Construction of solar modules to extend lifecycles of perovskite solar cells contained therein

Abstract

Perovskite solar cells and solar modules containing the same are described. Methods of manufacturing such solar cells and modules for extending lifecycles of the perovskite solar cells are also described. In one example, a perovskite solar cell is provided. The perovskite solar cell includes: a first transparent conductive oxide layer; a hole transport layer disposed on the first transparent conductive oxide layer; a perovskite layer disposed on the hole transport layer; an electron transport layer disposed on the perovskite layer; a second transparent conductive oxide layer disposed on the electron transport layer; and an electrically insulating layer disposed on the second transparent conductive oxide layer. In another example, a solar module is provided. The solar module includes: a substrate; a superstrate; an edge seal disposed between the substrate and the superstrate; a perovskite photovoltaic disposed on the substrate; and an oxygen-barrier tape adhered to the substrate, superstate, and edge seal.

Description

Attorney Docket No.54741-0044WO1 CONSTRUCTION OF SOLAR MODULES TO EXTEND LIFECYCLES OF PEROVSKITE SOLAR CELLS CONTAINED THEREIN FIELD OF THE INVENTION

[0001] The invention is in the field of solar cells, in particular, perovskite solar cells and solar modules containing the same. BACKGROUND

[0002] Solar cells, also referred to as photovoltaic cells, are optoelectronic devices that convert light into electricity using the photovoltaic effect.

[0003] Silicon solar cells are capable of converting light within a wavelength range of about 300 nanometers (“nm”) to 1100 nm into electricity. However, the conversion efficiency of silicon solar cells decreases appreciably as the wavelength of light decreases from 1100 nm. Additionally, silicon solar cells are unable to convert wavelengths of light above about 1100 nm to electricity because such photons lack the energy required to overcome the bandgap of silicon.

[0004] Perovskite solar cells are solar cells that include a photoactive layer composed of a perovskite. Such perovskite layers can be formed by applying a perovskite precursor to a substrate. The perovskite precursor can then be annealed to form the photoactive perovskite layer.

[0005] Perovskite layers often include metal halides, which are known to have at least three degradation mechanisms: (1) water-assisted oxidation; (2) oxidation in the presence of light and oxygen, which may or may not result in water being generated as a product of reaction, as described by Siegler, Timothy D., et al. “Water-accelerated photooxidation of CH3NH3PbI3 perovskite,” Journal of the American Chemical Society 144.12 (2022): 5552- 5561; and (3) diffusion of halides (such as methylammonium halides) out of the perovskite material as described by Boyd, Caleb C., et al. “Barrier design to prevent metal-induced degradation and improve thermal stability in perovskite solar cells,” ACS Energy Letters 3.7 (2018): 1772-1778.

[0006] A tandem solar cell has two individual solar cells stacked on top of one another, where a top cell absorbs incident light, and a bottom cell absorbs residual light transmitted through the top cell. The bottom cell can be a silicon solar cell, and the top cell can be a different type of solar cell, such as a perovskite solar cell. The top cell can have a higher bandgap than the silicon solar cell. Accordingly, the top cell can be capable of efficientlyAttorney Docket No.54741-0044WO1 converting shorter wavelengths of light to electricity. The top cell can be transparent to longer wavelengths of light, which can allow the underlying silicon solar cell to absorb and convert such longer wavelengths of light to electricity. Thus, the tandem solar cell can generate electricity over a wider wavelength range of light and with a higher conversion efficiency than either cell individually.

[0007] A solar module, also referred to as a solar panel, includes multiple solar cells electrically connected to one another in series, parallel, or series-parallel. A tandem solar module includes multiple tandem solar cells electrically connected to one another. A solar module can also include other components, such as a frame, a junction box, etc. SUMMARY

[0008] In general, the present disclosure describes construction and encapsulation of solar modules, e.g., tandem solar modules, to extend lifecycles of perovskite solar cells contained therein. The perovskite solar cells described herein can be used in single junction solar modules and tandem solar modules, such as tandem silicon-perovskite solar modules.

[0009] A tandem solar module is a solar module composed of an array of tandem solar cells arranged between a top glass sheet and a back sheet.

[0010] A tandem silicon-perovskite solar cell includes a silicon solar cell and a perovskite solar cell, with the perovskite solar cell usually stacked on top of the silicon solar cell. That is, when installed, sunlight is first incident on the perovskite solar cell. The perovskite solar cell generally has a higher bandgap than the silicon solar cell. For example, the perovskite solar cell can have a bandgap of about 1.7 electron volts (“eV”) while the silicon solar cell has a bandgap of about 1.1 eV. Accordingly, the perovskite solar cell is capable of efficiently converting shorter wavelengths of light to electricity. The perovskite solar cell can be transparent to longer wavelengths of light, which allows the underlying silicon solar cell to absorb and convert such longer wavelengths of light to electricity. Together, the perovskite solar cell and the silicon solar cell are capable of efficiently converting a wider spectrum of light to electricity than a single solar cell, e.g., there may be less thermalization loss in a tandem solar cell than in a single solar cell resulting in a higher full spectrum efficiency. The addition of perovskite solar cells can improve the resultant solar modules by decreasing cost, improving performance per weight of the module, improving overall performance of the module, and the like.Attorney Docket No.54741-0044WO1

[0011] The silicon solar cell can be a monocrystalline or multi-crystalline silicon solar cell. The silicon solar cell can be a component of a conventional silicon solar panel that includes multiple such silicon solar cells, e.g., a 32-cell, 36-cell, 48-cell, 60-cell, 72-cell, 96- cell, or 144-cell silicon solar panel. The solar panel can also have a back sheet on which the silicon solar cell is disposed. Encapsulant can cover the top and bottom of the silicon solar cell to prevent it from being exposed to dust and moisture.

[0012] The perovskite solar cell can be deposited on a bottom surface of a top glass sheet of the silicon solar panel. This differs from the construction of conventional tandem solar modules in which a perovskite solar cell is disposed directly on top of a silicon wafer. Depositing the perovskite solar cell on the bottom surface of the top glass sheet allows manufacturers to incorporate perovskite solar cells into their conventional silicon solar panels with little or no re-tooling or process changes. Instead, manufacturers can merely substitute a conventional glass sheet with the perovskite glass sheet. This disclosure may refer to the perovskite glass sheet, or perovskite-on-glass, as “active glass”.

[0013] The perovskite solar cell includes a first transparent conductive oxide (“TCO”) layer which can be deposited directly on the top glass sheet, a hole transport layer (“HTL”) deposited on the first TCO layer, a perovskite layer deposited on the HTL, an electron transport layer (“ETL”) deposited on the perovskite layer, and a second TCO layer deposited on the ETL. The first and second TCO layers can serve as terminals for the perovskite solar cell. The ETL and HTL facilitate electron and hole transport, respectively, while inhibiting hole and electron transport, respectively. The perovskite layer is the photoactive layer of the perovskite solar cell. In other words, the perovskite layer can absorb light to generate charge carriers, which results in a voltage and current flow across the terminals of the perovskite solar cell. In some examples, the perovskite solar cell further includes an electrically insulating layer (“EIL”) deposited on the second TCO layer. The EIL can serve as a high- quality vapor diffusion barrier to prevent diffusion of volatile species out of the perovskite layer, as well as diffusion of gas species or water vapor into the perovskite layer. Ingress and egress of reactive species into and out of the perovskite layer, e.g., organic cations, lead halides, halide gas, water vapor, and oxygen, can stem from lithography or laser-scribed features that expose the perovskite layer to the environment. The EIL provides passivation of such lithography or laser-scribed features while buttressing the vapor barrier properties of the second TCO layer. The EIL is preferably deposited using a low-temperature process to mitigate deterioration of the underlying perovskite layer.Attorney Docket No.54741-0044WO1

[0014] The perovskite solar cell and the silicon solar cell can be electrically isolated from each other, and each cell can have its own terminals. That is, the tandem solar cell can be a four-terminal cell, having two respective terminals for each of the perovskite and silicon solar cells. The perovskite solar cell and the silicon solar cell can be connected in series or parallel by connecting the terminals in the appropriate manner. In the case of a series connection, the perovskite solar cell and the silicon solar cell can be current-matched. In the case of a parallel connection, the perovskite solar cell and the silicon solar cell can be voltage-matched.

[0015] In some examples, the solar modules described herein are encapsulated with an edge seal and an oxygen-barrier tape (e.g., a metallized tape) to prevent ingress of water and oxygen vapor into the solar module. Suitable oxygen-barrier tapes typically include layers of metal such as aluminum, or recently oxygen-barrier polymers such as ethylene-vinyl alcohol (EVOH). EVOH can have oxygen-vapor transmission rates as low as 2.5 grams of vapor per day per square meter (g / m2 / day). However, metallized tapes can have vapor transmission as low as 0.2 g / m2 / day. In combination with the edge seal, the metallized tape can significantly reduce the effective cross-sectional area and increase the effective length through which water and oxygen vapor diffuses into the solar module. The solar module can further include an oxygen gettering system arranged within an interior of the solar module lamination, e.g., formed on a bottom surface of a top glass sheet of a silicon solar panel, directly on a perovskite photovoltaic, or both. The oxygen gettering system can be configured to capture any residual oxygen vapor that manages to diffuse into the solar module through the edge seal and metallized tape. Various examples of oxygen gettering systems are described herein that incorporate a sacrificial material composed or doped with an oxygen getter for capturing oxygen. In the particular case of using a perovskite as the oxygen getter, there may be mechanisms of reaction between some metal halide perovskites that produce water as a byproduct. In such a case, the solar modules described herein provide a secondary water vapor barrier and / or absorber material situated between the sacrificial perovskite and the perovskite photovoltaic devices.

[0016] These features and other features relating to the perovskite solar cells, the solar modules containing such perovskite solar cells, and the methods of fabricating such solar cells and solar modules are summarized below.

[0017] In one aspect, a perovskite solar cell is provided. The perovskite solar cell includes: a first transparent conductive oxide layer; a hole transport layer disposed on the first transparent conductive oxide layer; a photoactive, perovskite layer disposed on the hole transport layer; an electron transport layer disposed on the perovskite layer; a secondAttorney Docket No.54741-0044WO1 transparent conductive oxide layer disposed on the electron transport layer; an electrically insulating layer disposed on the second transparent conductive oxide layer; and one or more sets of P1, P2, and P3 scribe lines segmenting the perovskite solar cell into a number of perovskite subcells, where each set of P1, P2, and P3 scribe lines includes: a P1 scribe line extending through each of the hole transport and first transparent conductive oxide layers, the perovskite layer filling the P1 scribe line; a P2 scribe line extending through each of the electron transport, perovskite, and hole transport layers, the second transparent conductive oxide layer filling the P2 scribe line; and a P3 scribe line extending through each of the second transparent conductive oxide, electron transport, perovskite, and hole transport layers, the electrically insulating layer filling the P3 scribe line.

[0018] In some implementations of the perovskite solar cell, the perovskite layer has a thickness of 1,000 nanometers (nm) or less.

[0019] In some implementations of the perovskite solar cell, the perovskite layer has thickness in a range from 400 nm to 600 nm.

[0020] In some implementations of the perovskite solar cell, the perovskite layer is composed of a perovskite selected from the group represented by MAn1FAn2Csn3PbX3, MA is methylammonium, FA is formamidinium, Cs is Cesium, Pb is lead, and X is a halogen, and n1, n2, and n3 are each independently greater than 0 and less than 1.

[0021] In some implementations of the perovskite solar cell, n1 + n2 + n3 = 1.

[0022] In some implementations of the perovskite solar cell, the perovskite layer is composed of methylammonium lead trihalide (CH3NH3PbX3) or a formamidinium lead trihalide (H2NCHNH2PbX3), and X is a halogen.

[0023] In some implementations of the perovskite solar cell, the halogen is selected from the group consisting of: fluorine, chlorine, bromine, and iodine.

[0024] In some implementations of the perovskite solar cell, the halogen is iodine.

[0025] In some implementations of the perovskite solar cell, the hole transport layer is composed of one or more nickel oxides.

[0026] In some implementations of the perovskite solar cell, the electron transport layer is composed of phenyl-C61-butyric acid methyl ester or buckminsterfullerene.

[0027] In some implementations of the perovskite solar cell, the first and second transparent conductive oxide layers are each composed of indium tin oxide.

[0028] In some implementations of the perovskite solar cell, the perovskite layer is doped with one or more of: bromine, cesium iodide, or methylammonium chloride.Attorney Docket No.54741-0044WO1

[0029] In some implementations of the perovskite solar cell, the electrically insulating layer has thickness of 500 nm or less.

[0030] In some implementations of the perovskite solar cell, the electrically insulating layer has a thickness of 100 nm or less.

[0031] In some implementations of the perovskite solar cell, the electrically insulating layer is composed of silicon dioxide, titanium dioxide, silicon nitride, aluminum oxide, parylene, or a photopolymer.

[0032] In a second aspect, a solar module is provided. The solar module includes: a substrate having: (i) a first surface, and (ii) a second, opposite surface; a superstrate arranged parallel to the substrate, the superstrate having: (i) a first surface facing the first surface of the substrate, and (ii) a second, opposite surface; an edge seal disposed between the first surfaces of the substrate and superstrate, where each of the substrate, superstrate, and edge seal has a respective lateral surface aligned with one another; a perovskite photovoltaic disposed on the first surface of the substrate, the edge seal arranged laterally about the perovskite photovoltaic; and an oxygen-barrier tape adhered to the lateral surfaces of the substrate, superstate, and edge seal, the oxygen-barrier tape extending onto the second surfaces of the substrate and superstrate.

[0033] In some implementations of the solar module, the edge seal has a width of 5 millimeters (mm) or more, and the oxygen-barrier tape extends 5 mm or more onto the second surfaces of the substrate and superstrate.

[0034] In some implementations of the solar module, the oxygen-barrier tape includes: a metal layer and an adhesive layer; or an ethylene-vinyl alcohol layer and the adhesive layer.

[0035] In some implementations of the solar module, the metal layer is composed of aluminum, gold, silver, copper, nickel, chromium, steel, or zinc.

[0036] In some implementations of the solar module, the adhesive layer is composed of an acrylic adhesive.

[0037] In some implementations of the solar module, the adhesive layer is loaded with a desiccant, an oxygen getter, or both.

[0038] In some implementations of the solar module, the oxygen-barrier tape further includes a polymer layer disposed between the metal and adhesive layers.

[0039] In some implementations of the solar module, the polymer layer is composed of polyisobutylene, polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyethersulfone, polyethylene naphthalate, or polyimide.Attorney Docket No.54741-0044WO1

[0040] In some implementations of the solar module, the polymer layer is loaded with a desiccant, an oxygen getter, or both.

[0041] In some implementations of the solar module, the edge seal is composed of polyisobutylene.

[0042] In some implementations of the solar module, the edge seal is loaded with a desiccant, an oxygen getter, or both.

[0043] In some implementations, the solar module further includes a sacrificial material including an oxygen getter disposed on the first surface of the substrate, the sacrificial material arranged laterally about the perovskite photovoltaic.

[0044] In some implementations, the solar module further includes a confinement well disposed on the first surface of the substrate, the confinement well including: a first portion arranged laterally about the perovskite photovoltaic; and a second portion arranged laterally about the first portion, where the sacrificial material is positioned between the first and second portions of the confinement well.

[0045] In some implementations of the solar module, the confinement well is composed of a polymer.

[0046] In some implementations, the solar module further includes an absorber material including a desiccant disposed on the first surface of the substrate, the absorber material arranged laterally about the perovskite photovoltaic.

[0047] In some implementations of the solar module, the oxygen getter generates water when combining with oxygen, and the absorber material is positioned between the sacrificial material and the perovskite photovoltaic.

[0048] In some implementations of the solar module, the sacrificial material is in contact with the edge seal and the absorber material.

[0049] In some implementations of the solar module, the sacrificial and absorber materials are further disposed on the first surface of the superstrate.

[0050] In some implementations, the solar module further includes: a layer of an absorber material disposed on the perovskite photovoltaic, the absorber material including a desiccant; and a layer of a sacrificial material disposed on the layer of the absorber material, the sacrificial material including an oxygen getter that generates water when combining with oxygen.

[0051] In some implementations of the solar module, the layer of the absorber material is further disposed on the first surface of the substrate.Attorney Docket No.54741-0044WO1

[0052] In some implementations of the solar module, the layers of the sacrificial and absorber materials are in contact with the edge seal.

[0053] In some implementations of the solar module, the sacrificial material is composed of the oxygen getter.

[0054] In some implementations of the solar module, the sacrificial material is a porous monolith of the oxygen getter.

[0055] In some implementations of the solar module, the sacrificial material is loaded with the oxygen getter.

[0056] In some implementations of the solar module, the sacrificial material is composed of a polymer having the oxygen getter suspended therein.

[0057] In some implementations of the solar module, the sacrificial material is composed of a gel or liquid solution having the oxygen getter suspended therein.

[0058] In some implementations of the solar module, the oxygen getter is in a powdered form having a nominal particle size of 20 micrometers or less.

