in a MAPbI3 perovskite layer. It can be seen that the perovskite layer of Group A is non-contiguous and irregular, indicating a poor quality layer. The layer shown in Group D has characteristics indicating a high quality layer, which is regular, uniform, contiguous, and has large and similarly sized perovskite particles.

[0097] The materials produced by the method of group D form high quality perovskite absorber materials, which are further confirmed by high photoluminescence (PL) measurements.

[0098] Process parameters and resulting film quality.

[0099] Characteristics and factors associated with producing good film quality in perovskite layers include: pressure, temperature, humidity, material selection, crystal structure, particle size, adjacent layers, thickness and / or porosity. When a precursor layer exhibits high porosity or surface to volume ratio, subsequent exposure to a second precursor is enhanced, thereby producing a film in which the chemical reaction with the second precursor proceeds rapidly and simultaneously to completion. The described VTD system and method are particularly effective for controlling material deposition parameters, thereby providing a resulting layer with desired properties.

[0100] Fig.12 Images of a perovskite layer formed by the described method are shown. The converted perovskite particles are tightly packed and large, with no bubbles or gaps. The left panel shows a cross-sectional SEM with a scale bar of 400 nm. The right panel shows a top surface SEM image of the perovskite layer with a scale bar of 1 micron.

[0101] Now turn Figure 13-15 , shows the measurement of absorber quality. Fig.13 The wavelength absorbance of the absorbers formed by the described method is shown. Fig.14 Light transmission measurements of a perovskite layer on a fluorine-doped tin oxide (FTO)-coated glass substrate are shown. The position and sharp rise of the absorption edge are consistent with previously characterized perovskite layers. Fig.15 X-ray diffraction measurements of a perovskite layer with characteristic perovskite (PK) peaks are shown. The lack of peaks for PbI2 indicates that the conversion of the precursor layer to perovskite is complete and there is no significant measurable PbI2 residue.

[0102] Integrating perovskite films into functional devices. Fig.16 An example of current-voltage (IV) measurement by reverse sweep on a perovskite device with the following structure is shown: FTO / ETL / perovskite layer / HTL / Au back contact. The device achieves an efficiency greater than 13%.

[0103] Figure 17-18A cross-sectional SEM image of a perovskite device prepared by VTD of a PbI2 first precursor layer followed by wet conversion is shown. The thickness of the film is about 400 nm, and the average perovskite grain width is greater than 500 nm. Fig.17 and 18 Each has a scale bar of 500 nm.

[0104] Example - VTD of Cesium Bromide (CsBr)

[0105] A substrate stack is prepared and at least one sample substrate stack is transferred to a VTD chamber. A powder material comprising cesium bromide (CsBr) is used as a source material for a first perovskite precursor layer. The source material is heated to above 400°C. The chamber is maintained at a temperature in the range of 25°C-150°C and a pressure in the range of 0.1 Torr-2.0 Torr. A carrier gas is directed at a carrier gas flow rate in the range of 80 sccm-150 sccm through a manifold toward the surface of the substrate stack to deposit a precursor layer comprising cesium bromide on the substrate stack with a layer thickness in the range of 100-2000 nm. In some embodiments, the source material further comprises tin and / or lead.

[0106] Example - Cesium Tin Iodide (CsSnI 3 )

[0107] A substrate stack is prepared and at least one sample substrate stack is transferred into a VTD chamber. A powder material comprising cesium tin iodide (CsSnI3) is used as a source material for a first perovskite precursor layer. The source material is heated to above 400°C. The chamber is maintained at a temperature in the range of 25°C-150°C and a pressure in the range of 0.1 Torr-2.0 Torr. A carrier gas is directed at a carrier gas flow rate in the range of 80 sccm-150 sccm through a manifold toward the surface of the substrate stack to deposit a precursor layer comprising cesium tin iodide on the substrate stack with a layer thickness in the range of 100-2000 nm.

[0108] Example - Lead Bromide (PbBr 2 )

[0109] A substrate stack is prepared and at least one sample substrate stack is transferred into a VTD chamber. A powder material comprising lead bromide (PbBr2) is used as a source material for a first perovskite precursor layer. The source material is heated to above 400°C. The chamber is maintained at a temperature in the range of 25°C-150°C and a pressure in the range of 0.1 Torr-2.0 Torr. A carrier gas is directed at a carrier gas flow rate in the range of 80 sccm-150 sccm through a manifold toward the surface of the substrate stack to deposit a precursor layer comprising lead bromide on the substrate stack with a layer thickness in the range of 100-2000 nm.

