Patent Description:
Perovskite containing PV devices have been previously described. For example, <CIT> describes an optoelectronic device having a layered construction, specifically comprising a base layer, a first conductive layer on the base layer, a photoactive layer on the first conductive layer and a second conductive layer on the photoactive layer, the conductive layers being in electrical contact with the photoactive layer, wherein the photoactive layer may be a perovskite. <CIT> describes a perovskite solar cell module, and more particularly, a perovskite solar cell module in which solar cells include a material having a perovskite structure as an absorbing layer. <CIT> also describes an optoelectronic device comprising a porous dielectric scaffold material and a semiconductor in contact with the scaffold material, wherein the semiconductor may be a perovskite.

Despite this progress in cell efficiency, most researches have focused on lab-scale, e.g. small-area devices (<<NUM><NUM>), fabricated by spin coating. Thus, there remains significant need for the development of practical manufacturing methods for the full-scale production of large-area solar modules that integrate multiple sub-cells. There exists a gap between the lab-scale small-area devices and the large-area solar modules, as the spin coating process is not designed for uniform coating over large size substrates. Developing scalable deposition processes for scaling up the PSCs are essential for their practical applications and commercial adaption.

Disclosed herein but not according to the claimed invention is a perovskite-containing solar cell module that includes a glass substrate; a first cell; and a second cell, where each cell includes, in order, a first contact layer that includes fluorine-doped tin oxide, positioned on the substrate, and having an outside surface and a first thickness; an electron transfer layer that includes TiO<NUM> and having a second thickness between <NUM> and <NUM>; an active layer that includes the perovskite and having a third thickness; a hole transfer layer that includes spiro-OMeTAD and having a fourth thickness; and a second contact layer that includes copper and having a fifth thickness. In addition, the first cell and the second cell are electrically connected by a first gap filled with the copper, and the first gap passes through the third thickness, the fourth thickness, and substantially through the second thickness to terminate at the outside surface.

An aspect of the present disclosure is a perovskite-containing solar cell module that includes a substrate having a first surface; a first cell; and a second cell, where each cell includes, in order, a first contact layer that includes a first material, positioned on the substrate, and having a second surface and a first thickness; an electron transfer layer (ETL) that includes a second material and having a second thickness of <NUM> - <NUM>; an active layer that includes the perovskite and having a third thickness; a hole transfer layer (HTL) that includes a third material and having a fourth thickness; and a second contact layer that includes a fourth material and having a fifth thickness. In addition, the first cell and the second cell are electrically connected by a first gap filled with the fourth material, and the first gap passes through the third thickness, the fourth thickness, and substantially through the second thickness to terminate at the second surface.

In some embodiments of the present disclosure, the module may further include a second gap filled with the second material, where the second gap passes substantially through the first thickness to terminate at the first surface, and the second gap separates the first contact of the first cell from the first contact of the second cell. In some embodiments of the present disclosure, the module may further include a third gap, where the third gap passes through fourth thickness, the third thickness, and substantially through the second thickness to terminate at the second surface, and the third gap separates the second contact of the first cell from the second contact of the second cell. In some embodiments of the present disclosure, the module may further include an insulating layer that includes a fifth material and positioned on the second contact layer, where the second contact layer is positioned between the insulating layer and the HTL, the insulating layer is not electrically conductive, and the fifth material fills the third gap.

In some embodiments of the present disclosure, the perovskite may be defined by ABX<NUM>, where A is a first cation, B is a second cation, and X is an anion. In some embodiments of the present disclosure, the perovskite may include at least one of MAPbI<NUM> and/or MAxFA<NUM>-xPbI<NUM>, wherein x is between zero and one, inclusively. In some embodiments of the present disclosure, the first material may include at least one of a metal nanowire, a carbon nanotube, a transparent conducting oxide, graphene, and/or PEDOT:PSS. In some embodiments of the present disclosure, the second material may include at least one of TiO<NUM>, ZnO, SnO<NUM>, BaSnO<NUM>, and/or SrTiO<NUM>. In some disclosures not according to the claimed invention, the ETL may have a thickness between <NUM> and <NUM>, inclusively.

In some embodiments of the present disclosure, the ETL may include a compact layer and a mesoporous layer, and the compact layer may be positioned between the mesoporous layer and the first contact layer. In some embodiments of the present disclosure, the third material may include at least one of spiro-OMeTAD, PTAA, NiO, CuSCN, CuPc, CuI, a graphene oxide, a carbon nanotube, and/or any suitable organic material. In some embodiments of the present disclosure, the fourth material may include at least one of gold, silver, copper, aluminum, nickel, chromium, a molybdenum oxide, a carbon nanotube, graphene, and/or a transparent conducting oxide. In some embodiments of the present disclosure, the second contact layer may have a thickness between <NUM> and <NUM>, inclusively. In some embodiments of the present disclosure, the fifth material may include a polymer.

Disclosed herein but not claimed is a method for manufacturing a solar cell module, where the method includes a first applying of a first solution of an electron transfer layer (ETL) precursor onto a first surface of a first contact layer having a first thickness, where the first applying results in a first liquid film on the first surface, the first liquid film transforms into the ETL that includes a first solid material and having a second surface, and the first applying is performed using at least one of spin coating, spray coating, blade coating, slot-die coating, inkjet printing, screen printing, electrodeposition, sputtering, evaporation, pulsed laser deposition, chemical vapor deposition, and/or atomic layer deposition. The first applying may be performed by spray coating. The first applying may be performed by spray pyrolysis. During the first applying, the first surface may be at a temperature between <NUM> and <NUM>. The ETL precursor may include titanium diisopropoxide bis(acetylacetonate).

Exemplary embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than limiting. The devices with layer thicknesses of the electron transfer layer beyond <NUM> as shown in <FIG>, <FIG>, <FIG>, <FIG> are reference examples not according to the claimed invention.

The present disclosure may address one or more of the problems and deficiencies of the prior art discussed above.

The present disclosure relates to PSCs suitable for full-scale use (e.g. industrial and/or commercial) and methods for manufacturing these PSCs. Large-area PSCs can be separated into smaller area sub-cells, which may then be series interconnected to form a solar module. The solar module integration avoids long distance charge transport in TCO substrates, thus reducing parasitic resistive losses. Solar module integration also increases the photo-voltage available from the modules. There are at least two approaches to constructing a solar module on a monolithic substrate. One is to deposit each functioning layer only onto the needed regions, either through a mask guided deposition or pattern-able printing techniques (e.g. screen printing). Another approach is to coat each layer on the entire substrate area and later separate the sub-cells with laser and/or mechanical scribing. Both methods generate "dead" regions depending on the resolution of the patterning or scribing methods used. The ratio of active area to substrate area is referred to as the geometric fill factor (GFF) of the module, with a higher GFF meaning a smaller dead area power loss due to the module integration. The first approach usually creates wider gap distances between sub-cells due to the lower resolution compared to the gap distances that can be achieved using laser scribing. The wider gap distances may result in erosion of the module's active area and reduced GFF of the modules.