[0059] In some implementations of the solar module, the oxygen getter is selected from the group consisting of: quantum dots, iron, zirconium, titanium, copper, aluminum, magnesium, barium, sodium sulfite, hydrazine, zeolite, catechol, hydroquinone, ascorbic acid, or activated carbon.

[0060] In some implementations of the solar module, the oxygen getter is a perovskite selected from the group represented by MAn1FAn2Csn3PbX3,

[0061] MA is methylammonium, FA is formamidinium, Cs is Cesium, Pb is lead, and X is a halogen, and n1, n2, and n3 are each independently greater than 0 and less than 1.

[0062] In some implementations of the solar module, the perovskite photovoltaic includes one or more perovskite solar cells.

[0063] In some implementations of the solar module, each perovskite solar cell is configured according to the perovskite solar cell of the first aspect in any of its abovementioned implementations.

[0064] In some implementations, the solar module is a tandem solar module including: a first encapsulant disposed on the perovskite photovoltaic; a silicon photovoltaic disposed on the first encapsulant; and a second encapsulant disposed between the silicon photovoltaic and the first surface of the superstrate, where the edge seal is arranged laterally about the perovskite photovoltaic, silicon photovoltaic, and first and second encapsulants.

[0065] In some implementations of the solar module, the substrate is glass, and the superstate is glass or a back sheet.Attorney Docket No.54741-0044WO1

[0066] In some implementations of the solar module, the first encapsulant is loaded with a desiccant, an oxygen getter, or both.

[0067] In some implementations, the solar module has a T80 time of 12 years or more.

[0068] In a third aspect, a method is provided. The method includes: providing a substrate supporting a first transparent conductive oxide layer and a hole transport layer disposed on the first transparent conductive oxide layer; applying a perovskite precursor to the hole transport layer; annealing the perovskite precursor to form a photoactive, perovskite layer on the hole transport layer; applying an electron transport layer to the perovskite layer; applying a second transparent conductive oxide layer to the electron transport layer; and applying an electrically insulating layer to the second transparent conductive oxide layer to form a perovskite photovoltaic; and laser scribing the perovskite photovoltaic to generate a number of perovskite solar cells.

[0069] In some implementations of the method, the perovskite precursor includes a metal halide and organohalides selected from the group consisting of: formamidinium chloride, formamidinium bromide, formamidinium iodide, methylammonium chloride, methylammonium bromide, methylammonium iodide, and butylammonium halides.

[0070] In some implementations of the method, the perovskite precursor includes one or more additives selected from the group consisting of: bromine, cesium iodide, and methylammonium chloride.

[0071] In some implementations of the method, providing the substrate supporting the transparent conductive oxide layer and the hole transport layer disposed on the transparent conductive oxide layer includes: providing the substrate; applying the transparent conductive oxide layer to the substrate; and applying the hole transport layer to the transparent conductive oxide layer.

[0072] In some implementations of the method, each perovskite solar cell is segmented into a number of perovskite subcells by sets of P1, P2, and P3 scribe lines, and each set of P1, P2, and P3 scribe lines includes: a P1 scribe line extending through each of the hole transport and first transparent conductive oxide layers, the perovskite layer filling the P1 scribe line; a P2 scribe line extending through each of the electron transport, perovskite, and hole transport layers, the second transparent conductive oxide layer filling the P2 scribe line; and a P3 scribe line extending through each of the second transparent conductive oxide, electron transport, perovskite, and hole transport layers, the electrically insulating layer filling the P3 scribe line.Attorney Docket No.54741-0044WO1

[0073] In some implementations, the method further includes: prior to applying the perovskite precursor to the hole transport layer, laser scribing the hole transport layer to generate the P1 scribe line of each set of P1, P2, and P3 scribe lines; prior to applying the electron transport layer to the perovskite layer, laser scribing the electron transport layer to generate the P2 scribe line of each set of P1, P2, and P3 scribe lines; and prior to applying the electrically insulating layer to the second transparent conductive oxide layer, laser scribing the second transparent conductive oxide layer to generate the P3 scribe line of each set of P1, P2, and P3 scribe lines.

[0074] In some implementations, the method further includes forming an oxygen gettering system on the substrate, perovskite photovoltaic, or both.

[0075] In some implementations of the method, forming the oxygen gettering system on the substrate, perovskite photovoltaic, or both includes: depositing a sacrificial material including an oxygen getter on the substrate and laterally about the perovskite photovoltaic.

[0076] In some implementations of the method, the oxygen getter generates water when combining with oxygen, and forming the oxygen gettering system on the substrate, perovskite photovoltaic, or both further includes depositing an absorber material including a desiccant on the substrate and laterally about the perovskite photovoltaic.

[0077] In some implementations of the method, forming the oxygen gettering system on the substrate, perovskite photovoltaic, or both includes: forming a confinement well on the substrate, including: deposing a first portion of the confinement well on the substrate and laterally about the perovskite photovoltaic; and depositing a second portion of the confinement well on the substrate and laterally about the first portion; and depositing a sacrificial material including an oxygen getter between the first and second portions of the confinement well.

[0078] In some implementations of the method, forming the oxygen gettering system on the substrate, perovskite photovoltaic, or both includes: depositing a layer of an absorber material on the perovskite photovoltaic, the sacrificial material including a desiccant; and depositing a layer of a sacrificial material on the layer of the absorber material, the sacrificial material including an oxygen getter that generates water when combining with oxygen.

[0079] In some implementations of the method, the substrate is a top glass sheet of a silicon solar panel, and the method further includes: providing the silicon solar panel; connecting the perovskite solar cells to a number of silicon solar cells of the silicon solar panel to form a tandem solar module; encapsulating the tandem solar module; and adhering an oxygen-barrier tape to an edge of the tandem solar module.Attorney Docket No.54741-0044WO1

[0080] In some implementations of the method, encapsulating the tandem solar module includes: applying an encapsulant to the perovskite solar cells; and applying an edge seal to the tandem solar module.

[0081] In some implementations of the method, adhering the oxygen-barrier tape to the edge of the tandem solar module includes: adhering the oxygen-barrier tape to a lateral surface of tandem solar module; and adhering the oxygen-barrier tape to a top and bottom surface of the tandem solar module.

[0082] Particular embodiments of the subject matter described in this specification can be implemented so as to realize one or more of the following advantages.

[0083] Water-assisted and dry oxidation are two well-known degradation mechanisms of perovskite solar cells. In many solar module laminates, an encapsulant is used to adhere layers together conformally, passivate exposed surfaces of solar cell components, and provide electrical isolation for such solar cell components. Encapsulants reduce the rate of water and oxygen diffusion, but not sufficiently well to eliminate these degradation mechanisms entirely. Even for solar modules with glass-glass laminations, diffusion from the edges of the solar module, if protected only by typical sheet encapsulant materials, allows sufficient water and oxygen vapor ingress from the edges of glass / glass laminates to markedly reduce the lifecycles of the perovskite solar cells contained therein. In the case of water vapor diffusion, polyisobutylene-based edge seals have been developed, loaded with desiccant water absorber. These have proven commercially viable for use in cadmium telluride solar panels for nearly two decades. The advantages of soft materials such as desiccant-loaded polyisobutylene, as compared to hermetic seals, e.g., sintered glass or metal frits, are manifold. They are not brittle and therefore are tolerant to shock and vibration, they are inexpensive, and they can be laminated into a glass / glass laminate “sandwich” at the same temperatures as sheet encapsulant. Hard hermetic seals, on the other hand, are sealed by locally high temperatures which may break the glass or damage nearby perovskite material which cannot tolerate temperatures above about 140oC for any substantial amount of time.

[0084] However, with respect to the problem of oxygen diffusion into the laminate, the hard hermetic seals described above would appear to be the only viable possible solution, prior to the present disclosure. As a result, current solar module constructions without hermetic seals can have T80 times of only about three years or less, which hinders their commercial viability, longevity as renewable energy sources, and output energy yield. Current techniques for constructing and encapsulating solar modules have primarily focused on reducing water vapor ingress into the solar module. Perovskite solar cells, however, areAttorney Docket No.54741-0044WO1 highly sensitive to oxygen. Currently available edge seals and encapsulations do not provide a sufficient vapor barrier to such reactive species. Hence, oxygen ingress can be the limiting factor for perovskite solar cell lifecycles in state-of-the-art solar modules.

[0085] Moreover, it is well-known that perovskite materials have relatively high volatility, low boiling point, and high vapor pressure (even at temperatures of less than 80 degrees Celsius). Solar modules can reach such temperatures in terrestrial (e.g., rooftop) applications which can cause generation and diffusion of volatile species out of the perovskite materials, leading to further degradation and reduced lifecycles. For example, lithography features inscribed into a perovskite solar cell can facilitate egress of volatile species out of a perovskite layer (and ingress of water and oxygen vapor into the perovskite layer) if not sufficiently passivated. This can occur even in the presence of prototypical solar module encapsulants. While encapsulants provide some passivation, they generally do not provide a sufficient barrier for vapor diffusion.

[0086] To overcome some, or all, of these aforementioned challenges, this specification describes improved techniques for constructing and encapsulating solar modules, e.g., tandem solar modules, to extend lifecycles of perovskite solar cells contained therein.

[0087] In one approach, the solar modules described herein are encapsulated with an edge seal and an oxygen-barrier tape (e.g., a metallized tape) to prevent water and oxygen vapor ingress, which constitute the dominate degradation mechanisms of a perovskite solar cell. Additionally, the perovskite solar cell can include an electrically insulating layer deposited on a transparent conductive oxide layer (e.g., serving as a terminal of the perovskite solar cell). The electrically insulating layer can passivate the surfaces of a perovskite layer exposed from lithography operations, e.g., laser scribing of P1, P2, and P3 scribe lines, as well as buttress vapor barrier properties of the transparent conductive oxide layer. In addition to the transparent conductive oxide layer, the electrically insulating layer serves as a high-quality vapor diffusion barrier, preventing ingress of water and oxygen vapor into the perovskite layer and egress of volatiles species out of the perovskite layer. The solar modules can further include an oxygen gettering (e.g., oxygen reacting) system arranged within the interior lamination of the solar module to capture any residual oxygen vapor that manages to diffuse through the edge of the solar module. In the case that said oxygen-reacting system reacts with oxygen to form water, a second water vapor-barrier layer may be interposed between the oxygen-reacting system and the device perovskite material. The combination of the edge seal and oxygen-barrier tape for preventing water and oxygen vapor ingress, the electrically insulating layer for passivating lithography or laser-scribed features, and an oxygen getteringAttorney Docket No.54741-0044WO1 system for residual oxygen capture (optionally configured with a secondary water vapor barrier if the oxygen getter generates water) can increase the T80 time of a perovskite solar module to about 12 years or more. This is about a four-times improvement over some state- of-the-art perovskite solar module constructions. Moreover, these techniques can be implemented by solar panel manufacturers with little re-tooling or process changes, while being highly economical and easily scalable.

[0088] Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, where only illustrative embodiments of the present disclosure are shown and described. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. BRIEF DESCRIPTION OF THE DRAWINGS

[0089] FIG.1A schematically illustrates an example of a tandem silicon-perovskite solar cell.

[0090] FIG.1B schematically illustrates an example of a perovskite solar cell.

[0091] FIGs.2A-2B schematically illustrate an example of a perovskite solar cell segmented into multiple perovskite subcells by P1, P2, P3, and P4 scribe lines.

[0092] FIGs.3A-3C schematically illustrate an example of a tandem silicon-perovskite solar module encapsulated with an edge seal and a metallized tape.

[0093] FIGs.4A-4D schematically illustrate additional examples of tandem solar modules encapsulated with an edge seal, a metallized tape, and an oxygen gettering system.

[0094] FIG.5 is a flowchart of an example fabrication process for forming a perovskite photovoltaic on a substrate.

[0095] FIG.6A-6D are flowcharts of example fabrication processes for forming different types of oxygen gettering systems on a perovskite photovoltaic.

[0096] FIG.7 is a flowchart of an example fabrication process for forming a tandem solar module. DETAILED DESCRIPTION

[0097] FIG.1A schematically illustrates an example of a tandem silicon-perovskite solar cell 100. The tandem solar cell 100 includes a top glass sheet 105, a perovskite solar cell 240,Attorney Docket No.54741-0044WO1 a first encapsulant 135-1, a silicon solar cell 140, a second encapsulant 135-2, and a back sheet 145 stacked on top of one another. Depending on the context, the top glass sheet 105 may be referred to herein as a substrate (or a superstrate), and the back sheet 145 may be referred to herein as a superstrate (or a substrate). The combination of a substrate and superstrate provides the lamination construction of a solar module in which multiple solar cells, e.g., tandem solar cells 100, are encapsulated. Details relating to improved techniques for constructing and encapsulating solar modules to extend lifecycles of perovskite solar cells contained therein are described with reference to FIGs.3A-4D.

[0098] The tandem solar cell 100 can be part of a tandem solar module 10, e.g., a tandem solar cell in an array of tandem solar cells contained in the tandem solar module 10, that has a form factor corresponding to a conventional silicon solar panel. For example, the top glass sheet 105 can have a form factor that corresponds to a 32-cell, 36-cell, 48-cell, 60-cell, 72- cell, 96-cell, or 144-cell silicon solar panel. The top glass sheet 105 can have a thickness of at least about 2.0 millimeters (mm), 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, or more. The top glass sheet 105 can have a thickness of at most about 5.0 mm, 4.5 mm, 4.0 mm, 3.5 mm, 3.0 mm, 2.5 mm, 2.0 mm, or less. The top glass sheet 105 protects the underlying layers of the tandem solar cell 100 from dust and moisture. The top glass sheet 105 is transparent to allow light to penetrate the underlying perovskite 240 and silicon 140 solar cells. The top glass sheet 105 has a top surface 106T and a bottom surface 106B. In some cases, the top surface 106T of the top glass sheet 105 is covered with magnesium fluoride (MgF2) and / or polydimethylsiloxane (PDMS), e.g., 1:10 alumina PDMS, textured 1:50 alumina PDMS, or textured PDMS, which generally improves light trapping and refractive index matching. In some examples, the top surface 106T of the top glass sheet 105 is covered with an antireflective coating to reduce reflections of light within a particular spectral range. Alternatively, or in addition, the bottom surface 106B of the top glass sheet 105 can be textured in order to enable more light scattering back into the tandem solar cell 100.

[0099] FIG.1B schematically illustrates the perovskite solar cell 240 of the tandem solar cell 100 depicted in FIG.1A. The perovskite solar cell 240 includes a first transparent conducting oxide (TCO) layer 110, a hole transport layer (HTL) 115, a perovskite layer 120, an electron transport layer (ETL) 125, a second TCO layer 130, and an electrically insulating layer (EIL) 150 stacked on top of one another. The perovskite solar cell 240 can be fabricated on the bottom surface 105B of the top glass sheet 105 through methods described with reference to FIG.7. Further details relating to such manufacturing methods are described inAttorney Docket No.54741-0044WO1 Int’l. Appl. No. PCT / US2021 / 051465, filed September 22, 2021, and titled “Methods and Devices for Integrated Tandem Solar Module Fabrication,” which is incorporated herein by reference in its entirety for all purposes.

[0100] The perovskite solar cell 240 generally has a higher bandgap than the silicon solar cell 140. For example, the perovskite solar cell 240 can have a bandgap of about 1.30 electron volts (“eV”) to 2.10 eV, or greater. The perovskite solar cell 240 can have a bandgap of about 1.30, 1.31, 1.32, 1.33, 1.34, 1.35, 1.36, 1.37, 1.38, 1.39, 1.40, 1.41, 1.42, 1.43, 1.44, 1.45, 1.46, 1.47, 1.48, 1.49, 1.50, 1.51, 1.52, 1.53, 1.54, 1.55, 1.56, 1.57, 1.58, 1.59, 1.60, 1.61, 1.62, 1.63, 1.64, 1.65, 1.66, 1.67, 1.68, 1.69, 1.70, 1.71, 1.72, 1.73, 1.74, 1.75, 1.76, 1.77, 1.78, 1.79, 1.80, 1.81, 1.82, 1.83, 1.84, 1.85, 1.86, 1.87, 1.88, 1.89, 1.90, 1.91, 1.92, 1.93, 1.94, 1.95, 1.96, 1.97, 1.98, 1.99, 2.00, 2.01, 2.02, 2.03, 2.04, 2.05, 2.06, 2.07, 2.08, 2.09, 2.10, or greater eV. In contrast, the silicon solar cell 140 can have a bandgap of about 1.1 eV. Accordingly, the perovskite solar cell 240 is capable of efficiently converting shorter wavelengths of light to electricity compared to the silicon solar cell 140. The perovskite solar cell 240 can be transparent to longer wavelengths of light, which allows the underlying silicon solar cell 140 to absorb and convert such longer wavelengths of light to electricity. Together, the perovskite solar cell 240 and the silicon solar cell 140 can be capable of efficiently converting a wider spectrum of light to electricity than a single solar cell. The perovskite solar cell 240 can have a thickness of at least about 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 micrometer, 1.5 micrometers, 2 micrometers, 2.5 micrometers, 5 micrometers, or more. The perovskite solar cell 240 can have a thickness of at most about 5 micrometers, 2.5 micrometers, 2 micrometers, 1.5 micrometers, 1 micrometer, 900 nm, 800 nm, 700 nm, 600 nm, 500 nm, or less.