[0110] A system with one or more processors can be used to complete the processing steps in manufacturing devices. According to the embodiments described herein, a processor means any device capable of executing machine-readable instructions. Therefore, each of the one or more processors can be a controller, an integrated circuit, a microchip, a computer, or any other computing device.

[0111] The one or more processors may be configured to execute logic or software and perform functions that control the relative movement of the system and the layer stack as well as the processing characteristics of the system (e.g., conveyor speed, temperature, pressure, and gas or material flow rate). In addition, the one or more processors may be communicatively coupled to one or more memory components that may store logic and / or inputs received by the one or more processors. The memory components described herein may be RAM, ROM, flash memory, a hard drive, or any device capable of storing machine-readable instructions.

[0112] As used herein, the term "communicatively coupled" means that a component can exchange data signals with another component, such as electrical signals via a conductive medium, electromagnetic signals via air, optical signals via an optical waveguide, etc.

[0113] Embodiments of the present disclosure include logic, the logic including machine-readable instructions or algorithms written in a programming language, the programming language including a machine language that can be directly executed by a processor, or an assembly language, object-oriented programming (OOP), scripting language, or microcode that can be compiled or assembled into machine-readable instructions and stored on a machine-readable medium. Alternatively, the logic or algorithm can be written in a hardware description language (HDL), such as logic implemented via a field programmable gate array (FPGA) configuration or an application-specific integrated circuit (ASIC) and its equivalents. Therefore, the logic can be implemented in any conventional computer programming language, as a pre-programmed hardware element, or as a combination of hardware and software components.

[0114] The distributor assembly and method described herein provide substantial uniformity of steam distribution. The distributor assembly provided herein can be scaled to coat large substrates, e.g., substrates having a size greater than or equal to about 1 m in length and / or width, between 0.5-2.0 m in length and width, or up to about 2 m in length and / or width.

[0115] According to the embodiments provided herein, the distributor assembly for the vapor transport deposition system may include a manifold, at least one vaporizer, at least one heater and a slot or nozzle in the manifold. The at least one vaporizer may be supported on the manifold, connected to the manifold, or in fluid communication with the manifold, and configured to vaporize a powder of a semiconductor material or a semiconductor precursor material. The slot or nozzle in the manifold may be configured to direct steam to a substrate passing through.

[0116] According to the embodiments provided herein, a method for performing vapor transport deposition (VTD) may include: vaporizing a powder source of material in a distributor assembly using a dedicated vaporizer, wherein the dedicated vaporizer is configured to selectively heat the powder source so as not to substantially heat other components of the distributor assembly; and depositing the vaporized semiconductor material onto a substrate moving through the distributor assembly.

[0117] According to any of the embodiments provided above, the distributor assembly is capable of simultaneously delivering uniform vaporization and distribution of steam along the width of a substrate stack having a width of 1.0-2.0 meters.The width may be measured across a dimension perpendicular to the edge and perpendicular to the conveying direction.

[0118] According to any of the embodiments provided above, the dispenser assembly can be configured to deposit material onto the substrate stack at a deposition rate between 0.05-1.75 microns / second. In an example, the deposition rate is at least 0.25 microns / second. In an example, the deposition rate is at least 0.5 microns / second. In an example, the deposition rate is at least 1 micron / second. In an example, the deposition rate is about 1.5 microns / second.

[0119] According to any of the embodiments provided above, the manifold may define a complete housing that houses the vaporizer and heater.

[0120] According to any of the embodiments provided above, the distributor assembly may include a plurality of slots or nozzles configured to direct steam onto a passing substrate.

[0121] According to the embodiments provided herein, a method for forming a perovskite precursor layer may include: providing a substrate stack in a deposition chamber, the substrate stack having a first charge transport layer on a first electrode; depositing a first perovskite-forming composition on the substrate stack in the deposition chamber by vapor transport deposition, by heating a source material to a temperature in the range of 375°C-550°C, using a carrier gas to direct vapor of a first perovskite-forming material toward the substrate stack in the deposition chamber, the deposition chamber having a pressure in the range of 0.1-2.0 Torr; and forming a first precursor layer having a thickness of 100-2000 nm.