One major difference between large-area solar modules (e.g. full-scale) and small-area single cells (e.g. lab-scale) is the contacts connecting individual sub-cells. Developing procedures to scribe sub-cells and make reliable and effective interconnections between them are of critical importance to fabricate large-scale solar modules with efficiencies as high as those demonstrated in single cells. Thus, the present disclosure demonstrates a fully scalable manufacturing method for perovskite module fabrication. In some embodiments of the present disclosure, a TiO<NUM> electron transport layer (ETL) may be deposited using spray pyrolysis, with both a perovskite absorber layer and a spiro-OMeTAD hole transport layer (HTL) deposited using blade coating. The influence of TiO<NUM> ETL thickness on the resistance of metal/TiO<NUM>/TCO interconnections in the resultant perovskite modules are described herein. The optimized ETL thickness to balance shunting and interconnection resistance is identified. With optimizations on the ETL thickness, blade coating HTL, and perovskite composition, an aperture PCE of <NUM>% and an aperture area of <NUM><NUM> was achieved for a <NUM>-cell perovskite module, with the cells in series, with gaps (the result of scribing) separating the individual cells from one another. This example is among the highest efficiencies of perovskite solar modules fabricated by scalable deposition methods.

The term "spray pyrolysis" refers in general to a process in which thins films may be deposited by spraying a solution containing precursors onto a heated surface, where the precursors react and/or thermally degrade to form the desired films, for example TiO<NUM>. In some embodiments of the present disclosure, the precursors for forming TiO<NUM> (titanium diisopropoxide bis(acetylacetonate) in a <NUM>-butanol solution) may be sprayed onto a heated substrate (e.g. glass) that is at a temperature between <NUM> and <NUM>, or between <NUM> and <NUM>. Further, the terms "mesoporous" layers and "compact" layers refer to the presence or absence, respectively, of pores in the layers. In some embodiments of the present disclosure, a mesoporous TiO<NUM> film (e.g. ETL film) may be formed from a plurality of interconnected TiO<NUM> nanoparticles having a characteristic length between <NUM> and <NUM>, wherein the interconnected nanoparticles also contain interstitial spaces, or pores, resulting in an overall empty volume in the film between <NUM>% and <NUM>%. In contrast, a compact TiO<NUM> film, formed for example by vapor phase deposition, has an overall empty pore volume equal to zero percent, or approaching zero percent.

Thus, in some embodiments of the present disclosure, one or more layers (e.g. a perovskite layer and/or a HTL) of a solar cell module may be deposited by blade coating. Blade coating may be performed at a speed between <NUM> meters/minute and <NUM>/min, or between <NUM>/min and <NUM>/min. Further, blade coating may be performed at a height between <NUM> and <NUM>, or between <NUM> and <NUM>. In some embodiments of the present disclosure, blade coating may apply a liquid precursor such that the applied liquid film has a wet film thickness between <NUM> and <NUM>, corresponding to a liquid precursor application rate between <NUM>/m<NUM> and <NUM>/m<NUM>, or between <NUM>/m<NUM> and <NUM>/m<NUM>.

<FIG>, <FIG>, and <FIG> illustrate that perovskites <NUM>, for example organic-inorganic halide perovskites, may organize into cubic crystalline structures with corner-sharing octahedra, as well as other crystalline structures such as tetragonal, hexagonal, and orthorhombic with either edge- or face-sharing octahedra, and may be described by the general formula ABX<NUM>, where X (<NUM>) is an anion and A (<NUM>) and B (<NUM>) are cations, typically of different sizes (A typically larger than B). <FIG> illustrates that a perovskite <NUM> may be organized into eight octahedra surrounding a central A-cation <NUM>, where each octahedra is formed by six X-anions <NUM> surrounding a central B-cation <NUM>. <FIG> illustrates that a perovskite <NUM> may be visualized as a cubic unit cell, where the B-cation <NUM> is positioned at the center of the cube, an A-cation <NUM> is positioned at each corner of the cube, and an X-anion <NUM> is face-centered on each face of the cube. <FIG> illustrates that a perovskite <NUM> may also be visualized as a cubic unit cell, where the B-cation <NUM> resides at the eight corners of a cube, while the A-cation <NUM> is located at the center of the cube and with <NUM> X-anions centrally located between B-cations along each edge of the unit cell. For both unit cells illustrated in <FIG> and <FIG>, the A-cations <NUM>, the B-cations <NUM>, and the X-anions <NUM> balance to the general formula ABX<NUM>, after accounting for the fractions of each atom shared with neighboring unit cells. For example, referring to <FIG>, the single B-cation <NUM> atom is not shared with any of the neighboring unit cells. However, each of the six X-anions <NUM> is shared between two unit cells, and each of the eight A-cations <NUM> is shared between eight unit cells. So, for the unit cell shown in <FIG>, the stoichiometry simplifies to B = <NUM>, A = <NUM>*<NUM> = <NUM>, and X = <NUM>*<NUM>=<NUM>, or ABX<NUM>. Similarly, referring again to <FIG>, since the A-cation is centrally positioned, it is not shared with any of the unit cells neighbors. However, each of the <NUM> X-anions <NUM> is shared between four neighboring unit cells, and each of the eight B-cations <NUM> is shared between eight neighboring unit cells, resulting in A = <NUM>, B = <NUM> *<NUM> = <NUM>, and X = <NUM>*<NUM> = <NUM>, or ABX<NUM>. Referring again to <FIG>, the X-anions <NUM> and the B-cations <NUM> are shown as aligned along an axis; e.g. where the angle at the X-anion <NUM> between two neighboring B-cations <NUM> is exactly <NUM> degrees, referred to herein as the tilt angle. However, a perovskite <NUM> may have may have a tilt angle not equal to <NUM> degrees. For example, some embodiments of the present disclosure may have a tilt angle between <NUM> and <NUM> degrees.