[0101] The first TCO layer 110 is disposed directly on the bottom surface 106B of the top glass sheet 105. Depositing the first TCO layer 110 directly on the top glass sheet 105 can prevent damage to the HTL 115 and the perovskite layer 120. The first TCO layer 110 can serve as the positive terminal or cathode of the perovskite solar cell 240. In some examples, the first TCO layer 110 is composed of indium tin oxide (ITO) or doped ITO. The first TCO layer 110 can have a thickness of at least about 100 nanometers (nm), 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 micrometer, or more. The first TCO layer 110 can have a thickness of at most about 1 micrometer, 900 nm, 800 nm, 700 nm, 600 nm, 500 nm, 400 nm, 300 nm, 200 nm, 100 nm, or less. The first TCO layer 110 can have a resistance of at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, or more Ohm / square meter. The first TCO layer 110 can have a resistance ofAttorney Docket No.54741-0044WO1 at most about 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, or less Ohm / square meter.

[0102] The HTL 115 is disposed on the first TCO layer 110. The HTL 115 facilitates the transport of holes from the perovskite layer 120 to the first TCO layer 110 without compromising transparency and conductivity. In contrast, the HTL 115 inhibits electron transport. In some examples, the HTL 115 is composed of one or more nickel oxides. In other examples, the HTL 115 is composed of another appropriate p-type material described at the end of this disclosure. The HTL 115 can have a thickness of at least about 5 nm, l0 nm, 20 nm, 50 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 micrometer, or more. The HTL 115 can have a thickness of at most about 1 micrometer, 900 nm, 800 nm, 700 nm, 600 nm, 500 nm, 400 nm, 300 nm, 200 nm, 100 nm, 50 nm, 20 nm, 10 nm, 5 nm, or less.

[0103] The perovskite layer 120 is disposed on the HTL 115. The perovskite layer 120 is the photoactive layer of the perovskite solar cell 240. That is, the perovskite layer 120 absorbs light and, in response, generates holes and electrons that subsequently diffuse into the HTL 115 and the ETL 125, respectively. The perovskite layer 120 can have a thickness of at least about 250 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 micrometer, 1.25 micrometers, 1.5 micrometers, 1.75 micrometers, 2 micrometers, or more. The perovskite layer 120 can have a thickness of at most about 2 micrometers, 1.75 micrometers, 1.5 micrometers, 1.25 micrometers, 1 micrometer, 900 nm, 800 nm, 700 nm, 600 nm, 500 nm, 400 nm, 300 nm, 250 nm, or less.

[0104] In general, the perovskite layer 120 is composed of a perovskite having a composition represented by the chemical formula MAn1FAn2Csn3PbX3, where MA is methylammonium, FA is formamidinium, Cs is cesium, Pb is lead, and X is a halogen. Methylammonium, formamidinium, and cesium are monovalent cations, lead is a divalent cation, and X is an anion. In general, n1, n2, and n3 can independently be greater than 0 and / or less than 1. In some cases, nl + n2 + n3 can equal 1. For example, nl, n2, and n3 can individually be greater than at least about 0.0001, 0.0005, 0.001, 0.005, 0.01, 0.05, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 0.96, 0.97, 0.98, 0.99, or more. nl, n2, and n3 can individually be less than at most about 0.99, 0.98, 0.97, 0.96, 0.95, 0.9, 0.85, 0.8, 0.75, 0.7, 0.65, 0.6, 0.55, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.14, 0.13, 0.12, 0.11, 0.1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.05, 0.01, 0.005, 0.001, 0.0005, 0.0001, or less. nl, n2, and n3 can individually have a range asAttorney Docket No.54741-0044WO1 defined by any two of the proceeding values. For example, nl can be about 0.001 to about 0.05, n2 can be about 0.8 to about 0.989, and n3 can be about 0.01 to about 0.15.

[0105] In some examples, the perovskite layer 120 is composed of a single cation perovskite having one of methylammonium, formamidinium, or cesium cations. In these cases, the perovskite layer 120 is composed of a methylammonium lead trihalide (CH3NH3PbX3), a formamidinium lead trihalide (H2NCHNH2PbX3), or a cesium lead trihalide (CsPbX3). For example, the perovskite layer 120 can be composed of methylammonium lead triiodide (CH3NH3PbI3). In other examples, the perovskite layer 120 is composed of a double cation perovskite having two of methylammonium, formamidinium, and cesium cations in different ratios. In yet other examples, the perovskite layer 120 is composed of a triple cation perovskite having each of methylammonium, formamidinium, and cesium cations in different ratios. Incorporating cesium into the perovskite lattice can provide enhanced thermodynamic stability. The bandgap of the perovskite layer 120 can be tuned by adjusting the halide content of the perovskite.

[0106] The cations of the proceeding formula include one or more of methylammonium, formamidinium, and cesium. In some examples, the cations can further include butylammonium iodine. The inclusion of the cesium cation (or an equivalent alternate cation) can improve the thermal stability of the perovskite layer 120. For example, the presence of cesium can increase the strength of the molecular bonds of the lead halide structure of the perovskite layer 120. The cesium cations can also have a lower vapor pressure than organic cations, which can contribute to the thermal stability and lower volatility of the perovskite layer 120. The inclusion of formamidinium cations can be more resilient to high temperatures due to their increased molecular weight as compared to other organic cations (e.g., methylammonium). Due to a possible intrinsic instability of a pure formamidinium perovskite, including cesium and / or methylammonium cations can improve the crystalline stability while maintaining thermal stability. Adding too many light organic cations (e.g., methylammonium) can reduce thermal stability. Adding a small percentage of butylammonium iodide can improve the quality of the perovskite layer 120 due to the larger molecular structure of butylammonium being better able to fill the gaps in the perovskite crystalline structure. Butylammonium can help passivate defects or imperfections within the crystal, which can in turn achieves higher quality or performance of the perovskite layer 120. Examples of other cations that can be used in the perovskite layer 120 include, but are not limited to, imidazolium, dimethylammonium, guanidinium, ammonium, methylformamidinium, tetramethyl ammonium, trimethylammonium, rubidium, copper,Attorney Docket No.54741-0044WO1 palladium, platinum, silver, gold, rhodium, ruthenium, sodium, potassium, iron, other inorganic cations, other organic cations, or the like, or any combination thereof.

[0107] In some examples, the perovskite layer 120 is composed of a single halide perovskite. In these cases, X can be one of fluorine, chlorine, bromine, or iodine. For example, X can be iodine. In other examples, the perovskite layer 120 is composed of a mixed halide perovskite. In these cases, X can be a combination of two or more of fluorine, chlorine, bromine, and iodine. For example, X can be a mixture of chlorine and iodine. The combination can include individual components having a concentration of at least about 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, 99, or more percent. The combination can include individual components having a concentration of at most about 99, 98, 97, 96, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, 0.1 or less percent. For example, the combination can be a mixture of about 1% chlorine and 99% iodine. The combination can include individual components having a concentration in a range as defined by any two of the previous values. For example, the combination can be a mixture of about 1% - 5% bromine and about 95% - 99% iodine.

[0108] In some cases, the perovskite layer 120 can be doped with one or more additives including, but not limited to, bromine, cesium iodide, methylammonium chloride, or the like, or any combination thereof. In other cases, the perovskite layer 120 may not be doped with additives. For example, the perovskite layer 120 may not be doped with thiocyanate. In another example, the perovskite layer 120 may not be doped with carbamides. The perovskite layer 120 can be configured to provide high performance and longevity without additives. The lack of additives may provide lower cost and easier manufacturing of the perovskite layer 120.

[0109] In some cases, the perovskite solar cell 240 including said perovskite layer 120 can retain at least about 80% solar conversion efficiency after 300 hours of illumination under one sun conditions in an air atmosphere at 45 °C. For example, the perovskite layer 120 can retain at least about 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 99, or more percent of the initial conversion efficiency value after 300 hours of illumination under one sun conditions in an air atmosphere at >25 °C and <100 °C. The perovskite layer 120 can retain at most about 99, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 14, 13, 12, 11, 10, or less percent of the initial conversion efficiency value after 300 hours of illumination under one sun conditions in an air atmosphere at >25 °C and <100 °C. The perovskite layer 120 can retain a percent of the initial conversionAttorney Docket No.54741-0044WO1 efficiency value after 300 hours of illumination under one sun conditions in an air atmosphere at >25 °C and <100 °C as defined by any two of the proceeding values.

[0110] The ETL 125 is disposed on the perovskite layer 120. The ETL 125 facilitates the transport of electrons from the perovskite layer 120 to the second TCO layer 130 without compromising transparency and conductivity. In contrast, the ETL 125 inhibits hole transport. In some examples, the ETL 125 is composed of phenyl-C61-butyric acid methyl ester (“PCBM”). In other examples, the ETL 125 is composed of another appropriate n-type material described at the end of this disclosure (e.g., C60). The ETL 125 can have a thickness of at least about 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, or more. The ETL 125 can have a thickness of at most about 500 nm, 400 nm, 300 nm, 200 nm, 100 nm, 90 nm, 80 nm, 70 nm, 60 nm, 50 nm, 40 nm, 30 nm, 20 nm, 10 nm, or less. The interface between the ETL 125 and the perovskite layer 120 can be important to the performance of the perovskite layer 120. The surface of the perovskite layer 120 can be hydrophilic to enable good coverage of a hydrophilic ETL (e.g., PCBM). The combination of environment (e.g., low humidity <15%, low temperature from 18 to 24 degrees Celsius) and solvent compatibility can impact the quality of the perovskite layer-ETL connection.

[0111] The second TCO layer 130 is disposed on the ETL 125. The second TCO layer 130 can serve as the negative terminal or anode of the perovskite solar cell 240. In some examples, the second TCO layer 130 is composed of ITO or doped ITO. The second TCO layer 130 can have a thickness of at least about 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, 600 nm, 700 nm, 800 nm, 900 nm, 1 micrometer, or more. The second TCO layer 130 can have a thickness of at most about 1 micrometer, 900 nm, 800 nm, 700 nm, 600 nm, 500 nm, 400 nm, 300 nm, 200 nm, 100 nm, or less. The second TCO layer 130 can have a sheet resistance of at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, or more Ohm / square. The second TCO layer 110 can have a sheet resistance of at most about 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, or less Ohm / square.

[0112] The EIL 150 is disposed on the second TCO layer 130. The EIL 150 can serve as a high-quality vapor barrier film to prevent diffusion of reactive species into or out of the perovskite layer 120. Reactive and other volatile species of the perovskite layer 120 can include water vapor, oxygen, organic cations (e.g., methylammonium, formamidinium, etc.), lead halides, and halide gas. Diffusion pathways for reactive species can be created from lithography features (e.g., P3 scribe lines) inscribed into the second TCO layer 130 andAttorney Docket No.54741-0044WO1 perovskite layer 120 that expose surfaces of the perovskite layer 120 to the environment. The EIL 150 can fill (or otherwise line) the lithography features to passive these surfaces, thereby eliminating such diffusion pathways. In some examples, the EIL 150 is composed of silicon dioxide, titanium dioxide, aluminum oxide, silicon nitride, a polymer (e.g., parylene), or a photopolymer. Examples of photopolymers include acrylate resins, epoxy resins, vinyl ether resins, cationic epoxy resins, polyurethane acrylate resins, polyetheretherketone resins, silicone resins, or the like, or any combination thereof, that are curable (e.g., polymerizable) with ultraviolet light. The EIL 150 can have a thickness of at least about 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, 200 nm, 300 nm, 400 nm, 500 nm, or more. The EIL 150 can have a thickness of at most about 500 nm, 400 nm, 300 nm, 200 nm, 100 nm, 90 nm, 80 nm, 70 nm, 60 nm, 50 nm, 40 nm, 30 nm, 20 nm, 10 nm, or less.

[0113] Referring again to FIG.1A, the first encapsulant 135-1 is disposed on the EIL 150 of the perovskite solar cell 240. The first encapsulant 135-1 can electrically isolate the perovskite solar cell 240 from the silicon solar cell 140. Moreover, the first encapsulant 135-1 can have a relatively high refractive index (e.g., roughly equal to or greater than 1.4) that matches the refractive index of a top silicon nitride or TCO layer of the silicon solar cell 140. Thus, using a high refractive index material(s) can decrease transmission losses between the perovskite solar cell 240, first encapsulant 135-1, and silicon solar cell 140, resulting in improved current density of the tandem solar cell 100. The use of a high refractive index material(s) can also improve light trapping. For example, the first encapsulant 135-1 can include ethylene-vinyl-acetate (“EVA”), thermal-plastic polyolefin (“TPO”), PDMS, silicone, paraffin, polyvinyl butyral, or the like. The first encapsulant 135-1 can also isolate both the perovskite solar cell 240 and the silicon solar cell 140 from the surrounding environment. In combination with the EIL 150, the first encapsulant 135-1 can be configured to prevent volatilization of one or more components of the perovskite layer 120. For example, the first encapsulant 135-1 can minimize loss of organic cations (e.g., methylammonium, formamidinium, etc.) due to heating of the perovskite layer 120. In another example, the first encapsulant 135-1 can reduce the egress of chemical species from the perovskite layer 120 such as lead iodide or other lead halides, the egress of which can result in degraded reliability of the integrated tandem solar cell 100. The first encapsulant 135-1 can be treated to have sufficient cross linking to protect the perovskite layer 120 from water, oxygen, volatilization of the organic compounds of the perovskite layer 120, or the like, or any combination thereof. For example, the first encapsulant 135-1 can be loaded with a desiccant, an oxygen getter, or both to absorb water and / or oxygen vapor that ingresses into the tandem solar cell 100.Attorney Docket No.54741-0044WO1 Examples of desiccants and oxygen getters are described at the end of this disclosure. The first encapsulant 135-1 can have a cross linked percentage of at least about 50, 60, 70, 80, 90, 95, or more percent. The first encapsulant 135-1 can have a cross linked percentage of at most about 95, 90, 80, 70, 60, 50, or less percent. The first encapsulant 135-1 can have a thickness of at least about 100 micrometers (μm), 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 450 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, or more. The first encapsulant 135-1 can have a thickness of at most about 1 mm, 900 μm, 800 μm, 700 μm, 600 μm, 500 μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, or less.

[0114] The silicon solar cell 140 is disposed on the first encapsulant 135-1. In general, the silicon solar cell 140 can be a p-type silicon solar cell with a p-type substrate covered by a thin n-type layer (“emitter”), or it can be an n-type silicon solar cell with an n-type substrate covered by a thin p-type emitter. The silicon solar cell 140 can be a monocrystalline silicon solar cell, a polycrystalline silicon solar cell, a passivated emitter and rear contact (PERC) silicon solar cell, a heterojunction (HJT) silicon solar cell, a heterojunction with intrinsic thin layer (HIT) silicon solar cell, an interdigitated back contact cell (IBC) silicon solar cell, or the like. The silicon solar cell 140 can have a thickness of at least about 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 450 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, or more. The silicon solar cell 140 can have a thickness of at most about 1 mm, 900 μm, 800 μm, 700 μm, 600 μm, 500 μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, or less.

[0115] The second encapsulant 135-2 is disposed on the silicon solar cell 140. The second encapsulant 135-2 can have a relatively high refractive index (e.g., roughly equal to or greater than 1.4) that matches the refractive index of a bottom silicon nitride or TCO layer of the silicon solar cell 140. For example, the second encapsulant 135-2 can include EVA, TPO, PDMS, silicone, paraffin, polyvinyl butyral, or the like. In some examples, the first encapsulant 135-1 is a first layer of an encapsulant 135 and the second encapsulant 135-2 is a second layer of the encapsulant 135. In other words, the first 135-1 and second 135-2 encapsulants may have the same composition. The second encapsulant 135-2 can provide further isolation of the silicon solar cell 140 from the surrounding environment. The second encapsulant 135-2 can be treated to have sufficient cross linking to protect the silicon solar cell 140 from water, oxygen, or the like. For example, the second encapsulant 135-2 can be loaded with a desiccant, an oxygen getter, or both to protect the silicon solar cell 140 from ingress water and oxygen vapor. The second encapsulant 135-2 can have a cross linkedAttorney Docket No.54741-0044WO1 percentage of at least about 50, 60, 70, 80, 90, 95, or more percent. The second encapsulant 135-2 can have a cross linked percentage of at most about 95, 90, 80, 70, 60, 50, or less percent. The second encapsulant 135-2 can have a thickness of at least about 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 450 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, or more. The second encapsulant 135-2 can have a thickness of at most about 1 mm, 900 μm, 800 μm, 700 μm, 600 μm, 500 μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, or less.