[0122] According to the embodiments provided herein, an intermediate structure for a perovskite photovoltaic device may include: a first electrode; a first charge transport layer on the first electrode; and a precursor layer on the first charge transport layer, wherein the precursor layer has a thickness in the range of 100-2000 nm, a thickness deviation within the layer of less than 50%, and comprises at least one metal halide in a crystalline matrix having a porosity greater than 35%.

[0123] According to the embodiments provided herein, a method for forming a perovskite-based photovoltaic device may include: depositing a first charge transport layer onto a first electrode; depositing a first perovskite-forming composition on the charge transport layer by a VTD having a carrier gas under a vapor transport deposition (VTD) condition set to form a precursor layer; contacting the precursor layer with a second perovskite-forming composition, reacting the precursor layer with the second perovskite-forming composition, converting the precursor layer into a perovskite under an annealing condition set to form a photosensitive absorber layer comprising a perovskite material, depositing a second charge transport layer having an opposite polarity to the first charge transport layer onto the perovskite material; and depositing a conductive material onto the second charge transport layer to form a second electrode.

[0124] In some embodiments, the first perovskite forming composition may include a Group IV metal halide. In some embodiments, the first perovskite forming composition may include one or more of the following: lead halide and / or tin halide. In some embodiments, the first perovskite forming composition may include one or more of the following: lead iodide (PbI2), lead bromide (PbBr2), cesium bromide (CsBr), cesium lead iodide (CsPbI3), cesium tin iodide (CsSnI3), lead chloride (PbCl2), tin iodide (SnI2) and / or tin chloride (SnCl2).

[0125] In an example, the first perovskite-forming composition includes lead iodide.

[0126] In an example, the first perovskite-forming composition includes lead bromide.

[0127] In an example, the first perovskite-forming composition includes cesium bromide.

[0128] In some embodiments, the metal halide comprises one or more of: I, Br, or Cl.

[0129] In some embodiments, the metal halide comprises iodine and / or bromine.

[0130] In some embodiments, the metal halide comprises at least one Group IVA metal.

[0131] According to the embodiments provided herein, the precursor layer comprises at least one of: lead iodide (PbI2), lead bromide (PbBr2), cesium bromide (CsBr), cesium lead iodide (CsPbI3), cesium tin iodide (CsSnI3), lead chloride (PbCl2), tin iodide (SnI2), tin bromide (SnBr2) and / or tin chloride (SnCl2). In an example, the precursor layer comprises lead iodide (PbI2).

[0132] In some embodiments, the precursor layer comprises a plurality of grains wherein 30-100% of the grains have a size in at least one dimension having a length in the range of 200-800 nm.

[0133] In some embodiments, the VTD condition set includes: a deposition chamber temperature in the range of 20°C-150°C; a source material of a first perovskite-forming composition heated to a temperature in the range of 375°C-550°C; a deposition chamber atmosphere including an inert carrier gas; and a deposition chamber pressure in the range of 0.05 Torr-5.0 Torr. In some embodiments, the chamber pressure during the step of depositing the first precursor layer is in the range of 0.1-5.0 Torr, 0.1-2.0 Torr, 0.1-1.5 Torr, 0.25-1.5 Torr, 0.25-1.0 Torr, 0.25-0.75 Torr, or 0.25-0.50 Torr.

[0134] In an example, the source material of the first perovskite-forming composition comprises a powder.

[0135] In some embodiments, the source material is heated to a temperature in the range of 400° C. to 525° C. In an example, the source material is heated to a temperature in the range of 400° C.-500° C. In an example, the source material is heated to a temperature in the range of 450° C. to 525° C. In an example, the source material is heated to a temperature in the range of 400° C. to 475° C.

[0136] In some embodiments, the substrate stack in the deposition chamber has a temperature in the range of 20°C - 150°C.

[0137] In some embodiments, the carrier gas is inert. In some embodiments, the carrier gas comprises a noble gas. In an example, the carrier gas comprises helium. In an example, the carrier gas comprises argon. In an example, the carrier gas comprises nitrogen.

[0138] In an example, the first precursor layer is deposited by VTD, including a deposition rate in the range of 0.01-1.50 microns / minute, a deposition time in the range of 0.5-5 minutes, and produces a precursor layer with a thickness of 100-2000 nm. In some embodiments, the first precursor layer is deposited by VTD, including a deposition rate in the range of 0.05-1.00 μm / minute, 0.05-0.75 μm / minute, 0.05-0.50 μm / minute, or 0.01-0.35 μm / minute.