Typical inorganic perovskites include calcium titanium oxide (calcium titanate) minerals such as, for example, CaTiO<NUM> and SrTiO<NUM>. In some embodiments of the present invention, the A-cation <NUM> may include a nitrogen-containing organic compound such as an alkyl ammonium compound. The B-cation <NUM> may include a metal and the X-anion <NUM> may include a halogen. Additional examples for the A-cation <NUM> include organic cations and/or inorganic cations, for example Cs, Rb, K, Na, Li, and/or Fr. Organic A-cations <NUM> may be an alkyl ammonium cation, for example a C<NUM>-<NUM> alkyl ammonium cation, a C<NUM>-<NUM> alkyl ammonium cation, a C<NUM>-<NUM> alkyl ammonium cation, a C<NUM>-<NUM> alkyl ammonium cation, a C<NUM>-<NUM> alkyl ammonium cation, a C<NUM>-<NUM> alkyl ammonium cation, a C<NUM>-<NUM> alkyl ammonium cation, and/or a C<NUM> alkyl ammonium cation. Further examples of organic A-cations <NUM> include methylammonium (CH<NUM>NH<NUM>+), ethylammonium (CH<NUM>CH<NUM>NH<NUM>+), propylammonium (CH<NUM>CH<NUM> CH<NUM>NH<NUM>+), butylammonium (CH<NUM>CH<NUM> CH<NUM> CH<NUM>NH<NUM>+), formamidinium (NH<NUM>CH=NH<NUM>+), hydrazinium, acetylammonium, dimethylammonium, imidazolium, guanidinium and/or any other suitable nitrogen-containing or organic compound. In other examples, an A-cation <NUM> may include an alkylamine. Thus, an A-cation <NUM> may include an organic component with one or more amine groups. For example, an A-cation <NUM> may be an alkyl diamine halide such as formamidinium (CH(NH<NUM>)<NUM>). Thus, the A-cation <NUM> may include an organic constituent in combination with a nitrogen constituent. In some cases, the organic constituent may be an alkyl group such as straight-chain or branched saturated hydrocarbon group having from <NUM> to <NUM> carbon atoms. In some embodiments, an alkyl group may have from <NUM> to <NUM> carbon atoms. Examples of alkyl groups include methyl (C<NUM>), ethyl (C<NUM>), n-propyl (C<NUM>), isopropyl (C<NUM>), n-butyl (C<NUM>), tert-butyl (C<NUM>), sec-butyl (C<NUM>), iso-butyl (C<NUM>), n-pentyl (C<NUM>), <NUM>-pentanyl (C<NUM>), amyl (C<NUM>), neopentyl (C<NUM>), <NUM>-methyl-<NUM>-butanyl (C<NUM>), tertiary amyl (C<NUM>), and n-hexyl (C<NUM>). Additional examples of alkyl groups include n-heptyl (C<NUM>), n-octyl (C<NUM>) and the like.

Examples of metal B-cations <NUM> include, for example, lead, tin, germanium, and or any other <NUM>+ valence state metal that can charge-balance the perovskite <NUM>. Further examples include transition metals in the <NUM>+ state such as Mn, Mg, Zn, Cd, and/or lanthanides such as Eu. B-cations may also include elements in the <NUM>+ valence state, as described below, including for example, Bi, La, and/or Y. Examples for X-anions <NUM> include halogens: e.g. fluorine, chlorine, bromine, iodine and/or astatine. In some cases, a perovskite may include more than one X-anion <NUM>, for example pairs of halogens; chlorine and iodine, bromine and iodine, and/or any other suitable pairing of halogens. In other cases, the perovskite halide <NUM> may include two or more halogens of fluorine, chlorine, bromine, iodine, and/or astatine.

Thus, the A-cation <NUM>, the B-cations <NUM>, and X-anion <NUM> may be selected within the general formula of ABX<NUM> to produce a wide variety of perovskites <NUM>, including, for example, methylammonium lead triiodide (CH<NUM>NH<NUM>PbI<NUM>), and mixed halide perovskites such as CH<NUM>NH<NUM>PbI<NUM>-xClx and CH<NUM>NH<NUM>PbI<NUM>-xBrx. Thus, a perovskite <NUM> may have more than one halogen element, where the various halogen elements are present in non-integer quantities; e.g. x is not equal to <NUM>, <NUM>, or <NUM>. In addition, perovskites can form three-dimensional (<NUM>-D), two-dimensional (<NUM>-D), one-dimensional (<NUM>-D) or zero-dimensional (<NUM>-D) networks, possessing the same unit structure. As described herein, the A-cation <NUM> of a perovskite <NUM>, may include one or more A-cations, for example, one or more of cesium, FA, MA, etc. Similarly, the B-cation <NUM> of a perovskite <NUM>, may include one or more B-cations, for example, one or more of lead, tin, germanium, etc. Similarly, the anion <NUM> of a perovskite <NUM> may include one or more anions, for example, one or more halogens. Any combination is possible provided that the charges balance.

For example, a perovskite having the basic crystal structure illustrated in <FIG>, in at least one of a cubic, orthorhombic, and/or tetragonal structure, may have other compositions resulting from the combination of the cations having various valence states in addition to the <NUM>+ state and/or <NUM>+ state described above for lead and alkyl ammonium cations; e.g. compositions other than AB<NUM>+X<NUM> (where A is one or more cations, or for a mixed perovskite where A is two or more cations). Thus, the methods described herein may be utilized to create novel mixed cation materials having the composition of a double perovskite (elpasolites), A<NUM>B<NUM>+B<NUM>+X<NUM>, with an example of such a composition being Cs<NUM>BiAgCl<NUM> and Cs<NUM>CuBiI<NUM>. Another example of a composition covered within the scope of the present disclosure is described by A<NUM>B<NUM>+X<NUM>, for example Cs<NUM>PbI<NUM> and Cs<NUM>SnI<NUM>. Yet another example is described by A<NUM>B<NUM><NUM>+X<NUM>, for example Cs<NUM>Sb<NUM>I<NUM>. For each of these examples, A is one or more cations, or for a mixed perovskite, A is two or more cations.

<FIG> and <FIG> illustrate non-ideal and ideal perovskite-containing modules <NUM>, respectively. Referring to <FIG>, an ideal module <NUM> may include two or more cells (two shown; 202A and 202B) connected in series by an interconnection <NUM>. An interconnection <NUM> is a physical connection between the second contact layer (e.g. 260B) of a first cell (e.g. 202A) with the first contact layer (e.g. 220B) of a second cell (e.g. 202B). This results in the addition of the voltage produced by each cell (202A and 202B) in the series of cells in the module <NUM>, with the current flowing through each cell remaining constant.