[0116] The back sheet 145 is disposed on the second encapsulant 135-2. In some examples, the second encapsulant 135-2 can be omitted, such that silicon solar cell 140 is disposed directly on the back sheet 145, e.g., fabricated on the back sheet 145. The back sheet 145 seals the tandem solar cell 100 to prevent moisture ingress. The back sheet 145 can have a thickness of at least about 2.0 mm, 2.5 mm, 3.0 mm, 3.5 mm, 4.0 mm, 4.5 mm, 5.0 mm, or more. The back sheet 145 can have a thickness of at most about 5.0 mm, 4.5 mm, 4.0 mm, 3.5 mm, 3.0 mm, 2.5 mm, 2.0 mm, or less. The back sheet has a top surface 146T and a bottom surface 146B. In some cases, the back sheet 145 is composed of a thermoplastic elastomer or a thermoplastic polymer such as polyethylene terephthalate. In other cases, the back sheet 145 is a glass sheet. The top surface 146T of the glass sheet 145 can have a highly reflective coating or textured surface to further increase light trapping or scattering back into the tandem solar cell 100. The glass sheet 145 can be transparent. The glass sheet 145 can be substantially transparent. The transparency of the glass sheet 145 can facilitate bifacial operation of the tandem solar cell 100. For example, the tandem solar cell 100 can be configured to absorb light from both sides of the tandem solar cell 100.

[0117] The perovskite solar cell 240 and the silicon solar cell 140 can be electrically isolated from each other, and each of the perovskite 240 and silicon 140 solar cells can have its own terminals. That is, the tandem solar cell 100 can be a four-terminal terminal solar cell with each of the perovskite 240 and silicon 140 solar cells having two respective terminals. The perovskite solar cell 240 and the silicon solar cell 140 can be connected in series or parallel by connecting the terminals in the appropriate manner. In the case of a series connection, the perovskite solar cell 240 and the silicon solar cell 140 can be current- matched. In the case of a parallel connection, the perovskite solar cell 240 and the silicon solar cell 140 can be voltage matched. Laser scribing can be used to achieve the current matching or voltage matching, e.g., by connecting individually scribed perovskite subcells in series or parallel to achieve a desired voltage or current. Parallel or series connection between the perovskite solar cell 240 and the silicon solar cell 140 can be made via busbars orAttorney Docket No.54741-0044WO1 electrodes before lamination of the tandem solar cell 100. This allows rapid and easy introduction into any existing silicon manufacturing process.

[0118] In some cases, see FIGs.3A-4D for example, a tandem solar module 10 containing multiple such tandem solar cells 100 can have a power conversion efficiency of at least about 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, or more. In some examples, the tandem solar module 10 can have a T80 time of at least about 4 years, 5 years, 6 years, 7 years, 8 years, 9 years, 10 years, 11 years, 12 years, 13 years, 14 years, 15 years, 16 years, 17 years, 18 years, 19 years, 20 years, 21 years, 22 years, 23 years, 24 years, 25 years, or more. For example, the tandem solar module 10 can have a T80 time of about 12 years or more. As another example, the tandem solar module 10 can have a T80 time of about 15 years or more. The T80 time refers to the total time elapsed for the power output of a solar module to degrade to 80% of its initial one sun output capacity in an air atmosphere at >25 °C and <100 °C. Hence, a longer T80 time indicates a slower degradation rate and higher durability of the tandem solar module 10. The tandem solar module 10 and tandem solar cells 100 contained therein can be fabricated through methods described with reference to FIG.7. Further details relating to such manufacturing methods are described in Int’l. Appl. No. PCT / US2021 / 051465, filed September 22, 2021, and titled “Methods and Devices for Integrated Tandem Solar Module Fabrication,” which is incorporated herein by reference in its entirety for all purposes.

[0119] FIGs.2A-2B schematically illustrate an example of a perovskite solar cell 240. The perovskite solar cell 240 is segmented into multiple perovskite subcells 242 by P1, P2, P3, and P4 scribe lines. The perovskite solar cell 240 is disposed on a surface 106B of a substrate 105, e.g., a bottom surface of a top glass sheet. The perovskite solar cell 240 is configured according to FIG.1B and includes a first TCO layer 110, a HTL 115, a perovskite layer 120, an ETL 125, a second TCO layer 130, and an EIL 150 stacked on top of one another.

[0120] FIG.2A is an inverted view of the perovskite solar cell 240 showing the transverse configuration of the P1, P2, P3, and P4 scribe lines. The perovskite solar cell 240 is segmented into multiple long perovskite subcells 241 by sets of P1, P2, and P3 scribe lines. The sets of P1, P2, and P3 scribe lines form serial interconnections between the long perovskite subcells 241, referred to as “monolithic integration”. This design can limit the total current flowing through the TCO layers 110 and 130, thereby limiting resistive losses in the TCO layers 110 and 130. The perovskite solar cell 240 further includes P4 scribe lines that can be configured to mitigate the effects of defects in any one long perovskite subcellAttorney Docket No.54741-0044WO1 241. Defects can reduce the power conversion efficiency and long-term stability of the perovskite solar cell 240.

[0121] The P1, P2, and P3 scribe lines are parallel to one another and segment the perovskite solar cell 240 into columns of long perovskite subcells 241 that are series connected to one another. The P4 scribe lines are perpendicular to the P1, P2, and P3 scribe lines, segmenting the long perovskite subcells 241 into shorter ones. The shorter perovskite subcells 242 belonging to the same long subcell 241 can be connected in parallel with one another. This technique reduces the impact of a defect as it can be isolated to a smaller perovskite subcell 242 without compromising an entire long perovskite subcell 241. The perovskite solar cell 240 further includes an anode terminal 244A and a cathode terminal 244C each extending along a respective edge of the perovskite solar cell 240. The terminals 244A and 244C interface with the second 130 TCO layer and first TCO layer 110, respectively, to collect current from the long perovskite subcells 241. The terminals 244A and 244C can be configured to output power and / or connect with a silicon solar cell 140 in series or parallel as described elsewhere herein.

[0122] FIG.2B is an inverted cross-sectional side view (Section A-A’) of the perovskite solar cell 240 showing the longitudinal configuration of the P1, P2, and P3 scribe lines. The P1, P2, and P3 scribe lines correspond to respective gaps extending through one or more layers of the perovskite solar cell 240. The overlapping layers are deposited into the gaps to form contacts.

[0123] The P1 scribe line corresponds to a gap extending through the first TCO layer 110 and HTL 115. The P1 scribe line is filled (or otherwise lined) by the perovskite layer 120. The P1 scribe line electrically isolates the first TCO layer 110 between two contiguous perovskite subcells 242-N and 242-(N+1).

[0124] The P2 scribe line corresponds to a gap extending through the HTL 115, perovskite layer 120, and ETL 125. The P2 scribe line is filled (or otherwise lined) with the second TCO layer 130. The P2 scribe line provides a channel to connect the first TCO layer 110 of the first perovskite subcell 242-N to the second TCO layer 130 of the second perovskite subcell 242-(N+1), forming an interconnection therebetween.

[0125] The P3 scribe line corresponds to a gap extending through the HTL 115, perovskite layer 120, ETL 125, and second TCO layer 130. The P3 scribe line is filled (or otherwise lined) with the EIL 150. The P3 scribe line electrically isolates the second TCO layer 130 between the two contiguous perovskite subcells 242-N and 242-(N+1). However, the P3 scribe line can expose surfaces 122 of the perovskite layer 120 to the environment,Attorney Docket No.54741-0044WO1 thereby providing diffusion pathways of reactive species into or out of the perovskite layer 120, such as water vapor, oxygen, organic cations (e.g., methylammonium, formamidinium, etc.), and the like. The EIL 150 serves as a high-quality vapor barrier to passivate the surfaces 122 and prevent ingress or egress of such reactive species.

[0126] The P4 scribe line (not shown in FIG.2B) corresponds to a gap extending through each of the layers, including the first TCO layer 110, HTL 115, perovskite layer 120, ETL 125, and second TCO layer 130, thereby exposing the substrate 105. Like the P3 scribe line, the P4 scribe line exposes surfaces 122 of the perovskite layer 120 to the environment, thereby providing diffusion pathways of reactive species into or out of the perovskite layer 120, such as water vapor, oxygen, organic cations (e.g., methylammonium, formamidinium, etc.), and the like. The EIL 150 serves as a high-quality vapor barrier to passivate the surfaces 122 and prevent ingress or egress of such reactive species.

[0127] The P1, P2, P3, and P4 scribe lines can be fabricated by lithography operations (e.g., laser scribing) through methods described with reference to FIG.7.

[0128] FIGs.3A-3C schematically illustrate an example of a tandem silicon-perovskite solar module 10. The tandem solar module 10 includes a top glass sheet 105, a perovskite photovoltaic 24 including an array of perovskite solar cells 240, a first encapsulant 135-1, a silicon photovoltaic 14 including an array of silicon solar cells 140, a second encapsulant 135-2, and a back sheet 145 stacked on top of one another. The solar module 10 further includes a junction box 155 positioned on an underside of the solar module 10.

[0129] FIG.3A is an exploded isometric view of the tandem solar module 10. Each pair of silicon 140 and perovskite 240 solar cells forms a respective tandem solar cell 100 configured in accordance with FIGs.1A-1B. The perovskite solar cell 240 and silicon solar cell 140 in a tandem solar cell 100 can be connected in parallel or series to the junction box 155 via metallic busbars or terminals as described elsewhere herein. In some examples, the tandem solar module 10 includes 32, 36, 48, 60, 72, 96, or 144 tandem solar cells 100 corresponding to the form factor of a conventional 32-cell, 36-cell, 48-cell, 60-cell, 72-cell, 96-cell, or 144-cell silicon solar panel, where the silicon solar cells 140 are the solar cells of the silicon solar panel. In some examples, the back sheet 145 is a glass sheet. As the perovskite photovoltaic 24 can be sensitive to water and oxygen vapor, the combination of the two glass sheets 105 and 145 may be a preferred laminate construction of the tandem solar module 10, e.g., to provide a better hermetic seal than a glass sheet 105 and polymer- based back sheet 145 laminate construction. A glass-glass lamination also has the advantage of mechanical-breakage protection of the silicon photovoltaic 14 due to the symmetric natureAttorney Docket No.54741-0044WO1 of the tandem solar module 10. For example, if the silicon photovoltaic 14 is arranged near (or in) the neutral plane of the tandem solar module 10, it will experience little (or no) tensile stress when a force is applied to the tandem solar cell 100, e.g., from wind stress, or an installer manipulating or stepping on the solar module 10.

[0130] FIG.3B is a top view of the tandem solar module 10. FIG.3C is an inverted cross- sectional side view (Section A-A’) of the tandem solar module 10 showing the top glass sheet 105, a perovskite solar cell 240 of the perovskite photovoltaic 24, the encapsulant 135, and the back sheet 145. Note, the silicon photovoltaic 14 disposed between the two layers of the encapsulant 135-1 and 135-2 is omitted from FIG.3C for clarity.

[0131] The tandem solar module 10 is encapsulated with an edge seal 160 and a metallized tape 170 to reduce water-assisted and dry oxidation of the perovskite solar cells 240 contained therein, which can be the dominate degradation mechanisms of the perovskite layer 120. While the encapsulant 135 helps mitigate such oxidization mechanisms, it generally does not altogether eliminate them. For example, methylammonium lead triiodide(CH3NH3PbI3) oxidizes in the presence of oxygen (O ) in accordance with the followingchemical equation:4CH NH PbI + O 4PbI + 2I + 2H O + CH NH ,

[0132] which generates crystallized lead(II) iodide (PbI ), iodine gas (I ), water vapor(H O), and methylamine gas (CH3NH2) as byproducts. In some cases, the edge seal 160 andmetallized tape 170 may be capable of eliminating water-assisted and dry oxidation as the dominate forms of degradation of the perovskite solar cell 240. In other cases, see FIGs.4A- 4D for example, the edge seal 160 and metallized tape 170 can be combined with an oxygen gettering system 180 arranged within the lamination of the solar module 10 to eliminate water-assisted and dry oxidation as the dominate degradation mechanisms.

[0133] The edge seal 160 is disposed between the bottom surface 106B of the top glass sheet 105 and the top surface 146T of the back sheet 145. The edge seal 160 is arranged laterally about the perovskite photovoltaic 24, the silicon photovoltaic 14, and the encapsulant 135. The edge seal 160 circumscribes the perimeter of the tandem solar module 10 to prevent ingress of water and oxygen vapor. The encapsulant 135 fills the interior space of the solar module 10 formed between an interior surface 161I of the edge seal 160, the bottom surface 106B of the top glass sheet 105, and the top surface 146T of the back sheet 145. The encapsulant 135 surrounds the perovskite 24 and silicon 14 photovoltaics and is contact with interior surface 161I of the edge seal 160. A lateral surface 106L of the top glassAttorney Docket No.54741-0044WO1 sheet 105, a lateral surface 146L of the back sheet 145, and a lateral surface 161L of the edge seal 160 are aligned with another to provide a flush edge for the solar module 10.

[0134] The material composition of the edge seal 160 can be selected to provide a low vapor transmission rate, e.g., a water and / or oxygen vapor transmission rate, thereby reducing diffusion of water and / or oxygen vapor into the solar module 10. For example, the edge seal 160 can be composed of PDMS, HelioSeal™, silicon glue, a butyl-based sealant, or the like. As another example, the edge seal 160 can be composed of a polymer such as polyisobutylene, polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyethersulfone, polyethylene naphthalate, polyimide, or the like. As a particular example, the edge seal 160 can be composed of polyisobutylene. In some examples, the edge seal 160 is loaded with a desiccant, an oxygen getter, or both to further mitigate water and / or oxygen vapor ingress. Moreover, increasing the width of the edge seal 160 can further reduce the vapor transmission rate of the edge seal 160. For example, the edge seal 160 can have a width of at least about 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm, 31 mm, 32 mm, 33 mm, 34 mm, 35 mm, or more. The edge seal 160 can have a width of at most about 35 mm, 34 mm, 33 mm, 32 mm, 31 mm, 30 mm, 29 mm, 28 mm, 27 mm, 26 mm, 25 mm, 24 mm, 23 mm, 22 mm, 21 mm, 20 mm, 19 mm, 18 mm, 17 mm, 16 mm, 15 mm, 14 mm, 13 mm, 12 mm, 11 mm, 10 mm, 9 mm, 8 mm, 7 mm or less. The edge seal 160 has a thickness corresponding to the distance between the bottom surface 106B of the top glass sheet 105 and the top surface 146T of the back sheet 145. For example, the edge seal 160 can have a thickness of at least about 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 350 μm, 400 μm, 450 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, or more. The edge seal 160 can have a thickness of at most about 1 mm, 900 μm, 800 μm, 700 μm, 600 μm, 500 μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, or less.

[0135] The metallized tape 170 includes a metal layer 172, a polymer layer 174, and an adhesive layer 176. The metalized tape 170 can be sectioned into multiple strips or applied as a single strip to the solar module 10. The polymer layer 174 is disposed on the metal layer 172, and the adhesive layer 176 disposed on the polymer layer 174 to provide adhesion to the solar module 10. In some examples, the metallized tape 170 may not include the polymer layer 174, such that the adhesive layer 176 is disposed directly on the metal layer 172. In some examples, the metallized tape 170 can also include one or more additional (e.g., protective) layers disposed on the metal layer 172. The metallized tape 170 is adhered to theAttorney Docket No.54741-0044WO1 lateral surface 106L of the top glass sheet 105, the lateral surface 146L of the back sheet 145, and the lateral surface 161L of the edge seal 160. The metallized tape 170 is further adhered and extends onto the top surface 106T of the top glass sheet 105 and the bottom surface 146B of the back sheet 145. This configuration of the metallized tape 170 furthers reduce the rate of water and oxygen ingress through the edge of the solar module 10. In this example, the metallized tape 170 extends a distance about equal to the width of the edge seal 160, at least doubling the effective length through which vapor diffuses into the solar module 10. This is shown by the total diffusive flux of water or oxygen vapor through the polymer 174 andadhesive 176 layers of the metallized tape 170:

[0136] where is the diffusion constant of the vapor, is the effective cross-sectional area through which vapor diffuses, is the difference in concentration of the vapor outside and inside the solar module 10, and is the width of the edge seal 170. For example, the metallized tape 170 can extend at least about 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm, 25 mm, 26 mm, 27 mm, 28 mm, 29 mm, 30 mm, 31 mm, 32 mm, 33 mm, 34 mm, 35 mm, or more onto the top surface 106T of the top glass sheet 105 and the bottom surface 146B of the back sheet 145. The metallized tape 170 can extend at most about 35 mm, 34 mm, 33 mm, 32 mm, 31 mm, 30 mm, 29 mm, 28 mm, 27 mm, 26 mm, 25 mm, 24 mm, 23 mm, 22 mm, 21 mm, 20 mm, 19 mm, 18 mm, 17 mm, 16 mm, 15 mm, 14 mm, 13 mm, 12 mm, 11 mm, 10 mm, 9 mm, 8 mm, 7 mm, or less onto the top surface 106T of the top glass sheet 105 and the bottom surface 146B of the back sheet 145.