[0139] According to embodiments provided herein, an intermediate structure of a perovskite photovoltaic device may include a precursor layer on a first charge transport layer.

[0140] According to the embodiments provided herein, the thickness of the precursor layer is between 100 nm-2000 nm. In some embodiments, the thickness of the precursor layer is in the range of 200-1500 nm, in the range of 300-1200 nm, in the range of 300-900 nm and / or in the range of 350-800 nm. In some embodiments, the precursor layer has a thickness in the range of 200-1000 nm, 300-700 nm, 350-600 nm or 400-500 nm. In an example, the precursor layer thickness is in the range of 300-1200 nanometers.

[0141] In some embodiments, the precursor layer has a thickness variation within the layer of less than 50%, less than 40%, less than 30%, less than 20%, or less than 15%. In an example, the precursor layer has substantially no bubbles and has a minimum thickness of 100 nm throughout the precursor layer. In an example, the precursor layer has substantially no bubbles and has a minimum thickness of 200 nm throughout the precursor layer.

[0142] In some embodiments, the precursor layer comprises a plurality of metal halide crystal grain structures, wherein: the grain structures have a height perpendicular to the surface of the substrate stack and a width parallel to the surface of the substrate stack, and the average grain width is less than one third of the average grain height. In an example, the grain structures comprise lead iodide.

[0143] In some embodiments, the precursor layer has a porosity in the range of 35%-65%, in the range of 40%-60%, and / or in the range of 45%-55%. In an example, the porosity is greater than 40%.

[0144] In some embodiments, the second perovskite-forming composition includes at least one of a cesium (Cs) cation, a rubidium (Rb) cation, a methylammonium (MA) compound, and / or a formamidine (FA) compound.

[0145] In an example, the set of annealing conditions includes: an annealing chamber pressure in the range of 0.1 Torr-1000 Torr, an annealing time in the range of 1-90 minutes, a humidity in the range of 40%-60%, and an annealing chamber temperature in the range of 50° C.-200° C. In some embodiments, the pressure during the annealing step is in the range of 0.1-100.0 Torr, 0.1-20.0 Torr, 0.1-5.0 Torr, 0.1-2.0 Torr, or 0.25-1.5 Torr.

[0146] According to embodiments provided herein, the first charge transport layer for a photovoltaic device may comprise a hole transport layer or an electron transport layer, and the second charge transport layer may comprise an electron transport layer or a hole transport layer, provided that the first and second charge transport layers have opposite charge polarities.

[0147] According to the embodiments provided herein, a method for forming a perovskite-based photovoltaic device may include: depositing a first hole transport or electron transport layer onto a first electrode; depositing a first perovskite-forming composition comprising a lead halide or a tin halide onto a first hole transport or electron transport material by VTD under a vapor transport deposition (VTD) condition group to form a precursor layer; depositing a second perovskite-forming composition; under an annealing condition group, converting the precursor layer into a perovskite by reacting the precursor layer with the second perovskite-forming composition to form a photosensitive layer comprising a perovskite material on the first hole transport layer or the electron transport layer; depositing a second hole transport or electron transport layer having an opposite polarity to the first hole transport or electron transport layer onto the perovskite material; and depositing a conductive material onto the second hole transport or electron transport layer to form a second electrode.

[0148] In some embodiments, the VTD condition set includes: a chamber temperature in the range of 20° C.-150° C., an atmosphere comprising an inert carrier gas, a metal halide source heated to a temperature in the range of 375° C.-550° C., a deposition rate in the range of 0.10-1.00 microns / minute, and a pressure in the range of 0.1 Torr-5 Torr. In some embodiments, the precursor layer is deposited at a thickness of 400-500 nm or more, wherein the deposition duration is in the range of 0.5 minutes-5 minutes.

[0149] In some embodiments, a method of manufacturing a perovskite absorber layer of a photovoltaic device includes: providing an intermediate structure having a metal halide precursor layer formed from a first perovskite-forming composition; exposing the intermediate structure to a second perovskite-forming composition; and annealing the intermediate structure having the second perovskite-forming composition. In some embodiments, the second perovskite-forming composition comprises at least one of: a cesium (Cs) cation, a rubidium (Rb) cation, a methylammonium (MA) compound (I or Br), or a formamidine (FA) compound; the annealing condition set may include: a pressure in the range of 0.1 Torr-1000 Torr, an annealing duration in the range of 10 minutes-90 minutes, a humidity in the range of 45%-60%, and a temperature in the range of 50°C-150°C. In some embodiments, the step of exposing the intermediate structure to the second perovskite-forming composition comprises contacting the precursor layer with a vapor comprising the second perovskite-forming composition. In some embodiments, exposing the intermediate structure to the second perovskite-forming composition includes depositing a material comprising the second perovskite-forming composition in a layer above the precursor layer.