Each cell (202A and 202B) may be positioned on a substrate <NUM>. The substrate <NUM> may be constructed of any suitable material including at least one of glass, foil and/or plastic. A substrate <NUM> may have a thickness between several micrometers and several millimeters. A first contact layer <NUM>, for example a transparent conducting oxide (TCO) layer, may be positioned in direct physical contact with the substrate <NUM>. TCOs may include at least one of fluorine-doped tin oxide (FTO), indium-doped tin oxide (ITO), indium zinc oxide (IZO), gallium zinc oxide (GZO), and/or aluminum-doped zinc oxide (AZO). In some embodiments of the present disclosure, a transparent first contact layer <NUM> may be in the form of at least one of a metal nanowire, a carbon nanotube, a p-type transparent conducting layer, a CuS-based TCO, PEDOT:PSS, and/or a graphene sheet. Gaps (<NUM>, <NUM>, and <NUM>) may separate the first contact layer <NUM> into different sections (e.g. 220A and 220B) corresponding to TCO sections for each respective cell. Each gap (<NUM>, <NUM>, and <NUM>) may have a width between about <NUM> and about <NUM>, or between about <NUM> to <NUM>. The module <NUM> may also include an electron transport layer (ETL) <NUM> positioned in contact with the first contact layer <NUM> (e.g. a TCO), such that the first contact layer <NUM> may be positioned between the substrate <NUM> and the ETL <NUM>. The ETL <NUM> shown in <FIG> may also fill in the gaps, resulting in the ETL filled gaps (290A and 290B; corresponding to P1 in <FIG>), where the ETL material extends through the thickness of the first contact layer <NUM> from the plane occupied by the ETL <NUM> to the surface of the underlying substrate <NUM>. Referring to the portion of HTL <NUM> and perovskite layer <NUM> positioned between the contact layer filled gap 280B and empty gap 270B, this material does not produce any power. Therefore, it is desirable to minimize the width of this material to as small as possible, e.g. approaching zero nanometers.

In disclosures provided herein but not according to the claimed invention, an ETL <NUM> may be constructed of at least one of TiO<NUM>, ZnO, SnO<NUM>, BaSnO<NUM>, and/or SrTiO<NUM>, having a thickness between about <NUM> and about <NUM>. In some embodiments of the present disclosure, an ETL <NUM> may include a first compact layer of these materials and a second mesoporous layer of these materials. Each cell (202A and 202B) of the module <NUM> may contain a perovskite layer <NUM>, for example an organic-inorganic halide perovskite, as an active layer. So, each cell (202A and 202B) may have its own respective perovskite layer (240A and 240B), positioned in direct physical contact with the underlying ETL <NUM>. The perovskite layer <NUM> may be constructed of any suitable perovskite having a crystal structure as illustrated in <FIG> and described above.

The ideal example of a module <NUM>, shown in <FIG>, may also include a hole transport layer (HTL) <NUM> positioned in direct physical contact with the perovskite layer <NUM>, such that the perovskite layer <NUM> may be positioned between the HTL <NUM> and the ETL <NUM>. The HTL <NUM> may be constructed of at least one of spiro-OMeTAD, PTAA, NiO, CuSCN, CuPc, graphene oxide, carbon nanotubes, CuI, and/or an organic material having a thickness between about <NUM> and about <NUM>. As shown in <FIG>, the perovskite layer <NUM> and the HTL <NUM> may be processed to form gaps that separate each into distinct sections for each cell (202A and 202B). So, the perovskite layer <NUM> may be separated into a first perovskite layer 240A for the first cell 202A and a second perovskite layer 240B for the second cell 202B by at least one gap, where both cells are positioned substantially within the same horizontal plane.

Finally, the ideal module <NUM>, as shown in <FIG>, may include a second contact layer <NUM> positioned in direct physical contact with the HTL <NUM>. The second contact layer <NUM> may be constructed of any suitable metal and/or conductive oxide, with examples including at least one of gold, Ag, MoOx/Al, Cu, carbon nanotube, graphene, Ni, Cr<NUM>O<NUM>/Cr, and/or TCO, having a thickness between about <NUM> and about <NUM>, or between about <NUM> and about <NUM>. The contact layer <NUM> may fill in the gaps separating the perovskite layer <NUM> into different sections (e.g. 240A and 240B), resulting in contact layer filled gaps (280A and 280B). In some embodiments, the contact layer filled gaps (280A and 280B, corresponding to P2 in <FIG>) may pass perpendicularly through the thickness of the perovskite layer <NUM> and the thickness of the ETL <NUM>, such that the contact layer filled gaps (280A and 280B) extend from the plane of the second contact layer <NUM> to the surface of the underlying first contact layer <NUM>. This is beneficial because removal of the ETL <NUM> enables direct electrical contact of the first contact layer <NUM> with the second contact layer <NUM>. Otherwise, any remaining ETL material can form a Schottky contact having large contact resistances (see <FIG>, which demonstrates that as an ETL <NUM> of TiO<NUM> thickness is reduced from <NUM> to <NUM>, the I-V curves changed from a Schottky diode behavior (S-shape) to an ohmic behavior (straight line)). Lastly, the ideal module <NUM> of <FIG> may include at least one empty gap (270A and 270B corresponding to P3 in <FIG>), which traverses perpendicularly across the entire thicknesses of the second contact layer <NUM> and the HTL <NUM>, and across the perovskite layer <NUM>. Additionally, the empty gaps (270A and 270B ) may be filled with an insulating material (not shown) to add structural integrity and environmental protection to the thin film device layers. Referring no to the non-ideal module <NUM> of <FIG>, this module does not have contact layer filled gaps <NUM>, or empty gaps <NUM> that extend all the way through the HTL <NUM>, the perovskite layer <NUM>, and the ETL <NUM>, to the surface of the underlying first contact layer <NUM>.

<FIG> illustrates an example of a method <NUM> for producing a module <NUM> like the modules <NUM> shown in <FIG> and <FIG>, with the objective of producing the ideal module <NUM> of <FIG>. The method <NUM> of this example sequentially produces a module, where the module passes through various intermediate incomplete forms. These intermediate forms are referred to herein as "intermediate modules". The method <NUM> may begin with the depositing of a first contact layer <NUM> (e.g. TCO layer) onto a substrate, resulting in a first intermediate module <NUM>. The depositing of the TCO layer <NUM> may include at least one of radio frequency sputtering, direct current sputtering, evaporation, and/or spray pyrolysis. The first intermediate module <NUM> having a first contact layer <NUM> on a substrate <NUM> may then be further processed by the forming of a first gap <NUM> (ETL filled gap <NUM> of <FIG>; P1 of <FIG>) onto the surface of the first contact layer <NUM>; e.g. by patterning using laser scribing, mechanical etching, and/or chemical etching. Thus, the forming of the first gap <NUM> may result in a second intermediate module <NUM> having a patterned first contact layer <NUM>, having one or more first gaps. The second intermediate module <NUM> may then be processed by the depositing of an ETL <NUM> onto at least a portion of the first contact layer <NUM>, resulting in the formation of a third intermediate module <NUM>. The depositing of the ETL <NUM> may be achieved by at least one of spin coating, spray coating, blade coating, slot-die coating, inkjet printing, screen printing, electrodeposition, sputtering, evaporation, PLD, CVD, and/or ALD, at a temperature between about room temperature and about <NUM>. During the depositing of the ETL <NUM>, at least some of the first gaps formed during the forming of the first gap <NUM> may be filled with the ETL <NUM>, resulting in ETL filled gaps <NUM>, such that the ETL <NUM> penetrates the depth of the first gaps to pass completely pass through the thickness of the first contact layer <NUM> and physically contact the underlying substrate <NUM>.