[0137] The metal layer 172 can be composed of aluminum, gold, silver, copper, nickel, chromium, steel, zinc, or the like. The metal layer 172 can have a thickness of at least about 1 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, or more. The metal layer 172 can have a thickness of at most about 50 μm, 45 μm, 40 μm, 35 μm, 30 μm, 25 μm, 20 μm, 15 μm, 10 μm, 5 μm, 1 μm, or less.

[0138] The polymer layer 174 can be composed of a polymer with a low water and / or oxygen vapor transmission rate. For example, the polymer layer 174 can be composed of polyisobutylene, polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyethersulfone, polyethylene naphthalate, polyimide, or the like. In some examples, the polymer layer 174 is loaded with a desiccant, an oxygen getter, or both. The polymer layer 174 can have a thickness of at least about 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35Attorney Docket No.54741-0044WO1 μm, 40 μm, 45 μm, 50 μm, or more. The polymer layer 174 can have a thickness of at most about 50 μm, 45 μm, 40 μm, 35 μm, 30 μm, 25 μm, 20 μm, 15 μm, 10 μm, 5 μm, or less.

[0139] The adhesive layer 176 can be composed of an acrylic adhesive or other suitable adhesive. In some examples, the adhesive layer 176 is loaded with a desiccant, an oxygen getter, or both. The adhesive layer 176 can have a thickness of at least about 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, or more. The adhesive layer 176 can have a thickness of at most about 50 μm, 45 μm, 40 μm, 35 μm, 30 μm, 25 μm, 20 μm, 15 μm, 10 μm, 5 μm, or less.

[0140] FIGs.4A-4D schematically illustrate additional examples of the tandem solar module 10A-10D encapsulated with the edge seal 160, the metallized tape 170, and different types of oxygen gettering systems 180A-180D included in the lamination of the solar module 10. The oxygen gettering systems 180A-180D and are configured to remove residual oxygen vapor from the interior of the solar module 10 that manages to diffuse through the edge seal 160 and metallized tape 170. FIGs.4A and 4B show examples of oxygen gettering system 180A and 180B that generate innocuous byproducts for the perovskite photovoltaic 24 when capturing oxygen. FIGs.4C and 4D show examples of oxygen gettering system 180C and 180D that generate deleterious byproducts (e.g., water vapor) for the perovskite photovoltaic 24 when capturing oxygen, which are subsequently compensated for.

[0141] FIG.4A is an inverted cross-sectional side view (Section A-A’) of the tandem solar module 10A showing the top glass sheet 105, the perovskite solar cell 240, the encapsulant 135, the back sheet 145, the edge seal 160, the metallized tape 170, and a first type of oxygen gettering system 180A. The oxygen gettering system 180A includes a first type of sacrificial material 182A disposed on the bottom surface 106B of the top glass sheet 105. The sacrificial material 182A is arranged laterally about the perovskite photovoltaic 24 of the solar module 10. For example, the sacrificial material 182A can be a rectangular ring that is concentric with the edge seal 160. The sacrificial material 182A is positioned between the interior surface 161I of the edge seal 160 and the perovskite photovoltaic 24 such that the encapsulant 135 surrounds the sacrificial material 182A.

[0142] In this example, the sacrificial material 182A includes an oxygen getter that generates innocuous byproducts when combining with oxygen. For example, the oxygen getter can be a reduced metal (e.g., copper) that generates one or more oxides (e.g., copper oxides) when combining with oxygen. The sacrificial material 182 can be composed of the oxygen getter or loaded with the oxygen getter. For example, the sacrificial material 182 can be in the form of a porous monolith or as a powder of the oxygen getter. Alternatively, theAttorney Docket No.54741-0044WO1 sacrificial material 182 can be a host medium loaded with a powder of the oxygen getter. For example, the host medium can be a polymer having the powder of the oxygen getter suspended therein. Examples of polymers include any of those listed above for the edge seal 160. As another example, the host medium can be a gel or liquid solution having the powder of the oxygen getter suspended therein. In general, the powder of the oxygen getter has an average particle size (e.g., an average particle diameter) less than the thickness of the host medium. Examples of particle sizes for a powder of an oxygen getter are provided at the end of this specification. The sacrificial material 182 can have a width of at least about 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or more. The sacrificial material 182 can have a width of at most about 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, or less. The sacrificial material 182 can have a thickness of at least about 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 350 μm, 400 μm, 450 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, or more. The sacrificial material 182 can have a thickness of at most about 1 mm, 900 μm, 800 μm, 700 μm, 600 μm, 500 μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, or less.

[0143] FIG.4B is an inverted cross-sectional side view (Section A-A’) of the tandem solar module 10B showing the top glass sheet 105, the perovskite solar cell 240, the encapsulant 135, the back sheet 145, the edge seal 160, the metallized tape 170, and a second type of oxygen gettering system 180B. The oxygen gettering system 180B includes the sacrificial material 182A and a confinement well 183 disposed on the bottom surface 106B of the top glass sheet 105, where the sacrificial material 182A is positioned within the confinement well 183. For example, if the sacrificial material 182A is in the form of a powder of an oxygen getter or a solution loaded with a powder of the oxygen getter, the confinement well 183 can confine the sacrificial material 182A to a particular interior region of the solar module 10. Alternatively, or in addition, the confinement well 183 can provide a stable structure for depositing the sacrificial material 182 on the top glass sheet 105 during formation of the perovskite photovoltaic 24.

[0144] The confinement well 183 includes an inner portion 183I and an outer portion 183O. The inner portion 183I is arranged laterally about the perovskite photovoltaic 24 of the solar module 10 and the outer portion 183O is arranged laterally about the inner portion 183I. For example, the inner 183I and outer 183O portions of the confinement well 183 can be rectangular rings concentric that are concentric with the edge seal 160. The sacrificial material 182 is positioned (e.g., deposited) between the inner 183I and outer 183O portions of the confinement well 183. The confinement well 183 is positioned between the interiorAttorney Docket No.54741-0044WO1 surface 161I of the edge seal 160 and the perovskite photovoltaic 24 such that the encapsulant 135 surrounds the confinement well 183 and sacrificial material 182 positioned therein. In some examples, the confinement well 183 is composed of a polymer. Examples of polymers include any of those listed above for the edge seal 160. The confinement well 183 can have a thickness of at least about 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 350 μm, 400 μm, 450 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, or more. The confinement well 183 can have a thickness of at most about 1 mm, 900 μm, 800 μm, 700 μm, 600 μm, 500 μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, or less. The inner 183I and outer 183O portions of the confinement well 183 can each have a width of at least about 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or more. The inner 183I and outer 183O portions of the confinement well 183 can each have a width of at most about 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, or less.

[0145] FIG.4C is an inverted cross-sectional side view (Section A-A’) of the tandem solar module 10C showing the top glass sheet 105, the perovskite solar cell 240, the encapsulant 135, the back sheet 145, the edge seal 160, the metallized tape 170, and a third type of oxygen gettering system 180C. The oxygen gettering system 180C includes a second type of sacrificial material 182B and an absorber material 184 disposed between the bottom surface 106B of the top glass sheet 105 and the top surface 146B of the back sheet 145. The absorber material 184 is arranged laterally about the perovskite photovoltaic 24 of the solar module 10 and the sacrificial material 182B is arranged laterally about the absorber material 184. Here, the sacrificial material 182B is in contact with the absorber material 184 and the interior surface 161I of the edge seal 160 to remove pockets of vacant space in the solar module 10.

[0146] In this example, the sacrificial material 182B includes an oxygen getter that generates deleterious byproducts, in this case water vapor, when combining with oxygen. Such situations can occur when the sacrificial material 182B includes an oxygen getter composed of a perovskite (e.g., methylammonium lead triiodide). For example, the oxygen getter can be composed of the same perovskite as the perovskite layer 120. The use of a sacrificial perovskite within the laminate of the solar module 10C has an additional benefit besides reacting with oxygen – it will evolve vapor of volatile halides such as methylammonium halides, which will reduce the evaporation of such halides from the perovskite solar cell 240. The oxygen getter can be dispersed within a polymer medium. In the case that the powder is dispersed in a polymer or other host medium, it can be of anyAttorney Docket No.54741-0044WO1 diameter less than the thickness of the host medium. The absorber material 184 includes a desiccant and is configured to absorb the water vapor generated by the sacrificial material 182B. The absorber material 184 can be composed of the desiccant or loaded with the desiccant. For example, the absorber material 184 can be in the form of a porous monolith or a powder of the desiccant. Alternatively, the absorber material 184 can be a host medium loaded with the desiccant. For example, the host medium can be a polymer having the powder of the desiccant suspended therein. Examples of polymers include any of those listed above for the edge seal 160. As another example, the host medium can be a gel or liquid solution having the powder of the desiccant suspended therein. The absorber material 184 can have a width of at least about 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, or more. The absorber material 184 can have a width of at most about 10 mm, 9 mm, 8 mm, 7 mm, 6 mm, 5 mm, 4 mm, 3 mm, 2 mm, 1 mm, or less. The absorber material 184 can have a thickness of at least about 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 350 μm, 400 μm, 450 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, or more. The absorber material 184 can have a thickness of at most about 1 mm, 900 μm, 800 μm, 700 μm, 600 μm, 500 μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, or less.

[0147] FIG.4D is an inverted cross-sectional side view (Section A-A’) of the tandem solar module 10D showing the top glass sheet 105, the perovskite solar cell 240, the back sheet 145, the edge seal 160, the metallized tape 170, and a fourth type of oxygen gettering system 180D. The oxygen gettering system 180D includes a layer of the absorber material 184 and a layer of the sacrificial material 182B. The layer of the absorber material 184 is disposed on the perovskite photovoltaic 24 and the bottom surface 106B of the top glass sheet 105. The layer of the sacrificial material 182B is disposed on the layer of the absorber material 184. Although not shown in FIG.4D, the absorber material 184 may be located anywhere between the sacrificial material 182B and the perovskite cell 240. The arrangement in FIG.4D, when using a perovskite sacrificial material, has the advantage of distributing halide vapor throughout the span of the entire device surface, to combat diffusion of such vapor out of the perovskite solar cell 240. The layer of the absorber material 184 surrounds the perovskite photovoltaic 24 such that the layers of the sacrificial 182B and absorber 184 materials are in contact with the interior surface 161I of the edge seal 160. Although not shown in FIG.4D, the encapsulant 135 can be disposed on the layer of the sacrificial material 182B. The layer of the sacrificial material 182B can have a thickness of at least about 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 350 μm, 400 μm, 450 μm, 500 μm, 600Attorney Docket No.54741-0044WO1 μm, 700 μm, 800 μm, 900 μm, 1 mm, or more. The layer of the sacrificial material 182B can have a thickness of at most about 1 mm, 900 μm, 800 μm, 700 μm, 600 μm, 500 μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, or less. The layer of the absorber material 184 can have a thickness of at least about 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 350 μm, 400 μm, 450 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1 mm, or more. The layer of the absorber material 184 can have a thickness of at most about 1 mm, 900 μm, 800 μm, 700 μm, 600 μm, 500 μm, 450 μm, 400 μm, 350 μm, 300 μm, 250 μm, 200 μm, 150 μm, 100 μm, or less.

[0148] FIG.5 is a flowchart of an example fabrication process 300 for forming a perovskite photovoltaic on a substrate (e.g., perovskite-on-glass).

[0149] The process 300 includes providing the substrate (310). The substrate can be a transparent substrate. The substrate can include a silicon-based glass (e.g., an amorphous silicon dioxide, a doped silicon dioxide, etc.), a transparent conductive oxide, a ceramic, a chalcogenide glass, a polymer (e.g., a transparent plastic, poly(methyl methacrylate, etc.), or the like, or any combination thereof. The substrate can include a top surface of a solar module. For example, the substrate can be a top glass sheet of a silicon solar panel assembly. The substrate can be textured and / or patterned. For example, the substrate can include nano- scale texturing configured as an antireflective coating and an adhesion surface. In another example, the substrate can include patterning configured to generate photonic channels. In another example, the substrate can include pre-patterned portions with electrodes for removing energy from the solar cell (e.g., a top contact grid layout). The substrate can have an area of at least about 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, or more square meters. The substrate can have an area of at most about 25, 20, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, 0.1, or fewer square meters. The substrate can be a large format substrate. For example, the substrate can be a 10th generation substrate.

[0150] The process 300 includes applying a first transparent conducting layer to the substrate (320). The first transparent conducting layer can include a transparent conductive oxide (e.g., indium tin oxide (ITO), indium zinc oxide, aluminum zinc oxide, indium cadmium oxide, etc.), a transparent conductive polymer (e.g., poly(3,4- ethylenedioxythiophene) (PEDOT), poly(3,4- ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), poly(4,4-dioctyl cyclopentadithiophene), etc.), carbon nanotubes, graphene, nanowires (e.g., silver nanowires), metallic grids (e.g., grid contacts including metals), thin films (e.g., thin metal films), conductive grain boundaries, or the like, or any combination thereof. The first transparent conducting layer can have a full spectrumAttorney Docket No.54741-0044WO1 transparency of at least about 20%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.9%, or more. The first transparent conducting layer can have a full spectrum transparency of at most about 99.9%, 99%, 98%, 97%, 96%, 95%, 90%, 85%, 80%, 75%, 70%, 60%, 50%, 40%, 30%, 20%, or less. The first transparent conducting layer can have a full spectrum transparency in a range as defined by any two of the proceeding values. For example, the first transparent conducting layer can have a full spectrum transparency of 75% to 85%. The first transparent conducting layer can have a transparency over a spectral band of at least about 20%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.9%, or more. The first transparent conducting layer can have a transparency over a spectral band of at most about 99.9%, 99%, 98%, 97%, 96%, 95%, 90%, 85%, 80%, 75%, 70%, 60%, 50%, 40%, 30%, 20%, or less. For example, the first transparent conducting layer can have a transmission of 85% or more over the wavelength range from 400 nm to 1200 nm. The first transparent conducting layer can function as a vapor barrier to a perovskite layer for moisture, gas, dust, and the like. The first transparent conducting layer can also prevent the diffusion of ions (e.g., metal ions) which may impact the performance of the perovskite layer.

[0151] The process 300 includes applying a hole transport layer to the first transparent conducting layer (330). The hole transport layer can be applied by deposition methods as described elsewhere herein (e.g., physical vapor deposition, ultrasonic spray-on, etc.). The hole transport layer can include a material with a valance band maximum less than that of a perovskite layer. For example, if the perovskite layer has a valence band maximum of -5.4 eV, the hole transport layer can have a valence band maximum of -5.2 eV. The hole transport layer can include organic molecules (e.g., 2, 2', 7,7'- Tetrakis[N,N-di(4- methoxyphenyl)amino]-9,9'-spirobifluorene (Spiro-OMeTAD)), inorganic oxides (e.g., nickel oxide (NiOx), copper oxide (CuOx), cobalt oxide (CoOx), chromium oxide (CrOx), vanadium oxide (VOx), tungsten oxide (WOx), molybdenum oxide (MoOx), copper aluminum oxide (CuAlO2), copper chromium oxide (CuCrO2), copper gallium oxide (CuGaO2), etc.), inorganic chalcogenides (e.g., copper iodide (Cui), copper indium sulfide (CuInS2), copper zinc tin sulfide (CuZnSnS4), cupper barium tin sulfide (CuBaSnS4), etc.) other inorganic materials (e.g., copper thiocyanate (CuSCN), etc.), organic polymers, or the like, or any combination thereof. For example, a glass substrate covered in indium tin oxide (ITO) can be coated with nickel oxide (NiO) to form a hole transport layer on the first transparent conducting layer.Attorney Docket No.54741-0044WO1

[0152] Operation 330 can optionally include performing one or more lithography operations on the hole transport layer. The one or more lithography operations can include optical lithography (e.g., (extreme) ultraviolet lithography, x-ray lithography, laser scribing, etc.), electron beam lithography, ion beam lithography, nanoimprint lithography, other direct writing processes (e.g., dip-pen lithography, inkjet printing), or the like, or any combination thereof. The one or more lithography operations can include the addition and / or subtraction of features. For example, features can be cured and made permanent. In another example, features can be formed by the removal of material from the target.

[0153] The process 300 includes scribing P1 scribe lines through the hole transport layer and the first transparent conducting layer (335). The purpose of operation 335 is to ablate portions of the first transparent conducting layer, typically in thin lines, to begin the definition of serial perovskite subcells. Operation 335 can be achieved by mechanical means, or via laser scribing methods using ultraviolet light, visible light, or infrared light generated from a laser (e.g., a continuous wave or pulsed laser).