[0150] In some embodiments, the method produces a perovskite absorber layer having a thickness of about 400 nm, wherein the average perovskite particle size is greater than 500 nm in width. In some embodiments, the method produces a perovskite absorber layer having a thickness in the range of 200-800 nm. In some embodiments, the method produces a perovskite absorber layer having perovskite particles, the average perovskite particle width of the perovskite particles being greater than the average perovskite particle height. In some embodiments, the method produces a perovskite absorber layer substantially free of bubbles or gaps. In some embodiments, the method produces a perovskite absorber layer having a thickness greater than 200 nm. In some embodiments, the method produces a perovskite absorber layer having a thickness in the range of 200 nm-10000 nm. In some embodiments, the method produces a perovskite absorber layer having a thickness in the range of 200 nm-6000 nm, or in the range of 300 nm-3000 nm.

[0151] Certain embodiments of the device, apparatus and method disclosed herein are defined in the above examples. It should be understood that these examples, although indicating specific embodiments, are provided only by way of illustration. From the above discussion and these examples, those skilled in the art can determine the basic characteristics of the present disclosure, and, without departing from its spirit and scope, various changes and modifications can be made to make the compositions and methods described herein applicable to various purposes and conditions. Without departing from the essential scope of the present disclosure, various changes can be made, and equivalents can replace its elements. In addition, without departing from the essential scope of the present disclosure, many modifications can be made to adapt specific situations or materials to the teachings of the present disclosure.

Claims

1. A method for forming a perovskite precursor layer, comprising: providing a substrate stack in a deposition chamber, the substrate stack having a first charge transport layer on an electrode; depositing a first perovskite-forming composition on the substrate stack in the deposition chamber by a vapor transport deposition (VTD) process, comprising: Heating a source material to a temperature in the range of 375°C to 550°C, wherein the source material comprises at least one of: lead iodide (PbI2), lead bromide (PbBr2), cesium bromide (CsBr), cesium lead iodide (CsPbI3), cesium tin iodide (CsSnI3), lead chloride (PbCl2), tin iodide (SnI2), tin bromide (SnBr2), or tin chloride (SnCl2); providing a vapor curtain to direct vapor of the source material toward the substrate stack in the deposition chamber using a carrier gas, wherein the vapor curtain has a width greater than 1 meter, the deposition chamber pressure is in the range of 0.1-2.0 Torr, and the carrier gas flow rate is in the range of 80 sccm-150 sccm; and The precursor layer is formed to a thickness of 100-2000 nm at a deposition rate of 0.01-1.50 μm / min, wherein the precursor layer comprises a plurality of metal halide crystal grain structures, wherein: the grain structures have a height perpendicular to the surface of the substrate stack and a width parallel to the surface of the substrate stack, and an average grain width is less than one-third of an average grain height.

2. The method of claim 1, wherein: The deposition chamber has a pressure in the range of 0.1-1.0 Torr; The deposition chamber has a temperature in the range of 20°C-150°C; as well as The source material is heated to a temperature in the range of 400°C - 525°C.

3. The method of claim 1, wherein the source material is supplied as a powder prior to the heating step.

4. The method of claim 1, wherein the precursor layer comprises at least one metal halide in a crystalline matrix having a porosity in the range of 35%-65%, in the range of 40%-60%, or in the range of 45%-55%.

5. The method of claim 1, wherein the precursor layer has a thickness in the range of 200-1500 nm, in the range of 300-1200 nm, in the range of 300-900 nm, or in the range of 350-800 nm.

6. The method of claim 1, wherein the precursor layer comprises at least one of the following in a crystalline matrix having a porosity greater than 35%: lead iodide (PbI2), lead bromide (PbBr2), cesium bromide (CsBr), or cesium tin iodide (CsSnI3).

7. The method of claim 1, wherein the precursor layer comprises a plurality of lead iodide crystal grain structures, wherein: The grain structures have a height perpendicular to the surface of the matrix stack and a width parallel to the surface of the matrix stack, and at least a quarter of the grain structures of the precursor layer have a height in the range of 200 nm-700 nm and a width less than 100 nm.