Referring again to <FIG>, the method <NUM> may then continue with the depositing of a perovskite layer <NUM> onto the surface of the ETL, resulting in the formation of a fourth intermediate module <NUM>. The depositing of the perovskite layer <NUM> may be accomplished by a solution processing method, with examples including at least one of spraying, blade coating, curtain coating, dip coating, spin coating, slot-die coating, inkjet printing, screen printing, electrodeposition, evaporation, and/or CVD, at a temperature between about room temperature and about <NUM>. The depositing of the perovskite layer <NUM> may result in a liquid perovskite layer positioned on the ETL <NUM> and a fourth intermediate module 337A having a liquid layer positioned on its surface. Thus, the liquid perovskite layer, and the fourth intermediate module 337A, may undergo a first treating <NUM> to convert the liquid perovskite layer to a solid perovskite layer; e.g. by thermal annealing, at a temperature between about room temperature and about <NUM>, at a duration between about <NUM> seconds and about <NUM> minutes. As a result, the first treating <NUM> may result in the conversion of the liquid phase perovskite of the fourth intermediate module 337A to a fourth intermediate module 337B having a solid perovskite layer <NUM> positioned on the ETL.

Referring again to <FIG>, the fourth intermediate module 337B having a solid perovskite layer <NUM> may then be processed further by the depositing of a HTL <NUM> onto the perovskite layer <NUM>. The depositing of the HTL <NUM> may be accomplished by a solution processing method, with examples including at least one of spraying, blade coating, curtain coating, dip coating, spin coating, slot-die coating, inkjet printing, screen printing, sputtering, evaporation, PLD, CVD, and/or ALD, at a temperature between about room temperature and about <NUM>. Like the depositing of a perovskite layer <NUM>, the depositing of the HTL <NUM> may result in the formation of a fifth intermediate module 344A having a liquid HTL positioned on the perovskite layer. Thus, and the fifth intermediate module 344A having a liquid phase HTL, may undergo a second treating <NUM> to convert the liquid HTL to a solid HTL <NUM>, resulting in fifth intermediate module 344B; e.g. by thermal annealing at a temperature between about room temperature and about <NUM>, at a duration between about <NUM> seconds and about <NUM> minutes. As a result, the second treating <NUM> may result in the formation of a fifth intermediate module 344B having a solid HTL <NUM> positioned on the solid perovskite layer <NUM>. In some embodiments of the present disclosure, only one treating step may be used to simultaneously convert both a liquid perovskite layer and a liquid HTL to solid forms of each, <NUM> and <NUM>, respectively.

The fifth intermediate module, having a HTL <NUM>, may then be processed by the forming of a second gap <NUM> onto the surface of the HTL <NUM>; e.g. patterning by laser scribing, mechanical etching, and/or chemical etching. Thus, the forming of the second gap <NUM> may result in a sixth intermediate module <NUM> having a patterned HTL <NUM>, having one or more second gaps. The patterning may completely penetrate the thickness of the HTL <NUM>, the thickness of the underlying perovskite layer <NUM>, and the thickness of the underlying ETL <NUM>. Subsequent to the forming of the second gap <NUM>, the sixth intermediate module <NUM> having a patterned HTL surface may be processed by the depositing of a second contact layer <NUM> onto the patterned surface of the HTL <NUM>. The depositing of the second contact layer <NUM> may be accomplished by at least one of thermal evaporation, spin coating, spray coating, blade coating, slot-die coating, inkjet printing, screen printing, sputtering, PLD, CVD, and/or ALD, at a temperature between about room temperature and about <NUM>, resulting in the forming of a seventh intermediate module <NUM>. The second contact layer <NUM> may completely fill the second gaps, resulting in the ETL filled gaps <NUM> shown in <FIG>, such that the second contact layer <NUM> is in in direct physical contact with the first contact layer <NUM>.

Finally, the method <NUM> may conclude with the forming of a third gap <NUM> (the empty gap <NUM> of <FIG>) onto the seventh intermediate module <NUM>, resulting in a completed final module <NUM>, similar to that shown in <FIG>. The third gap, may completely penetrate the thicknesses of each of the second contact layer <NUM>, the HTL <NUM>, the perovskite layer <NUM>, and the ETL <NUM>, such that the third gap passes through the module <NUM> to the surface of the first contact layer <NUM>. In some embodiments of the present disclosure, the forming of the third gap <NUM> may be accomplished by laser scribing, mechanical etching, and/or chemical etching. Thus, the forming of the third gap <NUM> may result in the final module <NUM> having a patterned contact layer, having one or more third gaps.

In some embodiments of the present disclosure, a (n-i-p) PSC architecture includes a stack of device layers glass/TCO/ETL/perovskite/HTL/metal, corresponding to substrate/first contact layer/ETL/perovskite layer/HTL/second contact layer. The ETL and the HTL may be constructed of TiO<NUM> and doped spiro-OMeTAD, respectively. The physical properties of the TiO<NUM> ETL (e.g., thickness, roughness, porosity, and conductivity) may strongly influence the device performance as well as the hysteresis behavior largely due to the effects of the ETL on the kinetics of electron extraction. In general, an ETL should be pinhole free to minimize shunting and to enable selective/effective extraction and conduction of electrons away from the perovskite layer. The ETL thickness may need to be optimized for high-efficiency PSCs. In some embodiments of the present disclosure, spray-pyrolysis coating may be used to deposit compact TiO<NUM> (c-TiO<NUM>) ETLs onto a device. In some disclosures provided herein but not claimed, the thickness of a TiO<NUM> layer (between <NUM> and <NUM>) may be defined by controlling at least one of the number of coating cycles, the rate of spraying, the concentration of the TiO<NUM> precursor, and/or the total spray volume of the TiO<NUM> precursor (see <FIG> and <FIG>). Described herein, are the impacts of the TiO<NUM> ETL layer on the characteristics of perovskite-containing modules prepared by blade coating methods using a perovskite ink. In some embodiments of the present disclosure, the ETL precursor (e.g. TiO<NUM> precursor) may be deposited (e.g. sprayed) onto a surface of a module (e.g. the surface of the first contact layer) at a rate between <NUM>/cm<NUM> to <NUM>/cm<NUM>.