[0154] The process 300 includes applying a perovskite precursor to the hole transport layer (340). The perovskite precursor can also have one or more additives dissolved therein. The addition of the one or more additives can be configured to reduce and / or eliminate defects within perovskite layers as prepared elsewhere herein. For example, the one or more additives can include one or more of bromine, cesium iodide, or methylammonium chloride. Alternatively, or in addition, the one or more additives can include one or more recrystallization solvents. The one or more recrystallization solvents can be added to a solution including the perovskite precursor. The one or more recrystallization solvents can be applied after deposition of the perovskite precursor and / or after an annealing of the perovskite precursor. For example, a lead halide precursor can be applied and subsequently a recrystallization solvent can be applied, and the perovskite precursor can be further annealed to orient the lead halide precursor for better methylammonium iodide integration. Examples of recrystallization solvents include, but are not limited to, halobenzenes (e.g., chlorobenzene, bromobenzene, etc.), haloforms (e.g., chloroform, iodoform, etc.), ethers (e.g., diethyl ether), or the like, or any combination thereof.

[0155] For one-step deposition of the perovskite precursor, the perovskite precursor (or a solution including the perovskite precursor) can be applied to the hole transport layer via a solvent or liquid coating technique, such as a blade coating, roll-coating, or slot-die coating technique. In other implementations, the perovskite precursor can be applied using techniques such as chemical vapor deposition (CVD), plasma enhanced CVD, atomic layer deposition,Attorney Docket No.54741-0044WO1 spin coating, dip coating, doctor blading, drop casting, centrifugal casting, chemical solution deposition, sol-gel deposition, plating, physical vapor deposition, thermal evaporation, molecular beam epitaxy, sputtering, pulsed laser deposition, cathodic arc deposition, ultrasonic spray-on, thermal spray-on, inkjet printing, or the like, or any combination thereof. Other layers of the perovskite photovoltaic can also be deposited using such methods, including the first transparent conducting layer, the hole transport layer, an electron hole layer, a second transparent conducting layer, and an electrically insulating layer.

[0156] In general, the perovskite precursor can include one or more lead halides (e.g., lead fluoride, lead chloride, lead bromide, lead iodide, etc.), lead salts (e.g., lead acetates, lead oxides, etc.), other metal salts (e.g., manganese halides, tin halides, metal oxides, metal halides, etc.), organohalides (e.g., formamidinium chloride, formamidinium bromide, formamidinium iodide, methylammonium chloride, methylammonium bromide, methylammonium iodide, butylammonium halides, etc.), alkali metal salts (e.g., alkali metal halides, etc.), alkali earth metal salts (e.g., alkali earth metal halides, etc.), perovskite nanoparticles, or the like, or any combination thereof.

[0157] The perovskite precursor can be in a solution with one or more additional perovskite precursors. For example, both methylammonium iodide and butylammonium iodide can be used as perovskite precursors in the solution. In this example, methylammonium iodide can be at about a 1:99, 10:90, 20:80, 30:70, 40:60, 50:50, 60:40, 70:30, 80:20, 10:90, or 99:1 ratio with butylammonium iodide. In another example, mixtures of lead halides can be used in the solution. Using different mixtures of lead halides can permit tuning of the bandgap of the photoactive layer. For example, using different mixtures of lead (II) bromide and lead (II) iodide can result in different bandgaps. Using different amounts of lead (II) chloride can affect the crystal stability of the photoactive layer and can prevent phase segregation within the layer. The amount of lead (II) chloride added can be greater than the amount of lead (II) bromide added by weight. The amount of lead (II) chloride added can be less than the amount of lead (II) bromide added by weight. The amount of lead (II) chloride added can be the same as the amount of lead (II) bromide added by weight. The amount of lead (II) iodide soluble in a solution can be related to the amount of lead (II) bromide and lead (II) chloride in the solution. For example, adding in more lead (II) bromide and lead (II) chloride to a solution of lead (II) iodide can improve solubility of the lead (II) iodide and result in decreased particulate in the photoactive layer.

[0158] The perovskite precursor can be in a solution with one or more solvents, e.g., alternatively or in addition to the one or more recrystallization solvents. For example, leadAttorney Docket No.54741-0044WO1 (II) iodide and dimethyl sulfoxide can be used in the solution. The perovskite precursor can be in the solution of at least about 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 99, or more weight percent perovskite precursor. The perovskite precursor can be in the solution of at most about 99, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, 0.1, or less weight percent perovskite precursor. Examples of solvents include, but are not limited to, polar solvents (e.g., water, dimethyl sulfoxide, dimethylformamide, ethers, esters, acetates, acetone, etc.), non-polar solvents (e.g., hexanes, toluene, etc.), or the like, or any combination thereof. Proper mixing of the solvent as well as solvent composition can contribute to controlled solvent removal speeds and thus impact grain development as well as bulk defect formation. Tuning the interaction of the coordination strength of a solvent and the evaporation rate of a precursor solution can enable better control of the perovskite film that is formed as well as the reaction kinetics of the formation. For example, a weakly coordinating solvent that quickly evaporates can form a more disordered film, but may also result in less residual solvent being present in the film. Mixtures of solvents can improve solute solubility, decrease evaporation rates, improve performance of application methods, and the like. For example, a combination of N-Methyl-2-pyrrolidone (NMP) and dimethyl sulfoxide (DMSO) can increase solute solubility and decrease solvent evaporation rates. In this example, the properties of the NMP / DMSO mixture can decrease premature crystallization of perovskite and improve film quality. In another example, adding NMP to dimethylformamide (DMF) can increase spray width of the solution through an ultrasonic spray on apparatus, which can provide greater flexibility in the spray on parameters used.

[0159] A variety of parameters can be tuned to provide a predetermined perovskite layer. Examples of parameters include, but are not limited to, perovskite precursor application temperature, volume application rate, ultrasonic power of an ultrasonic spray-on instrument, lateral speed of precursor application (e.g., the speed of a substrate moving through an applicator), applicator height (e.g., the distance from an applicator to the substrate), environmental factors (e.g., humidity, reactive gas content, temperature, etc.), wetting surface energy, or the like, or any combination thereof. Any portion of the process 300, including the application of the perovskite precursors, can take place in a controlled environment. The controlled environment can have a relative humidity of at least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 99%, or more. The controlled environment can have a relative humidity of at most about 99%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, or less. The controlled environment can include a controlled atmosphere. The controlled atmosphereAttorney Docket No.54741-0044WO1 can include inert gasses (e.g., nitrogen, noble gases, etc.). The controlled atmosphere can have an oxygen content of at least about 1 part per million (ppm), 10 ppm, 50 ppm, 100 ppm, 500 ppm, 1,000 ppm, 5,000, ppm, 1%, 5%, 10%, 15%, 20%, or more. The controlled atmosphere can have an oxygen content of at most about 20%, 15%, 10%, 5%, 1%, 5,000 ppm, 1,000 pm, 500 ppm, 100 ppm, 50 ppm, 10 ppm, 1 ppm, or less. The controlled atmosphere can be at a temperature of at least about 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 160, 170, 180, 190, 200, or more degrees Celsius. The controlled atmosphere can be at a temperature of at most about 200, 190, 180, 170, 160, 150, 145, 140, 135, 130, 125, 120, 115, 110, 105, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, or less degrees Celsius.

[0160] The process 300 includes performing one or more processing operations to the perovskite precursor to generate a perovskite layer on the hole transport layer (350). The one or more processing operations can include annealing, light exposure (e.g., ultraviolet light exposure), agitation (e.g., vibration), functionalization (e.g., surface functionalization), electroplating, template inversion, or the like, or any combination thereof. For example, a substrate with perovskite precursors can be annealed to form a photoactive perovskite layer from the precursors. In another example, perovskite precursors can be annealed and subsequently functionalized. The annealing can be annealing under inert atmosphere (e.g., argon atmosphere, nitrogen atmosphere). The annealing can be under a reactive atmosphere (e.g., an atmosphere including a reagent (e.g., methylammonium)). The annealing can be at a temperature of at least about 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130, 135, 140, 145, 150, 160, 170, 180, 190, 200, or more degrees Celsius. The annealing can be at a temperature of at most about 200, 190, 180, 170, 160, 150, 145, 140, 135, 130, 125, 120, 115, 110, 105, 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, or less degrees Celsius. The annealing can be at a temperature range as defined by any two of the proceeding values. For example, the annealing can be at a temperature of 90 to 120 degrees Celsius. The annealing can be for a time of at least about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 75, 90, 105, 120, or more minutes. The annealing can be for a time of at most about 120, 105, 75, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0.5, or less minutes. The annealing can be for a time range as defined by any two of the proceeding values. For example, the annealing can be for a time of about 5 to about 15 minutes. There can be a number of annealing processes applied to the substrate. For example, a substrate can be annealed at a first time and temperature, and subsequently annealed again at a second timeAttorney Docket No.54741-0044WO1 and temperature. Such additional annealing processes can reduce the number of defects present in the perovskite layer and improve performance.

[0161] Operation 350 can optionally include applying one or more additional layers to the perovskite layer. The one or more additional layers can include one or more additional perovskite layers. For example, a second perovskite layer with a different bandgap can be applied to the first perovskite layer. The one or more additional layers can include one or more additional perovskite precursors. For example, iodine gas can be applied to form an iodine layer on a perovskite layer and / or a layer of a perovskite precursor. Applying the one or more additional layers can include one or more washing operations. A washing operation can include an application of a solvent to the perovskite layer. Examples of solvents include, but are not limited to, water, non-polar organic solvents (e.g., hexanes, toluene, etc.), polar organic solvents (e.g., methanol, ethanol, isopropanol, acetone, etc.), ionic solvents, or the like. The one or more additional layers can include a passivating layer. The one or more additional layers can include one or more passivating layers. A passivating layer can include a reagent configured to passivate and / or stabilize the perovskite layer. For example, an application of a solution including phenethylammonium iodide can passivate and stabilize the grains of the perovskite layer.

[0162] Operation 350 can optionally include performing one or more lithography operations on the perovskite layer. The one or more lithography operations can be one or more lithography operations as described elsewhere herein.

[0163] The process 300 includes applying an electron transport layer to the perovskite layer (360). The electron transport layer can be applied using appropriate methods as described elsewhere herein (e.g., physical vapor deposition, ultrasonic spray-on, etc.). The electron transport layer can include a material with a conduction band minimum less than that of the photoactive layer. For example, if the perovskite layer has a conduction band minimum of -3.9 eV, the electron transport layer can have a conduction band minimum of -4.2 eV. Examples of electron transport layer materials include, but are not limited to, titanium oxide (e.g., TiO2), zinc oxide, tin oxide, tungsten oxide, indium oxide, niobium oxide, iron oxide, cerium oxide, strontium titanium oxide, zinc tin oxide, barium tin oxide, cadmium selenide, indium sulfide, lead iodide, organic molecules (e.g., phenyl-C61 -butyric acid methyl ester (PCBM), poly(3- hexylthiophene-2,5-diyl) (P3HT), etc.), lithium fluoride, buckminsterfullerene (C60), or the like, or any combination thereof.Attorney Docket No.54741-0044WO1

[0164] Operation 360 can optionally include performing one or more lithography operations on the electron transport layer. The one or more lithography operations can be one or more lithography operations as described elsewhere herein.

[0165] The process 300 includes scribing P2 scribe lines through the electron transport layer and the perovskite layer (365). In some examples, the P2 scribe lines can also extend through the hole transport layer. In general, the purpose of operation 365 is to expose the first transparent conducting layer, e.g., in thin lines, so that operation 370 to follow will connect the first and second transparent conducting layers together, allowing the serial contacting of perovskite subcells. Operation 365 can be achieved by mechanical means, or via laser scribing methods using ultraviolet light, visible light, or infrared light generated from a laser (e.g., a continuous wave or pulsed laser).

[0166] The process 300 includes applying a second transparent conducting layer to the electron transport layer (370). The second transparent conducting layer can include a transparent conductive oxide (e.g., indium tin oxide (ITO), indium zinc oxide, aluminum zinc oxide, indium cadmium oxide, etc.), a transparent conductive polymer (e.g., poly(3,4- ethylenedioxythiophene) (PEDOT), poly(3,4- ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), poly(4,4-dioctyl cyclopentadithiophene), etc.), carbon nanotubes, graphene, nanowires (e.g., silver nanowires), metallic grids (e.g., grid contacts including metals), thin films (e.g., thin metal films), conductive grain boundaries, or the like, or any combination thereof. The second transparent conducting layer can have a full spectrum transparency of at least about 20%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.9%, or more. The second transparent conducting layer can have a full spectrum transparency of at most about 99.9%, 99%, 98%, 97%, 96%, 95%, 90%, 85%, 80%, 75%, 70%, 60%, 50%, 40%, 30%, 20%, or less. The second transparent conducting layer can have a full spectrum transparency in a range as defined by any two of the proceeding values. For example, the first transparent conducting layer can have a full spectrum transparency of 75% to 85%. The second transparent conducting layer can have a transparency over a spectral band of at least about 20%, 30%, 40%, 50%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, 99.9%, or more. The second transparent conducting layer can have a transparency over a spectral band of at most about 99.9%, 99%, 98%, 97%, 96%, 95%, 90%, 85%, 80%, 75%, 70%, 60%, 50%, 40%, 30%, 20%, or less. For example, the second transparent conducting layer can have a transmission of 85% or more over the wavelength range from 400 nm to 1200 nm. The second transparent conducting layer can function as a barrier to the perovskite layer for moisture, gas, dust, and the like. TheAttorney Docket No.54741-0044WO1 second transparent conducting layer can also prevent the diffusion of ions (e.g., metal ions) which may impact the performance of the perovskite layer. The second transparent conducting layer can be of the same type as the first transparent conducting layer. For example, both the first and second transparent conducting layers can be composed of indium tin oxide. The second transparent conducting layer can be of a different type as the first transparent conducting layer. The second transparent conducting layer can be deposited on the electron transport layer using appropriate methods as described elsewhere herein (e.g., physical vapor deposition, etc.).

[0167] Operation 370 can optionally include performing one or more lithography operations on the electron transport layer. The one or more lithography operations can be one or more lithography operations as described elsewhere herein.

[0168] Operation 370 can optionally include applying one or more busbars to the second transparent conducting layer. The one or more busbars can be applied as busbars (e.g., preformed busbars are applied to the second transparent conducting layer). For example, a mask can be used to form the busbars from an evaporation process. The one or more busbars can be applied as a solid film and subsequently formed into the busbars. For example, a silver film can be deposited onto the second transparent conducting layer and etched to form the busbars. In another example, a laser scribe can be used to form the busbars from a silver film. The busbars can be attached to at least about 2, 3, 4, or more terminals. The busbars can be attached to at most about 4, 3, 2, or less terminals. The terminals can be configured to form a parallel connection with one or more additional photovoltaic modules. The terminals can be configured to form a series connection with one or more additional photovoltaic modules. The terminals can be scribed (e.g., laser scribed). The terminals can be configured to enable connection of a perovskite photovoltaic device with another photovoltaic device prior to a lamination of the two photovoltaic devices. For example, a perovskite photovoltaic device can be connected via two terminals to a silicon photovoltaic device.

[0169] The process 300 includes scribing P3 scribe lines through the second transparent conducting layer, the electron transport layer, and the perovskite layer (375). In some examples, the P3 scribe lines can also extend through the hole transport layer. In general, the purpose of operation 375 is to isolate the second transparent conducting layer from two neighboring perovskite subcells. Operation 375 can be achieved by mechanical means, or via laser scribing methods using ultraviolet light, visible light, or infrared light generated from a laser (e.g., a continuous wave or pulsed laser).Attorney Docket No.54741-0044WO1

[0170] The process 300 optionally includes scribing P4 scribe lines through the second transparent conducting layer, the electron transport layer, the perovskite layer, the hole transport layer, and the first transparent conducting layer (376). The P4 scribe lines are perpendicular to the P1, P2, and P3 scribe lines. In general, the purpose of operation 376 is to segment long, serially connected perovskite subcells into shorter ones, e.g., to mitigate the effects of defects in any one perovskite subcell. Operation 376 can be achieved by mechanical means, or via laser scribing methods using ultraviolet light, visible light, or infrared light generated from a laser (e.g., a continuous wave or pulsed laser).

[0171] The process 300 is continued in different variation in FIGs.6A-6D.

[0172] FIG.6A-6B are flowcharts of example fabrication processes 301A-301D for forming different types of oxygen gettering systems on the perovskite photovoltaic.

[0173] Referring to FIG.6A which includes a flowchart of process 301A.

[0174] The process 301A includes removing material from the perovskite photovoltaic at the edges of the substrate (380A). Removing material, particularly material from the perovskite layer, avoids creating a potential ingress path that bypasses edge seals.