8. The method of claim 1, wherein the deposition rate is in the range of 0.05-0.50 μm / min.

9. The method of claim 1, wherein the carrier gas comprises at least one of argon, helium, or nitrogen.

10. The method of claim 1, wherein the precursor layer comprises a plurality of grains, and wherein 30-100% of the grains have a size in at least one dimension having a length in the range of 200-800 nm.

11. The method of claim 1, wherein providing a stack of substrates comprises transferring the substrates to the deposition chamber via a conveyor.

12. The method of any one of claims 1-2, wherein the precursor layer thickness is in the range of 100-1900 nm, with a thickness deviation within the layer of less than 50%.

13. The method of any one of claims 1-2, wherein the porosity of the precursor layer is greater than 40%.

14. Intermediate structures for perovskite photovoltaic devices, including: a first electrode on a substrate stack, the substrate stack having a width greater than 1 meter; a first charge transport layer on the first electrode; as well as a precursor layer on the first charge transport layer, the precursor layer having a thickness in the range of 100-2000 nm, wherein the precursor layer comprises a plurality of metal halide crystal grain structures, wherein the grain structures have a height perpendicular to the surface of the substrate stack and a width parallel to the surface of the substrate stack, and an average grain width is less than one third of an average grain height; and The precursor layer comprises at least one of lead iodide (PbI2), lead bromide (PbBr2), cesium bromide (CsBr), cesium lead iodide (CsPbI3), cesium tin iodide (CsSnI3), lead chloride (PbCl2), tin iodide (SnI2), tin bromide (SnBr2), or tin chloride (SnCl2).

15. The intermediate structure of claim 14, wherein the plurality of metal halide crystalline grain structures of the precursor layer form a crystalline matrix having a porosity greater than 35%.

16. The intermediate structure of claim 14, wherein the precursor layer has a porosity in the range of 35%-65%, in the range of 40%-60%, or in the range of 45%-55%.

17. The intermediate structure of claim 14, wherein the precursor layer has a thickness in the range of 200-1500 nm, in the range of 300-1200 nm, in the range of 300-900 nm, or in the range of 350-800 nm.

18. The intermediate structure of claim 14, wherein the precursor layer has a thickness in the range of 300-1200 nanometers.

19. The intermediate structure of claim 14, wherein the thickness variation within the precursor layer is less than 30%.

20. The intermediate structure of claim 14, wherein the precursor layer comprises lead iodide.

21. The intermediate structure of claim 14, wherein the precursor layer comprises a plurality of grains, and wherein 30-100% of the grains have a size in at least one dimension having a length in the range of 200-800 nm.

22. The intermediate structure of claim 14, wherein the precursor layer comprises at least one metal halide in a crystalline matrix having a porosity greater than 35% and a thickness variation within the precursor layer less than 50%.

23. A method of forming an intermediate structure having a perovskite precursor layer for producing a photovoltaic device, comprising: providing a substrate stack in a deposition chamber, the substrate stack having a first charge transport layer on an electrode, and wherein the substrate stack has a width greater than 1 meter; depositing a first perovskite-forming composition on the substrate stack in the deposition chamber by a vapor transport deposition (VTD) process, comprising: Heating a source material to a temperature in the range of 375°C-550°C, wherein the source material is a powder comprising at least one of: lead iodide (PbI2), lead bromide (PbBr2), cesium bromide (CsBr), cesium lead iodide (CsPbI3), cesium tin iodide (CsSnI3), lead chloride (PbCl2), tin iodide (SnI2), tin bromide (SnBr2) or tin chloride (SnCl2); directing the vapor of the source material toward the substrate stack in the deposition chamber using a carrier gas, the deposition chamber having a pressure in the range of 0.1-2.0 Torr and a carrier gas flow rate in the range of 80 sccm-150 sccm; and The precursor layer is formed to a thickness of 100-2000 nm at a deposition rate of 0.01-1.50 μm / min, wherein the precursor layer comprises a plurality of metal halide crystal grain structures, wherein the grain structures have a height perpendicular to the surface of the substrate stack and a width parallel to the surface of the substrate stack, and an average grain width is less than one-third of an average grain height.

24. The method of claim 23, wherein the precursor layer has a porosity in the range of 35%-65%, in the range of 40%-60%, or in the range of 45%-55%.