<FIG> shows the photocurrent-voltage (J-V) curves of MAPbI<NUM> perovskite modules having four individual cells series connected on a monolithic substrate. The modules were prepared using a liquid perovskite precursor composition and blade coating process. In some embodiments of the coating process, blade coating was performed on a Zehntner-Automatic film applicator coater using Zehntner ZUA <NUM> blade at room temperature. The gap between the blade and the top substrate was fixed at <NUM> and the speed of coating was <NUM>/s. Once the precursor ink was dispensed on to the substrate by blade coating, the substrate was transferred into a diethyl ether bath for solvent extraction, after about <NUM> minute of drying. A perovskite film crystalized in the ether bath in about <NUM> minute. Further thermal annealing was conducted after the bath at <NUM> for about one to two minutes. Examples of the resultant blade-coated films are shown in <FIG>. These modules have a device structure of FTO/c-TiO<NUM>/perovskite/doped Spiro-OMeTAD/gold (corresponding to first contact layer/ETL/perovskite layer/HTL/second contact layer), with spiro-OMeTAD deposited by spin coating and a gold electrode deposited by thermal evaporation. Scribing was used to form gaps (e.g. P1 - Reference number <NUM>; P2 - <NUM>; and P3 - <NUM> referring to <FIG> and <FIG>, respectively) to isolate and form interconnections between individual cells to complete the manufacture of the module on single substrate. A picture of the typical <NUM>-cell mini-module is shown in the inset of <FIG>; the aperture area of this example module was about <NUM><NUM>. Optical microscopy images of typical P1, P2, and P3 scribing lines (gaps) are shown in <FIG>, from which the geometrical fill factor or GFF of the module was estimated to be about <NUM>%. The J-V curves (reverse scan) indicate that as the TiO<NUM> film (ETL) thickness was increased from <NUM> to <NUM>, the fill factor (FF) (where FF is defined as the maximum power point dived by the product of VOC and ISC) decreased significantly from about <NUM> to <NUM>, without significant changes in the short-circuit current density (Jsc) and open-circuit voltage (Voc), leading to the aperture PCE dropped from about <NUM>% to <NUM>%. Because these modules display moderate hysteresis-which will be discussed later- the stabilized power output (SPO) measurement under continuous one-sun illumination was also evaluated. Consistent with the PCE measured at J-V scans, the SPO efficiency also decreased from <NUM>% to <NUM>% when the TiO<NUM> film thickness was increased from about <NUM> to <NUM>. It is worth noting that the SPO efficiency was closer to the PCE resulting from the reverse scan J-V curves. The detailed J-V parameters along with SPO values are shown in Table <NUM>.

The TiO<NUM> (ETL) film thickness significantly affected PV performances, with large differences in performances evident between the larger perovskite modules and the smaller lab-scale devices (~<NUM><NUM> active area). The statistics of PV parameters for both modules and smaller-area devices (cells) are compared in <FIG>, <FIG>, <FIG>, and <FIG>. For the purpose of comparison, the Jsc and Voc values for the modules are shown on a per-cell basis. When the c-TiO<NUM> layer thickness was increased from about <NUM> to <NUM>, the PCE of the lab-scale devices improved from about <NUM>% to <NUM>%, which is mainly attributed to the increased Jsc and Voc. In comparison to lab-scale devices, the Jsc of mini-modules was significantly lower, which may be attributed to the GFF of <NUM>% corresponding to about <NUM>% dead area resulting from the module interconnections. The Voc values were comparable between the lab-scale devices and the larger modules. The biggest difference was the FF, which stayed almost unchanged around <NUM>-<NUM> for the lab-scale devices but decreased substantially from <NUM> to <NUM> when the c-TiO<NUM> film (ETL) thickness was increased from about <NUM> to <NUM>. This suggests that different factors need to be taken into consideration for device optimization when transitioning from smaller-area lab-scale cells to larger surface area modules, even when the same stack layers are used in both types of devices.

To understand the different TiO<NUM> ETL thickness dependence between smaller-area cells and larger area modules, it is necessary to examine how the perovskite modules are constructed in comparison to the standard process of constructing smaller-area devices. Referring again to <FIG> and <FIG>, which show the schematics of a module <NUM> having an n-i-p architecture. Such a perovskite solar module <NUM> may include individual cells (e.g. 202A and 202B) serially interconnected on the same substrate <NUM>. In some embodiments of the present disclosure, three scribing processes (P1, P2 and P3) may be needed to complete a module, corresponding to an ETL filled gap <NUM>, a contact layer filled gap <NUM>, and an empty gap <NUM>, respectively. Each ETL filled gap may separate the first contact layer 220A of the first cell 202A from the first contact layer of the adjacent cell; e.g. first contact layer 220B of second cell 202B. Each contact layer filled gap <NUM> passing through the perovskite layer <NUM> enables the electrical connection of the first contact layer <NUM> with the second contact layer <NUM> of adjacent sub-cells (202A and 202B); each empty gap <NUM> may separate the second contact layer 260A of a first cell 202A from the second contact layer 260B of its adjacent second cell 202B. In a preferred situation, as shown in <FIG>, each contact layer filled gap <NUM> should scribe all the way through the electron transfer layer <NUM> to the top surface of the underlying first contact layer <NUM>. Subsequent deposition of a second contact layer <NUM> (e.g., Au) may make direct contact with the first contact layer <NUM>, forming the interconnections <NUM> between neighboring cells (202A and 202B). However, the TiO<NUM> ETL layer <NUM> may exhibit similar material hardness and optical properties as the underlying first contact layer <NUM> (e.g., FTO), which can present a challenge for both mechanical scribing and laser scribing for removing the oxide layer, without damaging the underlying TCO layer. Such a challenge may be similar for other oxides (e.g., ZnO and SnO<NUM>) that may be used as ETLs in perovskite devices. Thus, in practice, a non-ideal interconnection in n-i-p perovskite modules may exists, where the second contact layer <NUM> is connected to the first contact layer <NUM> through a portion of the ETL <NUM> (see <FIG>). Because a module <NUM> includes multiple cells (e.g. 202A and 202B) with interconnections <NUM> and a large photocurrent is concentrated at the relatively narrow interconnections <NUM>, the contact behavior at these interconnections becomes important to the operation of perovskite modules. In contrast, such interconnection <NUM> issues do not exist in small-area lab-scale devices.

<FIG> illustrates the contact behavior of FTO/TiO<NUM>/Au only (no perovskite layer, HTL, etc.), which represents the actual materials of the interconnects used and tested in the perovskite module. These curves were generated by applying a voltage sweep of the FTO/TiO<NUM>/Au and FTO/Au devices. The measurements were done under one-sun illumination through the glass side, mimicking the actual operating conditions of perovskite modules. The contact shows a clear diode rectification behavior when the TiO<NUM> (ETL) thickness was about <NUM>. This diode behavior changed to a resistive (ohmic) behavior as the TiO<NUM> film (ETL) thickness was reduced to about <NUM>. All of these interconnection contact resistances contributed to the series resistance of the module, leading to significant parasitic loss and contact voltage loss especially in view of a large current flowing through the multiple interconnection contacts within the module. Such parasitic and voltage loss is expected to strongly affect the FF and Voc of the modules as observed in <FIG> and <FIG>, respectively.