[0175] The process 301A includes forming an oxygen gettering system on the edges of the substrate, the perovskite photovoltaic, or both (385A). The oxygen gettering system can be deposited using appropriate methods as described elsewhere herein (e.g., physical vapor deposition, chemical vapor deposition, atomic layer deposition, ultrasonic spray-on, thermal spray-on, blade-coating, roll-coating, slot-die coating, etc.). The oxygen gettering system can be formed by depositing a sacrificial material including an oxygen getter to the substrate and laterally about the perovskite photovoltaic. In some cases, the oxygen gettering system is formed by first forming a confinement well on the substrate. For example, an inner portion of the confinement well can be formed laterally about the perovskite photovoltaic, and an outer portion of the confinement well can be formed laterally about the inner portion. The sacrificial material can then be deposited between the inner and outer portions of the confinement well to confine the sacrificial material therein. In some examples, the oxygen getter generates water vapor when combining with oxygen. For example, the oxygen getter can be composed of the same perovskite as the perovskite layer. In some of these cases, the oxygen gettering system can be formed by further depositing an absorber material including a desiccant on the substrate and laterally about the perovskite photovoltaic, where the absorber material is positioned between the sacrificial material and the perovskite photovoltaic. In other cases, the oxygen gettering system can be formed by first applying a layer of theAttorney Docket No.54741-0044WO1 absorber material to the perovskite photovoltaic (e.g., to the electrically insulating layer) and subsequently applying a layer of the sacrificial material to the layer of the absorber material.

[0176] The process 301A includes applying an encapsulant to the perovskite photovoltaic (390A). For example, the encapsulant can be applied on the edge of the full stack of layers to help prevent moisture and oxygen diffusion into the stack. The encapsulant can also be applied over the oxygen gettering system and onto the substrate. The encapsulant can be substantially transparent. The encapsulant can be configured to reduce or substantially eliminate an exposure of the perovskite layer to one or more reactive species. Examples of reactive species include, but are not limited to, oxygen, water, and polar molecules (e.g., polar volatile organic compounds, acids, etc.). Examples of encapsulants include, but are not limited to, PDMS, HelioSeal™, silicon glue, butyl-based sealants, or the like. In some cases, the encapsulant can be loaded with a desiccant, an oxygen getter, or both to further reduce exposure of the perovskite layer to water and / or oxygen vapor. The encapsulant can be placed such that the encapsulant ends at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, or more millimeters from the edge. The encapsulant can be placed such that the encapsulant ends at most about 25, 24, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, or fewer millimeters from the edge.

[0177] Referring to FIG.6B which includes a flowchart of process 301B.

[0178] The process 301B includes applying an electrically insulating layer to the second transparent conducting layer (380B), where the electrically insulating layer provides a barrier to perovskite precursor solvent and water. In some examples, the electrically insulating layer can include dielectrics such as silicon dioxide, titanium dioxide, aluminum oxide, silicon nitride, or the like, or any combination thereof. The electrically insulating layer may be applied at temperatures of about 150oC, 140oC, 130oC, 120oC, 110oC, 100oC, or less. Applying the electrically insulating layer at such temperatures can mitigate damage to the underlying perovskite layer. In these cases, the electrically insulating layer can be deposited on the second transparent conducting layer using appropriate methods as described elsewhere herein (e.g., physical vapor deposition, chemical vapor deposition, atomic layer deposition, ultrasonic spray-on, thermal spray-on, etc.). In some examples, the electrically insulating layer can include a polymer (e.g., parylene) or a photopolymer. In these cases, the electrically insulating layer can be deposited on the second transparent conducting layer using appropriate methods as described elsewhere herein (e.g., blade-coating, roll-coating, slot-die coating, etc.) and may subsequently be cured, e.g., via heat exposure for a thermoset polymer or ultraviolet exposure for a photopolymer.Attorney Docket No.54741-0044WO1

[0179] The process 301B includes applying a second perovskite precursor to the electrically insulating layer (340*). Operation 340* can be performed as described above for operation 340.

[0180] The process 300 includes performing one or more processing operations to the second perovskite precursor to generate a second perovskite layer on the electrically insulating layer (350*). Operation 350* can be performed as described above for operation 350. Here, the second perovskite layer serves as a layer of a sacrificial material. In some examples, the first and second perovskite layers are composed of the same perovskite.

[0181] The process 301B includes applying an encapsulant to the second perovskite layer (390B). Operation 390B can be performed as described above for operation 390A.

[0182] Referring to FIG.6C which includes a flowchart of process 301C.

[0183] The process 301C includes applying an electrically insulating layer to the second transparent conducting layer (380C), where the electrically insulating layer provides a barrier to water. Operation 380C can be performed as described above for operation 380B.

[0184] The process 301C includes applying an encapsulant preloaded with perovskite particles to the electrically insulating layer (390C). Operation 390C can be performed as described above for operation 390A.

[0185] Referring to FIG.6D which includes a flowchart of process 301D.

[0186] The process 301D includes applying an electrically insulating layer to the second transparent conducting layer (380D), where the electrically insulating layer provides a barrier to cesium-, methylammonium-, or formamidinium-halides. Operation 380D can be performed as described above for operation 380B.

[0187] The process 301C includes applying an encapsulant preloaded with perovskite particles to the electrically insulating layer (390D). Operation 390D can be performed as described above for operation 390A.

[0188] FIG.7 is a flowchart of an example fabrication process 400 for forming a tandem solar module.

[0189] The process 400 includes providing a silicon solar panel (410). The silicon solar panel can be a silicon solar panel as described elsewhere herein. For example, the silicon solar panel can be a front contact solar panel, an integrated back contact solar panel, a shingled solar panel, or the like. The silicon solar panel can have at least about 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 72, 75, 80, 85, 90, 95, 96, or more solar cells. The silicon solar panel can have at most about 96, 95, 90, 85, 80, 75, 72, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 10, or less silicon solar cells. In some embodiments, the silicon solar panel hasAttorney Docket No.54741-0044WO1 60 six-inch solar cells arranged in a 6-by-10 grid. The silicon solar cells can be connected in series. The silicon solar cells can be connected in parallel. The silicon solar cells can each have an open-circuit voltage of 0.7 Volts, for a total open-circuit voltage of approximately 42 Volts.

[0190] The process 400 includes fabricating a perovskite photovoltaic (or perovskite-on- glass) on a top glass sheet of the silicon solar panel (420) The perovskite photovoltaic can be fabricated using the process 300 of FIG.5. The perovskite photovoltaic can have at least about 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more layers. The perovskite photovoltaic can have at most about 10, 9, 8, 7, 6, 5, 4, 3, 2, or less layers.

[0191] The process 400 includes laser scribing the perovskite photovoltaic to generate multiple perovskite solar cells (430). The perovskite solar cells can be at least about 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 99, or more perovskite solar cells. The perovskite solar cells can be at most about 99, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, 20, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or less perovskite solar cells. The perovskite solar cells can be connected in series. The perovskite solar cells can be connected in parallel. The laser scribing can separate the perovskite photovoltaic into a number of segments. The segments can be formed into the perovskite solar cells. For example, terminals or contacts can be applied to the segments to extract charge from the segments.

[0192] The laser scribing can be configured to generate the perovskite solar cells which, when connected together, have a same or substantially same voltage output as the silicon solar panel. The voltage output of the perovskite photovoltaic per unit area can be known, and the perovskite photovoltaic can be scribed to form the perovskite solar cells of a size that provide a predetermined voltage. For example, the perovskite photovoltaic can be scribed to form 5 perovskite sub-modules each including 40 perovskite solar cells to match a silicon solar module that has a same voltage output as the 40 perovskite solar cells. In this example, the 5 perovskite sub-modules can be connected in parallel to increase the current produced by the perovskite photovoltaic while maintaining the voltage match with the silicon solar module.

[0193] In some examples, the process 400 can include applying a number of contacts to the perovskite solar cells to electrically couple the perovskite solar cells. The contacts can be applied using one or more processes as described elsewhere herein. For example, the contacts can be evaporated onto the perovskite solar cells. In another example, the contacts can be lithographically applied to the perovskite solar cells.Attorney Docket No.54741-0044WO1

[0194] The process 400 includes connecting the silicon solar cells of the silicon solar panel to the perovskite solar cells to form a tandem module (440). The silicon solar cells and the perovskite solar cells can be in a voltage matched configuration. The voltage matched configuration can be as described elsewhere herein. For example, the silicon solar cells can have the same voltage as the perovskite solar cells. The perovskite solar cells can be connected to one another in parallel. The perovskite solar cells can be connected to one another in series. The perovskite solar cells can be connected such that there are a number of modules in the perovskite photovoltaic. For example, rows of the perovskite solar cells can be each connected in series and the connected rows can be connected in parallel. The silicon solar panel and the perovskite solar panel can be connected as described elsewhere herein. For example, the perovskite solar cells can be connected via copper (or another metal, charge collection tape, etc.) terminals to the same junction box as the silicon solar cells.

[0195] The process 400 includes encapsulating the tandem solar module (450). The encapsulating can include applying an encapsulant to the perovskite photovoltaic as described with reference to operation 395 of FIG.5. For example, the encapsulating can include applying a thermal-plastic polyolefin to the perovskite photovoltaic, e.g., via evaporation. In another example, the encapsulant can be spread as a viscous solution onto the perovskite photovoltaic. The encapsulating can also include applying an edge seal to the tandem solar module. The edge seal can be as described elsewhere herein. For example, the edge seal can be composed of HelioSeal™ or polyisobutylene. The edge seal can have a width of about 20 mm or more.

[0196] The process 400 includes adhering a metallized tape to an edge of the tandem solar module (460). The metallized tape can include a metal layer, a polymer layer, and an adhesive layer as described elsewhere herein. The adhering can include applying the metallized tape along a lateral surface of the tandem solar module, including a lateral surface of an edge seal, the top glass sheet, and the silicon solar panel. The metallized tape can be adhered to the top and bottom surfaces of the tandem solar module. For example, the metallized tape can extend about 20 mm or more from the edge of tandem solar module onto the top and bottom surfaces.

[0197] The silicon solar cells and the perovskite solar cells can be electronically coupled to a same junction box. Such coupling to the same junction box can allow for simple integration of the perovskite photovoltaic into existing silicon solar modules. Such coupling can also provide for simple installation of the tandem solar module, as there can be a single output from the tandem solar module instead of multiple outputs. Examples of differentAttorney Docket No.54741-0044WO1 electrical network connections for different types of silicon-perovskite hybrid solar modules is described in Int’l. Appl. No. PCT / US2021 / 051465.

[0198] While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. It is not intended that the invention be limited by the specific examples provided within the specification. While the invention has been described with reference to the aforementioned specification, the descriptions and illustrations of the embodiments herein are not meant to be construed in a limiting sense. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. Furthermore, it shall be understood that all aspects of the invention are not limited to the specific depictions, configurations or relative proportions set forth herein which depend upon a variety of conditions and variables. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is therefore contemplated that the invention shall also cover any such alternatives, modifications, variations, or equivalents. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.

[0199] Whenever the term “at least,” “greater than,” or “greater than or equal to” precedes the first numerical value in a series of two or more numerical values, the term “at least,” “greater than” or “greater than or equal to” applies to each of the numerical values in that series of numerical values. For example, greater than or equal to 1, 2, or 3 is equivalent to greater than or equal to 1, greater than or equal to 2, or greater than or equal to 3.

[0200] Whenever the term “no more than,” “less than,” or “less than or equal to” precedes the first numerical value in a series of two or more numerical values, the term “no more than,” “less than,” or “less than or equal to” applies to each of the numerical values in that series of numerical values. For example, less than or equal to 3, 2, or 1 is equivalent to less than or equal to 3, less than or equal to 2, or less than or equal to 1.

[0201] The term “solar cell,” as used herein, generally refers to a device that uses the photovoltaic effect to generate electricity from light.

[0202] The term “tandem solar cell,” as used herein, refers to a solar cell with two solar cells that are stacked on top of one another.

[0203] The term “4-terminal,” as used herein, refers to a tandem solar cell in which the top and bottom solar cells each have two accessible terminals.Attorney Docket No.54741-0044WO1

[0204] The term “perovskite,” as used herein, generally refers to a material with a crystal structure similar to calcium titanium oxide and one that is suitable for use in perovskite solar cells. The general chemical forum for a perovskite material is ABX3. Examples of perovskite materials include methylammonium lead trihalide (i.e., CH3NH3PbX3, where X is a halogen ion such as iodide, bromide, or chloride) and formamidinium lead trihalide (i.e., H2NCHNH2PbX3, where X is a halogen ion such as iodide, bromide, or chloride).

[0205] The term “monocrystalline silicon,” as used herein, generally refers to silicon with a crystal structure that is homogenous throughout the material. The orientation, lattice parameters, and electronic properties of monocrystalline silicon can be constant throughout the material. Monocrystalline silicon can be doped with phosphorus or boron, for example, to make the silicon n-type or p-type respectively.

[0206] The term “polycrystalline silicon,” as used herein, generally refers to silicon with an irregular grain structure.

[0207] The terms “passivated emitter rear contact (PERC) solar cell,” as used herein, generally refer to a solar cell with an extra dielectric layer on the rear-side of the solar cell. This dielectric layer can act to reflect unabsorbed light back to the solar cell for a second absorption attempt and can additionally passivate the rear surface of the solar cell, increasing the solar cell’s efficiency.

[0208] The terms “heterojunction with intrinsic thin layer solar cell (HIT) solar cell,” as used herein, generally refer to a solar cell that is composed of a monocrystalline silicon wafer surrounded by ultra-thin amorphous silicon layers. One amorphous silicon layer can be n- doped, while the other can be p-doped.

[0209] The term “an interdigitated back contact cell (IBC),” as used herein, generally refers to a solar cell including two or more electrical contacts disposed on the back side of the solar cell (e.g., on the side opposite the incident light). The two or more electrical contacts can be disposed adjacent to alternatingly n- and p-doped regions of the solar cell. An IBC can include a high-quality absorber material configured to permit carrier migration over a long distance.

[0210] The terms “bandgap” and “band gap,” as used herein, generally refer to the energy difference between the top of the valence band and the bottom of the conduction band in a material.

[0211] The term “electron transport layer” (“ETL”), as used herein, generally refers to a layer of material that facilitates electron transport and inhibits hole transport in a solar cell. Electrons are majority carriers in an ETL, while holes are minority carriers. An ETL can beAttorney Docket No.54741-0044WO1 composed of one or more n-type layers. The one or more n-type layers can include an n-type exciton blocking layer. The n-type exciton blocking layer can have a wider bandgap than the photoactive layer of the solar cell (e.g., a perovskite layer) but a conduction band that is closely matched to the conduction band of the photoactive layer. This allows electrons to easily pass from the photoactive layer to the ETL.

[0212] The n-type layer can be a metal oxide, a metal sulfide, a metal selenide, a metal telluride, amorphous silicon, an n-type group IV semiconductor (e.g., germanium), an n-type group III-V semiconductor (e.g., gallium arsenide), an n-type group II- VI semiconductor (e.g., cadmium selenide), an n-type group I- VII semiconductor (e.g., cuprous chloride), an n- type group IV-VI semiconductor (e.g., lead selenide), an n-type group V-VI semiconductor (e.g., bismuth telluride), or an n-type group II-V semiconductor (e.g., cadmium arsenide), any of which can be doped (e.g., with phosphorus, arsenic, or antimony) or undoped. The metal oxide can be an oxide of titanium, tin, zinc, niobium, tantalum, tungsten, indium, gallium, neodymium, palladium, cadmium, or an oxide of a mixture of two or more of such metals. The metal sulfide can be a sulfide of cadmium, tin, copper, zinc or a sulfide of a mixture of two or more of such metals. The metal selenide can be a selenide of cadmium, zinc, indium, gallium or a selenide of a mixture of two or more of such metals. The metal telluride can be a telluride of cadmium, zinc, cadmium or tin, or a telluride of a mixture of two or more of said metals. Alternatively, other n-type materials can be employed, including organic and polymeric electron transporting materials, and electrolytes. Suitable examples include, but are not limited to, a fullerene or a fullerene derivative (e.g., phenyl-C61-butyric acid methyl ester, C60, etc.) or an organic electron transporting material including perylene or a derivative thereof.

[0213] The term “hole transport layer” (“HTL”), as used herein, generally refers to a layer of material that facilitates hole transport and inhibits electron transport in a solar cell. Holes are majority carriers in an HTL, while electrons are minority carriers. An HTL can be composed of one or more p-type layers. The one or more p-type layers can include a p-type exciton blocking layer. The p-type exciton blocking layer generally has a valence band that is closely matched to the valence band of the photoactive layer (e.g., a perovskite layer) of the solar cell. This allows holes to easily pass from the photoactive layer to the HTL.

[0214] The p-type layer can be made of a molecular hole transporter, a polymeric hole transporter, or a copolymer hole transporter. For example, the p-type layer can be one or more of the following: nickel oxide, thiophenyl, phenelenyl, dithiazolyl, benzothiazolyl, diketopyrrolopyrrolyl, ethoxydithiophenyl, amino, triphenyl amino, carbozolyl, ethyleneAttorney Docket No.54741-0044WO1 dioxythiophenyl, dioxythiophenyl, or fluorenyl. Additionally or alternatively, the p-type layer can include spiro-OMeTAD (2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'- spirobifluorene)), P3HT (poly(3-hexylthiophene)), PCPDTBT (Poly[2,l,3-benzothiadiazole- 4,7- diyl[4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,l-b:3,4-b']dithiophene-2,6-diyl]]), PVK (poly(N- vinylcarbazole)), poly(3 -hexylthiophene), poly[N,N-diphenyl-4- methoxyphenylamine-4',4"- diyl], sexithiophene, 9,10-bis(phenylethynyl)anthracene, 5,12- bis(phenylethynyl)naphthacene, diindenoperylene, 9,10-diphenylanthracene, PEDOT-TMA, PEDOT:PSS, perfluoropentacene, perylene, poly(p-phenylene oxide), poly(p-phenylene sulfide), quinacridone, rubrene, 4- (dimethylamino)benzaldehyde diphenylhydrazone, 4- (dibenzylamino) benzaldehyde- N,Ndiphenylhydrazone, or phthalocyanines.