25. The method of any one of claims 23-24, wherein the precursor layer has a thickness in the range of 200-1500 nm, in the range of 300-1200 nm, in the range of 300-900 nm, or in the range of 350-800 nm.

26. The method of any one of claims 23-24, wherein the precursor layer comprises a plurality of lead iodide crystal grain structures, wherein: The grain structures have a height perpendicular to the surface of the matrix stack and a width parallel to the surface of the matrix stack, and at least a quarter of the grain structures of the precursor layer have a height in the range of 200 nm-700 nm and a width less than 100 nm.

27. The method of any one of claims 23-24, wherein the deposition rate is in the range of 0.05-0.50 μm / minute.

28. The method of any one of claims 23-24, wherein the carrier gas comprises at least one of: argon, helium, or nitrogen.

29. The method of any one of claims 23-24, wherein the precursor layer comprises a plurality of grains, and wherein 30-100% of the grains have a size in at least one dimension with a length in the range of 200-800 nm.

30. The method of any one of claims 23-24, wherein the precursor layer thickness is in the range of 100-1900 nm, with a thickness variation within the layer of less than 50%.

31. The method of any one of claims 23-24, wherein the porosity of the precursor layer is greater than 40%.

32. The method of claim 23, wherein providing a stack of substrates comprises transferring the substrates to the deposition chamber via a conveyor.

33. Intermediate structures for producing perovskite photovoltaic devices, comprising: a first electrode on a substrate stack, the substrate stack having a width in the range of 1 meter to 2 meters; a first charge transport layer on the first electrode; as well as a precursor layer on the first charge transport layer, wherein: The precursor layer comprises at least one of: lead iodide (PbI2), lead bromide (PbBr2), cesium bromide (CsBr), cesium lead iodide (CsPbI3), cesium tin iodide (CsSnI3), lead chloride (PbCl2), tin iodide (SnI2), tin bromide (SnBr2) or tin chloride (SnCl2); the thickness of the precursor layer is in the range of 100-2000nm; and The precursor layer comprises a plurality of metal halide crystal grain structures, wherein the grain structures have a height perpendicular to the surface of the substrate stack and a width parallel to the surface of the substrate stack, and an average grain width is less than one third of an average grain height.

34. The intermediate structure of claim 33, wherein the plurality of metal halide crystalline grain structures of the precursor layer form a crystalline matrix having a porosity greater than 35%.

35. The intermediate structure of claim 33, wherein the precursor layer has a porosity in the range of 35%-65%, in the range of 40%-60%, or in the range of 45%-55%.

36. The intermediate structure of any one of claims 33-35, wherein the precursor layer has a thickness in the range of 200-1500 nm, in the range of 300-1200 nm, in the range of 300-900 nm, or in the range of 350-800 nm.

37. The intermediate structure of any one of claims 33-35, wherein the precursor layer has a thickness in the range of 300-1200 nanometers.

38. The intermediate structure of any one of claims 33-35, wherein the thickness variation within the precursor layer is less than 30%.

39. The intermediate structure of any one of claims 33-35, wherein the precursor layer is composed of lead iodide (PbI2), lead bromide (PbBr2), cesium bromide (CsBr), cesium tin iodide (CsSnI3), or a combination thereof.

40. The intermediate structure of any one of claims 33-35, wherein the precursor layer comprises lead iodide (PbI2).

41. The intermediate structure of any one of claims 33-35, wherein the precursor layer comprises a plurality of grains, and wherein 30-100% of the grains have a size in at least one dimension having a length in the range of 200-800 nm.

42. An intermediate structure for producing a perovskite photovoltaic device, formed by the method of any one of claims 1-13 or 23-32.

43. A method of manufacturing a perovskite absorber layer for a photovoltaic device, comprising: Providing an intermediate structure as described in any one of claims 14-22 or 33-42; exposing the intermediate structure to a second perovskite-forming composition; as well as The intermediate structure having the second perovskite-forming composition is annealed.

44. The method of claim 43, wherein: The second perovskite-forming composition includes at least one of a cesium (Cs) cation, a rubidium (Rb) cation, a methylammonium (MA) compound, or a formamidine (FA) compound.

45. The method of claim 43 or 44, wherein The annealing step is performed at a pressure ranging from 0.1 Torr to 1000 Torr, a duration ranging from 10 minutes to 90 minutes, a humidity ranging from 45% to 60%, and a temperature ranging from 50°C to 150°C.

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