PSCs may be based on a n-i-p device stack and/or on a p-i-n (inverted) device stack with either planar or mesoporous TiO<NUM> ETLs deposited on TCOs. Other oxides such as ZnO and NiO may also be used in either normal or inverted module structures. These oxides materials normally exhibit material hardness and optical property similar to the TCO substrates such as FTO and ITO. This presents a challenge for mechanical scribing or laser scribing for removing these materials due to the potential for damaging the underlying first contact layer <NUM> during the P2 scribing processing. The results presented herein suggest that any residual ETL, in this case an oxide layer, remaining after the P2 scribing may cause parasitic resistive losses in the final perovskite modules. Optimization of the oxide thickness for single cells versus larger surface area modules may be significantly different due to the interconnection resistive loss issues. Finally, it is worth noting that although the modules based on ~<NUM> TiO<NUM> ETL displayed good module performance, the resistance of FTO/TiO<NUM>/Au contact, corresponding to the non-ideal case of <FIG>, was still about a factor of two larger than that of FTO/Au (without TiO<NUM> to simulate complete removal of the ETL), corresponding to the ideal case of <FIG>; this suggests that further improvement of module performance with higher FF can be expected with designs to fully address the interconnection contact issue.

Composition engineering via A-site cation alloying (e.g., methylammonium - MA, formamidinium - FA, cesium) may improve the performance of perovskite solar cells. MA-FA alloying may result in the scalable deposition of perovskite thin films when assisted with the use of a heated substrate and the adjusting of the solvent composition may provide a wide processing window for blade coating processing method to manufacture high-quality perovskite thin films. Therefore, such solvent strategies were utilized with blade coating methods for producing mixed-cation perovskites. Panels (a) and (b) of <FIG> compare the top view SEM images of the MAPbI<NUM> and MA<NUM>FA<NUM>PbI<NUM> thin films prepared by using a blade coating approach. The grain morphology looks similar and both films were compact with no pinholes, which is important to ensure high-performance perovskite solar cells. The carrier lifetime of these two types of perovskite thin films were examined by TRPL measurement. <FIG> shows that MA<NUM>FA<NUM>PbI<NUM> has a much longer carrier lifetime than MAPbI<NUM> implying a reduced defect density with mixed cations.

Perovskite solar cells were prepared to compare the device characteristics. The typical J-V curves and EQE spectra of lab-scale PSCs (~<NUM><NUM> active area) using MAPbI<NUM> and MA<NUM>FA<NUM>PbI<NUM> are compared in <FIG> and <FIG>, respectively. In comparison to the MAPbI<NUM> PSC, the MA<NUM>FA<NUM>PbI<NUM> PSC shows improved PCE and reduced hysteresis. The detailed PV parameters are shown in Table <NUM>. The PCE improvement is largely attributed to higher Jsc and FF with minimum change in Voc. The higher Jsc for MA<NUM>FA<NUM>PbI<NUM> PSC is consistent with the improved EQE spectrum with a wider photo-response toward to the near infrared region. The long wavelength onset of EQE spectrum increases by about <NUM> when the perovskite composition was changed from MAPbI<NUM> to MA<NUM>FA<NUM>PbI<NUM>, corresponding to about <NUM> meV reduction of the bandgap. Despite the smaller bandgap, the Voc was only affected by a few mV, which is consistent with the reduced defect density observed for the MA<NUM>FA<NUM>PbI<NUM> perovskite composition shown by TRPL.

To achieve large scale production of perovskite modules, it is important to have fully scalable deposition methods for producing all device layers, including the perovskite active layer and the charge transport layers (e.g. ETL and HTL). For the PSC device structures used in this study, the TiO<NUM> ETL was prepared by spray pyrolysis, which is scalable and suitable for large area module fabrication. In addition, as described herein, blade coating was implemented to produce a spiro-OMeTAD HTL with a composition that is also useful for application using a spin coating process. The blade coating method using the spiro-OMeTAD composition performed well. An example of the HTL solution includes <NUM> <NUM>,<NUM>',<NUM>,<NUM>'-tetrakis(N,N-dip-methoxyphenylamine)-<NUM>,<NUM>'-spirobifluorene (Spiro-MeOTAD; Merck), <NUM>µL bis(trifluoromethane) sulfonimide lithium salt stock solution (<NUM> Li-TFSI in <NUM> acetonitrile), and <NUM>µL <NUM>-tert-butylpyridine (TBP), <NUM>µL FK102 Co(III) TFSI solution (<NUM>/mL in acetonitrile), and <NUM> chlorobenzene solvent. <FIG> shows the cross-section SEM image of the full device stack consisting of spiro-OMeTAD HTL and MA<NUM>FA<NUM>PbI<NUM> perovskite layer both prepared by blade coating. The perovskite layer thickness is about <NUM> whereas the spiro-OMeTAD layer thickness is about <NUM>-<NUM>. The top view SEM image of the resultant blade-coated spiro-OMeTAD thin film is shown in <FIG>. The film is continuous and pinhole-free. <FIG> shows the J-V curves (with both forward and reverse scans) of the best-performing four-cell perovskite module with blade coating applied perovskite layer and HTL. The aperture (~<NUM><NUM>) PCE from reverse scan is about <NUM>% with a Jsc of ~<NUM> mA/cm<NUM>, Voc of ~<NUM> V, and FF of ~<NUM>. The corresponding per-cell Jsc and Voc are ~<NUM> mA/cm<NUM> and <NUM> V, respectively. The Voc value is very similar to that of the small-area (~<NUM><NUM> active area) PSC (see <FIG>), which confirms the high quality of both the blade-coated perovskite and spiro-OMeTAD layer over the larger-area substrate. Since the module showed clear hysteresis with forward-scan PCE of ~<NUM>% resulting mainly from the reduced FF (~<NUM>), the stabilized PCE (or SPO) under continuous one-sun illumination was also studied. The stable (aperture) PCE reached about <NUM>%, which is closer to the PCE determined from the reverse-scan J-V curve. It is worth noting that this aperture SPO efficiency of <NUM>% was achieved with a geometrical fill factor of about <NUM>% (see <FIG>), corresponding to an active-area module PCE of <NUM>%. Since a module's GFF can be improved to ><NUM>% with modern scribing techniques, it may be expected that perovskite modules with aperture PCE ><NUM>% may also be achieved.