[0215] The term “desiccant”, as used herein, generally refers to a material or substance that absorbs moisture from its surroundings. Examples of desiccants include, but are not limited to, activated alumina, aerogel, benzophenone, bentonite clay, calcium chloride, calcium oxide, calcium sulfate, cobalt(II) chloride copper(II) sulfate, lithium chloride, lithium bromide, magnesium chloride hexahydrate, magnesium sulfate, magnesium perchlorate, molecular sieve, phosphorus pentoxide, potassium carbonate, potassium hydroxide, silica gel, sodium, sodium chlorate, sodium chloride, sodium hydroxide, sodium sulfate, sucrose, sulfuric acid, triethylene glycol, zeolite, or the like, or any combination thereof.

[0216] The term “oxygen getter”, as used herein, generally refers to a material or substance that combines with oxygen in its surroundings either chemically or by absorption. An oxygen getter may also be referred to as an “oxygen scavenger” or an “oxygen absorber”. Examples of oxygen getters include, but are not limited to, quantum dots, iron, zirconium, titanium, copper, aluminum, magnesium, barium, sodium sulfite, hydrazine, zeolite, catechol, hydroquinone, ascorbic acid, activated carbon, or the like, or any combination thereof. The various perovskite compositions disclosed herein (e.g., implemented as a perovskite layer in a perovskite photovoltaic) are additional examples of oxygen getters that can rapidly uptake oxygen. In some cases, an oxygen getter can be provided in a powdered form. Decreasing an average particle size (e.g., an average particle diameter) of a powder of an oxygen getter generally increases the surface area per unit volume, thereby increasing the capacity of the oxygen getter for oxygen absorption. This can scale as the inverse of the nominal particle size down to the nanometer scale. For example, a powder of an oxygen getter can have an average particle size of at most about 20 μm, 15 μm, 10 μm, 5 μm, 1 μm, 900 nm, 800 nm, 700 nm, 600 nm, 500 nm, 250 nm, 100 nm, 50 nm, 25 nm, 10 nm, or less.Attorney Docket No.54741-0044WO1

[0217] In general, the methods and devices of the present disclosure may be used with any solar cells with a perovskite layer. For example, tandem solar cells can include a perovskite solar cell in combination with any other type of solar cell, e.g., a silicon solar cell or a cadmium telluride (CdTe) solar cell. In another example, a tandem solar cell can include a dye sensitized solar cell and a perovskite solar cell. In a further example, a solar module can be composed only of perovskite solar cells.

[0218] A number of embodiments are described. Other embodiments are in the following claims, accompanied by further description in Appendix A.

Claims

Attorney Docket No.54741-0044WO1 WHAT IS CLAIMED IS:

1. A perovskite solar cell, comprising: a first transparent conductive oxide layer; a hole transport layer disposed on the first transparent conductive oxide layer; a photoactive, perovskite layer disposed on the hole transport layer; an electron transport layer disposed on the perovskite layer; a second transparent conductive oxide layer disposed on the electron transport layer; an electrically insulating layer disposed on the second transparent conductive oxide layer; and one or more sets of P1, P2, and P3 scribe lines segmenting the perovskite solar cell into a plurality of perovskite subcells, wherein each set of P1, P2, and P3 scribe lines comprises: a P1 scribe line extending through each of the hole transport and first transparent conductive oxide layers, the perovskite layer filling the P1 scribe line; a P2 scribe line extending through each of the electron transport, perovskite, and hole transport layers, the second transparent conductive oxide layer filling the P2 scribe line; and a P3 scribe line extending through each of the second transparent conductive oxide, electron transport, perovskite, and hole transport layers, the electrically insulating layer filling the P3 scribe line.

2. The perovskite solar cell of claim 1, wherein the perovskite layer has a thickness of 1,000 nanometers (nm) or less.

3. The perovskite solar cell of claim 2, wherein the perovskite layer has thickness in a range from 400 nm to 600 nm.

4. The perovskite solar cell of any preceding claim, wherein: the perovskite layer is composed of a perovskite selected from the group represented by MAn1FAn2Csn3PbX3, MA is methylammonium, FA is formamidinium, Cs is Cesium, Pb is lead, and X is a halogen, and n1, n2, and n3 are each independently greater than 0 and less than 1.Attorney Docket No.54741-0044WO1 5. The perovskite solar cell of claim 3, wherein n1 + n2 + n3 = 1.

6. The perovskite solar cell of any of claims 1-2, wherein the perovskite layer is composed of methylammonium lead trihalide (CH3NH3PbX3) or a formamidinium lead trihalide (H2NCHNH2PbX3), and X is a halogen.

7. The perovskite solar cell of any of claims 3-5, wherein the halogen is selected from the group consisting of: fluorine, chlorine, bromine, and iodine.

8. The perovskite solar cell of claim 7, wherein the halogen is iodine.

9. The perovskite solar cell of any preceding claim, wherein the hole transport layer is composed of one or more nickel oxides.

10. The perovskite solar cell of any preceding claim, wherein the electron transport layer is composed of phenyl-C61-butyric acid methyl ester or buckminsterfullerene.

11. The perovskite solar cell of any preceding claim, wherein the first and second transparent conductive oxide layers are each composed of indium tin oxide.

12. The perovskite solar cell of any preceding claim, wherein the perovskite layer is doped with one or more of: bromine, cesium iodide, or methylammonium chloride.

13. The perovskite solar cell of any preceding claim, wherein the electrically insulating layer has thickness of 500 nm or less.

14. The perovskite solar cell of claim 13, wherein the electrically insulating layer has a thickness of 100 nm or less.

15. The perovskite solar cell of any preceding claim, wherein the electrically insulating layer is composed of silicon dioxide, titanium dioxide, silicon nitride, aluminum oxide, parylene, or a photopolymer.

16. A solar module, comprising:Attorney Docket No.54741-0044WO1 a substrate having: (i) a first surface, and (ii) a second, opposite surface; a superstrate arranged parallel to the substrate, the superstrate having: (i) a first surface facing the first surface of the substrate, and (ii) a second, opposite surface; an edge seal disposed between the first surfaces of the substrate and superstrate, wherein each of the substrate, superstrate, and edge seal has a respective lateral surface aligned with one another; a perovskite photovoltaic disposed on the first surface of the substrate, the edge seal arranged laterally about the perovskite photovoltaic; and an oxygen-barrier tape adhered to the lateral surfaces of the substrate, superstate, and edge seal, the oxygen-barrier tape extending onto the second surfaces of the substrate and superstrate.

17. The solar module of claim 16, wherein the edge seal has a width of 5 millimeters (mm) or more, and the oxygen-barrier tape extends 5 mm or more onto the second surfaces of the substrate and superstrate.

18. The solar module of any of claims 16-17, wherein the oxygen-barrier tape comprises: a metal layer and an adhesive layer; or an ethylene-vinyl alcohol layer and the adhesive layer.

19. The solar module of claim 18, wherein the metal layer is composed of aluminum, gold, silver, copper, nickel, chromium, steel, or zinc.

20. The solar module of any of claims 18-19, wherein the adhesive layer is composed of an acrylic adhesive.

21. The solar module of claim 20, wherein the adhesive layer is loaded with a desiccant, an oxygen getter, or both.

22. The solar module of any of claims 18-21, wherein the oxygen-barrier tape further comprises a polymer layer disposed between the metal and adhesive layers.Attorney Docket No.54741-0044WO1 23. The solar module of claim 22, wherein the polymer layer is composed of polyisobutylene, polyethylene, polypropylene, polystyrene, polyethylene terephthalate, polyethersulfone, polyethylene naphthalate, or polyimide.

24. The solar module of any of claims 22-23, wherein the polymer layer is loaded with a desiccant, an oxygen getter, or both.

25. The solar module of any of claims 16-24, wherein the edge seal is composed of polyisobutylene.

26. The solar module of any of claims 16-25, wherein the edge seal is loaded with a desiccant, an oxygen getter, or both.

27. The solar module of any of claims 16-26, further comprising a sacrificial material comprising an oxygen getter disposed on the first surface of the substrate, the sacrificial material arranged laterally about the perovskite photovoltaic.

28. The solar module of claim 27, further comprising a confinement well disposed on the first surface of the substrate, the confinement well comprising: a first portion arranged laterally about the perovskite photovoltaic; and a second portion arranged laterally about the first portion, wherein the sacrificial material is positioned between the first and second portions of the confinement well.

29. The solar module of claim 28, wherein the confinement well is composed of a polymer.

30. The solar module of claim 27, further comprising an absorber material comprising a desiccant disposed on the first surface of the substrate, the absorber material arranged laterally about the perovskite photovoltaic.

31. The solar module of claim 30, wherein the oxygen getter generates water when combining with oxygen, and the absorber material is positioned between the sacrificial material and the perovskite photovoltaic.Attorney Docket No.54741-0044WO1 32. The solar module of claim 31, wherein the sacrificial material is in contact with the edge seal and the absorber material.

33. The solar module of any of claims 30-32, wherein the sacrificial and absorber materials are further disposed on the first surface of the superstrate.

34. The solar module of any of claims 16-26, further comprising: a layer of an absorber material disposed on the perovskite photovoltaic, the absorber material comprising a desiccant; and a layer of a sacrificial material disposed on the layer of the absorber material, the sacrificial material comprising an oxygen getter that generates water when combining with oxygen.

35. The solar module of claim 34, wherein the layer of the absorber material is further disposed on the first surface of the substrate.

36. The solar module of claim 35, wherein the layers of the sacrificial and absorber materials are in contact with the edge seal.

37. The solar module of any of claims 27-36, wherein the sacrificial material is composed of the oxygen getter.

38. The solar module of claim 37, wherein the sacrificial material is a porous monolith of the oxygen getter.

39. The solar module of any of claims 27-36, wherein the sacrificial material is loaded with the oxygen getter.

40. The solar module of claim 39, wherein the sacrificial material is composed of a polymer having the oxygen getter suspended therein.

41. The solar module of claim 39, wherein the sacrificial material is composed of a gel or liquid solution having the oxygen getter suspended therein.Attorney Docket No.54741-0044WO1 42. The solar module of any of claims 27-41, wherein the oxygen getter is in a powdered form having a nominal particle size of 20 micrometers or less.

43. The solar module of any of claims 27-42, wherein the oxygen getter is selected from the group consisting of: quantum dots, iron, zirconium, titanium, copper, aluminum, magnesium, barium, sodium sulfite, hydrazine, zeolite, catechol, hydroquinone, ascorbic acid, or activated carbon.

44. The solar module of any of claims 27-42, wherein: the oxygen getter is a perovskite selected from the group represented by MAn1FAn2Csn3PbX3, MA is methylammonium, FA is formamidinium, Cs is Cesium, Pb is lead, and X is a halogen, and n1, n2, and n3 are each independently greater than 0 and less than 1.

45. The solar module of any of claims 16-44, wherein the perovskite photovoltaic comprises one or more perovskite solar cells.

46. The solar module of claim 45, wherein each perovskite solar cell is configured according to the perovskite solar cell of any of claims 1-15.

47. The solar module of any of claims 16-46, being a tandem solar module comprising: a first encapsulant disposed on the perovskite photovoltaic; a silicon photovoltaic disposed on the first encapsulant; and a second encapsulant disposed between the silicon photovoltaic and the first surface of the superstrate, wherein the edge seal is arranged laterally about the perovskite photovoltaic, silicon photovoltaic, and first and second encapsulants.

48. The solar module of claim 47, wherein the substrate is glass, and the superstate is glass or a back sheet.Attorney Docket No.54741-0044WO1 49. The solar module of any of claims 47-48, wherein the first encapsulant is loaded with a desiccant, an oxygen getter, or both.

50. The solar module of any of claims 16-49, having a T80 time of 12 years or more.

51. A method, comprising: providing a substrate supporting a first transparent conductive oxide layer and a hole transport layer disposed on the first transparent conductive oxide layer; applying a perovskite precursor to the hole transport layer; annealing the perovskite precursor to form a photoactive, perovskite layer on the hole transport layer; applying an electron transport layer to the perovskite layer; applying a second transparent conductive oxide layer to the electron transport layer; and applying an electrically insulating layer to the second transparent conductive oxide layer to form a perovskite photovoltaic; and laser scribing the perovskite photovoltaic to generate a plurality of perovskite solar cells.

52. The method of any of claim 51, wherein the perovskite precursor comprises a metal halide and organohalides selected from the group consisting of: formamidinium chloride, formamidinium bromide, formamidinium iodide, methylammonium chloride, methylammonium bromide, methylammonium iodide, and butylammonium halides.

53. The method of any of claims 51-52, wherein the perovskite precursor comprises one or more additives selected from the group consisting of: bromine, cesium iodide, and methylammonium chloride.

54. The method of any of claims 51-53, wherein providing the substrate supporting the transparent conductive oxide layer and the hole transport layer disposed on the transparent conductive oxide layer comprises: providing the substrate; applying the transparent conductive oxide layer to the substrate; and applying the hole transport layer to the transparent conductive oxide layer.Attorney Docket No.54741-0044WO1 55. The method of any of claims 51-54, wherein: each perovskite solar cell is segmented into a plurality of perovskite subcells by sets of P1, P2, and P3 scribe lines, and each set of P1, P2, and P3 scribe lines comprises: a P1 scribe line extending through each of the hole transport and first transparent conductive oxide layers, the perovskite layer filling the P1 scribe line; a P2 scribe line extending through each of the electron transport, perovskite, and hole transport layers, the second transparent conductive oxide layer filling the P2 scribe line; and a P3 scribe line extending through each of the second transparent conductive oxide, electron transport, perovskite, and hole transport layers, the electrically insulating layer filling the P3 scribe line.

56. The method of claim 55, further comprising: prior to applying the perovskite precursor to the hole transport layer: laser scribing the hole transport layer to generate the P1 scribe line of each set of P1, P2, and P3 scribe lines; prior to applying the electron transport layer to the perovskite layer: laser scribing the electron transport layer to generate the P2 scribe line of each set of P1, P2, and P3 scribe lines; and prior to applying the electrically insulating layer to the second transparent conductive oxide layer: laser scribing the second transparent conductive oxide layer to generate the P3 scribe line of each set of P1, P2, and P3 scribe lines.

57. The method of any of claims 51-56, further comprising forming an oxygen gettering system on the substrate, perovskite photovoltaic, or both.

58. The method of claim 57, wherein forming the oxygen gettering system on the substrate, perovskite photovoltaic, or both comprises: depositing a sacrificial material comprising an oxygen getter on the substrate and laterally about the perovskite photovoltaic.Attorney Docket No.54741-0044WO1 59. The method of claim 58, wherein: the oxygen getter generates water when combining with oxygen, and forming the oxygen gettering system on the substrate, perovskite photovoltaic, or both further comprises: depositing an absorber material comprising a desiccant on the substrate and laterally about the perovskite photovoltaic.

60. The method of claim 59, wherein forming the oxygen gettering system on the substrate, perovskite photovoltaic, or both comprises: forming a confinement well on the substrate, comprising: deposing a first portion of the confinement well on the substrate and laterally about the perovskite photovoltaic; and depositing a second portion of the confinement well on the substrate and laterally about the first portion; and depositing a sacrificial material comprising an oxygen getter between the first and second portions of the confinement well.

61. The method of claim 60, wherein forming the oxygen gettering system on the substrate, perovskite photovoltaic, or both comprises: depositing a layer of an absorber material on the perovskite photovoltaic, the sacrificial material comprising a desiccant; and depositing a layer of a sacrificial material on the layer of the absorber material, the sacrificial material comprising an oxygen getter that generates water when combining with oxygen.

62. The method of any of claims 51-61, wherein the substrate is a top glass sheet of a silicon solar panel, and the method further comprises: providing the silicon solar panel; connecting the plurality of perovskite solar cells to a plurality of silicon solar cells of the silicon solar panel to form a tandem solar module; encapsulating the tandem solar module; and adhering an oxygen-barrier tape to an edge of the tandem solar module.

63. The method of claim 62, wherein encapsulating the tandem solar module comprises:Attorney Docket No.54741-0044WO1 applying an encapsulant to the plurality of perovskite solar cells; and applying an edge seal to the tandem solar module.

64. The method of claim 63, wherein adhering the oxygen-barrier tape to the edge of the tandem solar module comprises: adhering the oxygen-barrier tape to a lateral surface of tandem solar module; and adhering the oxygen-barrier tape to a top and bottom surface of the tandem solar module.

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