With the capability of fully scalable deposition of a perovskite-containing device stack, a six-cell module was manufactured with a ~<NUM><NUM> aperture area, produced by blade coating of both the perovskite layer and HTL (see <FIG>. ) This further demonstrates the feasibility of the scalable deposition techniques demonstrated herein for producing larger scale perovskite solar modules. This six-cell module shows an aperture PCE of ~<NUM>% from reverse J-V scan (with Jsc of <NUM> mA/cm<NUM>, Voc of <NUM> V, and FF of <NUM>) and the aperture SPO efficiency of ~<NUM>% under continuous one-sun illumination (see <FIG>). The relatively low aperture SPO is in part caused a smaller GFF (~<NUM>%) for this <NUM>-cm<NUM> <NUM>-cell perovskite module, corresponding to an active-area PCE of about <NUM>%, which further confirms that blade coating of both the perovskite layer and the spiro-OMeTAD HTL is suitable for large scale perovskite module development.

The impact of other second contact layer materials on the contact characteristics was also evaluated, with the results summarized in <FIG>, <FIG>, and <FIG>. Interestingly, referring to <FIG> and <FIG>, when copper was used to replace gold as the second contact layer material, the second contact layer demonstrated ohmic behavior regardless of the thickness of the underlying TiO<NUM> ETL. The resistance was also much reduced in comparison to the Au/TiO<NUM> (contact layer/ETL) combination. Also, the Cu/TiO<NUM> (contact layer/ETL) combination exhibited very minimum dependence on the illumination condition. <FIG> illustrates the contact behavior of FTO/TiO<NUM>/MoOx/Al. Although the FTO/TiO<NUM>/MoOx/Al also demonstrated ohmic contact behavior, the resistance was significantly larger than the silver and copper contacts layers.

As used herein, the term "substantially" refers to the inherent error involved in any numerical measurement. For example, a gap extending substantially through a thickness of layer refers to a gap that extends exactly through the thickness, a gap that extends almost entirely through the thickness, and a gap that extends entirely through the thickness and into the underlying substrate. The exact depth of the gap for the second and third cases will depend on the method used for forming the gap, e.g. laser scribing, mechanical scribing, and/or chemical etching, and are known to one of ordinary skill in the art of scribing photovoltaic materials and surfaces.

Organic-Inorganic Halide Perovskite film deposition. For blade coating, <NUM> wt% equimolar ratio MAI and PbI<NUM> precursors with <NUM>% MACl additive in mixed solvent (NMP/DMF <NUM>/<NUM> weight ratio) were used. For mixed cations, <NUM>% (molar ratio) FAI and <NUM>% (molar ratio) MAI was used to replace MAI, and mixed solvent was adjusted to a higher DMF ratio (NMP/DMF <NUM>/<NUM> weight ratio). Blade coating was performed on a Zehntner-Automatic film applicator coater using Zehntner ZUA <NUM> blade at room temperature inside a N<NUM>-filled glovebox. The gap between blade and top substrate was fixed at <NUM> and the speed of coating was <NUM>/s. Once the precursor ink was dispensed on to the substrate by blade coating, the substrate was transferred into diethyl ether bath after about one minute of drying. Perovskite film crystalized in ether bath in <NUM> minute. A further thermal annealing was conducted after the bath at <NUM> with petri-dish covered for <NUM> seconds.

Device fabrication. For small area devices, a fluorine-doped tin oxide (FTO) substrate (TEC <NUM>, Hartford Glass Co) was patterned using hydrogen evolution etching method (zinc powder and <NUM> HCl solution). For larger surface area modules (MMs), <NUM>"×<NUM>" TEC <NUM> substrates were laser-scribed (<NUM>) with <NUM> spacing. Pre-patterned FTO was cleaned in base bath (<NUM> NaOH in ethanol) and then deposited with compact TiO<NUM> (c-TiO<NUM>) layers of various thickness by spray pyrolysis using <NUM> titanium diisopropoxide bis(acetylacetonate) in a <NUM>-butanol solution at <NUM>. The thickness of TiO<NUM> was controlled by the amount of sprayed solvent. Sprayed film was annealed at <NUM> for <NUM> hour. A thin C60 layer was deposited on the top of c-TiO<NUM>. The concentrations of C60 SAM (<NUM>-material) were <NUM>-<NUM>/ml in mixed solvent (chlorobenzene/tetrahydrofuran=<NUM>/<NUM> volume ratio). Blade coating was done with <NUM>/s speed with <NUM> gap and spin coating was done are <NUM> rpm for <NUM> seconds. The perovskite film was subsequently coated before the deposition of the hole transport layer (HTL). The HTL solution was composed of <NUM> <NUM>,<NUM>',<NUM>,<NUM>'-tetrakis(N,N-dip-methoxyphenylamine)-<NUM>,<NUM>'-spirobifluorene (Spiro-MeOTAD; Merck), <NUM>µL bis(trifluoromethane) sulfonimide lithium salt stock solution (<NUM> Li-TFSI in <NUM> acetonitrile), and <NUM>µL <NUM>-tert-butylpyridine (TBP), <NUM>µL FK102 Co(III) TFSI solution (<NUM>/mL in acetonitrile), and <NUM> chlorobenzene solvent. HTL was spin coated at <NUM>,<NUM> rpm for <NUM> seconds or blade coated at <NUM> gap with <NUM>/s speed. For MMs, the P2 gaps were scribed next to the P1 gaps using a mechanical scriber. A <NUM>-nm Au layer was deposited on the HTL layer by thermal evaporation for top contact. For MMs, the P3 gaps were further performed next to the P2 gaps to isolate top contacts. Edges of MMs were further deleted, and copper foil tape was attached for external wiring.

Film characterizations. X-ray diffraction (XRD) of the perovskite thin films was performed using an X-ray diffractometer (Rigaku D/Max <NUM>) with Cu Kα radiation. Absorption spectra were carried out by an ultraviolet-visible (UV/Vis) spectrometer (Cary-6000i). SEM was taken by NOVA <NUM> NanoSEM, FEI. Contact resistance measurement was conducted on FTO/c-TiO<NUM>/Au sandwiched structure using Keithley Source Meter (Model <NUM>) under one-sun condition.

Claim 1:
A perovskite (<NUM>) -containing solar cell module (<NUM>) comprising:
a substrate (<NUM>) having a first surface;
a first cell (202A); and
a second cell (202B), wherein:
each cell comprises, in order:
a first contact layer (<NUM>) comprising a first material, positioned on the substrate (<NUM>), and having a second surface and a first thickness;
an electron transfer layer (ETL) (<NUM>) comprising a second material and having a second thickness;
an active layer comprising the perovskite (<NUM>) and having a third thickness;
a hole transfer layer (HTL) (<NUM>) comprising a third material and having a fourth thickness; and
a second contact layer (<NUM>) comprising a fourth material and having a fifth thickness,
wherein:
the first cell (202A) and the second cell (202B) are electrically connected by a first gap (<NUM>) filled with the fourth material, and
the first gap (<NUM>) passes through the active layer, the HTL (<NUM>), and substantially through the ETL (<NUM>) to terminate at the second surface;
and characterised in that the second thickness of the ETL is <NUM> - <NUM>.